GB191211219A - An Improved Machine for Making Bags, Envelopes or the like of Paper or other Materials. - Google Patents

Abstract

11,219. Barnett, H. A. May 11. Paper bags, envelopes, and the like, making.- Relates to a machine for making flat paper bags or envelopes in which the feed - rolls, folding- devices, &c. are arranged in a vertical plane. The invention consists chiefly in the use of a device to compensate for the loss of weight in the pile of blanks, and also in the use of tapering plates to stretch the paper in order to make the side flaps lie flat after folding. A pile f, Fig. 1, of cut blanks, of the shape shown in Fig. 20, is placed on a table e, which is drawn upwards by a counterweight w so that the top of the pile is constantly pressed against a pair of feeding and folding rollers 7, 10, Figs. 1 and 8 In order to compensate for the loss of weight of the pile as the blanks are abstracted, and thus to maintain a constant pressure between the top of the pile and the feed-rollers, the table c has a depending tapering rod 5, Fig. 1, which passes through holes in the centre of a number of metal disks 6 which normally rest in a pile on a shelf 4. The hole in each disk is slightly larger than that in the disk immediately above it, so that, as the pile of blanks diminishes, the table e moves upwards and the rod 5 picks up the disks one at a time, thus compensating for the loss of weight of the pile of blanks. The rollers 7, 10, Fig. 8, against which the top blank is pressed, rotate in the directions shown by the arrows and gather the blank between them, thus folding it across the line A-B, Fig. 20, and feeding it to a series of rollers 38, 41 which convey it past the gumming and folding devices. The roller 7 is preferably made of steel and is polished, and the roller 10 is preferably made of rubber. In a modified construction, instead of being of steel and rubber, respectively, the rollers 7, 10 are made hollow with a longitudinal slot coirimunicating with the central hollow portion. The gearing of an air-pump connected with the rollers is so arranged that the blank is held by suction against the rollers while it is being gathered, but is blown away from them when its central fold is gripped between the rollers. The blank thus folded about its middle has the side flaps 14, Fig. 20, extended, and these are gummed by wheels which dip into gum troughs and press the flaps into grooves 18 on a roller 17, Figs. 1 and 8. The blank is next carried by means of the rollers 38, 41 past the device for folding or turning over the gummed flaps. The rollers 38 are positively driven while the rollers 41 are freely mounted on fixed shafts and are pressed into contact with the rollers 38 by springs. The rollers 41 are arranged in two sets, as shown in Fig. 1, and are mounted in two frames 45 which can be moved relatively to one another by means of screws 54 and locked in position by bolts 51. Secured to each frame 45 is a plate 58, and inclined strips 61 are attached to the frame 45 in front of the edge of the plate 58. As the blank is carried upwards by the rollers, the gummed flaps are engaged by the strips 61 and turned over the edges of the plates 58. The edges of the plates 58 diverge from the bottom to the top so that the gummed flaps are first folded over and are then drawn apart or stretched until they are finally pressed down on to the body of the bag by rollers 65. The finished bag is then fed either into a collecting- device or to a printing-machine. By reason of the rollers being mounted in two sets, the distance between the plates 58 can be adjusted to suit different sizes of blanks. In order to ensure that each of the blanks is removed from be tween the rollers 7, 10, before the next one is gripped by them, these rollers are driven at a slower speed than the rollers 38 and the rubber roller 10 is driven by a lug on a gear-wheel which engages a stop on the roller. Thus when the folded blank passes from between the rollers 7, 10 it is gripped by the faster-running feedrollers, which cause the roller 10 to turn in advance of its driving-lug while the blank slips over the polished roller 7. The roll 10 then rests until the driving-lug re-engages it and causes it to feed the next blank.