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Patent US3340939A successfully refreshed from Google Patents.
US3340939A
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Core lifter apparatus
Assignee: SPENCER WRIGHT INDUSTRIES Inc A CORP OF TENNESSEE
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Filing: 1965-08-27
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Granted: 1967-09-12
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Expires: 1985-08-27
Abstract
No abstract record available.
Inventors
- 👤 Leonard A Lindelof
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 05:20
CPC Classifications
E; E21; E21B; E21B25/00; E21B25/02; E21B25/10; E21B25/12
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
129 words
IN CORE BARREL APPARATUS HAVING A DRILL STEM WITH A CORE BIT AT ITS INNER END AND A CORE BARREL INNER TUBE ASSEMBLY ADAPTED TO BE MOVED THROUGH THE DRILL STEM TO A LATCHED POSITION ADJACENT THE BIT, SAID CORE BARREL INNER TUBE ASSEMBLY INCLUDING A CORE RECEIVING TUBE AND A CORE LIFTER HAVING AN OUTER TAPERED SURFACE, THE IMPROVEMENT COMPRISING A STOP RING AND A CORE LIFTER CASE CONNECTED TO THE ONE END OF THE CORE RECEIVING TUBE TO EXTEND AXIALLY AWAY FROM SAID CORE RECEIVING TUBE AND TO MOUNT SAID CORE LIFTER FOR LIMITED AXIAL MOVEMENT THEREIN, SAID CORE LIFTER CASE HAVING MEANS FOR RECEIVINGLY SEATING SAID STOP RING ADJACENT THE CONNECTION OF SAID CASE TO THE CORE RECEIVING TUBE AND A TRANVERSE INNER TAPERED SURFACE OF
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) | 1970-09-11 | 1971-03-13 | 1971-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-09-11 | 1975-03-13 | 1975-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-09-11 | 1979-03-13 | 1979-09-12 | $7700.00 | Window Closed / Lapsed |