Machine for the treatment of a web of material, for example, by thermal welding and cutting to size, in particular for the production of sacks

摘要

1,056,761. Making bags; seaming nonmetallic sheet material. TRANS-ATLAS A.G. Aug. 23, 1963 [Aug. 23, 1962], No. 33512/63. Headings B5D and B5K. [Also in Division B6] Carriers 15, Fig. 1, which grip, seal, and cut into bags a tube or longitudinally folded web are separate from the belt 19 which drives them whilst they grip the tube or web, so that their distance apart, which determines the size of the bags made, and the speed of the belt 19, which affects the rate of production, can be varied independently. Feeding webs and adjusting bag size.-Carriers 15 fed into tracks 11, 11SP1/SP, Fig. 1, by wheels 29, 29SP1/SP grip between them driving belts 19 and the web so that they are driven by the belts and carry the web along with them. The carriers return via inclined tracks 12, 12SP1/SP. Swingable gates 32, 32SP1/SP, Fig. 3, opened by a face cam 37, control feed of the carriers by wheels 29, 29SP1/SP which are spring coupled to their driving shafts to allow for any discrepancy in their synchronization with cam 37. The ratio of the speeds of wheels 29, 29SP1/SP and belts 19 determines the distance between consecutive pairs of carriers and hence the size of bags produced. The ratio is varied by a gear (not shown) and a further gear controls the speed of belts 19 whilst the ratio remains constant. When a printed web is used a photo-electric cell 63 (Fig. 5, not shown), controls further the speed of belts 19 via a known amplifier and differential 59 (Fig. 5) so that the cutting and sealing operations are performed by the carriers at the correct positions on the web. Cutting and sealing.-One or two shielded filaments 65 (Fig. 7), in each carrier 15, 15SP1/SP, heated by current picked up from a contact rail by a brush (not shown), seal the web transversely at one or two places, the length of sealing time being controlled by the length of the contact rail. Each upper carrier 151 has a knife 70 carried by a pin 69 which slides in a slot 68 extending longitudinally of the carrier (i.e. across the web) and as the carrier advances through the machine fixed camming ploughs engage the pin so that the knife is pushed across the web to cut it and then returned to its original position. Stacking of completed bags.-A pair of wings 79, Fig. 8, freely rotatable on a shaft 78 lies in a position of rest shown in dashed lines. An approaching pair of carriers 15 swings one of the wings 79 into contact with the bag 90 which it carries, and causes the wing to force the trailing edge of the bag free from the carriers and on to a belt 84. Simultaneously, the leading edge of the bag is released from the previous pair of carriers and also falls on to the belt. When a predetermined number of bags have been deposited a counter 91 energizes an electromagnetic coupling 88 so that the belt 84 is moved to deposit the stack of bags on a table 92.