Patent Abstract:
A fully enclosed paperboard carton having a top, a base, a pair of oppositely disposed sides and a pair of oppositely disposed end panels. Each end panel being substantially planar and perpendicular to the base and top. Each side having a lower portion that is substantially planar and perpendicular to the base and an upper portion that is substantially planar and tapers inwardly towards its edge connection with the top.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application Ser. No. 11/250,034, filed Oct. 13, 2005, now U.S. Pat. No. 7,832,621, issued on Nov. 16, 2010, which application claims convention priority from British Patent Application No. 0423162.7, filed Oct. 19, 2004. 
    
    
     INCORPORATION BY REFERENCE 
     U.S. patent application Ser. No. 11/250,034, filed Oct. 13, 2005, and British Patent Application No. 0423162.7, filed Oct. 19, 2004, are hereby incorporated by reference for all purposes as if presented herein in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to fully enclosed cartons made from paperboard for enclosing articles. 
     BACKGROUND 
     Conventional cartons carry bottles, in perhaps a 6×4 array, or in other arrangements in straight-sided rectangular cartons made out of corrugated board or other materials. 
     SUMMARY 
     According to the present invention there is provided a fully enclosed paperboard carton having a top, a base, a pair of oppositely disposed sides and a pair of oppositely disposed end panel arrangements, each end panel arrangement being substantially planar and perpendicular to the base and top and each side having a lower portion which is substantially planar and perpendicular to the base and an upper portion which is substantially planar and tapers inwardly towards its edge connection with the top. 
     Each end panel arrangement can comprise top, base and side end panels each hingedly connected to the respective top, base and sides, all being adhesively secured. 
     In some arrangements, each base end panel can be foldably connected at each side to a gusset panel which in turn is hingedly connected to its adjacent side end panel. Conveniently the fold connection of the gusset panel with the base end panel can be perpendicular to the fold between the base and the base end panel and the fold connection of the gusset panel with the side end panel is 45° relative to the fold connection to the base end panel. 
     Each top end panel can be a primary push through flap to define a handle hole. In some embodiments, at each end of the carton, each of the two side end flaps are positioned behind the top end panel and have a secondary push through flap behind the primary push through flap, all push through flaps being rotatable inwardly through 180° when moved into a carrying position by a user. The primary push through flap at each end can remain hingedly connected to the top end panel along a substantially straight primary fold line and also the secondary can be pushed through flaps at each end remain hingedly connected to the side end panels along substantially straight secondary fold lines adjacent the primary fold line. In some embodiments the primary fold line comprises a pair of folds, spaced vertically by a small distance to define a support panel therebetween. 
     With some arrangements at each end of each side, a corner formation each defines a pair of creases, one crease extending from the apex between the top, side and end panel arrangement to a horizontal crease joining the upper and lower side portions and the other crease extending from the apex between the base, side and end panel arrangement to the join between the upper and lower side portions. 
     Normally lines of weakening can be provided such as in the top and/or sides, to facilitate access to the carton contents. 
     Embodiments of the present invention will now be described in more detail. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The description makes reference to the accompanying drawings in which: 
         FIG. 1  shows a paperboard blank for producing a carton according to the present invention. 
         FIG. 2  is a side view of a carton formed from the blank of  FIG. 1 . 
         FIG. 3  is an end view of the carton shown in  FIG. 2 . 
         FIG. 4  is an end perspective view of the carton shown in  FIG. 2 . 
         FIGS. 5 and 6  are an end perspective view showing the carton in various states of use. 
         FIG. 7  is a close up perspective cross-section of a detail of  FIG. 6 . 
         FIG. 8  is an internal view of the carton shown in  FIG. 6 . 
         FIG. 9  is an end perspective view of the end panels of the  FIG. 2  carton being folded. 
         FIG. 10  is similar to  FIG. 9  but somewhat later in the folding process. 
         FIG. 11  shows a blank, similar to that shown in  FIG. 1 , of an alternate embodiment. 
         FIG. 12  is an end perspective view of the end panels of the  FIG. 11  blank being folded. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1  there is shown a paperboard blank  10  for producing a paperboard carton  11  of the fully enclosed type, as shown in the other figures. The carton  10  could contain a number of bottles, perhaps 24 in a 6×4 array, such as 3×4, 4×3, 4×6, 5×6, 6×5, 3×2, 2×3, 2×6, 6×2, etc., although other sizes and configurations are of course possible. Although shown and described with bottles, the carton  10  could enclose cans or other containers. 
     The blank  10  provides a top  12  which is hingedly connected along a fold  13  to a first upper side portion  14  which in turn is connected to a first lower side portion  15  along a crease  16 . The lower side portion  14  is hingedly connected along a base fold  17  to a base  18  which is hingedly connected along a second base fold  19  to a second lower side portion  20 . The second lower side portion  20  is connected along a crease  21  to a second upper side portion  22  which in turn is hingedly connected to gluing panel  23 . 
     When the pack is being assembled, the base, top and sides can form a sleeve with the gluing panel  23  adhesively secured to the inside of the top  12 . Lines of weakness  24  in the form of perforations or paperboard zips are optionally provided in the top and sides to facilitate access to the contents of the carton  10  after assembly is completed. The precise shape, form and location of the lines of weakness  24  are a matter of design choice. In the embodiment shown there is a small removable portion  25  on which would be printed the bar code or other identifying means for the product, such that, for example, the removable portion  25  could be torn off and handed to the cashier at the point of sale to avoid unnecessary lifting of a potentially heavy carton. 
     Hingedly connected at each end of the base  18  along a fold  26  is a base end panel  27  and hingedly connected at each end of the top  12  along a fold  28  is a top end panel  29 . Each top end panel  29  has a push through flap  30  defined by a cut or an intermittent cut line  31  in the illustrated embodiment. The push through flap  30 , however, remains attached at its upper edge to the top end panel  29  by means of a pair of spaced folds  32  which define therebetween a narrow support panel  33 , the purpose of which will be discussed later. 
     Each base end panel  27  has an upper end portion  34  remote from the fold  26  and a lower end portion  34   a  which is hingedly attached at both sides by means of folds  35  to respective gusset panels  36 . The gusset panels  36  are hingedly connected by means of reverse approximately 45° folds  37  to respective side end panels  38  which in turn are hingedly connected by means of folds  39  to the upper and lower side portions  14 ,  15 . The part of the fold  39  connecting the upper side portions  14 ,  22  to the side end panel  38  is shown in this embodiment as a scored fold line. 
     Each side end panel  38  also has a partial secondary push through flap  40  which is hingedly connected to the side end panel along a fold  41 . Adjacent the secondary push through flap is a hole  42 , the hole  42  and the secondary push through flap  40  being positioned so as to be aligned with the push through flap  30  of the top end panel  29  when the carton  11  is assembled. 
     In each upper side portion  14 , at each end of the carton, a crease  43  extends from the top end corner to the crease  16  a short distance in from the end. Similarly in each lower side portion  15 , there is a crease  44  extending from the base end corner to the crease  16  at the point where the crease  43  meets the crease  16 . 
     The carton  11  can be assembled in a number of ways. In one method, the top, base and sides are folded to form a sleeve by adhesively securing the gluing panel  23  to the inside of the top  12 . This can be done on machine or partially folded/glued blanks  10  can be supplied folded flat and opened up on the machine. The bottles (or other articles) are then inserted through an open end before the end panels are folded and glued. In another method the blanks  10  are folded around the bottles (or other articles) before securing the gluing panel  23  and then folding/gluing the end panels. This latter method makes the blank  10  suitable for running on a conventional machine for producing plain rectangular corrugated board cartons, thus giving the existing machines more flexibility in the types of carton they can produce. 
