Twin wicketing bag machine

A bag making machine having a serrating apparatus for serrating a plurality of previously mechanically manipulated and stacked layers of dual bags made from a thermoplastic web material, the bags having stacking holes, the improvement comprising:

• pin means for receiving individual dual bags through the stacking holes therein for stationarily supporting the plurality of layers of dual bags in a stack,
• manipulating, stacking, and conveying means for conveying the individual dual bags to the pin means,
• means for serrating the stack of dual bags along spaced parallel lines while disposed on the pin means,
• means for mounting said serrating means downstream of said manipulating, stacking and conveying means, said mounting means including a holder carrying said serrating means,
• means connected to said holder for reciprocating said serrating means to penetrate all layers of the stack of dual bags mounted on the pin means to effect the parallel lines of serrations, said reciprocating means being operative to withdraw said serrating means after the serration is effected, means for heating said serrating means to a temperature below the melting temperature of said thermoplastic web material to thereby facilitate penetration of the stack of dual bags without joining the stack of dual bags,
• said serrating means comprising an elongate flat blade-like member clamped to a recess formed in said holder and provided with a series of slots interrupting the leading sharpened edge thereof to thereby produce a series of incisions and uncut bond portions being sufficiently weak to allow easy separation of individual bags from the stack of dual bags selectively along the parallel lines of serrations.

An improved bag making machine for manufacturing bags from a thermoplastic web material comprising a rotary transfer device for use in grasping and transferring non-perforated web segments successively from a pickup station on to a stacking station, the stacking station including an intermittently operating endless conveyor carrying a plurality of longitudinally spaced apart stacking devices having sets of stacking pins for use in impaling successive non-perforated web segments deposited thereon through complementary holes provided in a median strip of each non-perforated web segment, the conveyor intermittently positioning each successive empty stacking device in the path of the rotary transfer device and concurrently moving the immediate filled stacking device containing a layer of predetermined number of stacked non-perforated web segments impaled on the stacking pins upstream out of the path of the rotary transfer device to a perforating station, the perforating station including a perforating apparatus having a pair of perforating knives positioned above the stacking device filled with non-perforated segments impaled on the stacking pins moved by the conveyor from the stacking station to the perforating station, means for moving the pair of perforating knives downwardly and piercing the layer of stacked web segments and forming two parallel lines of perforations extending longitudinally with respect to the movement of the conveyor and spaced laterally outwardly from the stacking pins and defining a stack of non-severed siamese bags impaled on laterally opposite outward sides of the stacking pins.

Bag making apparatus for producing plastic bags from web segments, each web segment of a predetermined size dimensioned to form dual bags for producing two individual bags, said apparatus comprising elongate upstanding members arranged to hold a plurality of layers of non-serrated dual bags made from the web segments as a stack, serrating means for producing two parallel, spaced lines of serrations in the stack of dual bags, characterized in that the serrating means is located so that the serration operation is effected on the stack of dual bags while held in registry by said upstanding members, producing a stack of serrated non-severed dual bags held by said upstanding members;

• and that there is means operable on each non-serrated dual bag for providing each non-serrated dual bag with at least two apertures located adjacent to and on either side of the median, considered in the longitudinal direction of the web segment, of each formed non-serrated dual bag, each formed apertured and non-serrated dual bag being transferred successively to a stacking device incorporating said upstanding members on which the successive apertured and non-serrated dual bags are collected and stacked in a layer, the upstanding members extending through the apertures in the layer of the stacked non-serrated dual bags;
• and that the serrating means are operative while the stacked layer of non-serrated dual bags is retained on said upstanding members of said stacking device for producing parallel lines of serrations enabling subsequent division of each dual bag along the lines of serrations to define two individual bags.