US3727207A
Expired / Lapsed
US
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Intrusion detector
Assignee: Systron Donner Corp
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Filing: 1970-06-24
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Granted: 1973-04-10
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Expires: 1990-06-24
Abstract
Abstract An optical intrusion detector which in one package employs a radar-type concept with a time interval logic circuit to measure small changes in transmitted and received signals. A plurality of measured optical pulses are transmitted to a passive reflective target, such as a tree, fence, or other dense object, and reflected back to the same source. The rate of change between the transmitted and received pulses is measured. When the rate of change in the transmitted and received signals varies from a predetermined level, an alarm is actuated. The time interval logic employed in the detector employs three flip-flop circuits and associated circuitry. The associated circuitry with a first flip-flop circuit will cause a third flip-flop circuit to be actuated to generate an alarm signal when the time interval between the pulses transmitted and received exceeds a predetermined level. A second flip-flop circuit functions in combination with the third flip-flop circuit to indicate when a decrease in the time between the transmitted and received pulses is measured to actuate an alarm.
Inventors
- 👤 D Missio
- 👤 H Wollman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:05
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/02; G01S17/04; G08; G08B; G08B13/00; G08B13/18; G08B13/181; G08B13/187
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
165 words
In an optical deteCtor system, means for transmitting optical pulses to a target, means including a photocell for receiving pulses reflected from the target and converting said pulses to electrical pulses, first bistable means adapted for switching from a first state to a second state in response to the transmitted pulses and for returning to the first state in response to the reflected pulses, second bistable means arranged for switching from a first state to a second state in response to the transmitted pulses and for returning to its first state when the first bistable means remains in its second state longer than a predetermined maximum time, third bistable means arranged for switching to an alarm state when the first bistable means remains in its second state less than a predetermined minimum time, said third bistable means also being arranged for switching to the alarm state when the second bistable means remains in its second state for a time greater than the predetermined maximum time.
Claim 2
Dependent Claim
165 words
In an optical deteCtor system, means for transmitting optical pulses to a target, means including a photocell for receiving pulses reflected from the target and converting said pulses to electrical pulses, first bistable means adapted for switching from a first state to a second state in response to the transmitted pulses and for returning to the first state in response to the reflected pulses, second bistable means arranged for switching from a first state to a second state in response to the transmitted pulses and for returning to its first state when the first bistable means remains in its second state longer than a predetermined maximum time, third bistable means arranged for switching to an alarm state when the first bistable means remains in its second state less than a predetermined minimum time, said third bistable means also being arranged for switching to the alarm state when the second bistable means remains in its second state for a time greater than the predetermined maximum time.
Claim 3
Dependent Claim
18 words
An optical detector system as in claim 1 wherein the means for transmitting optical pulses includes a laser.
Claim 4
Dependent Claim
17 words
An optical detector system as in claim 1 wherein the optical pulses are in the infrared range.
Claim 5
Dependent Claim
26 words
An optical detector system as in claim 1 together with manually operable means for switching the third bistable means from its alarm state to another state.
Claim 6
Dependent Claim
29 words
An optical detector system as in claim 1 together with means for returning the first bistable means to its first state a predetermined time after the pulses are transmitted.
Claim 7
Dependent Claim
93 words
In an intrusion detecting system, laser means for transmitting pulses of light along a path toward a fixed object, means associated with the laser means for receiving pulses reflected back along the path, means providing an electrical signal corresponding to the interval between successive ones of the transmitted and received pulses, said signal having a normal value corresponding to the transit time of pulses reflected from the fixed object, and means responsive to the signal for actuating an alarm if said signal varies from its normal value by more than a predetermined amount.
Claim 8
Dependent Claim
93 words
In an intrusion detecting system, laser means for transmitting pulses of light along a path toward a fixed object, means associated with the laser means for receiving pulses reflected back along the path, means providing an electrical signal corresponding to the interval between successive ones of the transmitted and received pulses, said signal having a normal value corresponding to the transit time of pulses reflected from the fixed object, and means responsive to the signal for actuating an alarm if said signal varies from its normal value by more than a predetermined amount.
