Patent US4644942A successfully refreshed from Google Patents.
Patent US3398804A successfully refreshed from Google Patents.
US3398804A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of drilling a curved bore
Assignee: Sinclair Research Inc
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Filing: 1965-10-08
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Granted: 1968-08-27
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Expires: 1985-10-08
Abstract
No abstract record available.
Inventors
- 👤 Don R Holbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:04
CPC Classifications
E; E21; E21B; E21B7/00; E21B7/04; E21B7/06; E21B7/061
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) | 1971-08-27 | 1972-02-26 | 1972-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-08-27 | 1976-02-26 | 1976-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-08-27 | 1980-02-26 | 1980-08-27 | $7700.00 | Window Closed / Lapsed |