Patent US2568256A successfully refreshed from Google Patents.
US2568256A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Safety drilling and fishing bumper sub
Assignee: Individual
•
Filing: 1947-01-24
•
Granted: 1951-09-18
•
Expires: 1967-01-24
Abstract
No abstract record available.
Inventors
- 👤 Donald U Shaffer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:19
CPC Classifications
E; E21; E21B; E21B17/00; E21B17/02; E21B17/04; E21B17/07; E21B31/00; E21B31/107
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1954-09-17 | 1955-03-19 | 1955-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-09-17 | 1959-03-19 | 1959-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-09-17 | 1963-03-19 | 1963-09-18 | $7700.00 | Window Closed / Lapsed |