US2093773A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making hollow valves
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1931-05-16
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Granted: 1937-09-21
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Expires: 1951-05-16
Abstract
No abstract record available.
Inventors
- 👤 Archie T Colwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:20
CPC Classifications
B; B21; B21K; B21K1/00; B21K1/20; B21K1/22; B21J; B21J5/00; B21J5/06; B21J5/08; F; F01; F01L; F01L3/00; F01L3/02; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49298; Y10T29/49307; Y10T29/49309; Y10T29/4981; Y10T29/49812
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) | 1940-09-20 | 1941-03-22 | 1941-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1944-09-20 | 1945-03-22 | 1945-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1948-09-20 | 1949-03-22 | 1949-09-21 | $7700.00 | Window Closed / Lapsed |