Patent US2821379A successfully refreshed from Google Patents.
US2821379A
Expired / Lapsed
US
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Torque spring
Assignee: MECHANICAL SPRING FABRICATORS
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Filing: 1954-03-10
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Granted: 1958-01-28
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Expires: 1974-03-10
Abstract
No abstract record available.
Inventors
- 👤 Wilfred T Donkin
- 👤 Frank G Sabik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:02
CPC Classifications
F; F16; F16F; F16F1/00; F16F1/02; F16F1/04; F16F1/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US155129A
Cited
US1178862A
Cited
US1365701A
Cited
US1589467A
Cited
US1486381A
Cited
US2241969A
Cited
US2675578A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-01-27 | 1961-07-29 | 1962-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-01-27 | 1965-07-29 | 1966-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-01-27 | 1969-07-29 | 1970-01-28 | $7700.00 | Window Closed / Lapsed |