US2438197A
Expired / Lapsed
US
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Phase-selective variable-frequency oscillatory system
Assignee: Hazeltine Research Inc
•
Filing: 1942-12-31
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Granted: 1948-03-23
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Expires: 1962-12-31
Abstract
No abstract record available.
Inventors
- 👤 Harold A Wheeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:13
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/08; G01V3/10; G01V3/104; G01V3/105; G01V3/107
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1951-03-23 | 1951-09-22 | 1952-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-03-23 | 1955-09-22 | 1956-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-03-23 | 1959-09-22 | 1960-03-23 | $7700.00 | Window Closed / Lapsed |