US2294521A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removable plug for drilling strings
Assignee: Shell Development Co
•
Filing: 1941-06-24
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Granted: 1942-09-01
•
Expires: 1961-06-24
Abstract
No abstract record available.
Inventors
- 👤 Steadman Horace Vivian
- 👤 Ellis E Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:33
CPC Classifications
E; E21; E21B; E21B37/00; E21B33/00; E21B33/02; E21B33/03; E21B33/06; E21B33/10; E21B33/12; E21B33/126; E21B33/1265
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1945-08-31 | 1946-03-02 | 1946-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1949-08-31 | 1950-03-02 | 1950-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1953-08-31 | 1954-03-02 | 1954-09-01 | $7700.00 | Window Closed / Lapsed |