US2578452A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mechanical filter
Assignee: RCA Corp
•
Filing: 1949-05-14
•
Granted: 1951-12-11
•
Expires: 1969-05-14
Abstract
No abstract record available.
Inventors
- 👤 Walter Van B Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:11
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/48; H03H9/50; H03H3/00; H03H3/007
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1666681A
Cited
US1654123A
Cited
GB291521A
Cited
US1784830A
Cited
US1852795A
Cited
US2063948A
Cited
US2091250A
Cited
US2495740A
Cited
US2501488A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-12-10 | 1955-06-11 | 1955-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-12-10 | 1959-06-11 | 1959-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-12-10 | 1963-06-11 | 1963-12-11 | $7700.00 | Window Closed / Lapsed |