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US2548474A
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Differential grid blocking system for electronic frequency changers
Assignee: Allis Chalmers Corp
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Filing: 1950-05-31
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Granted: 1951-04-10
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Expires: 1970-05-31
Abstract
No abstract record available.
Inventors
- 👤 Alfred J Hansen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:25
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/10; H02H7/12; H02H7/125; H02H7/127
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2399322A
Cited
US2490290A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-04-09 | 1954-10-09 | 1955-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-04-09 | 1958-10-09 | 1959-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-04-09 | 1962-10-09 | 1963-04-10 | $7700.00 | Window Closed / Lapsed |