US3386521A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combination well drilling tool
Assignee: Drilex Systems Inc
•
Filing: 1965-11-26
•
Granted: 1968-06-04
•
Expires: 1985-11-26
Abstract
No abstract record available.
Inventors
- 👤 Chadderdon Jack
- 👤 Kirk R Shirley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:01
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/26; E21B10/32; E21B10/34; E21B10/345; E21B10/08; E21B10/18
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2170452A
Cited
US2679383A
Cited
US2784942A
Cited
US3171503A
Cited
US3208540A
Cited
US3196961A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-06-04 | 1971-12-04 | 1972-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-06-04 | 1975-12-04 | 1976-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-06-04 | 1979-12-04 | 1980-06-04 | $7700.00 | Window Closed / Lapsed |