Patent GB-784932-A (GB)
Title: Improvements in or relating to machines for the manufacture of paper or like bags
IPC: B31B29/00
Filed: 1953-01-08
Abstract: 784,932. Making paper bags. PELLETER, L. A. Jan. 8, 1953 [Jan. 10, 1952 : Dec. 29, 1952], No. 582/53. Class 94(2). In a machine for making block-bottomed paper bags the tube sections 124, Fig. 4, which may have side bellows, are fed to a continuously rotating drum by endless belts 27 and 34, the receiving members for the tube sections com-, prising sets of radial arms 36, 36a, 37, 37a, provided with shoes 62 of rubber or the like Fig. 6, which are pivoted at 43, 39, respectively, on a hub 41 secured to a shaft 64, and which together constitute the drum. The arms 37 are provided with lever arms 44 carrying rollers 46 which co-operate with a cam contour 47, and the arms 36 have lever arms with rollers 50 cooperating with a cam contour 51. The contours 47, 51 are formed by annular grooves 52, 57 respectively, in discs 53, 54, which are secured on sleeves 55, 56, respectively, the sleeves carrying ball bearings 66 which support the shaft 64 which is driven by a pinion 65. The sleeves are prevented from rotating by flanges 67, 68, secured to the framework 69, 70, of the machine. Threaded sockets 72, 73 are screwed on to the sleeves 55, 56, respectively, plates 75, 76, being attached to the sockets, which also carry through ball bearings 79, freely rotating flanges 77, 78, which are slidably connected by pins 111 to members 61, rotating with the hub 41. Sets of teeth 80 on the plates 75, 76 co-operate with pinions 81, 82 on a shaft 83, which is controlled by a wheel 84 to adjust for different bag widths. Fingers 85, Figs. 6 and 8, on the flanges 77, 78 carry members 86 housing rollers 87 which cooperate with cams 88, 89 secured to annular members 90, 91, mounted through ball bearings 92 on a shoulder on the plates 75, 76. To prevent the members 90, 91 from turning, lugs 94 are attached to a cross-stay 71 of the framework of the machine. The discs 77, 78 are provided with slide blocks 100 carrying rollers 98 which co-operate with cams 96, 97 on the members 90, 91, the blocks 100 being connected by ball and socket joints to rods 104, 105, connected by ball and socket joints to wedgeshaped members 108 mounted on spindles 109 in the members 86. The sleeve 56, Fig. 6, is provided with channels 112, 112a, which communicate through a rotating joint with channels 113 in the hub 41, the channel 112 being connected with a suction pump and the channel 112a with a blower. At the position I, Figs. 4 and 5, the arms 36, 37, are open and the bag length is fed in until it reaches an adjustable stop 120, leaving a portion of tube protruding from the drum to form the bag bottom. The wedge members 108 are also moved apart to allow the passage of the bag element. In position Ia the bag element is gripped by the arms 36, 37 and the wedges 108 are moved upwardly about their spindles 109. At the position II the arms 36, 37 move apart and suction cups 118, 119 are connected through pipes 116, 117 to the channel 112, to partially open the bag element, the wedges 108 moving in so that their points press against the bellows folds 28, 29, Fig. 19. During the movement to position IIa the wedges 108 move back about their spindles 109 to their original position, and the arms 36, 37 again move together to grip the bag, and define creases 126 to 130 the protruding bag bottom being brought between two converging guides 131, 132, which at the position IIa have a relatively large spacing from the drum, and at their other end are close to the drum. At the position III the bag element is brought under a rotating device, Figs. 11 to 16 (not shown) carrying three pairs of shoes 159 of rubber or the like, for opening the bag bottom, the speed of the shoes being higher than that of the bag so that they enter the bag bottom. The pairs of shoes 159 are then gradually delayed until they reach the same speed as the bag bottom, when they are moved laterally apart, at position IIIa to press the creases 130. Beyond the position IIIa the shoes are accelerated and the pairs of shoes move closer to each other, the front face of the shoes pressing the front face of the bag element at 188, position IV, and the sides 185, 186, being moved closer to each other by the converging guides 131, 132. A pair of spaced parallel rotating discs 189 are mounted at position IV and have a peripheral speed higher than that of the bag element so that a notch 190 in the discs engages the bag bottom to form the front point 195. During the movement to position IVa the discs 189 guide the edges 196, 197 of the bag bottom which are simultaneously bent by the guides 131, 132, thus defining the rear point 198. Between positions IVa and V a rotating marking device 199, moving at the same speed as the bag bottom, marks the creases 208, the front crease 209, and the rear crease 210, the wedges 108 moving away from the bag at position V, and at position VI being returned to their previous position. At this position a cylinder 212 applies glue stripes 213, 214, from a tank 216. When the bag reaches position VII a cam-operated arm 224 on a rotating member 218, Figs. 17 and 18 (not shown) moves under the rear flap 239 of the bag bottom, and a cam-operated resilient blade 233 on member 218 slides over the bottom of the bag and is then retarded so that the free end of the blade remains adjacent the crease 210. The arm 224 then folds over the rear flap on to the glue stripes 213, 214, the blade 233 being rapidly withdrawn. The second set of arms 224 and blades 233 is used on the following bag. At position VIII the bag is brought under a rotating member carrying blades 241, 242, the ends of which move at not more than half the speed of the bag, and which make first an obtuse angle and then an acute angle with the bag bottom. In this way the front point 195 of the bag is lifted and then the flap 243 is folded back over the flap 239. The bag then passes under a bar 244, which holds the flaps in place, to position IX where it passes under a curved rod 245 and the flaps are pressed by a rotating cylinder 246 provided with resilient projections 247. At position X the wedges 108 commence to move away from the bag and at position XI the wedges are removed from the bag, the bottom flaps being held in position by the rod 245. In position XII the arms 36, 37 open to release the bag and cam-operated members 251 on a rotating drum 249, which moves at a speed greater than that of the bag, pass under the bag bottom. Simultaneously the channel 113 comes opposite the channel 112a and air is blown into the channel to assist in the removal of the bag, which is carried round by the drum 249 and pressed against its periphery by a deflector 254. The finished bags are then removed by a similar drum 255 and deposited on a table 257. To make a bag without side bellows the wedge members 108 are made inoperative.