Patent US1987328A successfully refreshed from Google Patents.
US1987328A
Expired / Lapsed
US
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Vapor filled thermionic tube
Assignee: Heintz & Kaufman Ltd
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Filing: 1933-05-27
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Granted: 1935-01-08
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Expires: 1953-05-27
Abstract
No abstract record available.
Inventors
- 👤 William W Eitel
- 👤 Mccullough Jack
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:50
CPC Classifications
H; H01; H01J; H01J17/00; H01J17/50; H01J17/52; H01J17/54; H01J17/56
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) | 1938-01-07 | 1938-07-09 | 1939-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1942-01-07 | 1942-07-09 | 1943-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1946-01-07 | 1946-07-09 | 1947-01-08 | $7700.00 | Window Closed / Lapsed |