US2021572A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making piston rings
Assignee: Wilkening Manufacturing Co
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Filing: 1933-12-26
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Granted: 1935-11-19
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Expires: 1953-12-26
Abstract
No abstract record available.
Inventors
- 👤 Wuerfel William
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:23
CPC Classifications
B; B23; B23P; B23P15/00; B23P15/08; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49274; Y10T29/49284
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) | 1938-11-18 | 1939-05-20 | 1939-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1942-11-18 | 1943-05-20 | 1943-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1946-11-18 | 1947-05-20 | 1947-11-19 | $7700.00 | Window Closed / Lapsed |