US2235631A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable stroke pump
Assignee: Shell Development Co
•
Filing: 1939-09-13
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Granted: 1941-03-18
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Expires: 1959-09-13
Abstract
No abstract record available.
Inventors
- 👤 Frenkel Gustav Adolf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:17
CPC Classifications
F; F04; F04B; F04B1/00; F04B1/04; F04B1/06; F04B1/07; Y; Y10; Y10T; Y10T74/00; Y10T74/16; Y10T74/1625; Y10T74/165; Y10T74/18; Y10T74/18056; Y10T74/18176; Y10T74/18182
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) | 1944-03-17 | 1944-09-16 | 1945-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-03-17 | 1948-09-16 | 1949-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-03-17 | 1952-09-16 | 1953-03-18 | $7700.00 | Window Closed / Lapsed |