Patent US291587A successfully refreshed from Google Patents.
US1991874A
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Centrifugal apparatus
Assignee: AMERICAN TOOL AND MARCHINE Co
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Filing: 1930-08-19
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Granted: 1935-02-19
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Expires: 1950-08-19
Abstract
No abstract record available.
Inventors
- 👤 Frank I Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:36
CPC Classifications
B; B04; B04B; B04B7/00; B04B7/02; B04B7/06
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) | 1938-02-18 | 1938-08-20 | 1939-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1942-02-18 | 1942-08-20 | 1943-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1946-02-18 | 1946-08-20 | 1947-02-19 | $7700.00 | Window Closed / Lapsed |