| 摘要 |
Sheets of thermoplastic material are welded together by passing a hot wedge 5 between overlapping edges 3, 4 of the sheets so as to melt the surfaces 1, 2 of the sheets in contact with the wedge, adding a small amount of molten thermoplastic material between the overlapping edges and thereafter pressing the edges together, e.g. by a roller 7, so that when they have cooled any voids and creases are filled with the additional thermoplastic material. The wedge 5 may be heated by an induction coil 6, Fig. 1, or by the passage of a high amperage low voltage electric current therethrough, Fig. 2 (not shown). The temperature of the wedge is controlled by a controller connected to a temperature sensing device 8 located at the pointed end of the wedge. The additional thermoplastic material may be supplied through a nozzle (18), Fig. 3 (not shown), near the pointed end of the wedge. Alternatively, this material is introduced at the side of the wedge and the roller, Fig. 4 (not shown). <IMAGE> |
