US1286394A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for electric heating by high-frequency currents.
Assignee: Ajax Metal Co
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Filing: 1917-09-19
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Granted: 1918-12-03
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Expires: 1937-09-19
Abstract
No abstract record available.
Inventors
- 👤 Edwin F Northrup
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:27
CPC Classifications
H; H05; H05B; H05B6/00; H05B6/02; H05B6/34
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1921-12-02 | 1922-06-03 | 1922-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1925-12-02 | 1926-06-03 | 1926-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1929-12-02 | 1930-06-03 | 1930-12-03 | $7700.00 | Window Closed / Lapsed |