US2638510A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Duplex loud-speaker
Assignee: CAESAR DAVID ZEITOUNI
•
Filing: 1949-01-06
•
Granted: 1953-05-12
•
Expires: 1969-01-06
Abstract
No abstract record available.
Inventors
- 👤 Brami Joseph
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:36
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/22; H04R1/30
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1759614A
Cited
US1907723A
Cited
US2007747A
Cited
US2295483A
Cited
GB442900A
Cited
US2077170A
Cited
US2214591A
Cited
US2167625A
Cited
US2301459A
Cited
US2426948A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-05-11 | 1956-11-10 | 1957-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-05-11 | 1960-11-10 | 1961-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-05-11 | 1964-11-10 | 1965-05-12 | $7700.00 | Window Closed / Lapsed |