Patent US3138932A successfully refreshed from Google Patents.
US3138932A
Expired / Lapsed
US
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Locating an offshore drilling platform
Assignee: Richfield Oil Corp
•
Filing: 1961-04-14
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Granted: 1964-06-30
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Expires: 1981-04-14
Abstract
No abstract record available.
Inventors
- 👤 David C Kofahl
- 👤 Jr Charles E Wakefield
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:58
CPC Classifications
E; E02; E02B; E02B17/00; E02B17/02; E02B17/021; E02B2017/0039; E02B2017/0043; E02B2017/0047; E02B2017/0056; E02B2017/0073; E02B2017/0082
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US2592626A
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US2775869A
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US2935854A
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US2931184A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1967-06-30 | 1967-12-30 | 1968-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-06-30 | 1971-12-30 | 1972-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-06-30 | 1975-12-30 | 1976-06-30 | $7700.00 | Window Closed / Lapsed |