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US2638896A
Expired / Lapsed
US
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Spring structure
Assignee: Individual
•
Filing: 1948-07-10
•
Granted: 1953-05-19
•
Expires: 1968-07-10
Abstract
No abstract record available.
Inventors
- 👤 John T Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:38
CPC Classifications
A; A61; A61F; A61F6/00; A61F6/06; A61F6/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US178458A
Cited
US202037A
Cited
DE557914C
Cited
US647003A
Cited
US2463356A
Cited
US2538478A
Cited
US2529363A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-05-18 | 1956-11-17 | 1957-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-05-18 | 1960-11-17 | 1961-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-05-18 | 1964-11-17 | 1965-05-19 | $7700.00 | Window Closed / Lapsed |