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Patent US1221981A successfully refreshed from Google Patents.
US1221981A
Expired / Lapsed
US
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Alternating-current rectifier.
Assignee: NEW JERSEY PATENT CO
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Filing: 1911-12-30
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Granted: 1917-04-10
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Expires: 1931-12-30
Abstract
No abstract record available.
Inventors
- 👤 Thomas A Edison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:00
CPC Classifications
H; H01; H01H; H01H50/00; H01H50/64; H01H50/74; H01H50/76
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) | 1920-04-09 | 1920-10-09 | 1921-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1924-04-09 | 1924-10-09 | 1925-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1928-04-09 | 1928-10-09 | 1929-04-10 | $7700.00 | Window Closed / Lapsed |