US3719938A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoelectric intruder detection device
Assignee: Individual
•
Filing: 1970-12-15
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Granted: 1973-03-06
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Expires: 1990-12-15
Abstract
Abstract A photoelectric intruder detection device including means for preventing false alarming in response to lightning flashes and other sources of severe electrical transients. Circuitry is provided for totally disabling the device for a predetermined time following the occurrence of such transients to permit the intruder detecting circuitry to stabilize.
Inventors
- 👤 D Perlman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:43
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/18; G08B13/181; G08B13/187
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
148 words
For use in a photoelectric intruder detection device comprising a means for transmitting a beam of radiant energy into an area to be protected from intrusion, a photoelectric transducer positioned to receive said energy as reflected or modified by objects within said beam and convert said energy into an electrical signal having an amplitude proportional to the intensity of received energy, and alarm-activating means having an input operably coupled with said signal and adapted to activate an alarm whenever said signal varies a predetermined amount from a steady-state value at a rate in excess of a predetermined value, the improvement comprising means operatively coupled to said signal for inhibiting alarm-activation by said activating means for a predetermined time interval in response to a high amplitude short duration transient change in said signal, whereby the device is rendered insensitive to bright flashes of radiant energy or intense electrical transients.
Claim 2
Dependent Claim
148 words
For use in a photoelectric intruder detection device comprising a means for transmitting a beam of radiant energy into an area to be protected from intrusion, a photoelectric transducer positioned to receive said energy as reflected or modified by objects within said beam and convert said energy into an electrical signal having an amplitude proportional to the intensity of received energy, and alarm-activating means having an input operably coupled with said signal and adapted to activate an alarm whenever said signal varies a predetermined amount from a steady-state value at a rate in excess of a predetermined value, the improvement comprising means operatively coupled to said signal for inhibiting alarm-activation by said activating means for a predetermined time interval in response to a high amplitude short duration transient change in said signal, whereby the device is rendered insensitive to bright flashes of radiant energy or intense electrical transients.
Claim 3
Dependent Claim
148 words
For use in a photoelectric intruder detection device comprising a means for transmitting a beam of radiant energy into an area to be protected from intrusion, a photoelectric transducer positioned to receive said energy as reflected or modified by objects within said beam and convert said energy into an electrical signal having an amplitude proportional to the intensity of received energy, and alarm-activating means having an input operably coupled with said signal and adapted to activate an alarm whenever said signal varies a predetermined amount from a steady-state value at a rate in excess of a predetermined value, the improvement comprising means operatively coupled to said signal for inhibiting alarm-activation by said activating means for a predetermined time interval in response to a high amplitude short duration transient change in said signal, whereby the device is rendered insensitive to bright flashes of radiant energy or intense electrical transients.
Claim 4
Dependent Claim
148 words
For use in a photoelectric intruder detection device comprising a means for transmitting a beam of radiant energy into an area to be protected from intrusion, a photoelectric transducer positioned to receive said energy as reflected or modified by objects within said beam and convert said energy into an electrical signal having an amplitude proportional to the intensity of received energy, and alarm-activating means having an input operably coupled with said signal and adapted to activate an alarm whenever said signal varies a predetermined amount from a steady-state value at a rate in excess of a predetermined value, the improvement comprising means operatively coupled to said signal for inhibiting alarm-activation by said activating means for a predetermined time interval in response to a high amplitude short duration transient change in said signal, whereby the device is rendered insensitive to bright flashes of radiant energy or intense electrical transients.
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) | 1976-03-05 | 1976-09-04 | 1977-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-05 | 1980-09-04 | 1981-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-05 | 1984-09-04 | 1985-03-06 | $7700.00 | Window Closed / Lapsed |