US2656151A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removable drop-in type back-pressure valve for drill strings
Assignee: Individual
•
Filing: 1949-08-10
•
Granted: 1953-10-20
•
Expires: 1969-08-10
Abstract
No abstract record available.
Inventors
- 👤 Herbert T Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:08
CPC Classifications
E; E21; E21B; E21B21/00; E21B21/10; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7837; Y10T137/7854
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1919510A
Cited
US2020599A
Cited
US2153812A
Cited
US2228241A
Cited
US2263639A
Cited
US2297031A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-10-19 | 1957-04-20 | 1957-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-10-19 | 1961-04-20 | 1961-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-10-19 | 1965-04-20 | 1965-10-20 | $7700.00 | Window Closed / Lapsed |