Patent US2531231A successfully refreshed from Google Patents.
US2531231A
Expired / Lapsed
US
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Variable permeability tuning device
Assignee: RCA Corp
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Filing: 1945-12-04
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Granted: 1950-11-21
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Expires: 1965-12-04
Abstract
No abstract record available.
Inventors
- 👤 Jr John W Million
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:05
CPC Classifications
H; H01; H01F; H01F21/00; H01F21/02; H01F21/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2210303A
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US2173084A
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US2247655A
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US2259003A
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US2255680A
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US2338134A
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US2423824A
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US2403349A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-11-20 | 1954-05-22 | 1954-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-11-20 | 1958-05-22 | 1958-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-11-20 | 1962-05-22 | 1962-11-21 | $7700.00 | Window Closed / Lapsed |