Patent US2759124A successfully refreshed from Google Patents.
US3487294A
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US
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Differential phase shift induction well logging system
Assignee: Dresser Industries Inc
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Filing: 1968-01-22
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Granted: 1969-12-30
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Expires: 1988-01-22
Abstract
No abstract record available.
Inventors
- 👤 Arthur H Youmans
- 👤 Eric C Hopkkinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:01
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/18; G01V3/26; G01V3/28
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3020470A
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US2623923A
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US2903642A
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US2929984A
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US3051892A
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US3147429A
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US3278839A
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US3259836A
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US3259838A
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US3398356A
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US3337796A
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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) | 1972-12-29 | 1973-06-30 | 1973-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-12-29 | 1977-06-30 | 1977-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-12-29 | 1981-06-30 | 1981-12-30 | $7700.00 | Window Closed / Lapsed |