Patent US2441840A successfully refreshed from Google Patents.
US2441840A
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US
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Electronic amplifier control circuit
Assignee: Dictaphone Corp
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Filing: 1944-09-23
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Granted: 1948-05-18
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Expires: 1964-09-23
Abstract
No abstract record available.
Inventors
- 👤 Lucius P Petruschell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:46
CPC Classifications
H; H04; H04M; H04M1/00; H04M1/64; H04M1/65; H04M1/6515; H03; H03G; H03G3/00; H03G3/20; H03G3/22; H04M1/02; H04M1/21; H04M1/215
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2137401A
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US2219729A
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US2250559A
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US2244695A
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US2332536A
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US2278828A
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US2319665A
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US2340159A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-05-18 | 1951-11-17 | 1952-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-05-18 | 1955-11-17 | 1956-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-05-18 | 1959-11-17 | 1960-05-18 | $7700.00 | Window Closed / Lapsed |