Patent US2921781A successfully refreshed from Google Patents.
US2921781A
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US
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Selectively variable pressure apparatus for yieldably maintaining relatively movablemembers in spaced apart relation
Assignee: Air Lift Co
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Filing: 1956-10-31
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Granted: 1960-01-19
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Expires: 1976-10-31
Abstract
No abstract record available.
Inventors
- 👤 Don M Pemberton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:21
CPC Classifications
B; B60; B60G; B60G11/00; B60G11/32; B60G11/34; F; F16; F16F; F16F13/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-01-18 | 1963-07-20 | 1964-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-01-18 | 1967-07-20 | 1968-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-01-18 | 1971-07-20 | 1972-01-19 | $7700.00 | Window Closed / Lapsed |