Von Roll Ag

Other

Werner Sturm

Apparatus for producing an arc welded sleeve

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.

Thermoplastic welding sleeve

Method and device for connecting pipe components made of weldable plastic

Welding muff of thermoplastic material

Method and apparatus for joining thermoplastic line elements

A sleeve member (4) formed from a pipe length by expansion is placed over a mandrel onto which are wound the spaced turns (7) of a resistance heating wire (6). By heating sleeve member (4) the latter is shrunk onto the turns (7). By electrically producing heat in wire (6) material flows around the expanding turns (7) and embed the latter completely in sleeve member (4), projecting material portions (8, 9) being formed in the vicinity of turns (7). Thus, a protection against electric shock hazard is obtained for turns (7) and after-working is made unnecessary for the standing back edge portions of inner wall (5) which deform inwards during manufacture.

Welding sleeve of thermoplastic material

The disclosed sleeve is of the type including a resistance heating wire embedded in a thermoplastic sleeve material. A first sleeve member of insulating thermoplastic is molded with axially spaced integral annular receptacle wall members extending out from the outer surface and defining recesses. The walls have two diametrically opposite guide slots. Extending upwards from the center of each recess is a wire support stud. A resistance wire wound on the first sleeve between the wall members has its end sections passed through the slots and over the support stud, so that portions of the wire lie exposed against the side faces of the stud. A second sleeve member of insulating material is molded over the first sleeve so that the wire is embedded in the second sleeve but remains exposed within the recesses. The second sleeve material fills in the slots above the wire to thereby fix the wire in place in the slots. This permits a mating connector element to be inserted in the recess with its bore receiving the wire and wire support, so that electrical contact is made to the wire.

Electrically welding plastic sleeve

A thermoplastic synthetic resin sleeve to be slipped over the end of a tubular member to be joined to another such member has a winding of resistance heating wire adjacent the inner surface of the sleeve. Connectors at the ends of the wire are provided to connect the wire to a source of electrified power. Small diameter wire is chosen, the resistance thereof being selected as an inverse function of sleeve diameter, so that an unregulated source of power can be used. A visual indication is provided to indicate when a good weld joint has been made.

Electric welding muff

To permit efficient heat welding of pipe fittings, and the like, of thermpolastic material to thermoplastic pipes, by electrically heating of the fitting, the fitting is made in two concentric portions, the inner portion having a heating wire applied to the outside thereof, the heating wire and inner portion being covered by the outer portion, for example injected thereover.

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Hagendorf, Switzerland

Werner Sturm