Method and apparatus for folding and bonding a closing seal part of box-shaped package

Abstract

A method and apparatus for folding and bonding a closing seal part of a box-shaped package comprising the steps and corresponding members of folding a strip-shaped closing part of the package on an intermittently running conveyor, preheating outer surfaces of the package beneath said both-side overhanging portions into semi-weldable state, folding said overhanging portions along both outer sides of the package, pressing the folded strip-shaped closing seal portion against upper surface of the package without generating any gap therebetween and heat pressing the folded overhanging portions from outsides; and folding said both-sided overhanging portions during transfer and just before the stop position for heat pressing from outside.

What is claimed is:  
     
         1 . A method for folding and bonding a closing seal part of a box-shaped package comprising the steps of, 
 placing the package made of heat-weldable synthetic resin on an intermittently running conveyor, with top end thereof being opened;    filling a preset number of contents in the package on said conveyor sequentially;    butt-welding an upper opening of thus filled package into a strip shape with overhanging portions on both sides to form a strip-shaped closing seal part with said overhanging portions;    folding down said strip-shaped closing seal portion to one side;    preheating outer sides of said package beneath said both-side overhanging portions; and    folding said both-side overhanging portions along said preheated areas on outer sides of the package to weld inside of said overhanging portions onto the outer surfaces of said package.    
     
     
         2 . A method as set forth in  claim 1 , wherein said both-side overhanging portions are folded against the outer sides of said package and then heat-pressed from outsides of said overhanging portions to weld insides of said overhanging portions onto the outer sides of said package.  
     
     
         3 . A method as set forth in  claim 1  or  2 , wherein said folded strip-shaped closing seal part on upper part of said package is pressed against the upper surface of said box-shaped package without any gap and said both-side overhanging portions are folded against outer sides of said package to weld insides thereof.  
     
     
         4 . A method as set forth in any one of  claims 1  to  3 , wherein each process starting with filling of the contents except for the process for folding said both-side overhanging portions along said preheated areas of the outer sides of the package is carried out during rests of intermittent operation, said filling process being carried out just before intermittent stopping of the conveyer to heat press the overhanging portions from outside at the first.  
     
     
         5 . An apparatus for folding and bonding a closing seal part of a box-shaped package comprising, 
 an intermittently running conveyor for transferring the package made of heat-weldable synthetic resin and placed thereon;    means for forming a strip-shaped closing seal part with overhanging portions on both sides by butt-closing an upper opening of said package;    means for folding said closing seal part to one side;    means for preheating outer sides of said package beneath said both-side overhanging portions; and    means for folding said both-side overhanging portions onto the preheated areas on outer sides of said package to weld insides of said overhanging portions to outer sides of said package.    
     
     
         6 . An apparatus as set forth in  claim 5 , comprising means for heat pressing said both-side folded overhanging portions onto outer sides of said package to weld insides of said portions.  
     
     
         7 . An apparatus as set forth in  claim 5  or  6 , comprising means for pressing said folded strip-shaped closing seal part of said package against upper surface of said package without generating any gap.  
     
     
         8 . An apparatus as set forth in any one of claims  5  through  7 , wherein said means for folding said both-sided overhanging portions along outer sides of said package is operated in a travel section on the conveyor and just before the process for heat pressing said both side folded overhanging portions from outside at the first.