US1904261A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Indirectly heated cathode
Assignee: AT&T Inc
•
Filing: 1931-03-16
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Granted: 1933-04-18
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Expires: 1951-03-16
Abstract
No abstract record available.
Inventors
- 👤 Bedford Leslie Herbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 19:26
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/20
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) | 1936-04-17 | 1936-10-17 | 1937-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1940-04-17 | 1940-10-17 | 1941-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1944-04-17 | 1944-10-17 | 1945-04-18 | $7700.00 | Window Closed / Lapsed |