Heat sealing jaw assembly

A method of forming a heat seal between juxtaposed heat sealable sheet materials, said method comprising the steps of:

• (i) providing a pair of metal jaw members having heating means for heating same to a desirable temperature, each said jaw member having an end face with said end jaws disposed in facial alignment, means to reciprocate said jaws towards and away from one another,
• (ii) providing a heat conductive sealing member of soft rubber-like material along at least a common section of each said end faces in contact therewith to conduct heat from said jaw members to a fusing temperature to melt said heat sealable sheet materials,
• (iii) displacing said jaw members towards one another to press said heat conductive sealing members against said juxtaposed heat sealable sheet material from opposed sides of said sheet material and with said heat conductive sealing members in planar alignment with one another to fuse said materials and seal them together along a seal line, and
• (iv) applying an electrical pulse to a metal slitting wire, secured forwardly and substantially centrally along one of said heat conducting sealing members, and at a predetermined time during said fusing step to slit said juxtaposed sheet materials substantially centrally of said seal line.