US2661802A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combined shut-in and back circulation tool
Assignee: Johnston Testers Inc
•
Filing: 1950-03-09
•
Granted: 1953-12-08
•
Expires: 1970-03-09
Abstract
No abstract record available.
Inventors
- 👤 Mordica O Johnston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:45
CPC Classifications
E; E21; E21B; E21B33/00; E21B33/10; E21B33/12; E21B34/00; E21B34/06; E21B34/12; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/87265
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1625044A
Cited
US1984375A
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US2073107A
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US2197078A
Cited
US2327610A
Cited
US2229636A
Cited
US2337752A
Cited
US2404825A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1956-12-07 | 1957-06-08 | 1957-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-12-07 | 1961-06-08 | 1961-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-12-07 | 1965-06-08 | 1965-12-08 | $7700.00 | Window Closed / Lapsed |