AT&T Inc
AT&T IncActive Patents
0
Total Holdings
2794
Patent Holdings
Filter in Explorer →| Patent No. | Title | Status | Filing Date | Grant Date | Claims | Actions |
|---|---|---|---|---|---|---|
| EP0510859A2 | Molded optical package utilizing leadframe technology | Expired / Lapsed | 1992-04-14 | — | 11 | Details |
| EP0413489A2 | Optical assembly comprising optical fiber coupling means | Expired / Lapsed | 1990-08-06 | — | 11 | Details |
| GB2060309A | Technique for estimation of displacement and/or velocity of… | Expired / Lapsed | 1980-02-25 | — | 0 | Details |
| WO1980001336A1 | A demultiplexing photodetector | Expired / Lapsed | 1979-12-04 | — | 0 | Details |
| DE1941336A1 | Speech signal processing device | Expired / Lapsed | 1969-08-14 | — | 0 | Details |
| GB684079A | Improvements in or relating to magnetic recorders, particul… | Expired / Lapsed | 1951-08-24 | — | 0 | Details |
| GB625501A | Electrical resistive elements and methods of making them | Expired / Lapsed | 1947-08-01 | — | 0 | Details |
| GB551209A | Rectifying contact detector systems for very short electric… | Expired / Lapsed | 1941-02-04 | — | 0 | Details |
| GB466063A | High frequency electromagnetic wave transmission apparatus | Expired / Lapsed | 1936-05-08 | — | 0 | Details |
| EP0479478B1 | Communications network arranged to transport connection ori… | Expired / Lapsed | 1991-09-25 | 2001-05-09 | 4 | Details |
| US6215859B1 | Delivery of urgent messages by integrated forced delivery a… | Expired / Lapsed | 1997-10-02 | 2001-04-10 | 18 | Details |
| US4731663A | Method and apparatus for color identification | Expired / Lapsed | 1987-05-20 | 1988-03-15 | 14 | Details |
| US4653048A | Method for interprocessor message accountability | Expired / Lapsed | 1984-05-14 | 1987-03-24 | 16 | Details |
| US4541980A | Methods of producing plastic-coated metallic members | Expired / Lapsed | 1984-01-09 | 1985-09-17 | 22 | Details |
| US4537663A | Method of and apparatus for plating using controlled progre… | Expired / Lapsed | 1982-07-27 | 1985-08-27 | 13 | Details |
| US4415901A | Low power beam switchable antenna arrangement | Expired / Lapsed | 1981-09-21 | 1983-11-15 | 3 | Details |
| US4412123A | Laminated electric heat generating member for reflow solder… | Expired / Lapsed | 1980-05-09 | 1983-10-25 | 7 | Details |
| US4399555A | Cellular high capacity mobile radiotelephone system with fl… | Expired / Lapsed | 1980-04-28 | 1983-08-16 | 15 | Details |
| US4383332A | High capacity digital mobile radio system | Expired / Lapsed | 1980-11-21 | 1983-05-10 | 20 | Details |
| US4379003A | Magnetic devices by selective reduction of oxides | Expired / Lapsed | 1980-07-30 | 1983-04-05 | 9 | Details |
| US4377315A | Circuit board keying arrangement | Expired / Lapsed | 1981-02-09 | 1983-03-22 | 15 | Details |
| US4357493A | Method and apparatus for storing announcements in a communi… | Expired / Lapsed | 1981-02-09 | 1982-11-02 | 18 | Details |
| US4355411A | Technique for efficient spectrum utilization in mobile radi… | Expired / Lapsed | 1981-06-22 | 1982-10-19 | 16 | Details |
| US4353086A | Silicon integrated circuits | Expired / Lapsed | 1980-05-07 | 1982-10-05 | 9 | Details |
| US4310722A | Mobile radiotelephone station two-way ranging system | Expired / Lapsed | 1979-12-17 | 1982-01-12 | 11 | Details |
| US4278538A | Methods and apparatus for sorting workpieces according to t… | Expired / Lapsed | 1979-04-10 | 1981-07-14 | 30 | Details |
| US4276448A | Electronic tone ringer | Expired / Lapsed | 1979-08-20 | 1981-06-30 | 22 | Details |
| US4275385A | Infrared personnel locator system | Expired / Lapsed | 1979-08-13 | 1981-06-23 | 25 | Details |
| US4275313A | Current limiting output circuit with output feedback | Expired / Lapsed | 1979-04-09 | 1981-06-23 | 6 | Details |
| US4261018A | Progressive image transmission | Expired / Lapsed | 1979-06-18 | 1981-04-07 | 13 | Details |
| US4253155A | Self-compensating measurement system | Expired / Lapsed | 1979-01-31 | 1981-02-24 | 18 | Details |
| US4238694A | Healing radiation defects in semiconductors | Expired / Lapsed | 1977-05-23 | 1980-12-09 | 18 | Details |
| US4229624A | Switching network control arrangement | Expired / Lapsed | 1978-12-21 | 1980-10-21 | 9 | Details |
| US4228528A | Memory with redundant rows and columns | Expired / Lapsed | 1979-02-09 | 1980-10-14 | 8 | Details |
| US4223973A | Circuit board keying arrangement | Expired / Lapsed | 1979-02-08 | 1980-09-23 | 16 | Details |
| US4222112A | Dynamic RAM organization for reducing peak current | Expired / Lapsed | 1979-02-09 | 1980-09-09 | 11 | Details |
| US4221997A | Articulated robot arm and method of moving same | Expired / Lapsed | 1978-12-18 | 1980-09-09 | 9 | Details |
| US4187027A | Servo-control alignment of nonlinear crystals | Expired / Lapsed | 1978-04-20 | 1980-02-05 | 7 | Details |
| US4181821A | Multiple template speech recognition system | Expired / Lapsed | 1978-10-31 | 1980-01-01 | 32 | Details |
| US4144411A | Cellular radiotelephone system structured for flexible use … | Expired / Lapsed | 1976-09-22 | 1979-03-13 | 29 | Details |
| US4139895A | Analog computer | Expired / Lapsed | 1977-08-19 | 1979-02-13 | 5 | Details |
| US4133976A | Predictive speech signal coding with reduced noise effects | Expired / Lapsed | 1978-04-07 | 1979-01-09 | 16 | Details |
| US4124774A | Telephone station coin memory and control system | Expired / Lapsed | 1977-07-27 | 1978-11-07 | 37 | Details |
| US4107474A | Bipolar transistor switching network crosspoint | Expired / Lapsed | 1977-05-31 | 1978-08-15 | 16 | Details |
| US4105973A | Multibeam, digitally modulated, time division, switched sat… | Expired / Lapsed | 1976-10-15 | 1978-08-08 | 23 | Details |
| US4095165A | Switching regulator control utilizing digital comparison te… | Expired / Lapsed | 1976-10-18 | 1978-06-13 | 11 | Details |
| US4090147A | Interferometric amplifier | Expired / Lapsed | 1977-07-20 | 1978-05-16 | 13 | Details |
| US4090221A | Apparatus for improving video signal-to-noise ratio | Expired / Lapsed | 1972-03-13 | 1978-05-16 | 13 | Details |
| US4081658A | Electrically heated soldering device | Expired / Lapsed | 1976-04-28 | 1978-03-28 | 4 | Details |
| US4074358A | Test set for measuring jitter distortion of data pulses | Expired / Lapsed | 1976-12-02 | 1978-02-14 | 21 | Details |
| US4054756A | Method and apparatus for automating special service call ha… | Expired / Lapsed | 1976-09-29 | 1977-10-18 | 31 | Details |
| US4034347A | Method and apparatus for controlling a multiprocessor system | Expired / Lapsed | 1975-08-08 | 1977-07-05 | 34 | Details |
| US4029900A | Digital synchronizing signal recovery circuits for a data r… | Expired / Lapsed | 1976-01-26 | 1977-06-14 | 31 | Details |
| US4028494A | Escrow telephone coin collection circuit and method | Expired / Lapsed | 1976-05-17 | 1977-06-07 | 16 | Details |
| US4027247A | Receiver especially for use as a diversity combining receiv… | Expired / Lapsed | 1975-11-11 | 1977-05-31 | 10 | Details |
| US4021314A | Method of depositing a metal on a surface | Expired / Lapsed | 1976-03-25 | 1977-05-03 | 5 | Details |
| US4012598A | Method and means for pulse receiver synchronization | Expired / Lapsed | 1976-01-14 | 1977-03-15 | 34 | Details |
| US4006304A | Apparatus for word synchronization in an optical communicat… | Expired / Lapsed | 1975-12-10 | 1977-02-01 | 6 | Details |
| US3991297A | Electrically heated soldering device | Expired / Lapsed | 1975-02-27 | 1976-11-09 | 7 | Details |
| US3990050A | Computer controlled automatic response system | Expired / Lapsed | 1974-09-25 | 1976-11-02 | 15 | Details |
| US3988535A | Automated positioning | Expired / Lapsed | 1975-11-04 | 1976-10-26 | 14 | Details |
| US3984626A | Picture signal coder | Expired / Lapsed | 1975-08-01 | 1976-10-05 | 21 | Details |
| US3983492A | Frequency scan and lock circuit for mobile radio channel se… | Expired / Lapsed | 1975-01-29 | 1976-09-28 | 6 | Details |
| US3982265A | Devices containing aluminum-V semiconductor and method for … | Expired / Lapsed | 1975-09-19 | 1976-09-21 | 17 | Details |
| US3982063A | Methods and apparatus for reducing the bandwidth of a video… | Expired / Lapsed | 1975-02-03 | 1976-09-21 | 12 | Details |
| US3979733A | Digital data communications system packet switch | Expired / Lapsed | 1975-05-09 | 1976-09-07 | 18 | Details |
| CA993519A | Diversity receiver suitable for large scale integration | Expired / Lapsed | 1972-05-25 | 1976-07-20 | 0 | Details |
| US3969016A | Low dispersion optical fiber wave guiding structures with p… | Expired / Lapsed | 1975-05-09 | 1976-07-13 | 4 | Details |
| US3958175A | Current limiting switching circuit | Expired / Lapsed | 1974-12-16 | 1976-05-18 | 10 | Details |
| US3949319A | High energy storage lasers employing perovskites containing… | Expired / Lapsed | 1974-09-12 | 1976-04-06 | 15 | Details |
| US3949121A | Method of forming a hydrophobic surface | Expired / Lapsed | 1973-12-12 | 1976-04-06 | 8 | Details |
| US3937899A | Tone detector using spectrum parameter estimation | Expired / Lapsed | 1975-01-30 | 1976-02-10 | 13 | Details |
| US3936631A | Optical fiber power tap | Expired / Lapsed | 1974-11-11 | 1976-02-03 | 12 | Details |
| US3935472A | Thin film liquid waveguide optical converter | Expired / Lapsed | 1975-03-14 | 1976-01-27 | 13 | Details |
| US3924080A | Zero suppression in pulse transmission systems | Expired / Lapsed | 1974-12-02 | 1975-12-02 | 27 | Details |
| US3920889A | Method and apparatus for crispening video signals by the us… | Expired / Lapsed | 1974-12-05 | 1975-11-18 | 23 | Details |
| US3914768A | Multiple-beam Cassegrainian antenna | Expired / Lapsed | 1974-01-31 | 1975-10-21 | 11 | Details |
| US3908084A | High frequency character receiver | Expired / Lapsed | 1974-10-07 | 1975-09-23 | 19 | Details |
| US3906454A | Computer monitoring system | Expired / Lapsed | 1973-05-18 | 1975-09-16 | 10 | Details |
| US3903363A | Automatic positioning system and method | Expired / Lapsed | 1974-05-31 | 1975-09-02 | 42 | Details |
| US3899634A | Video controlled positioning method and apparatus | Expired / Lapsed | 1973-07-11 | 1975-08-12 | 38 | Details |
| US3898443A | Memory fault correction system | Expired / Lapsed | 1973-10-29 | 1975-08-05 | 9 | Details |
| US3891804A | Asynchronous data transmission arrangement | Expired / Lapsed | 1973-09-12 | 1975-06-24 | 10 | Details |
| US3890493A | Circuitry for detecting faults in duplicate controllers | Expired / Lapsed | 1974-03-21 | 1975-06-17 | 21 | Details |
| US3883801A | Fault testing of logic circuits | Expired / Lapsed | 1973-11-07 | 1975-05-13 | 16 | Details |
| US3877782A | Electro-optical thin film device | Expired / Lapsed | 1974-01-23 | 1975-04-15 | 3 | Details |
| US3878463A | Automatic channel switching system | Expired / Lapsed | 1973-06-06 | 1975-04-15 | 26 | Details |
| US3866185A | Method and apparatus for gathering peak load traffic data | Expired / Lapsed | 1974-01-16 | 1975-02-11 | 17 | Details |
| US3865624A | Interconnection of electrical devices | Expired / Lapsed | 1970-06-29 | 1975-02-11 | 7 | Details |
| US3864161A | Method and apparatus for adjusting resonators formed on a p… | Expired / Lapsed | 1973-08-10 | 1975-02-04 | 22 | Details |
| US3860405A | Bonding of optical components | Expired / Lapsed | 1972-11-13 | 1975-01-14 | 7 | Details |
| US3859468A | Redundant data transmission arrangement | Expired / Lapsed | 1973-07-25 | 1975-01-07 | 14 | Details |
| US3858232A | Information storage devices | Expired / Lapsed | 1971-11-09 | 1974-12-31 | 39 | Details |
| US3844752A | Method for fabricating an optical fiber cable | Expired / Lapsed | 1973-08-20 | 1974-10-29 | 7 | Details |
| US3842259A | High voltage amplifier | Expired / Lapsed | 1973-09-24 | 1974-10-15 | 15 | Details |
| US3839646A | Field effect transistor logic gate with improved noise marg… | Expired / Lapsed | 1973-08-13 | 1974-10-01 | 12 | Details |
| US3837728A | Injected carrier guided wave deflector | Expired / Lapsed | 1973-09-26 | 1974-09-24 | 7 | Details |
| US3834819A | Thickness measuring | Expired / Lapsed | 1973-07-05 | 1974-09-10 | 19 | Details |
| US3833284A | Coupling arrangements for dielectric and metal-clad optical… | Expired / Lapsed | 1973-08-27 | 1974-09-03 | 6 | Details |
| US3833287A | Guest-host liquid crystal device | Expired / Lapsed | 1973-03-08 | 1974-09-03 | 8 | Details |
| US3828132A | Speech synthesis by concatenation of formant encoded words | Expired / Lapsed | 1970-10-30 | 1974-08-06 | 16 | Details |
| US3822928A | Thin film light guide | Expired / Lapsed | 1973-05-29 | 1974-07-09 | 6 | Details |
| US3823352A | Field effect transistor structures and methods | Expired / Lapsed | 1972-12-13 | 1974-07-09 | 15 | Details |
| US3820901A | Measurement of concentrations of components of a gaseous mi… | Expired / Lapsed | 1973-03-06 | 1974-06-28 | 6 | Details |
| US3819989A | Printed wiring board assembly | Expired / Lapsed | 1973-07-16 | 1974-06-25 | 12 | Details |
| US3819250A | Temperature sensitive fiber-optic devices | Expired / Lapsed | 1972-12-20 | 1974-06-25 | 6 | Details |
| US3819872A | Mobile telephone cellular switching system | Expired / Lapsed | 1972-07-10 | 1974-06-25 | 33 | Details |
| US3813613A | Laser employing a metallic pentaphosphate | Expired / Lapsed | 1973-04-02 | 1974-05-28 | 9 | Details |
| US3808068A | Differential etching of garnet materials | Expired / Lapsed | 1972-12-11 | 1974-04-30 | 13 | Details |
| US3806226A | Light-guiding interconnections for thin-film optical circui… | Expired / Lapsed | 1973-03-16 | 1974-04-23 | 9 | Details |
| US3803348A | Method and apparatus for encoding color video signals | Expired / Lapsed | 1973-01-22 | 1974-04-09 | 15 | Details |
| US3798560A | Adaptive transversal equalizer using a time-multiplexed sec… | Expired / Lapsed | 1973-01-29 | 1974-03-19 | 10 | Details |
| US3796999A | Locally erasable thermo-optic smectic liquid crystal storag… | Expired / Lapsed | 1972-10-19 | 1974-03-12 | 16 | Details |
| US3796837A | Network traffic control system | Expired / Lapsed | 1972-09-13 | 1974-03-12 | 15 | Details |
| US3793088A | Compatible pnp and npn devices in an integrated circuit | Expired / Lapsed | 1972-11-15 | 1974-02-19 | 4 | Details |
| US3793072A | Method of depositing a metal on a surface of a substrate | Expired / Lapsed | 1971-11-26 | 1974-02-19 | 2 | Details |
| US3793541A | Optical stimulated emission devices employing optical guidi… | Expired / Lapsed | 1970-12-21 | 1974-02-19 | 35 | Details |
| US3790902A | Fundamental transverse mode operation in solid state lasers | Expired / Lapsed | 1972-09-05 | 1974-02-05 | 12 | Details |
| US3784743A | Parallel data scrambler | Expired / Lapsed | 1972-08-23 | 1974-01-08 | 13 | Details |
| US3781796A | Error detecting translator | Expired / Lapsed | 1972-10-16 | 1973-12-25 | 5 | Details |
| US3781478A | Multiplex communication system | Expired / Lapsed | 1972-07-07 | 1973-12-25 | 57 | Details |
| US3781810A | Scheme for saving and restoring register contents in a data… | Expired / Lapsed | 1972-04-26 | 1973-12-25 | 5 | Details |
| US3780230A | Multifrequency tone receiver | Expired / Lapsed | 1972-11-10 | 1973-12-18 | 18 | Details |
| US3772617A | Method and arrangement for setting the remanent flux densit… | Expired / Lapsed | 1972-11-02 | 1973-11-13 | 18 | Details |
| US3771147A | Igfet memory system | Expired / Lapsed | 1972-12-04 | 1973-11-06 | 5 | Details |
| US3770350A | Method utilizing an optical fiber raman cell | Expired / Lapsed | 1972-07-24 | 1973-11-06 | 6 | Details |
| US3770606A | Schottky barrier diodes as impedance elements and method of… | Expired / Lapsed | 1970-11-17 | 1973-11-06 | 2 | Details |
| US3767847A | Frame-to-frame redundancy reduction system which transmits … | Expired / Lapsed | 1971-07-01 | 1973-10-23 | 16 | Details |
| US3764915A | Dynamic program control for channel assignment in mobile co… | Expired / Lapsed | 1971-06-25 | 1973-10-09 | 9 | Details |
| US3758720A | Circuit for incrementally phasing digital signals | Expired / Lapsed | 1971-12-27 | 1973-09-11 | 11 | Details |
| US3752970A | Digital attenuator | Expired / Lapsed | 1971-12-22 | 1973-08-14 | 12 | Details |
| US3750143A | Charge parceling integrator | Expired / Lapsed | 1972-07-18 | 1973-07-31 | 9 | Details |
| US3750058A | Waveguide structure utilizing compliant helical support | Expired / Lapsed | 1971-12-08 | 1973-07-31 | 7 | Details |
| US3743792A | Message waiting lamp arrangement | Expired / Lapsed | 1971-09-15 | 1973-07-03 | 12 | Details |
| US3743797A | Stroke coded keyboard switch assembly | Expired / Lapsed | 1971-08-30 | 1973-07-03 | 20 | Details |
| US3743962A | Thin film ring lasers | Expired / Lapsed | 1971-06-01 | 1973-07-03 | 4 | Details |
| US3742154A | Continuous inband testing of trunks with automatic trunk su… | Expired / Lapsed | 1971-12-30 | 1973-06-26 | 10 | Details |
| US3740476A | Speech signal pitch detector using prediction error data | Expired / Lapsed | 1971-07-09 | 1973-06-19 | 13 | Details |
| US3736373A | Conditional vertical subsampling in a video redundancy redu… | Expired / Lapsed | 1971-12-13 | 1973-05-29 | 15 | Details |
| US3733561A | High power, fundamental transverse mode operation in double… | Expired / Lapsed | 1971-07-27 | 1973-05-15 | 15 | Details |
| US3733440A | Semiautomatic call placement and message delivery arrangeme… | Expired / Lapsed | 1971-07-19 | 1973-05-15 | 22 | Details |
| US3731002A | Interconnected loop data block transmission system | Expired / Lapsed | 1970-10-08 | 1973-05-01 | 13 | Details |
| US3729253A | Optical system comprising a single element having a continu… | Expired / Lapsed | 1971-05-28 | 1973-04-24 | 56 | Details |
| US3725602A | Machine control by acoustic energy | Expired / Lapsed | 1970-12-28 | 1973-04-03 | 11 | Details |
| US3718781A | Integrity check equipment for automatic trunk substitution | Expired / Lapsed | 1971-12-30 | 1973-02-27 | 0 | Details |
| US3718778A | Pulse train checking circuit | Expired / Lapsed | 1971-12-23 | 1973-02-27 | 0 | Details |
| US3717850A | Programmed data processing with facilitated transfers | Expired / Lapsed | 1972-03-17 | 1973-02-20 | 80 | Details |
| US3717814A | Cophasing diversity communication system with pilot feedback | Expired / Lapsed | 1971-09-23 | 1973-02-20 | 14 | Details |
| US3715732A | Two-terminal npn-pnp transistor memory cell | Expired / Lapsed | 1971-12-09 | 1973-02-06 | 8 | Details |
| US3713042A | Stabilized mode-locked laser arrangement | Expired / Lapsed | 1971-05-27 | 1973-01-23 | 12 | Details |
| US3710279A | Apparatuses for trapping and accelerating neutral particles | Expired / Lapsed | 1969-12-15 | 1973-01-09 | 7 | Details |
| US3706076A | Programmable digital filter apparatus | Expired / Lapsed | 1970-12-21 | 1972-12-12 | 0 | Details |
| US3701851A | Switching voice and data communications simultaneously over… | Expired / Lapsed | 1970-12-09 | 1972-10-31 | 17 | Details |
| US3700815A | Automatic speaker verification by non-linear time alignment… | Expired / Lapsed | 1971-04-20 | 1972-10-24 | 17 | Details |
| US3701130A | Memory access system | Expired / Lapsed | 1971-02-10 | 1972-10-24 | 18 | Details |
| US3701109A | Priority access system | Expired / Lapsed | 1970-11-09 | 1972-10-24 | 18 | Details |
| US3700890A | Measurement of gas impurity concentration by infrared absor… | Expired / Lapsed | 1970-11-02 | 1972-10-24 | 11 | Details |
| US3698816A | Laser guidance system | Expired / Lapsed | 1970-09-16 | 1972-10-17 | 2 | Details |
| US3696985A | Methods of and apparatus for aligning and bonding workpieces | Expired / Lapsed | 1969-12-31 | 1972-10-10 | 29 | Details |
| US3696310A | Mode-locking in semiconductor lasers | Expired / Lapsed | 1970-10-01 | 1972-10-03 | 23 | Details |
| US3694055A | Thin film, biaxially birefringent nonlinear devices | Expired / Lapsed | 1971-03-12 | 1972-09-26 | 12 | Details |
| US3693153A | Parity check apparatus and method for minicomputers | Expired / Lapsed | 1971-07-09 | 1972-09-19 | 39 | Details |
| US3692942A | Multiplexed information transmission system | Expired / Lapsed | 1971-06-07 | 1972-09-19 | 38 | Details |
| US3688097A | Digital attenuator for non-linear pulse code modulation sig… | Expired / Lapsed | 1970-05-20 | 1972-08-29 | 20 | Details |
| US3683418A | Method of protecting data in a multiprocessor computer syst… | Expired / Lapsed | 1970-04-16 | 1972-08-08 | 30 | Details |
| US3679832A | Three-channel fm stereo transmission | Expired / Lapsed | 1971-03-23 | 1972-07-25 | 14 | Details |
| US3680056A | Use equalization on closed loop message block transmission … | Expired / Lapsed | 1970-10-08 | 1972-07-25 | 13 | Details |
| US3679977A | Precoded ternary data transmission | Expired / Lapsed | 1969-06-24 | 1972-07-25 | 10 | Details |
| US3678467A | Multiprocessor with cooperative program execution | Expired / Lapsed | 1970-10-20 | 1972-07-18 | 21 | Details |
| US3678464A | Controlled pause and restart of magnetic disc memories and … | Expired / Lapsed | 1970-06-29 | 1972-07-18 | 14 | Details |
| US3675985A | Optical autocorrelator for autocorrelating picosecond optic… | Expired / Lapsed | 1970-08-03 | 1972-07-11 | 0 | Details |
| US3674337A | Beam coupling to and from thin film waveguide | Expired / Lapsed | 1970-12-07 | 1972-07-04 | 0 | Details |
| US3673357A | Tactile response switch with unitary control strip of indep… | Expired / Lapsed | 1971-03-29 | 1972-06-27 | 8 | Details |
| US3673335A | Switching of time division multiplex lines and analog trunk… | Expired / Lapsed | 1970-08-24 | 1972-06-27 | 11 | Details |
| US3670209A | Pulse generator comprising serially connected make and brea… | Expired / Lapsed | 1971-05-03 | 1972-06-13 | 8 | Details |
| US3666348A | Multimode waveguide | Expired / Lapsed | 1970-09-25 | 1972-05-30 | 0 | Details |
| US3665171A | Nonrecursive digital filter apparatus employing delayedadd … | Expired / Lapsed | 1970-12-14 | 1972-05-23 | 16 | Details |
| US3663762A | Mobile communication system | Expired / Lapsed | 1970-12-21 | 1972-05-16 | 23 | Details |
| US3662268A | Diversity communication system using distinct spectral arra… | Expired / Lapsed | 1970-11-17 | 1972-05-09 | 20 | Details |
| US3657003A | Method of rendering a non-wettable surface wettable | Expired / Lapsed | 1970-02-02 | 1972-04-18 | 23 | Details |
| US3655920A | Electrical communication switching network | Expired / Lapsed | 1970-11-16 | 1972-04-11 | 22 | Details |
| US3655261A | Deflection of electromagnetic beams from guides by acoustic… | Expired / Lapsed | 1970-03-02 | 1972-04-11 | 2 | Details |
| US3656161A | Maintaining a circularly polarized magnetic field at a movi… | Expired / Lapsed | 1969-12-31 | 1972-04-11 | 6 | Details |
| US3654499A | Charge coupled memory with storage sites | Expired / Lapsed | 1970-06-24 | 1972-04-04 | 37 | Details |
| US3654476A | Solid-state television camera devices | Expired / Lapsed | 1969-10-24 | 1972-04-04 | 8 | Details |
| US3652993A | Rapid polling method for digital communications network | Expired / Lapsed | 1970-07-24 | 1972-03-28 | 13 | Details |
| US3651509A | Light pen for display having inherent memory | Expired / Lapsed | 1970-11-06 | 1972-03-21 | 14 | Details |
| US3650454A | Device for bonding with a compliant medium | Expired / Lapsed | 1969-11-21 | 1972-03-21 | 23 | Details |
| US3647406A | Method of achieving surface refractive index changes in a g… | Expired / Lapsed | 1968-11-04 | 1972-03-07 | 2 | Details |
| US3647538A | Magnetic element using isolated domains in rare earth ortho… | Expired / Lapsed | 1968-02-05 | 1972-03-07 | 8 | Details |
| US3646518A | Feedback error control system | Expired / Lapsed | 1970-05-05 | 1972-02-29 | 25 | Details |
| US3634614A | Infrared-energized visual displays using up-converting phos… | Expired / Lapsed | 1969-04-16 | 1972-01-11 | 17 | Details |
| US3630596A | Photomask regeneration by intensity spatial filtering | Expired / Lapsed | 1969-09-30 | 1971-12-28 | 9 | Details |
| US3631520A | Predictive coding of speech signals | Expired / Lapsed | 1968-08-19 | 1971-12-28 | 16 | Details |
| US3629842A | Multiple memory-accessing system | Expired / Lapsed | 1970-04-30 | 1971-12-21 | 25 | Details |
| US3627930A | Dial-in-handset telephone assembly | Expired / Lapsed | 1969-10-27 | 1971-12-14 | 3 | Details |
| US3623019A | Programmed time-out monitoring arrangement using map timing | Expired / Lapsed | 1969-11-26 | 1971-11-23 | 15 | Details |
| US3623011A | Time-shared access to computer registers | Expired / Lapsed | 1969-06-25 | 1971-11-23 | 33 | Details |
| US3616406A | Preparation of glue layer for bonding gold to a substrate | Expired / Lapsed | 1969-11-03 | 1971-10-26 | 3 | Details |
| US3614198A | Thin-film optical devices | Expired / Lapsed | 1969-06-23 | 1971-10-19 | 18 | Details |
| US3609244A | Conditional replenishment video system with variable length… | Expired / Lapsed | 1969-12-18 | 1971-09-28 | 21 | Details |
| US3609704A | Memory maintenance arrangement for recognizing and isolatin… | Expired / Lapsed | 1969-10-06 | 1971-09-28 | 47 | Details |
| US3607699A | Technique for the deposition of gallium phosphide resistive… | Expired / Lapsed | 1969-08-08 | 1971-09-21 | 4 | Details |
| US3604986A | High frequency transistors with shallow emitters | Expired / Lapsed | 1970-03-17 | 1971-09-14 | 8 | Details |
| US3605091A | Feedback error control arrangement | Expired / Lapsed | 1969-09-18 | 1971-09-14 | 24 | Details |
| US3605046A | Deflection-free waveguide arrangement | Expired / Lapsed | 1969-03-12 | 1971-09-14 | 5 | Details |
| US3603739A | Digital transmission system employing identifiable marker s… | Expired / Lapsed | 1969-12-17 | 1971-09-07 | 5 | Details |
| US3598915A | Measurement of maximum of a series of time intervals | Expired / Lapsed | 1969-11-24 | 1971-08-10 | 17 | Details |
| US3594560A | Digital expandor circuit | Expired / Lapsed | 1969-01-03 | 1971-07-20 | 6 | Details |
| US3589794A | Optical circuits | Expired / Lapsed | 1968-08-07 | 1971-06-29 | 22 | Details |
| US3585635A | Analog-to-digital converter | Expired / Lapsed | 1968-12-23 | 1971-06-15 | 15 | Details |
| US3584782A | Fast fourier transform method and apparatus | Expired / Lapsed | 1968-07-01 | 1971-06-15 | 67 | Details |
| US3582943A | High-speed digital-to-analog converter | Expired / Lapsed | 1968-12-09 | 1971-06-01 | 12 | Details |
| US3573381A | Time division switching system | Expired / Lapsed | 1969-03-26 | 1971-04-06 | 26 | Details |
| US3573745A | Group queuing | Expired / Lapsed | 1968-12-04 | 1971-04-06 | 17 | Details |
| US3571737A | Transmission line | Expired / Lapsed | 1968-06-07 | 1971-03-23 | 12 | Details |
| US3571794A | Automatic synchronization recovery for data systems utilizi… | Expired / Lapsed | 1967-09-27 | 1971-03-23 | 23 | Details |
| US3569996A | Optical heterodyne receiver with pulse widening or stretchi… | Expired / Lapsed | 1968-06-07 | 1971-03-09 | 11 | Details |
| US3562005A | Method of generating precious metal-reducing patterns | Expired / Lapsed | 1968-04-09 | 1971-02-09 | 0 | Details |
| US3558366A | Metal shielding for ion implanted semiconductor device | Expired / Lapsed | 1968-09-17 | 1971-01-26 | 0 | Details |
| US3555335A | Electroluminescent displays | Expired / Lapsed | 1969-02-27 | 1971-01-12 | 10 | Details |
| US3555181A | Automatic video level control employing iris and amplifier … | Expired / Lapsed | 1968-06-05 | 1971-01-12 | 7 | Details |
| US3553361A | Conditional replenishment video system with sample grouping | Expired / Lapsed | 1969-04-30 | 1971-01-05 | 10 | Details |
| US3553606A | System for providing adjusting signals to a transversal fil… | Expired / Lapsed | 1969-04-21 | 1971-01-05 | 0 | Details |
| US3553541A | Bilateral switch using combination of field effect transist… | Expired / Lapsed | 1969-04-17 | 1971-01-05 | 0 | Details |
| US3553654A | Fault isolation arrangement for distributed logic memories | Expired / Lapsed | 1969-03-28 | 1971-01-05 | 0 | Details |
| US3543243A | Data receiving arrangement | Expired / Lapsed | 1967-09-13 | 1970-11-24 | 0 | Details |
| US3540019A | Single wall domain device | Expired / Lapsed | 1968-03-04 | 1970-11-10 | 0 | Details |
| US3539992A | Missing character detector | Expired / Lapsed | 1968-01-18 | 1970-11-10 | 0 | Details |
| US3539997A | Synchronizing circuit | Expired / Lapsed | 1962-12-05 | 1970-11-10 | 2 | Details |
| US3536838A | Amplifier with voice- and line-switched gain controls in ne… | Expired / Lapsed | 1968-10-01 | 1970-10-27 | 0 | Details |
| US3537027A | Frequency-stabilized single mode ring lasers | Expired / Lapsed | 1967-07-27 | 1970-10-27 | 0 | Details |
| US3535633A | Systems for detecting discontinuity in selected wiring circ… | Expired / Lapsed | 1967-06-21 | 1970-10-20 | 0 | Details |
| US3533676A | Hyperstereoscopic and hypostereoscopic image generation | Expired / Lapsed | 1968-04-24 | 1970-10-13 | 0 | Details |
| US3534338A | Computer graphics system | Expired / Lapsed | 1967-11-13 | 1970-10-13 | 0 | Details |
| US3531597A | Telephone reporting set | Expired / Lapsed | 1967-02-06 | 1970-09-29 | 0 | Details |
| US3529682A | Location detection and guidance systems for burrowing device | Expired / Lapsed | 1968-10-03 | 1970-09-22 | 0 | Details |
| US3529089A | Distributed subscriber carrier-concentrator system | Expired / Lapsed | 1968-08-28 | 1970-09-15 | 0 | Details |
| US3527958A | Ultrasonic delay line memory | Expired / Lapsed | 1968-02-16 | 1970-09-08 | 0 | Details |
| US3521070A | Optical gate | Expired / Lapsed | 1967-11-24 | 1970-07-21 | 0 | Details |
| US3520055A | Method for holding workpieces for radiant energy bonding | Expired / Lapsed | 1967-04-26 | 1970-07-14 | 0 | Details |
| US3516731A | Beam focusing by acoustic waves | Expired / Lapsed | 1968-05-27 | 1970-06-23 | 0 | Details |
| US3517123A | Scanner control means for a stored program controlled switc… | Expired / Lapsed | 1967-11-24 | 1970-06-23 | 0 | Details |
| US3515815A | Resistance controlled pulse generator | Expired / Lapsed | 1968-02-05 | 1970-06-02 | 0 | Details |
| US3508730A | Cable securing clip | Expired / Lapsed | 1967-12-20 | 1970-04-28 | 0 | Details |
| US3506932A | Quadrature hybrid coupler | Expired / Lapsed | 1968-02-28 | 1970-04-14 | 0 | Details |
| US3506331A | Optical waveguide | Expired / Lapsed | 1967-10-03 | 1970-04-14 | 0 | Details |
| US3506834A | Time-division multiplex optical transmission system | Expired / Lapsed | 1967-04-17 | 1970-04-14 | 0 | Details |
| US3506779A | Laser beam typesetter | Expired / Lapsed | 1967-04-03 | 1970-04-14 | 0 | Details |
| US3502986A | Adaptive prediction for redundancy removal in data transmis… | Expired / Lapsed | 1967-12-14 | 1970-03-24 | 0 | Details |
| US3503054A | Domain wall propagation in magnetic shefts | Expired / Lapsed | 1967-10-12 | 1970-03-24 | 0 | Details |
| US3501826A | Apparatus for assembling a pair of articles one within the … | Expired / Lapsed | 1967-04-21 | 1970-03-24 | 0 | Details |
| US3501587A | In-line holographic arrangement for imaging a person viewin… | Expired / Lapsed | 1966-12-21 | 1970-03-17 | 0 | Details |
| US3500441A | Delta modulation with discrete companding | Expired / Lapsed | 1967-10-12 | 1970-03-10 | 0 | Details |
| US3495894A | Optical beam deflection utilizing linbo3 or litao3 | Expired / Lapsed | 1965-12-28 | 1970-02-17 | 0 | Details |
| US3495220A | Process control system including hardware element status ma… | Expired / Lapsed | 1967-05-15 | 1970-02-10 | 0 | Details |
| US3493894A | Amplitude and phase-locking of laser transitions by self-dr… | Expired / Lapsed | 1967-08-21 | 1970-02-03 | 0 | Details |
| US3492440A | Direct station selection telephone set employing proximity … | Expired / Lapsed | 1967-05-25 | 1970-01-27 | 0 | Details |
| US3492432A | Pulse amplitude modulation multiplex video transmission sys… | Expired / Lapsed | 1967-03-08 | 1970-01-27 | 0 | Details |
| US3492645A | Monitoring circuit for line unit scanned on a time shared b… | Expired / Lapsed | 1966-11-02 | 1970-01-27 | 0 | Details |
| US3492571A | Apparatus for testing an electrical circuit for opens,short… | Expired / Lapsed | 1965-12-02 | 1970-01-27 | 0 | Details |
| US3488440A | Timing wave recovery circuit for synchronous data repeater | Expired / Lapsed | 1966-12-28 | 1970-01-06 | 0 | Details |
| US3484147A | Hologram storage apparatus and method using a diffusing med… | Expired / Lapsed | 1966-08-11 | 1969-12-16 | 0 | Details |
| US3480917A | Arrangement for transferring between program sequences in a… | Expired / Lapsed | 1967-06-01 | 1969-11-25 | 0 | Details |
| US3477043A | Automatic d.c. offset compensation circuit for automatic eq… | Expired / Lapsed | 1968-01-24 | 1969-11-04 | 0 | Details |
| US3475736A | Lamellate optically responsive memory arrangement | Expired / Lapsed | 1965-12-23 | 1969-10-28 | 0 | Details |
| US3475733A | Information storage system | Expired / Lapsed | 1964-07-21 | 1969-10-28 | 0 | Details |
| US3471648A | Vocoder utilizing companding to reduce background noise cau… | Expired / Lapsed | 1966-07-28 | 1969-10-07 | 0 | Details |
| US3471686A | Error detection system for synchronized duplicate data proc… | Expired / Lapsed | 1966-01-03 | 1969-10-07 | 0 | Details |
| US3466441A | Semiconductor infrared-to-visible light image converter | Expired / Lapsed | 1967-04-07 | 1969-09-09 | 0 | Details |
| US3466566A | Optical resonator for lasers | Expired / Lapsed | 1966-02-17 | 1969-09-09 | 0 | Details |
| US3464762A | Optical wave modulator | Expired / Lapsed | 1965-12-16 | 1969-09-02 | 0 | Details |
| US3462603A | Acoustic licht modulator and variable delay device | Expired / Lapsed | 1966-05-02 | 1969-08-19 | 0 | Details |
| US3462557A | Intra-concentrator call detecting circuit | Expired / Lapsed | 1965-12-27 | 1969-08-19 | 0 | Details |
| US3461244A | Delta modulation system with continuously variable compander | Expired / Lapsed | 1966-08-16 | 1969-08-12 | 0 | Details |
| US3460116A | Magnetic domain propagation circuit | Expired / Lapsed | 1966-09-16 | 1969-08-05 | 0 | Details |
| US3458661A | Arrangement for providing partial service on a failed seria… | Expired / Lapsed | 1966-06-21 | 1969-07-29 | 0 | Details |
| US3452330A | Asynchronous data transmission system with error detection … | Expired / Lapsed | 1967-07-25 | 1969-06-24 | 0 | Details |
| US3449577A | Controlled transmission of waves through inhomogeneous media | Expired / Lapsed | 1965-10-23 | 1969-06-10 | 0 | Details |
| US3447036A | Assembly for mounting and aligning modules | Expired / Lapsed | 1967-04-21 | 1969-05-27 | 0 | Details |
| US3446917A | Time division switching system | Expired / Lapsed | 1965-06-07 | 1969-05-27 | 0 | Details |
| US3442432A | Bonding a beam-leaded device to a substrate | Expired / Lapsed | 1967-06-15 | 1969-05-06 | 0 | Details |
| US3443210A | Test circuit for evaluating magnetic memory devices | Expired / Lapsed | 1964-08-26 | 1969-05-06 | 0 | Details |
| US3441747A | Detector for bipolar digital signals | Expired / Lapsed | 1965-12-13 | 1969-04-29 | 0 | Details |
| US3440618A | Information processing system | Expired / Lapsed | 1967-07-07 | 1969-04-22 | 0 | Details |
| US3440351A | Telephone transmitter circuit employing variable capacitanc… | Expired / Lapsed | 1966-09-09 | 1969-04-22 | 0 | Details |
| US3438873A | Anodic treatment to alter solubility of dielectric films | Expired / Lapsed | 1966-05-11 | 1969-04-15 | 0 | Details |
| US3439340A | Sequential access memory system | Expired / Lapsed | 1965-07-30 | 1969-04-15 | 0 | Details |
| US3439169A | Tunable solid state laser | Expired / Lapsed | 1965-02-11 | 1969-04-15 | 0 | Details |
| US3437757A | Speech analysis system | Expired / Lapsed | 1966-06-15 | 1969-04-08 | 0 | Details |
| US3437927A | Peak detection system for arbitrary portions of repetitive … | Expired / Lapsed | 1966-02-02 | 1969-04-08 | 0 | Details |
| US3436486A | Error detection system | Expired / Lapsed | 1965-12-21 | 1969-04-01 | 0 | Details |
| US3435159A | Circuit and method for testing complex systems | Expired / Lapsed | 1966-01-03 | 1969-03-25 | 0 | Details |
| US3434774A | Waveguide for millimeter and optical waves | Expired / Lapsed | 1965-02-02 | 1969-03-25 | 0 | Details |
| US3434056A | Distortion monitoring by comparing square and cubic law dis… | Expired / Lapsed | 1966-05-31 | 1969-03-18 | 0 | Details |
| US3427589A | On-line delivery of data messages from a transmitter to rec… | Expired / Lapsed | 1967-06-29 | 1969-02-11 | 0 | Details |
| US3427588A | Distribution of messages to data station receivers on multi… | Expired / Lapsed | 1967-06-29 | 1969-02-11 | 0 | Details |
| US3427403A | Automatic reporting telephone with message transmission res… | Expired / Lapsed | 1964-12-22 | 1969-02-11 | 0 | Details |
| US3426218A | Pulse generator employing two sequentially gated monostable… | Expired / Lapsed | 1966-04-08 | 1969-02-04 | 0 | Details |
| US3426153A | System for synchronizing digital communication apparatus | Expired / Lapsed | 1963-12-18 | 1969-02-04 | 0 | Details |
| US3424934A | Electroluminescent cell comprising zinc-doped gallium arsen… | Expired / Lapsed | 1966-08-10 | 1969-01-28 | 0 | Details |
| US3424532A | Angle-lap techniques for measuring layer thicknesses | Expired / Lapsed | 1964-12-29 | 1969-01-28 | 2 | Details |
| US3423538A | Telephone conference circuit | Expired / Lapsed | 1964-12-28 | 1969-01-21 | 0 | Details |
| US3423534A | Transmission of supervisory information | Expired / Lapsed | 1963-11-21 | 1969-01-21 | 4 | Details |
| US3414845A | Automatic equalizer for digital transmission systems utiliz… | Expired / Lapsed | 1965-09-28 | 1968-12-03 | 0 | Details |
| US3414814A | Method of and apparatus for testing cross section and conti… | Expired / Lapsed | 1964-12-31 | 1968-12-03 | 0 | Details |
| US3413449A | Rate registering circuit | Expired / Lapsed | 1965-04-26 | 1968-11-26 | 0 | Details |
| US3412251A | Mode locking in a synchronously modulated maser | Expired / Lapsed | 1964-04-24 | 1968-11-19 | 0 | Details |
| US3409848A | Elastic surface waveguide | Expired / Lapsed | 1967-10-30 | 1968-11-05 | 0 | Details |
| US3409879A | Computer organization employing plural operand storage | Expired / Lapsed | 1966-03-30 | 1968-11-05 | 0 | Details |
| US3406256A | Coin telephone emergency service | Expired / Lapsed | 1965-06-02 | 1968-10-15 | 0 | Details |
