US2223866A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic speed changer
Assignee: O S WALKER CO Inc
•
Filing: 1938-08-01
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Granted: 1940-12-03
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Expires: 1958-08-01
Abstract
No abstract record available.
Inventors
- 👤 John T Beechlyn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:10
CPC Classifications
H; H02; H02K; H02K7/00; H02K7/10; H02K7/11; H02K49/00; H02K49/12
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) | 1943-12-03 | 1944-06-03 | 1944-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1947-12-03 | 1948-06-03 | 1948-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1951-12-03 | 1952-06-03 | 1952-12-03 | $7700.00 | Window Closed / Lapsed |