US3555535A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fail-safe light intrusion alarm system
Assignee: Individual
•
Filing: 1968-09-13
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Granted: 1971-01-12
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Expires: 1988-09-13
Abstract
Abstract A FAIL-SAFE ARRANGEMENT TO PREVENT EMISSION OF FALSE ALARMS IN PHOTOELECTRIC INTRUSION-DETECTION SYSTEMS IN CASES OF FAILURE OF LIGHT SOURCES. INCLUDED IS CIRCUITRY FOR RENDERING PHOTOELECTRIC INTRUSION DETECTORS INACTIVE WHEN THE LIGHT SOURCE FAILS AND AUTOMATICALLY INDICATING SUCH INACTIVITY.
Inventors
- 👤 Lance L Henriques
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:35
CPC Classifications
G; G08; G08B; G08B29/00; G08B29/02; G08B29/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |