Composite electrical insulator and method of manufacturing same
AssigneeNGK Insulators, Ltd.
InventorShigeo Ishino
Life of this patent
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Abstract
A composite electrical insulator includes a metal fitting (3, 4) fixedly secured to a fiber-reinforced plastic rod (1) at one end thereof. The rod has a stress-relieved zone (8) situated opposite to the metal fitting (3, 4), and formed by a heat treatment of the rod (1) after an end portion of the rod (1) has been inserted into a bore (5) in the metal fitting (3, 4) and the metal fitting (3, 4) fixedly secured to the rod (1). The heat treatment of the rod (1) is performed at a temperature which is not lower than a heat transition temperature of a matrix resin of the fiber-reinforced plastic material.
Claims9
A composite electrical insulator comprising:
- a rod comprised of a fiber-reinforced plastic material and having an end portion;
- and
- a metal fitting including a sleeve portion having a bore into which said end portion of the rod is inserted, said metal fitting being fixedly secured to said rod provided in said sleeve portion by caulking the sleeve portion;
- wherein a portion of the rod that extends along a caulked region of the sleeve portion is locally heated to form a stress-relieved zone in the rod.
A method of manufacturing a composite electrical insulator, comprising the steps of:
- providing a rod comprised of a fiber-reinforced plastic material and having one end portion, and a metal fitting including a sleeve portion having a bore;
- inserting said end portion of the rod into the bore in the sleeve portion of the metal fitting;
- fixedly securing said rod provided in the sleeve portion of the metal fitting by caulking the sleeve portion;
- and
- subsequently locally heating a portion of the rod that extends along a caulked region of the sleeve portion to form a stress-relieved zone in the rod.
Dependencies are inferred from the claim text.