Patent US1749553A successfully refreshed from Google Patents.
US2850264A
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Dual passage concentric pipe drill string coupling
Assignee: Individual
•
Filing: 1953-09-18
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Granted: 1958-09-02
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Expires: 1973-09-18
Abstract
No abstract record available.
Inventors
- 👤 Donovan B Grable
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:31
CPC Classifications
E; E21; E21B; E21B17/00; E21B17/10; E21B17/18; E21B21/00; E21B21/12
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1218359A
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US1781049A
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US1909075A
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US2054859A
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US2447340A
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US2494803A
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US2610028A
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US2676037A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-09-01 | 1962-03-03 | 1962-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-09-01 | 1966-03-03 | 1966-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-09-01 | 1970-03-03 | 1970-09-02 | $7700.00 | Window Closed / Lapsed |