Apparatus and method for opening bags in bale enveloping apparatus

Abstract

An apparatus for separating the bag walls of preformed bags having an open end and a closed end for use in an apparatus for enveloping bales of material. The bag walls are initially adjacent one another. Vacuum and grip pin assemblies are provided on jaws which are movable between retracted and closed positions. The jaws are closed onto the bag walls and a vacuum is applied to vacuum inlet openings drawing the bag walls thereto. Preferably, the jaws are partially separated and then a grip pin is extended adjacent the vacuum inlet openings thereby piercing and securely gripping the walls. The jaws are then retracted thereby fully separating the bag walls and opening the bag. Preferably, the vacuum inlet openings are saddle shaped having a rim defining aligned raised sides and aligned lowered sides therebetween, and the grip pin extends along the aligned raised sides.

What is claimed is: 
     
         1 . In an apparatus for enveloping bales of material with preformed bags having an open end and a closed end, wherein the bags include opposing first and second elongate bag walls joined at opposing side fold edges and wherein the bag walls are provided adjacent one another at said open end, an apparatus for separating the bag walls at the open end comprising:
 upper and lower jaws, said jaws being selectively extendable to a position adjacent each other and retractable to a position wherein they are separated from each other, whereby a bag can selectively be placed between said jaws with said first bag wall adjacent one of said upper or lower jaws and said second bag wall adjacent the other of said upper or lower jaws;   a first vacuum coupling having a first vacuum inlet opening carried on said upper jaw;   a second vacuum coupling having a second vacuum inlet opening carried on said lower jaw;   a selectively extendable and retractable first grip pin adjacent said first vacuum inlet opening and a selectively extendable and retractable second grip pin adjacent said second vacuum inlet opening whereby, at each of said first and second vacuum couplings, by providing a vacuum at said vacuum inlet opening and drawing a bag wall thereto and thereafter extending the grip pin and piercing the bag wall, the bag wall can be securely gripped for thereby retracting the upper and lower jaws and separating the bag first and second walls.   
     
     
         2 . The apparatus of  claim 1  wherein said vacuum couplings, at their vacuum inlets, include a saddle shaped rim having aligned raised sides and aligned lowered sides therebetween. 
     
     
         3 . The apparatus of  claim 2  wherein said grip pins are selectively extendable and retractable along said aligned raised sides and between said aligned lowered sides. 
     
     
         4 . The apparatus of  claim 3  wherein, at each said vacuum coupling, an aperture is provided communicating with its vacuum inlet, said grip pin being selectively extendable and retractable through said aperture. 
     
     
         5 . The apparatus of  claim 4  wherein said aperture is provided, at each said vacuum coupling, generally below one of said raised sides and a depression is provided on said rim at said other one raised sides, said grip pin being selectively extendable and retractable between said aperture and said depression. 
     
     
         6 . The apparatus of  claim 5  wherein said grip pins include a sharp terminal end whereby the bag walls may be pierced. 
     
     
         7 . The apparatus of  claim 1  wherein, at each said vacuum coupling, an aperture is provided communicating with its vacuum inlet, said grip pin being selectively extendable and retractable through said aperture. 
     
     
         8 . The apparatus of  claim 7  wherein said aperture is provided, at each said vacuum coupling, generally below one of said raised sides and a depression is provided on said rim at said other one raised sides, said grip pin being selectively extendable and retractable between said aperture and said depression. 
     
     
         9 . The apparatus of  claim 8  wherein said grip pins include a sharp terminal end whereby the bag walls may be pierced. 
     
     
         10 . The apparatus of  claim 1  wherein said grip pins include a sharp terminal end whereby the bag walls may be pierced. 
     
     
         11 . In a method for enveloping bales of material with preformed bags having an open end and a closed end, wherein the bags include opposing first and second elongate bag walls joined at opposing side fold edges and wherein the bag walls are provided adjacent one another at said open end, a method of separating the bag walls at the open end comprising the steps of:
 providing a first vacuum coupling having a first vacuum inlet opening adjacent said first bag wall;   providing a second the vacuum coupling having a second vacuum inlet opening adjacent said second bag wall;   providing a vacuum at said first and second vacuum couplings and drawing said first bag wall to said first vacuum inlet opening and drawing said second bag wall to said second vacuum inlet opening;   at each of said first and second vacuum inlet openings, securely gripping said respective first and second bag walls; and,   separating said first and second vacuum couplings from one another thereby separating said first and second bag walls from one another and opening the bag for thereafter enveloping a bale.   
     
     
         12 . The method of  claim 11  wherein, prior to said step of securely gripping, said first and second vacuum couplings are first separated a short distance whereby said first and second bag walls are placed out of contact from one another. 
     
     
         13 . The method of  claim 12  wherein, during said step of securely gripping, a grip pin is extended adjacent said vacuum inlet for thereby piercing the bag wall. 
     
     
         14 . The method of  claim 13  wherein, during said step of extending said grip pin, said grip pin is extended through an aperture in said vacuum coupling. 
     
     
         15 . The method of  claim 13  wherein said vacuum couplings, at their vacuum inlets, include a saddle shaped rim having aligned raised sides and aligned lowered sides therebetween and, during said step of extending said grip pin, said grip pin is extended along said aligned raised sides and between said aligned lowered sides. 
     
     
         16 . The method of  claim 13  wherein said grip pins include a sharp terminal end and, during said step of piercing said sharp terminal end pierces the bag wall. 
     
     
         17 . The method of  claim 11  wherein, during said step of securely gripping, a grip pin is extended adjacent said vacuum inlet for thereby piercing the bag wall. 
     
     
         18 . The method of  claim 17  wherein, during said step of extending said grip pin, said grip pin is extended through an aperture in said vacuum coupling. 
     
     
         19 . The method of  claim 17  wherein said vacuum couplings, at their vacuum inlets, include a saddle shaped rim having aligned raised sides and aligned lowered sides therebetween and, during said step of extending said grip pin, said grip pin is extended along said aligned raised sides and between said aligned lowered sides.