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Patent US2577973A successfully refreshed from Google Patents.
US2577973A
Expired / Lapsed
US
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Fire warning device
Assignee: PHOTOSWITCH Inc
•
Filing: 1948-07-22
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Granted: 1951-12-11
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Expires: 1968-07-22
Abstract
No abstract record available.
Inventors
- 👤 Donald J Macdougall
- 👤 Phillip J Cade
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:36
CPC Classifications
G; G08; G08B; G08B17/00; G08B17/12
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1939435A
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US2243591A
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US2355664A
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US2455351A
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US2413218A
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US2426734A
Cited
US2433559A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-12-10 | 1955-06-11 | 1955-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-12-10 | 1959-06-11 | 1959-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-12-10 | 1963-06-11 | 1963-12-11 | $7700.00 | Window Closed / Lapsed |