Method and apparatus for making zipper bags
OwnerJames R. Johnsoninventor
Life of this patent
Estimating the term…
Abstract
A method and apparatus for attaching heavy weight plastic zippers to light weight plastic bag material. The method includes the steps of aligning the zippers with the bag material and holding the zippers and bag material between a pair of belts. The motion of the bag material drives the pair of belts at the same speed. Heated rails are pressed lightly against one of the belts so that heat passes through the belt and heats the bag material and zipper material only enough to seal the back of the bag material to the back zipper piece. The bag material is then held over a roll, and heated air is directed along a line to heat only the front piece of the bag material and the front zipper piece enough to seal. The bag material is then slit in the middle, and side sealed and cut by conventional means.
Claims9
A method for making plastic bags having zipper closures, wherein said bags are made of a light gauge thermoplastic and said zipper closures are made of a heavy gauge thermoplastic, said method including the steps of feeding bag material along a path, said bag material including a back and opposed front pieces, feeding a first strip of zipper material along said path adjacent to one front piece and feeding a second strip of zipper material along said path adjacent to the other front piece, lifting said front pieces from said back and feeding said zipper material into position between said back and said front pieces, aligning said first strip and said second strip of zipper material with said bag material, moving said bag material with said zipper material along said path while engaging the front of said bag material with a first belt and engaging the back of said bag material with a second belt, holding sealing rails against said second belt while heating said sealing rails sufficiently to seal said back to said zipper material, further feeding said bag material along said path, directing air against the front piece of said bag material, and heating said air sufficiently to seal said front piece to said zipper material, slitting said bag material longitudinally, and sealing transverse lines across said bag material to side seal and separate bags from said bag material.
A method for making a plastic bag having a zipper closure, wherein said bag is made of a light gauge thermoplastic and said zipper is made of a heavy gauge thermoplastic, said method including the steps of placing said zipper between the front piece of said bag and the back of said bag in position to form said zipper closure for said bag, holding the top of said bag with said zipper between a pair of belts, moving said belts while holding sealing rails against one of said belts, said sealing rails being located to seal said zipper to the back of said bag, and adjusting the heat so that said zipper is sealed to the back of said bag, holding said bag while directing heated air against said bag along a line for sealing said front piece of said bag to said zipper, and sealing the sides of said bag.
Apparatus for making zipper bags wherein the zippers are made of heavy gauge plastic and the bags are of light gauge plastic, said bags being formed from bag material having a back piece and opposed front pieces, said apparatus including means for feeding said bag material along a path, means for lifting said opposed front pieces from said back piece, means for feeding zipper material between said opposed front pieces and said back piece, aligning means for aligning said zipper material with respect to said opposed front pieces, back sealing means for sealing said back piece to said zipper material, said back sealing means comprising a plurality of sealing rails, a belt movable over said sealing rails and engaging said back piece of said bag material and movable with said bag material, means for heating said sealing rails, a second belt engaging said opposed front pieces of said bag material and movable with said bag material for holding said bag material against said belt and for urging said belt against said sealing rails, and means for sealing said front piece to said zipper material.
Dependencies are inferred from the claim text.