Patent US2660622A successfully refreshed from Google Patents.
US2660622A
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Magnetic telegraphophone transducer
Assignee: Engineering Research Associates Inc
•
Filing: 1949-09-27
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Granted: 1953-11-24
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Expires: 1969-09-27
Abstract
No abstract record available.
Inventors
- 👤 William J Field
- 👤 Robert L Perkins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:58
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/147
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US2431540A
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US2469444A
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US2456767A
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US2459299A
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US2549771A
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US2555110A
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US2536272A
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US2565191A
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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) | 1956-11-23 | 1957-05-25 | 1957-11-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-11-23 | 1961-05-25 | 1961-11-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-11-23 | 1965-05-25 | 1965-11-24 | $7700.00 | Window Closed / Lapsed |