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US3742222A
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US
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Photoelectric sensing system
Assignee: ENDL ELEKTRONIK CO GmbH Co
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Filing: 1971-02-09
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Granted: 1973-06-26
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Expires: 1991-02-09
Abstract
Abstract A multiple light beam sensing system with pulsed light sources, plural light sensors and a digital circuit responsive to each of the sensors to detect the interruption of light to any sensor. One digital detector circuit uses an AND gate; and another has a series of bistable circuits actuated between stable states by pulses from the sensors. An output signal is present so long as no beam is broken. The interruption of one beam or the failure of any component is indicated by the loss of the output signal. A current generator light sensor is shunted by an inductor which has a low impedance at the frequency of ambient light and a high impedance at the light source pulse repetition rate, providing a high degree of discrimination against ambient light. The light source and light sensor are mounted adjacent each other at one side of the sensing area. A reflector is mounted at the other side. A single lens directs light from the source to the reflector and directs reflected light to the sensor.
Inventors
- 👤 A Endl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:32
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/18; G08B13/181; G08B13/183; F; F16; F16P; F16P3/00; F16P3/12; F16P3/14; F16P3/144; G08B13/184; H; H02; H02H; H02H5/00; H02H5/10
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
160 words
A photoelectric system for determining when an object is within a defined space, comprising: light source means for projecting a plurality of adjacent parallel light beams through said defined space; oscillator means for generating periodically recurring pulses, connected with said light source means whereby said light beams are pulsed in accordance therewith; a plurality of light sensors corresponding to said plurality of light beams and each located for intercepting a different one of said light beams to produce a pulsed signal dependent on receipt of the corresponding pulsed light beam; and digital detector means having a plurality of signal inputs each coupled to a different one of said light sensors for producing a first output signal, indicating the absence of an object within the defined space during receipt of pulsed light beams at each input, and a second output signal, indicating the presence of an object within said defined space upon interruption of any one of said pulsed light beams.
Claim 2
Dependent Claim
160 words
A photoelectric system for determining when an object is within a defined space, comprising: light source means for projecting a plurality of adjacent parallel light beams through said defined space; oscillator means for generating periodically recurring pulses, connected with said light source means whereby said light beams are pulsed in accordance therewith; a plurality of light sensors corresponding to said plurality of light beams and each located for intercepting a different one of said light beams to produce a pulsed signal dependent on receipt of the corresponding pulsed light beam; and digital detector means having a plurality of signal inputs each coupled to a different one of said light sensors for producing a first output signal, indicating the absence of an object within the defined space during receipt of pulsed light beams at each input, and a second output signal, indicating the presence of an object within said defined space upon interruption of any one of said pulsed light beams.
Claim 3
Dependent Claim
53 words
The photoelectric system of claim 1 wherein said digital detector means produces an output dependent on the signals at the inputs, said digital detector means being sensitive to the receipt of a light beam by each light sensor and insensitive to the total quantity of light received by the plurality of light sensors.
Claim 4
Dependent Claim
61 words
The photoelectric system of claim 1 wherein each input of said digital detector means assumes one of two states, each light sensor being coupled to a different one of said plurality of inputs such that signals above a predetermined value correspond to an input of one state and signals below said predetermined value correspond to an input of the other state.
Claim 5
Dependent Claim
60 words
The photoelectric system of claim 3 wherein said digital detector means comprises logic means for producing one of two states at an output only when all of said plurality of inputs assume a common state, and switching means responsive when said output of said logic means assumes the other of said two states to indicate the presence of said object.
Claim 6
Dependent Claim
73 words
The photoelectric system of claim 4 wherein said switching means includes pulse stretcher means having an input coupled to the output of said logic means and an output for opening or closing a circUit to indicate the presence of said object, said pulse stretcher means being responsive to said one state to generate an output pulse having a time period in excess of the time period of the pulses from said oscillator means.
Claim 7
Dependent Claim
54 words
The photoelectric system of claim 3 wherein said digital detector means includes bistable means for establishing an output dependent on the states at a pair of inputs, and means coupling one of said light sensors to one of said inputs and means coupling another of said light sensors to the other of said inputs.
Claim 8
Dependent Claim
33 words
The photoelectric system of claim 6 wherein said digital detector means produces an indication of the absence of an object when the output of said bistable means continuously alternates between two stable states.
Claim 9
Dependent Claim
142 words
The photoelectric system of claim 7 wherein said light source means projects a plurality of light beams in excess of two, said digital means includes at least two additional bistable means each having a pair of inputs and an output, said coupling means includes means coupling one of said photo detectors in excess of two to an input of one of said additional bistable means, circuit means for providing a signal to the remaining input of said one additional bistable means, and said digital means includes means connecting an output of the first named bistable means to one input of the other additional bistable means and means coupling the output of said one additional bistable means to the other input of said other additional bistable means, said output of said bistable means corresponding to the output of said other additional bistable means.
Claim 10
Dependent Claim
37 words
The photoelectric system of claim 8 in which said light source means produces an odd number of light beams, and said circuit means couples the oscillator means to said remaining input of said one additional bistable means.
Claim 11
Dependent Claim
62 words
The photoelectric system of claim 7 wherein said digital detector means incldues rectifier means for producing a continuous signal when said bistable means has said continuously alternating output, AC coupling means for connecting said rectifier means to said output of said bistable means, and means responsive when the continuous signal of said rectifier means terminates for indicating the presence of said object.
Claim 12
Dependent Claim
65 words
The photoelectric system of claim 3 wherein said digital detector means includes bistable means for establishing an output dependent on the states at a pair of inputs, and said digital detector means includes means coupling one of said light sensors to one of said inputs of said bistable means, and means coupling said oscillator means to the other of said inputs of said bistable means.
Claim 13
Dependent Claim
52 words
The photoelectric system of claim 1 wherein said light source means comprises a plurality of light emitting semiconductor diodes for emitting radiation when energized by a pulse, in which said oscillator means is connected to each of said diodes, wherein the radiation from each diode corresponds to one of said light beams.
Claim 14
Dependent Claim
58 words
The photoelectric sensing system of claim 1 wherein the first output signal of said digital detector means is an alternating signal and the second output signal has no alternating component, and including a transformer connected with the output of the digital detector means and a utilization circuit connected through said transformer to the output of said digital detector.
Claim 15
Dependent Claim
78 words
The photoelectric system of claim 1, operable in an environment subject to interfering ambient light which is continuous or at a low frequency, wherein the pulses generated by said oscillator means have a frequency higher than the frequency of the ambient light, said system including a means having a high frequency pass characteristic for filtering the signals from said light sensors so that only high frequency components thereof are connected with the inputs of said digital detector means.
Claim 16
Dependent Claim
71 words
A photoelectric detector comprising: a plurality of light sources; a plurality of light sensors receiving light from said plurality Of sources; detector means responsive to said light sensors for sensing the interruption of light received by any one sensor; and means responsive to said detector means for reducing the intensity of light emitted from all of said light sources upon the interruption of the light received by one of said sensors.
Claim 17
Dependent Claim
71 words
A photoelectric detector comprising: a plurality of light sources; a plurality of light sensors receiving light from said plurality Of sources; detector means responsive to said light sensors for sensing the interruption of light received by any one sensor; and means responsive to said detector means for reducing the intensity of light emitted from all of said light sources upon the interruption of the light received by one of said sensors.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-25 | 1976-12-25 | 1977-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-25 | 1980-12-25 | 1981-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-25 | 1984-12-25 | 1985-06-26 | $7700.00 | Window Closed / Lapsed |