US2529228A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Damper for hearing aids
Assignee: Zenith Electronics LLC
•
Filing: 1947-04-26
•
Granted: 1950-11-07
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Expires: 1967-04-26
Abstract
No abstract record available.
Inventors
- 👤 Walter A Schwalm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:41
CPC Classifications
H; H04; H04R; H04R17/00; H04R11/00; H04R11/06; H04R25/00
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) | 1953-11-06 | 1954-05-08 | 1954-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-11-06 | 1958-05-08 | 1958-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-11-06 | 1962-05-08 | 1962-11-07 | $7700.00 | Window Closed / Lapsed |