Patent US2953722A successfully refreshed from Google Patents.
US2953722A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical protective relay systems
Assignee: English Electric Co Ltd
•
Filing: 1958-01-13
•
Granted: 1960-09-20
•
Expires: 1978-01-13
Abstract
No abstract record available.
Inventors
- 👤 Willis John
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:41
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/38; H02H3/382
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2299561A
Cited
US2804578A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-09-20 | 1964-03-21 | 1964-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-09-20 | 1968-03-21 | 1968-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-09-20 | 1972-03-21 | 1972-09-20 | $7700.00 | Window Closed / Lapsed |