Patent US2808468A successfully refreshed from Google Patents.
US2808468A
Expired / Lapsed
US
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Magnetic insert earphone and inserts therefor
Assignee: Sonotone Corp
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Filing: 1952-02-07
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Granted: 1957-10-01
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Expires: 1972-02-07
Abstract
No abstract record available.
Inventors
- 👤 William F Knauert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 12:17
CPC Classifications
H; H04; H04R; H04R25/00; H04R25/65; H04R25/652; H04R11/00; H04R11/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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GB289719A
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US1893474A
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US2261979A
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US2284462A
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US2325590A
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US2344023A
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US2390243A
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US2493734A
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US2506490A
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US2521414A
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US2582287A
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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) | 1960-09-30 | 1961-04-01 | 1961-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-09-30 | 1965-04-01 | 1965-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-09-30 | 1969-04-01 | 1969-10-01 | $7700.00 | Window Closed / Lapsed |