Patent US2499543A successfully refreshed from Google Patents.
US2499543A
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Core lifting arrangement for deep well drills
Assignee: Individual
•
Filing: 1946-09-17
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Granted: 1950-03-07
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Expires: 1966-09-17
Abstract
No abstract record available.
Inventors
- 👤 Lawrence E Townsend
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:14
CPC Classifications
E; E21; E21B; E21B25/00; E21B25/10; E21B25/12
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) | 1953-03-06 | 1953-09-05 | 1954-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-03-06 | 1957-09-05 | 1958-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-03-06 | 1961-09-05 | 1962-03-07 | $7700.00 | Window Closed / Lapsed |