Patent US3603957A successfully refreshed from Google Patents.
US3603957A
Expired / Lapsed
US
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Intrusion alarm system and line voltage compensation
Assignee: Individual
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Filing: 1969-01-02
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Granted: 1971-09-07
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Expires: 1989-01-02
Abstract
Abstract An intrusion alarm system responsive to the amount and rate of decrease of light striking a photohead is provided together with a means to compensate for those line voltage fluctuations which would produce a rapid decrease in light that might trigger a false alarm. The intrusion alarm system employs a pulse amplifier to respond to sudden decreases in light input to a photohead so as to provide a signal which will initiate the alarm. A rectifier coupled to the same line source as is connected to the source of light provides a rectified output having substantial ripple content. A diode bridge sensor compares the rectifier output with a voltage level on a capacitor, thereby establishing a means to provide a signal indicating sharp changes in line voltage level. A gate responsive to rectifier bridge output and thus responsive to sharp changes in line voltage level is used to disable the system on the incidence of such line voltage changes. Accordingly, false alarms are avoided.
Inventors
- 👤 Floyd S Merchant
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:53
CPC Classifications
G; G08; G08B; G08B29/00; G08B29/18; G08B29/185
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
95 words
An intrusion alarm system having a light source, a photohead responsive to said light source and a pulse amplifier coupled to the photohead to provide an alarm actuating signal, the improvement comprising: a line voltage compensating unit responsive to the line voltage source to which the light source is connected to provide an output signal in response to a sudden change in line voltage level, and a gate responsive to said output signal from said line voltage compensating unit to disable said alarm actuating signal when said line voltage compensating unit generates said output signal.
Claim 2
Dependent Claim
95 words
An intrusion alarm system having a light source, a photohead responsive to said light source and a pulse amplifier coupled to the photohead to provide an alarm actuating signal, the improvement comprising: a line voltage compensating unit responsive to the line voltage source to which the light source is connected to provide an output signal in response to a sudden change in line voltage level, and a gate responsive to said output signal from said line voltage compensating unit to disable said alarm actuating signal when said line voltage compensating unit generates said output signal.
Claim 3
Dependent Claim
130 words
The intrusion alarm system of claim 1 wherein said line voltage compensating unit comprises: a rectifier responsive to the line voltage source to provide a rectified output, a capacitor, a sensing bridge having first and second opposed corners, said first corner being coupled to the output of said rectifier and said second corner being coupled to said capacitor, whereby said sensing bridge will provide an output signal at a corner other than at said first and second opposed corners whenever the output of said rectifier changes at a rapid rate and whereby a long term change in the output level of said rectifier will be coupled through said bridge to said capacitor so that the voltage of said capacitor will follow changes in the voltage output level of said rectifier.
Claim 4
Dependent Claim
84 words
The intrusion alarm system of claim 2 wherein: said rectifier unit includes a filter having a time constant sufficiently short so as to cause said rectifier output to be responsive to sudden changes in line voltage level and to provide sufficient ripple content in the output of said rectifier so that during a short portion of each cycle of ripple current said line voltage compensating unit provides a biasing output, said biasing output being sufficiently low so that said gate is not responsive thereto.
Claim 5
Dependent Claim
54 words
The intrusion alarm system of claim 2 wherein said sensing bridge comprises: four arms each containing a diode, the junctions of said arms serving to define said first and said second opposed corners and also to define third and fourth opposed corners, and a resistor connected between said third and said fourth opposed corners.
Claim 6
Dependent Claim
47 words
The intrusion alarm system of claim 4 wherein: the anode of a first diode and the cathode of a second diode are connected to said first corner, and the anode of a third diode and the cathode of a fourth diode are connected to said second corner.
Claim 7
Dependent Claim
68 words
The intrusion alarm system of claim 4 further comprising: a valve having its input circuit coupled across said third and said fourth corners of said bridge, whereby a rapid change in the output voltage level from said rectifier sufficient to cause the arms of said bridge to conduct will couple biasing voltages to said valve, said biasing voltages having polarities tendinG to change the state of said valve.
