US2863638A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Rotary drill string apparatus
Assignee: Caterpillar Global Mining LLC
•
Filing: 1955-04-19
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Granted: 1958-12-09
•
Expires: 1975-04-19
Abstract
No abstract record available.
Inventors
- 👤 Herbert W Thornburg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:27
CPC Classifications
E; E21; E21B; E21B17/00; E21B17/02; E21B17/03; E21B3/00; E21B3/02; E21B3/022
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1728111A
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US1983545A
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US1857528A
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US1960688A
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US2439751A
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US2620165A
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US2765147A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-12-08 | 1962-06-09 | 1962-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-12-08 | 1966-06-09 | 1966-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-12-08 | 1970-06-09 | 1970-12-09 | $7700.00 | Window Closed / Lapsed |