US3566385A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fire detecting apparatus sensitive to refraction
Assignee: NAT RES DEV
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Filing: 1968-04-22
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Granted: 1971-02-23
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Expires: 1988-04-22
Abstract
Abstract FIRE DETECTING APPARATUS COMPRISES A LASER, A PHOTOCELL WHICH ARE SPACED FROM EACH OTHER, THE PHOTOCELL BEING RESPONSIVE TO A STATE OF INCIDENCE OF THE LIGHT BEAM THEREON AND AN ALARAM AND/OR FIRE CONTROL APPARATUS FOR ACTIVATION IN RESPONSE TO A STATE OF NON-INCIDENCE OF THE BEAM ON THE DETECTOR. THE LASER AND PHOTOCELL ARE SO ARRANGED, E.G. SO THE LIGHT BEAM TAKES A PATH OF ZIG-ZAG CONFIGURATION, THE REFRACTION OF THE BEAM DURING ITS PASSAGE THROUGH THE SPACE IN THE PRESENCE OF FIRE PRODUCES THE STATE OF NONINCIDENCE OF THE LIGHT BEAM.
Inventors
- 👤 Dennis Illingworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:02
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/41; G08; G08B; G08B17/00; G08B17/10; G08B17/103
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) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |