US2982821A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sound reproduction system
Assignee: US Philips Corp
•
Filing: 1955-11-21
•
Granted: 1961-05-02
•
Expires: 1975-11-21
Abstract
No abstract record available.
Inventors
- 👤 Kleis Derk
- 👤 Vermeulen Roelof
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:57
CPC Classifications
H; H04; H04S; H04S3/00; G; G10; G10K; G10K15/00; G10K15/08; G10K15/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1358053A
Cited
US2017153A
Cited
US2327956A
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US2419894A
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US2778874A
Cited
US2819348A
Cited
US2768237A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-05-01 | 1964-10-31 | 1965-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-05-01 | 1968-10-31 | 1969-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-05-01 | 1972-10-31 | 1973-05-02 | $7700.00 | Window Closed / Lapsed |