Patent US1733718A successfully refreshed from Google Patents.
US1733718A
Expired / Lapsed
US
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Apparatus for concentrating audible signals by interference
Assignee: Individual
•
Filing: 1925-07-24
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Granted: 1929-10-29
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Expires: 1945-07-24
Abstract
No abstract record available.
Inventors
- 👤 Blondel Andre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:02
CPC Classifications
H; H04; H04B; H04B11/00; G; G01; G01S; G01S1/00; G01S1/72
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1932-10-28 | 1933-04-29 | 1933-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1936-10-28 | 1937-04-29 | 1937-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1940-10-28 | 1941-04-29 | 1941-10-29 | $7700.00 | Window Closed / Lapsed |