US3624645A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oscillator keyboard with roll and double-strike control
Assignee: Unisys Corp
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Filing: 1969-12-15
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Granted: 1971-11-30
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Expires: 1989-12-15
Abstract
Abstract A solid-state keyboard for producing a coded output to an associated data processor. Depression of any single key activates an encoder and a circuit which produces a signal for gating the encoder output into the processor. A further circuit detects when a second key is depressed before a first key is released and, if the time between depression of the keys is less than a fixed interval, an alarm is sounded. If the time between depression of the two keys is greater than the fixed interval, the gating signal for the data represented by the second key is inhibited until after the first key is released.
Inventors
- 👤 Julius Gluck
- 👤 Warren R Wines
- 👤 Joseph J Laszlo
- 👤 Nanjundiah N Murthy
- 👤 Klaus E Grund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:11
CPC Classifications
H; H04; H04L; H04L13/00; H04L13/16; H03; H03M; H03M11/00; H03M11/02
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
72 words
The improvement as claimed in claim 1 and further comprising: fourth means connected to the output of said constant current generator for sensing when at least two of said switch circuits are actuated, said fourth means producing an output signal as long as at least two of said switch circuits are actuated; and, means responsive to the output signal of said fourth means for inhibiting the output signal of said second means.
Claim 2
Dependent Claim
59 words
The improvement as claimed in claim 2 and further comprising: a timing circuit responsive to said second means for producing a timing signal of predetermined duration; and, a comparison circuit responsive to said timing circuit and said fourth means for producing an error signal if said fourth means produces an output signal while said timing signal is being produced.
Claim 3
Dependent Claim
27 words
The improvement as claimed in claim 3 and further comprising: a loudspeaker; and, means responsive to said error signal for feeding an audio signal to said loudspeaker.
Claim 4
Dependent Claim
44 words
The improvement as claimed in claim 4 wherein said fourth means includes trigger means for sensing the voltage at the output of said constant current generator and said second means includes trigger means for sensing the voltages in individual ones of said parallel paths.
Claim 5
Dependent Claim
69 words
The improvement as claimed in claim 2, wherein said third means includes pulse forming circuitry for producing said gating signal in predetermined timed relation to the leading edge portion of each output signal from said second means, the termination of said output signal from said fourth means, while one of said switching circuits remains actuated, being operative to provide, in effect, an additional output signal from said second means.
Claim 6
Dependent Claim
164 words
In an electronic keyboard having a plurality of selectively operable keys, the improvement comprising: an oscillator; a constant current generator having an output; a voltage source; a plurality of switch circuits, one for each of said keys, and each comprising, a transistor having an emitter connected to a voltage source, a collector connected through a resistor to the output of said constant current generator, and, a parallel resonant circuit including a coil and a capacitor connected between said voltage source and the base of the transistor, means connecting said oscillator to the base of each of said transistors; means mounted on each said key for selectively tuning or detuning the parallel resonant circuit of the corresponding key switch to thereby turn on the corresponding transistor whereby parallel current paths are established between said voltage source and said constant current generator when a plurality of said keys are operated; and, means electrically connected to said transistors for producing an indication corresponding to the operated keys.
Claim 7
Dependent Claim
79 words
The improvement as claimed in claim 7 and further comprising: first means including first trigger means for producing a first signal as long as any one of said transistors is on; second means including second trigger means for producing a second signal as long as any two or more of said transistors is on; and, third means responsive to said second means for inhibiting said first signal as long as any two or more of said transistors is on.
Claim 8
Dependent Claim
30 words
The improvement as claimed in claim 8 wherein said second trigger means is connected between the output of said constant current source and said resistors to sense the voltage thereat.
Claim 9
Dependent Claim
34 words
The improvement as claimed in claim 9 and further comprising: further means responsive to said first and third means for producing a gating pulse of fixed duration each time said first signal is initiated.
Claim 10
Dependent Claim
60 words
The improvement as claimed in claim 10 and further comprising: timing means responsive to said further means for producing a timing signal of predetermined duration each time a said gating signal is produced; and, means responsive to said timing means and said second means for producing an error signal if a said second signal occurs during a said timing signal.
Claim 11
Dependent Claim
36 words
The improvement as claimed in claim 11 wherein each switch circuit includes a diode said first trigger means being connected through said diodes to the collectors of each of said transistors to sense the voltages thereat.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-29 | 1975-05-31 | 1975-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-29 | 1979-05-31 | 1979-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-29 | 1983-05-31 | 1983-11-30 | $7700.00 | Window Closed / Lapsed |