GB492741A - Improvements in and relating to methods of making paper bags and apparatus therefor - Google Patents

Abstract

492,741. Making paper bags. GODER, M. Dec. 24, 1936, No. 35445. [A Specification was laid open to inspection under Sect. 91 of the Acts, Sept. 11, 1937.] [Class 94 (ii)] In a method of making cross-bottom multi-ply paper bags by severing at least some of the plies of paper 1, 2, 3 from webs and superimposing at least some of the cut sheets in overlapping relationship to form a blank which is folded to tubular form along lines 7, 8 running transversely to the direction of travel, the plies are all the same width and the outer ply is also stopped transversely at 4 to provide a strip which is folded over and gummed down at 5 to reinforce the filling opening. The reinforcing strip may, alternatively, be severed from an additional narrow web and applied to the edge of the multi-ply blank. Creases 6, 7 and 8 are formed in the blank which, after gumming at 10, 11, 12 and folding on the lines 7, 8, is folded into the square and gummed at 17, the bottom corners 18, 19 being folded over to complete the bag. Mechanism for making a modified form of bag comprises rolls 30, 31 for feeding webs 21, 22 past a gumming device 25, 29, the two webs being thereby gummed together, a double sheet being severed therefrom at 34, 35, which is forwarded to stops 37. Meanwhile, the top sheet of an adjustable stack 38, which is to form the outer ply a<1> of the bag, is lifted by a suction device 40, gummed on the edge a by a gumming device 45 and forwarded to the double sheet resting at the stops 37, the edge a being turned over by a folding-plate and gummed down to reinforce the mouth opening of the bag. Grippers 54 on the roller 55 now convey the blank forward, the same being creased by rails 56<1>, 57, which co-operate with members 59, 60 on the roller 58, the forward edge being folded back by the roller 62. This folded leading edge then enters a guide 65, adhesive being applied to the rear edge by a gumming device 66, which is then folded over by passage between the rollers 58, 70, whereby the rear edge becomes the leading edge. Preliminary bottom-forming creases are made by the rollers 72, 73 and 74, 75, the bottom being raised inwardly through 90‹ by a roller 81 and formed into the square by a suction roll 83, a guide 82 and a suction pusher 85. A gumming device 94 gums the bottom square, and folding-blades 102 turn over the bottom corners. Cover sheets for the bottom are removed from a stack 104 by a suction device 103 and fed by a suction roller 106 past a gumming device 107 and pressed on to the bag bottom at 111. The finished bags are then conveyed by belts 113, 114 to be stacked at 120.