US2551871A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thermionic cathode construction
Assignee: Superior Tube Co
•
Filing: 1949-02-11
•
Granted: 1951-05-08
•
Expires: 1969-02-11
Abstract
No abstract record available.
Inventors
- 👤 Jr Thomas H Briggs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:35
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/88; H01J1/94; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49826; Y10T29/49908; Y10T29/49938; Y10T29/4994
Claims Analysis
Total Claims: 0
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-05-07 | 1954-11-06 | 1955-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-05-07 | 1958-11-06 | 1959-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-05-07 | 1962-11-06 | 1963-05-08 | $7700.00 | Window Closed / Lapsed |