Patent GB-1443339-A (GB)
Title: Method and apparatus for manufacturing bags with an inner bag which has a z-fold
IPC: B31B70/00
Filed: 1973-08-28
Abstract: 1443339 Making lined bags WINDMOLLER & HOLSCHER 28 Aug 1973 [12 Sept 1972] 40397/73 Heading B5D A method for making bags, each comprising an outer bag section AS and an inner bag ES which has a Z-fold, comprises conveying inner bag sections ES which each have a transverse base weld S, or a continuous tubular web which has been transversely welded at spaced intervals to define the inner bag bases, out of a horizontal conveying direction b1 into a slightly rising conveying direction b2 during the formation of Z-folds therein, turning the folded inner bags ES or the folded tubular web to move in a direction a2 which is opposite the direction b2, depositing them/it on a single or multiply web A for the outer bag sections AS and tubing the web A about the inner bags or the tubular web. An apparatus for performing the method comprises a double belt conveyer 5 which is located downstream of means for producing the bottom seam welds and conveys the inner bag sections ES or the tubular web horizontally and at a greater speed than the speed of the web A, axially spaced guide rollers 15 for lower belts of the conveyer 5 being movable towards and away from an inclined double belt conveyer 6 which conveys the inner bags ES or tubular web at the same speed as that of the web A and which turns the inner bags ES or tubular web to deposit them or it on the web A, axially spaced rollers 10 aligned with the guide rollers 15 and movable towards and away from the lower belt(s) of the second conveyer 6, and a folding blade 8 having folding fingers movable forwardly and backwardly between the guide rollers 15. In operation as the inner bag material is transferred from the conveyer 5 to the conveyer 6, a loop d is formed in the gap between the conveyers and as the trailing end of a bag length or an inner bag section approaches the gap, the belt guide rollers 15 and the folding blade 8 move forward, Fig. 4 (not shown), to produce the Z-fold in co-operation with the rollers 10 which may be driven and which are moved downwardly to grip the folded inner bag material. The guide rollers 15 and the folding blade 8 may remain in their forward positions to guide the leading end of the following inner bag section into the conveyer, Fig. 5 (not shown), Alternatively they may be withdrawn and then moved forwards to co-operate with the rollers 10 which are moved downwardly once more, to fold the leading end portions of the following inner bag section through 180 degrees, Figs. 6 and 7 (not shown). The formation of the loop d may be assisted by an air stream from a nozzle 17 and/or a weighting bar (51), Figs. 8 and 9 (not shown), mounted on pivoted arms (52), Figs. 8 and 9 (not shown). The apparatus may further include a braking member (59), Figs. 8 (not shown) pivotally mounted so that it can be applied from above, during a desired operating period, on to a tubular web of inner bag material supported by the first conveyer 5. Guide rods (61), Figs. 8 and 9 (not shown), may be arranged above the conveyer path between the two conveyers 5 and 6.