Claim 8
Dependent Claim
63 words
The intrusion alarm system of claim 4 further comprising: a first bypass resistor connected across a first one of said diodes in a first arm of said bridge, and a second bypass resistor coupled across a second one of said diode in a second arm of said bridge, said first and said second arms of said bridge being opposed arms of said bridge.
Claim 9
Dependent Claim
21 words
The intrusion alarm system of claim 2 further comprising: a momentary manually operable normally open shorting contact coupled across said capacitor.
Claim 10
Dependent Claim
95 words
The intrusion alarm system of claim 6 further characterized by: a second photohead to respond to ambient light conditions which may tend to initiate a false alarm, and a second pulse amplifier coupled to the output of said second photohead to provide a second output signal in response to a sudden decrease in the light incident on said second photohead, said second output signal being coupled to said input circuit of said valve, whereby the incidence of said light conditions will bias said valve in a direction tending to change the state of said valve.
Claim 11
Dependent Claim
84 words
The intrusion alarm system of claim 6 wherein: said rectifier unit includes a filter having a time constant sufficiently short so as to cause said rectifier output to be responsive to sudden changes in line voltage level and to provide sufficient ripple content in the output of said rectifier so that during a short portion of each cycle of ripple current said line voltage compensating unit provides a biasing output, said biasing output being sufficiently low so that said gate is not responsive thereto.
Claim 12
Dependent Claim
104 words
The intrusion alarm system of claim 10 wherein: the anode of a first diode and the cathode of a second diode are connected to said first corner, and the anode of a third diode and the cathode of a fourth diode are connected to said second corner, and further comprising: a first bypass resistor connected across a first one of said diodes in a first arm of said bridge, and a second bypass resistor coupled across a second one of said diode in a second arm of said bridge, said first and said second arms of said bridge being opposed arms of said bridge.
Claim 13
Dependent Claim
21 words
The intrusion alarm system of claim 11 further comprising: a momentary manually operable normally open shorting contact coupled across said capacitor.
Claim 14
Dependent Claim
96 words
The intrusion alarm system of claim 11 further characterized by: a second photohead adapted to respond to ambient light conditions which may tend to initiate a false alarm, and a second pulse amplifier coupled to the output of said second photohead to provide a second output signal in response to a sudden decrease in the light incident on said second photohead, said second output signal being coupled to said input circuit of said valve, whereby the incidence of said light conditions will bias said valve in a direction tending to change the state of said valve.
Claim 15
Dependent Claim
124 words
A line voltage compensating unit comprising: a rectifier responsive to an alternating current voltage source to provide a rectified output, a capacitor, a sensing bridge having first and second opposed corners, said first corner being coupled to the output of said rectifier and said second corner being coupled to said capacitor, whereby said sensing bridge will provide an output signal at a corner other than at said first and second opposed corners whenever the output of said rectifier changes at a rapid rate and whereby a long term change in the output level of said rectifier will be coupled through said bridge to said capacitor so that the voltage of said capacitor will follow the changes in the voltage output level of said rectifier.
Claim 16
Dependent Claim
124 words
A line voltage compensating unit comprising: a rectifier responsive to an alternating current voltage source to provide a rectified output, a capacitor, a sensing bridge having first and second opposed corners, said first corner being coupled to the output of said rectifier and said second corner being coupled to said capacitor, whereby said sensing bridge will provide an output signal at a corner other than at said first and second opposed corners whenever the output of said rectifier changes at a rapid rate and whereby a long term change in the output level of said rectifier will be coupled through said bridge to said capacitor so that the voltage of said capacitor will follow the changes in the voltage output level of said rectifier.
Claim 17
Dependent Claim
84 words
The intrusion alarm system of claim 14 wherein: said rectifier unit includes a filter having a time constant sufficiently short so as to cause said rectifier output to be responsive to sudden changes in line voltage level and to proviDe sufficient ripple content in the output of said rectifier so that during a short portion of each cycle of ripple current said line voltage compensating unit provides a biasing output, said biasing output being sufficiently low so that said gate is not responsive thereto.
Claim 18
Dependent Claim
54 words
The line voltage compensating unit of claim 14 wherein said sensing bridge comprises: four arms each containing a diode, the junction of said arms serving to define said first and said second opposed corners and also to define third and fourth opposed corners, and a resistor connected between said third and fourth opposed corners.
