| 摘要 |
1,249,168. Seaming non-metallic sheet material. VEREINIGTE DEUTSCHE METALLWERKE A.G. 2 July, 1969 [6 July, 1968], No. 33486/69. Heading B5K. Edge portions 2 of two elements 9 of thermoplastic material, e.g. polyethylene container parts, each portion 2 being formed with a recess 4 between walls 5, 6 of which the wall 5 is longer and thicker than the wall 6, are welded together so that substantially no flash is formed on at least one side of the joint by heating the portions 2 until the material of the walls 5 is plasticized substantially throughout and forcing the walls 5 together until faces 10 of the walls 6 are in adhesive contact so that the material of the walls 5 flows into the recesses 4. In one embodiment, Figs. 1 and 4, the walls 5 are heated by being pressed into contact with a polished heating plate (11), Fig. 2 (not shown), and are pressed together after being removed from the plate (11). Plasticized parts of the walls 5 flow partly into a cavity 3 formed by the co-operating recesses 4 and partly out on that side of the joint where no recesses are provided to form a flash which can subsequently be removed by machining. In a modification, Fig. 7, the walls 5 are chamfered. Different forms of ends to be welded are described, Figs. 6, 8, 9 and 10 (all not shown). In a further modification (not shown), the walls to be heated do not supply all of the plasticized material for the joint and a filler rod is supplied and is heated together with the walls. |
