Patent US2979141A successfully refreshed from Google Patents.
US2979141A
Expired / Lapsed
US
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Earth boring apparatus
Assignee: Individual
•
Filing: 1957-11-13
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Granted: 1961-04-11
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Expires: 1977-11-13
Abstract
No abstract record available.
Inventors
- 👤 Charles W Kandle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:39
CPC Classifications
E; E21; E21B; E21B7/00; E21B7/04; E21B7/046; E21B7/26
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) | 1964-04-10 | 1964-10-10 | 1965-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-04-10 | 1968-10-10 | 1969-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-04-10 | 1972-10-10 | 1973-04-11 | $7700.00 | Window Closed / Lapsed |