| US3406043A | Integrated circuit containing multilayer tantalum compounds | Expired / Lapsed | 1964-11-09 | 1968-10-15 | 0 | Details |
| US3405371A | Fluorescent garnet compositions and optical maser devices u… | Expired / Lapsed | 1966-04-01 | 1968-10-08 | 2 | Details |
| US3404349A | Optical maser for higher order modes | Expired / Lapsed | 1964-04-28 | 1968-10-01 | 0 | Details |
| US3403284A | Target structure storage device using diode array | Expired / Lapsed | 1966-12-29 | 1968-09-24 | 2 | Details |
| US3403340A | Automatic mean-square equalizer | Expired / Lapsed | 1966-11-21 | 1968-09-24 | 2 | Details |
| US3403226A | Reduced bandwidth dual mode encoding of video signals | Expired / Lapsed | 1965-09-30 | 1968-09-24 | 0 | Details |
| US3403383A | Integrated analog-digital switching system with modular mes… | Expired / Lapsed | 1964-05-28 | 1968-09-24 | 0 | Details |
| US3401359A | Transistor switching modulators and demodulators | Expired / Lapsed | 1966-03-04 | 1968-09-10 | 2 | Details |
| US3401379A | False code generator | Expired / Lapsed | 1966-01-10 | 1968-09-10 | 0 | Details |
| US3400341A | Elastic dispersive delay line | Expired / Lapsed | 1966-03-08 | 1968-09-03 | 2 | Details |
| US3399385A | Activity reporting system | Expired / Lapsed | 1965-12-07 | 1968-08-27 | 0 | Details |
| US3395396A | Information-dependent signal shifting for data processing s… | Expired / Lapsed | 1965-11-23 | 1968-07-30 | 0 | Details |
| US3395365A | Frequency stabilized optical maser | Expired / Lapsed | 1965-02-24 | 1968-07-30 | 0 | Details |
| US3394355A | Information storage timing arrangement | Expired / Lapsed | 1966-04-15 | 1968-07-23 | 2 | Details |
| US3394268A | Logic switching circuit | Expired / Lapsed | 1965-02-01 | 1968-07-23 | 1 | Details |
| US3391390A | Information storage and processing system utilizing associa… | Expired / Lapsed | 1964-09-09 | 1968-07-02 | 0 | Details |
| US3387278A | Data processor with simultaneous testing and indexing on co… | Expired / Lapsed | 1965-10-20 | 1968-06-04 | 0 | Details |
| US3386043A | Dielectric waveguide, maser amplifier and oscillator | Expired / Lapsed | 1964-07-31 | 1968-05-28 | 0 | Details |
| US3384814A | Ridge waveguide resonant cavity for measuring dielectric co… | Expired / Lapsed | 1963-09-25 | 1968-05-21 | 2 | Details |
| US3383664A | Electro-optical storage arrangement | Expired / Lapsed | 1967-03-31 | 1968-05-14 | 0 | Details |
| US3382022A | Lens guided optical transmission path with diffraction corr… | Expired / Lapsed | 1964-10-12 | 1968-05-07 | 0 | Details |
| US3378845A | Generation of beacon signals for communication satellite | Expired / Lapsed | 1965-04-13 | 1968-04-16 | 0 | Details |
| US3376555A | Two-dimensional associative memory system | Expired / Lapsed | 1965-06-18 | 1968-04-02 | 0 | Details |
| US3375408A | Test fixture for keyed printed circuit board | Expired / Lapsed | 1965-11-15 | 1968-03-26 | 0 | Details |
| US3375473A | Automatic equalizer for analog channels having means for co… | Expired / Lapsed | 1965-07-15 | 1968-03-26 | 2 | Details |
| US3374531A | Method of soldering with radiant energy | Expired / Lapsed | 1965-04-21 | 1968-03-26 | 0 | Details |
| US3374435A | Reduction of the effect of impulse noise bursts | Expired / Lapsed | 1965-07-29 | 1968-03-19 | 1 | Details |
| US3374413A | System for maintaining a motor at a predetermined speed | Expired / Lapsed | 1965-05-06 | 1968-03-19 | 0 | Details |
| US3374463A | Shift and rotate circuit for a data processor | Expired / Lapsed | 1964-12-23 | 1968-03-19 | 0 | Details |
| US3372244A | Semiconductive transducers | Expired / Lapsed | 1966-07-07 | 1968-03-05 | 0 | Details |
| US3371220A | Optical parametric device using third-order nonlinearity | Expired / Lapsed | 1966-10-25 | 1968-02-27 | 0 | Details |
| US3370274A | Data processor control utilizing tandem signal operations | Expired / Lapsed | 1964-12-30 | 1968-02-20 | 0 | Details |
| US3370270A | Information checking system | Expired / Lapsed | 1963-04-10 | 1968-02-20 | 2 | Details |
| US3369229A | Multilevel pulse transmission system | Expired / Lapsed | 1964-12-14 | 1968-02-13 | 0 | Details |
| US3368168A | Adaptive equalizer for digital transmission systems having … | Expired / Lapsed | 1965-06-02 | 1968-02-06 | 2 | Details |
| US3366931A | Information storage system | Expired / Lapsed | 1965-03-23 | 1968-01-30 | 0 | Details |
| US3366778A | Pulse register circuit | Expired / Lapsed | 1964-11-16 | 1968-01-30 | 2 | Details |
| US3365581A | Optical modulators | Expired / Lapsed | — | 1968-01-23 | 0 | Details |
| US3364433A | Molecular swarm liquid crystal optical parametric devices | Expired / Lapsed | 1967-03-10 | 1968-01-16 | 0 | Details |
| US3363063A | Circuit arrangement which enables subscriber controlled spe… | Expired / Lapsed | 1964-12-24 | 1968-01-09 | 2 | Details |
| US3360610A | Bandwidth compression utilizing magnitude and phase coded s… | Expired / Lapsed | 1964-05-07 | 1967-12-26 | 2 | Details |
| US3359369A | Systems for processing data over telephone networks | Expired / Lapsed | 1964-02-26 | 1967-12-19 | 2 | Details |
| US3355579A | Correlation apparatus | Expired / Lapsed | 1965-10-20 | 1967-11-28 | 2 | Details |
| US3355556A | Automatic mobile radio telephone switching system | Expired / Lapsed | 1964-05-18 | 1967-11-28 | 2 | Details |
| US3354260A | Through-connectors for circuit boards and method of applyin… | Expired / Lapsed | 1966-07-18 | 1967-11-21 | 2 | Details |
| US3354005A | Methods of applying doping compositions to base materials | Expired / Lapsed | 1965-10-23 | 1967-11-21 | 2 | Details |
| US3354267A | Differential pcm system employing digital integration | Expired / Lapsed | 1965-01-13 | 1967-11-21 | 2 | Details |
| US3351868A | Phase locked loop with fast frequency pull-in | Expired / Lapsed | 1966-02-02 | 1967-11-07 | 2 | Details |
| US3349403A | Ground station antenna pointing system for satellite commun… | Expired / Lapsed | 1965-04-29 | 1967-10-24 | 2 | Details |
| US3349191A | Talk-off protection for in-band telephone signaling systems | Expired / Lapsed | 1965-01-07 | 1967-10-24 | 2 | Details |
| US3348211A | Return address system for a data processor | Expired / Lapsed | 1964-12-10 | 1967-10-17 | 2 | Details |
| US3348210A | Digital computer employing plural processors | Expired / Lapsed | 1964-12-07 | 1967-10-17 | 2 | Details |
| US3346067A | System for determining acoustic reflection coefficients | Expired / Lapsed | 1966-03-16 | 1967-10-10 | 2 | Details |
| US3344349A | Apparatus for analyzing the spectra of complex waves | Expired / Lapsed | 1963-10-07 | 1967-09-26 | 0 | Details |
| US3342934A | Private branch exchange telephone system with dial transfer… | Expired / Lapsed | 1964-09-02 | 1967-09-19 | 2 | Details |
| US3340514A | Delay line assembler of data characters | Expired / Lapsed | 1964-10-21 | 1967-09-05 | 2 | Details |
| US3335229A | Arrangement for controlling traffic in a switching network | Expired / Lapsed | 1963-11-05 | 1967-08-08 | 2 | Details |
| US3334959A | Adjustable optical device | Expired / Lapsed | 1963-10-17 | 1967-08-08 | 2 | Details |
| US3334183A | Teletypewriter receiver for receiving data asynchronously o… | Expired / Lapsed | 1963-10-24 | 1967-08-01 | 2 | Details |
| US3330909A | Pulse communication system | Expired / Lapsed | 1964-01-02 | 1967-07-11 | 2 | Details |
| US3331030A | Automatic gain control circuit | Expired / Lapsed | 1963-08-20 | 1967-07-11 | 2 | Details |
| US3328723A | Optical frequency parametric oscillators and modulators wit… | Expired / Lapsed | 1965-12-23 | 1967-06-27 | 2 | Details |
| US3328528A | Apparatus for interchanging time and frequency signals | Expired / Lapsed | 1963-11-04 | 1967-06-27 | 2 | Details |
| US3322902A | Telephone subscriber's line circuit | Expired / Lapsed | 1963-12-23 | 1967-05-30 | 2 | Details |
| US3322026A | Attenuation measuring device using an optical maser | Expired / Lapsed | 1963-10-21 | 1967-05-30 | 2 | Details |
| US3315171A | Digitalized transversal filter | Expired / Lapsed | 1963-12-24 | 1967-04-18 | 1 | Details |
| US3315039A | Telephone signaling conversion circuit for pulses and tones | Expired / Lapsed | 1963-09-30 | 1967-04-18 | 2 | Details |
| US3315232A | Resonant circuit timed translator matrix employing transist… | Expired / Lapsed | 1962-05-16 | 1967-04-18 | 2 | Details |
| US3312947A | Plural memory system with internal memory transfer and dupl… | Expired / Lapsed | 1963-12-31 | 1967-04-04 | 1 | Details |
| US3311890A | Apparatus for testing a storage system | Expired / Lapsed | 1963-08-20 | 1967-03-28 | 2 | Details |
| US3308243A | Establishing intraconcentrator connections in a remote line… | Expired / Lapsed | 1963-12-16 | 1967-03-07 | 2 | Details |
| US3294670A | Apparatus for processing materials in a controlled atmosphe… | Expired / Lapsed | 1963-10-07 | 1966-12-27 | 4 | Details |
| US3295117A | Position sensing apparatus | Expired / Lapsed | 1963-03-21 | 1966-12-27 | 2 | Details |
| US3295064A | Ultrasonic pulse modifier | Expired / Lapsed | 1962-06-20 | 1966-12-27 | 1 | Details |
| US3292110A | Transversal equalizer for digital transmission systems wher… | Expired / Lapsed | 1964-09-16 | 1966-12-13 | 2 | Details |
| US3290753A | Method of making semiconductor integrated circuit elements | Expired / Lapsed | 1963-08-19 | 1966-12-13 | 2 | Details |
| US3291913A | Telephone system signal converter | Expired / Lapsed | 1963-05-17 | 1966-12-13 | 2 | Details |
| US3289014A | Digital time compressor with self-biased threshold | Expired / Lapsed | 1965-12-16 | 1966-11-29 | 1 | Details |
| US3289114A | Tapped ultrasonic delay line and uses therefor | Expired / Lapsed | 1963-12-24 | 1966-11-29 | 2 | Details |
| US3289100A | Niobate maser materials and devices made therefrom | Expired / Lapsed | 1963-04-25 | 1966-11-29 | 2 | Details |
| US3287243A | Deposition of insulating films by cathode sputtering in an … | Expired / Lapsed | 1965-03-29 | 1966-11-22 | 2 | Details |
| US3284779A | Associative memory including means for retrieving one of a … | Expired / Lapsed | 1963-04-09 | 1966-11-08 | 2 | Details |
| US3283131A | Digital signal generator | Expired / Lapsed | 1963-09-25 | 1966-11-01 | 1 | Details |
| US3283307A | Detection of erroneous data processing transfers | Expired / Lapsed | 1963-01-03 | 1966-11-01 | 2 | Details |
| US3281539A | Control system for communication switching systems | Expired / Lapsed | 1963-07-16 | 1966-10-25 | 2 | Details |
| US3277404A | Ultrasonic delay device | Expired / Lapsed | 1963-08-23 | 1966-10-04 | 0 | Details |
| US3277225A | Methods and apparatus for multiple extrusion of plastics | Expired / Lapsed | 1963-02-13 | 1966-10-04 | 2 | Details |
| US3274670A | Semiconductor contact | Expired / Lapsed | 1965-03-18 | 1966-09-27 | 2 | Details |
| US3274511A | Frequency stabilized sweep frequency generator | Expired / Lapsed | 1963-12-30 | 1966-09-20 | 1 | Details |
| US3273151A | Antenna system | Expired / Lapsed | 1961-12-26 | 1966-09-13 | 1 | Details |
| US3271703A | Transversal filter | Expired / Lapsed | 1962-12-21 | 1966-09-06 | 1 | Details |
| US3267804A | Optical circulator | Expired / Lapsed | 1963-01-03 | 1966-08-23 | 2 | Details |
| US3266018A | Telemetering system for reading remotely loacted utility me… | Expired / Lapsed | 1962-10-04 | 1966-08-09 | 2 | Details |
| US3257628A | Resetting circuitry for a square-loop ferromagnetic core ut… | Expired / Lapsed | 1963-05-21 | 1966-06-21 | 1 | Details |
| US3254342A | Antenna system wherein beamwidth variation is achieved by c… | Expired / Lapsed | 1963-07-09 | 1966-05-31 | 2 | Details |
| US3252183A | Channelled extrusion die | Expired / Lapsed | 1964-01-08 | 1966-05-24 | 2 | Details |
| US3253220A | Test apparatus including balanced transformers for detectin… | Expired / Lapsed | 1961-10-06 | 1966-05-24 | 1 | Details |
| US3253259A | Plural channel data transmission system having means for ut… | Expired / Lapsed | 1961-09-19 | 1966-05-24 | 2 | Details |
| US3253134A | Digit by digit series high-low limit comparator having mean… | Expired / Lapsed | 1961-03-15 | 1966-05-24 | 2 | Details |
| US3252007A | Stabilized non-linear feedback amplifier | Expired / Lapsed | 1963-10-03 | 1966-05-17 | 2 | Details |
| US3249221A | Apparatus for securing threaded members and for detecting i… | Expired / Lapsed | 1964-06-22 | 1966-05-03 | 2 | Details |
| US3245314A | Optical rotation devices employing a ferromagnetic chromium… | Expired / Lapsed | 1962-06-28 | 1966-04-12 | 2 | Details |
| US3246328A | Precision radar system | Expired / Lapsed | 1961-12-07 | 1966-04-12 | 2 | Details |
| US3245040A | Data receiving circuit | Expired / Lapsed | 1958-04-21 | 1966-04-05 | 2 | Details |
| US3243699A | Measuring set with compensation for standard attenuator cal… | Expired / Lapsed | 1961-05-05 | 1966-03-29 | 2 | Details |
| US3242470A | Automation of telephone information service | Expired / Lapsed | 1962-08-21 | 1966-03-22 | 2 | Details |
| US3242439A | Visible output gaseous optical maser with mode pattern sele… | Expired / Lapsed | 1962-06-21 | 1966-03-22 | 1 | Details |
| US3235813A | Optical maser amplifiers with optimum signal to noise ratio | Expired / Lapsed | 1963-06-25 | 1966-02-15 | 1 | Details |
| US3235428A | Method of making integrated semiconductor devices | Expired / Lapsed | 1963-04-10 | 1966-02-15 | 1 | Details |
| US3235746A | Nonsaturating transistor switching circuit | Expired / Lapsed | 1960-10-11 | 1966-02-15 | 2 | Details |
| US3234482A | Stabilized ultrasonic amplifier | Expired / Lapsed | 1963-04-23 | 1966-02-08 | 2 | Details |
| US3234337A | Aid for blind switchboard attendant | Expired / Lapsed | 1962-07-20 | 1966-02-08 | 2 | Details |
| US3233112A | Preference circuit employing magnetic elements | Expired / Lapsed | 1960-02-04 | 1966-02-01 | 2 | Details |
| US3231866A | Traffic data processing system | Expired / Lapsed | 1961-09-08 | 1966-01-25 | 2 | Details |
| US3231819A | Intermodulation distortion correction of angle modulated tr… | Expired / Lapsed | 1961-09-07 | 1966-01-25 | 2 | Details |
| US3224330A | Optical reflecting system for redirecting energy | Expired / Lapsed | 1961-12-22 | 1965-12-21 | 2 | Details |
| US3223784A | Time division switching system | Expired / Lapsed | 1962-04-24 | 1965-12-14 | 2 | Details |
| US3223976A | Data communication system | Expired / Lapsed | 1961-05-26 | 1965-12-14 | 2 | Details |
| US3223785A | Electronic telephone switching system | Expired / Lapsed | 1959-12-30 | 1965-12-14 | 3 | Details |
| US3217212A | Semiconductor pin junction microwave limiter | Expired / Lapsed | 1961-05-26 | 1965-11-09 | 2 | Details |
| US3207904A | Electro-optical article positioning system | Expired / Lapsed | 1962-04-09 | 1965-09-21 | 2 | Details |
| US3206670A | Semiconductor devices having dielectric coatings | Expired / Lapsed | 1960-03-08 | 1965-09-14 | 2 | Details |
| US3205442A | Automatic adjustable equalizer for signal amplitude variati… | Expired / Lapsed | 1961-12-21 | 1965-09-07 | 2 | Details |
| US3202765A | Synchronization of frequency multiplex systems | Expired / Lapsed | 1961-08-23 | 1965-08-24 | 2 | Details |
| US3201849A | Method of winding helices | Expired / Lapsed | 1959-11-03 | 1965-08-24 | 2 | Details |
| US3201690A | Wave transient time interval measuring circuit with wave co… | Expired / Lapsed | 1960-03-09 | 1965-08-17 | 1 | Details |
| US3195047A | Frequency modulation communication system having automatic … | Expired / Lapsed | 1961-12-29 | 1965-07-13 | 2 | Details |
| US3194979A | Transistor switching circuit | Expired / Lapsed | 1961-09-29 | 1965-07-13 | 2 | Details |
| US3190961A | Telephone answering and recording system | Expired / Lapsed | 1961-12-21 | 1965-06-22 | 2 | Details |
| US3189973A | Method of fabricating a semiconductor device | Expired / Lapsed | 1961-11-27 | 1965-06-22 | 0 | Details |
| US3189832A | Pulse train repetition rate divider that divides by n+1/2 w… | Expired / Lapsed | 1962-09-18 | 1965-06-15 | 2 | Details |
| US3188569A | Receiver input unit-synchronizing circuit | Expired / Lapsed | 1962-12-14 | 1965-06-08 | 2 | Details |
| US3188639A | Satellite stabilization and attitude control | Expired / Lapsed | 1961-09-29 | 1965-06-08 | 2 | Details |
| US3185965A | Information storage system | Expired / Lapsed | 1962-04-30 | 1965-05-25 | 1 | Details |
| US3184742A | Balloon communication satellite | Expired / Lapsed | 1960-12-22 | 1965-05-18 | 2 | Details |
| US3182492A | Stabilized tunnel diode stress sensing devices | Expired / Lapsed | 1962-10-04 | 1965-05-11 | 2 | Details |
| US3183359A | Optical modulator employing reflection from piezolelectric-… | Expired / Lapsed | 1961-12-21 | 1965-05-11 | 2 | Details |
| US3179931A | Alarm transfer system | Expired / Lapsed | 1960-11-18 | 1965-04-20 | 2 | Details |
| US3175157A | Statistical framing of code words in a pulse code receiver | Expired / Lapsed | 1961-07-24 | 1965-03-23 | 2 | Details |
| US3175088A | Optical frequency modulation and heterodyne recovery system | Expired / Lapsed | 1961-06-22 | 1965-03-23 | 2 | Details |
| US3174044A | Light frequency modulator | Expired / Lapsed | 1961-05-09 | 1965-03-16 | 1 | Details |
| US3173130A | Memory circuit | Expired / Lapsed | 1960-08-08 | 1965-03-09 | 2 | Details |
| US3171031A | Optical maser modulators | Expired / Lapsed | 1961-07-31 | 1965-02-23 | 2 | Details |
| US3169245A | Passive repeaters for satellite communication systems | Expired / Lapsed | 1959-05-15 | 1965-02-09 | 1 | Details |
| US3166736A | Data sensing apparatus including means for replacing incorr… | Expired / Lapsed | 1960-08-25 | 1965-01-19 | 2 | Details |
| US3165725A | Protected amplifying device | Expired / Lapsed | 1960-12-28 | 1965-01-12 | 2 | Details |
| US3164728A | Magnetic switching circuit | Expired / Lapsed | 1962-03-30 | 1965-01-05 | 2 | Details |
| US3164831A | Automatic gain control circuits for directive receiving sys… | Expired / Lapsed | 1956-05-09 | 1965-01-05 | 2 | Details |
| US3163747A | Circuit for analyzing selected patterns of multiple intelli… | Expired / Lapsed | 1962-05-15 | 1964-12-29 | 2 | Details |
| US3160876A | Serial to parallel converter for data signals | Expired / Lapsed | 1963-05-28 | 1964-12-08 | 1 | Details |
| US3159707A | Gas optical maser | Expired / Lapsed | 1962-06-15 | 1964-12-01 | 2 | Details |
| US3159753A | Gate circuit having phase shift and storage means effecting… | Expired / Lapsed | 1962-06-05 | 1964-12-01 | 1 | Details |
| US3158027A | Electronic thermometer | Expired / Lapsed | 1961-07-05 | 1964-11-24 | 2 | Details |
| US3158685A | Synthesis of speech from code signals | Expired / Lapsed | 1961-05-04 | 1964-11-24 | 2 | Details |
| US3158738A | Digital-to-analog combinational converters | Expired / Lapsed | 1957-10-21 | 1964-11-24 | 2 | Details |
| US3157741A | Data transmission system | Expired / Lapsed | 1961-08-29 | 1964-11-17 | 2 | Details |
| US3156651A | Light transparent ferrimagnetic garnets | Expired / Lapsed | 1962-03-28 | 1964-11-10 | 4 | Details |
| US3155772A | Method for measuring data signal impairment | Expired / Lapsed | 1962-02-07 | 1964-11-03 | 2 | Details |
| US3155818A | Error-correcting systems | Expired / Lapsed | 1961-05-15 | 1964-11-03 | 2 | Details |
| US3153974A | Method of and device for indicating a predetermined pressur… | Expired / Lapsed | 1961-04-26 | 1964-10-27 | 2 | Details |
| US3152305A | Bipolar binary digital data vestigial sideband system | Expired / Lapsed | 1961-06-16 | 1964-10-06 | 2 | Details |
| US3149290A | Gas optical maser | Expired / Lapsed | 1960-12-28 | 1964-09-15 | 2 | Details |
| US3145341A | Correlation means for a direction finding system | Expired / Lapsed | 1961-01-03 | 1964-08-18 | 2 | Details |
| US3144617A | Optical maser with convex negative temperature medium extre… | Expired / Lapsed | 1961-12-29 | 1964-08-11 | 2 | Details |
| US3143666A | System for maintaining predetermined time relationship betw… | Expired / Lapsed | 1962-04-27 | 1964-08-04 | 2 | Details |
| US3142055A | Translator circuit | Expired / Lapsed | 1962-05-11 | 1964-07-21 | 2 | Details |
| US3141931A | Telephone answering equipment | Expired / Lapsed | 1962-01-19 | 1964-07-21 | 2 | Details |
| US3140451A | Optical maser device | Expired / Lapsed | 1960-10-25 | 1964-07-07 | 2 | Details |
| US3139615A | Three-level binary code transmission | Expired / Lapsed | 1962-07-25 | 1964-06-30 | 2 | Details |
| US3139487A | Bandwidth reduction system | Expired / Lapsed | 1960-12-27 | 1964-06-30 | 2 | Details |
| US3137834A | Piezoresistive stress gages | Expired / Lapsed | 1961-03-17 | 1964-06-16 | 2 | Details |
| US3136861A | Pcm network synchronization | Expired / Lapsed | 1962-10-18 | 1964-06-09 | 2 | Details |
| US3135945A | Information checking system utilizing odd and even digit ch… | Expired / Lapsed | 1961-12-20 | 1964-06-02 | 2 | Details |
| US3135862A | Digital target information transmission system with paralla… | Expired / Lapsed | 1953-09-29 | 1964-06-02 | 1 | Details |
| US3134962A | Serial buffer | Expired / Lapsed | 1959-06-08 | 1964-05-26 | 1 | Details |
| US3133155A | Signal converter circuit | Expired / Lapsed | 1960-09-27 | 1964-05-12 | 2 | Details |
| US3130277A | Order wire and alarm circuits | Expired / Lapsed | 1960-12-29 | 1964-04-21 | 2 | Details |
| US3129407A | Switching network control system | Expired / Lapsed | 1961-11-24 | 1964-04-14 | 2 | Details |
| US3127669A | Article feeding apparatus | Expired / Lapsed | 1961-03-14 | 1964-04-07 | 2 | Details |
| US3128449A | Error detecting and correcting system | Expired / Lapsed | 1960-06-14 | 1964-04-07 | 0 | Details |
| US3128452A | Magnetic storage circuits | Expired / Lapsed | 1959-05-22 | 1964-04-07 | 2 | Details |
| US3121255A | Apparatus for extruding plastic compounds | Expired / Lapsed | 1960-11-18 | 1964-02-18 | 1 | Details |
| US3121197A | Voice-frequency binary data transmission system with return… | Expired / Lapsed | 1960-03-08 | 1964-02-11 | 2 | Details |
| US3118979A | Electrostatic transducer | Expired / Lapsed | 1961-08-07 | 1964-01-21 | 2 | Details |
| US3118722A | Indication recording system | Expired / Lapsed | 1960-12-30 | 1964-01-21 | 2 | Details |
| US3118019A | Telephone signaling circuit | Expired / Lapsed | 1960-08-23 | 1964-01-14 | 1 | Details |
| US3118133A | Information storage matrix utilizing a dielectric of pressu… | Expired / Lapsed | 1960-04-05 | 1964-01-14 | 2 | Details |
| US3118018A | Mobile radio telephone integrated system | Expired / Lapsed | 1959-03-02 | 1964-01-14 | 2 | Details |
| US3117013A | Glass composition | Expired / Lapsed | 1961-11-06 | 1964-01-07 | 2 | Details |
| US3116443A | Semiconductor device | Expired / Lapsed | 1961-01-16 | 1963-12-31 | 2 | Details |
| US3114142A | Selective paging system | Expired / Lapsed | 1960-08-03 | 1963-12-10 | 2 | Details |
| US3113204A | Parity checked shift register counting circuits | Expired / Lapsed | 1958-03-31 | 1963-12-03 | 2 | Details |
| US3112450A | Pulse resolution circuit with gated delay means and flip-fl… | Expired / Lapsed | 1962-08-15 | 1963-11-26 | 1 | Details |
| US3112373A | Private branch telephone system with camp on facilities | Expired / Lapsed | 1961-05-08 | 1963-11-26 | 1 | Details |
| US3112372A | Telephone marker translating system | Expired / Lapsed | 1960-10-03 | 1963-11-26 | 1 | Details |
| US3111646A | Method and apparatus for reading cursive script | Expired / Lapsed | 1960-05-31 | 1963-11-19 | 2 | Details |
| US3111624A | Automatic system for selectively substituting spare channel… | Expired / Lapsed | 1960-01-04 | 1963-11-19 | 2 | Details |
| US3111561A | Intercept equipment | Expired / Lapsed | 1959-11-23 | 1963-11-19 | 2 | Details |
| US3109963A | Insulated superconducting wire | Expired / Lapsed | 1960-08-29 | 1963-11-05 | 2 | Details |
| US3109897A | Synchronization of pulse transmission systems | Expired / Lapsed | 1960-05-20 | 1963-11-05 | 2 | Details |
| US3109128A | Servo-mechanism control circuit | Expired / Lapsed | 1960-09-19 | 1963-10-29 | 2 | Details |
| US3109070A | Pitch synchronous autocorrelation vocoder | Expired / Lapsed | 1960-08-09 | 1963-10-29 | 2 | Details |
| US3109071A | Telephone call transmitter | Expired / Lapsed | 1959-12-18 | 1963-10-29 | 2 | Details |
| US3108198A | Blocking oscillator frequency divider | Expired / Lapsed | 1961-08-18 | 1963-10-22 | 2 | Details |
| US3107303A | Positive or negative high gain image amplifier | Expired / Lapsed | 1960-12-28 | 1963-10-15 | 2 | Details |
| US3107344A | Self-synchronizing delay line data translation | Expired / Lapsed | 1959-09-29 | 1963-10-15 | 1 | Details |
| US3106699A | Spatially oriented data processing apparatus | Expired / Lapsed | 1958-10-07 | 1963-10-08 | 0 | Details |
| US3106698A | Parallel data processing apparatus | Expired / Lapsed | 1958-04-25 | 1963-10-08 | 2 | Details |
| US3105121A | Repertory dialer | Expired / Lapsed | 1959-04-21 | 1963-09-24 | 2 | Details |
| US3102230A | Electric field controlled semiconductor device | Expired / Lapsed | 1960-05-31 | 1963-08-27 | 2 | Details |
| US3100868A | Light gas detector using thin walled glass tubes for diffus… | Expired / Lapsed | 1958-08-20 | 1963-08-13 | 2 | Details |
| US3095332A | Photosensitive gas phase etching of semiconductors by selec… | Expired / Lapsed | 1961-06-30 | 1963-06-25 | 1 | Details |
| US3090873A | Integrated semiconductor switching device | Expired / Lapsed | 1960-06-21 | 1963-05-21 | 1 | Details |
| US3090942A | Number comparison and display circuits | Expired / Lapsed | 1958-12-18 | 1963-05-21 | 2 | Details |
| US3090008A | Predictive quantization and coding of vision signals | Expired / Lapsed | 1960-10-24 | 1963-05-14 | 2 | Details |
| US3089918A | Telewriting apparatus | Expired / Lapsed | 1960-09-09 | 1963-05-14 | 2 | Details |
| US3090014A | Negative resistance device modulator | Expired / Lapsed | 1959-12-17 | 1963-05-14 | 2 | Details |
| US3087374A | Optical maser elements | Expired / Lapsed | 1961-07-03 | 1963-04-30 | 2 | Details |
| US3088056A | Logic and memory circuit units | Expired / Lapsed | 1959-12-09 | 1963-04-30 | 0 | Details |
| US3085033A | Fabrication of semiconductor devices | Expired / Lapsed | 1960-03-08 | 1963-04-09 | 2 | Details |
| US3085032A | Treatment of gallium arsenide | Expired / Lapsed | 1960-02-26 | 1963-04-09 | 2 | Details |
| US3083267A | Pcm telephone signaling | Expired / Lapsed | 1960-10-20 | 1963-03-26 | 1 | Details |
| US3081434A | Multibranch circuits for translating frequency characterist… | Expired / Lapsed | 1960-04-18 | 1963-03-12 | 4 | Details |
| US3079347A | Terbium and cerium activated calcium fluoride optical maser… | Expired / Lapsed | 1960-10-25 | 1963-02-26 | 2 | Details |
| US3079513A | Ring counter employing nor stages with parallel inputs and … | Expired / Lapsed | 1959-09-25 | 1963-02-26 | 0 | Details |
| US3078373A | Electroluminescent matrix and access device | Expired / Lapsed | 1960-04-21 | 1963-02-19 | 2 | Details |
| US3078196A | Semiconductive switch | Expired / Lapsed | 1959-06-17 | 1963-02-19 | 2 | Details |
| US3076601A | Electronic binary counter and converter | Expired / Lapsed | 1959-08-27 | 1963-02-05 | 2 | Details |
| US3076059A | Signaling system | Expired / Lapsed | 1958-06-20 | 1963-01-29 | 2 | Details |
| US3072894A | Telemetering system | Expired / Lapsed | 1960-06-22 | 1963-01-08 | 1 | Details |
| US3072804A | Pulse position detector utilizing the storage effect of pnp… | Expired / Lapsed | 1959-12-14 | 1963-01-08 | 2 | Details |
| US3071727A | Bandwidth reduction system | Expired / Lapsed | 1961-05-08 | 1963-01-01 | 2 | Details |
| US3071739A | Digital phase equalizer, automatically operative, in accord… | Expired / Lapsed | 1961-04-21 | 1963-01-01 | 2 | Details |
| US3069507A | Autocorrelation vocoder | Expired / Lapsed | 1960-08-09 | 1962-12-18 | 0 | Details |
| US3067485A | Semiconductor diode | Expired / Lapsed | 1958-08-13 | 1962-12-11 | 2 | Details |
| US3065636A | Pressure transducers | Expired / Lapsed | 1960-05-10 | 1962-11-27 | 0 | Details |
| US3064890A | Parallel input fast carry binary counter with feedback rese… | Expired / Lapsed | 1961-05-29 | 1962-11-20 | 0 | Details |
| US3061818A | Magnetic core register circuits | Expired / Lapsed | 1956-12-12 | 1962-10-30 | 0 | Details |
| US3060273A | Standby transfer control circuitry | Expired / Lapsed | 1959-11-25 | 1962-10-23 | 0 | Details |
| US3060327A | Transistor having emitter reversebiased beyond breakdown an… | Expired / Lapsed | 1959-07-02 | 1962-10-23 | 0 | Details |
| US3059158A | Protected semiconductor device and method of making it | Expired / Lapsed | 1959-02-09 | 1962-10-16 | 0 | Details |
| US3057960A | Normalized sound control system | Expired / Lapsed | 1961-03-13 | 1962-10-09 | 0 | Details |
| US3057965A | Braille telephone switchboard unit | Expired / Lapsed | 1960-12-07 | 1962-10-09 | 0 | Details |
| US3057959A | Timing wave generator | Expired / Lapsed | 1960-11-02 | 1962-10-09 | 0 | Details |
| US3057964A | Multifrequency signaling receiver | Expired / Lapsed | 1959-12-14 | 1962-10-09 | 0 | Details |
| US3056888A | Semiconductor triode | Expired / Lapsed | 1960-08-17 | 1962-10-02 | 0 | Details |
| US3055257A | Optical maser cavity | Expired / Lapsed | 1960-10-07 | 1962-09-25 | 0 | Details |
| US3056100A | Temperature compensated field effect resistor | Expired / Lapsed | 1959-12-04 | 1962-09-25 | 0 | Details |
| US3053134A | Optical pulse echo system | Expired / Lapsed | 1948-04-01 | 1962-09-11 | 0 | Details |
| US3051784A | Error-correcting system | Expired / Lapsed | 1961-05-12 | 1962-08-28 | 0 | Details |
| US3051901A | Encoder for pulse code modulation | Expired / Lapsed | 1958-06-24 | 1962-08-28 | 0 | Details |
| US3050581A | Line tracing system | Expired / Lapsed | 1960-08-30 | 1962-08-21 | 0 | Details |
| US3050698A | Semiconductor hall effect devices | Expired / Lapsed | 1960-02-12 | 1962-08-21 | 0 | Details |
| US3050713A | Output selecting circuit | Expired / Lapsed | 1959-12-16 | 1962-08-21 | 0 | Details |
| US3050711A | Automatic character analyzer | Expired / Lapsed | 1959-02-26 | 1962-08-21 | 0 | Details |
| US3048778A | High frequency power meter | Expired / Lapsed | 1959-07-21 | 1962-08-07 | 0 | Details |
| US3047746A | Surge suppression for power supplies | Expired / Lapsed | 1959-12-08 | 1962-07-31 | 0 | Details |
| US3047667A | Transistor crosspoint switching network | Expired / Lapsed | 1958-02-24 | 1962-07-31 | 0 | Details |
| US3046346A | Multiplex signaling system | Expired / Lapsed | 1958-12-17 | 1962-07-24 | 0 | Details |
| US3046525A | Supervisory control system | Expired / Lapsed | 1958-09-16 | 1962-07-24 | 0 | Details |
| US3045215A | Electrical control circuits | Expired / Lapsed | 1959-06-25 | 1962-07-17 | 0 | Details |
| US3042751A | Pulse transmission system | Expired / Lapsed | 1959-03-10 | 1962-07-03 | 0 | Details |
| US3041537A | Transistor test set | Expired / Lapsed | 1959-11-27 | 1962-06-26 | 0 | Details |
| US3041556A | Ultrasonic strip delay line | Expired / Lapsed | 1959-07-01 | 1962-06-26 | 0 | Details |
| US3038029A | Pulse transmission of alternate interchange code | Expired / Lapsed | 1959-06-15 | 1962-06-05 | 0 | Details |
| US3037068A | Retractile tinsel cordage | Expired / Lapsed | 1959-05-04 | 1962-05-29 | 0 | Details |
| US3036290A | Error rate alarm circuit | Expired / Lapsed | 1959-11-12 | 1962-05-22 | 0 | Details |
| US3036161A | Line concentrator control circuit | Expired / Lapsed | 1959-10-26 | 1962-05-22 | 0 | Details |
| US3035257A | Cumulative code translator | Expired / Lapsed | 1959-09-29 | 1962-05-15 | 0 | Details |
| US3035186A | Semiconductor switching apparatus | Expired / Lapsed | 1959-06-15 | 1962-05-15 | 0 | Details |
| US3034345A | Gauges using piezoresistive elements | Expired / Lapsed | 1959-05-19 | 1962-05-15 | 0 | Details |
| US3035211A | Subscriber calling apparatus | Expired / Lapsed | 1958-10-21 | 1962-05-15 | 0 | Details |
| US3034077A | Ultrasonic delay lines | Expired / Lapsed | 1959-04-02 | 1962-05-08 | 0 | Details |
| US3032610A | Encoders for pcm codes of base greater than two | Expired / Lapsed | 1960-03-22 | 1962-05-01 | 0 | Details |
| US3031629A | Power supply system | Expired / Lapsed | 1960-08-16 | 1962-04-24 | 0 | Details |
| US3030448A | Pcm telephone signaling | Expired / Lapsed | 1960-12-30 | 1962-04-17 | 0 | Details |
| US3030450A | Band compression system | Expired / Lapsed | 1958-11-17 | 1962-04-17 | 0 | Details |
| US3030609A | Data storage and retrieval | Expired / Lapsed | 1957-10-11 | 1962-04-17 | 0 | Details |
| US3028084A | Reversible counting relay chain | Expired / Lapsed | 1958-09-11 | 1962-04-03 | 0 | Details |
| US3027427A | Electronic switching network | Expired / Lapsed | 1958-06-06 | 1962-03-27 | 0 | Details |
| US3027550A | Signal pulse detector and register | Expired / Lapsed | 1956-12-31 | 1962-03-27 | 0 | Details |
| US3027547A | Magnetic core circuits | Expired / Lapsed | 1956-12-06 | 1962-03-27 | 0 | Details |
| US3024119A | Glass composition and coated article | Expired / Lapsed | 1959-06-03 | 1962-03-06 | 2 | Details |
| US3021517A | Analog-to-digital converter | Expired / Lapsed | 1960-08-22 | 1962-02-13 | 0 | Details |
| US3021384A | Time divisdion multiplexing of television and telephone mes… | Expired / Lapsed | 1959-12-28 | 1962-02-13 | 0 | Details |
| US3020525A | Record controlled translator | Expired / Lapsed | 1958-04-04 | 1962-02-06 | 0 | Details |
| US3018431A | Alternating current voltage regulator | Expired / Lapsed | 1960-01-04 | 1962-01-23 | 0 | Details |
| US3017091A | Digital error correcting systems | Expired / Lapsed | 1957-03-26 | 1962-01-16 | 0 | Details |
| US3016502A | Spurious mode suppressing wave guide | Expired / Lapsed | 1959-12-23 | 1962-01-09 | 0 | Details |
| US3015809A | Magnetic memory matrix | Expired / Lapsed | 1959-06-19 | 1962-01-02 | 0 | Details |
| US3012203A | Traveling wave parametric amplifier | Expired / Lapsed | 1960-03-07 | 1961-12-05 | 0 | Details |
| US3011089A | Solid state light sensitive storage device | Expired / Lapsed | 1958-04-16 | 1961-11-28 | 0 | Details |
| US3011155A | Electrical memory circuit | Expired / Lapsed | 1957-11-07 | 1961-11-28 | 0 | Details |
| US3011151A | Signal comparison system | Expired / Lapsed | 1956-04-27 | 1961-11-28 | 0 | Details |
| US3010102A | Combination radar and thermalenergy detection system | Expired / Lapsed | 1947-07-05 | 1961-11-21 | 0 | Details |
| US3008668A | Guidance control system | Expired / Lapsed | 1955-06-06 | 1961-11-14 | 0 | Details |
| US3008087A | Signal synchronizing system utilizing adjustable delay appa… | Expired / Lapsed | 1958-04-24 | 1961-11-07 | 0 | Details |
| US3008089A | Semiconductive device comprising p-i-n conductivity layers | Expired / Lapsed | 1958-02-20 | 1961-11-07 | 2 | Details |
| US3008088A | Synchronized multivibrator with selectable clamping means f… | Expired / Lapsed | 1957-11-07 | 1961-11-07 | 0 | Details |
| US3006067A | Thermo-compression bonding of metal to semiconductors, and … | Expired / Lapsed | 1956-10-31 | 1961-10-31 | 4 | Details |
| US3007145A | Synchronizing circuit for magnetic drum | Expired / Lapsed | 1956-05-22 | 1961-10-31 | 0 | Details |
| US3005055A | Tilting dial circuit selector | Expired / Lapsed | 1957-10-08 | 1961-10-17 | 0 | Details |
| US3005053A | Telephone signaling system | Expired / Lapsed | 1957-09-09 | 1961-10-17 | 0 | Details |
| US3003143A | Selecting circuit | Expired / Lapsed | 1959-05-28 | 1961-10-03 | 0 | Details |
| US2999169A | Non-saturating transistor pulse amplifier | Expired / Lapsed | 1956-12-28 | 1961-09-05 | 0 | Details |
| US2998489A | Automatic telephone message service | Expired / Lapsed | 1958-03-25 | 1961-08-29 | 0 | Details |
| US2997577A | Synchronous carrier production | Expired / Lapsed | 1960-01-04 | 1961-08-22 | 0 | Details |
| US2996578A | Bipolar pulse transmission and regeneration | Expired / Lapsed | 1959-01-19 | 1961-08-15 | 0 | Details |
| US2996248A | Supervisory system for an electronic counter | Expired / Lapsed | 1957-12-31 | 1961-08-15 | 0 | Details |
| US2996663A | Magnetic field gradiometer | Expired / Lapsed | 1945-09-29 | 1961-08-15 | 0 | Details |
| US2995101A | Steering apparatus for torpedoes | Expired / Lapsed | 1944-11-20 | 1961-08-08 | 0 | Details |
| US2993154A | Semiconductor switch | Expired / Lapsed | 1960-06-10 | 1961-07-18 | 0 | Details |
| US2992339A | Binary adder circuits | Expired / Lapsed | 1956-11-27 | 1961-07-11 | 0 | Details |
| US2992421A | Induction type translator | Expired / Lapsed | 1956-03-29 | 1961-07-11 | 0 | Details |
| US2989784A | Method of forming a plug of high melting point plastic bond… | Expired / Lapsed | 1957-10-04 | 1961-06-27 | 0 | Details |
| US2989385A | Process for ion bombarding and etching metal | Expired / Lapsed | 1957-05-14 | 1961-06-20 | 0 | Details |
| US2986723A | Synchronization in a system of interconnected units | Expired / Lapsed | 1960-02-26 | 1961-05-30 | 0 | Details |
| US2984789A | Pulse monitoring circuit | Expired / Lapsed | 1958-08-13 | 1961-05-16 | 0 | Details |
| US2984706A | Insertion of framing information in pulse modulation systems | Expired / Lapsed | 1957-12-24 | 1961-05-16 | 0 | Details |
| US2982926A | Delay line | Expired / Lapsed | 1959-07-06 | 1961-05-02 | 0 | Details |
| US2982869A | Semiconductor trigger circuit | Expired / Lapsed | 1959-02-25 | 1961-05-02 | 0 | Details |
| US2979662A | Electrical wave synchronizing circuit | Expired / Lapsed | 1958-11-28 | 1961-04-11 | 0 | Details |
| US2979556A | Semiautomatic teletypewriter tape relay system | Expired / Lapsed | 1956-10-02 | 1961-04-11 | 0 | Details |
| US2978675A | Character recognition system | Expired / Lapsed | 1959-12-10 | 1961-04-04 | 0 | Details |
| US2977632A | Centripetal extruder | Expired / Lapsed | 1959-04-10 | 1961-04-04 | 0 | Details |
| US2978680A | Precession storage delay circuit | Expired / Lapsed | 1957-12-06 | 1961-04-04 | 0 | Details |
| US2978390A | Gold plating solutions | Expired / Lapsed | 1957-07-22 | 1961-04-04 | 2 | Details |
| US2977575A | Cryotron circuits | Expired / Lapsed | 1957-02-15 | 1961-03-28 | 0 | Details |
| US2976487A | Stabilized timing circuit | Expired / Lapsed | 1958-08-07 | 1961-03-21 | 0 | Details |
| US2974568A | Light modulator | Expired / Lapsed | 1957-02-15 | 1961-03-14 | 0 | Details |
| US2974195A | Economy in television transmission | Expired / Lapsed | 1958-10-30 | 1961-03-07 | 0 | Details |
