US3281817A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Intruder detection
Assignee: Specialties Development Corp
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Filing: 1964-07-02
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Granted: 1966-10-25
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Expires: 1984-07-02
Abstract
No abstract record available.
Inventors
- 👤 Andrew M Archer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:04
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/18; G08B13/189; G08B13/1895
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
160 words
AN AMBIENT LIGHT RESPONSIVE SYSTEM FOR DETECTING THE PRESENCE OF AN INTRUDER WITHIN ANY PORTION OF AN AREA UNDER SURVEILLANCE COMPRISING AN ELECTRICAL ELEMENT RESPONSIVE TO LIGHT TO CHANGE ELECTRICAL VALUES THEREOF AND HAVING A SURFACE EXPOSED TO AND RESPONSIVE TO CHANGES IN AMBIENT LIGHT REFLECTED FROM SAID AREA WHICH REFLECTED LIGHT IS CHANGED IN INTENSITY BY THE PRESENCE OF AN INTRUDER THAT REFLECTS LIGHT TO A DIFFERENT DEGREE THAN THE PORTION OF THE AREA OBSCURED BY THE INTRUDER, MEANS FOR ALTERNATELY EXPOSING TWO PORTIONS OF THE SURFACE OF SAID ELEMENT TO AN EQUAL HIGHER AND LOWER LIGHT INTENSITY, REACTANCE MEANS, A POWER SOURCE FOR OPERATING SAID ALTERNATELY EXPOSING MEANS AND FOR PASSING A CURRENT THROUGH SAID REACTANCE MEANS WHICH REVERSES DIRECTION IN SYNCHRONISM WITH SAID ALTERNATELY EXPOSING MEANS, SAID ELEMENT BEING CONNECTED TO VARY THE CURRENT FLOWING THROUGH SAID REACTANCE MEANS IN RESPONSE TO THE LIGHT INTENSITY ON SAID SURFACE, WHEREBY SAID REACTANCE MEANS DISCHARGES TO PRODUCE AN OUTPUT
Claim 2
Dependent Claim
160 words
AN AMBIENT LIGHT RESPONSIVE SYSTEM FOR DETECTING THE PRESENCE OF AN INTRUDER WITHIN ANY PORTION OF AN AREA UNDER SURVEILLANCE COMPRISING AN ELECTRICAL ELEMENT RESPONSIVE TO LIGHT TO CHANGE ELECTRICAL VALUES THEREOF AND HAVING A SURFACE EXPOSED TO AND RESPONSIVE TO CHANGES IN AMBIENT LIGHT REFLECTED FROM SAID AREA WHICH REFLECTED LIGHT IS CHANGED IN INTENSITY BY THE PRESENCE OF AN INTRUDER THAT REFLECTS LIGHT TO A DIFFERENT DEGREE THAN THE PORTION OF THE AREA OBSCURED BY THE INTRUDER, MEANS FOR ALTERNATELY EXPOSING TWO PORTIONS OF THE SURFACE OF SAID ELEMENT TO AN EQUAL HIGHER AND LOWER LIGHT INTENSITY, REACTANCE MEANS, A POWER SOURCE FOR OPERATING SAID ALTERNATELY EXPOSING MEANS AND FOR PASSING A CURRENT THROUGH SAID REACTANCE MEANS WHICH REVERSES DIRECTION IN SYNCHRONISM WITH SAID ALTERNATELY EXPOSING MEANS, SAID ELEMENT BEING CONNECTED TO VARY THE CURRENT FLOWING THROUGH SAID REACTANCE MEANS IN RESPONSE TO THE LIGHT INTENSITY ON SAID SURFACE, WHEREBY SAID REACTANCE MEANS DISCHARGES TO PRODUCE AN OUTPUT
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) | 1969-10-24 | 1970-04-25 | 1970-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-10-24 | 1974-04-25 | 1974-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-10-24 | 1978-04-25 | 1978-10-25 | $7700.00 | Window Closed / Lapsed |