Packaging Apparatus and Method of Making Packages

Abstract

A packaging apparatus including a cutting device, the cutting device comprising an elongate holder, an elongate knife having an elongate cutting edge, and a heat seal device located on the elongate holder on opposed sides of the knife, the heat seal device comprising a pair of elongate pressure strips projecting outwardly from the elongate holder, each pressure strip extending along a respective side of the knife, wherein each pressure strip comprises an elongate bar mounted for sliding movement in a respective slot in the elongate holder, the sliding movement varying the distance an outer edge of the elongate bar projects from the elongate holder, and a biasing element within the respective slot, the biasing element engaging an inner edge of the elongate bar and arranged to bias the elongate bar outwardly of the slot. A packaging method is also disclosed.

1 . A packaging apparatus including a cutting device, the cutting device comprising an elongate holder, an elongate knife having an elongate cutting edge, and a heat seal device located on the elongate holder on opposed sides of the knife, the heat seal device comprising a pair of elongate pressure strips projecting outwardly from the elongate holder, each pressure strip extending along a respective side of the knife, wherein each pressure strip comprises an elongate bar mounted for sliding movement in a respective slot in the elongate holder, the sliding movement varying the distance an outer edge of the elongate bar projects from the elongate holder, and a biasing element within the respective slot, the biasing element engaging an inner edge of the elongate bar and arranged to bias the elongate bar outwardly of the slot. 
     
     
         2 . A packaging apparatus according to  claim 1  wherein the elongate bar is rigid. 
     
     
         3 . A packaging apparatus according to  claim 1  or  claim 2  wherein the outer edge of the elongate bar has a convex cross-section. 
     
     
         4 . A packaging apparatus according to  claim 3  wherein the convex cross-section is arcuate. 
     
     
         5 . A packaging apparatus according to  claim 4  wherein the arcuate cross-section has a radius from 0.75 to 1.25 mm. 
     
     
         6 . A packaging apparatus according to any foregoing claim wherein the elongate bar has a thickness of from 1.5 to 2.5 mm. 
     
     
         7 . A packaging apparatus according to any foregoing claim wherein the elongate bar is composed of a metal. 
     
     
         8 . A packaging apparatus according to  claim 7  wherein the metal is stainless steel. 
     
     
         9 . A packaging apparatus according to any foregoing claim wherein the elongate bar is captive in the elongate holder. 
     
     
         10 . A packaging apparatus according to  claim 9  wherein the elongate bar has a first coupling element located at each longitudinal end of the elongate bar which couples with a second coupling element located at each longitudinal end of the slot, the first and second coupling elements retaining the elongate bar captive in the elongate holder. 
     
     
         11 . A packaging apparatus according to  claim 10  wherein the first coupling element comprises a male element and the second coupling element comprises a channel extending along the sliding direction of the elongate bar. 
     
     
         12 . A packaging apparatus according to any foregoing claim wherein the biasing element comprises an elongate strip of elastic resilient material. 
     
     
         13 . A packaging apparatus according to  claim 12  wherein the elastic resilient material comprises an elastomeric polymer. 
     
     
         14 . A packaging apparatus according to  claim 12  or  claim 13  wherein the elongate strip of elastic resilient material has an upper surface which mates with the inner edge of the elongate bar. 
     
     
         15 . A packaging apparatus according to any one of  claims 12  to  14  wherein the elongate strip of elastic resilient material has a circular cross-section. 
     
     
         16 . A packaging apparatus according to any foregoing claim wherein the elongate knife is mounted on and projects outwardly from the elongate holder. 
     
     
         17 . A packaging apparatus according to any foregoing claim wherein the holder is mounted on a mounting support adapted to rotate about a rotational axis, the knife is planar, the elongate cutting edge is parallel to the plane of the knife and the plane of the knife is inclined to the rotational axis. 
     
     
         18 . A packaging apparatus according to  claim 17  wherein the cutting edge extends along a centre of the knife. 
     
