Bag tying machine

Abstract

The sealing of plastic bags filled with a particular product, for example bread, is commonly achieved by folding a length of adhesive tape ( 1 ) around the gathered neck ( 10 ) of the bag. The adhesive tape ( 1 ) is folded such that the ends of the tape stick to each other to form a closed loop. A bag tying machine for sealing bags in this way includes a roll of adhesive tape ( 1 ) having spaced portions ( 3 ) which are non-adhesive, wherein the tape is wholly coated with adhesive and the non-adhesive portions are portions which have been treated to neutralise the adhesive; a detector ( 14 ) for detecting the boundary between the adhesive and non-adhesive portions of the adhesive tape ( 1 ); and, cutting means ( 13 ) for cutting the adhesive tape ( 1 ) into individual ties wherein the cutting means ( 13 ) cut the tape ( 1 ) at positions according to boundary position data received from the detector ( 14 ).

1 . A bag tying machine including 
 a roll of adhesive tape having spaced portions which are non-adhesive, wherein the tape is wholly coated with adhesive and the non-adhesive portions are portions which have been treated to neutralise the adhesive;    a detector for detecting the boundary between the adhesive and non-adhesive portions of the adhesive tape; and,    cutting means for cutting the adhesive tape into individual ties wherein the cutting means cut the tape at positions according to boundary position data received from the detector.    
     
     
         2 . A bag tying machine according to  claim 1 , in which the machine also includes: 
 means to pull the adhesive tape across the path of a gathered together neck of a filled bag; and,    means to apply the cut individual adhesive tape ties around the gathered together neck of a filled bag and to itself to form a completed tie.    
     
     
         3 . A bag tying machine according to  claim 1  or  claim 2 , in which the cutting means cuts the adhesive tape in the middle of a non-adhesive portion so that each tie has a non-adhesive portion at each end of it.  
     
     
         4 . A bag tying machine according to any one of the preceding claims, in which the detector is an optical detector capable of detecting differences in reflection from the adhesive and non-adhesive portions of the tape.  
     
     
         5 . A bag tying machine according to  claim 4 , in which the detector detects differences in colour between the light reflected from the adhesive and non-adhesive portions of the tape.  
     
     
         6 . A bag tying machine according to any one of the preceding claims, in which the machine includes a brake which is actuated to stop movement of the tape before it is cut to form a tie.  
     
     
         7 . A bag tying machine according to  claim 6  when dependent upon  claim 2  or any other claim dependent upon  claim 2 , in which the brake, when actuated, stops the movement of the means to pull the tape across the path of a gathered together bag.  
     
     
         8 . A bag tying machine according to any one of the preceding claims, in which the non-adhesive portions of the tape are parts of the tape on which ink or paint has been applied to its adhesive side.  
     
     
         9 . A bag tying machine according to any one of the preceding claims, in which the tape is spool wound.  
     
     
         10 . A bag tying machine according to any one of the preceding claims, in which the tape is pancake wound.  
     
     
         11 . A bag tying machine substantially as described with reference to the accompanying drawings.