Patent US2497522A successfully refreshed from Google Patents.
US2497522A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for operating devices having a negative resistance characteristic from an alternating electric current supply circuit
Assignee: Hitachi Rail STS USA Inc
•
Filing: 1947-05-09
•
Granted: 1950-02-14
•
Expires: 1967-05-09
Abstract
No abstract record available.
Inventors
- 👤 Walker Alec Hervey Bennett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:27
CPC Classifications
H; H05; H05B; H05B41/00; H05B41/14; H05B41/36; H05B41/38; H05B41/39; H05B41/391; G; G05; G05F; G05F1/00; G05F1/10; G05F1/12; G05F1/32; G05F1/325
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1953-02-13 | 1953-08-15 | 1954-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-02-13 | 1957-08-15 | 1958-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-02-13 | 1961-08-15 | 1962-02-14 | $7700.00 | Window Closed / Lapsed |