Patent US2539970A successfully refreshed from Google Patents.
US2539970A
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Safety control for hydraulic brake systems
Assignee: JOHN C URQUHART
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Filing: 1948-03-11
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Granted: 1951-01-30
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Expires: 1968-03-11
Abstract
No abstract record available.
Inventors
- 👤 Pollard Harold
- 👤 Crichton W Haggart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:36
CPC Classifications
B; B60; B60T; B60T11/00; B60T11/10; B60T11/28; B60T11/32
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) | 1954-01-29 | 1954-07-31 | 1955-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-01-29 | 1958-07-31 | 1959-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-01-29 | 1962-07-31 | 1963-01-30 | $7700.00 | Window Closed / Lapsed |