| 摘要 |
Single-layer and multi-layer block ended bags are produced by a method comprising conveying a flat web 1 of foldable material, sticking separate strips 14 of foldable material to it at intervals, forming the web into a flat bag tube 8 with the strips 14 inside, cutting the tube into bag lengths adjacent the strips 14 and opening out the bottom of each bag length by folding its wall inwardly into gussets 19, 20 and turning the gussets outwardly to form lateral turnovers 21 which are glued in the areas shown by the cross-hatching and then folded inwardly along lines 23, 24 into overlapping relation upon themselves. Each strip 14 forms a reinforcing and sealing band 14'' which is incorporated in the gussets and the lateral turnovers and assists in sealing the bottom of the bag to prevent the escape of powdery material. Various modifications include double ended bags having valved upper ends for filling, constructed on the same principle. <IMAGE> |
