Collapsible packaging sleeve

Abstract

This invention relates to a collapsible packaging sleeve made of a foamed polyolefin material such as polypropylene. The sleeve may be formed from one or more sheets of material joined into a continuous ring, or it may be assembled from separable sleeve parts. The collapsiblity is provided by the removal of material from the sheet(s) to create a recess within the sheet defining a region of reduced thickness. When bent about the region of reduced thickness, the material undergoes the well-known transformation known as “whitening”, enabling it to perform repeated hinging movements.

1 . A collapsible packaging sleeve manufactured from one or more sheets of a foamed polyolefin material.  
     
     
         2 . A packaging sleeve according to    claim 1    in which the polyolefin material is polypropylene.  
     
     
         3 . A packaging sleeve according to    claim 1    in which the sleeve is manfactured from a single sheet of material, the ends of the sheet being bonded together to provide a continuous ring.  
     
     
         4 . A packaging sleeve according to    claim 1    in which the sleeve is assembled from at least two separable sleeve parts, the sleeve including interconnection means by which the sleeve parts may be releasably connected together to form a ring.  
     
     
         5 . A packaging sleeve according to    claim 4    in which each sleeve part is substantially “L”-shaped in its erected condition.  
     
     
         6 . A packaging sleeve according to    claim 5    in which each sleeve part is its erected condition comprises a long side portion, an end portion and a short side portion, the end portion being substantially perpendicular to, and being joined to, both of the side portions.  
     
     
         7 . A packaging sleeve according to    claim 6    in which a short side portion of a first sleeve part and a long side portion of a second sleeve part together define the longer side edge of the erected sleeve, and the end portion of each sleeve part comprises a shorter side edge of the erected sleeve.  
     
     
         8 . A packaging sleeve according to    claim 6    in which the combined length of the short side portion and the end portion of each sleeve part is less than the length of the longer side edge of the erected sleeve.  
     
     
         9 . A packaging sleeve according to claims  6  in which when each sleeve part is collapsed the angle of the hinge between the short side portion and the end portion will be close to zero, whilst the angle of the hinge between the long side portion and the end portion will be close to 180°.  
     
     
         10 . A packaging sleeve according to    claim 6    in which the interconnection means joins the short side portion of a first sleeve part to the long side portion of a second sleeve part.  
     
     
         11 . A packaging sleeve according to    claim 6    in which the interconnection means comprises an extruded component.  
     
     
         12 . A packaging sleeve according to    claim 1    in which the collapsibility is provided by hinges in the material, and in which each hinge is defined by the removal of a linear section of material to provide a recess in the sheet.  
     
     
         13 . A packaging sleeve according to    claim 12    in which the recesses for all of the hinges of the sleeve are formed in the same side of the sheet.  
     
     
         14 . A packaging sleeve according to    claim 12    in which the sheet of material is between 6 mm and 8 mm thick, and in which the hinges are defined by the removal of linear sections of material to provide a recess of a depth sufficient to leave a remaining thickness of between 1 and 2 mm.  
     
     
         15 . A packaging sleeve according to    claim 12    in which the recess has angled sides.  
     
     
         16 . A packaging sleeve according to    claim 14    in which the sides of the recess are angled at between 40° and 50°.  
     
     
         17 . A packaging sleeve according to    claim 12    in which the recess has a substantially flat bottom, the flat bottom having a lateral extent of approximately 1.5-5 mm.  
     
     
         18 . A packaging sleeve according to    claim 12    in which the junction between the sides of the recess and the bottom of the recess is curved.  
     
     
         19 . A packaging sleeve according to    claim 17    in which the junction has a radius of curvature of at least 1 mm.  
     
     
         20 . A packaging sleeve according to    claim 12    in which a 90° corner in the erected sleeve or sleeve part is provided by a single recess.  
     
     
         21 . A packaging sleeve according to    claim 12    in which a 90° corner in the erected sleeve or sleeve part is provided by two parallel recesses close together.  
     
     
         22 . A packaging sleeve according to    claim 21    in which the recesses for each 90° corner are separated by a distance of 10 mm or less.  
     
     
         23 . A packaging sleeve according to    claim 21    in which the recesses are separated by a distance around 0.5 mm greater than the thickness of the sheet.