| US2974203A | Ceramic electromechanical transducers | Expired / Lapsed | 1958-04-29 | 1961-03-07 | 2 | Details |
| US2974075A | Treatment of semiconductive devices | Expired / Lapsed | 1957-10-28 | 1961-03-07 | 2 | Details |
| US2973506A | Magnetic translation circuits | Expired / Lapsed | 1958-06-10 | 1961-02-28 | 0 | Details |
| US2971711A | Apparatus for reeling strand | Expired / Lapsed | 1958-12-31 | 1961-02-14 | 0 | Details |
| US2972064A | Zero phase marker indicator | Expired / Lapsed | 1958-11-05 | 1961-02-14 | 0 | Details |
| US2970310A | Light pulse generator | Expired / Lapsed | 1947-09-23 | 1961-01-31 | 0 | Details |
| US2969296A | Thermal expansion fixture for spacing vaporized contacts on… | Expired / Lapsed | 1958-12-08 | 1961-01-24 | 2 | Details |
| US2969216A | Clamps for securing and supporting articles | Expired / Lapsed | 1958-04-25 | 1961-01-24 | 0 | Details |
| US2969419A | Retractile cords | Expired / Lapsed | 1954-09-07 | 1961-01-24 | 0 | Details |
| US2965851A | Tapped ultrasonic delay line | Expired / Lapsed | 1957-12-26 | 1960-12-20 | 0 | Details |
| US2965855A | Electrical circuit | Expired / Lapsed | 1957-04-08 | 1960-12-20 | 0 | Details |
| US2965894A | Altitude control system | Expired / Lapsed | 1956-12-26 | 1960-12-20 | 0 | Details |
| US2964689A | Switching transistors | Expired / Lapsed | 1958-07-17 | 1960-12-13 | 0 | Details |
| US2961350A | Glass coating of circuit elements | Expired / Lapsed | 1959-03-20 | 1960-11-22 | 2 | Details |
| US2961488A | Permutation code selecting circuit | Expired / Lapsed | 1957-12-31 | 1960-11-22 | 0 | Details |
| US2958254A | Optical gaging system | Expired / Lapsed | 1958-03-11 | 1960-11-01 | 0 | Details |
| US2957952A | Code generator | Expired / Lapsed | 1958-05-09 | 1960-10-25 | 0 | Details |
| US2957945A | Timing circuit | Expired / Lapsed | 1957-12-24 | 1960-10-25 | 0 | Details |
| US2957948A | Frequency band compression | Expired / Lapsed | 1956-07-20 | 1960-10-25 | 0 | Details |
| US2956180A | Pulse shift monitoring circuit | Expired / Lapsed | 1958-06-26 | 1960-10-11 | 0 | Details |
| US2956124A | Continuous digital error correcting system | Expired / Lapsed | 1958-05-01 | 1960-10-11 | 0 | Details |
| US2956274A | Object location system | Expired / Lapsed | 1945-08-20 | 1960-10-11 | 0 | Details |
| US2955165A | Electronic telephone switching system | Expired / Lapsed | 1957-10-07 | 1960-10-04 | 0 | Details |
| US2955279A | Selective paging system | Expired / Lapsed | 1955-02-11 | 1960-10-04 | 0 | Details |
| US2954266A | Precision measuring device | Expired / Lapsed | 1957-10-18 | 1960-09-27 | 0 | Details |
| US2953486A | Junction formation by thermal oxidation of semiconductive m… | Expired / Lapsed | 1959-06-01 | 1960-09-20 | 2 | Details |
| US2951229A | Error-detecting and correcting system | Expired / Lapsed | 1959-04-27 | 1960-08-30 | 0 | Details |
| US2951235A | Statistical data accumulator | Expired / Lapsed | 1958-01-15 | 1960-08-30 | 0 | Details |
| US2951240A | Magnetic core circuit | Expired / Lapsed | 1956-10-16 | 1960-08-30 | 0 | Details |
| US2951230A | Shift register counter | Expired / Lapsed | 1955-10-06 | 1960-08-30 | 0 | Details |
| US2951200A | Calibration indicator | Expired / Lapsed | 1954-10-29 | 1960-08-30 | 0 | Details |
| US2949503A | Pulse modulation system framing circuit | Expired / Lapsed | 1958-05-21 | 1960-08-16 | 0 | Details |
| US2948261A | Apparatus for producing printed wiring by metal vaporization | Expired / Lapsed | 1956-12-07 | 1960-08-09 | 0 | Details |
| US2947803A | Clock controlled automatic recycling switching circuit | Expired / Lapsed | 1957-04-24 | 1960-08-02 | 0 | Details |
| US2946984A | Tape-to-card converter circuit | Expired / Lapsed | 1956-05-31 | 1960-07-26 | 0 | Details |
| US2946033A | Polarized connector for printed circuit cards | Expired / Lapsed | 1956-05-15 | 1960-07-19 | 0 | Details |
| US2944321A | Method of fabricating semiconductor devices | Expired / Lapsed | 1958-12-31 | 1960-07-12 | 0 | Details |
| US2941154A | Parallel transistor amplifiers | Expired / Lapsed | 1957-12-10 | 1960-06-14 | 0 | Details |
| US2940042A | Pulse phase detector | Expired / Lapsed | 1957-02-25 | 1960-06-07 | 0 | Details |
| US2939317A | Variable resistance semiconductive devices | Expired / Lapsed | 1955-10-31 | 1960-06-07 | 0 | Details |
| US2939109A | Signaling system | Expired / Lapsed | 1957-12-16 | 1960-05-31 | 0 | Details |
| US2938424A | Reflection sensing system | Expired / Lapsed | 1957-07-11 | 1960-05-31 | 0 | Details |
| US2938194A | Ferroelectric storage circuits | Expired / Lapsed | 1955-07-25 | 1960-05-24 | 0 | Details |
| US2937368A | Means for detecting marking and bypassing defective areas i… | Expired / Lapsed | 1956-12-12 | 1960-05-17 | 0 | Details |
| US2936338A | Switching circuit | Expired / Lapsed | 1957-12-11 | 1960-05-10 | 0 | Details |
| US2936117A | High speed switching circuits employing slow acting compone… | Expired / Lapsed | 1957-05-31 | 1960-05-10 | 0 | Details |
| US2936380A | Light valve logic circuits | Expired / Lapsed | 1955-12-07 | 1960-05-10 | 0 | Details |
| US2936336A | Automatic telephone answering and message recording device | Expired / Lapsed | 1953-01-14 | 1960-05-10 | 0 | Details |
| US2935569A | Time assignment speech interpolation system | Expired / Lapsed | 1957-09-26 | 1960-05-03 | 0 | Details |
| US2933292A | Heat abstracting and shielding means for electron discharge… | Expired / Lapsed | 1955-12-02 | 1960-04-19 | 0 | Details |
| US2930722A | Method of treating silicon | Expired / Lapsed | 1959-02-03 | 1960-03-29 | 1 | Details |
| US2931027A | Visual display apparatus | Expired / Lapsed | 1956-10-19 | 1960-03-29 | 0 | Details |
| US2929922A | Masers and maser communications system | Expired / Lapsed | 1958-07-30 | 1960-03-22 | 0 | Details |
| US2929030A | Transistor multivibrator frequency control | Expired / Lapsed | 1957-12-06 | 1960-03-15 | 0 | Details |
| US2929034A | Magnetic transmission systems | Expired / Lapsed | 1953-04-29 | 1960-03-15 | 0 | Details |
| US2927971A | Subscriber call transmitting system | Expired / Lapsed | 1957-12-30 | 1960-03-08 | 0 | Details |
| US2927967A | Negative impedance repeater | Expired / Lapsed | 1957-10-14 | 1960-03-08 | 0 | Details |
| US2928075A | Ferroelectric storage circuits | Expired / Lapsed | 1955-04-14 | 1960-03-08 | 0 | Details |
| US2927962A | Transmission systems employing quantization | Expired / Lapsed | 1954-04-26 | 1960-03-08 | 0 | Details |
| US2926334A | Error detection circuit | Expired / Lapsed | 1955-04-20 | 1960-02-23 | 0 | Details |
| US2926336A | Ferroelectric device | Expired / Lapsed | 1955-04-14 | 1960-02-23 | 0 | Details |
| US2924666A | Telephone system calling stations identifier | Expired / Lapsed | 1957-09-19 | 1960-02-09 | 0 | Details |
| US2924788A | Linear voltage-to-frequency converter | Expired / Lapsed | 1957-03-14 | 1960-02-09 | 0 | Details |
| US2924711A | Multilevel quantizer | Expired / Lapsed | 1956-11-21 | 1960-02-09 | 0 | Details |
| US2922987A | Information storage system | Expired / Lapsed | 1957-08-05 | 1960-01-26 | 0 | Details |
| US2922965A | Aperture equalizer and phase correction for television | Expired / Lapsed | 1956-08-09 | 1960-01-26 | 0 | Details |
| US2921124A | Method and apparatus for reducing television bandwidth | Expired / Lapsed | 1956-12-10 | 1960-01-12 | 0 | Details |
| US2919358A | Apparatus for converting radiant energy to electromechanica… | Expired / Lapsed | 1955-03-23 | 1959-12-29 | 0 | Details |
| US2917583A | Time separation communication system | Expired / Lapsed | 1953-06-26 | 1959-12-15 | 0 | Details |
| US2916553A | High speed delta modulation encoder | Expired / Lapsed | 1957-05-31 | 1959-12-08 | 0 | Details |
| US2913578A | Multivibrator circuits | Expired / Lapsed | 1954-03-17 | 1959-11-17 | 0 | Details |
| US2912677A | Electrical circuits employing sensing wires threading magne… | Expired / Lapsed | 1953-12-31 | 1959-11-10 | 0 | Details |
| US2911463A | High resolution scanning system | Expired / Lapsed | 1957-12-30 | 1959-11-03 | 0 | Details |
| US2911588A | Bridge circuits | Expired / Lapsed | 1955-12-23 | 1959-11-03 | 0 | Details |
| US2911544A | Shift register circuit controlled by a pulse generating cir… | Expired / Lapsed | 1955-10-06 | 1959-11-03 | 0 | Details |
| US2909623A | Interlaced feedback amplifier | Expired / Lapsed | 1957-06-27 | 1959-10-20 | 0 | Details |
| US2909600A | Two-way television over telephone lines | Expired / Lapsed | 1956-07-26 | 1959-10-20 | 0 | Details |
| US2909675A | Bistable frequency divider | Expired / Lapsed | 1955-05-10 | 1959-10-20 | 0 | Details |
| US2909620A | Mu-beta measurement in feedback systems | Expired / Lapsed | 1954-01-05 | 1959-10-20 | 0 | Details |
| US2908873A | Automatic phase equalizer | Expired / Lapsed | 1957-08-05 | 1959-10-13 | 0 | Details |
| US2906816A | Method and apparatus for reducing television bandwidth | Expired / Lapsed | 1956-07-24 | 1959-09-29 | 0 | Details |
| US2906893A | Transistor blocking oscillator | Expired / Lapsed | 1956-07-06 | 1959-09-29 | 0 | Details |
| US2907019A | Code translator | Expired / Lapsed | 1955-09-06 | 1959-09-29 | 0 | Details |
| US2905756A | Method and apparatus for reducing television bandwidth | Expired / Lapsed | 1956-11-30 | 1959-09-22 | 0 | Details |
| US2904742A | Current supply apparatus | Expired / Lapsed | 1957-09-16 | 1959-09-15 | 0 | Details |
| US2903598A | Beam positioning system | Expired / Lapsed | 1956-03-26 | 1959-09-08 | 0 | Details |
| US2903676A | Binary counter transistor circuit | Expired / Lapsed | 1955-10-18 | 1959-09-08 | 0 | Details |
| US2901381A | Method of making electrical resistors | Expired / Lapsed | 1956-10-12 | 1959-08-25 | 2 | Details |
| US2898477A | Piezoelectric field effect semiconductor device | Expired / Lapsed | 1955-10-31 | 1959-08-04 | 0 | Details |
| US2896160A | Time interval encoder | Expired / Lapsed | 1954-09-20 | 1959-07-21 | 0 | Details |
| US2895005A | Two-way television over telephone lines | Expired / Lapsed | 1954-09-30 | 1959-07-14 | 0 | Details |
| US2892888A | Digital system with error elimination | Expired / Lapsed | 1958-02-10 | 1959-06-30 | 0 | Details |
| US2892508A | Separation of gases by diffusion | Expired / Lapsed | 1957-04-17 | 1959-06-30 | 0 | Details |
| US2888557A | Frequency divider circuits | Expired / Lapsed | 1954-09-17 | 1959-05-26 | 0 | Details |
| US2887664A | Faraday-effect device for electro-magnetic waves | Expired / Lapsed | 1955-09-13 | 1959-05-19 | 0 | Details |
| US2886802A | Timing pulse generator circuit for magnetic drum | Expired / Lapsed | 1955-12-20 | 1959-05-12 | 0 | Details |
| US2885572A | Transistor pulse transmission circuits | Expired / Lapsed | 1955-10-20 | 1959-05-05 | 0 | Details |
| US2885506A | Fluid pressure sensitive control devices | Expired / Lapsed | 1955-04-28 | 1959-05-05 | 0 | Details |
| US2884607A | Semiconductor nonlinear capacitance diode | Expired / Lapsed | 1958-04-18 | 1959-04-28 | 0 | Details |
| US2884491A | Message-waiting signal for telephone subscribers | Expired / Lapsed | 1958-01-24 | 1959-04-28 | 0 | Details |
| US2884613A | Electrical terminal block | Expired / Lapsed | 1955-03-25 | 1959-04-28 | 0 | Details |
| US2883470A | Communication switching network | Expired / Lapsed | 1956-10-19 | 1959-04-21 | 0 | Details |
| US2883257A | Electron beam recording | Expired / Lapsed | 1953-05-15 | 1959-04-21 | 0 | Details |
| US2880330A | Non-saturating transistor trigger circuits | Expired / Lapsed | 1954-06-29 | 1959-03-31 | 0 | Details |
| US2879190A | Fabrication of silicon devices | Expired / Lapsed | 1957-03-22 | 1959-03-24 | 2 | Details |
| US2877359A | Semiconductor signal storage device | Expired / Lapsed | 1956-04-20 | 1959-03-10 | 0 | Details |
| US2877343A | Radiant energy communication system with carrier control | Expired / Lapsed | 1955-05-18 | 1959-03-10 | 0 | Details |
| US2875505A | Semiconductor translating device | Expired / Lapsed | 1952-12-11 | 1959-03-03 | 0 | Details |
| US2873372A | Electric circuit interrupters | Expired / Lapsed | 1957-12-12 | 1959-02-10 | 0 | Details |
| US2873385A | Transistor data storage and gate circuit | Expired / Lapsed | 1955-10-06 | 1959-02-10 | 0 | Details |
| US2872703A | Extrusion apparatus | Expired / Lapsed | 1955-01-24 | 1959-02-10 | 0 | Details |
| US2871283A | Cable termination | Expired / Lapsed | 1956-10-11 | 1959-01-27 | 0 | Details |
| US2871376A | Temperature sensitive transistor control circuit | Expired / Lapsed | 1953-12-31 | 1959-01-27 | 0 | Details |
| US2868880A | Remote control of telephone answering and message recording… | Expired / Lapsed | 1957-02-07 | 1959-01-13 | 0 | Details |
| US2866014A | Piezoresistive acoustic transducer | Expired / Lapsed | 1955-10-31 | 1958-12-23 | 0 | Details |
| US2864975A | Transistor circuit for operating a relay | Expired / Lapsed | 1957-07-12 | 1958-12-16 | 0 | Details |
| US2864008A | Relay selecting circuit | Expired / Lapsed | 1955-12-28 | 1958-12-09 | 0 | Details |
| US2862992A | Electrical network assembly | Expired / Lapsed | 1954-05-03 | 1958-12-02 | 0 | Details |
| US2862115A | Semiconductor circuit controlling devices | Expired / Lapsed | 1955-07-13 | 1958-11-25 | 0 | Details |
| US2861029A | Methods of making printed wiring circuits | Expired / Lapsed | 1955-12-14 | 1958-11-18 | 0 | Details |
| US2861018A | Fabrication of semiconductive devices | Expired / Lapsed | 1955-06-20 | 1958-11-18 | 2 | Details |
| US2861181A | Delay circuits | Expired / Lapsed | 1953-06-01 | 1958-11-18 | 0 | Details |
| US2860284A | Cathode ray tube circuit to maintain uniform trace intensity | Expired / Lapsed | 1955-11-22 | 1958-11-11 | 0 | Details |
| US2860258A | Transistor decade counter | Expired / Lapsed | 1954-09-17 | 1958-11-11 | 0 | Details |
| US2859283A | Communication switching network | Expired / Lapsed | 1956-10-19 | 1958-11-04 | 0 | Details |
| US2858246A | Silicon single crystal conductor devices | Expired / Lapsed | 1957-04-22 | 1958-10-28 | 2 | Details |
| US2857626A | Methods of encapsulating articles | Expired / Lapsed | 1955-07-18 | 1958-10-28 | 0 | Details |
| US2858524A | Recording scanner | Expired / Lapsed | 1953-11-13 | 1958-10-28 | 0 | Details |
| US2857465A | Vocoder transmission system | Expired / Lapsed | 1955-11-21 | 1958-10-21 | 0 | Details |
| US2856544A | Semiconductive pulse translator | Expired / Lapsed | 1956-04-18 | 1958-10-14 | 0 | Details |
| US2855540A | Beam positioning system | Expired / Lapsed | 1956-04-27 | 1958-10-07 | 0 | Details |
| US2855524A | Semiconductive switch | Expired / Lapsed | 1955-11-22 | 1958-10-07 | 0 | Details |
| US2854542A | Vibratory signaling device | Expired / Lapsed | 1955-05-24 | 1958-09-30 | 0 | Details |
| US2854603A | Magnetrons | Expired / Lapsed | 1955-05-23 | 1958-09-30 | 0 | Details |
| US2854191A | Computation of correlation | Expired / Lapsed | 1953-11-23 | 1958-09-30 | 0 | Details |
| US2853694A | Electron discharge tube circuit | Expired / Lapsed | 1952-06-11 | 1958-09-23 | 0 | Details |
| US2852677A | High frequency negative resistance device | Expired / Lapsed | 1955-06-28 | 1958-09-16 | 0 | Details |
| US2850650A | Transistor current limiter | Expired / Lapsed | 1956-03-29 | 1958-09-02 | 0 | Details |
| US2850694A | Current supply apparatus for load voltage regulation | Expired / Lapsed | 1954-07-07 | 1958-09-02 | 0 | Details |
| US2848739A | Methods of and apparatus for making cellular plastic produc… | Expired / Lapsed | 1955-09-30 | 1958-08-26 | 0 | Details |
| US2849626A | Monostable circuit | Expired / Lapsed | 1955-04-15 | 1958-08-26 | 0 | Details |
| US2849685A | Non-reciprocal multibranch wave guide component | Expired / Lapsed | 1953-08-17 | 1958-08-26 | 0 | Details |
| US2849684A | Non-reciprocal wave transmission | Expired / Lapsed | 1953-07-31 | 1958-08-26 | 0 | Details |
| US2848545A | Radiant energy signaling system | Expired / Lapsed | 1955-09-27 | 1958-08-19 | 0 | Details |
| US2844693A | Wire-wound vitreous enamel resistors | Expired / Lapsed | 1954-10-25 | 1958-07-22 | 2 | Details |
| US2843745A | Tone generator | Expired / Lapsed | 1956-05-11 | 1958-07-15 | 0 | Details |
| US2843838A | Ferromagnetic translating apparatus | Expired / Lapsed | 1955-08-23 | 1958-07-15 | 0 | Details |
| US2843813A | Magnetic amplifiers | Expired / Lapsed | 1953-12-28 | 1958-07-15 | 0 | Details |
| US2843447A | Probability oscillograph | Expired / Lapsed | 1951-11-01 | 1958-07-15 | 0 | Details |
| US2842463A | Vapor deposited metal films | Expired / Lapsed | 1953-09-04 | 1958-07-08 | 2 | Details |
| US2840728A | Non-saturating transistor circuits | Expired / Lapsed | 1955-04-26 | 1958-06-24 | 0 | Details |
| US2840820A | Artificial medium of variable dielectric constant | Expired / Lapsed | 1954-04-14 | 1958-06-24 | 0 | Details |
| US2840784A | Method of testing electrical devices | Expired / Lapsed | 1953-12-01 | 1958-06-24 | 0 | Details |
| US2838797A | Method of and apparatus for sealing electrical components i… | Expired / Lapsed | 1954-05-06 | 1958-06-17 | 0 | Details |
| US2838687A | Nonlinear resonant circuit devices | Expired / Lapsed | 1955-08-09 | 1958-06-10 | 0 | Details |
| US2837642A | Pulse rate discriminator | Expired / Lapsed | 1953-12-17 | 1958-06-03 | 0 | Details |
| US2836523A | Manufacture of semiconductive devices | Expired / Lapsed | 1956-08-02 | 1958-05-27 | 2 | Details |
| US2835741A | Magnetic core signal generator | Expired / Lapsed | 1956-11-01 | 1958-05-20 | 0 | Details |
| US2834697A | Process for vapor-solid diffusion of a conductivity-type de… | Expired / Lapsed | 1956-05-18 | 1958-05-13 | 2 | Details |
| US2833921A | Automatic continuous zero-setting of a balanced detector | Expired / Lapsed | 1954-12-30 | 1958-05-06 | 0 | Details |
| US2831986A | Semiconductor trigger circuit | Expired / Lapsed | 1955-09-07 | 1958-04-22 | 0 | Details |
| US2832013A | Printed wire circuit card inter-connection apparatus | Expired / Lapsed | 1954-11-12 | 1958-04-22 | 0 | Details |
| US2830642A | Tool for forming tabs on cylindrical shell by cutting and b… | Expired / Lapsed | 1956-01-25 | 1958-04-15 | 0 | Details |
| US2831113A | Transistor relaxation circuits | Expired / Lapsed | 1954-10-14 | 1958-04-15 | 0 | Details |
| US2831126A | Bistable transistor coincidence gate | Expired / Lapsed | 1954-08-13 | 1958-04-15 | 0 | Details |
| US2830285A | Storage system | Expired / Lapsed | 1955-10-18 | 1958-04-08 | 0 | Details |
| US2829422A | Methods of fabricating semiconductor signal translating dev… | Expired / Lapsed | 1952-05-21 | 1958-04-08 | 2 | Details |
| US2829280A | Stair-step wave form generator | Expired / Lapsed | 1953-03-05 | 1958-04-01 | 0 | Details |
| US2828362A | Digit data transmission system | Expired / Lapsed | 1956-01-24 | 1958-03-25 | 0 | Details |
| US2828414A | Demodulation of vestigial sideband signals | Expired / Lapsed | 1953-01-21 | 1958-03-25 | 0 | Details |
| US2828071A | Selectable base counter | Expired / Lapsed | 1951-12-27 | 1958-03-25 | 0 | Details |
| US2826638A | Signaling system | Expired / Lapsed | 1952-04-26 | 1958-03-11 | 0 | Details |
| US2825764A | Cross-control compandor used as echo suppressors | Expired / Lapsed | 1954-02-24 | 1958-03-04 | 0 | Details |
| US2824228A | Pulse train modification circuits | Expired / Lapsed | 1954-12-30 | 1958-02-18 | 0 | Details |
| US2820987A | Methods of and apparatus for controlling the application of… | Expired / Lapsed | 1955-06-07 | 1958-01-28 | 0 | Details |
| US2820932A | Contact structure | Expired / Lapsed | 1956-03-07 | 1958-01-21 | 1 | Details |
| US2820155A | Negative impedance bistable signaloperated switch | Expired / Lapsed | 1955-03-09 | 1958-01-14 | 0 | Details |
| US2818558A | Key pulsing circuit | Expired / Lapsed | 1954-06-17 | 1957-12-31 | 0 | Details |
| US2817711A | Band compression system | Expired / Lapsed | 1954-05-10 | 1957-12-24 | 0 | Details |
| US2817828A | Multifrequency high speed signaling system employing pulses… | Expired / Lapsed | 1953-10-07 | 1957-12-24 | 0 | Details |
| US2817079A | Switching network using diodes and transformers | Expired / Lapsed | 1956-05-22 | 1957-12-17 | 0 | Details |
| US2817061A | Asymmetrical delta modulation system | Expired / Lapsed | 1955-06-07 | 1957-12-17 | 0 | Details |
| US2814779A | Microwave detector | Expired / Lapsed | 1954-12-14 | 1957-11-26 | 0 | Details |
| US2813233A | Semiconductive device | Expired / Lapsed | 1954-07-01 | 1957-11-12 | 0 | Details |
| US2813149A | Telegraph transmission error register | Expired / Lapsed | 1954-04-19 | 1957-11-12 | 0 | Details |
| US2812446A | Photo-resistance device | Expired / Lapsed | 1954-03-05 | 1957-11-05 | 1 | Details |
| US2812468A | Spatial harmonic traveling wave tube | Expired / Lapsed | 1952-12-30 | 1957-11-05 | 0 | Details |
| US2812467A | Electron beam system | Expired / Lapsed | 1952-10-10 | 1957-11-05 | 0 | Details |
| US2812499A | Helix assembly for traveling wave tube | Expired / Lapsed | 1952-07-11 | 1957-11-05 | 0 | Details |
| US2810854A | Serpentine traveling wave tube | Expired / Lapsed | 1951-10-06 | 1957-10-22 | 0 | Details |
| US2808509A | Frequency controlled variable oscillator | Expired / Lapsed | 1954-03-19 | 1957-10-01 | 0 | Details |
| US2808584A | Directional radiator | Expired / Lapsed | 1954-01-29 | 1957-10-01 | 0 | Details |
| US2806200A | Ambient temperature compensation of thermistors | Expired / Lapsed | 1952-12-17 | 1957-09-10 | 0 | Details |
| US2805370A | Alloyed connections to semiconductors | Expired / Lapsed | 1956-04-26 | 1957-09-03 | 1 | Details |
| US2805397A | Semiconductor signal translating devices | Expired / Lapsed | 1952-10-31 | 1957-09-03 | 0 | Details |
| US2802760A | Oxidation of semiconductive surfaces for controlled diffusi… | Expired / Lapsed | 1955-12-02 | 1957-08-13 | 2 | Details |
| US2802940A | Multivibrator circuit | Expired / Lapsed | 1953-06-26 | 1957-08-13 | 0 | Details |
| US2802118A | Transistor amplifier circuits | Expired / Lapsed | 1954-06-17 | 1957-08-06 | 0 | Details |
| US2802149A | Contact protection circuits | Expired / Lapsed | 1953-12-30 | 1957-08-06 | 0 | Details |
| US2801287A | Control of regular and distant talking subscribers sets | Expired / Lapsed | 1954-07-16 | 1957-07-30 | 0 | Details |
| US2801296A | D.-c. summing amplifier drift correction | Expired / Lapsed | 1954-02-09 | 1957-07-30 | 0 | Details |
| US2799006A | Multiplexing various modes in composite conductors | Expired / Lapsed | 1953-03-24 | 1957-07-09 | 0 | Details |
| US2797862A | Digital computer | Expired / Lapsed | 1951-11-08 | 1957-07-02 | 0 | Details |
| US2797171A | Method of uniformly applying lacquer to paper strips | Expired / Lapsed | 1951-04-25 | 1957-06-25 | 0 | Details |
| US2796563A | Semiconductive devices | Expired / Lapsed | 1955-06-10 | 1957-06-18 | 2 | Details |
| US2795648A | Dielectric amplifier employing ferroelectric materials | Expired / Lapsed | 1952-10-17 | 1957-06-11 | 0 | Details |
| US2794970A | Identification of serial stored information | Expired / Lapsed | 1955-07-05 | 1957-06-04 | 0 | Details |
| US2794535A | Sensing devices for selective delivery conveyors | Expired / Lapsed | 1955-01-20 | 1957-06-04 | 0 | Details |
| US2794863A | Semiconductor translating device and circuit | Expired / Lapsed | 1951-07-20 | 1957-06-04 | 0 | Details |
| US2793420A | Electrical contacts to silicon | Expired / Lapsed | 1955-04-22 | 1957-05-28 | 1 | Details |
| US2792540A | Junction transistor | Expired / Lapsed | 1955-08-04 | 1957-05-14 | 0 | Details |
| US2791759A | Semiconductive device | Expired / Lapsed | 1955-02-18 | 1957-05-07 | 2 | Details |
| US2791758A | Semiconductive translating device | Expired / Lapsed | 1955-02-18 | 1957-05-07 | 2 | Details |
| US2791760A | Semiconductive translating device | Expired / Lapsed | 1955-02-18 | 1957-05-07 | 2 | Details |
| US2790940A | Silicon rectifier and method of manufacture | Expired / Lapsed | 1955-04-22 | 1957-04-30 | 1 | Details |
| US2789254A | Lightning protection circuits | Expired / Lapsed | 1954-04-23 | 1957-04-16 | 0 | Details |
| US2789267A | System for testing pulse generators | Expired / Lapsed | 1953-05-26 | 1957-04-16 | 0 | Details |
| US2787712A | Transistor multivibrator circuits | Expired / Lapsed | 1954-10-04 | 1957-04-02 | 0 | Details |
| US2785322A | Stable liquid electrodes | Expired / Lapsed | 1953-08-04 | 1957-03-12 | 2 | Details |
| US2782985A | Tape control arrangement for computer | Expired / Lapsed | 1952-06-12 | 1957-02-26 | 0 | Details |
| US2780765A | Solar energy converting apparatus | Expired / Lapsed | 1954-03-05 | 1957-02-05 | 2 | Details |
| US2779545A | Continuous strand reeling apparatus | Expired / Lapsed | 1955-03-30 | 1957-01-29 | 0 | Details |
| US2779822A | Communication switching system employing gas tubes | Expired / Lapsed | 1955-03-25 | 1957-01-29 | 0 | Details |
| US2779539A | Multiple code wheel analogue-digital translator | Expired / Lapsed | 1954-04-19 | 1957-01-29 | 0 | Details |
| US2778956A | Semiconductor signal translating devices | Expired / Lapsed | 1952-10-31 | 1957-01-22 | 0 | Details |
| US2778885A | Semiconductor signal translating devices | Expired / Lapsed | 1952-10-31 | 1957-01-22 | 0 | Details |
| US2778978A | Multivibrator load circuit | Expired / Lapsed | 1952-09-19 | 1957-01-22 | 0 | Details |
| US2777974A | Protection of semiconductive devices by gaseous ambients | Expired / Lapsed | 1955-06-08 | 1957-01-15 | 0 | Details |
| US2777956A | Square wave generator | Expired / Lapsed | 1954-07-02 | 1957-01-15 | 0 | Details |
| US2776380A | Electrical circuits employing magnetic cores | Expired / Lapsed | 1954-04-27 | 1957-01-01 | 0 | Details |
| US2776371A | Quantizing system employing cathode ray tube | Expired / Lapsed | 1952-07-18 | 1957-01-01 | 0 | Details |
| US2775727A | Digital to analogue converter with digital feedback control | Expired / Lapsed | 1954-12-08 | 1956-12-25 | 0 | Details |
| US2774872A | Phase shifting circuit | Expired / Lapsed | 1952-12-17 | 1956-12-18 | 0 | Details |
| US2774890A | Nonreciprocal transmitting devices | Expired / Lapsed | 1952-08-30 | 1956-12-18 | 0 | Details |
| US2771519A | Routine trunk test circuit | Expired / Lapsed | 1955-06-29 | 1956-11-20 | 0 | Details |
| US2770761A | Semiconductor translators containing enclosed active juncti… | Expired / Lapsed | 1954-12-16 | 1956-11-13 | 0 | Details |
| US2769861A | Reduction of interference in pulse reception | Expired / Lapsed | 1953-10-21 | 1956-11-06 | 0 | Details |
| US2767358A | Semiconductor signal translating devices | Expired / Lapsed | 1952-12-16 | 1956-10-16 | 0 | Details |
| US2767375A | Automatic meter calibrator | Expired / Lapsed | 1952-12-09 | 1956-10-16 | 0 | Details |
| US2766480A | Methods of and apparatus for extruding cellular plastics | Expired / Lapsed | 1952-08-28 | 1956-10-16 | 0 | Details |
| US2767246A | Automatic message accounting system | Expired / Lapsed | 1952-01-04 | 1956-10-16 | 0 | Details |
| US2765441A | Apparatus for monitoring and extruding plastic materials | Expired / Lapsed | 1953-09-03 | 1956-10-02 | 0 | Details |
| US2764642A | Semiconductor signal translating devices | Expired / Lapsed | 1952-10-31 | 1956-09-25 | 0 | Details |
| US2764636A | Dial telephone system arranged for operator or machine anno… | Expired / Lapsed | 1952-02-27 | 1956-09-25 | 0 | Details |
| US2764634A | Magnetic recording dial pulse storage register | Expired / Lapsed | 1950-09-07 | 1956-09-25 | 0 | Details |
| US2763726A | Telephone ringing-signal transmission system | Expired / Lapsed | 1954-09-10 | 1956-09-18 | 0 | Details |
| US2761909A | Multifrequency oscillator | Expired / Lapsed | 1953-01-28 | 1956-09-04 | 0 | Details |
| US2759861A | Process of making photoconductive compounds | Expired / Lapsed | 1954-09-22 | 1956-08-21 | 2 | Details |
| US2760007A | Two-stage transistor feedback amplifier | Expired / Lapsed | 1953-08-06 | 1956-08-21 | 0 | Details |
| US2760087A | Transistor memory circuits | Expired / Lapsed | 1951-11-19 | 1956-08-21 | 0 | Details |
| US2758787A | Serial binary digital multiplier | Expired / Lapsed | 1951-11-27 | 1956-08-14 | 0 | Details |
| US2758788A | Binary code translator, adder, and register | Expired / Lapsed | 1951-11-10 | 1956-08-14 | 0 | Details |
| US2759047A | Pulse transmission system and regenerative repeater therefor | Expired / Lapsed | 1950-12-27 | 1956-08-14 | 0 | Details |
| US2759044A | Beam aperature correction in horizontal and vertical direct… | Expired / Lapsed | 1950-11-24 | 1956-08-14 | 0 | Details |
| US2757243A | Transistor circuits | Expired / Lapsed | 1951-09-17 | 1956-07-31 | 0 | Details |
| US2755436A | Method and apparatus for making insertion loss measurements | Expired / Lapsed | 1952-05-09 | 1956-07-17 | 0 | Details |
| US2754368A | Telephone system | Expired / Lapsed | 1952-05-03 | 1956-07-10 | 0 | Details |
| US2750627A | Apparatus for working and advancing a plastic material | Expired / Lapsed | 1954-10-06 | 1956-06-19 | 2 | Details |
| US2751549A | Current supply apparatus | Expired / Lapsed | 1954-02-25 | 1956-06-19 | 0 | Details |
| US2751550A | Current supply apparatus | Expired / Lapsed | 1953-10-12 | 1956-06-19 | 0 | Details |
| US2751545A | Transistor circuits | Expired / Lapsed | 1953-03-10 | 1956-06-19 | 0 | Details |
| US2750921A | Tension control apparatus for thermal vaporizing coating de… | Expired / Lapsed | 1953-01-12 | 1956-06-19 | 1 | Details |
| US2750541A | Semiconductor translating device | Expired / Lapsed | 1950-01-31 | 1956-06-12 | 1 | Details |
| US2748350A | Ultra-high frequency selective mode directional coupler | Expired / Lapsed | 1951-09-05 | 1956-05-29 | 0 | Details |
| US2745958A | Translating arrangement | Expired / Lapsed | 1953-03-09 | 1956-05-15 | 0 | Details |
| US2746036A | Device for coupling between free space and an electron stre… | Expired / Lapsed | 1952-03-25 | 1956-05-15 | 0 | Details |
| US2744970A | Semiconductor signal translating devices | Expired / Lapsed | 1951-08-24 | 1956-05-08 | 2 | Details |
| US2744308A | Semi-conductor translating device and method of manufacture | Expired / Lapsed | 1950-11-17 | 1956-05-08 | 0 | Details |
| US2745069A | Microwave magnetized ferrite attenuator | Expired / Lapsed | 1950-05-17 | 1956-05-08 | 1 | Details |
| US2744198A | Transistor trigger circuits | Expired / Lapsed | 1951-11-02 | 1956-05-01 | 0 | Details |
| US2743367A | Frequency multiplier apparatus | Expired / Lapsed | 1953-04-23 | 1956-04-24 | 0 | Details |
| US2743322A | Solid state amplifier | Expired / Lapsed | 1952-11-29 | 1956-04-24 | 0 | Details |
| US2743362A | Automatic frequency control | Expired / Lapsed | 1951-05-24 | 1956-04-24 | 0 | Details |
| US2743419A | Frequency measuring apparatus | Expired / Lapsed | 1950-10-04 | 1956-04-24 | 0 | Details |
| US2740901A | Differential photocell detector using junction semiconducto… | Expired / Lapsed | 1951-12-29 | 1956-04-03 | 2 | Details |
| US2740838A | Pulse transmission system | Expired / Lapsed | 1951-08-17 | 1956-04-03 | 0 | Details |
| US2740940A | High speed negative resistance | Expired / Lapsed | 1950-12-08 | 1956-04-03 | 0 | Details |
| US2739298A | Multifrequency high speed calling signal generator | Expired / Lapsed | 1953-01-07 | 1956-03-20 | 0 | Details |
| US2738382A | Magnetic drum dial pulse recording and storage registers | Expired / Lapsed | 1951-01-27 | 1956-03-13 | 0 | Details |
| US2737598A | Photoelectric relay device | Expired / Lapsed | 1950-10-27 | 1956-03-06 | 0 | Details |
| US2736894A | Directive antenna systems | Expired / Lapsed | 1946-01-22 | 1956-02-28 | 0 | Details |
| US2730617A | Timing circuit | Expired / Lapsed | 1951-12-05 | 1956-01-10 | 0 | Details |
| US2730576A | Miniaturized transistor amplifier circuit | Expired / Lapsed | 1951-09-17 | 1956-01-10 | 0 | Details |
| US2730579A | Order wire and alarm circuits for carrier systems | Expired / Lapsed | 1950-11-25 | 1956-01-10 | 0 | Details |
| US2730470A | Method of making semi-conductor crystals | Expired / Lapsed | 1950-06-15 | 1956-01-10 | 2 | Details |
| US2726291A | Traveling wave tube | Expired / Lapsed | 1953-12-07 | 1955-12-06 | 0 | Details |
| US2726370A | Negative impedance converters employing transistors | Expired / Lapsed | 1952-09-17 | 1955-12-06 | 0 | Details |
| US2726074A | Acceleration measuring system | Expired / Lapsed | 1950-05-19 | 1955-12-06 | 0 | Details |
| US2725315A | Method of fabricating semiconductive bodies | Expired / Lapsed | 1952-11-14 | 1955-11-29 | 2 | Details |
| US2725317A | Method of fabricating and heat treating semiconductors | Expired / Lapsed | 1952-04-24 | 1955-11-29 | 2 | Details |
| US2724780A | Inhibited trigger circuits | Expired / Lapsed | 1951-10-31 | 1955-11-22 | 0 | Details |
| US2724742A | Suppressed-carrier amplitude modulation | Expired / Lapsed | 1951-05-05 | 1955-11-22 | 0 | Details |
| US2724740A | Quantized transmission with variable quanta | Expired / Lapsed | 1950-06-29 | 1955-11-22 | 0 | Details |
| US2724103A | Electrical circuits employing magnetic core memory elements | Expired / Lapsed | 1953-12-31 | 1955-11-15 | 0 | Details |
| US2723312A | Magnetic drum dial pulse recording and storage registers | Expired / Lapsed | 1954-09-15 | 1955-11-08 | 0 | Details |
| US2723308A | Automatic transcribing system | Expired / Lapsed | 1953-03-19 | 1955-11-08 | 0 | Details |
| US2723311A | Common control telephone systems | Expired / Lapsed | 1953-03-05 | 1955-11-08 | 0 | Details |
| US2723355A | Diode gate circuit | Expired / Lapsed | 1952-12-23 | 1955-11-08 | 0 | Details |
| US2722490A | Germanium elements and methods of preparing same | Expired / Lapsed | 1950-07-24 | 1955-11-01 | 1 | Details |
| US2721935A | Duplex radio telephone system | Expired / Lapsed | 1951-12-28 | 1955-10-25 | 0 | Details |
| US2720557A | Time division pulse code modulation system employing contin… | Expired / Lapsed | 1948-12-24 | 1955-10-11 | 0 | Details |
| US2719960A | Alarm sending system | Expired / Lapsed | 1954-04-30 | 1955-10-04 | 0 | Details |
| US2719961A | Electrical circuit employing magnetic cores | Expired / Lapsed | 1954-04-27 | 1955-10-04 | 0 | Details |
| US2719964A | Magnetic surface writing circuit utilizing magnetic cores | Expired / Lapsed | 1953-11-20 | 1955-10-04 | 0 | Details |
| US2719773A | Electrical circuit employing magnetic cores | Expired / Lapsed | 1953-11-20 | 1955-10-04 | 0 | Details |
| US2719917A | Precision sweep calibrator | Expired / Lapsed | 1952-03-14 | 1955-10-04 | 0 | Details |
| US2719289A | Electrical conversion system with high and low voltage alarm | Expired / Lapsed | 1952-05-16 | 1955-09-27 | 0 | Details |
| US2719270A | Transmission regulation | Expired / Lapsed | 1952-01-23 | 1955-09-27 | 0 | Details |
| US2719188A | Non-synchronous time division multiplex telephone transmiss… | Expired / Lapsed | 1950-05-05 | 1955-09-27 | 0 | Details |
| US2718589A | Radio relay system | Expired / Lapsed | 1950-06-29 | 1955-09-20 | 0 | Details |
| US2717956A | Reduction of quadrature distortion | Expired / Lapsed | 1952-11-29 | 1955-09-13 | 0 | Details |
| US2717342A | Semiconductor translating devices | Expired / Lapsed | 1952-10-28 | 1955-09-06 | 0 | Details |
| US2717279A | Multiparty selective signaling and identification system | Expired / Lapsed | 1951-12-28 | 1955-09-06 | 0 | Details |
| US2717373A | Ferroelectric storage device and circuit | Expired / Lapsed | 1951-12-14 | 1955-09-06 | 0 | Details |
| US2717372A | Ferroelectric storage device and circuit | Expired / Lapsed | 1951-11-01 | 1955-09-06 | 0 | Details |
| US2716729A | Transistor circuits with constant output current | Expired / Lapsed | 1951-11-24 | 1955-08-30 | 0 | Details |
| US2714642A | High speed relay of electromechanical transducer material | Expired / Lapsed | 1952-07-10 | 1955-08-02 | 0 | Details |
| US2714702A | Circuits, including semiconductor device | Expired / Lapsed | 1951-02-16 | 1955-08-02 | 0 | Details |
| US2714182A | Hall effect devices | Expired / Lapsed | 1952-06-21 | 1955-07-26 | 2 | Details |
| US2711515A | Delay line | Expired / Lapsed | 1950-09-29 | 1955-06-21 | 0 | Details |
| US2709787A | Semiconductor signal translating device | Expired / Lapsed | 1953-09-24 | 1955-05-31 | 1 | Details |
| US2709147A | Methods for bonding silica bodies | Expired / Lapsed | 1951-09-12 | 1955-05-24 | 2 | Details |
| US2708748A | Code conversion | Expired / Lapsed | 1954-04-13 | 1955-05-17 | 0 | Details |
| US2707235A | Frequency selective systems | Expired / Lapsed | 1947-04-26 | 1955-04-26 | 0 | Details |
| US2706326A | Polarization process for pseudocubic ferroelectrics | Expired / Lapsed | 1952-04-23 | 1955-04-19 | 0 | Details |
| US2705742A | High speed continuous spectrum analysis | Expired / Lapsed | 1951-09-15 | 1955-04-05 | 0 | Details |
| US2704782A | Retractile cords and methods of making the same | Expired / Lapsed | 1950-08-30 | 1955-03-22 | 0 | Details |
| US2703368A | Pulse regeneration | Expired / Lapsed | 1953-10-21 | 1955-03-01 | 0 | Details |
| US2703280A | Counting circuit control for electrophotographic printers | Expired / Lapsed | 1950-05-17 | 1955-03-01 | 2 | Details |
| US2702838A | Semiconductor signal translating device | Expired / Lapsed | 1951-11-15 | 1955-02-22 | 0 | Details |
| US2702760A | Method of applying metallic stripes to a web of paper | Expired / Lapsed | 1951-04-25 | 1955-02-22 | 2 | Details |
| US2702186A | Accelerometer | Expired / Lapsed | 1947-07-07 | 1955-02-15 | 0 | Details |
| US2701357A | Capacitive commutator transmitter | Expired / Lapsed | 1950-12-22 | 1955-02-01 | 0 | Details |
| US2701326A | Semiconductor translating device | Expired / Lapsed | 1949-12-30 | 1955-02-01 | 0 | Details |
| US2701309A | Semiconductor oscillation generator | Expired / Lapsed | 1948-12-24 | 1955-02-01 | 0 | Details |
| US2699529A | Electronic timer | Expired / Lapsed | 1949-08-26 | 1955-01-11 | 0 | Details |
| US2698879A | Class of service determining circuit | Expired / Lapsed | 1949-11-30 | 1955-01-04 | 0 | Details |
| US2698414A | Current supply apparatus | Expired / Lapsed | 1952-03-05 | 1954-12-28 | 0 | Details |
| US2697269A | Method of making semiconductor translating devices | Expired / Lapsed | 1950-07-24 | 1954-12-21 | 1 | Details |
| US2696599A | Check circuits | Expired / Lapsed | 1953-02-12 | 1954-12-07 | 0 | Details |
| US2696529A | Voice-operated switching system | Expired / Lapsed | 1950-09-02 | 1954-12-07 | 0 | Details |
