Patent US1978991A successfully refreshed from Google Patents.
US1978991A
Expired / Lapsed
US
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Automatic double acting blow-out preventer for use in oil well drilling
Assignee: Individual
•
Filing: 1929-01-03
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Granted: 1934-10-30
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Expires: 1949-01-03
Abstract
No abstract record available.
Inventors
- 👤 Charles A Dailey
- 👤 John V Box
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:32
CPC Classifications
E; E21; E21B; E21B33/00; E21B33/02; E21B33/03; E21B33/06
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) | 1937-10-29 | 1938-04-30 | 1938-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1941-10-29 | 1942-04-30 | 1942-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1945-10-29 | 1946-04-30 | 1946-10-30 | $7700.00 | Window Closed / Lapsed |