Patent US2808231A successfully refreshed from Google Patents.
US2808231A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drill pipe section
Assignee: CLINTON O ENGSTRAND
•
Filing: 1956-01-26
•
Granted: 1957-10-01
•
Expires: 1976-01-26
Abstract
No abstract record available.
Inventors
- 👤 Willard B Kimbrell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:30
CPC Classifications
E; E21; E21B; E21B17/00; Y; Y10; Y10S; Y10S285/00; Y10S285/922
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) | 1960-09-30 | 1961-04-01 | 1961-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-09-30 | 1965-04-01 | 1965-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-09-30 | 1969-04-01 | 1969-10-01 | $7700.00 | Window Closed / Lapsed |