Apparatus for Pulling Vertically Positioned Horizontally Traversing Plastic Film Bag Walls and Heat Fusing the Walls and Closing the Bag

Abstract

In an automated machine that forms a vertically positioned and horizontally traversing web of plastic film into bags and fills the bags with material, after the bags are filled, a pair of gripping fingers clampingly grip and pull the bag upper longitudinal edge portions into a sealing gap between a pair of heat seal bars whereat the bag walls are heat fused together and the bag is sealed closed. A pair of clamp bars below the heat seal bars clampingly engage the bag walls after they are pulled into the gap and prior to heat sealing. The filled bags are linked along their longitudinal edge portions with perforations therebetween. The bags are severed from one another at a perforation when the gripping fingers pull the bag walls into the gap. The gripping fingers are carried on and are moved longitudinally with a pair of belts located vertically above the gap.

What is claimed is: 
     
         1 . An apparatus for heat seal closing vertically positioned plastic film bags comprising a pair of plastic film walls having upper terminal longitudinal edge portions, said longitudinal edge portions being proximate and parallel to one another, said apparatus comprising:
 a pair of elongate parallel heat seal bars defining a longitudinally extending heat sealing gap therebetween and selectively moveable into said heat sealing gap adjacent one another;   a pair of gripping fingers defining a gripping gap therebetween and selectively moveable into said gripping gap adjacent one another;   wherein said gripping fingers are selectively moveable longitudinally along said longitudinally extending heat scaling gap; and,   wherein said bag terminal edge portions are placed in said gripping gap, said gripping fingers are moved adjacent one another and thereby clampingly grip said bag terminal edge portions, said gripping fingers are moved longitudinally along said heat sealing gap thereby pulling said bag walls within said heat sealing gap, and said heat seal bars are moved into said heat sealing gap engaging said bag walls therebetween whereby said bag walls are heat fused to one another and said bag is sealed closed.   
     
     
         2 . The apparatus of  claim 1  further comprising a pair of elongate parallel clamp bars vertically below said heat seal bars, each clamp bar positioned on opposite sides of said heat sealing gap and selectively moveable into said heat sealing gap adjacent one another, and wherein said clamp bars are moved adjacent one another and clampingly engage said bag walls after said bags walls are pulled into said heat sealing gap and prior to said heat seal bars engaging said bag walls. 
     
     
         3 . The apparatus of  claim 2  wherein said heat seal bars and gripping fingers are located downstream from a bag opening assembly whereat said bags are opened and filled with material. 
     
     
         4 . The apparatus of  claim 3  wherein said bags are linked to one another at their upper terminal longitudinal edge portions and a weakened attachment line is provided in the longitudinal edge portions between each bag and wherein, when said bag is pulled by said gripping fingers, said bag being pulled into said heat sealing gap is severed from an upstream bag at said weakened attachment line. 
     
     
         5 . The apparatus of  claim 4  wherein said weakened attachment line comprises a perforation. 
     
     
         6 . The apparatus of  claim 4  wherein each said gripping finger comprises a raised contact face, a raised gripping rib and a relief gap therebetween, and wherein, when said pair or gripping fingers are moved adjacent one another, said respective contact faces oppose each other, said raised gripping ribs oppose each other and said relief gaps oppose each other, and said bag terminal edge portions are clampingly gripped between said raised gripping ribs. 
     
     
         7 . The apparatus of  claim 6  wherein said gripping fingers are located vertically above said heat seal bars. 
     
     
         8 . The apparatus of  claim 6  further comprising at least one drive belt selectively moveable along said longitudinally extending heat sealing gap, and wherein said gripping fingers are carried on said belt and are thereby selectively moveable longitudinally along said longitudinally extending heat sealing gap. 
     
     
         9 . The apparatus of  claim 6  wherein a pneumatic cylinder is coupled to each of said gripping fingers and are actuated for thereby selectively moving said gripping fingers into said gripping gap adjacent one another. 
     
     
         10 . The apparatus of  claim 1  wherein said heat seal bars and gripping fingers are located downstream from a bag opening assembly whereat said bags are opened and filled with material. 
     
     
         11 . The apparatus of  claim 10  wherein said bags are linked to one another at their upper terminal longitudinal edge portions and a weakened attachment line is provided in the longitudinal edge portions between each bag and wherein, when said bag is pulled by said gripping fingers, said bag being pulled into said heat sealing gap is severed from an upstream bag at said weakened attachment line. 
     
     
         12 . The apparatus of  claim 11  wherein said weakened attachment line comprises a perforation. 
     
     
         13 . The apparatus of  claim 1  wherein said bags are linked to one another at their upper terminal longitudinal edge portions and a weakened attachment line is provided in the longitudinal edge portions between each bag and wherein, when said bag is pulled by said gripping fingers, said bag being pulled into said heat sealing gap is severed from an upstream bag at said weakened attachment line. 
     
     
         14 . The apparatus of  claim 13  wherein said weakened attachment line comprises a perforation. 
     
     
         15 . The apparatus of  claim 1  wherein said gripping fingers are located vertically above said heat seal bars. 
     
     
         16 . The apparatus of  claim 1  wherein each said gripping finger comprises a raised contact face, a raised gripping rib and a relief gap therebetween, and wherein, when said pair or gripping fingers are moved adjacent one another, said respective contact faces oppose each other, said raised gripping ribs oppose each other and said relief gaps oppose each other, and said bag terminal edge portions are clampingly gripped between said raised gripping ribs. 
     
     
         17 . The apparatus of  claim 1  further comprising at least one drive belt selectively moveable along said longitudinally extending heat sealing gap, and wherein said gripping fingers are carried on said belt and are thereby selectively moveable longitudinally along said longitudinally extending heat sealing gap. 
     
     
         18 . The apparatus of  claim 17  wherein said gripping fingers are located vertically above said heat seal bars. 
     
     
         19 . The apparatus of  claim 17  wherein each said gripping finger comprises a raised contact face, a raised gripping rib and a relief gap therebetween, and wherein, when said pair or gripping fingers are moved adjacent one another, said respective contact faces oppose each other, said raised gripping ribs oppose each other and said relief gaps oppose each other, and said bag terminal edge portions are clampingly gripped between said raised gripping ribs. 
     
     
         20 . The apparatus of  claim 1  wherein a pneumatic cylinder is coupled to each of said gripping fingers and are actuated for thereby selectively moving said gripping fingers into said gripping gap adjacent one another.