Patent US2257795A successfully refreshed from Google Patents.
US2257795A
Expired / Lapsed
US
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Electron discharge apparatus and circuits
Assignee: AT&T Inc
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Filing: 1939-05-27
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Granted: 1941-10-07
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Expires: 1959-05-27
Abstract
No abstract record available.
Inventors
- 👤 Gray Frank
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:58
CPC Classifications
H; H03; H03D; H03D7/00; H03D7/22; H01; H01J; H01J25/00; H01J25/78; H01J43/00; H01J43/02; H03B; H03B13/00; H03C; H03C1/00; H03C1/32; H04; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/30
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) | 1944-10-06 | 1945-04-07 | 1945-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-10-06 | 1949-04-07 | 1949-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-10-06 | 1953-04-07 | 1953-10-07 | $7700.00 | Window Closed / Lapsed |