Patent US2921991A successfully refreshed from Google Patents.
US2921991A
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Magnetic recorder
Assignee: ACF Industries Inc
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Filing: 1956-04-27
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Granted: 1960-01-19
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Expires: 1976-04-27
Abstract
No abstract record available.
Inventors
- 👤 Fred D Sher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:33
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/008; G11B5/00813; G11B5/00817; G11B15/00; G11B15/60; G11B15/61; G11B5/004
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2710191A
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US2695785A
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GB657494A
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US2540654A
Cited
US2714010A
Cited
US2683038A
Cited
US2709597A
Cited
US2645495A
Cited
US2708693A
Cited
US2743317A
Cited
US2820688A
Cited
US2745944A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-01-18 | 1963-07-20 | 1964-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-01-18 | 1967-07-20 | 1968-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-01-18 | 1971-07-20 | 1972-01-19 | $7700.00 | Window Closed / Lapsed |