Patent US2771901A successfully refreshed from Google Patents.
US2771901A
Expired / Lapsed
US
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Non-return valves
Assignee: Normalair Ltd
•
Filing: 1953-04-13
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Granted: 1956-11-27
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Expires: 1973-04-13
Abstract
No abstract record available.
Inventors
- 👤 Speck Eric Hardy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 21:47
CPC Classifications
F; F16; F16K; F16K15/00; F16K15/02; F16K15/03; Y; Y10; Y10T; Y10T137/00; Y10T137/5109; Y10T137/5153; Y10T137/7722; Y10T137/7837; Y10T137/7898; Y10T137/7903
Claims Analysis
Total Claims: 0
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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) | 1959-11-27 | 1960-05-28 | 1960-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-11-27 | 1964-05-28 | 1964-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-11-27 | 1968-05-28 | 1968-11-27 | $7700.00 | Window Closed / Lapsed |