US2138989A
Expired / Lapsed
US
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Automatic change-over device
Assignee: Phillips Petroleum Co
•
Filing: 1937-09-14
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Granted: 1938-12-06
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Expires: 1957-09-14
Abstract
No abstract record available.
Inventors
- 👤 Rosswell W Thomas
- 👤 Macsporran Charles
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:10
CPC Classifications
F; F17; F17C; F17C13/00; F17C13/04; F17C13/045; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7837; Y10T137/7838; Y10T137/8158; Y10T137/8225; Y10T137/8275; Y10T137/8292; Y10T137/8309; Y10T137/8593; Y10T137/87571; Y10T137/87676; Y10T137/87684
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) | 1941-12-05 | 1942-06-06 | 1942-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1945-12-05 | 1946-06-06 | 1946-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1949-12-05 | 1950-06-06 | 1950-12-06 | $7700.00 | Window Closed / Lapsed |