US2721311A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High voltage low pass filters
Assignee: Sprague Electric Co
•
Filing: 1950-03-07
•
Granted: 1955-10-18
•
Expires: 1970-03-07
Abstract
No abstract record available.
Inventors
- 👤 Paul H Netherwood
- 👤 William M Allison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:35
CPC Classifications
H; H01; H01G; H01G4/00; H01G4/32; H01G4/38
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1573852A
Cited
US2107423A
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US2053334A
Cited
CH208836A
Cited
US2346162A
Cited
US2527608A
Cited
US2526321A
Cited
US2552306A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-10-17 | 1959-04-18 | 1959-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-10-17 | 1963-04-18 | 1963-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-10-17 | 1967-04-18 | 1967-10-18 | $7700.00 | Window Closed / Lapsed |