Patent ID: 6274073
Filing Date: 2001-08-14
Classification: B29C,B29D,F16L

Abstract:
A process for producing in an injection mold a pipe fitting having at least some areas consisting of thermally weldable welding material, the pipe fitting configured to be attached to or to connect or repair conduits consisting of thermally weldable material, the method comprising the steps of:providing channels formed as windings and provided with channel walls in a first injection mold;giving a wavy shape to at least some sections of a heating wire so as to form a wavy heating strand;laying the wavy heating strand into the first injection mold between the channel walls of the channels;introducing a first welding material into the channels so that a first broad side of the wavy shape of the heating strand is pressed against a first mold surface of the injection mold, and producing an intermediate product having the wavy heating strand embedded in the intermediate product and having an outside surface which, in the pipe fitting, will form the contact surface with a conduit, wherein the outside surface is formed by the first mold surface against which the heating strand is pressed and wherein the first broad side of the wavy shape of the heating strand remains visible at the outer surface of the intermediate product;placing the intermediate product into a second injection mold configured to produce the pipe fitting and positioning the outer surface on a second mold surface of the second injection mold;introducing a second welding material into the second injection mold for molding the pipe fitting and forming on the second mold surface the contact surface of the pipe fitting for contacting the conduits, wherein the first broad side of the wavy shape of the heating strand remains visible at the contact surface of the end product after solidification of the second welding material.