| US2695422A | Apparatus for advancing and working elastomer compounds | Expired / Lapsed | 1951-12-12 | 1954-11-30 | 0 | Details |
| US2695398A | Ferroelectric storage circuits | Expired / Lapsed | 1953-06-16 | 1954-11-23 | 0 | Details |
| US2694040A | Methods of selectively plating p-type material of a semicon… | Expired / Lapsed | 1951-12-28 | 1954-11-09 | 2 | Details |
| US2694140A | Selection of low interference radio channels | Expired / Lapsed | 1951-11-24 | 1954-11-09 | 0 | Details |
| US2694050A | Thermally sensitive resistor | Expired / Lapsed | 1949-09-01 | 1954-11-09 | 0 | Details |
| US2694160A | Expandable straight line trajectory radar and sonar indicat… | Expired / Lapsed | 1948-08-31 | 1954-11-09 | 0 | Details |
| US2693572A | Current and voltage regulation | Expired / Lapsed | 1953-03-31 | 1954-11-02 | 0 | Details |
| US2693568A | Current and voltage regulation | Expired / Lapsed | 1952-03-05 | 1954-11-02 | 0 | Details |
| US2692839A | Method of fabricating germanium bodies | Expired / Lapsed | 1951-03-07 | 1954-10-26 | 2 | Details |
| US2692961A | Isothermal electromagnetic apparatus | Expired / Lapsed | 1950-12-12 | 1954-10-26 | 0 | Details |
| US2692303A | Speech interpolated communication system | Expired / Lapsed | 1950-12-19 | 1954-10-19 | 0 | Details |
| US2692336A | Aperture antenna | Expired / Lapsed | 1949-11-26 | 1954-10-19 | 0 | Details |
| US2691736A | Electrical translation device, including semiconductor | Expired / Lapsed | 1950-12-27 | 1954-10-12 | 0 | Details |
| US2691738A | Electrical device embodying ferroelectric lanthanum-contain… | Expired / Lapsed | 1949-04-08 | 1954-10-12 | 2 | Details |
| US2689399A | Plated article and method of making it | Expired / Lapsed | 1950-12-05 | 1954-09-21 | 2 | Details |
| US2688582A | Method of forming laminated sheets | Expired / Lapsed | 1952-07-31 | 1954-09-07 | 2 | Details |
| US2688110A | Semiconductor translating device | Expired / Lapsed | 1950-11-30 | 1954-08-31 | 0 | Details |
| US2686843A | Call distributing service desk | Expired / Lapsed | 1951-04-26 | 1954-08-17 | 0 | Details |
| US2686838A | Translator | Expired / Lapsed | 1950-04-06 | 1954-08-17 | 0 | Details |
| US2685063A | Method of and system for measuring phase shift | Expired / Lapsed | 1952-10-20 | 1954-07-27 | 0 | Details |
| US2683794A | Infrared energy source | Expired / Lapsed | 1951-12-27 | 1954-07-13 | 0 | Details |
| US2683676A | Production of germanium rods having longitudinal crystal bo… | Expired / Lapsed | 1950-01-13 | 1954-07-13 | 2 | Details |
| US2683238A | Microwave amplifier | Expired / Lapsed | 1949-06-17 | 1954-07-06 | 0 | Details |
| US2682063A | Wiring tool | Expired / Lapsed | 1951-06-30 | 1954-06-29 | 0 | Details |
| US2682575A | Time division multiplex system | Expired / Lapsed | 1944-10-19 | 1954-06-29 | 0 | Details |
| US2682003A | Accelerometer | Expired / Lapsed | 1950-11-28 | 1954-06-22 | 0 | Details |
| US2681993A | Circuit element utilizing semiconductive materials | Expired / Lapsed | 1949-05-05 | 1954-06-22 | 0 | Details |
| US2680162A | Automatic line testing and switching circuit | Expired / Lapsed | 1953-02-06 | 1954-06-01 | 0 | Details |
| US2680160A | Bias circuit for transistor amplifiers | Expired / Lapsed | 1951-09-15 | 1954-06-01 | 0 | Details |
| US2679633A | Wave transmission network utilizing impedance inversion | Expired / Lapsed | 1952-10-22 | 1954-05-25 | 0 | Details |
| US2679551A | Capacitative commutator | Expired / Lapsed | 1950-09-21 | 1954-05-25 | 0 | Details |
| US2678997A | Pulse transmission | Expired / Lapsed | 1949-12-31 | 1954-05-18 | 0 | Details |
| US2678435A | Signal sender comprising motor driven capacitative commutat… | Expired / Lapsed | 1950-09-27 | 1954-05-11 | 0 | Details |
| US2677726A | Signaling system for carrier telephone transmission | Expired / Lapsed | 1950-07-26 | 1954-05-04 | 0 | Details |
| US2677019A | Magnetic head and method of making same | Expired / Lapsed | 1951-12-22 | 1954-04-27 | 0 | Details |
| US2677011A | Teletypewriter message identification system | Expired / Lapsed | 1950-09-12 | 1954-04-27 | 0 | Details |
| US2676271A | Transistor gate | Expired / Lapsed | 1952-01-25 | 1954-04-20 | 0 | Details |
| US2676206A | Computation and display of correlation | Expired / Lapsed | 1951-12-06 | 1954-04-20 | 0 | Details |
| US2676228A | Conditioning of semiconductor translators | Expired / Lapsed | 1951-10-06 | 1954-04-20 | 0 | Details |
| US2675427A | Electrostatic scanning mechanism for scanning both tips and… | Expired / Lapsed | 1951-12-21 | 1954-04-13 | 0 | Details |
| US2675499A | Cathode-ray device | Expired / Lapsed | 1948-07-10 | 1954-04-13 | 0 | Details |
| US2674659A | Magnetic head and method of making same | Expired / Lapsed | 1951-11-02 | 1954-04-06 | 0 | Details |
| US2673936A | Diode gate | Expired / Lapsed | 1952-04-28 | 1954-03-30 | 0 | Details |
| US2672508A | Teletypewriter line feed transmitting and counting apparatus | Expired / Lapsed | 1950-10-04 | 1954-03-16 | 0 | Details |
| US2672590A | Delay line | Expired / Lapsed | 1950-03-22 | 1954-03-16 | 0 | Details |
| US2672515A | Calling station identification circuit | Expired / Lapsed | 1950-01-28 | 1954-03-16 | 0 | Details |
| US2672528A | Semiconductor translating device | Expired / Lapsed | 1949-05-28 | 1954-03-16 | 0 | Details |
| US2671739A | Plating with sulfides, selenides, and tellurides of chromiu… | Expired / Lapsed | 1949-06-22 | 1954-03-09 | 2 | Details |
| US2670445A | Regenerative transistor amplifier | Expired / Lapsed | 1951-11-06 | 1954-02-23 | 0 | Details |
| US2670435A | Radiotelephone communication system | Expired / Lapsed | 1951-02-02 | 1954-02-23 | 0 | Details |
| US2670441A | Alpha particle counter | Expired / Lapsed | 1949-09-07 | 1954-02-23 | 0 | Details |
| US2669635A | Semiconductive photoelectric transducer | Expired / Lapsed | 1952-11-13 | 1954-02-16 | 0 | Details |
| US2669654A | Limiter amplifier circuit | Expired / Lapsed | 1950-06-27 | 1954-02-16 | 0 | Details |
| US2669706A | Code selector | Expired / Lapsed | 1950-05-09 | 1954-02-16 | 0 | Details |
| US2668877A | Electromechanical translator | Expired / Lapsed | 1947-11-04 | 1954-02-09 | 0 | Details |
| US2667970A | Automatic limit bridge | Expired / Lapsed | 1948-09-01 | 1954-02-02 | 0 | Details |
| US2667607A | Semiconductor circuit element | Expired / Lapsed | 1952-04-26 | 1954-01-26 | 0 | Details |
| US2667260A | Conveyer system | Expired / Lapsed | 1948-09-11 | 1954-01-26 | 0 | Details |
| US2666819A | Balanced amplifier employing transistors of complementary c… | Expired / Lapsed | 1951-09-18 | 1954-01-19 | 0 | Details |
| US2666818A | Transistor amplifier | Expired / Lapsed | 1951-09-13 | 1954-01-19 | 0 | Details |
| US2666356A | Servo system for nonintermittent film projectors | Expired / Lapsed | 1950-06-13 | 1954-01-19 | 0 | Details |
| US2665845A | Transistor trigger circuit for operating relays | Expired / Lapsed | 1952-10-08 | 1954-01-12 | 0 | Details |
| US2666196A | Frequency station calling system using bifurcated piezoelec… | Expired / Lapsed | 1949-06-07 | 1954-01-12 | 0 | Details |
| US2663857A | Curve follower | Expired / Lapsed | 1951-10-25 | 1953-12-22 | 0 | Details |
| US2663766A | Transistor amplifier with conjugate input and output circui… | Expired / Lapsed | 1950-06-28 | 1953-12-22 | 0 | Details |
| US2662997A | Mounting for semiconductors | Expired / Lapsed | 1951-11-23 | 1953-12-15 | 2 | Details |
| US2662120A | Magnetic head | Expired / Lapsed | 1950-02-18 | 1953-12-08 | 0 | Details |
| US2662122A | Two-way transistor electrical transmission system | Expired / Lapsed | 1949-06-01 | 1953-12-08 | 0 | Details |
| US2662124A | Transistor amplifier circuit | Expired / Lapsed | 1949-06-01 | 1953-12-08 | 0 | Details |
| US2660680A | Crystal temperature control means | Expired / Lapsed | 1950-08-09 | 1953-11-24 | 0 | Details |
| US2660676A | Signal generating device | Expired / Lapsed | 1950-02-15 | 1953-11-24 | 0 | Details |
| US2659813A | Frequency modulation repeater | Expired / Lapsed | 1950-02-11 | 1953-11-17 | 0 | Details |
| US2658114A | Magnetic recording-reproducing device | Expired / Lapsed | 1952-08-26 | 1953-11-03 | 0 | Details |
| US2658188A | Pulse position dialing system with direct time measuring ap… | Expired / Lapsed | 1948-06-29 | 1953-11-03 | 0 | Details |
| US2657318A | Electronic switch | Expired / Lapsed | 1952-03-22 | 1953-10-27 | 0 | Details |
| US2657378A | Pulse translation apparatus | Expired / Lapsed | 1951-05-25 | 1953-10-27 | 0 | Details |
| US2657377A | Reproduction of signals from magnetic records | Expired / Lapsed | 1951-05-25 | 1953-10-27 | 0 | Details |
| US2657272A | Electronic induction translator | Expired / Lapsed | 1951-03-03 | 1953-10-27 | 0 | Details |
| US2657307A | Positive feedback pulse generator | Expired / Lapsed | 1950-07-01 | 1953-10-27 | 0 | Details |
| US2656496A | Semiconductor translating device | Expired / Lapsed | 1951-07-31 | 1953-10-20 | 0 | Details |
| US2656404A | Laminated ring lead-in for electron discharge devices | Expired / Lapsed | 1950-12-01 | 1953-10-20 | 0 | Details |
| US2655690A | Method of and apparatus for continuously making vulcanized … | Expired / Lapsed | 1950-08-09 | 1953-10-20 | 0 | Details |
| US2656460A | Bidirectional counter | Expired / Lapsed | 1949-10-28 | 1953-10-20 | 0 | Details |
| US2655646A | Supervisory alarm system | Expired / Lapsed | 1952-08-14 | 1953-10-13 | 0 | Details |
| US2655608A | Semiconductor circuit controlling device | Expired / Lapsed | 1952-07-22 | 1953-10-13 | 0 | Details |
| US2655610A | Semiconductor signal translating device | Expired / Lapsed | 1952-07-22 | 1953-10-13 | 0 | Details |
| US2655609A | Bistable circuits, including transistors | Expired / Lapsed | 1952-07-22 | 1953-10-13 | 0 | Details |
| US2655625A | Semiconductor circuit element | Expired / Lapsed | 1952-04-26 | 1953-10-13 | 0 | Details |
| US2654059A | Semiconductor signal translating device | Expired / Lapsed | 1951-05-26 | 1953-09-29 | 0 | Details |
| US2652460A | Transistor amplifier circuits | Expired / Lapsed | 1950-09-12 | 1953-09-15 | 0 | Details |
| US2651021A | Fault detector | Expired / Lapsed | 1951-04-20 | 1953-09-01 | 0 | Details |
| US2649574A | Hall-effect wave translating device | Expired / Lapsed | 1951-04-05 | 1953-08-18 | 0 | Details |
| US2649569A | Semiconductor magnetoresistive device | Expired / Lapsed | 1950-09-28 | 1953-08-18 | 0 | Details |
| US2649570A | Test equipment and method for measuring reflection coeffici… | Expired / Lapsed | 1950-06-29 | 1953-08-18 | 0 | Details |
| US2649568A | Magnetometer | Expired / Lapsed | 1949-07-12 | 1953-08-18 | 0 | Details |
| US2648589A | Magnetic recorder | Expired / Lapsed | 1949-07-19 | 1953-08-11 | 0 | Details |
| US2647958A | Voltage and current bias of transistors | Expired / Lapsed | 1949-10-25 | 1953-08-04 | 0 | Details |
| US2647957A | Transistor circuit | Expired / Lapsed | 1949-06-01 | 1953-08-04 | 0 | Details |
| US2645700A | Semiconductor of mixed nickel, manganese, and iron oxides | Expired / Lapsed | 1949-08-27 | 1953-07-14 | 2 | Details |
| US2643632A | Coaxial dial locking device | Expired / Lapsed | 1950-10-06 | 1953-06-30 | 0 | Details |
| US2641800A | Apparatus for advancing and working plastic compounds | Expired / Lapsed | 1951-06-21 | 1953-06-16 | 0 | Details |
| US2642493A | Automatic message accounting system | Expired / Lapsed | 1947-02-27 | 1953-06-16 | 0 | Details |
| US2641713A | Semiconductor photoelectric device | Expired / Lapsed | 1951-03-21 | 1953-06-09 | 0 | Details |
| US2640137A | Temperature control system | Expired / Lapsed | 1950-11-15 | 1953-05-26 | 0 | Details |
| US2635810A | Multicathode gaseous discharge device and circuits | Expired / Lapsed | 1952-02-15 | 1953-04-21 | 0 | Details |
| US2635975A | Method of bonding polyethylene to vulcanized rubber and art… | Expired / Lapsed | 1951-02-27 | 1953-04-21 | 4 | Details |
| US2636133A | Diode gate | Expired / Lapsed | 1950-12-01 | 1953-04-21 | 0 | Details |
| US2636081A | Supervisory circuits for pulse code modulation | Expired / Lapsed | 1950-07-27 | 1953-04-21 | 0 | Details |
| US2636080A | Balanced diode clamper circuit for low-frequency restoration | Expired / Lapsed | 1949-01-26 | 1953-04-21 | 0 | Details |
| US2636125A | Selective electromagnetic wave system | Expired / Lapsed | 1948-04-10 | 1953-04-21 | 0 | Details |
| US2636135A | Stress-coupled core and crystal transformer | Expired / Lapsed | 1947-10-29 | 1953-04-21 | 0 | Details |
| US2635146A | Speech analyzing and synthesizing communication system | Expired / Lapsed | 1949-12-15 | 1953-04-14 | 0 | Details |
| US2634413A | Velocity measuring system utilizing radio technique | Expired / Lapsed | 1948-04-08 | 1953-04-07 | 0 | Details |
| US2632101A | Reduction of noise in transmission systems | Expired / Lapsed | 1950-10-23 | 1953-03-17 | 0 | Details |
| US2632062A | Semiconductor transducer | Expired / Lapsed | 1949-06-15 | 1953-03-17 | 0 | Details |
| US2632058A | Pulse code communication | Expired / Lapsed | 1947-11-13 | 1953-03-17 | 0 | Details |
| US2632057A | Signal transmission | Expired / Lapsed | 1944-04-12 | 1953-03-17 | 0 | Details |
| US2630482A | Tuned vibrating reed selective circuit | Expired / Lapsed | 1948-07-10 | 1953-03-03 | 0 | Details |
| US2629834A | Gate and trigger circuits employing transistors | Expired / Lapsed | 1951-09-15 | 1953-02-24 | 0 | Details |
| US2629833A | Transistor trigger circuits | Expired / Lapsed | 1951-04-28 | 1953-02-24 | 0 | Details |
| US2629672A | Method of making semiconductive translating devices | Expired / Lapsed | 1949-07-07 | 1953-02-24 | 1 | Details |
| US2629010A | Television system having reduced transmission bandwidth | Expired / Lapsed | 1949-12-30 | 1953-02-17 | 0 | Details |
| US2628999A | Continuity, polarity, and breakdown test device | Expired / Lapsed | 1949-04-07 | 1953-02-17 | 0 | Details |
| US2627769A | Swaging pliers for electrical connections | Expired / Lapsed | 1949-01-12 | 1953-02-10 | 0 | Details |
| US2628263A | Quick detachable connector for interconnecting terminals | Expired / Lapsed | 1948-12-24 | 1953-02-10 | 0 | Details |
| US2626983A | Magnetic testing apparatus | Expired / Lapsed | 1951-03-06 | 1953-01-27 | 0 | Details |
| US2627039A | Gating circuits | Expired / Lapsed | 1950-05-29 | 1953-01-27 | 0 | Details |
| US2626448A | Apparatus for and method of treating selenium rectifiers | Expired / Lapsed | 1947-08-26 | 1953-01-27 | 0 | Details |
| US2623105A | Semiconductor translating device having controlled gain | Expired / Lapsed | 1951-09-21 | 1952-12-23 | 0 | Details |
| US2623102A | Circuit element utilizing semiconductive materials | Expired / Lapsed | 1949-05-05 | 1952-12-23 | 0 | Details |
| US2622213A | Transistor circuit for pulse amplifier delay and the like | Expired / Lapsed | 1951-09-19 | 1952-12-16 | 0 | Details |
| US2622212A | Bistable circuit | Expired / Lapsed | 1951-09-15 | 1952-12-16 | 0 | Details |
| US2622211A | Stabilized transistor trigger circuit | Expired / Lapsed | 1951-04-28 | 1952-12-16 | 0 | Details |
| US2622127A | Indicating apparatus | Expired / Lapsed | 1948-12-14 | 1952-12-16 | 0 | Details |
| US2621295A | Electrical wave producing circuit | Expired / Lapsed | 1949-02-15 | 1952-12-09 | 0 | Details |
| US2620448A | Transistor trigger circuits | Expired / Lapsed | 1950-09-12 | 1952-12-02 | 0 | Details |
| US2618686A | Distortion indicator | Expired / Lapsed | 1948-03-01 | 1952-11-18 | 0 | Details |
| US2617865A | Semiconductor amplifier and electrode structures therefor | Expired / Lapsed | 1949-09-15 | 1952-11-11 | 0 | Details |
| US2617704A | Recording system | Expired / Lapsed | 1947-07-15 | 1952-11-11 | 0 | Details |
| US2616971A | Automatic volume control | Expired / Lapsed | 1949-03-05 | 1952-11-04 | 0 | Details |
| US2616627A | Counter circuit | Expired / Lapsed | 1948-10-06 | 1952-11-04 | 0 | Details |
| US2616625A | Electrical computing system | Expired / Lapsed | 1946-07-26 | 1952-11-04 | 0 | Details |
| US2616060A | Cathode-ray coding tube | Expired / Lapsed | 1948-07-03 | 1952-10-28 | 0 | Details |
| US2614140A | Trigger circuit | Expired / Lapsed | 1950-05-26 | 1952-10-14 | 0 | Details |
| US2614141A | Counting circuit | Expired / Lapsed | 1950-05-26 | 1952-10-14 | 0 | Details |
| US2614211A | Frequency controlled radio relaying system | Expired / Lapsed | 1950-05-13 | 1952-10-14 | 0 | Details |
| US2612566A | Magnetic recording and reproducing system | Expired / Lapsed | 1951-06-05 | 1952-09-30 | 0 | Details |
| US2612561A | Half-duplex telegraph repeater | Expired / Lapsed | 1949-10-25 | 1952-09-30 | 0 | Details |
| US2610297A | Automatic frequency control circuit | Expired / Lapsed | 1948-12-14 | 1952-09-09 | 0 | Details |
| US2608674A | Multicathode glow discharge device | Expired / Lapsed | 1951-02-09 | 1952-08-26 | 0 | Details |
| US2608617A | Television converter system | Expired / Lapsed | 1950-06-14 | 1952-08-26 | 0 | Details |
| US2608539A | Metallized ceramic coating composition | Expired / Lapsed | 1950-03-22 | 1952-08-26 | 2 | Details |
| US2608610A | Transformer | Expired / Lapsed | 1950-01-28 | 1952-08-26 | 0 | Details |
| US2608621A | Magnetic record detector | Expired / Lapsed | 1949-10-08 | 1952-08-26 | 0 | Details |
| US2608623A | Wave transmission amplifier | Expired / Lapsed | 1949-06-18 | 1952-08-26 | 0 | Details |
| US2607891A | Translating circuits utilizing glow discharge devices | Expired / Lapsed | 1950-06-10 | 1952-08-19 | 0 | Details |
| US2607272A | Composite wave plate for light | Expired / Lapsed | 1949-02-11 | 1952-08-19 | 0 | Details |
| US2607843A | Remote control and supervisory system | Expired / Lapsed | 1948-11-12 | 1952-08-19 | 0 | Details |
| US2606960A | Semiconductor translating device | Expired / Lapsed | 1949-06-01 | 1952-08-12 | 0 | Details |
| US2606288A | Timing pulse generator | Expired / Lapsed | 1950-10-04 | 1952-08-05 | 0 | Details |
| US2605361A | Differential quantization of communication signals | Expired / Lapsed | 1950-06-29 | 1952-07-29 | 0 | Details |
| US2603694A | Semiconductor signal translating device | Expired / Lapsed | 1951-05-05 | 1952-07-15 | 0 | Details |
| US2603693A | Semiconductor signal translating device | Expired / Lapsed | 1950-10-10 | 1952-07-15 | 0 | Details |
| US2603716A | Decoder and translator with readily changeable translations | Expired / Lapsed | 1949-12-23 | 1952-07-15 | 0 | Details |
| US2603715A | Pulse position call or dial receiver | Expired / Lapsed | 1948-06-29 | 1952-07-15 | 0 | Details |
| US2603692A | Rectifier and method of making it | Expired / Lapsed | 1948-05-22 | 1952-07-15 | 0 | Details |
| US2602872A | Apparatus for equipping crystals with wires | Expired / Lapsed | 1948-12-30 | 1952-07-08 | 0 | Details |
| US2602763A | Preparation of semiconductive materials for translating dev… | Expired / Lapsed | 1948-12-29 | 1952-07-08 | 2 | Details |
| US2602853A | Selective signaling system | Expired / Lapsed | 1947-08-08 | 1952-07-08 | 0 | Details |
| US2602211A | Rectifier and method of making it | Expired / Lapsed | 1945-12-29 | 1952-07-08 | 0 | Details |
| US2602033A | Carbonyl process | Expired / Lapsed | 1950-01-18 | 1952-07-01 | 2 | Details |
| US2602148A | High-frequency amplifier | Expired / Lapsed | 1946-10-22 | 1952-07-01 | 0 | Details |
| US2601415A | Vertical sweep synchronizing circuit | Expired / Lapsed | 1949-06-30 | 1952-06-24 | 0 | Details |
| US2601403A | Electric circuit | Expired / Lapsed | 1948-03-19 | 1952-06-24 | 0 | Details |
| US2600500A | Semiconductor signal translating device with controlled car… | Expired / Lapsed | 1948-09-24 | 1952-06-17 | 0 | Details |
| US2600482A | Electric delay circuit | Expired / Lapsed | 1948-05-13 | 1952-06-17 | 0 | Details |
| US2600466A | Wave guide attenuator | Expired / Lapsed | 1943-05-07 | 1952-06-17 | 0 | Details |
| US2599746A | Endless conveyer for supporting conductors or cables in vul… | Expired / Lapsed | 1949-11-30 | 1952-06-10 | 0 | Details |
| US2598677A | Multicathode glow discharge device | Expired / Lapsed | 1949-12-15 | 1952-06-03 | 0 | Details |
| US2599097A | Radiotelephone station identifying system | Expired / Lapsed | 1948-12-30 | 1952-06-03 | 0 | Details |
| US2599368A | Beam switching system | Expired / Lapsed | 1948-05-10 | 1952-06-03 | 0 | Details |
| US2599392A | Recording device | Expired / Lapsed | 1947-09-05 | 1952-06-03 | 0 | Details |
| US2597428A | Checking means for pulse counting circuit | Expired / Lapsed | 1951-03-31 | 1952-05-20 | 0 | Details |
| US2597028A | Semiconductor signal translating device | Expired / Lapsed | 1949-11-30 | 1952-05-20 | 0 | Details |
| US2596199A | Error correction in sequential code pulse transmission | Expired / Lapsed | 1951-02-19 | 1952-05-13 | 0 | Details |
| US2595667A | Sweep circuit | Expired / Lapsed | 1949-12-24 | 1952-05-06 | 0 | Details |
| US2595701A | Recording system | Expired / Lapsed | 1948-12-31 | 1952-05-06 | 0 | Details |
| US2595646A | Television test signal generator | Expired / Lapsed | 1947-06-02 | 1952-05-06 | 0 | Details |
| US2594449A | Transistor switching device | Expired / Lapsed | 1950-12-30 | 1952-04-29 | 0 | Details |
| US2595208A | Transistor pulse divider | Expired / Lapsed | 1950-12-29 | 1952-04-29 | 0 | Details |
| US2594336A | Electrical counter circuit | Expired / Lapsed | 1950-10-17 | 1952-04-29 | 0 | Details |
| US2594530A | Amplifying system | Expired / Lapsed | 1948-10-02 | 1952-04-29 | 0 | Details |
| US2594389A | Double-lockout interconnecting system | Expired / Lapsed | 1948-08-04 | 1952-04-29 | 0 | Details |
| US2594495A | Magnetic recording system for call data in automatic teleph… | Expired / Lapsed | 1947-09-04 | 1952-04-29 | 0 | Details |
| US2595106A | Recording telephone system | Expired / Lapsed | 1947-06-18 | 1952-04-29 | 0 | Details |
| US2592683A | Storage device utilizing semiconductor | Expired / Lapsed | 1950-12-30 | 1952-04-15 | 0 | Details |
| US2592652A | Magnetic transducer head | Expired / Lapsed | 1950-02-18 | 1952-04-15 | 0 | Details |
| US2592549A | Anode structure for electron discharge devices | Expired / Lapsed | 1949-08-03 | 1952-04-15 | 0 | Details |
| US2592308A | Nonlinear pulse code modulation system | Expired / Lapsed | 1948-09-01 | 1952-04-08 | 0 | Details |
| US2592228A | Decoder for pulse code modulation receivers | Expired / Lapsed | 1947-07-07 | 1952-04-08 | 0 | Details |
| US2591557A | Apparatus for dipping articles in liquid | Expired / Lapsed | 1949-10-05 | 1952-04-01 | 0 | Details |
| US2589704A | Semiconductor signal translating device | Expired / Lapsed | 1950-08-03 | 1952-03-18 | 0 | Details |
| US2589800A | Telephone signaling system | Expired / Lapsed | 1950-05-19 | 1952-03-18 | 0 | Details |
| US2589711A | Off-channel squelch circuit for radio receivers | Expired / Lapsed | 1948-05-05 | 1952-03-18 | 0 | Details |
| US2589130A | Permutation code group selector | Expired / Lapsed | 1949-06-24 | 1952-03-11 | 0 | Details |
| US2587014A | Charge and tax determining equipment for telephone systems | Expired / Lapsed | 1948-12-29 | 1952-02-26 | 0 | Details |
| US2586080A | Semiconductive signal translating device | Expired / Lapsed | 1949-10-11 | 1952-02-19 | 0 | Details |
| US2585904A | Crossbar telephone system | Expired / Lapsed | 1948-10-29 | 1952-02-19 | 0 | Details |
| US2585890A | Delay-action filter circuit | Expired / Lapsed | 1949-10-22 | 1952-02-12 | 0 | Details |
| US2585722A | Frequency divider | Expired / Lapsed | 1949-10-06 | 1952-02-12 | 0 | Details |
| US2584990A | Transitor counting system | Expired / Lapsed | 1949-03-26 | 1952-02-12 | 0 | Details |
| US2585077A | Control of impedance of semiconductor amplifier circuits | Expired / Lapsed | 1948-11-06 | 1952-02-12 | 0 | Details |
| US2585078A | Negative resistance device utilizing semiconductor amplifier | Expired / Lapsed | 1948-11-06 | 1952-02-12 | 0 | Details |
| US2584736A | Telegraph switching system | Expired / Lapsed | 1950-05-02 | 1952-02-05 | 0 | Details |
| US2583088A | Alarm signaling system | Expired / Lapsed | 1950-09-13 | 1952-01-22 | 0 | Details |
| US2582959A | Electron-tube controlled switching system | Expired / Lapsed | 1947-10-29 | 1952-01-22 | 0 | Details |
| US2582481A | Temperature-controlled soldering iron | Expired / Lapsed | 1950-12-16 | 1952-01-15 | 0 | Details |
| US2582498A | Negative impedance repeater and loading system | Expired / Lapsed | 1949-08-30 | 1952-01-15 | 0 | Details |
| US2580685A | Color television with reduced band width | Expired / Lapsed | 1949-12-30 | 1952-01-01 | 0 | Details |
| US2580668A | Elastomer mold sealing device | Expired / Lapsed | 1949-04-16 | 1952-01-01 | 0 | Details |
| US2580673A | Saw-tooth generator and system utilizing it | Expired / Lapsed | 1947-11-14 | 1952-01-01 | 0 | Details |
| US2580083A | Contrast pattern generator | Expired / Lapsed | 1947-10-08 | 1951-12-25 | 0 | Details |
| US2579336A | Stabilized transistor trigger circuit | Expired / Lapsed | 1950-09-15 | 1951-12-18 | 0 | Details |
| US2579302A | Decoder for pulse code modulation | Expired / Lapsed | 1948-01-17 | 1951-12-18 | 0 | Details |
| US2577151A | Regulated rectifying apparatus | Expired / Lapsed | 1949-10-11 | 1951-12-04 | 0 | Details |
| US2577137A | Time-delay circuit | Expired / Lapsed | 1947-09-09 | 1951-12-04 | 0 | Details |
| US2577619A | Metallic structure for delaying unipolarized waves | Expired / Lapsed | 1947-05-16 | 1951-12-04 | 0 | Details |
| US2576267A | Preparation of germanium rectifier material | Expired / Lapsed | 1948-10-27 | 1951-11-27 | 2 | Details |
| US2576026A | Electronic switch | Expired / Lapsed | 1950-06-28 | 1951-11-20 | 0 | Details |
| US2575990A | Automatic volume control | Expired / Lapsed | 1949-12-31 | 1951-11-20 | 0 | Details |
| US2575910A | Voice-operated signaling system | Expired / Lapsed | 1949-09-21 | 1951-11-20 | 0 | Details |
| US2576040A | Cathode-ray device | Expired / Lapsed | 1948-03-10 | 1951-11-20 | 0 | Details |
| US2575383A | High-frequency amplifying device | Expired / Lapsed | 1946-10-22 | 1951-11-20 | 0 | Details |
| US2573744A | Regulated current supply apparatus | Expired / Lapsed | 1949-06-11 | 1951-11-06 | 0 | Details |
| US2573150A | Frequency divider | Expired / Lapsed | 1946-02-28 | 1951-10-30 | 0 | Details |
| US2572586A | Sweep circuit | Expired / Lapsed | 1950-03-18 | 1951-10-23 | 0 | Details |
| US2572132A | Transcribing and summarizing system | Expired / Lapsed | 1949-04-27 | 1951-10-23 | 0 | Details |
| US2571680A | Pulse code modulation system employing code substitution | Expired / Lapsed | 1949-02-11 | 1951-10-16 | 0 | Details |
| US2570225A | Series electronic switch | Expired / Lapsed | 1950-03-13 | 1951-10-09 | 0 | Details |
| US2570978A | Semiconductor translating device | Expired / Lapsed | 1949-10-11 | 1951-10-09 | 0 | Details |
| US2569347A | Circuit element utilizing semiconductive material | Expired / Lapsed | 1948-06-26 | 1951-09-25 | 0 | Details |
| US2567812A | Code transmitter | Expired / Lapsed | 1948-03-26 | 1951-09-11 | 0 | Details |
| US2566846A | Apparatus for insulating conductors | Expired / Lapsed | 1949-03-30 | 1951-09-04 | 0 | Details |
| US2566426A | Relay selecting and indicating circuit | Expired / Lapsed | 1948-12-18 | 1951-09-04 | 0 | Details |
| US2564784A | Condenser | Expired / Lapsed | 1948-11-06 | 1951-08-21 | 0 | Details |
| US2564010A | Unattended repeater testing by causing the repeaters to osc… | Expired / Lapsed | 1947-07-07 | 1951-08-14 | 0 | Details |
| US2564419A | Time division multiplex system for signals of different ban… | Expired / Lapsed | 1947-04-14 | 1951-08-14 | 0 | Details |
| US2564439A | Standard frequency system | Expired / Lapsed | 1946-10-30 | 1951-08-14 | 0 | Details |
| US2562277A | Metallic lens directive antenna system | Expired / Lapsed | 1946-04-08 | 1951-07-31 | 0 | Details |
| US2562281A | Directive pickup for transmission lines | Expired / Lapsed | 1944-06-14 | 1951-07-31 | 0 | Details |
| US2561411A | Semiconductor signal translating device | Expired / Lapsed | 1950-03-08 | 1951-07-24 | 0 | Details |
| US2561476A | Magnetic recorder | Expired / Lapsed | 1947-09-29 | 1951-07-24 | 0 | Details |
| US2560594A | Semiconductor translator and method of making it | Expired / Lapsed | 1948-09-24 | 1951-07-17 | 0 | Details |
| US2560792A | Electrolytic surface treatment of germanium | Expired / Lapsed | 1948-02-26 | 1951-07-17 | 0 | Details |
| US2561196A | Soldering fixture | Expired / Lapsed | 1947-01-21 | 1951-07-17 | 0 | Details |
| US2558187A | Selective signaling generator in which coded information is… | Expired / Lapsed | 1949-12-15 | 1951-06-26 | 0 | Details |
| US2556296A | High-frequency transistor oscillator | Expired / Lapsed | 1949-04-26 | 1951-06-12 | 0 | Details |
| US2556286A | Oscillation generator | Expired / Lapsed | 1948-12-29 | 1951-06-12 | 0 | Details |
| US2556276A | Apparatus for simultaneously advancing and working organic … | Expired / Lapsed | 1947-11-28 | 1951-06-12 | 2 | Details |
| US2556711A | Method of producing rectifiers and rectifier material | Expired / Lapsed | 1947-10-29 | 1951-06-12 | 0 | Details |
| US2556964A | Ground trainer for aircraft personnel | Expired / Lapsed | 1945-11-16 | 1951-06-12 | 0 | Details |
| US2555959A | Nonlinear reactance circuits utilizing high dielectric cons… | Expired / Lapsed | 1946-10-18 | 1951-06-05 | 0 | Details |
| US2554549A | Recorder failure indicator | Expired / Lapsed | 1948-10-29 | 1951-05-29 | 0 | Details |
| US2554834A | Coupling for telephone receivers and hearing aid sets | Expired / Lapsed | 1948-06-29 | 1951-05-29 | 0 | Details |
| US2555001A | Bonded article and method of bonding | Expired / Lapsed | 1947-02-04 | 1951-05-29 | 0 | Details |
| US2553749A | Sealing fixture for the manufacture of electron discharge d… | Expired / Lapsed | 1948-05-05 | 1951-05-22 | 0 | Details |
| US2554155A | Ground trainer for training aircraft crews | Expired / Lapsed | 1946-12-13 | 1951-05-22 | 0 | Details |
| US2552629A | Error-detecting and correcting system | Expired / Lapsed | 1950-01-11 | 1951-05-15 | 0 | Details |
| US2552619A | Electron beam coder for pulse code modulation | Expired / Lapsed | 1949-03-05 | 1951-05-15 | 0 | Details |
| US2553490A | Magnetic control of semiconductor currents | Expired / Lapsed | 1949-02-21 | 1951-05-15 | 0 | Details |
| US2553255A | Telephone substation apparatus | Expired / Lapsed | 1948-09-28 | 1951-05-15 | 0 | Details |
| US2552626A | Silicon-germanium resistor and method of making it | Expired / Lapsed | 1948-02-17 | 1951-05-15 | 2 | Details |
| US2550518A | Control of impedance of semiconductor amplifier circuits | Expired / Lapsed | 1949-11-15 | 1951-04-24 | 0 | Details |
| US2550555A | Apparatus for extruding materials on cores under vacuum | Expired / Lapsed | 1949-05-11 | 1951-04-24 | 0 | Details |
| US2550600A | Indicating circuit | Expired / Lapsed | 1948-11-22 | 1951-04-24 | 0 | Details |
| US2549872A | Focusing ultrasonic radiator | Expired / Lapsed | 1948-03-26 | 1951-04-24 | 0 | Details |
| US2550605A | Circuit closing device | Expired / Lapsed | 1945-07-25 | 1951-04-24 | 0 | Details |
| US2549422A | Decoder for multiple carrier pulse code modulation signals | Expired / Lapsed | 1949-01-06 | 1951-04-17 | 0 | Details |
| US2549505A | Phase or frequency modulation system | Expired / Lapsed | 1948-09-09 | 1951-04-17 | 0 | Details |
| US2549551A | Grid electrode structure and manufacturing method therefor | Expired / Lapsed | 1948-01-15 | 1951-04-17 | 0 | Details |
| US2548187A | Method of determining the oxygen content of copper | Expired / Lapsed | 1945-07-19 | 1951-04-10 | 2 | Details |
| US2547386A | Current storage device utilizing semiconductor | Expired / Lapsed | 1949-03-31 | 1951-04-03 | 0 | Details |
| US2547416A | Dielectric lens | Expired / Lapsed | 1946-12-19 | 1951-04-03 | 0 | Details |
| US2547539A | Signal wave duplexing system | Expired / Lapsed | 1946-06-27 | 1951-04-03 | 0 | Details |
| US2546316A | Synchronization of pulse communication systems | Expired / Lapsed | 1949-06-07 | 1951-03-27 | 0 | Details |
| US2546321A | Piezoelectric crystal apparatus | Expired / Lapsed | 1949-02-12 | 1951-03-27 | 0 | Details |
| US2546829A | Magnetic recorder and reproducer | Expired / Lapsed | 1948-12-18 | 1951-03-27 | 0 | Details |
| US2546840A | Wave guide phase shifter | Expired / Lapsed | 1945-04-26 | 1951-03-27 | 0 | Details |
| US2545551A | Automatic electronic detecting and testing apparatus for sw… | Expired / Lapsed | 1947-12-31 | 1951-03-20 | 0 | Details |
| US2544755A | Electron camera tube | Expired / Lapsed | 1948-01-29 | 1951-03-13 | 0 | Details |
| US2544753A | Electron camera tube | Expired / Lapsed | 1948-01-29 | 1951-03-13 | 0 | Details |
| US2544754A | Electron camera tube | Expired / Lapsed | 1948-01-29 | 1951-03-13 | 0 | Details |
| US2544330A | Selective signaling device | Expired / Lapsed | 1947-11-04 | 1951-03-06 | 0 | Details |
| US2542727A | Etching processes and solutions | Expired / Lapsed | 1949-12-29 | 1951-02-20 | 2 | Details |
| US2542672A | Coordinate selecting and lockout circuit | Expired / Lapsed | 1948-10-27 | 1951-02-20 | 0 | Details |
| US2542644A | Multistage ring circuit | Expired / Lapsed | 1948-09-01 | 1951-02-20 | 0 | Details |
| US2542183A | Transmission privacy synchronizing and equalizing system | Expired / Lapsed | 1948-07-10 | 1951-02-20 | 0 | Details |
| US2541322A | Control of impedance of semiconductor amplifier circuits | Expired / Lapsed | 1949-11-15 | 1951-02-13 | 0 | Details |
| US2541348A | Time division multiplex telephone system | Expired / Lapsed | 1948-07-24 | 1951-02-13 | 0 | Details |
| US2541932A | Multiplex speech interpolation system | Expired / Lapsed | 1948-05-19 | 1951-02-13 | 0 | Details |
| US2541910A | Directional coupler | Expired / Lapsed | 1947-09-18 | 1951-02-13 | 0 | Details |
| US2539623A | Communication system | Expired / Lapsed | 1947-02-12 | 1951-01-30 | 0 | Details |
| US2539535A | Source of electrical energy | Expired / Lapsed | 1946-03-16 | 1951-01-30 | 0 | Details |
| US2539556A | Variable delay speech privacy system | Expired / Lapsed | 1941-07-11 | 1951-01-30 | 0 | Details |
| US2538615A | Decoder for reflected binary codes | Expired / Lapsed | 1948-02-10 | 1951-01-16 | 0 | Details |
| US2538636A | Digital computer | Expired / Lapsed | 1947-12-31 | 1951-01-16 | 0 | Details |
| US2538266A | Communication system employing pulse code modulation | Expired / Lapsed | 1945-05-10 | 1951-01-16 | 0 | Details |
| US2537843A | Pulse regeneration apparatus | Expired / Lapsed | 1947-09-09 | 1951-01-09 | 0 | Details |
| US2537388A | Beam amplifier | Expired / Lapsed | 1947-05-14 | 1951-01-09 | 0 | Details |
| US2535303A | Electronic switch | Expired / Lapsed | 1949-10-21 | 1950-12-26 | 0 | Details |
| US2535400A | Multicontact dry reed relay | Expired / Lapsed | 1949-08-25 | 1950-12-26 | 0 | Details |
| US2534372A | Cathode-ray device | Expired / Lapsed | 1948-11-19 | 1950-12-19 | 0 | Details |
| US2534392A | Method of making glass window seals | Expired / Lapsed | 1946-07-08 | 1950-12-19 | 0 | Details |
| US2534862A | Radio ranging system with selective automatic volume contro… | Expired / Lapsed | 1942-06-23 | 1950-12-19 | 0 | Details |
| US2532125A | Selective station ringing system | Expired / Lapsed | 1949-01-28 | 1950-11-28 | 0 | Details |
| US2532098A | Automatic sound reproducing control system | Expired / Lapsed | 1948-03-23 | 1950-11-28 | 0 | Details |
| US2530538A | Vernier pulse code communication system | Expired / Lapsed | 1948-12-18 | 1950-11-21 | 0 | Details |
| US2530745A | Transistor microphone with conductive grains | Expired / Lapsed | 1948-12-10 | 1950-11-21 | 0 | Details |
| US2530890A | Radar antenna driving mechanism | Expired / Lapsed | 1947-07-26 | 1950-11-21 | 0 | Details |
| US2530824A | Secret carrier signaling method and system | Expired / Lapsed | 1946-08-20 | 1950-11-21 | 0 | Details |
| US2530693A | Panoramic signal receiving system | Expired / Lapsed | 1944-06-17 | 1950-11-21 | 0 | Details |
| US2527650A | Synchronization of pulse transmission systems | Expired / Lapsed | 1949-03-31 | 1950-10-31 | 0 | Details |
| US2527649A | Synchronization of pulse transmission systems | Expired / Lapsed | 1949-02-18 | 1950-10-31 | 0 | Details |
| US2527632A | Storage tube | Expired / Lapsed | 1948-01-29 | 1950-10-31 | 0 | Details |
| US2527652A | Storage tube | Expired / Lapsed | 1948-01-29 | 1950-10-31 | 0 | Details |
| US2528086A | Relay contacts of conducting rubber | Expired / Lapsed | 1946-11-08 | 1950-10-31 | 0 | Details |
| US2527136A | Fluid mixing apparatus | Expired / Lapsed | 1946-08-16 | 1950-10-24 | 0 | Details |
| US2527138A | Apparatus for making resistance measurements | Expired / Lapsed | 1945-03-08 | 1950-10-24 | 0 | Details |
| US2524035A | Three-electrode circuit element utilizing semiconductive ma… | Expired / Lapsed | 1948-06-17 | 1950-10-03 | 0 | Details |
| US2524034A | Three-electrode circuit element utilizing semiconductor mat… | Expired / Lapsed | 1948-02-26 | 1950-10-03 | 0 | Details |
| US2523365A | Testing system for cathode-ray telephone switching apparatus | Expired / Lapsed | 1948-05-10 | 1950-09-26 | 0 | Details |
| US2523904A | Record sensing and translating device | Expired / Lapsed | 1946-10-11 | 1950-09-26 | 0 | Details |
| US2522521A | Thermal transistor microphone | Expired / Lapsed | 1949-01-14 | 1950-09-19 | 0 | Details |
| US2522539A | Frequency control for synthesizing systems | Expired / Lapsed | 1948-07-02 | 1950-09-19 | 0 | Details |
| US2522259A | Electrode temperature regulation | Expired / Lapsed | 1948-05-06 | 1950-09-12 | 0 | Details |
| US2522130A | Carrier telegraph receiving circuit | Expired / Lapsed | 1947-06-19 | 1950-09-12 | 0 | Details |
| US2522291A | Cathode-ray tube with target controlled deflecting plates | Expired / Lapsed | 1945-09-20 | 1950-09-12 | 0 | Details |
| US2522000A | Recording telephone system | Expired / Lapsed | 1943-05-05 | 1950-09-12 | 0 | Details |
| US2521545A | Electron discharge device | Expired / Lapsed | 1946-06-28 | 1950-09-05 | 0 | Details |
| US2519426A | Alternating current control device | Expired / Lapsed | 1948-02-26 | 1950-08-22 | 0 | Details |
| US2519688A | Signal code translator | Expired / Lapsed | 1946-11-08 | 1950-08-22 | 0 | Details |
| US2518022A | Translator | Expired / Lapsed | 1948-09-30 | 1950-08-08 | 0 | Details |
| US2518331A | Piezoelectric crystal mounting | Expired / Lapsed | 1948-05-06 | 1950-08-08 | 0 | Details |
