Sealing of reclosable plastics bags
AssigneeSupreme Plastics Holding Limited
InventorMurray Edward Bruce Leighton
Life of this patent
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Abstract
A heat sealing jaw (10), particularly for use in a form-fill-seal machine for the sealing of plastics bags incorporating a zipper seal, comprises a plurality of spaced heat sealing wires (12) in its active surface and a plurality of pressure switches (13) underlying the wires. When the jaw is moved into contact with the zipper and an overlying host material the zipper imparts pressure to a switch or switches and this effects heating of a predetermined wire or wires to create the seal at the correct position. Thus, the seal is made at the correct position even if the position of the zipper on the host material should change. A pair of aligned jaws (10) are preferably used, one on each side of the host material.
Claims12
A heat sealing jaw comprising a body provided with a plurality of spaced heat sealing wires, and a plurality of pressure switches associated with the wires and operable when pressure is imparted thereto to effect heating of a predetermined wire or wires.
Apparatus for the sealing of a bag of plastics material, which comprises guide means to direct a film of plastics material along a sealing path, and at least one heat sealing jaw located adjacent to said path and displaceable into contact with the film, said heat sealing jaw comprising a body provided with a plurality of spaced heat sealing wires, and a plurality of pressure switches associated with the wires and operable when pressure is imparted thereto to effect heating of a predetermined wire or wires.
A method of sealing a bag in a form-fill-seal machine, which comprises positioning lengths of zipper strip at intervals along a movable film of plastics material, forming and filling the bag material, and guiding the formed and filled bag material into a sealing path on opposite sides of which is located a first pair of heat sealing jaws for effecting a top seal of the bag and a second pair of sealing jaws for effecting sealing of the film to the zipper strip, at least one of said second pair of jaws being a heat sealing jaw comprising a body provided with a plurality of spaced heat sealing wires, and a plurality of pressure switches associated with the wires and operable when pressure is imparted thereto to effect heating of a predetermined wire or wires.
Dependencies are inferred from the claim text.