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US2917281A
Expired / Lapsed
US
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Releasing head for submarine conductor casing
Assignee: Richfield Oil Corp
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Filing: 1957-07-26
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Granted: 1959-12-15
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Expires: 1977-07-26
Abstract
No abstract record available.
Inventors
- 👤 David C Kofahl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:35
CPC Classifications
E; E21; E21B; E21B7/00; E21B7/12; E21B29/00; E21B29/12
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) | 1962-12-14 | 1963-06-15 | 1963-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-12-14 | 1967-06-15 | 1967-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-12-14 | 1971-06-15 | 1971-12-15 | $7700.00 | Window Closed / Lapsed |