Patent US2442791A successfully refreshed from Google Patents.
US2442791A
Expired / Lapsed
US
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Acoustic device
Assignee: AT&T Inc
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Filing: 1945-09-07
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Granted: 1948-06-08
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Expires: 1965-09-07
Abstract
No abstract record available.
Inventors
- 👤 Edward C Wente
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:38
CPC Classifications
H; H04; H04R; H04R7/00; H04R7/16; H04R7/18; H04R7/20; H04R2307/00; H04R2307/207
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1664988A
Cited
US1014240A
Cited
US1757107A
Cited
GB321430A
Cited
US1775294A
Cited
US1962374A
Cited
US2014297A
Cited
US2109955A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-06-08 | 1951-12-08 | 1952-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-06-08 | 1955-12-08 | 1956-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-06-08 | 1959-12-08 | 1960-06-08 | $7700.00 | Window Closed / Lapsed |