Patent US2725439A successfully refreshed from Google Patents.
US2725439A
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US
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Magnetic coupling device
Assignee: Ronald Trist and Co Ltd
•
Filing: 1951-06-29
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Granted: 1955-11-29
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Expires: 1971-06-29
Abstract
No abstract record available.
Inventors
- 👤 Newboult Henry Grattan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:01
CPC Classifications
H; H01; H01H; H01H36/00; H01H36/02; F; F22; F22D; F22D5/00; F22D5/08; G; G01; G01F; G01F23/00; G01F23/30; G01F23/32; G01F23/38
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US246718A
Cited
US2012153A
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GB476114A
Cited
US2204161A
Cited
GB553168A
Cited
US2371511A
Cited
US2520935A
Cited
US2475684A
Cited
US2522815A
Cited
US2577165A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-11-28 | 1959-05-30 | 1959-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-11-28 | 1963-05-30 | 1963-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-11-28 | 1967-05-30 | 1967-11-29 | $7700.00 | Window Closed / Lapsed |