Patent US3564524A successfully refreshed from Google Patents.
US3564524A
Expired / Lapsed
US
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Fire alarm system having a diode coupled checking circuit means
Assignee: Cerberus AG
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Filing: 1967-05-04
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Granted: 1971-02-16
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Expires: 1987-05-04
Abstract
Abstract A FIRE ALARM SYSTEM INCLUDING A PLURALITY OF FIRE ALARMS ARRANGED IN GROUPS. ALARM-SIMULTING CONDITIONS ARE PRODUCED IN EACH FIRE ALARM BY AN ELECTRIC TEST SIGNAL, THE RESPONSE OF EACH FIRE ALARM BEING SENT TO AN EVALUATION DEVICE AT A CENTRAL SIGNAL STATION THROUGH A LOGIC CIRCUIT COUPLING THE FIRE ALARMS TOGETHER.
Inventors
- 👤 Beat Walthard
- 👤 Andreas Scheidweiler
- 👤 Max Kuhn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:33
CPC Classifications
G; G08; G08B; G08B29/00; G08B29/12; G08B29/14; G08B29/145
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) | 1974-02-15 | 1974-08-17 | 1975-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-15 | 1978-08-17 | 1979-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-15 | 1982-08-17 | 1983-02-16 | $7700.00 | Window Closed / Lapsed |