| US2516587A | Correction of errors in pulse code communication | Expired / Lapsed | 1947-12-03 | 1950-07-25 | 0 | Details |
| US2516765A | Tracking control | Expired / Lapsed | 1944-02-24 | 1950-07-25 | 0 | Details |
| US2516069A | Observer-controlled television system | Expired / Lapsed | 1947-07-29 | 1950-07-18 | 0 | Details |
| US2515332A | Object locating system | Expired / Lapsed | 1943-08-12 | 1950-07-18 | 0 | Details |
| US2515054A | Light modulating system | Expired / Lapsed | 1948-08-11 | 1950-07-11 | 0 | Details |
| US2514671A | Decoder for pulse code modulation | Expired / Lapsed | 1947-09-23 | 1950-07-11 | 0 | Details |
| US2514678A | Wave guide system | Expired / Lapsed | 1942-06-30 | 1950-07-11 | 0 | Details |
| US2514080A | Method of obtaining high velocity with crystals | Expired / Lapsed | 1945-01-10 | 1950-07-04 | 0 | Details |
| US2511195A | Recording pen check mechanism | Expired / Lapsed | 1948-04-30 | 1950-06-13 | 0 | Details |
| US2511121A | Method of recording information on stationary magnetic mate… | Expired / Lapsed | 1948-02-14 | 1950-06-13 | 0 | Details |
| US2510061A | Code translator and printer control circuit | Expired / Lapsed | 1949-01-21 | 1950-06-06 | 0 | Details |
| US2509889A | Differential altimeter | Expired / Lapsed | 1948-01-13 | 1950-05-30 | 0 | Details |
| US2509909A | Conductive device | Expired / Lapsed | 1946-12-31 | 1950-05-30 | 0 | Details |
| US2508547A | Calibration system | Expired / Lapsed | 1948-07-27 | 1950-05-23 | 0 | Details |
| US2509068A | Polarimetric method and means of determining the degree of … | Expired / Lapsed | 1948-02-20 | 1950-05-23 | 0 | Details |
| US2508511A | Resistor coated with ceramic composition | Expired / Lapsed | 1946-12-12 | 1950-05-23 | 2 | Details |
| US2508622A | Pulse code modulation communication system | Expired / Lapsed | 1945-07-09 | 1950-05-23 | 0 | Details |
| US2508509A | Apparatus for coating hollow objects | Expired / Lapsed | 1945-01-13 | 1950-05-23 | 0 | Details |
| US2507566A | Electrical testing apparatus | Expired / Lapsed | 1948-08-30 | 1950-05-16 | 0 | Details |
| US2506429A | Selective signaling system | Expired / Lapsed | 1946-05-31 | 1950-05-02 | 0 | Details |
| US2506130A | Metalized ceramic coating composition | Expired / Lapsed | 1945-08-14 | 1950-05-02 | 2 | Details |
| US2505029A | Decoder for pulse code modulation | Expired / Lapsed | 1949-02-09 | 1950-04-25 | 0 | Details |
| US2505040A | Regenerative relay repeater | Expired / Lapsed | 1948-06-04 | 1950-04-25 | 0 | Details |
| US2505370A | Piezoelectric crystal unit | Expired / Lapsed | 1947-11-08 | 1950-04-25 | 0 | Details |
| US2505566A | Signaling system | Expired / Lapsed | 1945-07-23 | 1950-04-25 | 0 | Details |
| US2504621A | Enciphering and deciphering device for secret telegraph sys… | Expired / Lapsed | 1946-12-03 | 1950-04-18 | 0 | Details |
| US2503831A | Fine wire delay line | Expired / Lapsed | 1949-01-07 | 1950-04-11 | 0 | Details |
| US2503391A | Automatic volume control | Expired / Lapsed | 1949-01-06 | 1950-04-11 | 0 | Details |
| US2503846A | Telephone set | Expired / Lapsed | 1946-12-27 | 1950-04-11 | 0 | Details |
| US2503837A | Electrical translating device | Expired / Lapsed | 1945-07-27 | 1950-04-11 | 0 | Details |
| US2503429A | Metallic casing for electrical units | Expired / Lapsed | 1944-09-26 | 1950-04-11 | 0 | Details |
| US2502488A | Semiconductor amplifier | Expired / Lapsed | 1948-09-24 | 1950-04-04 | 0 | Details |
| US2502837A | Position indicating system | Expired / Lapsed | 1943-11-24 | 1950-04-04 | 0 | Details |
| US2500638A | Aid for the blind | Expired / Lapsed | 1946-04-26 | 1950-03-14 | 0 | Details |
| US2499759A | Location of faults in electrical transmission systems | Expired / Lapsed | 1947-07-31 | 1950-03-07 | 0 | Details |
| US2497770A | Transistor-microphone | Expired / Lapsed | 1948-12-29 | 1950-02-14 | 0 | Details |
| US2496633A | Multitarget cathode-ray device | Expired / Lapsed | 1947-12-24 | 1950-02-07 | 0 | Details |
| US2494483A | Centrifugal force compensating mechanism | Expired / Lapsed | 1947-11-12 | 1950-01-10 | 0 | Details |
| US2494323A | Signal receiving apparatus | Expired / Lapsed | 1943-03-12 | 1950-01-10 | 0 | Details |
| US2493183A | Artillery director | Expired / Lapsed | 1942-05-21 | 1950-01-03 | 0 | Details |
| US2492351A | Smoothing network | Expired / Lapsed | 1944-02-23 | 1949-12-27 | 0 | Details |
| US2491662A | Attenuator | Expired / Lapsed | 1945-03-30 | 1949-12-20 | 0 | Details |
| US2489883A | Pulse code modulation receiver employing cathode-ray tube d… | Expired / Lapsed | 1946-12-28 | 1949-11-29 | 0 | Details |
| US2489865A | Directional microwave antenna | Expired / Lapsed | 1944-07-31 | 1949-11-29 | 0 | Details |
| US2488580A | Temperature control system | Expired / Lapsed | 1946-03-07 | 1949-11-22 | 0 | Details |
| US2488341A | Detection system | Expired / Lapsed | 1945-09-25 | 1949-11-15 | 0 | Details |
| US2488448A | Computing circuit for determining bomb release points | Expired / Lapsed | 1945-04-27 | 1949-11-15 | 0 | Details |
| US2486776A | Self-biased electric translating device | Expired / Lapsed | 1948-04-21 | 1949-11-01 | 0 | Details |
| US2486491A | Gate distributor circuits | Expired / Lapsed | 1946-02-08 | 1949-11-01 | 0 | Details |
| US2486187A | Piezoelectric crystal apparatus | Expired / Lapsed | 1947-04-09 | 1949-10-25 | 0 | Details |
| US2485069A | Translating material of silicon base | Expired / Lapsed | 1944-07-20 | 1949-10-18 | 0 | Details |
| US2484226A | Indicating circuit | Expired / Lapsed | 1947-10-17 | 1949-10-11 | 0 | Details |
| US2484626A | Electromechanical transducer | Expired / Lapsed | 1946-07-26 | 1949-10-11 | 0 | Details |
| US2484612A | Directory number calling line identifier | Expired / Lapsed | 1946-05-17 | 1949-10-11 | 0 | Details |
| US2484623A | Thickness measurement | Expired / Lapsed | 1944-10-17 | 1949-10-11 | 0 | Details |
| US2484618A | Wave receiving system | Expired / Lapsed | 1944-08-26 | 1949-10-11 | 0 | Details |
| US2482178A | Composite structure for forming a seal with glass | Expired / Lapsed | 1944-02-29 | 1949-09-20 | 0 | Details |
| US2482162A | Directive microwave antenna | Expired / Lapsed | 1943-06-05 | 1949-09-20 | 0 | Details |
| US2481932A | Supervisory signaling in telephone systems | Expired / Lapsed | 1946-12-27 | 1949-09-13 | 0 | Details |
| US2481112A | Teletypewriter permutation code signal combination counter | Expired / Lapsed | 1946-09-13 | 1949-09-06 | 0 | Details |
| US2480038A | Compensation of distortion in guided waves | Expired / Lapsed | 1946-06-08 | 1949-08-23 | 0 | Details |
| US2479909A | Computing circuit for determining bomb release course | Expired / Lapsed | 1945-04-27 | 1949-08-23 | 0 | Details |
| US2479924A | Method of making electrical conductor cables | Expired / Lapsed | 1944-04-25 | 1949-08-23 | 0 | Details |
| US2478414A | Breakdown testing apparatus | Expired / Lapsed | 1944-01-07 | 1949-08-09 | 0 | Details |
| US2477047A | Frequency divider circuit | Expired / Lapsed | 1946-09-21 | 1949-07-26 | 0 | Details |
| US2477076A | Frequency control system | Expired / Lapsed | 1945-10-12 | 1949-07-26 | 0 | Details |
| US2477246A | Submarine signaling device | Expired / Lapsed | 1945-05-16 | 1949-07-26 | 0 | Details |
| US2477232A | Cavity resonator | Expired / Lapsed | 1945-03-28 | 1949-07-26 | 0 | Details |
| US2477337A | Magnetic detector | Expired / Lapsed | 1944-07-31 | 1949-07-26 | 0 | Details |
| US2476323A | Multielectrode modulator | Expired / Lapsed | 1948-05-19 | 1949-07-19 | 0 | Details |
| US2476844A | Motor control circuit | Expired / Lapsed | 1946-04-03 | 1949-07-19 | 0 | Details |
| US2476747A | Electrical computing system | Expired / Lapsed | 1942-04-25 | 1949-07-19 | 0 | Details |
| US2476034A | Conformal grating resonant cavity | Expired / Lapsed | 1945-07-16 | 1949-07-12 | 0 | Details |
| US2476032A | Doppler effect speed and drift indicating system | Expired / Lapsed | 1944-03-08 | 1949-07-12 | 0 | Details |
| US2475188A | Sweep amplifier | Expired / Lapsed | 1944-12-20 | 1949-07-05 | 0 | Details |
| US2475434A | Apparatus for masking articles | Expired / Lapsed | 1944-06-20 | 1949-07-05 | 0 | Details |
| US2474898A | Electromagnetic resonator of the magnetron type | Expired / Lapsed | 1944-04-05 | 1949-07-05 | 0 | Details |
| US2472753A | Piezoelectric crystal apparatus | Expired / Lapsed | 1946-08-16 | 1949-06-07 | 0 | Details |
| US2471262A | Means for multiplying voltages | Expired / Lapsed | 1946-10-24 | 1949-05-24 | 0 | Details |
| US2470825A | Electrical contact protection network | Expired / Lapsed | 1945-04-10 | 1949-05-24 | 0 | Details |
| US2471315A | Aircraft trainer for aerial gunners | Expired / Lapsed | 1944-02-03 | 1949-05-24 | 0 | Details |
| US2470145A | Multifrequency signaling system | Expired / Lapsed | 1947-09-25 | 1949-05-17 | 0 | Details |
| US2469837A | Wave translating system | Expired / Lapsed | 1946-09-26 | 1949-05-10 | 0 | Details |
| US2469569A | Point contact negative resistance devices | Expired / Lapsed | 1945-03-02 | 1949-05-10 | 0 | Details |
| US2468462A | Telegraph transmitter control mechanism | Expired / Lapsed | 1945-07-04 | 1949-04-26 | 0 | Details |
| US2467299A | High-frequency transmission system | Expired / Lapsed | 1942-11-12 | 1949-04-12 | 0 | Details |
| US2465540A | Electrical connector | Expired / Lapsed | 1946-03-26 | 1949-03-29 | 0 | Details |
| US2464594A | Phase and amplitude control circuit for wide band amplifiers | Expired / Lapsed | 1946-04-06 | 1949-03-15 | 0 | Details |
| US2464607A | Pulse code modulation communication system | Expired / Lapsed | 1945-07-09 | 1949-03-15 | 0 | Details |
| US2463535A | Electron discharge device | Expired / Lapsed | 1946-12-13 | 1949-03-08 | 0 | Details |
| US2461878A | Metallizing composition | Expired / Lapsed | 1944-11-01 | 1949-02-15 | 0 | Details |
| US2460688A | Apparatus for locating faults in cables | Expired / Lapsed | 1944-05-04 | 1949-02-01 | 0 | Details |
| US2460401A | Directive microwave radio antenna | Expired / Lapsed | 1943-04-01 | 1949-02-01 | 0 | Details |
| US2460090A | Frequency selective apparatus | Expired / Lapsed | 1945-11-26 | 1949-01-25 | 0 | Details |
| US2460064A | Motor control circuit | Expired / Lapsed | 1945-05-16 | 1949-01-25 | 0 | Details |
| US2459306A | Contact protection for mercury wetted switch contacts | Expired / Lapsed | 1944-07-21 | 1949-01-18 | 0 | Details |
| US2458552A | Method of making electrical contacting elements | Expired / Lapsed | 1946-11-09 | 1949-01-11 | 0 | Details |
| US2458654A | System for and method of utilizing microwave radiation from… | Expired / Lapsed | 1943-12-27 | 1949-01-11 | 0 | Details |
| US2458556A | Coupled cavity resonator and wave guide apparatus | Expired / Lapsed | 1942-03-05 | 1949-01-11 | 0 | Details |
| US2458030A | Selective signaling apparatus and system | Expired / Lapsed | 1944-08-29 | 1949-01-04 | 0 | Details |
| US2458175A | Directive antenna control system | Expired / Lapsed | 1944-07-27 | 1949-01-04 | 0 | Details |
| US2457524A | Wave guide repeater | Expired / Lapsed | 1945-05-26 | 1948-12-28 | 0 | Details |
| US2457218A | Method of manufacturing sealed contact devices | Expired / Lapsed | 1944-12-14 | 1948-12-28 | 0 | Details |
| US2455387A | Thermostat-controlled heater circuit | Expired / Lapsed | 1946-10-02 | 1948-12-07 | 0 | Details |
| US2455472A | Method and system for electronically generating complex sig… | Expired / Lapsed | 1945-04-10 | 1948-12-07 | 0 | Details |
| US2455520A | Temperature controlled test system | Expired / Lapsed | 1944-03-24 | 1948-12-07 | 0 | Details |
| US2455035A | Averaging mechanism | Expired / Lapsed | 1946-01-30 | 1948-11-30 | 0 | Details |
| US2454329A | Take-up mechanism | Expired / Lapsed | 1947-11-28 | 1948-11-23 | 0 | Details |
| US2454045A | Amplifier | Expired / Lapsed | 1945-05-16 | 1948-11-16 | 0 | Details |
| US2454089A | Regenerative repeater | Expired / Lapsed | 1942-10-06 | 1948-11-16 | 0 | Details |
| US2453454A | Coder for code modulation transmission | Expired / Lapsed | 1946-08-31 | 1948-11-09 | 0 | Details |
| US2453461A | Code modulation communication system | Expired / Lapsed | 1946-06-19 | 1948-11-09 | 0 | Details |
| US2453243A | Frequency modulating and harmonic producer apparatus | Expired / Lapsed | 1943-10-21 | 1948-11-09 | 0 | Details |
| US2452655A | Cathode-ray oscilloscope circuit | Expired / Lapsed | 1947-04-25 | 1948-11-02 | 0 | Details |
| US2452052A | Selectively responsive device | Expired / Lapsed | 1946-12-30 | 1948-10-26 | 0 | Details |
| US2452051A | Relay system | Expired / Lapsed | 1945-03-15 | 1948-10-26 | 0 | Details |
| US2451465A | Transversal filter | Expired / Lapsed | 1947-02-27 | 1948-10-19 | 0 | Details |
| US2451572A | Radiant energy measuring apparatus | Expired / Lapsed | 1945-12-27 | 1948-10-19 | 0 | Details |
| US2451632A | Control voltage means in pulse receiver | Expired / Lapsed | 1944-02-24 | 1948-10-19 | 0 | Details |
| US2451484A | Cathode-ray signal utilizing means | Expired / Lapsed | 1943-10-05 | 1948-10-19 | 0 | Details |
| US2451044A | Communication system employing pulse code modulation | Expired / Lapsed | 1945-07-09 | 1948-10-12 | 0 | Details |
| US2450516A | Telemetric data transmission system | Expired / Lapsed | 1944-01-11 | 1948-10-05 | 0 | Details |
| US2449848A | Pulse-actuated circuit | Expired / Lapsed | 1943-08-12 | 1948-09-21 | 0 | Details |
| US2448581A | Testing circuits for piezoelectric crystals | Expired / Lapsed | 1945-01-27 | 1948-09-07 | 0 | Details |
| US2446672A | Method of machining article blanks | Expired / Lapsed | 1944-07-26 | 1948-08-10 | 0 | Details |
| US2446674A | Cathode-ray device mounting | Expired / Lapsed | 1944-02-18 | 1948-08-10 | 0 | Details |
| US2445896A | Dielectric wave guide coupling arrangement for use in two-w… | Expired / Lapsed | 1945-03-06 | 1948-07-27 | 0 | Details |
| US2444435A | Frequency control of magnetron oscillators | Expired / Lapsed | 1942-05-01 | 1948-07-06 | 0 | Details |
| US2444349A | Cyrstal oscillator circuits | Expired / Lapsed | 1945-10-31 | 1948-06-29 | 0 | Details |
| US2444338A | Oscilloscope circuit | Expired / Lapsed | 1945-06-04 | 1948-06-29 | 0 | Details |
| US2444069A | System for receiving sounds in the presence of disturbing n… | Expired / Lapsed | 1945-03-02 | 1948-06-29 | 0 | Details |
| US2444078A | Trouble alarm system | Expired / Lapsed | 1942-06-10 | 1948-06-29 | 0 | Details |
| US2443643A | Wave modifying device | Expired / Lapsed | 1945-09-07 | 1948-06-22 | 0 | Details |
| US2443619A | Pulse generator of the shockexcited type | Expired / Lapsed | 1945-02-08 | 1948-06-22 | 0 | Details |
| US2443623A | Data transmitting and indicating system | Expired / Lapsed | 1942-07-22 | 1948-06-22 | 0 | Details |
| US2443624A | Range computer | Expired / Lapsed | 1942-04-23 | 1948-06-22 | 0 | Details |
| US2443534A | Space discharge voltage regulation circuit | Expired / Lapsed | 1945-06-15 | 1948-06-15 | 0 | Details |
| US2442766A | Circuit controlling switch | Expired / Lapsed | 1945-03-08 | 1948-06-08 | 0 | Details |
| US2442702A | Selective signaling system | Expired / Lapsed | 1945-09-20 | 1948-06-01 | 0 | Details |
| US2442351A | Training device for object locating signaling systems | Expired / Lapsed | 1943-12-06 | 1948-06-01 | 0 | Details |
| US2442330A | Methods of vulcanizing saturated linear polymers and vulcan… | Expired / Lapsed | 1943-04-30 | 1948-06-01 | 0 | Details |
| US2441557A | Selective signaling system | Expired / Lapsed | 1945-02-08 | 1948-05-18 | 0 | Details |
| US2441598A | Wave transmission | Expired / Lapsed | 1944-06-16 | 1948-05-18 | 0 | Details |
| US2441603A | Electrical translating materials and method of making them | Expired / Lapsed | 1943-07-28 | 1948-05-18 | 0 | Details |
| US2441139A | Piezoelectric crystal mounting | Expired / Lapsed | 1946-04-29 | 1948-05-11 | 0 | Details |
| US2440480A | Electrical insulation testing apparatus | Expired / Lapsed | 1944-03-31 | 1948-04-27 | 0 | Details |
| US2439381A | Computing bomb sight | Expired / Lapsed | 1943-07-17 | 1948-04-13 | 0 | Details |
| US2438893A | Translating device | Expired / Lapsed | 1943-12-29 | 1948-04-06 | 0 | Details |
| US2438940A | Range and azimuth simulating system for radar instruction | Expired / Lapsed | 1943-12-06 | 1948-04-06 | 0 | Details |
| US2438888A | Radio object detector training device | Expired / Lapsed | 1943-12-06 | 1948-04-06 | 0 | Details |
| US2438892A | Electrical translating materials and devices and methods of… | Expired / Lapsed | 1943-07-28 | 1948-04-06 | 0 | Details |
| US2438947A | Electronic modulation and modulation correction circuits | Expired / Lapsed | 1943-07-28 | 1948-04-06 | 0 | Details |
| US2438492A | Signaling system | Expired / Lapsed | 1944-08-17 | 1948-03-30 | 0 | Details |
| US2438110A | Electrical translating materials and devices and method of … | Expired / Lapsed | 1943-07-28 | 1948-03-23 | 0 | Details |
| US2437707A | Communication system employing pulse code modulation | Expired / Lapsed | 1945-12-27 | 1948-03-16 | 0 | Details |
| US2437270A | Magnetostrictive compressional wave transmitter or receiver | Expired / Lapsed | 1943-11-05 | 1948-03-09 | 0 | Details |
| US2436809A | Electric combination lock | Expired / Lapsed | 1945-05-19 | 1948-03-02 | 0 | Details |
| US2436393A | Cathode-ray tube with discharge to deflecting plates | Expired / Lapsed | 1944-12-29 | 1948-02-24 | 0 | Details |
| US2435598A | Electric pulse delay circuit | Expired / Lapsed | 1943-12-28 | 1948-02-10 | 0 | Details |
| US2435585A | High-frequency relay employing an electron discharge device | Expired / Lapsed | 1941-12-20 | 1948-02-10 | 0 | Details |
| US2435207A | Phase synchronized pulsed trigger circuit | Expired / Lapsed | 1945-09-28 | 1948-02-03 | 0 | Details |
| US2434898A | Digit registering means responsive to selective frequencies | Expired / Lapsed | 1946-01-16 | 1948-01-27 | 0 | Details |
| US2434946A | Tone supply test circuit | Expired / Lapsed | 1944-03-16 | 1948-01-27 | 0 | Details |
| US2434681A | Remotely controlled electrical calculator | Expired / Lapsed | 1943-02-13 | 1948-01-20 | 0 | Details |
| US2434336A | Continuity and short-circuit test set | Expired / Lapsed | 1946-05-15 | 1948-01-13 | 0 | Details |
| US2434264A | Cathode-ray oscilloscope circuit with timing marks | Expired / Lapsed | 1944-10-17 | 1948-01-13 | 0 | Details |
| US2434274A | Artillery computer | Expired / Lapsed | 1944-04-11 | 1948-01-13 | 0 | Details |
| US2434259A | Circuit arrangement utilizing a plurality of electron disch… | Expired / Lapsed | 1943-06-22 | 1948-01-13 | 0 | Details |
| US2434273A | Wave translating system | Expired / Lapsed | 1943-01-21 | 1948-01-13 | 0 | Details |
| US2433836A | Telephone call transmitter | Expired / Lapsed | 1945-04-04 | 1948-01-06 | 0 | Details |
| US2433340A | Phase correcting arrangement for electronic type selecting … | Expired / Lapsed | 1945-07-06 | 1947-12-30 | 0 | Details |
| US2433382A | Recorder system with electromagnetically attracted electric… | Expired / Lapsed | 1944-09-11 | 1947-12-30 | 0 | Details |
| US2433385A | Submarine locating system | Expired / Lapsed | 1942-11-05 | 1947-12-30 | 0 | Details |
| US2433383A | Crystal microphone | Expired / Lapsed | 1942-06-24 | 1947-12-30 | 0 | Details |
| US2433002A | Pulse-type position indicator | Expired / Lapsed | 1944-09-29 | 1947-12-23 | 0 | Details |
| US2432516A | Keyed pulse generator | Expired / Lapsed | 1943-12-30 | 1947-12-16 | 0 | Details |
| US2432504A | Target azimuth device | Expired / Lapsed | 1943-09-17 | 1947-12-16 | 0 | Details |
| US2432944A | Oscillograph system for testing electrical contact making d… | Expired / Lapsed | 1943-08-28 | 1947-12-16 | 0 | Details |
| US2432454A | Manual range gate for stroboscopic indicators | Expired / Lapsed | 1945-11-08 | 1947-12-09 | 0 | Details |
| US2432123A | Translation of visual symbols | Expired / Lapsed | 1945-04-05 | 1947-12-09 | 0 | Details |
| US2432134A | Directional radio system | Expired / Lapsed | 1944-06-28 | 1947-12-09 | 0 | Details |
| US2432116A | Crystal detector mounting | Expired / Lapsed | 1943-04-19 | 1947-12-09 | 0 | Details |
| US2432093A | Wave transmission network | Expired / Lapsed | 1942-07-30 | 1947-12-09 | 0 | Details |
| US2431692A | Alternate route telephone switching mechanism | Expired / Lapsed | 1945-05-15 | 1947-12-02 | 0 | Details |
| US2431696A | Relay desing calculator | Expired / Lapsed | 1944-08-23 | 1947-12-02 | 0 | Details |
| US2430447A | Printing telegraph automatic switching system | Expired / Lapsed | 1942-06-27 | 1947-11-11 | 0 | Details |
| US2430038A | Cathode-ray device for improving signal-to-noise ratio in r… | Expired / Lapsed | 1943-10-05 | 1947-11-04 | 0 | Details |
| US2430028A | Translating device and method of making it | Expired / Lapsed | 1943-03-16 | 1947-11-04 | 0 | Details |
| US2429933A | Image translating device | Expired / Lapsed | 1945-08-08 | 1947-10-28 | 0 | Details |
| US2429651A | Control system for two-phase induction motors | Expired / Lapsed | 1945-01-01 | 1947-10-28 | 0 | Details |
| US2429601A | Microwave radar directive antenna | Expired / Lapsed | 1943-11-22 | 1947-10-28 | 0 | Details |
| US2429236A | Analysis and representation of complex waves | Expired / Lapsed | 1945-04-05 | 1947-10-21 | 0 | Details |
| US2429229A | Analysis and representation of complex waves | Expired / Lapsed | 1945-04-04 | 1947-10-21 | 0 | Details |
| US2429216A | Electrical phase indicating apparatus | Expired / Lapsed | 1944-10-04 | 1947-10-21 | 0 | Details |
| US2429222A | Method of making contact wires | Expired / Lapsed | 1943-06-05 | 1947-10-21 | 0 | Details |
| US2428800A | Telemetric summation system | Expired / Lapsed | 1944-06-30 | 1947-10-14 | 0 | Details |
| US2428767A | Electric motor control circuits | Expired / Lapsed | 1943-09-15 | 1947-10-14 | 0 | Details |
| US2428366A | Pulse multiplex system | Expired / Lapsed | 1945-02-08 | 1947-10-07 | 0 | Details |
| US2428007A | Telephone call-indicating facilities | Expired / Lapsed | 1944-12-01 | 1947-09-30 | 0 | Details |
| US2428058A | Object locating and distance measuring systems of the pulse… | Expired / Lapsed | 1943-10-27 | 1947-09-30 | 0 | Details |
| US2427666A | Magnetic field strength indicator | Expired / Lapsed | 1943-04-20 | 1947-09-23 | 0 | Details |
| US2427417A | Method of manufacturing electrical resistors | Expired / Lapsed | 1945-07-14 | 1947-09-16 | 0 | Details |
| US2427348A | Piezoelectric vibrator | Expired / Lapsed | 1941-08-19 | 1947-09-16 | 0 | Details |
| US2426996A | Frequency modulation | Expired / Lapsed | 1944-08-17 | 1947-09-09 | 0 | Details |
| US2427005A | Directive microwave antenna | Expired / Lapsed | 1943-11-06 | 1947-09-09 | 0 | Details |
| US2427198A | Conductor insulated with rubber compound layers bonded toge… | Expired / Lapsed | 1942-08-18 | 1947-09-09 | 0 | Details |
| US2427197A | Bonding of rubber and rubberlike compositions | Expired / Lapsed | 1942-08-18 | 1947-09-09 | 0 | Details |
| US2426622A | Magnetic field detector | Expired / Lapsed | 1944-09-21 | 1947-09-02 | 0 | Details |
| US2426650A | Method of soldering a terminal to a piezoelectric crystal | Expired / Lapsed | 1943-12-27 | 1947-09-02 | 0 | Details |
| US2426232A | Distance measuring system | Expired / Lapsed | 1944-02-05 | 1947-08-26 | 0 | Details |
| US2426182A | Time division radar ranging system | Expired / Lapsed | 1943-10-01 | 1947-08-26 | 0 | Details |
| US2426216A | Aperiodic pulse timing system | Expired / Lapsed | 1942-10-19 | 1947-08-26 | 0 | Details |
| US2426189A | Object locating system | Expired / Lapsed | 1941-10-04 | 1947-08-26 | 0 | Details |
| US2425346A | Automatic dead reckoning device | Expired / Lapsed | 1944-10-02 | 1947-08-12 | 0 | Details |
| US2425345A | Microwave transmission system | Expired / Lapsed | 1942-12-23 | 1947-08-12 | 0 | Details |
| US2425003A | Analysis and representation of complex waves | Expired / Lapsed | 1944-12-23 | 1947-08-05 | 0 | Details |
| US2424971A | Frequency-shift radio telegraph transmitting system | Expired / Lapsed | 1944-07-21 | 1947-08-05 | 0 | Details |
| US2425002A | Electrical apparatus | Expired / Lapsed | 1944-07-08 | 1947-08-05 | 0 | Details |
| US2424571A | Telegraph alarm system | Expired / Lapsed | 1943-09-01 | 1947-07-29 | 0 | Details |
| US2424246A | Frequency-modulated crystal oscillator | Expired / Lapsed | 1943-09-16 | 1947-07-22 | 0 | Details |
| US2423466A | Time division multiplex | Expired / Lapsed | 1944-08-01 | 1947-07-08 | 0 | Details |
| US2423437A | Direction finder | Expired / Lapsed | 1934-08-25 | 1947-07-08 | 0 | Details |
| US2423125A | Photoelectromotive force cell of the silicon-silicon oxide … | Expired / Lapsed | 1944-05-16 | 1947-07-01 | 0 | Details |
| US2423130A | Switching device in wave guide transmission system | Expired / Lapsed | 1944-03-25 | 1947-07-01 | 0 | Details |
| US2422697A | Viewing system | Expired / Lapsed | 1944-11-15 | 1947-06-24 | 0 | Details |
| US2422664A | Wobbled radio carrier communication system | Expired / Lapsed | 1944-07-12 | 1947-06-24 | 0 | Details |
| US2422655A | Time measuring system | Expired / Lapsed | 1943-09-16 | 1947-06-24 | 0 | Details |
| US2422654A | Time measuring system | Expired / Lapsed | 1943-08-19 | 1947-06-24 | 0 | Details |
| US2422698A | Time measuring system | Expired / Lapsed | 1942-11-05 | 1947-06-24 | 0 | Details |
| US2422191A | Impedance transformer for wave guides | Expired / Lapsed | 1945-08-25 | 1947-06-17 | 0 | Details |
| US2422205A | Range indicator | Expired / Lapsed | 1943-10-05 | 1947-06-17 | 0 | Details |
| US2422212A | Adjustable step-by-step motor | Expired / Lapsed | 1943-10-02 | 1947-06-17 | 0 | Details |
| US2422204A | Range indicator | Expired / Lapsed | 1943-06-22 | 1947-06-17 | 0 | Details |
| US2421919A | Telephone routing system | Expired / Lapsed | 1944-04-29 | 1947-06-10 | 0 | Details |
| US2421973A | Article assembling fixture | Expired / Lapsed | 1943-10-19 | 1947-06-10 | 0 | Details |
| US2421747A | Object locating system | Expired / Lapsed | 1943-07-14 | 1947-06-10 | 0 | Details |
| US2420342A | High frequency continuous amplifier | Expired / Lapsed | 1943-03-18 | 1947-05-13 | 0 | Details |
| US2419583A | Testing and indicating system | Expired / Lapsed | 1945-01-20 | 1947-04-29 | 0 | Details |
| US2419537A | Resistor | Expired / Lapsed | 1944-09-09 | 1947-04-29 | 0 | Details |
| US2419201A | Pulse generator | Expired / Lapsed | 1943-11-30 | 1947-04-22 | 0 | Details |
| US2418809A | Wave transmission system | Expired / Lapsed | 1943-08-25 | 1947-04-15 | 0 | Details |
| US2418932A | Method of making enamel coated articles | Expired / Lapsed | 1940-11-13 | 1947-04-15 | 0 | Details |
| US2418460A | Resistor | Expired / Lapsed | 1943-12-31 | 1947-04-08 | 0 | Details |
| US2418136A | Acoustic range finder | Expired / Lapsed | 1943-11-10 | 1947-04-01 | 0 | Details |
| US2417831A | Counting relay system | Expired / Lapsed | 1943-09-03 | 1947-03-25 | 0 | Details |
| US2417829A | Compressional wave signaling device | Expired / Lapsed | 1942-12-31 | 1947-03-25 | 0 | Details |
| US2417420A | Terminal block | Expired / Lapsed | 1944-11-29 | 1947-03-18 | 0 | Details |
| US2417446A | Stereotelevision and television range finding | Expired / Lapsed | 1941-08-01 | 1947-03-18 | 0 | Details |
| US2416320A | Cathode-ray tube circuit | Expired / Lapsed | 1944-02-24 | 1947-02-25 | 0 | Details |
| US2416298A | Magnetron and control | Expired / Lapsed | 1942-11-02 | 1947-02-25 | 0 | Details |
| US2416290A | Cathode-ray oscilloscope circuit | Expired / Lapsed | 1942-10-02 | 1947-02-25 | 0 | Details |
| US2416351A | Position locating system | Expired / Lapsed | 1942-04-03 | 1947-02-25 | 0 | Details |
| US2415841A | Conducting material and device and method of making them | Expired / Lapsed | 1944-12-14 | 1947-02-18 | 0 | Details |
| US2415832A | Radiation absorber | Expired / Lapsed | 1942-12-31 | 1947-02-18 | 0 | Details |
| US2415405A | Stabilizing circuit for synchronous motors | Expired / Lapsed | 1944-04-12 | 1947-02-11 | 0 | Details |
| US2415089A | Microwave antennas | Expired / Lapsed | 1942-05-28 | 1947-02-04 | 0 | Details |
| US2414792A | Bolometric thermistor | Expired / Lapsed | 1945-06-29 | 1947-01-28 | 0 | Details |
| US2414819A | Computer for ballistic interactions | Expired / Lapsed | 1944-12-29 | 1947-01-28 | 0 | Details |
| US2414486A | Sweep control circuits | Expired / Lapsed | 1943-11-30 | 1947-01-21 | 0 | Details |
| US2414477A | Indicating apparatus | Expired / Lapsed | 1943-10-05 | 1947-01-21 | 0 | Details |
| US2414479A | Impulse generator | Expired / Lapsed | 1942-11-05 | 1947-01-21 | 0 | Details |
| US2414085A | Oscillator | Expired / Lapsed | 1944-12-14 | 1947-01-14 | 0 | Details |
| US2414096A | Scanning system | Expired / Lapsed | 1944-02-04 | 1947-01-14 | 0 | Details |
| US2414084A | Tunable resonator and oscillator | Expired / Lapsed | 1943-05-11 | 1947-01-14 | 0 | Details |
| US2414121A | Electron device of the magnetron type | Expired / Lapsed | 1941-01-17 | 1947-01-14 | 0 | Details |
| US2413715A | Retractile cord | Expired / Lapsed | 1943-10-15 | 1947-01-07 | 0 | Details |
| US2413033A | Voltage regulated rectifying system | Expired / Lapsed | 1942-07-29 | 1946-12-24 | 0 | Details |
| US2412642A | Electronic telegraph transmitter distributor | Expired / Lapsed | 1943-08-25 | 1946-12-17 | 0 | Details |
| US2412210A | Cathode-ray sweep circuit | Expired / Lapsed | 1942-03-21 | 1946-12-10 | 0 | Details |
| US2412202A | Directive radio system | Expired / Lapsed | 1941-06-28 | 1946-12-10 | 0 | Details |
| US2411531A | Electro-optical control system | Expired / Lapsed | 1944-10-20 | 1946-11-26 | 0 | Details |
| US2411537A | Submarine signaling system | Expired / Lapsed | 1944-01-28 | 1946-11-26 | 0 | Details |
| US2410825A | Piezoelectric crystal apparatus | Expired / Lapsed | 1943-03-04 | 1946-11-12 | 0 | Details |
| US2409608A | Ultra high frequency detector | Expired / Lapsed | 1941-09-24 | 1946-10-22 | 0 | Details |
| US2409151A | Electrical regulating device | Expired / Lapsed | 1943-02-02 | 1946-10-08 | 0 | Details |
| US2408433A | Telephone system | Expired / Lapsed | 1943-02-13 | 1946-10-01 | 0 | Details |
| US2408409A | Ultra high frequency electronic device | Expired / Lapsed | 1941-04-08 | 1946-10-01 | 0 | Details |
| US2408435A | Pipe antenna and prism | Expired / Lapsed | 1941-03-01 | 1946-10-01 | 0 | Details |
| US2408093A | Method of making wire-wound cardtype resistance devices | Expired / Lapsed | 1944-01-24 | 1946-09-24 | 0 | Details |
| US2408085A | Communication system | Expired / Lapsed | 1943-07-23 | 1946-09-24 | 0 | Details |
| US2408108A | Television image production | Expired / Lapsed | 1943-05-11 | 1946-09-24 | 0 | Details |
| US2408086A | Impulse system | Expired / Lapsed | 1941-06-05 | 1946-09-24 | 0 | Details |
| US2408081A | Artillery predictor | Expired / Lapsed | 1941-05-01 | 1946-09-24 | 0 | Details |
| US2407690A | Wave guide electrotherapeutic system | Expired / Lapsed | 1941-05-16 | 1946-09-17 | 0 | Details |
| US2407298A | Electron discharge apparatus | Expired / Lapsed | 1942-12-15 | 1946-09-10 | 0 | Details |
| US2407286A | Communication system | Expired / Lapsed | 1942-11-07 | 1946-09-10 | 0 | Details |
| US2407320A | Electronic counter | Expired / Lapsed | 1942-11-05 | 1946-09-10 | 0 | Details |
| US2407325A | Range converter | Expired / Lapsed | 1942-04-23 | 1946-09-10 | 0 | Details |
| US2407260A | Privacy system | Expired / Lapsed | 1941-07-19 | 1946-09-10 | 0 | Details |
| US2407259A | Transmission control in signaling systems | Expired / Lapsed | 1941-07-09 | 1946-09-10 | 0 | Details |
| US2407274A | Ultra high frequency electronic device | Expired / Lapsed | 1941-04-16 | 1946-09-10 | 0 | Details |
| US2406787A | Telegraph system | Expired / Lapsed | 1943-04-07 | 1946-09-03 | 0 | Details |
| US2406353A | Secret signaling | Expired / Lapsed | 1943-07-17 | 1946-08-27 | 0 | Details |
| US2406384A | Data transmission system | Expired / Lapsed | 1942-11-05 | 1946-08-27 | 0 | Details |
| US2406349A | Secret signaling | Expired / Lapsed | 1942-07-10 | 1946-08-27 | 0 | Details |
| US2406402A | Frequency adjustment of resonant cavities | Expired / Lapsed | 1941-09-03 | 1946-08-27 | 0 | Details |
| US2406023A | Teletypewriter signal enciphering system | Expired / Lapsed | 1944-03-25 | 1946-08-20 | 0 | Details |
| US2405992A | Directive antenna system | Expired / Lapsed | 1944-01-19 | 1946-08-20 | 0 | Details |
| US2406032A | Telegraph signal enciphering mechanism | Expired / Lapsed | 1942-11-23 | 1946-08-20 | 0 | Details |
| US2406031A | Telegraph ciphering key tape machine | Expired / Lapsed | 1942-05-21 | 1946-08-20 | 0 | Details |
| US2406046A | Telegraph signal enciphering key tape producing device | Expired / Lapsed | 1942-05-21 | 1946-08-20 | 0 | Details |
| US2406021A | Sealed reed contact device | Expired / Lapsed | 1941-07-01 | 1946-08-20 | 0 | Details |
| US2405591A | Training device | Expired / Lapsed | 1943-12-27 | 1946-08-13 | 0 | Details |
| US2405604A | Compressional wave translating device | Expired / Lapsed | 1943-03-13 | 1946-08-13 | 0 | Details |
| US2405597A | Frequency measuring system | Expired / Lapsed | 1942-11-05 | 1946-08-13 | 0 | Details |
| US2405599A | Privacy system | Expired / Lapsed | 1941-09-24 | 1946-08-13 | 0 | Details |
| US2405225A | Submarine signal system | Expired / Lapsed | 1942-10-14 | 1946-08-06 | 0 | Details |
| US2405211A | Communication system | Expired / Lapsed | 1942-07-16 | 1946-08-06 | 0 | Details |
| US2405242A | Microwave radio transmission | Expired / Lapsed | 1941-11-28 | 1946-08-06 | 0 | Details |
| US2404387A | Electrical computing system | Expired / Lapsed | 1941-05-01 | 1946-07-23 | 0 | Details |
| US2403985A | Sound reproduction | Expired / Lapsed | 1945-04-03 | 1946-07-16 | 0 | Details |
| US2403984A | Representation of complex waves | Expired / Lapsed | 1945-04-03 | 1946-07-16 | 0 | Details |
| US2403982A | Analysis and representation of complex waves | Expired / Lapsed | 1944-12-19 | 1946-07-16 | 0 | Details |
| US2403990A | Compressional wave radiator | Expired / Lapsed | 1942-08-01 | 1946-07-16 | 0 | Details |
| US2403997A | Representation of complex waves | Expired / Lapsed | 1942-04-14 | 1946-07-16 | 0 | Details |
| US2403009A | Pulse generating system and its use in signal transmission … | Expired / Lapsed | 1943-07-31 | 1946-07-02 | 0 | Details |
| US2403023A | Television follower apparatus | Expired / Lapsed | 1941-08-28 | 1946-07-02 | 0 | Details |
| US2402663A | Thermoelectric device | Expired / Lapsed | 1942-04-11 | 1946-06-25 | 0 | Details |
| US2402662A | Light-sensitive electric device | Expired / Lapsed | 1941-05-27 | 1946-06-25 | 0 | Details |
| US2402661A | Alternating current rectifier | Expired / Lapsed | 1941-03-01 | 1946-06-25 | 0 | Details |
| US2402700A | Telephone system | Expired / Lapsed | 1940-05-22 | 1946-06-25 | 0 | Details |
| US2401779A | Summing amplifier | Expired / Lapsed | 1941-05-01 | 1946-06-11 | 0 | Details |
| US2400893A | Process of carbiding | Expired / Lapsed | 1944-04-24 | 1946-05-28 | 0 | Details |
| US2400574A | Start-stop receiving selector mechanism | Expired / Lapsed | 1943-12-11 | 1946-05-21 | 0 | Details |
| US2399754A | Cathode-ray apparatus | Expired / Lapsed | 1943-01-09 | 1946-05-07 | 0 | Details |
| US2397830A | Harmonic control system | Expired / Lapsed | 1943-07-01 | 1946-04-02 | 0 | Details |
| US2396990A | Automatic line testing and switching circuits | Expired / Lapsed | 1943-12-09 | 1946-03-19 | 0 | Details |
| US2396211A | Selective calling signal device | Expired / Lapsed | 1942-09-16 | 1946-03-05 | 0 | Details |
| US2396044A | Switching device | Expired / Lapsed | 1941-12-10 | 1946-03-05 | 0 | Details |
| US2396187A | Electric recorder | Expired / Lapsed | 1939-09-29 | 1946-03-05 | 0 | Details |
| US2395477A | Motor-control circuit | Expired / Lapsed | 1944-06-30 | 1946-02-26 | 0 | Details |
| US2395539A | Telephone call transmitter | Expired / Lapsed | 1943-12-31 | 1946-02-26 | 0 | Details |
| US2395517A | Speed control system for electric motors | Expired / Lapsed | 1942-11-21 | 1946-02-26 | 0 | Details |
| US2395515A | Frequency detecting network | Expired / Lapsed | 1942-11-21 | 1946-02-26 | 0 | Details |
| US2395575A | System for the transmission of motion | Expired / Lapsed | 1942-11-02 | 1946-02-26 | 0 | Details |
| US2395560A | Wave guide | Expired / Lapsed | 1940-10-19 | 1946-02-26 | 0 | Details |
| US2395299A | Electron discharge apparatus | Expired / Lapsed | 1944-06-29 | 1946-02-19 | 0 | Details |
| US2395259A | Method of making dry rectifiers | Expired / Lapsed | 1942-10-24 | 1946-02-19 | 0 | Details |
| US2394837A | Apparatus for assembling articles | Expired / Lapsed | 1943-02-24 | 1946-02-12 | 0 | Details |
| US2393236A | Subscribers' line testing system | Expired / Lapsed | 1944-09-15 | 1946-01-22 | 0 | Details |
| US2392434A | Voltage regulator | Expired / Lapsed | 1943-09-17 | 1946-01-08 | 0 | Details |
| US2392350A | Ultrasonic cell | Expired / Lapsed | 1942-12-02 | 1946-01-08 | 0 | Details |
| US2392356A | Telegraph system | Expired / Lapsed | 1941-05-31 | 1946-01-08 | 0 | Details |
| US2391280A | Method of forming layers for electronic cathodes | Expired / Lapsed | 1942-11-26 | 1945-12-18 | 0 | Details |
| US2389725A | Method of and apparatus for applying material to advancing … | Expired / Lapsed | 1941-05-31 | 1945-11-27 | 0 | Details |
| US2389082A | Code calling signal | Expired / Lapsed | 1943-10-14 | 1945-11-13 | 0 | Details |
| US2388662A | Liquid measuring apparatus | Expired / Lapsed | 1941-12-09 | 1945-11-13 | 0 | Details |
| US2388598A | Method of making coils | Expired / Lapsed | 1943-11-12 | 1945-11-06 | 0 | Details |
| US2386903A | Temperature control apparatus | Expired / Lapsed | 1941-07-31 | 1945-10-16 | 0 | Details |
| US2386763A | Record controlled system | Expired / Lapsed | 1940-08-07 | 1945-10-16 | 0 | Details |
| US2385279A | Distant talking loud-speaker telephone system | Expired / Lapsed | 1943-01-27 | 1945-09-18 | 0 | Details |
| US2384456A | Radio receiving system | Expired / Lapsed | 1944-05-23 | 1945-09-11 | 0 | Details |
| US2384379A | Electrical impulse counting circuits | Expired / Lapsed | 1943-03-13 | 1945-09-04 | 0 | Details |
| US2383826A | Line usage recorder circuit | Expired / Lapsed | 1944-03-21 | 1945-08-28 | 0 | Details |
| US2382994A | Electric maneuvering board | Expired / Lapsed | 1943-12-11 | 1945-08-21 | 0 | Details |
| US2382200A | Molding apparatus | Expired / Lapsed | 1944-02-22 | 1945-08-14 | 0 | Details |
| US2381920A | Telemetric device | Expired / Lapsed | 1944-02-17 | 1945-08-14 | 0 | Details |
| US2382251A | Telegraph perforator-transmitter | Expired / Lapsed | 1943-08-25 | 1945-08-14 | 0 | Details |
| US2382863A | Article handling apparatus | Expired / Lapsed | 1943-03-02 | 1945-08-14 | 0 | Details |
| US2381871A | Communication system | Expired / Lapsed | 1941-03-15 | 1945-08-14 | 0 | Details |
| US2380982A | Electronic commutation of currents | Expired / Lapsed | 1942-11-12 | 1945-08-07 | 0 | Details |
| US2379942A | Cable terminating means | Expired / Lapsed | 1942-12-31 | 1945-07-10 | 0 | Details |
| US2379694A | Stabilized oscillator | Expired / Lapsed | 1943-10-07 | 1945-07-03 | 0 | Details |
| US2379715A | Communication system | Expired / Lapsed | 1942-10-09 | 1945-07-03 | 0 | Details |
| US2379744A | Electric circuit arrangement employing delay networks | Expired / Lapsed | 1942-03-31 | 1945-07-03 | 0 | Details |
| US2379069A | Automatic line testing and switching circuits | Expired / Lapsed | 1943-07-24 | 1945-06-26 | 0 | Details |
| US2379262A | Electric control circuit | Expired / Lapsed | 1943-03-31 | 1945-06-26 | 0 | Details |
| US2379047A | Bridging conductor | Expired / Lapsed | 1942-05-01 | 1945-06-26 | 0 | Details |
| US2375273A | Electric oscillation generating circuit including a thermor… | Expired / Lapsed | 1941-07-31 | 1945-05-08 | 0 | Details |
| US2375272A | Electric cable | Expired / Lapsed | 1941-02-15 | 1945-05-08 | 0 | Details |
| US2373208A | Voltage regulation | Expired / Lapsed | 1943-03-02 | 1945-04-10 | 0 | Details |
| US2373624A | Negative resistance loading | Expired / Lapsed | 1943-01-27 | 1945-04-10 | 0 | Details |
| US2373569A | Wave translating system | Expired / Lapsed | 1943-01-23 | 1945-04-10 | 0 | Details |
| US2373160A | Resistor having a high temperature coefficient of resistance | Expired / Lapsed | 1943-01-07 | 1945-04-10 | 0 | Details |
| US2373134A | Signaling system | Expired / Lapsed | 1942-08-06 | 1945-04-10 | 0 | Details |
| US2373383A | Self-regulating rectifier | Expired / Lapsed | 1941-06-28 | 1945-04-10 | 0 | Details |
| US2372193A | Producing and transmitting electromagnetic waves | Expired / Lapsed | 1940-06-05 | 1945-03-27 | 0 | Details |
| US2371972A | Signaling system | Expired / Lapsed | 1944-02-22 | 1945-03-20 | 0 | Details |
| US2371613A | Piezoelectric crystal apparatus | Expired / Lapsed | 1942-12-31 | 1945-03-20 | 0 | Details |
| US2370727A | Time measuring system | Expired / Lapsed | 1942-12-11 | 1945-03-06 | 0 | Details |
| US2370385A | Method of acoustic measurement and apparatus therefor | Expired / Lapsed | 1942-11-17 | 1945-02-27 | 0 | Details |
| US2369935A | Automatic telegraph transmitter system | Expired / Lapsed | 1942-05-14 | 1945-02-20 | 0 | Details |
| US2369663A | Synchronizing system | Expired / Lapsed | 1942-02-28 | 1945-02-20 | 0 | Details |
| US2369808A | Short-wave radio transmission | Expired / Lapsed | 1940-06-08 | 1945-02-20 | 0 | Details |
| US2369030A | Amplifier circuit | Expired / Lapsed | 1942-07-07 | 1945-02-06 | 0 | Details |
| US2369045A | Electric heating unit | Expired / Lapsed | 1942-01-01 | 1945-02-06 | 0 | Details |
| US2368031A | Electron discharge device | Expired / Lapsed | 1940-03-15 | 1945-01-23 | 0 | Details |
| US2367509A | High or low voltage detector | Expired / Lapsed | 1943-02-20 | 1945-01-16 | 0 | Details |
| US2367522A | Signaling system | Expired / Lapsed | 1942-10-02 | 1945-01-16 | 0 | Details |
| US2366954A | Method of making piezoelectric crystals | Expired / Lapsed | 1943-01-09 | 1945-01-09 | 0 | Details |
| US2366733A | Communication system | Expired / Lapsed | 1941-08-28 | 1945-01-09 | 0 | Details |
| US2364446A | Card translator | Expired / Lapsed | 1944-01-18 | 1944-12-05 | 0 | Details |
| US2364190A | Measuring system and circuit | Expired / Lapsed | 1941-10-29 | 1944-12-05 | 0 | Details |
| US2363583A | Two-way radio communication | Expired / Lapsed | 1942-12-16 | 1944-11-28 | 0 | Details |
| US2363659A | Electric circuit | Expired / Lapsed | 1942-01-31 | 1944-11-28 | 0 | Details |
| US2363781A | Apparatus for and method of applying metallic coatings by t… | Expired / Lapsed | 1940-08-29 | 1944-11-28 | 0 | Details |
| US2363208A | Control device | Expired / Lapsed | 1942-11-12 | 1944-11-21 | 0 | Details |
| US2363062A | Signaling system | Expired / Lapsed | 1941-11-26 | 1944-11-21 | 0 | Details |
| US2362228A | Method of forming contacts on metal oxide-metal rectifiers | Expired / Lapsed | 1941-06-12 | 1944-11-07 | 0 | Details |
| US2360932A | Negative resistance loading | Expired / Lapsed | 1942-04-25 | 1944-10-24 | 0 | Details |
| US2360940A | Negative resistance loading | Expired / Lapsed | 1942-04-25 | 1944-10-24 | 0 | Details |
| US2360523A | Electrical measuring apparatus | Expired / Lapsed | 1943-05-15 | 1944-10-17 | 0 | Details |
| US2360063A | Composite article | Expired / Lapsed | 1942-03-13 | 1944-10-10 | 0 | Details |
| US2360233A | Thermistor as amplifier for low frequency signals | Expired / Lapsed | 1941-12-10 | 1944-10-10 | 0 | Details |
| US2357591A | Joint for metal sheath cables | Expired / Lapsed | 1942-05-01 | 1944-09-05 | 0 | Details |
| US2356519A | Communication system | Expired / Lapsed | 1942-10-09 | 1944-08-22 | 0 | Details |
| US2355903A | Signaling system | Expired / Lapsed | 1942-06-27 | 1944-08-15 | 0 | Details |
| US2353732A | Wire connector | Expired / Lapsed | 1942-06-30 | 1944-07-18 | 0 | Details |
| US2353638A | Conveyer system | Expired / Lapsed | 1942-04-10 | 1944-07-18 | 0 | Details |
| US2352451A | Frequency converter | Expired / Lapsed | 1942-02-07 | 1944-06-27 | 0 | Details |
| US2352056A | Thermally controlled resistor | Expired / Lapsed | 1942-09-23 | 1944-06-20 | 0 | Details |
| US2351446A | Sender load control | Expired / Lapsed | 1942-12-22 | 1944-06-13 | 0 | Details |
| US2351201A | Method of and means for measuring | Expired / Lapsed | 1942-07-16 | 1944-06-13 | 0 | Details |
| US2351321A | Apparatus for the manufacture of electrolytic condensers | Expired / Lapsed | 1941-09-27 | 1944-06-13 | 0 | Details |
| US2350887A | Method of manufacturing parts for electrical apparatus | Expired / Lapsed | 1941-11-28 | 1944-06-06 | 0 | Details |
| US2350888A | Selecting system | Expired / Lapsed | 1941-11-21 | 1944-06-06 | 0 | Details |
| US2350916A | Ultra short wave antenna system | Expired / Lapsed | 1940-05-17 | 1944-06-06 | 0 | Details |
| US2350180A | Telegraph system | Expired / Lapsed | 1942-10-17 | 1944-05-30 | 0 | Details |
| US2349129A | Dialing system | Expired / Lapsed | 1942-07-01 | 1944-05-16 | 0 | Details |
| US2349144A | Telephone booth | Expired / Lapsed | 1941-12-04 | 1944-05-16 | 0 | Details |
| US2348592A | Telephone housing detail | Expired / Lapsed | 1942-09-26 | 1944-05-09 | 0 | Details |
| US2348045A | Electron discharge device and method of manufacture | Expired / Lapsed | 1942-01-01 | 1944-05-02 | 0 | Details |
| US2347777A | Signaling circuit | Expired / Lapsed | 1941-12-23 | 1944-05-02 | 0 | Details |
| US2347831A | Communication system | Expired / Lapsed | 1941-08-28 | 1944-05-02 | 0 | Details |
| US2347733A | Switching device | Expired / Lapsed | 1941-06-06 | 1944-05-02 | 0 | Details |
| US2347108A | Call transmitter for telephone signaling systems | Expired / Lapsed | 1943-02-05 | 1944-04-18 | 0 | Details |
| US2347098A | Electrical wave modulation | Expired / Lapsed | 1942-01-09 | 1944-04-18 | 0 | Details |
| US2345932A | Measuring apparatus | Expired / Lapsed | 1941-03-26 | 1944-04-04 | 0 | Details |
| US2345491A | Wave transmission network | Expired / Lapsed | 1941-11-25 | 1944-03-28 | 0 | Details |
| US2345048A | Communication system | Expired / Lapsed | 1941-11-13 | 1944-03-28 | 0 | Details |
| US2345317A | Satellite telegraph switching system | Expired / Lapsed | 1941-05-17 | 1944-03-28 | 0 | Details |
| US2344792A | Motor control mechanism for printing telegraph apparatus | Expired / Lapsed | 1941-11-27 | 1944-03-21 | 0 | Details |
| US2344633A | Impulse repeater | Expired / Lapsed | 1941-11-13 | 1944-03-21 | 0 | Details |
| US2343988A | Cathode ray intensity control circuit | Expired / Lapsed | 1943-02-24 | 1944-03-14 | 0 | Details |
| US2344454A | Training device | Expired / Lapsed | 1942-12-07 | 1944-03-14 | 0 | Details |
| US2344340A | Apparatus for applying tape upon articles | Expired / Lapsed | 1942-05-29 | 1944-03-14 | 0 | Details |
| US2343539A | Stabilized oscillator | Expired / Lapsed | 1942-01-16 | 1944-03-07 | 0 | Details |
| US2342886A | Printing telegraph apparatus and system | Expired / Lapsed | 1941-02-25 | 1944-02-29 | 0 | Details |
| US2343059A | Piezoelectric crystal apparatus | Expired / Lapsed | 1940-09-18 | 1944-02-29 | 0 | Details |
| US2342552A | Switching apparatus | Expired / Lapsed | 1943-02-20 | 1944-02-22 | 0 | Details |
| US2342245A | Electric signaling | Expired / Lapsed | 1942-06-27 | 1944-02-22 | 0 | Details |
| US2342238A | Variable attenuation circuits | Expired / Lapsed | 1941-12-31 | 1944-02-22 | 0 | Details |
| US2342395A | Control system for sound films | Expired / Lapsed | 1941-10-22 | 1944-02-22 | 0 | Details |
| US2340576A | Telegraph system | Expired / Lapsed | 1942-06-04 | 1944-02-01 | 0 | Details |
| US2339633A | Variable selective system | Expired / Lapsed | 1942-03-23 | 1944-01-18 | 0 | Details |
| US2339406A | Electrical transmission system | Expired / Lapsed | 1941-05-31 | 1944-01-18 | 0 | Details |
| US2339194A | Material handling apparatus | Expired / Lapsed | 1941-10-17 | 1944-01-11 | 0 | Details |
| US2338218A | Time-measuring device | Expired / Lapsed | 1942-12-11 | 1944-01-04 | 0 | Details |
| US2338636A | Automatic billing system | Expired / Lapsed | 1937-12-08 | 1944-01-04 | 0 | Details |
| US2337886A | Telegraph system | Expired / Lapsed | 1942-06-20 | 1943-12-28 | 0 | Details |
| US2337423A | Negative feed-back amplifier | Expired / Lapsed | 1942-10-01 | 1943-12-21 | 0 | Details |
| US2336543A | Digit signal translator | Expired / Lapsed | 1942-07-31 | 1943-12-14 | 0 | Details |
| US2336373A | Teletypewriter switching system | Expired / Lapsed | 1940-06-15 | 1943-12-07 | 0 | Details |
| US2334534A | Teletypewriter | Expired / Lapsed | 1942-12-02 | 1943-11-16 | 0 | Details |
| US2332912A | Telephone system | Expired / Lapsed | 1942-05-01 | 1943-10-26 | 0 | Details |
| US2332622A | Electron discharge device | Expired / Lapsed | 1941-10-11 | 1943-10-26 | 0 | Details |
| US2332596A | Resistor device | Expired / Lapsed | 1941-08-30 | 1943-10-26 | 0 | Details |
| US2332430A | Two-way telephone system | Expired / Lapsed | 1942-07-16 | 1943-10-19 | 0 | Details |
| US2332102A | Negative transconductance tube oscillator | Expired / Lapsed | 1941-11-26 | 1943-10-19 | 0 | Details |
| US2332091A | Ventilating system for telephone booths | Expired / Lapsed | 1941-05-03 | 1943-10-19 | 0 | Details |
| US2332448A | Telephone system | Expired / Lapsed | 1940-10-22 | 1943-10-19 | 0 | Details |
| US2332073A | Electric circuit control | Expired / Lapsed | 1940-07-11 | 1943-10-19 | 0 | Details |
| US2329764A | Relay circuit | Expired / Lapsed | 1941-08-26 | 1943-09-21 | 0 | Details |
| US2329466A | Call transmitter | Expired / Lapsed | 1940-12-17 | 1943-09-14 | 0 | Details |
| US2329504A | Electric timing device | Expired / Lapsed | 1940-01-06 | 1943-09-14 | 0 | Details |
| US2329010A | Power supply system | Expired / Lapsed | 1942-07-22 | 1943-09-07 | 0 | Details |
| US2328750A | Test device | Expired / Lapsed | 1942-04-29 | 1943-09-07 | 0 | Details |
| US2328478A | Piezoelectric transducer | Expired / Lapsed | 1940-03-30 | 1943-08-31 | 0 | Details |
| US2327792A | Selector | Expired / Lapsed | 1941-12-09 | 1943-08-24 | 0 | Details |
| US2327275A | Signaling system | Expired / Lapsed | 1941-08-28 | 1943-08-17 | 0 | Details |
| US2326572A | Holder for electrically heated tools | Expired / Lapsed | 1942-07-01 | 1943-08-10 | 0 | Details |
| US2326478A | Selection system | Expired / Lapsed | 1942-02-17 | 1943-08-10 | 0 | Details |
| US2326290A | Alarm and testing circuit | Expired / Lapsed | 1941-07-30 | 1943-08-10 | 0 | Details |
| US2326313A | Alarm circuit | Expired / Lapsed | 1941-02-27 | 1943-08-10 | 0 | Details |
| US2325952A | Signaling device | Expired / Lapsed | 1941-12-11 | 1943-08-03 | 0 | Details |
| US2324809A | Soldering method | Expired / Lapsed | 1942-07-22 | 1943-07-20 | 0 | Details |
| US2324534A | Television transmitter | Expired / Lapsed | 1941-09-30 | 1943-07-20 | 0 | Details |
| US2324797A | Differentiating amplifier | Expired / Lapsed | 1941-09-17 | 1943-07-20 | 0 | Details |
| US2322756A | Method of impregnation | Expired / Lapsed | 1941-07-11 | 1943-06-29 | 0 | Details |
| US2322851A | Magnetic switch hook | Expired / Lapsed | 1941-01-24 | 1943-06-29 | 0 | Details |
| US2322653A | Telautographic device | Expired / Lapsed | 1940-01-05 | 1943-06-22 | 0 | Details |
| US2320076A | Selecting system | Expired / Lapsed | 1941-11-21 | 1943-05-25 | 0 | Details |
| US2319965A | Variable frequency bridge stabilized oscillator | Expired / Lapsed | 1941-06-14 | 1943-05-25 | 0 | Details |
| US2319940A | Gravitational force measuring apparatus | Expired / Lapsed | 1939-09-12 | 1943-05-25 | 0 | Details |
| US2319744A | Shielding for communication circuits | Expired / Lapsed | 1941-10-30 | 1943-05-18 | 0 | Details |
| US2319333A | Service observing system | Expired / Lapsed | 1941-06-14 | 1943-05-18 | 0 | Details |
| US2319339A | Signaling system | Expired / Lapsed | 1940-05-22 | 1943-05-18 | 0 | Details |
| US2318533A | Apparatus for heating material | Expired / Lapsed | 1940-12-06 | 1943-05-04 | 0 | Details |
| US2318508A | Material feeding apparatus | Expired / Lapsed | 1940-07-10 | 1943-05-04 | 0 | Details |
| US2317471A | Selection system | Expired / Lapsed | 1942-02-17 | 1943-04-27 | 0 | Details |
| US2315720A | Electrical connecting device | Expired / Lapsed | 1941-03-15 | 1943-04-06 | 0 | Details |
| US2315621A | Electron camera | Expired / Lapsed | 1940-09-24 | 1943-04-06 | 0 | Details |
| US2315445A | Regulated rectifier circuit | Expired / Lapsed | 1940-08-31 | 1943-03-30 | 0 | Details |
| US2315434A | Transmission system | Expired / Lapsed | 1940-07-03 | 1943-03-30 | 0 | Details |
| US2314851A | Power factor measuring system | Expired / Lapsed | 1942-04-30 | 1943-03-23 | 0 | Details |
| US2314409A | Magnetic coil structure | Expired / Lapsed | 1940-09-28 | 1943-03-23 | 0 | Details |
| US2314471A | Two-way television and speech television | Expired / Lapsed | 1940-08-24 | 1943-03-23 | 0 | Details |
| US2312954A | Observer controlled television system | Expired / Lapsed | 1941-06-04 | 1943-03-02 | 0 | Details |
| US2312723A | Electron discharge device | Expired / Lapsed | 1939-08-16 | 1943-03-02 | 0 | Details |
| US2311801A | Thermal time delay relay | Expired / Lapsed | 1941-07-11 | 1943-02-23 | 0 | Details |
| US2311807A | Electron discharge device circuit | Expired / Lapsed | 1940-08-10 | 1943-02-23 | 0 | Details |
| US2310452A | Switching system | Expired / Lapsed | 1941-06-05 | 1943-02-09 | 0 | Details |
| US2309703A | Alternating current generator | Expired / Lapsed | 1941-05-21 | 1943-02-02 | 0 | Details |
| US2309081A | Electrically conductive device | Expired / Lapsed | 1941-10-01 | 1943-01-26 | 0 | Details |
| US2309525A | Electric signaling | Expired / Lapsed | 1941-01-21 | 1943-01-26 | 0 | Details |
| US2307989A | Sound signal | Expired / Lapsed | 1942-03-24 | 1943-01-12 | 0 | Details |
| US2307868A | Binary counter | Expired / Lapsed | 1941-11-26 | 1943-01-12 | 0 | Details |
| US2308381A | Two-way television transmission | Expired / Lapsed | 1939-12-29 | 1943-01-12 | 0 | Details |
| US2307728A | Signaling system | Expired / Lapsed | 1940-08-10 | 1943-01-05 | 0 | Details |
| US2306435A | Frequency compression | Expired / Lapsed | 1941-01-17 | 1942-12-29 | 0 | Details |
| US2306067A | Telephone system | Expired / Lapsed | 1940-10-16 | 1942-12-22 | 0 | Details |
| US2304613A | Delayed operation circuit | Expired / Lapsed | 1941-04-12 | 1942-12-08 | 0 | Details |
| US2304061A | Switching device for telephone instruments | Expired / Lapsed | 1940-05-15 | 1942-12-08 | 0 | Details |
| US2304044A | Voltage regulation and rectification | Expired / Lapsed | 1941-08-15 | 1942-12-01 | 0 | Details |
| US2303377A | Communication system with voiceoperated switching mechanisms | Expired / Lapsed | 1941-07-23 | 1942-12-01 | 0 | Details |
| US2303497A | Duplex metal body | Expired / Lapsed | 1941-05-09 | 1942-12-01 | 0 | Details |
| US2303952A | Relay | Expired / Lapsed | 1940-10-05 | 1942-12-01 | 0 | Details |
| US2303054A | Polar signal test transmitter | Expired / Lapsed | 1941-08-06 | 1942-11-24 | 0 | Details |
| US2303016A | Impulse counting circuit | Expired / Lapsed | 1941-06-20 | 1942-11-24 | 0 | Details |
| US2302767A | Terminal for electrical conductors | Expired / Lapsed | 1940-12-21 | 1942-11-24 | 0 | Details |
| US2301929A | Radio distance and altitude indicating system | Expired / Lapsed | 1941-04-18 | 1942-11-17 | 0 | Details |
| US2302334A | Telephone system | Expired / Lapsed | 1940-03-30 | 1942-11-17 | 0 | Details |
| US2301223A | Transmission system | Expired / Lapsed | 1941-05-13 | 1942-11-10 | 0 | Details |
| US2301343A | Regulated rectifier | Expired / Lapsed | 1940-10-19 | 1942-11-10 | 0 | Details |
| US2301199A | Facsimile system | Expired / Lapsed | 1940-04-26 | 1942-11-10 | 0 | Details |
| US2300638A | Alternating current generator | Expired / Lapsed | 1941-05-21 | 1942-11-03 | 0 | Details |
| US2300505A | Selective system | Expired / Lapsed | 1940-10-31 | 1942-11-03 | 0 | Details |
| US2300320A | Device for reproducing tone frequencies | Expired / Lapsed | 1941-05-27 | 1942-10-27 | 0 | Details |
| US2300366A | Signal transmission system | Expired / Lapsed | 1940-11-28 | 1942-10-27 | 0 | Details |
| US2299815A | Gas detector | Expired / Lapsed | 1940-11-05 | 1942-10-27 | 0 | Details |
| US2300133A | Broad band amplifier | Expired / Lapsed | 1940-09-20 | 1942-10-27 | 0 | Details |
| US2300044A | Telephone subscriber's station | Expired / Lapsed | 1940-07-23 | 1942-10-27 | 0 | Details |
| US2299821A | Signaling system | Expired / Lapsed | 1940-04-05 | 1942-10-27 | 0 | Details |
| US2299229A | Selecting system | Expired / Lapsed | 1941-11-26 | 1942-10-20 | 0 | Details |
| US2299212A | Telephone system | Expired / Lapsed | 1941-07-03 | 1942-10-20 | 0 | Details |
| US2299252A | Frequency detector | Expired / Lapsed | 1941-05-29 | 1942-10-20 | 0 | Details |
| US2299279A | Signaling system | Expired / Lapsed | 1941-04-19 | 1942-10-20 | 0 | Details |
| US2299689A | Manufacture of electrical conductors | Expired / Lapsed | 1941-03-05 | 1942-10-20 | 0 | Details |
| US2298519A | Telephone system | Expired / Lapsed | 1940-06-21 | 1942-10-13 | 0 | Details |
| US2298722A | Impulse transmission system | Expired / Lapsed | 1939-06-30 | 1942-10-13 | 0 | Details |
| US2298324A | Electrical conductor | Expired / Lapsed | 1934-09-29 | 1942-10-13 | 0 | Details |
| US2298192A | Thermistor circuit | Expired / Lapsed | 1941-12-26 | 1942-10-06 | 0 | Details |
| US2295153A | Two-way signal transmission system | Expired / Lapsed | 1941-06-10 | 1942-09-08 | 0 | Details |
| US2294907A | Telephone system | Expired / Lapsed | 1941-01-17 | 1942-09-08 | 0 | Details |
| US2294464A | Impulse transmitter | Expired / Lapsed | 1938-04-09 | 1942-09-01 | 0 | Details |
| US2294114A | Electrostatic scanning | Expired / Lapsed | 1941-05-31 | 1942-08-25 | 0 | Details |
| US2293869A | Signaling system | Expired / Lapsed | 1940-09-14 | 1942-08-25 | 0 | Details |
| US2293870A | Electro-optical image production | Expired / Lapsed | 1940-02-03 | 1942-08-25 | 0 | Details |
| US2292388A | Rochelle salt piezoelectric crystal apparatus | Expired / Lapsed | 1941-05-23 | 1942-08-11 | 0 | Details |
| US2292890A | Conveyer control | Expired / Lapsed | 1940-07-05 | 1942-08-11 | 0 | Details |
| US2291615A | Telephone system | Expired / Lapsed | 1941-07-19 | 1942-08-04 | 0 | Details |
| US2291224A | Selecting system | Expired / Lapsed | 1941-02-08 | 1942-07-28 | 0 | Details |
| US2291040A | Switching system | Expired / Lapsed | 1941-02-08 | 1942-07-28 | 0 | Details |
| US2289746A | Teletypewriter "answer back" circuit | Expired / Lapsed | 1940-03-26 | 1942-07-14 | 0 | Details |
| US2289830A | Circuit closing device | Expired / Lapsed | 1938-03-29 | 1942-07-14 | 0 | Details |
| US2289048A | Power line carrier frequency telephone system | Expired / Lapsed | 1941-06-19 | 1942-07-07 | 0 | Details |
| US2288817A | Oscillation modulator | Expired / Lapsed | 1939-07-18 | 1942-07-07 | 0 | Details |
| US2288025A | Automatic frequency control system | Expired / Lapsed | 1940-08-03 | 1942-06-30 | 0 | Details |
| US2287881A | Telephone system | Expired / Lapsed | 1939-02-24 | 1942-06-30 | 0 | Details |
| US2287077A | Volume range control in signal transmission systems | Expired / Lapsed | 1941-07-19 | 1942-06-23 | 0 | Details |
| US2287587A | Light modulating apparatus | Expired / Lapsed | 1939-11-02 | 1942-06-23 | 0 | Details |
| US2287174A | Relative phase measuring circuit and method | Expired / Lapsed | 1939-09-16 | 1942-06-23 | 0 | Details |
| US2286839A | Directive antenna system | Expired / Lapsed | 1939-12-20 | 1942-06-16 | 0 | Details |
| US2285832A | Feedback amplifier | Expired / Lapsed | 1940-04-20 | 1942-06-09 | 0 | Details |
| US2285796A | Gaseous discharge device | Expired / Lapsed | 1939-10-19 | 1942-06-09 | 0 | Details |
| US2284753A | Piezoelectric crystal apparatus | Expired / Lapsed | 1940-09-20 | 1942-06-02 | 0 | Details |
| US2285017A | Coating apparatus | Expired / Lapsed | 1940-02-08 | 1942-06-02 | 0 | Details |
| US2285166A | Tension gauge | Expired / Lapsed | 1940-01-11 | 1942-06-02 | 0 | Details |
| US2284402A | Modulation circuit | Expired / Lapsed | 1940-08-27 | 1942-05-26 | 0 | Details |
| US2284444A | Demodulation circuit | Expired / Lapsed | 1940-08-27 | 1942-05-26 | 0 | Details |
| US2284612A | Phase control in electrical transmission | Expired / Lapsed | 1940-01-06 | 1942-05-26 | 0 | Details |
| US2283935A | Transmission, radiation, and reception of electromagnetic w… | Expired / Lapsed | 1938-04-29 | 1942-05-26 | 0 | Details |
| US2283616A | Oscillographic method of frequency setting or measurement | Expired / Lapsed | 1940-08-03 | 1942-05-19 | 0 | Details |
| US2283568A | Ultra high frequency system | Expired / Lapsed | 1940-06-18 | 1942-05-19 | 0 | Details |
| US2282465A | Speech transmission system | Expired / Lapsed | 1941-02-27 | 1942-05-12 | 0 | Details |
| US2283148A | Modulation of cathode ray devices | Expired / Lapsed | 1941-02-14 | 1942-05-12 | 0 | Details |
| US2281717A | Electron discharge apparatus | Expired / Lapsed | 1941-01-21 | 1942-05-05 | 0 | Details |
| US2281542A | Electrical conductor | Expired / Lapsed | 1939-03-03 | 1942-05-05 | 0 | Details |
| US2281461A | Temperature compensating means | Expired / Lapsed | 1941-09-24 | 1942-04-28 | 0 | Details |
| US2281040A | Thermionic relay circuit | Expired / Lapsed | 1941-04-26 | 1942-04-28 | 0 | Details |
| US2281312A | Wave translation | Expired / Lapsed | 1941-02-25 | 1942-04-28 | 0 | Details |
| US2280949A | Electric signaling | Expired / Lapsed | 1941-01-21 | 1942-04-28 | 0 | Details |
| US2281238A | Feedback amplifier | Expired / Lapsed | 1940-05-01 | 1942-04-28 | 0 | Details |
| US2281396A | Relay selecting circuit | Expired / Lapsed | 1940-04-03 | 1942-04-28 | 0 | Details |
| US2280257A | Resistor device and method of making the same | Expired / Lapsed | 1939-07-25 | 1942-04-21 | 0 | Details |
| US2279319A | Electric wave circuit | Expired / Lapsed | 1941-05-28 | 1942-04-14 | 0 | Details |
| US2278504A | Telephone signaling system | Expired / Lapsed | 1941-03-08 | 1942-04-07 | 0 | Details |
| US2278940A | Picture reproduction | Expired / Lapsed | 1938-01-03 | 1942-04-07 | 0 | Details |
| US2277228A | Telephone system | Expired / Lapsed | 1940-11-29 | 1942-03-24 | 0 | Details |
| US2277134A | Brake | Expired / Lapsed | 1940-06-28 | 1942-03-24 | 0 | Details |
| US2277206A | Key sender | Expired / Lapsed | 1940-06-22 | 1942-03-24 | 0 | Details |
| US2277470A | Automatic toll ticketing system | Expired / Lapsed | 1939-01-19 | 1942-03-24 | 0 | Details |
| US2276665A | Pulse regenerator | Expired / Lapsed | 1940-10-25 | 1942-03-17 | 0 | Details |
| US2276986A | Latex | Expired / Lapsed | 1939-09-09 | 1942-03-17 | 0 | Details |
| US2275452A | Stabilized vacuum tube oscillator | Expired / Lapsed | 1939-06-24 | 1942-03-10 | 0 | Details |
| US2275977A | Means for calibrating scales | Expired / Lapsed | 1938-09-28 | 1942-03-10 | 0 | Details |
| US2275122A | Piezoelectric crystal apparatus | Expired / Lapsed | 1940-06-05 | 1942-03-03 | 0 | Details |
| US2274709A | Electro-optical image production | Expired / Lapsed | 1936-09-02 | 1942-03-03 | 0 | Details |
| US2273945A | Two-way speech transmission | Expired / Lapsed | 1941-04-16 | 1942-02-24 | 0 | Details |
| US2274083A | Sender control system | Expired / Lapsed | 1940-09-11 | 1942-02-24 | 0 | Details |
| US2274592A | Resistance material and method of making the same | Expired / Lapsed | 1939-06-23 | 1942-02-24 | 0 | Details |
| US2273433A | Cathode ray tube | Expired / Lapsed | 1940-04-10 | 1942-02-17 | 0 | Details |
| US2273793A | Cathode ray tube | Expired / Lapsed | 1940-04-10 | 1942-02-17 | 0 | Details |
| US2273432A | Electron discharge device circuits | Expired / Lapsed | 1940-01-03 | 1942-02-17 | 0 | Details |
| US2273447A | Unidirective energy radiating system | Expired / Lapsed | 1939-09-07 | 1942-02-17 | 0 | Details |
| US2273165A | Tariff determining equipment for telephone systems | Expired / Lapsed | 1939-02-25 | 1942-02-17 | 0 | Details |
| US2273193A | Wave transmission and shaping | Expired / Lapsed | 1938-10-07 | 1942-02-17 | 0 | Details |
| US2273704A | Electrical conducting material | Expired / Lapsed | 1935-10-10 | 1942-02-17 | 0 | Details |
| US2272994A | Piezoelectric crystal element | Expired / Lapsed | 1940-12-14 | 1942-02-10 | 0 | Details |
| US2272432A | Electrical connector | Expired / Lapsed | 1940-11-28 | 1942-02-10 | 0 | Details |
| US2272998A | Slow-operate electrical circuit | Expired / Lapsed | 1940-10-23 | 1942-02-10 | 0 | Details |
| US2272701A | Electric wave transmission system | Expired / Lapsed | 1940-10-05 | 1942-02-10 | 0 | Details |
| US2272718A | Die casting machine | Expired / Lapsed | 1940-06-05 | 1942-02-10 | 0 | Details |
| US2270906A | Piezoelectric crystal apparatus | Expired / Lapsed | 1940-11-16 | 1942-01-27 | 0 | Details |
| US2271200A | Wave filter | Expired / Lapsed | 1939-07-19 | 1942-01-27 | 0 | Details |
| US2269692A | Alarm signaling system | Expired / Lapsed | 1937-08-31 | 1942-01-13 | 0 | Details |
| US2269408A | Gain control circuits | Expired / Lapsed | 1940-09-14 | 1942-01-06 | 0 | Details |
| US2267936A | Impulse code converter | Expired / Lapsed | 1940-07-27 | 1941-12-30 | 0 | Details |
| US2267827A | Electric signaling system | Expired / Lapsed | 1939-07-26 | 1941-12-30 | 0 | Details |
| US2268203A | Calculating machine | Expired / Lapsed | 1937-11-06 | 1941-12-30 | 0 | Details |
| US2266925A | Electrical coil | Expired / Lapsed | 1940-08-17 | 1941-12-23 | 0 | Details |
| US2266416A | Control apparatus | Expired / Lapsed | 1939-01-14 | 1941-12-16 | 0 | Details |
| US2265844A | Calling line identification circuit | Expired / Lapsed | 1940-07-03 | 1941-12-09 | 0 | Details |
| US2265056A | Radio telephone system | Expired / Lapsed | 1940-09-27 | 1941-12-02 | 0 | Details |
| US2264746A | Electromagnetic switch | Expired / Lapsed | 1940-06-27 | 1941-12-02 | 0 | Details |
| US2264124A | Relay | Expired / Lapsed | 1940-06-27 | 1941-11-25 | 0 | Details |
| US2261272A | Radiant energy distance measuring system | Expired / Lapsed | 1940-08-07 | 1941-11-04 | 0 | Details |
| US2261772A | Apparatus for measuring articles | Expired / Lapsed | 1940-01-11 | 1941-11-04 | 0 | Details |
| US2261412A | Fabrication of duplex metal bodies | Expired / Lapsed | 1938-10-27 | 1941-11-04 | 0 | Details |
| US2260709A | Television system | Expired / Lapsed | 1936-03-04 | 1941-10-28 | 0 | Details |
| US2260160A | Location and identification of faults in signaling transmis… | Expired / Lapsed | 1940-04-26 | 1941-10-21 | 0 | Details |
| US2260202A | Sound film recording or reproducing device | Expired / Lapsed | 1940-04-03 | 1941-10-21 | 0 | Details |
| US2258662A | Sound transmission system | Expired / Lapsed | 1940-04-05 | 1941-10-14 | 0 | Details |
| US2258651A | Telephone system | Expired / Lapsed | 1940-02-21 | 1941-10-14 | 0 | Details |
| US2258646A | Resistance material | Expired / Lapsed | 1939-05-17 | 1941-10-14 | 0 | Details |
| US2259000A | Transmission of frequency modulated waves | Expired / Lapsed | 1938-05-21 | 1941-10-14 | 0 | Details |
| US2257795A | Electron discharge apparatus and circuits | Expired / Lapsed | 1939-05-27 | 1941-10-07 | 0 | Details |
| US2258128A | Wave translating system | Expired / Lapsed | 1938-12-20 | 1941-10-07 | 0 | Details |
| US2257894A | Telephone system | Expired / Lapsed | 1938-11-02 | 1941-10-07 | 0 | Details |
| US2257568A | Communication system | Expired / Lapsed | 1939-06-14 | 1941-09-30 | 0 | Details |
| US2254601A | Automatic measuring of cross talk | Expired / Lapsed | 1940-04-03 | 1941-09-02 | 0 | Details |
| US2253577A | Resistance device | Expired / Lapsed | 1939-04-07 | 1941-08-26 | 0 | Details |
| US2253503A | Generation and transmission of high frequency oscillations | Expired / Lapsed | 1938-08-06 | 1941-08-26 | 0 | Details |
| US2252766A | Signaling system | Expired / Lapsed | 1940-10-17 | 1941-08-19 | 0 | Details |
| US2252899A | Method of manufacturing contact springs | Expired / Lapsed | 1939-11-14 | 1941-08-19 | 0 | Details |
| US2252552A | Luminescent coating | Expired / Lapsed | 1940-07-05 | 1941-08-12 | 0 | Details |
| US2252293A | Modulation system | Expired / Lapsed | 1939-06-14 | 1941-08-12 | 0 | Details |
| US2251332A | Cathode ray device | Expired / Lapsed | 1938-03-31 | 1941-08-05 | 0 | Details |
| US2250528A | Signal translating system and apparatus | Expired / Lapsed | 1939-02-11 | 1941-07-29 | 0 | Details |
| US2250527A | Signal translating apparatus | Expired / Lapsed | 1939-02-11 | 1941-07-29 | 0 | Details |
| US2250104A | Frequency regulation | Expired / Lapsed | 1940-03-30 | 1941-07-22 | 0 | Details |
| US2250100A | Signaling system | Expired / Lapsed | 1939-11-14 | 1941-07-22 | 0 | Details |
| US2250156A | Electrical connection | Expired / Lapsed | 1939-06-02 | 1941-07-22 | 0 | Details |
| US2249950A | Method of preparing linear polyesters | Expired / Lapsed | 1938-05-28 | 1941-07-22 | 0 | Details |
| US2249153A | Testing device | Expired / Lapsed | 1939-05-02 | 1941-07-15 | 0 | Details |
| US2248985A | Electro-optical apparatus | Expired / Lapsed | 1938-08-25 | 1941-07-15 | 0 | Details |
| US2249323A | Testing apparatus | Expired / Lapsed | 1937-08-11 | 1941-07-15 | 0 | Details |
| US2248215A | Radio direction and distance indicating system | Expired / Lapsed | 1940-06-20 | 1941-07-08 | 0 | Details |
| US2248250A | Single side-band modulation | Expired / Lapsed | 1939-09-21 | 1941-07-08 | 0 | Details |
| US2248057A | Electrical cutting device | Expired / Lapsed | 1939-01-25 | 1941-07-08 | 0 | Details |
| US2247442A | Neutralizing arrangement for amplifiers | Expired / Lapsed | 1940-02-02 | 1941-07-01 | 0 | Details |
| US2247666A | Directional antenna system | Expired / Lapsed | 1939-08-02 | 1941-07-01 | 0 | Details |
| US2247662A | Radiant energy distance measuring system | Expired / Lapsed | 1938-11-16 | 1941-07-01 | 0 | Details |
| US2247028A | Telephone booth cooling apparatus | Expired / Lapsed | 1940-10-29 | 1941-06-24 | 0 | Details |
| US2245660A | Radio system | Expired / Lapsed | 1938-10-12 | 1941-06-17 | 0 | Details |
| US2245598A | Wave translation system | Expired / Lapsed | 1938-10-07 | 1941-06-17 | 0 | Details |
| US2244700A | Telephone system | Expired / Lapsed | 1939-09-21 | 1941-06-10 | 0 | Details |
| US2245364A | Cathode ray device | Expired / Lapsed | 1937-05-29 | 1941-06-10 | 0 | Details |
| US2243851A | Wire line transmission | Expired / Lapsed | 1940-06-06 | 1941-06-03 | 0 | Details |
| US2244500A | Telephone system | Expired / Lapsed | 1938-09-30 | 1941-06-03 | 0 | Details |
| US2244004A | Telephone system | Expired / Lapsed | 1938-02-11 | 1941-06-03 | 0 | Details |
| US2243399A | Contact operating device | Expired / Lapsed | 1939-10-04 | 1941-05-27 | 0 | Details |
| US2241591A | Calculating machine | Expired / Lapsed | 1939-05-24 | 1941-05-13 | 0 | Details |
| US2241761A | Electrical coil and a method of making the same | Expired / Lapsed | 1939-02-11 | 1941-05-13 | 0 | Details |
| US2241441A | Manufacture of magnetic bodies | Expired / Lapsed | 1938-07-15 | 1941-05-13 | 0 | Details |
| US2241031A | Telephone system | Expired / Lapsed | 1940-01-23 | 1941-05-06 | 0 | Details |
| US2240929A | Testing apparatus | Expired / Lapsed | 1939-11-22 | 1941-05-06 | 0 | Details |
| US2240941A | Oscillation source of the spark discharge gap type | Expired / Lapsed | 1939-06-20 | 1941-05-06 | 0 | Details |
| US2241228A | Coating machine | Expired / Lapsed | 1939-03-03 | 1941-05-06 | 0 | Details |
| US2241256A | Circuit for cathode ray tubes | Expired / Lapsed | 1937-12-31 | 1941-05-06 | 0 | Details |
| US2239771A | Electrically conductive device and its manufacture | Expired / Lapsed | 1938-05-14 | 1941-04-29 | 0 | Details |
| US2238142A | Teletypewriter switching system | Expired / Lapsed | 1939-07-14 | 1941-04-15 | 0 | Details |
| US2238555A | Voice operated mechanism | Expired / Lapsed | 1939-03-31 | 1941-04-15 | 0 | Details |
| US2237742A | Telephone system | Expired / Lapsed | 1939-11-28 | 1941-04-08 | 0 | Details |
| US2237326A | Apparatus for measuring acceleration | Expired / Lapsed | 1938-02-23 | 1941-04-08 | 0 | Details |
| US2236893A | Radiant energy distance determining system | Expired / Lapsed | 1939-12-30 | 1941-04-01 | 0 | Details |
| US2236690A | Negative impedance circuit | Expired / Lapsed | 1938-03-05 | 1941-04-01 | 0 | Details |
| US2236246A | Telephone system | Expired / Lapsed | 1939-09-15 | 1941-03-25 | 0 | Details |
| US2236172A | Electro-optical system | Expired / Lapsed | 1936-03-04 | 1941-03-25 | 0 | Details |
| US2235132A | Magnetic telegraphone | Expired / Lapsed | 1939-07-29 | 1941-03-18 | 0 | Details |
| US2235126A | Magnetic telegraphone | Expired / Lapsed | 1939-07-13 | 1941-03-18 | 0 | Details |
| US2235153A | Chain start circuit | Expired / Lapsed | 1939-07-11 | 1941-03-18 | 0 | Details |
| US2235667A | Relaxation oscillator | Expired / Lapsed | 1938-12-16 | 1941-03-18 | 0 | Details |
| US2234687A | Balanced vacuum tube circuit | Expired / Lapsed | 1939-11-25 | 1941-03-11 | 0 | Details |
| US2233621A | Pole-piece assembly for telegraphones | Expired / Lapsed | 1939-07-13 | 1941-03-04 | 0 | Details |
| US2233860A | Modulating system | Expired / Lapsed | 1939-04-27 | 1941-03-04 | 0 | Details |
| US2233848A | Audiphone | Expired / Lapsed | 1938-06-30 | 1941-03-04 | 0 | Details |
| US2233384A | Radio receiver | Expired / Lapsed | 1939-12-28 | 1941-02-25 | 0 | Details |
| US2232792A | Method of and apparatus for measuring impedances | Expired / Lapsed | 1939-12-15 | 1941-02-25 | 0 | Details |
| US2232866A | Signaling system | Expired / Lapsed | 1939-11-14 | 1941-02-25 | 0 | Details |
| US2232858A | Frequency meter | Expired / Lapsed | 1939-07-27 | 1941-02-25 | 0 | Details |
| US2232642A | Loading system | Expired / Lapsed | 1939-12-13 | 1941-02-18 | 0 | Details |
| US2231538A | Transmission control | Expired / Lapsed | 1939-06-21 | 1941-02-11 | 0 | Details |
| US2231542A | Transmission control circuit | Expired / Lapsed | 1939-06-21 | 1941-02-11 | 0 | Details |
| US2231085A | Method and apparatus for measuring force factors | Expired / Lapsed | 1939-06-03 | 1941-02-11 | 0 | Details |
| US2231634A | Variable frequency wave producing means | Expired / Lapsed | 1939-04-21 | 1941-02-11 | 0 | Details |
| US2230228A | Manufacture of magnetic cores | Expired / Lapsed | 1940-01-06 | 1941-02-04 | 0 | Details |
| US2229089A | Switching of spare channel | Expired / Lapsed | 1939-09-28 | 1941-01-21 | 0 | Details |
| US2229108A | Switching of spare repeater sections | Expired / Lapsed | 1939-09-28 | 1941-01-21 | 0 | Details |
| US2228266A | Signal translating apparatus | Expired / Lapsed | 1939-07-01 | 1941-01-14 | 0 | Details |
| US2228113A | Selective system | Expired / Lapsed | 1937-11-05 | 1941-01-07 | 0 | Details |
| US2226944A | Method of bonding dissimilar metals | Expired / Lapsed | 1938-10-27 | 1940-12-31 | 0 | Details |
| US2225653A | Compensation for variations in phase change | Expired / Lapsed | 1939-12-20 | 1940-12-24 | 0 | Details |
| US2225853A | Method of and apparatus for making grids | Expired / Lapsed | 1938-12-13 | 1940-12-24 | 0 | Details |
| US2225312A | Acoustic device | Expired / Lapsed | 1939-10-05 | 1940-12-17 | 0 | Details |
| US2225057A | Light fixture for telephone booths | Expired / Lapsed | 1939-03-31 | 1940-12-17 | 0 | Details |
| US2224677A | Signaling system | Expired / Lapsed | 1939-03-23 | 1940-12-10 | 0 | Details |
| US2223224A | Radio speed and drift indicator | Expired / Lapsed | 1939-06-24 | 1940-11-26 | 0 | Details |
| US2222688A | Vibratory frequency controlling device | Expired / Lapsed | 1939-04-19 | 1940-11-26 | 0 | Details |
| US2222417A | Wave filter | Expired / Lapsed | 1938-09-24 | 1940-11-19 | 0 | Details |
| US2222425A | Magnetic structure | Expired / Lapsed | 1938-08-20 | 1940-11-19 | 0 | Details |
| US2220883A | Circuit controller | Expired / Lapsed | 1939-07-08 | 1940-11-12 | 0 | Details |
| US2219749A | Single side band diversity radio receiving system | Expired / Lapsed | 1939-08-31 | 1940-10-29 | 0 | Details |
| US2219751A | Single side band diversity radio receiving system | Expired / Lapsed | 1939-08-23 | 1940-10-29 | 0 | Details |
| US2219888A | Extruding apparatus | Expired / Lapsed | 1938-09-15 | 1940-10-29 | 0 | Details |
| US2219021A | Frequency changing | Expired / Lapsed | 1939-06-30 | 1940-10-22 | 0 | Details |
| US2218711A | Electrical switching device | Expired / Lapsed | 1938-12-30 | 1940-10-22 | 0 | Details |
| US2217774A | Electron discharge apparatus | Expired / Lapsed | 1939-05-27 | 1940-10-15 | 0 | Details |
