BAG PRODUCTION METHOD Russian patent published in 1999 - IPC

FIELD: bag manufacture. SUBSTANCE: method for making bag of flattened tube comprises steps of initially folding lengthwise edges 4 of tube 1 with formation of inner folds 2; subsequently folding flattened tube with inner folds in order to reduce tube width; successively bending portions forming inner folds relative to respective bending lines 5 in such a way that to arrange them at opposite sides of tube mean portion 3 between portions forming inner folds; making cross welded seam on folded tube for forming bag bottom; between folding operations performing handle formation due to removing mean portion of folded tube with inner folds and due to performing cross welded seam on tube in position corresponding to handle ends. EFFECT: enhanced folding quality due to sustaining uniform tension along tube width. 18 cl, 10 dwg