     
         19 . A packaging apparatus according to  claim 18  wherein the knife has a thickness of from 1 to 3 mm. 
     
     
         20 . A packaging apparatus according to any foregoing claim further comprising an anvil mounted in opposition to the elongate holder, so that the elongate holder and the anvil comprise opposed jaws of a jaw device, the anvil having a reaction surface for the cutting action of the knife and for the pressure strips. 
     
     
         21 . A packaging apparatus according to  claim 20  wherein the holder is mounted on a mounting support adapted to rotate about a rotational axis, the elongate cutting edge is parallel to the plane of the knife and the plane of the knife is inclined to the rotational axis and the knife and anvil are mutually arranged so that as the knife rotates by rotation of the elongate holder, the cutting edge of the knife progressively contacts the reaction surface with a contact point therebetween moving longitudinally along the cutting edge. 
     
     
         22 . A packaging apparatus according to  claim 20  or  claim 21  wherein the anvil comprises a heater for heating the reaction surface. 
     
     
         23 . A packaging apparatus according to any foregoing claim adapted for forming pillow packs of film material. 
     
     
         24 . A method of making packages, the method comprising the steps of:
 a. providing a flattened tube of packaging film;   b. providing a cutting device mounted in opposition to an anvil so that the cutting device and the anvil comprise opposed jaws of a jaw device, the cutting device having an elongate knife with an elongate cutting edge, a pair of elongate pressure strips projecting outwardly from an elongate holder, each pressure strip extending along a respective side of the knife, wherein each pressure strip comprises an elongate bar mounted for sliding movement in a respective slot in the elongate holder, the sliding movement varying the distance an outer edge of the elongate bar projects from the elongate holder, and a respective biasing element within the slot, the biasing element engaging an inner edge of the elongate bar and arranged to bias the elongate bar outwardly of the slot, and the anvil having a reaction surface for the cutting action of the knife and for the pressure strips, at least the reaction surface for the pressure strips being heated;   c. locating a portion of the flattened tube between the cutting device and the anvil;   d. relatively moving the cutting device and the anvil together;   e. cutting through the portion of the flattened tube between the cutting device and the reaction surface of the anvil by the cutting action of the knife; and   f. pressing the pressure strips against the heated reaction surface thereby simultaneously heat sealing together opposed sides of the flattened tube to form an elongate transverse hermetic seal in the vicinity of each cut end of the flattened tube, during the pressing action each elongate bar sliding rearwardly in the respective slot against the bias of the biasing element within the slot.   
     
     
         25 . A method according to  claim 24  wherein the biasing element comprises an elongate strip of elastic resilient material. 
     
     
         26 . A method according to  claim 25  wherein the elastic resilient material comprises an elastomeric polymer. 
     
     
         27 . A method according to any one of  claims 24  to  26  wherein the elongate bar is rigid. 
     
     
         28 . A method according to any one of  claims 24  to  27  wherein the outer edge of the elongate bar has a convex cross-section. 
     
     
         29 . A method according to  claim 28  wherein the convex cross-section is arcuate. 
     
     
         30 . A method according to  claim 29  wherein the arcuate cross-section has a radius from 0.75 to 1.5 mm. 
     
     
         31 . A method any one of  claims 24  to  30  wherein the elongate bar has a thickness of from 1.5 to 2.5 mm. 
     
     
         32 . A method according to any one of  claims 24  to  31  wherein the cut edge of each package is 0.5 to 1.5 mm from the hermetic seal. 
     
     
         33 . A method according to  claim 32  wherein the cut edge of each package is about 1 mm from the hermetic seal. 
     
     
         34 . A method according to any one of  claims 24  to  33  wherein the hermetic seal has a width of from 1 to 4 mm. 
     
     
         35 . A method according to  claim 34  wherein the hermetic seal has a width of from 1 to 2 mm. 
     
     
         36 . A method according to any one of  claims 24  to  35  wherein the packages are pillow packs of film material. 
     
     
         37 . A method according to  claim 36  wherein the packages contain snack food.