US2627931A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Means for improving frequency response of sound systems
Assignee: Stromberg Carlson Corp
•
Filing: 1949-12-03
•
Granted: 1953-02-10
•
Expires: 1969-12-03
Abstract
No abstract record available.
Inventors
- 👤 Edmund T Flewelling
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 01:18
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/22; H04R1/28; H04R1/2807; H04R1/2838; H04R1/2842; H04R1/2869; H04R1/2876; H04R1/288; H04R3/00; H04R3/12
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US782582A
Cited
US1953135A
Cited
US1912454A
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US1932343A
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GB447749A
Cited
US2097289A
Cited
US2143175A
Cited
US2229702A
Cited
US2179840A
Cited
US2205804A
Cited
US2313098A
Cited
US2514267A
Cited
US2491982A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-02-10 | 1956-08-11 | 1957-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-02-10 | 1960-08-11 | 1961-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-02-10 | 1964-08-11 | 1965-02-10 | $7700.00 | Window Closed / Lapsed |