| 摘要 |
In the manufacture of an electrofusion coupler, a winding (2) of an electrical resistance heating wire is wound directly around a mandrel (10) which comprises two parts providing respective ends of the mandrel. The mandrel supports electrically conducting terminal elements (5,6) by means of supporting locations (11) on the mandrel parts which form an integral part of the mandrel. The resistance wire (2) wound around the mandrel is connected to the electrically conducting terminal elements (5,6). Subsequently a body of thermoplastics (1) is moulded around the mandrel to form the electrofusion coupler, and thereafter the mandrel parts are extracted axially from the electrofusion coupler from opposite ends, leaving the winding (2) and terminal elements (5,6) in place in the electrofusion coupler. In a variant, a thermoplastic preform (3) is manufactured having electrically conducting terminal plates (5) secured thereto, the preform having an electrical resistance heating wire (2) wound therearound and secured to said terminal plates. An outer thermoplastics jacket (1) is then moulded around the wound preform (3) and said terminal plates (5), with bores being formed in said outer jacket extending to holes in the terminal plates. Subsequently electrical terminals having screw-threaded shanks (9) are screwed into said bores and into electrical contact with said terminal plates (5). <IMAGE> |
