Segmented expansion absorber for lifting magnet
AssigneeSquare D Company
InventorArmand G. Mueller
Life of this patent
Estimating the term…
Abstract
A lifting magnet has lengths of sealed plastic tubing positioned circumferentially of its coil prior to its encapsulation in a magnet case. The tubing is hermetically sealed every few inches along its entire length in order to divide the tubing into individually sealed segments. The sealed segments form compressible air spaces at the outer periphery of the magnet coil which permit thermal expansion of the coil and the encapsulating material without substantial force being applied by the coil and the encapsulating material to the magnet case. In the event any one or a few segments of the tubing are perforated or otherwise disabled in the course of fabrication or assembly of the magnet, the balance of the sealed segments still serve their intended purpose.
Claims6
A lifting magnet, comprising:
- a magnet case having a sealed cavity;
- a magnet coil mounted within the cavity;
- potting compound encapsulating the magnet coil and substantially filling any remaining voids in the cavity;
- and means for absorbing the compressive forces acting upon the encapsulating compound due to expansion of the magnet coil during its operation, said means comprising individual hermetically sealed compartments serially connected to each other and each containing a predetermined volume of compressible fluid generally arranged and disposed to substantially surround the coil in order to provide a predetermined number of compartments, if none are punctured, providing a volume of compressible fluid in excess of said predetermined volume, whereby some segments can be disabled in the course of fabrication, assembly and encapsulation of the magnet and coil without rendering the entire absorbing means inoperative.
Dependencies are inferred from the claim text.