Patent US2137221A successfully refreshed from Google Patents.
US2137221A
Expired / Lapsed
US
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Motor protection device
Assignee: Westinghouse Air Brake Co
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Filing: 1937-01-13
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Granted: 1938-11-22
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Expires: 1957-01-13
Abstract
No abstract record available.
Inventors
- 👤 Burton S Aikman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:42
CPC Classifications
H; H02; H02H; H02H5/00; H02H5/08; H02H5/086
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) | 1941-11-21 | 1942-05-23 | 1942-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1945-11-21 | 1946-05-23 | 1946-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1949-11-21 | 1950-05-23 | 1950-11-22 | $7700.00 | Window Closed / Lapsed |