Patent US3409529A successfully refreshed from Google Patents.
Patent US1669643A successfully refreshed from Google Patents.
US1669643A
Expired / Lapsed
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Magnetic material
Assignee: AT&T Inc
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Filing: 1926-04-17
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Granted: 1928-05-15
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Expires: 1946-04-17
Abstract
No abstract record available.
Inventors
- 👤 Andrews John Wendell
- 👤 Gillis Randall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:45
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/20; H01F1/22; H01F1/24; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12014; Y10T428/12028; Y10T428/12146; Y10T428/12493; Y10T428/12639
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1931-05-15 | 1931-11-14 | 1932-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1935-05-15 | 1935-11-14 | 1936-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1939-05-15 | 1939-11-14 | 1940-05-15 | $7700.00 | Window Closed / Lapsed |