US2721994A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Self-balancing electro-magnetic proximity detector
Assignee: Westinghouse Air Brake Co
•
Filing: 1952-11-14
•
Granted: 1955-10-25
•
Expires: 1972-11-14
Abstract
No abstract record available.
Inventors
- 👤 Robert H Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:24
CPC Classifications
B; B61; B61L; B61L1/00; B61L1/16; B61L1/161; B61L1/163; B61L1/165; B61L1/167; G; G01; G01S; G01S11/00; G01S11/02; G01S11/06
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1658953A
Cited
US2112826A
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US2488815A
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US2454687A
Cited
US2580155A
Cited
US2640978A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-10-24 | 1959-04-25 | 1959-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-10-24 | 1963-04-25 | 1963-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-10-24 | 1967-04-25 | 1967-10-25 | $7700.00 | Window Closed / Lapsed |