US2904640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combination ear-mounted microphone and receiver instrument
Assignee: Ohio State University Research Foundation
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Filing: 1957-07-30
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Granted: 1959-09-15
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Expires: 1977-07-30
Abstract
No abstract record available.
Inventors
- 👤 John J Dreher
- 👤 Lewis J Schwartzkopf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:24
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/02; H04M1/04; H04M1/05; H04R; H04R1/00; H04R1/10; H04R1/1016; H04R1/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1962-09-14 | 1963-03-16 | 1963-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-09-14 | 1967-03-16 | 1967-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-09-14 | 1971-03-16 | 1971-09-15 | $7700.00 | Window Closed / Lapsed |