| 摘要 |
Handle bags are made from an elongated synthetic-resin tube having two longitudinal rows of indicia spaced apart in each row by a bag width and with the indicia of one row staggered equidistant between the indicia of the other row. The tube is passed step-wise over a cutting drum formed with an endless circumferentially extending and undulating cutting groove in which a blade engaged inwardly so that an undulating cut is formed longitudinally along the tube separating it into two tube halves which are then passed through a closeable transverse welder. One of the halves is deflected between the drum and the welder through detours dimensioned to put the flaps of the two bag halves in exact transverse alignment with one another. Each transport step is ended when the center of the indicia immediately upstream of the welder is spaced from the welder by a distance equal to half of the bag width and at this time the welder is closed on the tube to form bag-edge seams. The drum is also operated in rotary steps, but each rotary step is stopped after one full revolution of the drum about the drum axis. The rotation rate of the drum is set so that one back-and-forth motion of the blade is effected by the groove in the cutting drum each time the tube is advanced over it by a distance equal to one bag width. |