| US2218330A | Ventilator | Expired / Lapsed | 1939-01-10 | 1940-10-15 | 0 | Details |
| US2218225A | Piezoelectric apparatus | Expired / Lapsed | 1937-04-07 | 1940-10-15 | 0 | Details |
| US2217455A | Package | Expired / Lapsed | 1937-11-20 | 1940-10-08 | 0 | Details |
| US2216435A | Composition of matter and electrical conductor cable contai… | Expired / Lapsed | 1938-01-03 | 1940-10-01 | 0 | Details |
| US2214019A | Electronic switching device | Expired / Lapsed | 1937-10-30 | 1940-09-10 | 0 | Details |
| US2213938A | Multiplex signaling with phase discrimination | Expired / Lapsed | 1938-07-26 | 1940-09-03 | 0 | Details |
| US2213941A | Multiplex signaling by phase discrimination | Expired / Lapsed | 1938-07-26 | 1940-09-03 | 0 | Details |
| US2213398A | Vacuum tube circuit | Expired / Lapsed | 1938-07-22 | 1940-09-03 | 0 | Details |
| US2212337A | Electron discharge device circuit | Expired / Lapsed | 1939-01-27 | 1940-08-20 | 0 | Details |
| US2211020A | Telephone system | Expired / Lapsed | 1939-01-21 | 1940-08-13 | 0 | Details |
| US2210503A | Wave translation system | Expired / Lapsed | 1938-10-25 | 1940-08-06 | 0 | Details |
| US2210732A | Regulated rectifier system | Expired / Lapsed | 1938-04-21 | 1940-08-06 | 0 | Details |
| US2209157A | Educational apparatus | Expired / Lapsed | 1939-06-02 | 1940-07-23 | 0 | Details |
| US2208655A | Condenser storage equipment | Expired / Lapsed | 1938-11-19 | 1940-07-23 | 0 | Details |
| US2208665A | Amplifier circuits with controlled gain | Expired / Lapsed | 1937-09-04 | 1940-07-23 | 0 | Details |
| US2207356A | Electron discharge apparatus | Expired / Lapsed | 1938-05-04 | 1940-07-09 | 0 | Details |
| US2206080A | Transmission control and signaling system | Expired / Lapsed | 1939-04-27 | 1940-07-02 | 0 | Details |
| US2206410A | Core for forming concrete conduits | Expired / Lapsed | 1937-11-17 | 1940-07-02 | 0 | Details |
| US2204055A | Telephone system | Expired / Lapsed | 1938-11-25 | 1940-06-11 | 0 | Details |
| US2203004A | Amplifying apparatus | Expired / Lapsed | 1938-05-05 | 1940-06-04 | 0 | Details |
| US2202060A | Alarm system | Expired / Lapsed | 1936-12-12 | 1940-05-28 | 0 | Details |
| US2201344A | Mounting device | Expired / Lapsed | 1939-02-08 | 1940-05-21 | 0 | Details |
| US2201879A | Delay type piezoelectric relay | Expired / Lapsed | 1938-09-03 | 1940-05-21 | 0 | Details |
| US2199824A | Signaling system | Expired / Lapsed | 1938-04-07 | 1940-05-07 | 0 | Details |
| US2199559A | Sound picture film | Expired / Lapsed | 1938-04-07 | 1940-05-07 | 0 | Details |
| US2199219A | Terminal block | Expired / Lapsed | 1938-09-09 | 1940-04-30 | 0 | Details |
| US2199083A | Transmission of guided waves | Expired / Lapsed | 1937-09-04 | 1940-04-30 | 0 | Details |
| US2197122A | Guided wave transmission | Expired / Lapsed | 1937-06-18 | 1940-04-16 | 0 | Details |
| US2195417A | Vibrating piezoelectric relay | Expired / Lapsed | 1937-11-10 | 1940-04-02 | 0 | Details |
| US2195081A | Sound printing mechanism | Expired / Lapsed | 1938-07-01 | 1940-03-26 | 0 | Details |
| US2194298A | System for the artificial production of vocal or other soun… | Expired / Lapsed | 1937-12-23 | 1940-03-19 | 0 | Details |
| US2192961A | Signaling system | Expired / Lapsed | 1939-02-11 | 1940-03-12 | 0 | Details |
| US2192529A | Projection apparatus | Expired / Lapsed | 1938-05-10 | 1940-03-05 | 0 | Details |
| US2190668A | Diode oscillator | Expired / Lapsed | 1937-07-31 | 1940-02-20 | 0 | Details |
| US2190307A | Designation transmitter | Expired / Lapsed | 1937-08-31 | 1940-02-13 | 0 | Details |
| US2189898A | System of communication | Expired / Lapsed | 1933-08-23 | 1940-02-13 | 0 | Details |
| US2189110A | Voltage recording device | Expired / Lapsed | 1936-09-18 | 1940-02-06 | 0 | Details |
| US2188154A | Piezoelectric substance and process for producing it | Expired / Lapsed | 1938-08-04 | 1940-01-23 | 0 | Details |
| US2188159A | Gas-filled space discharge tube circuits | Expired / Lapsed | 1937-10-27 | 1940-01-23 | 0 | Details |
| US2187158A | Telegraph system | Expired / Lapsed | 1936-08-22 | 1940-01-16 | 0 | Details |
| US2186217A | Control of electric generating apparatus | Expired / Lapsed | 1938-12-30 | 1940-01-09 | 0 | Details |
| US2185693A | Multiplex signaling system | Expired / Lapsed | 1938-02-25 | 1940-01-02 | 0 | Details |
| US2185300A | Telegraphone | Expired / Lapsed | 1936-02-21 | 1940-01-02 | 0 | Details |
| US2183708A | Signaling system | Expired / Lapsed | 1938-03-03 | 1939-12-19 | 0 | Details |
| US2181265A | Signaling system | Expired / Lapsed | 1937-08-25 | 1939-11-28 | 0 | Details |
| US2181188A | Insulated cable | Expired / Lapsed | 1937-02-06 | 1939-11-28 | 0 | Details |
| US2180816A | Frequency conversion circuit | Expired / Lapsed | 1938-04-30 | 1939-11-21 | 0 | Details |
| US2180824A | Automatic call ticketing system | Expired / Lapsed | 1938-02-24 | 1939-11-21 | 0 | Details |
| US2179915A | Gain control circuits | Expired / Lapsed | 1938-09-08 | 1939-11-14 | 0 | Details |
| US2179971A | Means and method of sectionalizing coaxial cables | Expired / Lapsed | 1937-01-29 | 1939-11-14 | 0 | Details |
| US2179106A | Secrecy signaling system | Expired / Lapsed | 1937-08-11 | 1939-11-07 | 0 | Details |
| US2179261A | Method and apparatus for heating dielectric materials | Expired / Lapsed | 1937-08-11 | 1939-11-07 | 0 | Details |
| US2179098A | Electro-optical apparatus | Expired / Lapsed | 1937-08-11 | 1939-11-07 | 0 | Details |
| US2179243A | Cathode ray device | Expired / Lapsed | 1936-08-21 | 1939-11-07 | 0 | Details |
| US2178548A | Resistor | Expired / Lapsed | 1936-01-17 | 1939-11-07 | 0 | Details |
| US2178333A | Gain control circuits | Expired / Lapsed | 1938-09-08 | 1939-10-31 | 0 | Details |
| US2177260A | Apparatus for and a method of making coils | Expired / Lapsed | 1937-06-12 | 1939-10-24 | 0 | Details |
| US2173858A | Radio system | Expired / Lapsed | 1937-06-23 | 1939-09-26 | 0 | Details |
| US2174003A | Optical device | Expired / Lapsed | 1935-11-29 | 1939-09-26 | 0 | Details |
| US2173589A | Piezoelectric apparatus | Expired / Lapsed | 1933-12-14 | 1939-09-19 | 0 | Details |
| US2172847A | Assembling tool | Expired / Lapsed | 1936-06-20 | 1939-09-12 | 0 | Details |
| US2170206A | Electrical and electromechanical system employing magnetost… | Expired / Lapsed | 1937-05-08 | 1939-08-22 | 0 | Details |
| US2169732A | Method of making magnetic bodies | Expired / Lapsed | 1937-08-17 | 1939-08-15 | 0 | Details |
| US2169304A | Frequency selective system | Expired / Lapsed | 1937-06-23 | 1939-08-15 | 0 | Details |
| US2169553A | Directive radio system | Expired / Lapsed | 1936-09-11 | 1939-08-15 | 0 | Details |
| US2169396A | Signal-translating apparatus | Expired / Lapsed | 1936-05-08 | 1939-08-15 | 0 | Details |
| US2168047A | Electro-optical system | Expired / Lapsed | 1936-12-24 | 1939-08-01 | 0 | Details |
| US2167254A | Piezoelectric vibrator oscillator | Expired / Lapsed | 1938-04-23 | 1939-07-25 | 0 | Details |
| US2167525A | Cabinet | Expired / Lapsed | 1935-08-08 | 1939-07-25 | 0 | Details |
| US2165308A | Cathode ray device | Expired / Lapsed | 1937-03-31 | 1939-07-11 | 0 | Details |
| US2165510A | Electrical measuring, recording, and control system | Expired / Lapsed | 1936-03-27 | 1939-07-11 | 0 | Details |
| US2164335A | Telephone system | Expired / Lapsed | 1938-04-13 | 1939-07-04 | 0 | Details |
| US2164731A | Telephone system | Expired / Lapsed | 1937-04-07 | 1939-07-04 | 0 | Details |
| US2163403A | Stabilized oscillator | Expired / Lapsed | 1937-07-02 | 1939-06-20 | 0 | Details |
| US2163195A | Mechanical relay | Expired / Lapsed | 1936-10-08 | 1939-06-20 | 0 | Details |
| US2162268A | Signaling system | Expired / Lapsed | 1936-11-18 | 1939-06-13 | 0 | Details |
| US2161570A | Cooling system | Expired / Lapsed | 1936-04-23 | 1939-06-06 | 0 | Details |
| US2159597A | Frequency conversion circuits | Expired / Lapsed | 1938-04-30 | 1939-05-23 | 0 | Details |
| US2159595A | Frequency conversion circuits | Expired / Lapsed | 1937-07-31 | 1939-05-23 | 0 | Details |
| US2159751A | Signaling system | Expired / Lapsed | 1935-06-22 | 1939-05-23 | 0 | Details |
| US2158630A | Testing apparatus | Expired / Lapsed | 1937-04-07 | 1939-05-16 | 0 | Details |
| US2155508A | Wave guide impedance element and network | Expired / Lapsed | 1936-12-04 | 1939-04-25 | 0 | Details |
| US2155980A | Cable forming apparatus | Expired / Lapsed | 1934-05-26 | 1939-04-25 | 0 | Details |
| US2154886A | Selective signaling system | Expired / Lapsed | 1937-08-25 | 1939-04-18 | 0 | Details |
| US2155035A | Piezoelectric crystal apparatus | Expired / Lapsed | 1936-01-02 | 1939-04-18 | 0 | Details |
| US2153989A | Electrical testing apparatus | Expired / Lapsed | 1937-10-15 | 1939-04-11 | 0 | Details |
| US2153728A | Ultra high frequency signaling | Expired / Lapsed | 1936-10-07 | 1939-04-11 | 0 | Details |
| US2153638A | Amplifier | Expired / Lapsed | 1936-09-26 | 1939-04-11 | 0 | Details |
| US2151726A | Signaling device | Expired / Lapsed | 1936-09-19 | 1939-03-28 | 0 | Details |
| US2151157A | Guided electromagnetic wave transmission | Expired / Lapsed | 1936-10-31 | 1939-03-21 | 0 | Details |
| US2151118A | Termination for dielectric guides | Expired / Lapsed | 1936-02-06 | 1939-03-21 | 0 | Details |
| US2150364A | Signaling system | Expired / Lapsed | 1937-07-31 | 1939-03-14 | 0 | Details |
| US2148532A | Radio repeater | Expired / Lapsed | 1938-04-28 | 1939-02-28 | 0 | Details |
| US2148578A | Signaling system | Expired / Lapsed | 1935-07-11 | 1939-02-28 | 0 | Details |
| US2147689A | Method and apparatus for heating dielectric materials | Expired / Lapsed | 1937-08-11 | 1939-02-21 | 0 | Details |
| US2147712A | Wave filter | Expired / Lapsed | 1936-02-19 | 1939-02-21 | 0 | Details |
| US2146869A | Tension control apparatus | Expired / Lapsed | 1936-07-30 | 1939-02-14 | 0 | Details |
| US2144844A | Magnetic telegraphone | Expired / Lapsed | 1936-08-06 | 1939-01-24 | 0 | Details |
| US2143971A | Telephone system | Expired / Lapsed | 1937-03-27 | 1939-01-17 | 0 | Details |
| US2143414A | Electrical device | Expired / Lapsed | 1934-08-25 | 1939-01-10 | 0 | Details |
| US2142138A | Guided wave transmission | Expired / Lapsed | 1935-10-03 | 1939-01-03 | 0 | Details |
| US2142339A | Picture broadcasting system | Expired / Lapsed | 1934-07-07 | 1939-01-03 | 0 | Details |
| US2141281A | Wave transmission | Expired / Lapsed | 1936-07-22 | 1938-12-27 | 0 | Details |
| US2141282A | Wave transmission | Expired / Lapsed | 1936-07-22 | 1938-12-27 | 0 | Details |
| US2140138A | Impulse transmitter | Expired / Lapsed | 1937-02-18 | 1938-12-13 | 0 | Details |
| US2139232A | Transmission system | Expired / Lapsed | 1936-06-01 | 1938-12-06 | 0 | Details |
| US2138594A | Telephone system | Expired / Lapsed | 1936-01-07 | 1938-11-29 | 0 | Details |
| US2137852A | Piezoelectric oscillating and stress-measuring means | Expired / Lapsed | 1924-01-08 | 1938-11-22 | 0 | Details |
| US2137036A | Transmission system | Expired / Lapsed | 1936-10-31 | 1938-11-15 | 0 | Details |
| US2136621A | Antenna selector system | Expired / Lapsed | 1936-06-20 | 1938-11-15 | 0 | Details |
| US2136609A | Electrical device and a method of making the same | Expired / Lapsed | 1936-04-10 | 1938-11-15 | 0 | Details |
| US2137023A | Carrier communicating system | Expired / Lapsed | 1935-12-20 | 1938-11-15 | 0 | Details |
| US2133456A | Regenerative telegraph repeater | Expired / Lapsed | 1936-02-15 | 1938-10-18 | 0 | Details |
| US2132213A | Recorder of liquid level heights | Expired / Lapsed | 1936-03-12 | 1938-10-04 | 0 | Details |
| US2132225A | Timing apparatus | Expired / Lapsed | 1935-06-26 | 1938-10-04 | 0 | Details |
| US2131366A | Electric wave amplifying system | Expired / Lapsed | 1936-12-05 | 1938-09-27 | 0 | Details |
| US2131173A | Cable sheath extruding press | Expired / Lapsed | 1936-02-15 | 1938-09-27 | 0 | Details |
| US2131202A | Simplified teleprinter and system | Expired / Lapsed | 1934-11-23 | 1938-09-27 | 0 | Details |
| US2129669A | Guided wave transmission | Expired / Lapsed | 1937-05-19 | 1938-09-13 | 0 | Details |
| US2129712A | Transmission of energy effects by guided electric waves in … | Expired / Lapsed | 1933-12-09 | 1938-09-13 | 0 | Details |
| US2129711A | Guided transmission of ultra high frequency waves | Expired / Lapsed | 1933-03-16 | 1938-09-13 | 0 | Details |
| US2129008A | Condenser | Expired / Lapsed | 1936-05-20 | 1938-09-06 | 0 | Details |
| US2128412A | Cable plug | Expired / Lapsed | 1936-11-28 | 1938-08-30 | 0 | Details |
| US2127640A | Method of chromium plating | Expired / Lapsed | 1936-01-07 | 1938-08-23 | 0 | Details |
| US2122538A | Wave amplifier | Expired / Lapsed | 1935-01-22 | 1938-07-05 | 0 | Details |
| US2122468A | Apparatus control system | Expired / Lapsed | 1934-03-23 | 1938-07-05 | 0 | Details |
| US2121142A | System for the artificial production of vocal or other soun… | Expired / Lapsed | 1937-04-07 | 1938-06-21 | 0 | Details |
| US2121282A | Combined telephone and fire alarm system | Expired / Lapsed | 1936-12-12 | 1938-06-21 | 0 | Details |
| US2120971A | System and method of determining distance | Expired / Lapsed | 1935-12-21 | 1938-06-21 | 0 | Details |
| US2119607A | Radio communicating system | Expired / Lapsed | 1934-08-25 | 1938-06-07 | 0 | Details |
| US2117752A | Harmonic producer | Expired / Lapsed | 1936-05-05 | 1938-05-17 | 0 | Details |
| US2117692A | Battery box | Expired / Lapsed | 1936-01-23 | 1938-05-17 | 0 | Details |
| US2116562A | Soldering iron | Expired / Lapsed | 1935-07-02 | 1938-05-10 | 0 | Details |
| US2116996A | Variable tuned circuits | Expired / Lapsed | 1935-05-17 | 1938-05-10 | 0 | Details |
| US2116600A | Electrical transmission control | Expired / Lapsed | 1935-04-25 | 1938-05-10 | 0 | Details |
| US2116593A | Cutting or milling machine | Expired / Lapsed | 1934-04-13 | 1938-05-10 | 0 | Details |
| US2115917A | Picture transmitting system | Expired / Lapsed | 1925-03-12 | 1938-05-03 | 0 | Details |
| US2115141A | Transmission regulating system | Expired / Lapsed | 1935-02-09 | 1938-04-26 | 0 | Details |
| US2114036A | Frequency stabilization system | Expired / Lapsed | 1936-10-17 | 1938-04-12 | 0 | Details |
| US2114019A | Sound reproducing system | Expired / Lapsed | 1934-04-26 | 1938-04-12 | 0 | Details |
| US2114016A | Electrical counting system | Expired / Lapsed | 1934-01-20 | 1938-04-12 | 0 | Details |
| US2113220A | Rectifier system | Expired / Lapsed | 1936-06-01 | 1938-04-05 | 0 | Details |
| US2113253A | Therapeutic apparatus | Expired / Lapsed | 1935-12-24 | 1938-04-05 | 0 | Details |
| US2113221A | Signaling system | Expired / Lapsed | 1935-10-31 | 1938-04-05 | 0 | Details |
| US2112951A | Telephone system | Expired / Lapsed | 1934-04-28 | 1938-04-05 | 0 | Details |
| US2112542A | Electromagnet and controlling circuits therefor | Expired / Lapsed | 1936-01-17 | 1938-03-29 | 0 | Details |
| US2111632A | Relay circuit | Expired / Lapsed | 1936-12-19 | 1938-03-22 | 0 | Details |
| US2111626A | Ultrahigh frequency generator | Expired / Lapsed | 1936-05-13 | 1938-03-22 | 0 | Details |
| US2111607A | Repeatered line system | Expired / Lapsed | 1935-11-30 | 1938-03-22 | 0 | Details |
| US2111598A | Frequency indicating and controlling apparatus | Expired / Lapsed | 1935-01-26 | 1938-03-22 | 0 | Details |
| US2111023A | Noise and cross-talk reduction in telephone communication c… | Expired / Lapsed | 1935-11-05 | 1938-03-15 | 0 | Details |
| US2110260A | Telegraph system | Expired / Lapsed | 1935-12-17 | 1938-03-08 | 0 | Details |
| US2108219A | Gas tube circuits | Expired / Lapsed | 1936-07-03 | 1938-02-15 | 0 | Details |
| US2107752A | Electrical device | Expired / Lapsed | 1934-10-20 | 1938-02-08 | 0 | Details |
| US2107168A | Carrier communicating system | Expired / Lapsed | 1936-02-12 | 1938-02-01 | 0 | Details |
| US2106769A | Transmission of guided waves | Expired / Lapsed | 1935-08-23 | 1938-02-01 | 0 | Details |
| US2106768A | Filter system for high frequency electric waves | Expired / Lapsed | 1934-09-25 | 1938-02-01 | 0 | Details |
| US2105921A | Number checking system | Expired / Lapsed | 1936-03-11 | 1938-01-18 | 0 | Details |
| US2105083A | Temperature control means for extrusion apparatus | Expired / Lapsed | 1936-09-25 | 1938-01-11 | 0 | Details |
| US2104441A | Testing apparatus | Expired / Lapsed | 1936-08-19 | 1938-01-04 | 0 | Details |
| US2103481A | Signaling system and method | Expired / Lapsed | 1928-07-24 | 1937-12-28 | 0 | Details |
| US2102670A | Wave translation system | Expired / Lapsed | 1929-12-03 | 1937-12-21 | 0 | Details |
| US2102141A | Battery charging system | Expired / Lapsed | 1935-03-23 | 1937-12-14 | 0 | Details |
| US2101272A | Combined magnetostriction and piezoelectric selective device | Expired / Lapsed | 1934-07-18 | 1937-12-07 | 0 | Details |
| US2100400A | Telephone system | Expired / Lapsed | 1936-06-30 | 1937-11-30 | 0 | Details |
| US2100375A | Gain control | Expired / Lapsed | 1936-05-01 | 1937-11-30 | 0 | Details |
| US2100394A | Reception of frequency modulated waves and circuits therefor | Expired / Lapsed | 1936-01-23 | 1937-11-30 | 0 | Details |
| US2100412A | Temperature-compensated device | Expired / Lapsed | 1935-02-09 | 1937-11-30 | 0 | Details |
| US2099876A | Strand handling apparatus | Expired / Lapsed | 1934-06-09 | 1937-11-23 | 0 | Details |
| US2099889A | Television system | Expired / Lapsed | 1933-08-18 | 1937-11-23 | 0 | Details |
| US2098956A | Signaling system | Expired / Lapsed | 1936-12-02 | 1937-11-16 | 0 | Details |
| US2099065A | Distributor device | Expired / Lapsed | 1935-03-15 | 1937-11-16 | 0 | Details |
| US2099115A | Communication system | Expired / Lapsed | 1930-04-08 | 1937-11-16 | 0 | Details |
| US2098286A | Transmission control in signaling systems | Expired / Lapsed | 1936-07-31 | 1937-11-09 | 0 | Details |
| US2097501A | Electrical cable and a method of making the same | Expired / Lapsed | 1933-07-12 | 1937-11-02 | 0 | Details |
| US2096805A | Phonograph | Expired / Lapsed | 1935-09-18 | 1937-10-26 | 0 | Details |
| US2096429A | Accounting device | Expired / Lapsed | 1932-11-17 | 1937-10-19 | 0 | Details |
| US2094113A | Wave transmission | Expired / Lapsed | 1936-07-10 | 1937-09-28 | 0 | Details |
| US2094044A | Wave filter | Expired / Lapsed | 1935-07-02 | 1937-09-28 | 0 | Details |
| US2093854A | Measuring device | Expired / Lapsed | 1936-12-12 | 1937-09-21 | 0 | Details |
| US2093512A | Electrical measuring system | Expired / Lapsed | 1936-08-25 | 1937-09-21 | 0 | Details |
| US2093855A | Radio telephone monitoring system | Expired / Lapsed | 1936-05-19 | 1937-09-21 | 0 | Details |
| US2092851A | Resetting circuits for gas-filled tubes | Expired / Lapsed | 1935-06-21 | 1937-09-14 | 0 | Details |
| US2093117A | Telephone system | Expired / Lapsed | 1935-06-19 | 1937-09-14 | 0 | Details |
| US2092509A | Telephone booth | Expired / Lapsed | 1935-08-09 | 1937-09-07 | 0 | Details |
| US2092493A | Automatic stock quotation system | Expired / Lapsed | 1934-12-08 | 1937-09-07 | 0 | Details |
| US2092489A | Treatment of fibrous insulating materials | Expired / Lapsed | 1927-11-26 | 1937-09-07 | 0 | Details |
| US2091533A | Automatic measuring device | Expired / Lapsed | 1936-11-07 | 1937-08-31 | 0 | Details |
| US2090744A | Method of and apparatus for manufacturing an electrical cab… | Expired / Lapsed | 1933-10-11 | 1937-08-24 | 0 | Details |
| US2089409A | Phase correcting means and method | Expired / Lapsed | 1936-04-14 | 1937-08-10 | 0 | Details |
| US2089179A | Coaxial transmission system | Expired / Lapsed | 1936-04-07 | 1937-08-10 | 0 | Details |
| US2088750A | Answer-back device for machine switching printing telegraph… | Expired / Lapsed | 1936-01-18 | 1937-08-03 | 0 | Details |
| US2088749A | Reception of guided waves | Expired / Lapsed | 1935-10-30 | 1937-08-03 | 0 | Details |
| US2088297A | Harmonic analyzer | Expired / Lapsed | 1936-01-11 | 1937-07-27 | 0 | Details |
| US2087316A | Volume control system | Expired / Lapsed | 1935-12-11 | 1937-07-20 | 0 | Details |
| US2086683A | Gas tube circuits for measuring short-lived impulses | Expired / Lapsed | 1936-04-16 | 1937-07-13 | 0 | Details |
| US2085125A | Radio transmitter | Expired / Lapsed | 1935-06-26 | 1937-06-29 | 0 | Details |
| US2084105A | Telephone control system | Expired / Lapsed | 1936-03-11 | 1937-06-15 | 0 | Details |
| US2084135A | Amplifier circuits | Expired / Lapsed | 1935-11-21 | 1937-06-15 | 0 | Details |
| US2084149A | Apparatus for extruding matter | Expired / Lapsed | 1932-10-12 | 1937-06-15 | 0 | Details |
| US2083344A | System and method of determining distances | Expired / Lapsed | 1934-04-06 | 1937-06-08 | 0 | Details |
| US2082877A | Multiplex communication signaling system | Expired / Lapsed | 1932-10-21 | 1937-06-08 | 0 | Details |
| US2082104A | Testing system | Expired / Lapsed | 1936-01-09 | 1937-06-01 | 0 | Details |
| US2082123A | Circuit control arrangements | Expired / Lapsed | 1935-05-11 | 1937-06-01 | 0 | Details |
| US2081405A | Wave filter | Expired / Lapsed | 1935-07-27 | 1937-05-25 | 0 | Details |
| US2079690A | Method of making resistance devices | Expired / Lapsed | 1936-01-02 | 1937-05-11 | 0 | Details |
| US2077172A | Telegraph signal distortion measuring device | Expired / Lapsed | 1934-12-19 | 1937-04-13 | 0 | Details |
| US2077160A | Radio transmitter | Expired / Lapsed | 1934-07-14 | 1937-04-13 | 0 | Details |
| US2075956A | Electric wave translating system | Expired / Lapsed | 1935-05-11 | 1937-04-06 | 0 | Details |
| US2073756A | Timing mechanism | Expired / Lapsed | 1936-03-10 | 1937-03-16 | 0 | Details |
| US2073679A | Electroplating apparatus | Expired / Lapsed | 1935-02-05 | 1937-03-16 | 0 | Details |
| US2073459A | Temperature control system and method | Expired / Lapsed | 1934-02-27 | 1937-03-09 | 0 | Details |
| US2070668A | Wave transmission network | Expired / Lapsed | 1935-10-04 | 1937-02-16 | 0 | Details |
| US2070671A | Repeater testing | Expired / Lapsed | 1933-10-04 | 1937-02-16 | 0 | Details |
| US2069915A | Signaling system | Expired / Lapsed | 1935-05-01 | 1937-02-09 | 0 | Details |
| US2066522A | Protective system and method | Expired / Lapsed | 1934-12-19 | 1937-01-05 | 0 | Details |
| US2066332A | Carrier wave transmission system | Expired / Lapsed | 1934-12-14 | 1937-01-05 | 0 | Details |
| US2066333A | Wave amplification and generation | Expired / Lapsed | 1934-12-14 | 1937-01-05 | 0 | Details |
| US2064906A | Common medium multichannel exchange system | Expired / Lapsed | 1934-05-26 | 1936-12-22 | 0 | Details |
| US2064907A | Common medium multichannel exchange system | Expired / Lapsed | 1934-05-26 | 1936-12-22 | 0 | Details |
| US2064958A | Signaling system for radiotelephones | Expired / Lapsed | 1934-05-26 | 1936-12-22 | 0 | Details |
| US2063342A | Electron discharge device | Expired / Lapsed | 1934-12-08 | 1936-12-08 | 0 | Details |
| US2058263A | Cabinet | Expired / Lapsed | 1935-07-11 | 1936-10-20 | 0 | Details |
| US2058170A | Marginal control of gas-filled tubes | Expired / Lapsed | 1932-08-26 | 1936-10-20 | 0 | Details |
| US2050703A | Transmission system regulation | Expired / Lapsed | 1934-06-09 | 1936-08-11 | 0 | Details |
| US2050633A | Constant temperature device | Expired / Lapsed | 1931-06-09 | 1936-08-11 | 0 | Details |
| US2048506A | Telephone system | Expired / Lapsed | 1935-03-07 | 1936-07-21 | 0 | Details |
| US2048080A | Signaling with high frequency waves | Expired / Lapsed | 1934-02-10 | 1936-07-21 | 0 | Details |
| US2047782A | Electrical measuring system | Expired / Lapsed | 1935-05-14 | 1936-07-14 | 0 | Details |
| US2046422A | Motor generator regulator system | Expired / Lapsed | 1936-03-10 | 1936-07-07 | 0 | Details |
| US2046704A | Owen bridge | Expired / Lapsed | 1935-04-10 | 1936-07-07 | 0 | Details |
| US2045735A | Radio receiving circuits | Expired / Lapsed | 1934-05-26 | 1936-06-30 | 0 | Details |
| US2045072A | Method and means for measuring altitude of aircraft | Expired / Lapsed | 1936-01-30 | 1936-06-23 | 0 | Details |
| US2045071A | Altimeter for aircraft | Expired / Lapsed | 1930-04-29 | 1936-06-23 | 0 | Details |
| US2044470A | Impulse sender | Expired / Lapsed | 1933-04-12 | 1936-06-16 | 0 | Details |
| US2044424A | Insulation testing system | Expired / Lapsed | 1932-07-13 | 1936-06-16 | 0 | Details |
| US2042869A | Code calling system | Expired / Lapsed | 1935-01-23 | 1936-06-02 | 0 | Details |
| US2041600A | Radio system | Expired / Lapsed | 1934-04-05 | 1936-05-19 | 0 | Details |
| US2040462A | Selective signaling system | Expired / Lapsed | 1934-05-26 | 1936-05-12 | 0 | Details |
| US2040285A | Method of measuring fluid pressure | Expired / Lapsed | 1933-01-13 | 1936-05-12 | 0 | Details |
| US2039625A | Acoustic device | Expired / Lapsed | 1934-07-13 | 1936-05-05 | 0 | Details |
| US2039404A | Remote metering system | Expired / Lapsed | 1933-03-21 | 1936-05-05 | 0 | Details |
| US2038647A | Signaling system | Expired / Lapsed | 1934-09-14 | 1936-04-28 | 0 | Details |
| US2038992A | Modulating system for ultra short waves | Expired / Lapsed | 1933-12-15 | 1936-04-28 | 0 | Details |
| US2038215A | Lubricating and protective coating | Expired / Lapsed | 1934-01-10 | 1936-04-21 | 0 | Details |
| US2038202A | Carrier wave system | Expired / Lapsed | 1933-11-02 | 1936-04-21 | 0 | Details |
| US2037166A | Electrooptical system | Expired / Lapsed | 1935-05-31 | 1936-04-14 | 0 | Details |
| US2037191A | Registering device | Expired / Lapsed | 1932-09-30 | 1936-04-14 | 0 | Details |
| US2034708A | Remote control apparatus | Expired / Lapsed | 1934-04-28 | 1936-03-24 | 0 | Details |
| US2034032A | Shielded pair of wires | Expired / Lapsed | 1933-06-07 | 1936-03-17 | 0 | Details |
| US2034047A | Coaxial circuit with stranded inner conductor | Expired / Lapsed | 1933-06-07 | 1936-03-17 | 0 | Details |
| US2034260A | Accounting system | Expired / Lapsed | 1932-11-17 | 1936-03-17 | 0 | Details |
| US2033237A | Frequency control system | Expired / Lapsed | 1934-08-15 | 1936-03-10 | 0 | Details |
| US2032514A | Gas-filled tube and circuit therefor | Expired / Lapsed | 1935-06-01 | 1936-03-03 | 0 | Details |
| US2032360A | Power line carrier system | Expired / Lapsed | 1930-12-12 | 1936-03-03 | 0 | Details |
| US2031951A | Burglar alarm system | Expired / Lapsed | 1932-02-25 | 1936-02-25 | 0 | Details |
| US2030412A | Telephone exchange system | Expired / Lapsed | 1934-10-24 | 1936-02-11 | 0 | Details |
| US2030443A | Solid rectifying element | Expired / Lapsed | 1934-07-19 | 1936-02-11 | 0 | Details |
| US2030179A | Electrical circuit arrangement | Expired / Lapsed | 1933-08-18 | 1936-02-11 | 0 | Details |
| US2028212A | Radio transmitting system | Expired / Lapsed | 1933-12-22 | 1936-01-21 | 0 | Details |
| US2025407A | Electrical recorder | Expired / Lapsed | 1933-04-21 | 1935-12-24 | 0 | Details |
| US2024609A | Sound picture system | Expired / Lapsed | 1933-11-14 | 1935-12-17 | 0 | Details |
| US2022972A | Variable gain amplifier | Expired / Lapsed | 1934-08-21 | 1935-12-03 | 0 | Details |
| US2022969A | Electrical wave production | Expired / Lapsed | 1934-07-07 | 1935-12-03 | 0 | Details |
| US2023011A | Telephone system | Expired / Lapsed | 1934-05-22 | 1935-12-03 | 0 | Details |
| US2022991A | Alarm transmitting system | Expired / Lapsed | 1933-12-01 | 1935-12-03 | 0 | Details |
| US2022790A | Frequency indicating system | Expired / Lapsed | 1933-08-24 | 1935-12-03 | 0 | Details |
| US2021920A | Control circuits | Expired / Lapsed | 1935-01-15 | 1935-11-26 | 0 | Details |
| US2020409A | Band separation system | Expired / Lapsed | 1933-08-15 | 1935-11-12 | 0 | Details |
| US2019594A | Signal transmission system | Expired / Lapsed | 1933-07-21 | 1935-11-05 | 0 | Details |
| US2018384A | Gauge | Expired / Lapsed | 1933-09-14 | 1935-10-22 | 0 | Details |
| US2018464A | Voice operated transmission circuit | Expired / Lapsed | 1930-06-07 | 1935-10-22 | 0 | Details |
| US2016420A | Gauge | Expired / Lapsed | 1933-11-02 | 1935-10-08 | 0 | Details |
| US2014524A | Article | Expired / Lapsed | 1933-04-28 | 1935-09-17 | 0 | Details |
| US2012995A | Stereoscopic motion picture | Expired / Lapsed | 1929-02-09 | 1935-09-03 | 0 | Details |
| US2011932A | Projection of motion pictures | Expired / Lapsed | 1932-01-23 | 1935-08-20 | 0 | Details |
| US2009438A | Carrier wave transmission system | Expired / Lapsed | 1931-07-31 | 1935-07-30 | 0 | Details |
| US2008857A | Mechanical impedance meter | Expired / Lapsed | 1933-04-04 | 1935-07-23 | 0 | Details |
| US2008874A | Photo-electric tube | Expired / Lapsed | 1929-04-06 | 1935-07-23 | 0 | Details |
| US2008288A | Wire wound electrical device | Expired / Lapsed | 1934-01-31 | 1935-07-16 | 0 | Details |
| US2007172A | Wave translation system | Expired / Lapsed | 1933-03-29 | 1935-07-09 | 0 | Details |
| US2006354A | Telephone system | Expired / Lapsed | 1934-06-20 | 1935-07-02 | 0 | Details |
| US2006698A | Electrical measuring system | Expired / Lapsed | 1934-05-26 | 1935-07-02 | 0 | Details |
| US2005588A | Stylus feed mechanism for phonographs | Expired / Lapsed | 1931-08-28 | 1935-06-18 | 0 | Details |
| US2004248A | Time announcing system | Expired / Lapsed | 1933-12-22 | 1935-06-11 | 0 | Details |
| US2003428A | Volume control for transmission circuits | Expired / Lapsed | 1932-09-20 | 1935-06-04 | 0 | Details |
| US2003282A | Wave translation system | Expired / Lapsed | 1929-12-03 | 1935-06-04 | 0 | Details |
| US2000990A | Electron discharge device | Expired / Lapsed | 1933-10-27 | 1935-05-14 | 0 | Details |
| US2000130A | Wide band transmission system | Expired / Lapsed | 1932-12-16 | 1935-05-07 | 0 | Details |
| US1998827A | Composite articles and their method of manufacture | Expired / Lapsed | 1932-03-10 | 1935-04-23 | 0 | Details |
| US1998119A | Frequency changer and circuits therefor | Expired / Lapsed | 1932-08-19 | 1935-04-16 | 0 | Details |
| US1998072A | Signal and contact device | Expired / Lapsed | 1930-06-07 | 1935-04-16 | 0 | Details |
| US1994624A | Control system | Expired / Lapsed | 1933-01-07 | 1935-03-19 | 0 | Details |
| US1992268A | Acoustic device | Expired / Lapsed | 1933-04-11 | 1935-02-26 | 0 | Details |
| US1992271A | Automatic stock quotation system | Expired / Lapsed | 1931-09-17 | 1935-02-26 | 0 | Details |
| US1988609A | Synchronizing system | Expired / Lapsed | 1931-07-21 | 1935-01-22 | 0 | Details |
| US1984036A | Electrical insulating device having a terminal thereon and … | Expired / Lapsed | 1932-10-12 | 1934-12-11 | 0 | Details |
| US1981999A | Optical telephone system | Expired / Lapsed | 1932-08-20 | 1934-11-27 | 0 | Details |
| US1981689A | Program distributing system | Expired / Lapsed | 1933-08-16 | 1934-11-20 | 0 | Details |
| US1981652A | Method of coating electrodes | Expired / Lapsed | 1931-04-28 | 1934-11-20 | 0 | Details |
| US1979414A | Differential mechanism | Expired / Lapsed | 1933-11-22 | 1934-11-06 | 0 | Details |
| US1977703A | Method of and apparatus for electrical testing | Expired / Lapsed | 1932-01-07 | 1934-10-23 | 0 | Details |
| US1977677A | Electrical connecter | Expired / Lapsed | 1930-09-27 | 1934-10-23 | 0 | Details |
| US1977697A | Control apparatus | Expired / Lapsed | 1929-10-23 | 1934-10-23 | 0 | Details |
| US1976481A | Wave analysis | Expired / Lapsed | 1931-08-20 | 1934-10-09 | 0 | Details |
| US1976570A | Constant frequency oscillator | Expired / Lapsed | 1930-08-28 | 1934-10-09 | 0 | Details |
| US1972985A | Electric switching device | Expired / Lapsed | 1930-09-23 | 1934-09-11 | 0 | Details |
| US1971686A | Telegraph signal transmitting circuits | Expired / Lapsed | 1932-02-03 | 1934-08-28 | 0 | Details |
| US1969488A | Circuit controller | Expired / Lapsed | 1930-09-23 | 1934-08-07 | 0 | Details |
| US1968420A | Telephone system | Expired / Lapsed | 1933-02-16 | 1934-07-31 | 0 | Details |
| US1967250A | Wave filter | Expired / Lapsed | 1933-01-26 | 1934-07-24 | 0 | Details |
| US1966491A | Antenna system | Expired / Lapsed | 1930-12-01 | 1934-07-17 | 0 | Details |
| US1965439A | Regulated rectifier circuit | Expired / Lapsed | 1933-02-03 | 1934-07-03 | 0 | Details |
| US1959429A | Crystal filter | Expired / Lapsed | 1931-04-01 | 1934-05-22 | 0 | Details |
| US1960011A | Apparatus for making stereoscopic parallax panoramagrams | Expired / Lapsed | 1931-02-26 | 1934-05-22 | 0 | Details |
| US1958620A | Piezo-electric crystals having low temperature coefficients… | Expired / Lapsed | 1929-04-02 | 1934-05-15 | 0 | Details |
| US1957519A | Multiple radio receiving system | Expired / Lapsed | 1931-12-18 | 1934-05-08 | 0 | Details |
| US1957565A | Alarm system | Expired / Lapsed | 1931-10-31 | 1934-05-08 | 0 | Details |
| US1957538A | Electrical network | Expired / Lapsed | 1931-06-13 | 1934-05-08 | 0 | Details |
| US1957487A | Multicore cable with thermoplastic insulation | Expired / Lapsed | 1930-11-12 | 1934-05-08 | 0 | Details |
| US1956670A | Selective signaling system | Expired / Lapsed | 1932-11-01 | 1934-05-01 | 0 | Details |
| US1955788A | Transmission network | Expired / Lapsed | 1931-11-28 | 1934-04-24 | 0 | Details |
| US1954995A | Process for metal-coating phonograph records | Expired / Lapsed | 1931-05-29 | 1934-04-17 | 0 | Details |
| US1954950A | Apparatus for metallically coating phonograph records | Expired / Lapsed | 1931-05-29 | 1934-04-17 | 0 | Details |
| US1953474A | Telephone exchange system | Expired / Lapsed | 1930-05-07 | 1934-04-03 | 0 | Details |
| US1951457A | Universal framework | Expired / Lapsed | 1932-03-02 | 1934-03-20 | 0 | Details |
| US1951461A | Apparatus for measuring electrical quantities | Expired / Lapsed | 1931-12-05 | 1934-03-20 | 0 | Details |
| US1948973A | Wave transmission with narrowed band | Expired / Lapsed | 1932-06-10 | 1934-02-27 | 0 | Details |
| US1944238A | Telegraphone | Expired / Lapsed | 1931-04-15 | 1934-01-23 | 0 | Details |
| US1943475A | System for selective calling of telegraph stations | Expired / Lapsed | 1932-06-14 | 1934-01-16 | 0 | Details |
| US1940088A | Sound picture record container | Expired / Lapsed | 1929-10-31 | 1933-12-19 | 0 | Details |
| US1938742A | Gas-filled discharge tube | Expired / Lapsed | 1932-11-16 | 1933-12-12 | 0 | Details |
| US1938684A | Testing apparatus | Expired / Lapsed | 1931-09-25 | 1933-12-12 | 0 | Details |
| US1936683A | Frequency measurement | Expired / Lapsed | 1931-09-04 | 1933-11-28 | 0 | Details |
| US1934377A | Conveyer system | Expired / Lapsed | 1932-03-10 | 1933-11-07 | 0 | Details |
| US1933650A | Signaling system | Expired / Lapsed | 1927-04-06 | 1933-11-07 | 0 | Details |
| US1933274A | Testing device | Expired / Lapsed | 1932-03-30 | 1933-10-31 | 0 | Details |
| US1931866A | Gain control circuits | Expired / Lapsed | 1932-06-16 | 1933-10-24 | 0 | Details |
| US1930609A | Signaling system | Expired / Lapsed | 1932-04-21 | 1933-10-17 | 0 | Details |
| US1930631A | Signaling system | Expired / Lapsed | 1932-03-18 | 1933-10-17 | 0 | Details |
| US1930905A | Piezo-electric apparatus | Expired / Lapsed | 1931-10-31 | 1933-10-17 | 0 | Details |
| US1931054A | Measuring apparatus | Expired / Lapsed | 1930-10-09 | 1933-10-17 | 0 | Details |
| US1930269A | Inductance device | Expired / Lapsed | 1931-01-30 | 1933-10-10 | 0 | Details |
| US1928610A | High frequency signaling system | Expired / Lapsed | 1925-12-24 | 1933-10-03 | 0 | Details |
| US1927400A | Method of applying and vulcanizing an insulating compound | Expired / Lapsed | 1932-10-29 | 1933-09-19 | 0 | Details |
| US1926169A | Phase and frequency control | Expired / Lapsed | 1931-03-11 | 1933-09-12 | 0 | Details |
| US1922059A | Radio receiving system | Expired / Lapsed | 1930-11-01 | 1933-08-15 | 0 | Details |
| US1922115A | Antenna array | Expired / Lapsed | 1930-04-12 | 1933-08-15 | 0 | Details |
| US1921022A | Submarine cable signaling system | Expired / Lapsed | 1931-07-25 | 1933-08-08 | 0 | Details |
| US1919803A | Measuring and indicating system | Expired / Lapsed | 1931-03-17 | 1933-07-25 | 0 | Details |
| US1918252A | High speed telegraphy | Expired / Lapsed | 1931-05-25 | 1933-07-18 | 0 | Details |
| US1919046A | Selective calling circuits | Expired / Lapsed | 1931-03-05 | 1933-07-18 | 0 | Details |
| US1917418A | Electric delay circuits | Expired / Lapsed | 1931-06-18 | 1933-07-11 | 0 | Details |
| US1917009A | Electrical connecter | Expired / Lapsed | 1931-03-17 | 1933-07-04 | 0 | Details |
| US1915358A | Electrodynamic device | Expired / Lapsed | 1930-04-11 | 1933-06-27 | 0 | Details |
| US1915368A | Oscillator | Expired / Lapsed | 1928-08-08 | 1933-06-27 | 0 | Details |
| US1913428A | Radio receiver circuit | Expired / Lapsed | 1929-03-14 | 1933-06-13 | 0 | Details |
| US1910957A | Reactive element having stable temperature-reactance charac… | Expired / Lapsed | 1932-01-13 | 1933-05-23 | 0 | Details |
| US1910977A | Wave transmission system | Expired / Lapsed | 1931-08-14 | 1933-05-23 | 0 | Details |
| US1910254A | Sound recording | Expired / Lapsed | 1929-10-30 | 1933-05-23 | 0 | Details |
| US1907109A | Radio signaling system | Expired / Lapsed | 1930-12-12 | 1933-05-02 | 0 | Details |
| US1905359A | Channel selection | Expired / Lapsed | 1931-11-14 | 1933-04-25 | 0 | Details |
| US1904261A | Indirectly heated cathode | Expired / Lapsed | 1931-03-16 | 1933-04-18 | 0 | Details |
| US1901921A | Electrical meter | Expired / Lapsed | 1930-05-24 | 1933-03-21 | 0 | Details |
| US1901400A | Harmonic analyzer | Expired / Lapsed | 1931-08-27 | 1933-03-14 | 0 | Details |
| US1898118A | Signaling system | Expired / Lapsed | 1931-11-10 | 1933-02-21 | 0 | Details |
| US1898921A | Remote control system | Expired / Lapsed | 1930-09-24 | 1933-02-21 | 0 | Details |
| US1897040A | Inductive device | Expired / Lapsed | 1932-03-08 | 1933-02-14 | 0 | Details |
| US1896480A | Balanced inductance device | Expired / Lapsed | 1931-06-29 | 1933-02-07 | 0 | Details |
| US1896513A | Piezo-electric crystal | Expired / Lapsed | 1930-10-08 | 1933-02-07 | 0 | Details |
| US1895774A | Signal shaping circuit | Expired / Lapsed | 1932-01-12 | 1933-01-31 | 0 | Details |
| US1895542A | Pilot channel indicating system | Expired / Lapsed | 1928-09-25 | 1933-01-31 | 0 | Details |
| US1895498A | Electric regulator | Expired / Lapsed | 1919-06-11 | 1933-01-31 | 0 | Details |
