US3528516A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Expansible underreamer for drilling large diameter earth bores
Assignee: Baker Hughes Holdings LLC
•
Filing: 1968-08-21
•
Granted: 1970-09-15
•
Expires: 1988-08-21
Abstract
No abstract record available.
Inventors
- 👤 Cicero C Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:37
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/26; E21B10/32; E21B10/34; E21B10/345
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1323905A
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US2277989A
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US2238998A
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US2354399A
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US2457628A
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US2799475A
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US2847189A
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US2814463A
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US2809016A
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US3196961A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-09-14 | 1974-03-16 | 1974-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-09-14 | 1978-03-16 | 1978-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-09-14 | 1982-03-16 | 1982-09-15 | $7700.00 | Window Closed / Lapsed |