Patent US2669431A successfully refreshed from Google Patents.
US2669431A
Expired / Lapsed
US
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Earth drilling apparatus
Assignee: CROWELL CONSULTING Co
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Filing: 1948-04-24
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Granted: 1954-02-16
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Expires: 1968-04-24
Abstract
No abstract record available.
Inventors
- 👤 John H Crowell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:26
CPC Classifications
E; E21; E21B; E21B7/00; E21B7/12; E21B7/124
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1435140A
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GB160865A
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US2001529A
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US2058287A
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US2187871A
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US2171672A
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US2283200A
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US2384851A
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US2512783A
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US2503516A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1957-02-15 | 1957-08-17 | 1958-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-02-15 | 1961-08-17 | 1962-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-02-15 | 1965-08-17 | 1966-02-16 | $7700.00 | Window Closed / Lapsed |