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Patent US1920150A successfully refreshed from Google Patents.
US1920150A
Expired / Lapsed
US
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Direct-current voltage transformation apparatus
Assignee: CROSLEY RADIO Corp
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Filing: 1932-12-07
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Granted: 1933-07-25
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Expires: 1952-12-07
Abstract
No abstract record available.
Inventors
- 👤 Ronald J Rockwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:42
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/34; H02M3/38; H02M3/42
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) | 1936-07-24 | 1937-01-23 | 1937-07-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1940-07-24 | 1941-01-23 | 1941-07-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1944-07-24 | 1945-01-23 | 1945-07-25 | $7700.00 | Window Closed / Lapsed |