US2528498A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hearing aid amplifier
Assignee: Sonotone Corp
•
Filing: 1947-10-10
•
Granted: 1950-11-07
•
Expires: 1967-10-10
Abstract
No abstract record available.
Inventors
- 👤 Joseph W Crownover
- 👤 Harry A Pearson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:13
CPC Classifications
H; H03; H03F; H03F1/00; H03F1/34; H03F1/36; H04; H04R; 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 |