US3400938A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drilling head assembly
Assignee: Individual
•
Filing: 1966-09-16
•
Granted: 1968-09-10
•
Expires: 1986-09-16
Abstract
No abstract record available.
Inventors
- 👤 Williams Bob
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:25
CPC Classifications
E; E21; E21B; E21B33/00; E21B33/02; E21B33/08; E21B33/085; E21B21/00; E21B21/16
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
References Cited (Backward Citations)
US2176355A
Cited
US2170916A
Cited
US2768007A
Cited
US2846247A
Cited
US3052300A
Cited
US3023012A
Cited
US3128614A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-09-10 | 1972-03-11 | 1972-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-09-10 | 1976-03-11 | 1976-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-09-10 | 1980-03-11 | 1980-09-10 | $7700.00 | Window Closed / Lapsed |