Abstract A method of joining together by heat welding two tubular elements of a meltable thermoplastic material. The elements are arranged so that one tubular element receives one end of the other element in a telescoping manner to form an annular space between the two elements. A welding sleeve of a meltable thermoplastic material is positioned in the annular space between the two tubular elements. Heating elements are also arranged in the annular space for heating and welding the welding sleeve to the surfaces of the two tubular elements. Additionally, a ring-shaped body which becomes enlarged when heat is applied thereto is positioned in the annular space between the two tubular elements and the heating elements are arranged on the outer surface of the ring-shaped body. The two tubular elements and the welding sleeve are pressed together by the force exerted by the ring-shaped body whose material shape is changed from a state in which it is originally dimensionally stable in heat to a state in which it is dimensionally unstable in heat.
A system of joining together by heat-welding two tubular elements of thermoplastic material and of mutually different diameters, subsequent to inserting one end of one said element into one end of the other to leave an annular gap therebetween, said system comprising: (a) a ring-shaped welding sleeve which is located in said gap and which is made of a meltable thermoplastic material, (b) a recoverably deformed pressure-generating ring-shaped body made of a heat-recoverable plastic material inserted within the welding sleeve, (c) heat-generating means arranged to cooperate with said ring-shaped body in a manner such as to heat the same and to bring the welding sleeve and said mutually opposing wall surfaces to a fusible state.
Claim 2
Independent Claim
115 words
A system of joining together by heat-welding two tubular elements of thermoplastic material and of mutually different diameters, subsequent to inserting one end of one said element into one end of the other to leave an annular gap therebetween, said system comprising: (a) a ring-shaped welding sleeve which is located in said gap and which is made of a meltable thermoplastic material, (b) a recoverably deformed pressure-generating ring-shaped body made of a heat-recoverable plastic material inserted within the welding sleeve, (c) heat-generating means arranged to cooperate with said ring-shaped body in a manner such as to heat the same and to bring the welding sleeve and said mutually opposing wall surfaces to a fusible state.
Claim 3
Dependent Claim
37 words
A system according to claim 1, in which the heat-recoverable body is a hollow annular element having heating filaments wound around the wall thereof and being pre-deformed to exhibit a part-flattened configuration in cross-section through said wall.