Patent US1833025A successfully refreshed from Google Patents.
US1833025A
Expired / Lapsed
US
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Method for hardening the inner surface of cylindrical metal bodies
Assignee: United States Pipe and Foundry Co LLC
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Filing: 1929-07-31
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Granted: 1931-11-24
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Expires: 1949-07-31
Abstract
No abstract record available.
Inventors
- 👤 Frederick C Langenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:11
CPC Classifications
B; B24; B24B; B24B31/00; B24B31/006; C; C21; C21D; C21D7/00; C21D7/02; C21D7/04; C21D7/06; Y; Y10; Y10S; Y10S29/00; Y10S29/049; Y10T; Y10T29/00; Y10T29/47
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) | 1934-11-23 | 1935-05-25 | 1935-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1938-11-23 | 1939-05-25 | 1939-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1942-11-23 | 1943-05-25 | 1943-11-24 | $7700.00 | Window Closed / Lapsed |