US2667621A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Torsional filter
Assignee: RCA Corp
•
Filing: 1950-06-07
•
Granted: 1954-01-26
•
Expires: 1970-06-07
Abstract
No abstract record available.
Inventors
- 👤 Jr Leslie L Burns
- 👤 Walter Van B Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:23
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/62
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-01-25 | 1957-07-27 | 1958-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-01-25 | 1961-07-27 | 1962-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-01-25 | 1965-07-27 | 1966-01-26 | $7700.00 | Window Closed / Lapsed |