Patent US2889401A successfully refreshed from Google Patents.
US2889401A
Expired / Lapsed
US
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Intercommunication unit
Assignee: MID WEST COIL AND TRANSFORMER
•
Filing: 1956-09-12
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Granted: 1959-06-02
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Expires: 1976-09-12
Abstract
No abstract record available.
Inventors
- 👤 Finkbeiner Ernest
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:21
CPC Classifications
H; H04; H04M; H04M9/00; H04M9/001
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1760920A
Cited
US2133384A
Cited
US2571514A
Cited
US2659772A
Cited
US2691073A
Cited
US2775652A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-06-01 | 1962-12-01 | 1963-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-06-01 | 1966-12-01 | 1967-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-06-01 | 1970-12-01 | 1971-06-02 | $7700.00 | Window Closed / Lapsed |