| 摘要 |
767,610. Making bags. WINDMOLLER, A., and HOLSCHER, F. June 25, 1954 [July 2, 1953], No. 18768/54. Class 94(2). In a machine for making bags from a seamless tube of thermoplastic film, the tube 1 is continuously fed from a supply roll by feed rolls 2, 3, driven from a wheel 6 on a shaft 5 through an arrangement 8 which enables the rate of tube feed to be accurately adjusted, whereby during each revolution of the wheel 6 two bag lengths of the tube 1 are delivered into a loop 4 around a rotatably mounted drum 26. The wheel 6 may be replaced by one of different circumference to produce bags of different length. The tube is withdrawn from the loop 4 by intermittently operating feed rolls 9, 10 and 11, 12, which are driven from the shaft 5 through a crank rod 14 and a toothed segment 17 which is mounted for oscillation about a pivot 16. The segment 17 through a ratchet drive 20 rotates a gear 21 to drive the feed rolls 9, 11, through friction couplings 24, 25. The crank pins 13 and 15 are adjustable. When the tube is at rest it is transversely heat-sealed by members 27, 28 at intervals equal to twice the length of a bag. The cutting device 29, 30, is arranged to sever the web transversely in the middle of the weld during the stationary period of the web, and centrally between each succeeding weld during the advancement of the web. To adjust for different bag lengths, the cutting and feeding arrangements 29, 30, and 11, 12, form a common slidable unit 36, the drive to those members also being adjustable. Two or more welding devices separated from each other by double the length of a bag may be provided and the machine may be made sufficiently wide to take two or more webs running side by side. |
