Bag packaging method

Abstract

A bag packaging method by which a mouth portion of a thin plastic-made bag filled with articles can be sealed without creases is provided. While a bag 4 filled with articles is conveyed by a blade conveyor 6, at position opposed to a sirocco fan 13, air is blown from the sirocco fan 13 toward a mouth of the bag so that the mouth portion of the bag 4 is opened. Two mouth spreader bars 20 are moved to position in front of the bag 4 so opened. The mouth spreader bars 20 having an interval between them narrowed are inserted into the bag 4. Then, the mouth spreader bars 20 have the interval widened and are retracted. Thereby, the mouth portion is spread flat. Narrowing and widening of the mouth spreader bars 20 are done by cam followers 24 engaging with different cams while moving forward and backward. The mouth portion of the bag 4 spread flat is pinched and sealed by a sealer without generation of creases and folded and bound by a binder 60.

1 . A bag packaging method comprising the steps of: 
 while conveying a bag filled with articles and placed on a carrier conveyor, blowing air toward a mouth of said bag to thereby open a mouth portion of said bag,    causing two mouth spreader bars to have an interval between them narrowed by a cam follower, provided on each of said mouth spreader bars, engaging with a cam,    inserting said mouth spreader bars having the interval so narrowed into said bag having the mouth so opened,    causing said mouth spreader bars to have the interval laterally widened by said cam follower engaging with another cam to thereby spread the mouth portion of said bag flat,    retracting said mouth spreader bars having the interval so widened, and then    causing a sealer to pinch and seal the mouth portion of said bag so spread flat.    
   
   
       2 . A bag packaging method as claimed in  claim 1 , comprising the steps of: 
 causing an air squeezer to push the mouth portion of said bag so spread flat by said mouth spreader bars,    moving said bag relative to said air squeezer by the retraction of said mouth spreader bars to thereby cause said air squeezer to squeeze air existing between the mouth of said bag and the articles filled in said bag to be discharged outside, and then    carrying out the sealing of the mouth portion of said bag.    
   
   
       3 . A bag packaging method as claimed in  claim 2 , comprising the step of: 
 carrying out the movement of said bag relative to said air squeezer by the retraction of said mouth spreader bars as well as by pushing out a bottom portion of said bag to thereby carry out the discharge of said air.    
   
   
       4 . A bag packaging method as claimed in  claim 1 , comprising the steps of: 
 inserting an air suction pipe together with said two mouth spreader bars into said bag having the mouth so opened,    causing said air suction pipe to suck out air in said bag having the mouth portion so spread flat by said mouth spreader bars to be discharged outside, and then    carrying out the sealing of the mouth portion of said bag having the air so discharged outside.