| US1891299A | Radio telephone system | Expired / Lapsed | 1929-09-20 | 1932-12-20 | 0 | Details |
| US1890543A | Current-suppressor | Expired / Lapsed | 1930-04-17 | 1932-12-13 | 0 | Details |
| US1883291A | Projection of stereoscopic pictures | Expired / Lapsed | 1930-10-29 | 1932-10-18 | 0 | Details |
| US1882849A | Frequency control system | Expired / Lapsed | 1929-07-31 | 1932-10-18 | 0 | Details |
| US1883116A | Device for determining the condition of alpha gas | Expired / Lapsed | 1929-02-16 | 1932-10-18 | 0 | Details |
| US1881711A | Magnetic structure | Expired / Lapsed | 1931-08-14 | 1932-10-11 | 0 | Details |
| US1881642A | Transmission control circuits | Expired / Lapsed | 1931-07-15 | 1932-10-11 | 0 | Details |
| US1881483A | Radio transmission systems | Expired / Lapsed | 1930-06-10 | 1932-10-11 | 0 | Details |
| US1880805A | Inductive device | Expired / Lapsed | 1932-03-16 | 1932-10-04 | 0 | Details |
| US1880806A | Heat treating furnace | Expired / Lapsed | 1931-04-10 | 1932-10-04 | 0 | Details |
| US1878147A | Electrooptical transmission | Expired / Lapsed | 1927-09-10 | 1932-09-20 | 0 | Details |
| US1875157A | Compression and expansion of range of energy level | Expired / Lapsed | 1929-06-29 | 1932-08-30 | 0 | Details |
| US1871944A | Transmission measuring system | Expired / Lapsed | 1932-01-14 | 1932-08-16 | 0 | Details |
| US1870352A | Telegraph system | Expired / Lapsed | 1930-08-13 | 1932-08-09 | 0 | Details |
| US1869181A | Electric test connecter | Expired / Lapsed | 1929-09-06 | 1932-07-26 | 0 | Details |
| US1869160A | Piezo-electric resonator | Expired / Lapsed | 1928-05-11 | 1932-07-26 | 0 | Details |
| US1866631A | Magneto-optical device | Expired / Lapsed | 1928-06-28 | 1932-07-12 | 0 | Details |
| US1866097A | Electrical heating device | Expired / Lapsed | 1929-05-14 | 1932-07-05 | 0 | Details |
| US1863307A | Telephone exchange system | Expired / Lapsed | 1931-01-27 | 1932-06-14 | 0 | Details |
| US1862556A | Tool | Expired / Lapsed | 1930-08-09 | 1932-06-14 | 0 | Details |
| US1863309A | Motion picture projector | Expired / Lapsed | 1930-04-05 | 1932-06-14 | 0 | Details |
| US1862595A | Voltage regulator | Expired / Lapsed | 1930-03-17 | 1932-06-14 | 0 | Details |
| US1862571A | Terminal strip | Expired / Lapsed | 1929-04-13 | 1932-06-14 | 0 | Details |
| US1859423A | Sound recording | Expired / Lapsed | 1929-05-07 | 1932-05-24 | 0 | Details |
| US1858364A | Multiple slide wire potentiometer | Expired / Lapsed | 1929-05-14 | 1932-05-17 | 0 | Details |
| US1858339A | Piezo electric oscillator | Expired / Lapsed | 1926-06-24 | 1932-05-17 | 0 | Details |
| US1856707A | Frequency measuring circuits | Expired / Lapsed | 1928-03-28 | 1932-05-03 | 0 | Details |
| US1855855A | Molding die | Expired / Lapsed | 1929-07-29 | 1932-04-26 | 0 | Details |
| US1854828A | Transmission system | Expired / Lapsed | 1930-04-12 | 1932-04-19 | 0 | Details |
| US1852045A | Signaling arrangement for telephone lines | Expired / Lapsed | 1931-04-10 | 1932-04-05 | 0 | Details |
| US1847079A | Wave modulation and application thereof | Expired / Lapsed | 1926-12-21 | 1932-03-01 | 0 | Details |
| US1844110A | Determination of telephone quality | Expired / Lapsed | 1930-04-17 | 1932-02-09 | 0 | Details |
| US1844886A | Means for measuring time of propagation of wave fronts over… | Expired / Lapsed | 1927-12-02 | 1932-02-09 | 0 | Details |
| US1841084A | Telephone system | Expired / Lapsed | 1930-04-19 | 1932-01-12 | 0 | Details |
| US1839490A | Apparatus for distributing parts | Expired / Lapsed | 1928-12-04 | 1932-01-05 | 0 | Details |
| US1839290A | Direction finder for radiowaves | Expired / Lapsed | 1928-04-25 | 1932-01-05 | 0 | Details |
| US1840112A | Artificial larynx | Expired / Lapsed | 1927-12-17 | 1932-01-05 | 0 | Details |
| US1837337A | Means for producing current of reduced frequency | Expired / Lapsed | 1928-06-02 | 1931-12-22 | 0 | Details |
| US1837364A | Signaling apparatus | Expired / Lapsed | 1925-08-20 | 1931-12-22 | 0 | Details |
| US1836594A | Radio signaling system | Expired / Lapsed | 1925-10-16 | 1931-12-15 | 0 | Details |
| US1835031A | Concentric conducting system | Expired / Lapsed | 1929-05-23 | 1931-12-08 | 0 | Details |
| US1832292A | Electrical circuits | Expired / Lapsed | 1928-08-28 | 1931-11-17 | 0 | Details |
| US1829836A | Signaling system | Expired / Lapsed | 1928-03-05 | 1931-11-03 | 0 | Details |
| US1828454A | Transmission network | Expired / Lapsed | 1930-07-03 | 1931-10-20 | 0 | Details |
| US1828507A | Circuit controlling device | Expired / Lapsed | 1927-06-14 | 1931-10-20 | 0 | Details |
| US1827297A | Method of joining wires by means of sleeves | Expired / Lapsed | 1930-01-03 | 1931-10-13 | 0 | Details |
| US1827187A | Recording apparatus | Expired / Lapsed | 1927-11-30 | 1931-10-13 | 0 | Details |
| US1825723A | Telephone system | Expired / Lapsed | 1929-04-03 | 1931-10-06 | 0 | Details |
| US1824801A | Electrical potentiometer | Expired / Lapsed | 1926-07-08 | 1931-09-29 | 0 | Details |
| US1824827A | Radio signaling system | Expired / Lapsed | 1925-09-25 | 1931-09-29 | 0 | Details |
| US1823354A | High speed submarine cable telegraph system | Expired / Lapsed | 1929-08-19 | 1931-09-15 | 0 | Details |
| US1820088A | Recording apparatus | Expired / Lapsed | 1927-09-07 | 1931-08-25 | 0 | Details |
| US1819083A | Phonograph reproducer | Expired / Lapsed | 1929-05-14 | 1931-08-18 | 0 | Details |
| US1819612A | Electrical connecting cord and method of producing it | Expired / Lapsed | 1927-11-26 | 1931-08-18 | 0 | Details |
| US1819054A | Carrier signaling system | Expired / Lapsed | 1927-05-24 | 1931-08-18 | 0 | Details |
| US1818018A | Control circuit | Expired / Lapsed | 1930-07-11 | 1931-08-11 | 0 | Details |
| US1816887A | Automatic article selecting and distributing system | Expired / Lapsed | 1929-06-28 | 1931-08-04 | 0 | Details |
| US1816905A | Communication system | Expired / Lapsed | 1929-02-21 | 1931-08-04 | 0 | Details |
| US1815996A | Telegraph reading machine | Expired / Lapsed | 1929-06-29 | 1931-07-28 | 0 | Details |
| US1815986A | Telegraph reading machine | Expired / Lapsed | 1929-06-29 | 1931-07-28 | 0 | Details |
| US1815212A | Terminal connecter | Expired / Lapsed | 1930-09-18 | 1931-07-21 | 0 | Details |
| US1815717A | Apparatus for measuring variations in thickness of metallic… | Expired / Lapsed | 1926-01-12 | 1931-07-21 | 0 | Details |
| US1813913A | Rotary distributor | Expired / Lapsed | 1928-12-07 | 1931-07-14 | 0 | Details |
| US1814158A | Signaling system | Expired / Lapsed | 1926-04-22 | 1931-07-14 | 0 | Details |
| US1813197A | Cable forming apparatus | Expired / Lapsed | 1929-08-30 | 1931-07-07 | 0 | Details |
| US1812977A | Oscillation generator | Expired / Lapsed | 1925-11-25 | 1931-07-07 | 0 | Details |
| US1811839A | Sound transmission | Expired / Lapsed | 1929-06-14 | 1931-06-30 | 0 | Details |
| US1811858A | Control system for transmission of signals | Expired / Lapsed | 1929-04-30 | 1931-06-30 | 0 | Details |
| US1812828A | Switch or commutating means | Expired / Lapsed | 1928-10-18 | 1931-06-30 | 0 | Details |
| US1811102A | Signal transmission by guided and unguided waves | Expired / Lapsed | 1924-09-10 | 1931-06-23 | 0 | Details |
| US1809925A | Variable resistance device | Expired / Lapsed | 1929-05-14 | 1931-06-16 | 0 | Details |
| US1805591A | Signaling system | Expired / Lapsed | 1926-12-18 | 1931-05-19 | 0 | Details |
| US1804526A | Radio receiving circuit | Expired / Lapsed | 1926-09-01 | 1931-05-12 | 0 | Details |
| US1801342A | Electrical network | Expired / Lapsed | 1927-07-02 | 1931-04-21 | 0 | Details |
| US1799627A | Signal-interpolating system | Expired / Lapsed | 1929-02-28 | 1931-04-07 | 0 | Details |
| US1799795A | Sound recording and reproducing | Expired / Lapsed | 1928-05-05 | 1931-04-07 | 0 | Details |
| US1797317A | Binaural phase-discrimination radio system | Expired / Lapsed | 1928-12-20 | 1931-03-24 | 0 | Details |
| US1795647A | Method and apparatus for measuring acoustical impedances | Expired / Lapsed | 1929-02-19 | 1931-03-10 | 0 | Details |
| US1794393A | Transmission-measuring apparatus | Expired / Lapsed | 1929-10-22 | 1931-03-03 | 0 | Details |
| US1794418A | Radio receiving circuit | Expired / Lapsed | 1928-09-20 | 1931-03-03 | 0 | Details |
| US1791587A | Printing-telegraph system | Expired / Lapsed | 1928-12-01 | 1931-02-10 | 0 | Details |
| US1788533A | Frequency-control system | Expired / Lapsed | 1927-03-28 | 1931-01-13 | 0 | Details |
| US1788519A | Mechanical transmission system | Expired / Lapsed | 1926-05-26 | 1931-01-13 | 0 | Details |
| US1784867A | Signaling system | Expired / Lapsed | 1927-06-13 | 1930-12-16 | 0 | Details |
| US1784176A | Equalization for carrier systems | Expired / Lapsed | 1929-07-02 | 1930-12-09 | 0 | Details |
| US1782438A | Clamping device | Expired / Lapsed | 1929-04-30 | 1930-11-25 | 0 | Details |
| US1781363A | Electrical testing system | Expired / Lapsed | 1927-07-08 | 1930-11-11 | 0 | Details |
| US1778761A | Remote control system | Expired / Lapsed | 1924-03-03 | 1930-10-21 | 0 | Details |
| US1778378A | Telephone system | Expired / Lapsed | 1929-04-27 | 1930-10-14 | 0 | Details |
| US1778085A | Distortionless amplifying system | Expired / Lapsed | 1926-11-24 | 1930-10-14 | 0 | Details |
| US1777118A | Acoustic device | Expired / Lapsed | 1928-10-04 | 1930-09-30 | 0 | Details |
| US1776822A | Automatic volume-control system | Expired / Lapsed | 1927-05-21 | 1930-09-30 | 0 | Details |
| US1775775A | Method of and means for wave retardation | Expired / Lapsed | 1926-08-07 | 1930-09-16 | 0 | Details |
| US1775241A | Electrooptical system | Expired / Lapsed | 1929-05-25 | 1930-09-09 | 0 | Details |
| US1773772A | Harmonic suppressor | Expired / Lapsed | 1926-12-30 | 1930-08-26 | 0 | Details |
| US1773116A | Single-side-band system | Expired / Lapsed | 1928-01-24 | 1930-08-19 | 0 | Details |
| US1772506A | Wave filter | Expired / Lapsed | 1923-04-02 | 1930-08-12 | 0 | Details |
| US1772167A | Signaling system | Expired / Lapsed | 1926-12-31 | 1930-08-05 | 0 | Details |
| US1771446A | Regenerative telegraph repeater | Expired / Lapsed | 1928-06-09 | 1930-07-29 | 0 | Details |
| US1771445A | Regenerative telegraph repeater | Expired / Lapsed | 1928-06-09 | 1930-07-29 | 0 | Details |
| US1770969A | Method of and apparatus for sheathing cores | Expired / Lapsed | 1928-12-19 | 1930-07-22 | 0 | Details |
| US1771148A | Central energy wave signaling system | Expired / Lapsed | 1923-06-29 | 1930-07-22 | 0 | Details |
| US1769920A | Electrooptical transmission system | Expired / Lapsed | 1929-04-30 | 1930-07-08 | 0 | Details |
| US1765413A | Vibratory element and method of producing the same | Expired / Lapsed | 1928-12-31 | 1930-06-24 | 0 | Details |
| US1765607A | Amplifying device | Expired / Lapsed | 1928-04-26 | 1930-06-24 | 0 | Details |
| US1768262A | Phase measuring system and method | Expired / Lapsed | 1928-02-07 | 1930-06-24 | 0 | Details |
| US1765585A | Set for measuring operating time of relays | Expired / Lapsed | 1926-09-21 | 1930-06-24 | 0 | Details |
| US1763909A | Speed regulator | Expired / Lapsed | 1927-06-23 | 1930-06-17 | 0 | Details |
| US1764665A | Power-driven apparatus | Expired / Lapsed | 1926-11-26 | 1930-06-17 | 0 | Details |
| US1762984A | Secret-communicating system | Expired / Lapsed | 1928-10-08 | 1930-06-10 | 0 | Details |
| US1762725A | Method of and means for indicating synchronism | Expired / Lapsed | 1928-03-24 | 1930-06-10 | 0 | Details |
| US1762969A | High-frequency attenuating network | Expired / Lapsed | 1925-04-10 | 1930-06-10 | 0 | Details |
| US1759952A | Electrical transmission system | Expired / Lapsed | 1926-03-01 | 1930-05-27 | 0 | Details |
| US1756097A | Electrical delay-circuit arrangement | Expired / Lapsed | 1928-09-24 | 1930-04-29 | 0 | Details |
| US1755244A | Device for measuring level differences | Expired / Lapsed | 1928-12-20 | 1930-04-22 | 0 | Details |
| US1754240A | Composite telephone and telegraph system | Expired / Lapsed | 1926-09-08 | 1930-04-15 | 0 | Details |
| US1753444A | Signaling system | Expired / Lapsed | 1926-10-08 | 1930-04-08 | 0 | Details |
| US1752303A | Interference neutralizer for alternating-current telegraph … | Expired / Lapsed | 1930-01-24 | 1930-04-01 | 0 | Details |
| US1752346A | Interference neutralizer for alternating-current telegraph … | Expired / Lapsed | 1929-02-01 | 1930-04-01 | 0 | Details |
| US1751516A | Common-frequency broadcasting system | Expired / Lapsed | 1927-08-08 | 1930-03-25 | 0 | Details |
| US1750668A | Determining movement and position of moving objects | Expired / Lapsed | 1927-12-08 | 1930-03-18 | 0 | Details |
| US1746829A | Radio signaling system | Expired / Lapsed | 1925-07-14 | 1930-02-11 | 0 | Details |
| US1745419A | Apparatus for testing open-wire joints | Expired / Lapsed | 1927-09-28 | 1930-02-04 | 0 | Details |
| US1744835A | Constant-frequency oscillator | Expired / Lapsed | 1925-09-22 | 1930-01-28 | 0 | Details |
| US1744044A | Single-side-band carrier system | Expired / Lapsed | 1926-09-20 | 1930-01-21 | 0 | Details |
| US1743386A | Electrical testing apparatus | Expired / Lapsed | 1927-07-12 | 1930-01-14 | 0 | Details |
| US1743414A | Method and apparatus for determining the properties of acou… | Expired / Lapsed | 1926-07-13 | 1930-01-14 | 0 | Details |
| US1743711A | Supervisory system | Expired / Lapsed | 1925-11-21 | 1930-01-14 | 0 | Details |
| US1742902A | Multichannel radio communication system | Expired / Lapsed | 1925-02-14 | 1930-01-07 | 0 | Details |
| US1741375A | Current-equalizing device | Expired / Lapsed | 1928-09-24 | 1929-12-31 | 0 | Details |
| US1739520A | Radioreceiving circuits | Expired / Lapsed | 1926-12-04 | 1929-12-17 | 0 | Details |
| US1738522A | Electromagnetic wave signaling system | Expired / Lapsed | 1919-09-30 | 1929-12-10 | 0 | Details |
| US1738299A | Intermittently-operated signaling device | Expired / Lapsed | 1926-11-30 | 1929-12-03 | 0 | Details |
| US1734745A | Apparatus for removing insulation | Expired / Lapsed | 1926-06-30 | 1929-11-05 | 0 | Details |
| US1734038A | Electrical transmission of energy | Expired / Lapsed | 1918-08-12 | 1929-11-05 | 0 | Details |
| US1733614A | Subharmonic frequency producer | Expired / Lapsed | 1927-08-20 | 1929-10-29 | 0 | Details |
| US1731264A | Apparatus for controlling the output of alternating-current… | Expired / Lapsed | 1928-03-01 | 1929-10-15 | 0 | Details |
| US1728986A | Picture-transmission system | Expired / Lapsed | 1926-07-08 | 1929-09-24 | 0 | Details |
| US1725022A | Alarm | Expired / Lapsed | 1927-09-10 | 1929-08-20 | 0 | Details |
| US1724973A | Testing device | Expired / Lapsed | 1925-07-24 | 1929-08-20 | 0 | Details |
| US1722751A | Optical inspection system | Expired / Lapsed | 1927-11-19 | 1929-07-30 | 0 | Details |
| US1722121A | Electron-discharge device | Expired / Lapsed | 1925-06-25 | 1929-07-23 | 0 | Details |
| US1720738A | Signaling system | Expired / Lapsed | 1926-12-16 | 1929-07-16 | 0 | Details |
| US1719474A | Current-controlling device | Expired / Lapsed | 1928-04-18 | 1929-07-02 | 0 | Details |
| US1719492A | Regulator system | Expired / Lapsed | 1928-01-25 | 1929-07-02 | 0 | Details |
| US1719456A | System of space discharge devices | Expired / Lapsed | 1924-02-25 | 1929-07-02 | 0 | Details |
| US1717400A | Phase-shifting network | Expired / Lapsed | 1926-08-25 | 1929-06-18 | 0 | Details |
| US1717070A | Rectifying system | Expired / Lapsed | 1921-11-01 | 1929-06-11 | 0 | Details |
| US1715415A | Volume-control system | Expired / Lapsed | 1925-12-19 | 1929-06-04 | 0 | Details |
| US1712993A | Signaling system | Expired / Lapsed | 1916-08-14 | 1929-05-14 | 0 | Details |
| US1711101A | Means for indicating frequency changes | Expired / Lapsed | 1923-08-21 | 1929-04-30 | 0 | Details |
| US1709067A | Indicating system | Expired / Lapsed | 1924-10-22 | 1929-04-16 | 0 | Details |
| US1709076A | Multiplex signaling system | Expired / Lapsed | 1924-09-24 | 1929-04-16 | 0 | Details |
| US1707260A | Recording and reproducing of sound waves | Expired / Lapsed | 1927-11-10 | 1929-04-02 | 0 | Details |
| US1707544A | Electrodynamic device | Expired / Lapsed | 1926-08-04 | 1929-04-02 | 0 | Details |
| US1706538A | Testing television and like system | Expired / Lapsed | 1927-06-22 | 1929-03-26 | 0 | Details |
| US1705903A | Power line signaling | Expired / Lapsed | 1927-02-09 | 1929-03-19 | 0 | Details |
| US1705993A | Voltage-limiting device | Expired / Lapsed | 1925-11-25 | 1929-03-19 | 0 | Details |
| US1702568A | Constant frequency wave source | Expired / Lapsed | 1927-11-26 | 1929-02-19 | 0 | Details |
| US1700833A | Sound-recording system | Expired / Lapsed | 1928-01-30 | 1929-02-05 | 0 | Details |
| US1700454A | Electron emitter and process of making the same | Expired / Lapsed | 1924-07-08 | 1929-01-29 | 0 | Details |
| US1699567A | Radio signaling system | Expired / Lapsed | 1924-12-13 | 1929-01-22 | 0 | Details |
| US1696415A | Voltage-balance regulator | Expired / Lapsed | 1927-08-09 | 1928-12-25 | 0 | Details |
| US1695048A | Picture transmission | Expired / Lapsed | 1925-12-24 | 1928-12-11 | 0 | Details |
| US1690206A | Telephone system | Expired / Lapsed | 1927-06-04 | 1928-11-06 | 0 | Details |
| US1690299A | Generation and control of electric waves | Expired / Lapsed | 1922-03-21 | 1928-11-06 | 0 | Details |
| US1689206A | Apparatus for treating vulcanizable material | Expired / Lapsed | 1926-12-16 | 1928-10-30 | 0 | Details |
| US1689294A | Remote control and indicating system | Expired / Lapsed | 1925-11-27 | 1928-10-30 | 0 | Details |
| US1689348A | Combined jack and selecting switch | Expired / Lapsed | 1924-12-29 | 1928-10-30 | 0 | Details |
| US1689292A | Navigation-directing system | Expired / Lapsed | 1923-06-25 | 1928-10-30 | 0 | Details |
| US1688451A | Telephone signaling system | Expired / Lapsed | 1926-05-19 | 1928-10-23 | 0 | Details |
| US1688976A | Audiphone | Expired / Lapsed | 1924-06-21 | 1928-10-23 | 0 | Details |
| US1688991A | Electron-discharge device | Expired / Lapsed | 1923-10-29 | 1928-10-23 | 0 | Details |
| US1687524A | Material-feeding device | Expired / Lapsed | 1926-11-30 | 1928-10-16 | 0 | Details |
| US1687933A | Electrical signaling system | Expired / Lapsed | 1923-10-25 | 1928-10-16 | 0 | Details |
| US1687882A | Oscillation generator and modulator | Expired / Lapsed | 1923-03-31 | 1928-10-16 | 0 | Details |
| US1686585A | Telegraph cipher system | Expired / Lapsed | 1925-10-31 | 1928-10-09 | 0 | Details |
| US1684403A | Electrical testing system and method | Expired / Lapsed | 1926-05-29 | 1928-09-18 | 0 | Details |
| US1681566A | Manufacture of cables | Expired / Lapsed | 1924-08-26 | 1928-08-21 | 0 | Details |
| US1680367A | Repeater circuits | Expired / Lapsed | 1922-07-07 | 1928-08-14 | 0 | Details |
| US1678672A | Two-way radio telephone system | Expired / Lapsed | 1924-04-19 | 1928-07-31 | 0 | Details |
| US1677966A | Carrier signaling system | Expired / Lapsed | 1925-12-30 | 1928-07-24 | 0 | Details |
| US1677967A | Radio signaling system | Expired / Lapsed | 1924-05-29 | 1928-07-24 | 0 | Details |
| US1678116A | Device for the transmission of mechanical vibratory energy | Expired / Lapsed | 1923-10-16 | 1928-07-24 | 0 | Details |
| US1678101A | Air-conditioning system | Expired / Lapsed | 1923-06-29 | 1928-07-24 | 0 | Details |
| US1678203A | Communicating and switching system | Expired / Lapsed | 1923-02-27 | 1928-07-24 | 0 | Details |
| US1677224A | Carrier-receiving system | Expired / Lapsed | 1926-03-23 | 1928-07-17 | 0 | Details |
| US1677157A | System for measuring contact rebounding | Expired / Lapsed | 1925-02-25 | 1928-07-17 | 0 | Details |
| US1677191A | Modulating arrangement | Expired / Lapsed | 1923-05-26 | 1928-07-17 | 0 | Details |
| US1675894A | Method and apparatus for recording and reproducing sound | Expired / Lapsed | 1924-06-20 | 1928-07-03 | 0 | Details |
| US1673023A | Carrier-wave repeater | Expired / Lapsed | 1926-05-01 | 1928-06-12 | 0 | Details |
| US1673002A | Control of electric waves | Expired / Lapsed | 1923-02-23 | 1928-06-12 | 0 | Details |
| US1672049A | Alternating-current relay | Expired / Lapsed | 1926-03-29 | 1928-06-05 | 0 | Details |
| US1672215A | Wave varying and transmitting | Expired / Lapsed | 1923-08-15 | 1928-06-05 | 0 | Details |
| US1671151A | Method of and apparatus for reducing width of transmission … | Expired / Lapsed | 1924-12-10 | 1928-05-29 | 0 | Details |
| US1667792A | Radio signaling system | Expired / Lapsed | 1923-01-11 | 1928-05-01 | 0 | Details |
| US1666158A | System for binaural transmission of signals | Expired / Lapsed | 1925-12-31 | 1928-04-17 | 0 | Details |
| US1666680A | Dynamometer | Expired / Lapsed | 1922-12-30 | 1928-04-17 | 0 | Details |
| US1663890A | Electrical control system | Expired / Lapsed | 1924-11-19 | 1928-03-27 | 0 | Details |
| US1663086A | Means for indicating frequency changes | Expired / Lapsed | 1924-03-04 | 1928-03-20 | 0 | Details |
| US1659083A | Telephone-exchange system | Expired / Lapsed | 1925-06-27 | 1928-02-14 | 0 | Details |
| US1658095A | Feeding device for belt conveyers | Expired / Lapsed | 1925-12-14 | 1928-02-07 | 0 | Details |
| US1658094A | Paper-conveying system | Expired / Lapsed | 1925-12-05 | 1928-02-07 | 0 | Details |
| US1658337A | Carrier-wave signaling system | Expired / Lapsed | 1924-06-21 | 1928-02-07 | 0 | Details |
| US1657462A | Nonsinging reamplifying circuits | Expired / Lapsed | 1923-05-15 | 1928-01-31 | 0 | Details |
| US1656956A | Electric vacuum valve tubb | Expired / Lapsed | 1921-03-30 | 1928-01-24 | 0 | Details |
| US1655557A | Amplifier circuits | Expired / Lapsed | 1919-11-07 | 1928-01-10 | 0 | Details |
| US1655061A | Telephone-exchange system | Expired / Lapsed | 1926-08-28 | 1928-01-03 | 0 | Details |
| US1654633A | Recording system | Expired / Lapsed | 1925-01-30 | 1928-01-03 | 0 | Details |
| US1654645A | Recording system | Expired / Lapsed | 1925-01-30 | 1928-01-03 | 0 | Details |
| US1653736A | Impulse-registering device | Expired / Lapsed | 1924-07-11 | 1927-12-27 | 0 | Details |
| US1653694A | Apparatus and method for measuring transmitted light | Expired / Lapsed | 1923-12-15 | 1927-12-27 | 0 | Details |
| US1649819A | System of television | Expired / Lapsed | 1926-01-30 | 1927-11-22 | 0 | Details |
| US1648058A | Electrovision | Expired / Lapsed | 1925-11-25 | 1927-11-08 | 0 | Details |
| US1645810A | Direction finding and indicating system | Expired / Lapsed | 1921-01-08 | 1927-10-18 | 0 | Details |
| US1640524A | Means for detecting metal particles in nonmetallic material | Expired / Lapsed | 1921-02-24 | 1927-08-30 | 0 | Details |
| US1639000A | Wave modulation | Expired / Lapsed | 1924-01-04 | 1927-08-16 | 0 | Details |
| US1638925A | High-frequency signaling system | Expired / Lapsed | 1922-08-16 | 1927-08-16 | 0 | Details |
| US1637404A | Signaling system | Expired / Lapsed | 1921-03-12 | 1927-08-02 | 0 | Details |
| US1633577A | Electrical coil | Expired / Lapsed | 1925-12-22 | 1927-06-28 | 0 | Details |
| US1633082A | Distribution of intelligence | Expired / Lapsed | 1922-01-25 | 1927-06-21 | 0 | Details |
| US1633100A | Plural channel signaling | Expired / Lapsed | 1916-03-03 | 1927-06-21 | 0 | Details |
| US1632076A | Method of determining inequalities in wall thickness of tub… | Expired / Lapsed | 1925-04-22 | 1927-06-14 | 0 | Details |
| US1631963A | Transmission of pictures by electricity | Expired / Lapsed | 1923-12-31 | 1927-06-14 | 0 | Details |
| US1631958A | Pneumatic relay | Expired / Lapsed | 1923-12-12 | 1927-06-14 | 0 | Details |
| US1632054A | Oscillation generator | Expired / Lapsed | 1923-12-03 | 1927-06-14 | 0 | Details |
| US1632106A | Signaling system | Expired / Lapsed | 1923-11-24 | 1927-06-14 | 0 | Details |
| US1630451A | Method of producing coated cores | Expired / Lapsed | 1925-02-14 | 1927-05-31 | 0 | Details |
| US1629100A | Transmission system | Expired / Lapsed | 1923-12-21 | 1927-05-17 | 0 | Details |
| US1629009A | Low-impedance electric discharge device | Expired / Lapsed | 1920-08-07 | 1927-05-17 | 0 | Details |
| US1625449A | Method of molding phenol plastic or like compounds | Expired / Lapsed | 1921-08-05 | 1927-04-19 | 0 | Details |
| US1624422A | Dial-testing circuit | Expired / Lapsed | 1926-06-30 | 1927-04-12 | 0 | Details |
| US1624672A | Communication system | Expired / Lapsed | 1924-12-17 | 1927-04-12 | 0 | Details |
| US1624601A | Secret communication | Expired / Lapsed | 1923-07-02 | 1927-04-12 | 0 | Details |
| US1621480A | Testing system | Expired / Lapsed | 1926-08-31 | 1927-03-15 | 0 | Details |
| US1620204A | Frequency indication and control | Expired / Lapsed | 1924-12-29 | 1927-03-08 | 0 | Details |
| US1618242A | Time-announcing system | Expired / Lapsed | 1925-02-09 | 1927-02-22 | 0 | Details |
| US1617392A | Carrier-wave-transmission system | Expired / Lapsed | 1924-03-04 | 1927-02-15 | 0 | Details |
| US1617991A | Synchronizing system | Expired / Lapsed | 1923-12-24 | 1927-02-15 | 0 | Details |
| US1616622A | Oscillation generator with automatic frequency control | Expired / Lapsed | 1923-05-21 | 1927-02-08 | 0 | Details |
| US1616186A | Control and supervisory system | Expired / Lapsed | 1921-06-30 | 1927-02-01 | 0 | Details |
| US1613686A | Method of and apparatus for secret electrical transmission … | Expired / Lapsed | 1924-12-05 | 1927-01-11 | 0 | Details |
| US1612952A | Radio receiving apparatus | Expired / Lapsed | 1921-08-24 | 1927-01-04 | 0 | Details |
| US1611932A | Frequency selective-current transmission | Expired / Lapsed | 1921-12-17 | 1926-12-28 | 0 | Details |
| US1611223A | Apparatus for controlling the frequency of an alternating c… | Expired / Lapsed | 1923-12-19 | 1926-12-21 | 0 | Details |
| US1611716A | Measuring electrical quantities | Expired / Lapsed | 1921-07-09 | 1926-12-21 | 0 | Details |
| US1610910A | Composite article and method of forming it | Expired / Lapsed | 1924-10-16 | 1926-12-14 | 0 | Details |
| US1608551A | Radio signaling system | Expired / Lapsed | 1925-12-30 | 1926-11-30 | 0 | Details |
| US1608527A | Facsimile telegraph system | Expired / Lapsed | 1921-07-20 | 1926-11-30 | 0 | Details |
| US1606792A | Oscillation generator for current of continuously varying f… | Expired / Lapsed | 1919-10-06 | 1926-11-16 | 0 | Details |
| US1606164A | Circuit-controlling device | Expired / Lapsed | 1923-05-09 | 1926-11-09 | 0 | Details |
| US1604163A | Means for regulating motors | Expired / Lapsed | 1923-09-05 | 1926-10-26 | 0 | Details |
| US1602469A | Electrical transmission of pictures | Expired / Lapsed | 1923-12-20 | 1926-10-12 | 0 | Details |
| US1598673A | Secrecy communication system | Expired / Lapsed | 1920-12-18 | 1926-09-07 | 0 | Details |
| US1596102A | High-frequency translating circuits | Expired / Lapsed | 1924-12-24 | 1926-08-17 | 0 | Details |
| US1593640A | Neutralization of inductive interference | Expired / Lapsed | 1924-05-13 | 1926-07-27 | 0 | Details |
| US1593993A | Selective system | Expired / Lapsed | 1921-11-10 | 1926-07-27 | 0 | Details |
| US1593387A | Telephone-exchange system | Expired / Lapsed | 1924-07-05 | 1926-07-20 | 0 | Details |
| US1592940A | Secret signaling | Expired / Lapsed | 1920-09-09 | 1926-07-20 | 0 | Details |
| US1592274A | Employment of cathode ray oscillographs | Expired / Lapsed | 1924-06-28 | 1926-07-13 | 0 | Details |
| US1589405A | Ringing arrangement for carrier circuits | Expired / Lapsed | 1924-04-01 | 1926-06-22 | 0 | Details |
| US1586533A | Thermionic meter | Expired / Lapsed | 1922-04-27 | 1926-06-01 | 0 | Details |
| US1587122A | Electrical switching and indicating system | Expired / Lapsed | 1921-12-31 | 1926-06-01 | 0 | Details |
| US1587121A | Remote control and supervisory system | Expired / Lapsed | 1921-12-01 | 1926-06-01 | 0 | Details |
| US1579263A | Electrical transmission of pictures | Expired / Lapsed | 1924-03-26 | 1926-04-06 | 0 | Details |
| US1577722A | Generation and control of electric waves | Expired / Lapsed | 1922-04-24 | 1926-03-23 | 0 | Details |
| US1574780A | Means for and method of modulation | Expired / Lapsed | 1921-10-05 | 1926-03-02 | 0 | Details |
| US1573801A | Trouble-alarm system for radio receiving sets | Expired / Lapsed | 1923-10-05 | 1926-02-23 | 0 | Details |
| US1574350A | Electrical testing | Expired / Lapsed | 1923-08-14 | 1926-02-23 | 0 | Details |
| US1573983A | Secret signaling | Expired / Lapsed | 1923-08-08 | 1926-02-23 | 0 | Details |
| US1572869A | Electromagnet | Expired / Lapsed | 1923-12-15 | 1926-02-16 | 0 | Details |
| US1573303A | Carrier-wave transmission | Expired / Lapsed | 1922-10-21 | 1926-02-16 | 0 | Details |
| US1572756A | High-frequency-wave signaling and communicating system | Expired / Lapsed | 1921-05-14 | 1926-02-09 | 0 | Details |
| US1570948A | Test fixture | Expired / Lapsed | 1923-08-27 | 1926-01-26 | 0 | Details |
| US1565869A | Etching | Expired / Lapsed | 1923-12-20 | 1925-12-15 | 0 | Details |
| US1565596A | Signal system | Expired / Lapsed | 1923-11-15 | 1925-12-15 | 0 | Details |
| US1565613A | Electrical measuring apparatus | Expired / Lapsed | 1923-02-10 | 1925-12-15 | 0 | Details |
| US1563326A | Secret-communication system | Expired / Lapsed | 1921-11-08 | 1925-12-01 | 0 | Details |
| US1559642A | Signaling with phase reversals | Expired / Lapsed | 1923-08-28 | 1925-11-03 | 0 | Details |
| US1560056A | Source of waves of constant frequency | Expired / Lapsed | 1923-05-01 | 1925-11-03 | 0 | Details |
| US1559656A | Method of and means for increasing voltages | Expired / Lapsed | 1921-04-26 | 1925-11-03 | 0 | Details |
| US1559867A | Wave-transmission system | Expired / Lapsed | 1919-08-29 | 1925-11-03 | 0 | Details |
| US1552590A | Acoustical and for deaf persons | Expired / Lapsed | 1921-12-21 | 1925-09-08 | 0 | Details |
| US1550660A | Prevention of overloading in speech circuits | Expired / Lapsed | 1924-09-19 | 1925-08-25 | 0 | Details |
| US1549907A | Telegraphy | Expired / Lapsed | 1920-11-11 | 1925-08-18 | 0 | Details |
| US1548895A | Electrical transmission of pictures | Expired / Lapsed | 1923-01-26 | 1925-08-11 | 0 | Details |
| US1548952A | Electric control circuits | Expired / Lapsed | 1921-11-04 | 1925-08-11 | 0 | Details |
| US1548022A | Inductance device | Expired / Lapsed | 1923-04-23 | 1925-08-04 | 0 | Details |
| US1548028A | Transmission system | Expired / Lapsed | 1918-10-07 | 1925-08-04 | 0 | Details |
| US1547242A | Carrier transmission over power circuits | Expired / Lapsed | 1924-04-29 | 1925-07-28 | 0 | Details |
| US1543836A | Signaling system | Expired / Lapsed | 1920-11-26 | 1925-06-30 | 0 | Details |
| US1543671A | Telephone system | Expired / Lapsed | 1920-04-23 | 1925-06-30 | 0 | Details |
| US1541311A | Vacuum-tube circuits | Expired / Lapsed | 1923-02-07 | 1925-06-09 | 0 | Details |
| US1535538A | Vibratory system | Expired / Lapsed | 1923-01-03 | 1925-04-28 | 0 | Details |
| US1533311A | Secret signaling | Expired / Lapsed | 1923-12-18 | 1925-04-14 | 0 | Details |
| US1531633A | Oscillation generator | Expired / Lapsed | 1920-12-22 | 1925-03-31 | 0 | Details |
| US1530648A | Electric circuits | Expired / Lapsed | 1920-03-17 | 1925-03-24 | 0 | Details |
| US1523398A | Method of and apparatus for locating faults | Expired / Lapsed | 1922-11-20 | 1925-01-20 | 0 | Details |
| US1522581A | Radio broadcasting system | Expired / Lapsed | 1922-08-16 | 1925-01-13 | 0 | Details |
| US1520097A | Selective signaling system | Expired / Lapsed | 1923-12-03 | 1924-12-23 | 0 | Details |
| US1518543A | Electrical measuring apparatus | Expired / Lapsed | 1921-10-28 | 1924-12-09 | 0 | Details |
| US1514753A | Signal-receiving system | Expired / Lapsed | 1920-11-19 | 1924-11-11 | 0 | Details |
| US1514751A | Vacuum-tube oscillator chronometer | Expired / Lapsed | 1920-08-24 | 1924-11-11 | 0 | Details |
| US1505158A | Frequency-control system | Expired / Lapsed | 1921-11-23 | 1924-08-19 | 0 | Details |
| US1504275A | Automatic telephone-exchange system | Expired / Lapsed | 1921-06-23 | 1924-08-12 | 0 | Details |
| US1504882A | Method and apparatus for transmitting signals | Expired / Lapsed | 1920-01-16 | 1924-08-12 | 0 | Details |
| US1502243A | System for determining the direction of propagation of wave… | Expired / Lapsed | 1920-11-13 | 1924-07-22 | 0 | Details |
| US1498544A | Electrical selective system | Expired / Lapsed | 1920-03-09 | 1924-06-24 | 0 | Details |
| US1496818A | Electrical switching circuit | Expired / Lapsed | 1920-12-21 | 1924-06-10 | 0 | Details |
| US1497299A | System of wave transmission | Expired / Lapsed | 1917-06-29 | 1924-06-10 | 0 | Details |
| US1495429A | Piezophony | Expired / Lapsed | 1918-04-10 | 1924-05-27 | 0 | Details |
| US1493586A | Measuring and recording device | Expired / Lapsed | 1922-12-30 | 1924-05-13 | 0 | Details |
| US1481284A | Means for and method of amplitude selection | Expired / Lapsed | 1921-10-05 | 1924-01-22 | 0 | Details |
| US1479051A | Artificial line | Expired / Lapsed | 1920-05-14 | 1924-01-01 | 0 | Details |
| US1477017A | Current-controlling and static-reducing system | Expired / Lapsed | 1919-05-02 | 1923-12-11 | 0 | Details |
| US1472505A | Method of making electrodes | Expired / Lapsed | 1920-04-16 | 1923-10-30 | 0 | Details |
| US1466284A | Detecting system | Expired / Lapsed | 1919-06-24 | 1923-08-28 | 0 | Details |
| US1465352A | Electrical testing system | Expired / Lapsed | 1920-09-27 | 1923-08-21 | 0 | Details |
| US1464565A | Call system for radiotelephony | Expired / Lapsed | 1921-04-13 | 1923-08-14 | 0 | Details |
| US1464096A | Secret signaling | Expired / Lapsed | 1920-08-28 | 1923-08-07 | 0 | Details |
| US1463795A | Translating circuit | Expired / Lapsed | 1918-10-10 | 1923-08-07 | 0 | Details |
| US1462053A | Electrical testing system | Expired / Lapsed | 1920-11-13 | 1923-07-17 | 0 | Details |
| US1462035A | Treatment of magnetic material | Expired / Lapsed | 1920-08-10 | 1923-07-17 | 0 | Details |
| US1458949A | Carrier radiotelephone system | Expired / Lapsed | 1922-01-07 | 1923-06-19 | 0 | Details |
| US1441270A | Transmission system | Expired / Lapsed | 1919-09-26 | 1923-01-09 | 0 | Details |
| US1438976A | Electric regulator | Expired / Lapsed | 1918-06-08 | 1922-12-19 | 0 | Details |
| US1433599A | Radiocircuit | Expired / Lapsed | 1921-07-02 | 1922-10-31 | 0 | Details |
| US1428156A | Low-frequency amplifier | Expired / Lapsed | 1919-09-26 | 1922-09-05 | 0 | Details |
| US1426826A | Electron-discharge-device circuits | Expired / Lapsed | 1917-07-19 | 1922-08-22 | 0 | Details |
| US1419090A | Covering machine | Expired / Lapsed | 1921-08-12 | 1922-06-06 | 0 | Details |
| US1412405A | Method for testing transmitters | Expired / Lapsed | 1920-11-02 | 1922-04-11 | 0 | Details |
| US1410890A | Method of and means for modulating carrier oscillations | Expired / Lapsed | 1918-08-08 | 1922-03-28 | 0 | Details |
| US1406996A | Electric-wave-ranging system | Expired / Lapsed | 1920-09-30 | 1922-02-21 | 0 | Details |
| US1403841A | Frequency-control system | Expired / Lapsed | 1919-09-30 | 1922-01-17 | 0 | Details |
| US1399997A | Telegraph system | Expired / Lapsed | 1918-01-03 | 1921-12-13 | 0 | Details |
| US1397228A | Electrical measuring apparatus | Expired / Lapsed | 1920-09-03 | 1921-11-15 | 0 | Details |
| US1394642A | Electric signaling system | Expired / Lapsed | 1919-11-12 | 1921-10-25 | 0 | Details |
| US1387240A | Stroboscopic system | Expired / Lapsed | 1918-02-14 | 1921-08-09 | 0 | Details |
| US1383703A | Method of insulating metal particles | Expired / Lapsed | 1920-01-21 | 1921-07-05 | 0 | Details |
| US1381640A | Detecting underwater vibrations | Expired / Lapsed | 1919-06-24 | 1921-06-14 | 0 | Details |
| US1381451A | Switching system | Expired / Lapsed | 1919-06-24 | 1921-06-14 | 0 | Details |
| US1378960A | Method of and apparatus for detecting under-water vibrations | Expired / Lapsed | 1919-06-24 | 1921-05-24 | 0 | Details |
| US1378950A | Recording-key | Expired / Lapsed | 1918-12-04 | 1921-05-24 | 0 | Details |
| US1370669A | Machine-telegraph | Expired / Lapsed | 1915-12-14 | 1921-03-08 | 0 | Details |
| US1366617A | Telegraphone | Expired / Lapsed | 1916-10-28 | 1921-01-25 | 0 | Details |
| US1345717A | Acoustic device | Expired / Lapsed | 1918-08-09 | 1920-07-06 | 0 | Details |
| US1337681A | Telephone-exchange system | Expired / Lapsed | 1917-03-29 | 1920-04-20 | 0 | Details |
| US1332961A | Signaling system | Expired / Lapsed | 1918-06-06 | 1920-03-09 | 0 | Details |
| US1320980A | Transformer. | Expired / Lapsed | 1918-09-21 | 1919-11-04 | 0 | Details |
| US1301644A | Directive sending system. | Expired / Lapsed | 1915-09-13 | 1919-04-22 | 0 | Details |
| US1296653A | Container for electrical apparatus. | Expired / Lapsed | 1916-12-18 | 1919-03-11 | 0 | Details |
| US1295454A | Transmission-circuit. | Expired / Lapsed | 1916-08-30 | 1919-02-25 | 0 | Details |
| US1292206A | Magnet-core. | Expired / Lapsed | 1918-06-28 | 1919-01-21 | 0 | Details |
| US1287982A | Modulating system. | Expired / Lapsed | 1917-02-16 | 1918-12-17 | 0 | Details |
| US1283563A | Contact-bank. | Expired / Lapsed | 1917-11-03 | 1918-11-05 | 0 | Details |
| US1279882A | Signaling system. | Expired / Lapsed | 1917-08-27 | 1918-09-24 | 0 | Details |
| US1271320A | Electric conductor. | Expired / Lapsed | 1916-09-11 | 1918-07-02 | 0 | Details |
| US1262323A | Telephone-exchange system. | Expired / Lapsed | 1917-10-29 | 1918-04-09 | 0 | Details |
| US1262359A | Impulse-transmitting device. | Expired / Lapsed | 1916-10-11 | 1918-04-09 | 0 | Details |
| US1252502A | Protective circuit. | Expired / Lapsed | 1915-02-09 | 1918-01-08 | 0 | Details |
| US1251750A | Testing arrangement. | Expired / Lapsed | 1916-07-24 | 1918-01-01 | 0 | Details |
| US1246964A | Electric cable. | Expired / Lapsed | 1917-02-17 | 1917-11-20 | 0 | Details |
| US1196761A | Telephone system. | Expired / Lapsed | 1915-05-11 | 1916-09-05 | 0 | Details |
| US1132094A | Contact member. | Expired / Lapsed | 1911-09-08 | 1915-03-16 | 0 | Details |
| US1046823A | Electrical switch-contact. | Expired / Lapsed | 1908-02-27 | 1912-12-10 | 0 | Details |
| US1039988A | Controlling apparatus. | Expired / Lapsed | — | 1912-10-01 | 0 | Details |
| US794112A | Service-meter for party telephone-lines. | Expired / Lapsed | 1903-01-29 | 1905-07-04 | 0 | Details |