US3481412A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coring apparatus with hydraulically retrievable inner core barrel
Assignee: Norton Christensen Inc
•
Filing: 1967-08-24
•
Granted: 1969-12-02
•
Expires: 1987-08-24
Abstract
No abstract record available.
Inventors
- 👤 David S Rowley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 23:19
CPC Classifications
E; E21; E21B; E21B25/00; E21B25/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2277989A
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US2023724A
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US2145170A
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US2294521A
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US2740480A
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US3120282A
Cited
US3312282A
Cited
US3332493A
Cited
US3367421A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-12-01 | 1973-06-02 | 1973-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-12-01 | 1977-06-02 | 1977-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-12-01 | 1981-06-02 | 1981-12-02 | $7700.00 | Window Closed / Lapsed |