US2840168A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Releasable coupling and safety sub
Assignee: Individual
•
Filing: 1953-12-10
•
Granted: 1958-06-24
•
Expires: 1973-12-10
Abstract
No abstract record available.
Inventors
- 👤 Dan E Berry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:53
CPC Classifications
E; E21; E21B; E21B17/00; E21B17/02; E21B17/04; E21B17/06
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) | 1961-06-23 | 1961-12-23 | 1962-06-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-06-23 | 1965-12-23 | 1966-06-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-06-23 | 1969-12-23 | 1970-06-24 | $7700.00 | Window Closed / Lapsed |