Claim 9
Dependent Claim
94 words
In a method for detecting interruptions in a pulsed beam and actuating an alarm when the beam is interrupted, the steps of transmitting a plurality of optical pulses along a path from a source toward a fixed target, receiving pulses reflected back along the path, determining the time interval between successive ones of the transmitted and reflected pulses, said time interval having a normal value corresponding to the transit time of pulses reflected by the fixed object, and actuating an alarm if the time interval varies from its normal value by a predetermined amount.
Claim 10
Dependent Claim
94 words
In a method for detecting interruptions in a pulsed beam and actuating an alarm when the beam is interrupted, the steps of transmitting a plurality of optical pulses along a path from a source toward a fixed target, receiving pulses reflected back along the path, determining the time interval between successive ones of the transmitted and reflected pulses, said time interval having a normal value corresponding to the transit time of pulses reflected by the fixed object, and actuating an alarm if the time interval varies from its normal value by a predetermined amount.
Claim 11
Dependent Claim
166 words
In an intrusion detecting system, laser means for transmitting pulses of light along a path toward a fixed object, means associated with the laser means for receiving pulses reflected back along the path, means providing an electrical signal having a duration corresponding to the time interval between successive ones of the transmitted and received pulses, said signal having a normal duration corresponding to the transit time of pulses reflected from the fixed object, bistable means arranged for switching from a first state to a second state in response to each transmitted pulse and for returning to the first state when the duration of the signal exceeds a predetermined maximum, and additional bistable means arranged for switching to an alarm state when the first named bistable means remains in its second state for a period of time greater than the predetermined maximum, said additional bistable means also being arranged for switching to the alarm state when the duration of the signal is less than a predetermined minimum.
Claim 12
Dependent Claim
166 words
In an intrusion detecting system, laser means for transmitting pulses of light along a path toward a fixed object, means associated with the laser means for receiving pulses reflected back along the path, means providing an electrical signal having a duration corresponding to the time interval between successive ones of the transmitted and received pulses, said signal having a normal duration corresponding to the transit time of pulses reflected from the fixed object, bistable means arranged for switching from a first state to a second state in response to each transmitted pulse and for returning to the first state when the duration of the signal exceeds a predetermined maximum, and additional bistable means arranged for switching to an alarm state when the first named bistable means remains in its second state for a period of time greater than the predetermined maximum, said additional bistable means also being arranged for switching to the alarm state when the duration of the signal is less than a predetermined minimum.
Claim 13
Dependent Claim
143 words
In a method for detecting interruptions in a pulsed beam and actuating an alarm when the beam is interrupted, the steps of transmitting a plurality of optical pulses along a path from a source toward a fixed target, receiving pulses reflected back along the path, determining the tiMe interval between successive ones of the transmitted and reflected pulses, said time interval having a normal value corresponding to the transit time of pulses reflected by the fixed object, switching a bistable element from a first state to a second state in response to each transmitted pulse, returning the bistable element to the first state if the time interval determined exceeds a predetermined maximum, and switching an additional bistable element to an alarm state if the first named bistable element remains in its second state for a period of time greater than the predetermined maximum.
Claim 14
Dependent Claim
143 words
In a method for detecting interruptions in a pulsed beam and actuating an alarm when the beam is interrupted, the steps of transmitting a plurality of optical pulses along a path from a source toward a fixed target, receiving pulses reflected back along the path, determining the tiMe interval between successive ones of the transmitted and reflected pulses, said time interval having a normal value corresponding to the transit time of pulses reflected by the fixed object, switching a bistable element from a first state to a second state in response to each transmitted pulse, returning the bistable element to the first state if the time interval determined exceeds a predetermined maximum, and switching an additional bistable element to an alarm state if the first named bistable element remains in its second state for a period of time greater than the predetermined maximum.
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) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |