Patent US2252881A successfully refreshed from Google Patents.
US2252881A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Blank holder circuit with automatic release of blank holder pressure on idle stroke
Assignee: Hydraulic Development Corp Inc
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Filing: 1939-03-27
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Granted: 1941-08-19
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Expires: 1959-03-27
Abstract
No abstract record available.
Inventors
- 👤 Ernst Walter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:03
CPC Classifications
B; B21; B21D; B21D24/00; B21D24/10; B21D24/12; B21D24/14
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) | 1944-08-18 | 1945-02-17 | 1945-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-08-18 | 1949-02-17 | 1949-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-08-18 | 1953-02-17 | 1953-08-19 | $7700.00 | Window Closed / Lapsed |