US2638504A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-frequency electrical device having gastight envelopes
Assignee: EMI Ltd
•
Filing: 1946-10-05
•
Granted: 1953-05-12
•
Expires: 1966-10-05
Abstract
No abstract record available.
Inventors
- 👤 Pearce Albert Frederick
- 👤 Barford Norman Charles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:30
CPC Classifications
H; H01; H01P; H01P7/00; H01P7/06; H01P1/00; H01P1/08; H01J; H01J25/00; H01J31/00; H01P5/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2090033A
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US2155508A
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US2454761A
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US2403302A
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US2403303A
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US2419049A
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US2473724A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-05-11 | 1956-11-10 | 1957-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-05-11 | 1960-11-10 | 1961-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-05-11 | 1964-11-10 | 1965-05-12 | $7700.00 | Window Closed / Lapsed |