     The folding of the end panels at each end of the carton  10  is illustrated in  FIGS. 9 and 10 . As the side end panels  38  are folded inwardly across the open end of the sleeve, the base end panel  27  is folded upwardly about the fold  26 . This causes the gusset panels  36  to activate about the fold  35  and the reverse 45° fold  37 . The base end panel  27  is then glued to the side end panels  38 . The top  12  can then be folded down and glued to the side end panels, generally not in the region of or blocking the push through flaps  30 ,  40 . 
     Once folded, the free edges  45  of the gusset panels  36  are elevated from the base  18  of the carton. This forms a tray-like base area such that after the lines of weakening  24  are opened, ice or other substance can be deposited in the carton  10  around the bottles. The paperboard can be treated with a water resistant coating such as “Aquakote” (trade mark). As the ice melts, some cold water is retained in the carton, up to the level of the free edges  45  of the gusset panels  36  thus resisting leakage for a period of time. In this way the pack can be used to chill or keep chilled the contents of the carton and can still be moved due to the wet strength of the treated paperboard. This is in contrast to corrugated board which has a much lower wet strength. 
     The tray aspect of the base is also advantageous when a number of cartons are on pallets ready for distribution. With corrugated cartons, a broken bottle can, through leakage, adversely affect a whole pallet, which can lead to return of the whole pallet. With the present carton, a breakage can be contained as fluid is retained in the tray-like base area for a period of time without leakage. 
     Also during palletizing of cartons, since a likelihood of damage exists, the present carton includes a 4-ply cushion at the lower corner of the end panels. This can reduce the likelihood of damage to the more vulnerable corner bottles and provide improved carton integrity, while maintaining carton appearance. 
     Once the present carton  11  is assembled it has perpendicular end walls and sides that have a tapered upper portion. The top is, therefore, narrower between the sides than the base and this is beneficial for carrying bottles as the tapered sides results in a tighter package around the tops of the bottles. The ends, however, remain perpendicular to the base giving a perception of strength. The presence of the handles in the vertical ends is, however, beneficial. 
     When the carton  10  is to be lifted, the user pushes the push through flaps  30 ,  40  inside and upwardly behind the top end panel as illustrated in  FIGS. 5 to 7 . The vertical nature of the end wall provides sufficient space between the bottle necks and the end wall to accommodate the movement of the flaps  30 ,  40 .  FIG. 7  also shows how the narrow support panel  33  can take up a generally horizontal position accommodating the two plies of the side end panel  38  and its secondary push through flap  40 . The support panel  33  is effective to distribute the weight of the carton better than a simple folded edge. 
     Returning to the perpendicular nature of the end panels, when the carton  11  is lifted by the handles in the end walls, the paperboard only has to contend with shear forces. If the end walls were tapered, there would also be an opening moment, which would make the handle area more prone to ripping. 
     The angled creases  43  and  44  act to facilitate the tapering of the upper side portions  14  when the pack is formed. The creases also give the corners of the carton a softer edge by providing a form of corner panel. This renders the carton less prone to corner damage. 
     Since the blank  110  of  FIG. 11  is substantially identical to that shown in  FIG. 1 , like reference numbers correspond to like parts. In the blank  110 , however, an additional reverse fold  137  in each gusset portion  36 , between the 45° reverse fold  37  and the upright fold  39 . A short cut  111  is provided from the end of the free edge  45  to the upper end of the additional reverse fold  137 . The precise angle of the additional reverse fold  137  depends on a number of parameters, such as size of the end panels, thickness and stiffness of the paperboard etc. 
     It has been found that the additional reverse fold  137  and the cut  111  at each gusset area allows the side end panels  38  to be partially folded in before the base end panel  27  starts to fold up. This helps the side end flaps fold in squarely with minimum stress before pulling up the base end panel  27 . 
     It will be appreciated that some of the features are still a matter of design choice such that variations of the above-described arrangements will still be covered by the following claims.

Technology Classification (CPC): 1