US3763453A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compressible air gap means compensating for thermal expansion of a lighting magnet coil
Assignee: Schneider Electric USA Inc
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Filing: 1972-02-22
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Granted: 1973-10-02
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Expires: 1992-02-22
Abstract
Abstract Lengths of sealed plastic tubing are positioned circumferentially of a lifting magnet coil prior to its encapsulation in a magnet case. The tubing provides an air space at the outer periphery of the magnet coil to prevent damage to the magnet by permitting thermal expansion of the coil without substantial force being applied through the encapsulating material.
Inventors
- 👤 C Schurr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:27
CPC Classifications
H; H01; H01F; H01F7/00; H01F7/06; H01F7/20; H01F7/206
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
78 words
In a lifting magnet comprising a magnet case having a sealed cavity, a magnet coil within the cavity, and encapsulating material in the cavity surrounding the magnet coil, the improvement comprising means generally peripherally disposed with respect to the magnet coil for forming a compressible air gap of controlled size and location in the encapsulating material to accommodate expansion of the magnet coil and permitting at least a portion of the encapsulating material to contact the magnet coil.
Claim 2
Dependent Claim
78 words
In a lifting magnet comprising a magnet case having a sealed cavity, a magnet coil within the cavity, and encapsulating material in the cavity surrounding the magnet coil, the improvement comprising means generally peripherally disposed with respect to the magnet coil for forming a compressible air gap of controlled size and location in the encapsulating material to accommodate expansion of the magnet coil and permitting at least a portion of the encapsulating material to contact the magnet coil.
Claim 3
Dependent Claim
67 words
In a lifting magnet comprising a magnet case having a sealed cavity, a magnet coil within the cavity, and encapsulating material in the cavity surrounding the magnet coil and filling portions of the cavity not occupied by the coil, the improvement comprising a compressible tube in the encapsulating material generally peripherally disposed with respect to the magnet coil and providing a compressible air space within the cavity.
Claim 4
Dependent Claim
67 words
In a lifting magnet comprising a magnet case having a sealed cavity, a magnet coil within the cavity, and encapsulating material in the cavity surrounding the magnet coil and filling portions of the cavity not occupied by the coil, the improvement comprising a compressible tube in the encapsulating material generally peripherally disposed with respect to the magnet coil and providing a compressible air space within the cavity.
Claim 5
Dependent Claim
25 words
A lifting magnet as in claim 2 wherein said magnet coil has an outer surface and including means attaching the tube to the outer surface.
Claim 6
Dependent Claim
13 words
A lifting magnet as in claim 2 wherein the tube has closed ends.
Claim 7
Dependent Claim
26 words
A lifting magnet as in claim 2 wherein the magnet coil has a predetermined width and the tube has a diameter less than said predetermined width.
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) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |