US2540700A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and device for hardening of articles by high-frequency currents
Assignee: Individual
•
Filing: 1947-02-25
•
Granted: 1951-02-06
•
Expires: 1967-02-25
Abstract
No abstract record available.
Inventors
- 👤 Stivin Jiri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:20
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/02; H05B6/36; H05B6/362; C; C21; C21D; C21D9/00; C21D9/30; Y; Y02; Y02P; Y02P10/00; Y02P10/25
Claims Analysis
Total Claims: 0
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-02-05 | 1954-08-07 | 1955-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-02-05 | 1958-08-07 | 1959-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-02-05 | 1962-08-07 | 1963-02-06 | $7700.00 | Window Closed / Lapsed |