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US 4,375,591 AGranted
Thermoplastic welding sleeve
OwnerWerner Sturminventor
Life of this patent
Estimating the term…
Abstract
A welding sleeve has an inner body with a grooved outer surface, a surrounding outer body and a resistance heating wire therebetween. The inner wall, between the bottoms of the grooves and inner surface of the inner body, increases in thickness toward the axial center of the sleeve. During welding, the center of the sleeve and the adjacent axial ends of the parts to be joined are heated later than the axial ends of the sleeve, thereby increasing the stability of the joint formed. Also, disclosed are improved mold assemblies for forming the welding sleeve.
Claims8
A welding sleeve for joining thermoplastic line members, comprising:
- an inner body of thermoplastic material extending along an axis, having an outer surface with grooves separated by webs and having an inner surface, said inner body having a wall thickness between bottoms of said grooves and said inner surface which increases toward an axial center of said inner body;
- a resistence heating wire received in said groove at said bottoms thereof;
- and
- an outer body of thermoplastic material surrounding said inner body and said wire and extending into said grooves.
1 more element
Dependencies are inferred from the claim text.