US3381773A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic resistance
Assignee: US Philips Corp
•
Filing: 1967-02-21
•
Granted: 1968-05-07
•
Expires: 1987-02-21
Abstract
No abstract record available.
Inventors
- 👤 Schenkel Gerrit
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:47
CPC Classifications
H; H04; H04R; H04R1/00; H04R1/20; H04R1/22
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2152205A
Cited
US2576610A
Cited
US3115207A
Cited
US3293379A
Cited
US3163256A
Cited
US3163255A
Cited
US3270834A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-05-07 | 1971-11-06 | 1972-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-05-07 | 1975-11-06 | 1976-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-05-07 | 1979-11-06 | 1980-05-07 | $7700.00 | Window Closed / Lapsed |