| 摘要 |
1287044 Seaming non-metallic sheet material E HARTMANN and B SEILER 30 July 1970 [26 Aug 1969] 36975/70 Heading B5K A flat tube is produced from two thermoplastic film strips 1 by intermittently drawing off the strips 1 from two supply rolls 3 by reciprocating clamping jaws 8, applying hot air to the longitudinal edge zones of the strips 1 by blowers 9 which are removed from the edge zones at each forward feed stroke of the jaws 8, and pressing the strips between rollers 6 to weld together the heated longitudinal edges. The apparatus comprises a fixed frame 13 and a vertically reciprocable frame 12. The frame 13 carries two guide pulleys 4 for the strips 1, a pipe 14 for the supply of compressed air, and a pair of clamping rollers 11 rotatable in the direction of the arrows 11b only. The frame 12 carries guide pulleys 5 for the strips 1, the pressure rollers 6 with guide plates 7, the clamping jaws 8 and the hot air blowers 9 having nozzles 10. In operation, the apparatus is set up by passing the leading ends of the strips 1 over the pulleys 4, 5, between the rollers 6, 11 and between the jaws 8. The jaws 8 are clamped together to hold the strips 1 and the frame 12 is moved downwardly to feed the strips an increment. At the lower position, the jaws 8 are opened to release the strips 1 and, simultaneously, the blowers 9 move inwardly from an outer inoperative position, Fig. 3 (not shown), to the position of Fig. 1. The longitudinal edges of the strips 1 above the rollers 6 are softened. The frame 12 moves upwardly as the heated edges are compressed by the rollers 6 and thus welded together to form a tube 2. When the frame 12 reaches its upper position, the blowers 9 are moved outwardly and the jaws 8 clamp the tube 2. Subsequent downward movement of the frame 12 feeds the strips by another increment. The tube 14 serves for inflating the tube 2 in a subsequent packaging apparatus. |
