Patent GB-1332544-A (GB)
Title: Method and apparatus for forming packages of plastics bags
IPC: B31B19/94
Filed: 1971-06-03
Abstract: 1332544 Winding up chains of bags; feeding webs VERENIGDE FABRIEKEN VAN L J HEIJMEIJER NV 3 June 1971 [9 June 1970] 18855/71 Headings B8C and B8R [Also in Division B5] A continuous length of plastics bags 1<SP>1</SP> formed by transversely welding and perforating a flattened tubular web 1 (see Division B5) is wound around prongs 39 of a first rotating winding head 38 whilst passing between prongs 39 of a stationary rotatable winding head 38 spaced from the first head 38 so that only one perforated line at a time is located between the heads 38; as soon as a predetermined number of bags has been wound on the first head 38 it is braked and the second head 38 is rotated to break the length of bags 1<SP>1</SP> along a perforation between the heads 38 and to wind up a further predetermined number of bags, the first head 38 then moves to an inoperative position to strip the bags from the prongs 39, after which it returns to its operative position whereat the length of bags 1<SP>1</SP> passes between its prongs ready to wind up more bags. Each prong 39 is fixed to a cheek 40 pivotally mounted by a pin 41 in a cylindrical housing 42 which is secured to a hollow rotatable spindle 44 driven by a chain and sprocket drive 62, 63 and braked by an electromagnet brake 67. A shaft 68 slidably mounted within the hollow spindle 44 is movable by a dog 70 between the position shown in Fig. 2 where it causes the prongs to assume a spread - apart condition and a position where the prongs assume a contracted condition (Fig. 3). The spindle 44 is mounted on a slide plate 50 which is reciprocatable, in a direction parallel to the length of the prongs, between the operative position shown in Fig. 2 and the inoperative position (Fig. 3) whereat the slide plate 50 is displaced from a stop 78. A rotatable stripping ring 79  mounted on the machine frame strips the wound up bags from the prongs. A pivotally mounted change-over lever 81, and a second lever 82 pivoted to the lever 81 and carrying rolls 83, 83<SP>1</SP> co-operate with the winding heads 38 and are movable between the positions shown in full and broken lines in Fig. 6. A sprocket 84 coaxial with the pivotal axis of the change-over lever 81 is connected by a chain 85 to a second sprocket 86 fixed to the second lever 82 so that as the lever 81 is swung about its pivotal axis, the second lever 82 rotates in an opposite direction. Upon commencement of rotation of the head 38, the prongs 39 have a speed which is greater than the supply speed of the length of bags. Initially the prongs 39 are rotated at a speed higher than the supply speed of the bags, then the rotational speed of the prongs is reduced to less than the bag supply speed before becoming equal to the bag supply speed. This difference in speed is compensated by passing the web of bags around rollers 31, 31<SP>1</SP>, 31<SP>11</SP> mounted on a pivoted lever 32 and around further rollers 30, 30<SP>1</SP>, 30<SP>11</SP>, 30<SP>111</SP> mounted on the machine frame. The machine also includes an arrangement 17  for converting intermittent feed of the web as it passes through transverse welding and perforating station 4, 13 respectively into continuous feed. The arrangement 17 comprises rollers 19, 19<SP>1</SP> mounted on a pivotal lever 20, rollers 21, 21<SP>1</SP> mounted on the machine framework and a cam 26 which controls the movement of the lever 20 through a rod 23 and a lever 24 having a cam follower roller 25.