Stand up bag and method of manufacturing the same

Abstract

A method for manufacturing a stand up bag having an indented bottom wall includes the steps of forming a tube of material and sealing the end of the tube. The sealed end is then moved up with respect to the sidewall to form a downwardly-extending rim. Portions of the rim are then welded to hold the bottom wall in this position.

1 . A method of forming a bag comprising the steps of: 
 (a) providing a tube of material that will be used to form the body of the bag;    (b) closing a portion of the tube to form the bottom closure seam of the bag;    (c) indenting the bottom closure seam of the bag with respect to the tube to define a rim and a bottom wall; and    (d) welding at least one portion of the rim.    
     
     
         2 . The method of  claim 1 , further comprising the step of filling the tube with material after step (b).  
     
     
         3 . The method of  claim 2 , further comprising the step of filling the tube with material during step (c).  
     
     
         4 . The method of  claim 2 , further comprising the step of filling the tube with material during step (d).  
     
     
         5 . The method of  claim 1 , wherein step (d) includes the step of welding a plurality of spaced locations about the rim.  
     
     
         6 . The method of  claim 1 , wherein step (c) includes the steps of: 
 providing a bottom former; and    moving the bottom former up into the tube.    
     
     
         7 . The method of  claim 1 , wherein step (c) includes the steps of: 
 providing a bottom former; and    moving the tube down onto the bottom former.    
     
     
         8 . The method of  claim 1 , wherein step (c) includes the steps of: 
 providing a bottom former; and    simultaneously moving the tube down onto the bottom former and moving the bottom former up into the tube.    
     
     
         9 . The method of  claim 1 , further comprising the steps of: 
 providing a former that performs step (c); and    passing the filled tube through the former after step (d).    
     
     
         10 . The method of  claim 1 , further comprising the steps of: 
 passing the tube of material over a collar that defines a plurality of weld openings; and    welding the rim portions at the weld openings of the collar.    
     
     
         11 . A method of forming a bag comprising the steps of: 
 (a) forming a tube of weldable material having a leading end;    (b) sealing the leading end to itself to form the bottom closure seam of the bag;    (c) filling the tube with material to provide a filled tube;    (d) indenting the bottom closure seam with respect to the tube of material to define a rim and a bottom wall of the bag;    (e) welding a plurality of rim portions to create a plurality of spaced welds along the rim; and    (f) sealing another portion of the tube of material to form the top closure seam of the bag and a sealed filled bag.    
     
     
         12 . The method of  claim 11 , wherein step (d) occurs during step (c).  
     
     
         13 . The method of  claim 11 , wherein step (f) of one bag simultaneously performs step (b) for the next bag to be formed.  
     
     
         14 . The method of  claim 11 , further comprising the steps of: 
 sealing the leading end of the tube of material with a welding jaws; and    passing the filled tube through the welding jaws after step (d).    
     
     
         15 . The method of  claim 11 , further comprising the steps of: 
 passing the tube of material over a collar that defines a plurality of weld openings; and    welding the rim portions at the weld openings of the collar.    
     
     
         16 . The method of  claim 15 , further comprising the steps of: 
 providing a welder for each weld; and    moving the welder during step (e) in a direction substantially transverse to the longitudinal direction of the tube of material.    
     
     
         17 . The method of  claim 11 , further comprising the steps of: 
 providing a former that performs step (d); and    passing the filled tube through the former after step (d).    
     
     
         18 . The method of  claim 11 , wherein step (d) includes the steps of: 
 providing a bottom former; and    moving the bottom former up into the tube.    
     
     
         19 . The method of  claim 11 , wherein step (d) includes the steps of: 
 providing a bottom former; and    moving the tube down onto the bottom former.    
     
     
         20 . The method of  claim 11 , wherein step (d) includes the steps of: 
 providing a bottom former; and    simultaneously moving the tube down onto the bottom former and moving the bottom former up into the tube.