Patent US2539837A successfully refreshed from Google Patents.
US2539837A
Expired / Lapsed
US
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Rotating magnetic reproducer
Assignee: Indiana Steel Products Co
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Filing: 1947-01-06
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Granted: 1951-01-30
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Expires: 1967-01-06
Abstract
No abstract record available.
Inventors
- 👤 Hugh A Howell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:51
CPC Classifications
G; G11; G11B; G11B27/00; G11B27/005; G11B15/00; G11B15/18; G11B15/1808; G11B5/00; G11B5/48; G11B5/52; G11B5/53
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-01-29 | 1954-07-31 | 1955-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-01-29 | 1958-07-31 | 1959-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-01-29 | 1962-07-31 | 1963-01-30 | $7700.00 | Window Closed / Lapsed |