Patent US2429470A successfully refreshed from Google Patents.
US2429470A
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US
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Loud-speaker with pressure-equalized chamber system enclosing flux gap
Assignee: JENSEN Manufacturing Co
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Filing: 1942-09-03
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Granted: 1947-10-21
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Expires: 1962-09-03
Abstract
No abstract record available.
Inventors
- 👤 Hugh S Knowles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:26
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/22; H04R1/28; H04R1/2869; H04R1/2873; H04R1/30; H04R9/00; H04R9/02; H04R9/022; H04R9/025
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US1964606A
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US2041157A
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US2037187A
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US2084944A
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US2261110A
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US2261111A
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US2086649A
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US2095373A
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US2252846A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-10-20 | 1951-04-21 | 1951-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-10-20 | 1955-04-21 | 1955-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-10-20 | 1959-04-21 | 1959-10-21 | $7700.00 | Window Closed / Lapsed |