US2533516A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hearing aid microphone
Assignee: Zenith Electronics LLC
•
Filing: 1948-10-29
•
Granted: 1950-12-12
•
Expires: 1968-10-29
Abstract
No abstract record available.
Inventors
- 👤 Walter A Schwalm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:32
CPC Classifications
H; H04; H04R; H04R25/00; H04R25/48
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1026231A
Cited
US1209291A
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US2304339A
Cited
US2351400A
Cited
US2358099A
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US2417153A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-12-11 | 1954-06-12 | 1954-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-12-11 | 1958-06-12 | 1958-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-12-11 | 1962-06-12 | 1962-12-12 | $7700.00 | Window Closed / Lapsed |