Patent US2536261A successfully refreshed from Google Patents.
US2536261A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microphone sound filter
Assignee: RCA Corp
•
Filing: 1947-12-20
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Granted: 1951-01-02
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Expires: 1967-12-20
Abstract
No abstract record available.
Inventors
- 👤 Jr Stephen A Caldwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:48
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/08; H04R1/083; H04R1/086
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1031297A
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US1114496A
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US1188691A
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US1345717A
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US1478074A
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US1603300A
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FR674339A
Cited
US2080552A
Cited
GB453068A
Cited
US2435920A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-01-01 | 1954-07-03 | 1955-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-01-01 | 1958-07-03 | 1959-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-01-01 | 1962-07-03 | 1963-01-02 | $7700.00 | Window Closed / Lapsed |