Patent US2973504A successfully refreshed from Google Patents.
US2973504A
Expired / Lapsed
US
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Sonic echo system
Assignee: Individual
•
Filing: 1951-03-26
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Granted: 1961-02-28
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Expires: 1971-03-26
Abstract
No abstract record available.
Inventors
- 👤 Robert J Bobber
- 👤 Charles L Darner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:34
CPC Classifications
G; G01; G01S; G01S1/00; G01S1/72; Y; Y10; Y10S; Y10S367/00; Y10S367/903
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1674683A
Cited
US1732427A
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US1899748A
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US2407242A
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US2053364A
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US2435253A
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US2295527A
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US2453521A
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US2433991A
Cited
US2702379A
Cited
US2585173A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-02-28 | 1964-08-29 | 1965-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-02-28 | 1968-08-29 | 1969-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-02-28 | 1972-08-29 | 1973-02-28 | $7700.00 | Window Closed / Lapsed |