| 摘要 |
1,043,071. Seaming non-metallic sheet material. E. TILGER. Aug. 7, 1964 [Aug. 8, 1963], No. 32267/64. Heading B5K. Thermoplastics materials are welded by providing metal particles between the portions of plastic to be welded together and heating the metal particles by electric induction so that the plastic surrounding the metal particles is fluidized and welded. Metal particles 0.35 mm. in diameter are spaced 0.3 mm. apart on a sheet 350 microns thick. The particles are heated for 0.5 seconds and reach a surface temperature of about 400‹ C. In one embodiment, Figs. 1 and 3, a bag is formed from a piece of plastics tubing the end portions 2, 3 of which are folded over and joined by welded seams 4, metal particles 5 being embedded in the seam regions in the sheets 6, 7 to be joined prior to welding. In a second embodiment, Figs. 5 and 6, portions 12, 13 are folded over about lines 10, 11 and triangles 14, 15 of end pockets 16 are provided with a strip 17 of metal particles. The portion 12 is also provided with a metal particle strip 18 on the underside thereof. The portion 12 is first folded about the line 10 and the portion 13 about the line 11 and the particles heated by induction. At the bottom 20 one pocket 19 is provided with a continuous strip 21 of metal particles. A sheet 22, Fig. 6, of tubing is placed in the centre of the strip 21 to form a valve. A portion 23 is folded about a line 24 and then a portion 25 about a line 26 so that a metal particle strip 27 on the portion 23 overlies the portion 25. Metal particle strips 28, 29, 30, 31 are also formed on the bottom so as to contact the end pocket and/or valve. The particles are then heated inductively to weld the bag. In a further embodiment, Figs. 7-10 (not shown), the upper and lower boundary edges 33, 34, 35, 36 of a piece of tubing are offset and metal particle strips 37, 38 are provided adjacent the edges 34, 35. The walls of the bag are folded over and the strips 37, 38 heated by induction. A heat-sensitive adhesive may be mixed with the metal particles and is heated by inductively heating these particles. |
