Patent US2013792A successfully refreshed from Google Patents.
US2013792A
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US
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Seamless diaphragm
Assignee: Telefunken AG
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Filing: 1934-01-09
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Granted: 1935-09-10
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Expires: 1954-01-09
Abstract
No abstract record available.
Inventors
- 👤 Schafer Erich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:45
CPC Classifications
H; H04; H04R; H04R7/00; H04R7/02; H04R7/12; H04R7/14
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) | 1938-09-09 | 1939-03-11 | 1939-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1942-09-09 | 1943-03-11 | 1943-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1946-09-09 | 1947-03-11 | 1947-09-10 | $7700.00 | Window Closed / Lapsed |