US2552878A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Second order differential microphone
Assignee: Bosch Security Systems Inc
•
Filing: 1947-09-24
•
Granted: 1951-05-15
•
Expires: 1967-09-24
Abstract
No abstract record available.
Inventors
- 👤 Alpha M Wiggins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:10
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/32; H04R1/34; H04R1/38; H04R1/40; H04R1/406
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1753137A
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US2164157A
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US2198424A
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US2184247A
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US2196342A
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US2233886A
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US2293258A
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US2295376A
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US2476396A
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US2301744A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-05-14 | 1954-11-13 | 1955-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-05-14 | 1958-11-13 | 1959-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-05-14 | 1962-11-13 | 1963-05-15 | $7700.00 | Window Closed / Lapsed |