Patent US2421056A successfully refreshed from Google Patents.
US2421056A
Expired / Lapsed
US
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Conveyor control system
Assignee: Parkersburg Rig and Reel Co
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Filing: 1943-12-27
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Granted: 1947-05-27
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Expires: 1963-12-27
Abstract
No abstract record available.
Inventors
- 👤 George E Dake
- 👤 Edgar F Speiden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:18
CPC Classifications
B; B65; B65G; B65G23/00; B65G2812/00; B65G2812/02; B65G2812/02009; B65G2812/02089
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-05-26 | 1950-11-25 | 1951-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-05-26 | 1954-11-25 | 1955-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-05-26 | 1958-11-25 | 1959-05-27 | $7700.00 | Window Closed / Lapsed |