US3439757A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drilling apparatus
Assignee: Individual
•
Filing: 1968-03-12
•
Granted: 1969-04-22
•
Expires: 1988-03-12
Abstract
No abstract record available.
Inventors
- 👤 Wayland D Elenburg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 06:10
CPC Classifications
E; E21; E21B; E21B17/00; E21B17/10; E21B17/1092; E21B10/00; E21B10/08; E21B10/18; E21B21/00; E21B21/12
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-04-21 | 1972-10-21 | 1973-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-04-21 | 1976-10-21 | 1977-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-04-21 | 1980-10-21 | 1981-04-22 | $7700.00 | Window Closed / Lapsed |