Patent US3215861A successfully refreshed from Google Patents.
US2949281A
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US
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Large diameter earth boring drill
Assignee: Hughes Tool Co
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Filing: 1957-09-06
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Granted: 1960-08-16
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Expires: 1977-09-06
Abstract
No abstract record available.
Inventors
- 👤 George W Baur
- 👤 Erwin A Morlan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:07
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/08; E21B10/18; E21B10/26; E21B10/28
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) | 1963-08-16 | 1964-02-15 | 1964-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-08-16 | 1968-02-15 | 1968-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-08-16 | 1972-02-15 | 1972-08-16 | $7700.00 | Window Closed / Lapsed |