Patent US2521880A successfully refreshed from Google Patents.
US2521880A
Expired / Lapsed
US
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Control system for high-frequency induction heating apparatus
Assignee: Sunbeam Corp
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Filing: 1946-09-25
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Granted: 1950-09-12
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Expires: 1966-09-25
Abstract
No abstract record available.
Inventors
- 👤 Herbert F Storm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:39
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/02; H05B6/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US2231457A
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US2147689A
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US2400472A
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US2416172A
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US2391085A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-09-11 | 1954-03-13 | 1954-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-09-11 | 1958-03-13 | 1958-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-09-11 | 1962-03-13 | 1962-09-12 | $7700.00 | Window Closed / Lapsed |