Plastic Film Tabs and Loops Supporting Method and Apparatus

Abstract

Apparatus for vertically supporting and guiding a web of plastic film horizontally in applications such as in machines that form the plastic film into bags and fill the bags with bulk material. A longitudinally extending gap is provided between proximate edges of first and second plates. The plastic film web is traversed through the gap. A punch mechanism forms protrusions in the web. The protrusions slide atop the plates and prevent the web from falling through the gap as the web traverses through the gap. The protrusions can, for example, be tab cutouts with terminal ends sliding atop the plates and loops formed between slits extending to a crest.

What is claimed is: 
     
         1 . A plastic film web supporting and guiding assembly comprising:
 a first plate having a longitudinal edge;   a second plate having a longitudinal edge;   the longitudinal edges of the first and second plates located proximate each other a form a longitudinal gap therebetween extending from an upstream gap opening to a downstream gap opening;   a plastic film web traversing through the longitudinal gap from the upstream gap opening to the downstream gap opening;   a punch mechanism adapted to selectively extend a punch finger into the plastic film web and thereby form a protrusion; and,   wherein the plastic film web and protrusion together are thicker than the gap and the protrusion slides atop one of the plates as the plastic film web traverses through the gap, whereby the plastic film web is supported and guided through the gap.   
     
     
         2 . The assembly of  claim 1  wherein the protrusion is a tab cutout having a terminal end and wherein the terminal end of the tab cutout slides atop one of the plates. 
     
     
         3 . The assembly of  claim 1  wherein the protrusion is a loop formed between slits extending to a crest and wherein the loop slides atop one of the plates. 
     
     
         4 . The assembly of  claim 1  wherein the punch mechanism includes a plurality of punch fingers whereby a plurality of longitudinally aligned protrusions are formed. 
     
     
         5 . The assembly of  claim 4  wherein the protrusions are tab cutouts having a terminal end, and wherein the tern . ends of the tab cutouts slide atop one of the plates. 
     
     
         6 . The assembly of  claim 4  wherein the protrusions are loops formed between slits extending to a crest and wherein the loops slide atop one of the plates. 
     
     
         7 . The assembly of  claim 1  wherein the punch mechanism is adapted to selectively extend a first plurality f punch finger into the plastic film web and thereby form a plurality of protrusions proximate the first plate and is adapted to selectively extend a second plurality of punch fingers into the plastic film web and thereby form a plurality of protrusions proximate the second plate. 
     
     
         8 . The assembly of  claim 7  wherein the protrusions are tab cutouts having a terminal end, and wherein the terminal ends of the tab cutouts slide atop the plates. 
     
     
         9 . The assembly of  claim 7  wherein the protrusions are loops formed between slits extending to a crest and wherein the loops slide atop the plates. 
     
     
         10 . A method of supporting and guiding a plastic film web comprising:
 providing a first plate having a longitudinal edge;   providing a second plate having a longitudinal edge;   locating the longitudinal edges of the first and second plates proximate each other a forming a longitudinal gap therebetween extending from an upstream gap opening to a downstream gap opening;   traversing the plastic film web through the longitudinal gap from the upstream gap opening to the downstream gap opening;   creating a protrusion in the plastic film web wherein the plastic film web and protrusion together are thicker than the gap; and   preventing the plastic film web from falling through the gap with the protrusion sliding atop one of the plates while the plastic film web is traversed through the gap.   
     
     
         11 . The method of  claim 10  wherein the step of creating comprises forming a tab cutout having a terminal end and wherein the terminal end of the tab cutout slides atop of the plates. 
     
     
         12 . The method of  claim 10  wherein the step of creating comprises forming a loop between slits extending to a crest and wherein the loop slides atop one of the plates. 
     
     
         13 . The method of  claim 10  wherein the step of creating comprises creating a plurality of longitudinally aligned protrusions. 
     
     
         14 . The method of  claim 13  wherein the step of creating comprises forming a plurality of tab cutouts having a terminal end and wherein the terminal ends of the tab cutouts slide atop one of the plates. 
     
     
         15 . The method of  claim 13  wherein the step of creating comprises forming a plurality of loops between slits extending to a crest and wherein the loops slide atop one of the plates. 
     
     
         16 . The method of  claim 10  wherein the step of creating comprises creating a plurality of protrusions proximate the first plate and a plurality of protrusions proximate the second plate. 
     
     
         17 . The method of  claim 16  wherein the step of creating comprises forming a plurality of tab cutouts having a terminal end, and wherein the terminal ends of the tab cutouts slide atop the plates. 
     
     
         18 . The method of  claim 16  wherein the step of creating comprises forming a plurality of loops between slits extending to a crest and wherein the loops slide atop the plates.