Claim 19
Dependent Claim
48 words
The line voltage compensating unit of claim 16 wherein: the anode of a first diode and the cathode of a second diode are connected to said first corner, and the anode of a third diode and the cathode of a fourth diode are connected to said second corner.
Claim 20
Dependent Claim
69 words
The line voltage compensating unit of claim 16 further comprising: a valve having its input circuit coupled across said third and said fourth corners of said bridge, whereby a rapid change in the output voltage level from said rectifier sufficient to cause the arms of said bridge to conduct will couple biasing voltages to said valve, said biasing voltages having polarities tending to change the state of said valve.
Claim 21
Dependent Claim
74 words
The line voltage compensating unit of claim 16 further comprising: a first bypass resistor connected across a first one of said diodes in a first one of said arms of said bridge, and a second bypass resistor coupled across a second one of said diodes in a second one of said arms of said bridge, said first one and said second one of said arms of said bridge being opposed arms of said bridge.
Claim 22
Dependent Claim
22 words
The line voltage compensating unit of claim 14 further comprising: a momentary manually operable normally open shorting contact coupled across said capacitor.
Claim 23
Dependent Claim
84 words
The intrusion alarm system of claim 18 wherein: said rectifier unit includes a filter having a time constant sufficiently short so as to cause said rectifier output to be responsive to sudden changes in line voltage level and to provide sufficient ripple content in the output of said rectifier so that during a short portion of each cycle of ripple current said line voltage compensating unit provides a biasing output, said biasing output being sufficiently low so that said gate is not responsive thereto.
Claim 24
Dependent Claim
105 words
The line voltage compensating unit of claim 21 wherein: the anode of a first diode and the cathode of a second diode are connected to said first corner, and the anode of a third diode and the cathode of a fourth diode are connected to said second corner, and further comprising: a first bypass resistor connected across a first one of said diodes in a first arm of said bridge, and a second bypass resistor coupled across a second one of said diodes in a second arm of said bridge, said first and said second arms of said bridge being opposed arms of said bridge.
Claim 25
Dependent Claim
21 words
The line voltage compensating unit of claim 22 comprising: a momentary, manually operable, normally open, shorting contact coupled across said capacitor.
Claim 26
Dependent Claim
148 words
An intrusion alarm system comprising: a nondirected light source, a photohead positioned to receive light from said light source to provide an output signal having a voltage level that is a function of the amount of light incident on said photohead, and a pulse amplifier coupled to said output signal to provide an alarm initiating pulse when there is a sudden decrease in the level of light incident on said photohead, said pulse amplifier including a transistor having its input circuit coupled to said output signal from said phtohead and having its output circuit providing said alarm initiating pulse, said transistor having a first state and a second state, said transistor being normally in said first state and being forced into said second state when said output signal from said photohead Changes suddenly in response to a sudden reduction in the level of light incident on said photohead.
Claim 27
Dependent Claim
148 words
An intrusion alarm system comprising: a nondirected light source, a photohead positioned to receive light from said light source to provide an output signal having a voltage level that is a function of the amount of light incident on said photohead, and a pulse amplifier coupled to said output signal to provide an alarm initiating pulse when there is a sudden decrease in the level of light incident on said photohead, said pulse amplifier including a transistor having its input circuit coupled to said output signal from said phtohead and having its output circuit providing said alarm initiating pulse, said transistor having a first state and a second state, said transistor being normally in said first state and being forced into said second state when said output signal from said photohead Changes suddenly in response to a sudden reduction in the level of light incident on said photohead.
Claim 28
Dependent Claim
28 words
The intrusion alarm system of claim 24 wherein said first state of said transistor is a conducting state and wherein said second state is a substantially nonconducting state.
Claim 29
Dependent Claim
29 words
The intrusion alarm system of claim 25 wherein said pulse amplifier further comprises means for adjusting the level of conduction during said normal first state, thereby permitting sensitivity adjustment.
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) | 1974-09-06 | 1975-03-08 | 1975-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-06 | 1979-03-08 | 1979-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-06 | 1983-03-08 | 1983-09-07 | $7700.00 | Window Closed / Lapsed |