US3372761A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Maximum allowable back pressure controller for a drilled hole
Assignee: Individual
•
Filing: 1965-06-30
•
Granted: 1968-03-12
•
Expires: 1985-06-30
Abstract
No abstract record available.
Inventors
- 👤 Adrianus Wilhelmus Van Gils
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:24
CPC Classifications
E; E21; E21B; E21B21/00; E21B21/08; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7758; Y10T137/7762; Y10T137/7769
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US2285049A
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US2741262A
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US2955614A
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US3198207A
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US3213939A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-03-12 | 1971-09-11 | 1972-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-03-12 | 1975-09-11 | 1976-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-03-12 | 1979-09-11 | 1980-03-12 | $7700.00 | Window Closed / Lapsed |