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Patent US2647585A successfully refreshed from Google Patents.
US2647585A
Expired / Lapsed
US
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Heater for oil and other wells
Assignee: VIOLA VIOLET ROBERTS
•
Filing: 1949-02-12
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Granted: 1953-08-04
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Expires: 1969-02-12
Abstract
No abstract record available.
Inventors
- 👤 George H Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:04
CPC Classifications
E; E21; E21B; E21B36/00
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) | 1956-08-03 | 1957-02-02 | 1957-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-08-03 | 1961-02-02 | 1961-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-08-03 | 1965-02-02 | 1965-08-04 | $7700.00 | Window Closed / Lapsed |