Abstract:
A carton and blank for forming a carton for accommodating a pizza or the like, comprising a top, a base panel, a pair of oppositely disposed side panels interconnecting said top and said base to provide a flat tubular structure and an end closure arrangement to close opposite ends of the carton including end flaps adjoining said top and said base panel and a corner closure structure at each corner of the carton including an ellipsoidal panel adjoining at least one of said top panel and said base panel.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This is a divisional application of U.S. patent application Ser. No. 09/355,702 filed Sep. 27, 1999, now abandoned.  
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Technical Field of the Invention  
           [0003]    The invention relates to sealable cartons, and more particularly to sealable cartons having diagonal corner blanks for forming such cartons.  
           [0004]    2. Background of the Invention  
           [0005]    A tray-like shallow carton having angled (or diagonal) corners is a convenient means for packaging many items, particularly generally flat food items such as pizza. The angled corners provide a geometric structure that strengthens the carton by increasing its load bearing capacity. The contents of such a carton are protected from damage that might occur from loads typically placed upon the carton. An example of a typical load is the weight produced when multiple cartons are stacked one upon another for shipping and/or storage. Often, although the angled corner structure is beneficial the resulting geometric configuration results in a substantially open or openable corner structure through which contaminants may enter. What is needed is a diagonally cornered carton whose angled corners inhibit the entrance of contaminants into the carton.  
           [0006]    Blanks for forming cartons are made from paperboard or other suitable material. It is highly desirable to minimise the amount of excess carton forming material when such blanks are made. Preferably the blank should be manufactured with a minimum of excess carton forming material.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    According to one aspect of the invention, there is a carton for accommodating a pizza or the like, comprising a top, a base panel, a pair of oppositely disposed side panels interconnecting said top and said base to provide a flat tubular structure and an end closure arrangement to close opposite ends of the carton including at each corner of the carton a corner panel hinged to adjacent side wall and top and base and having means for attachment to further end flaps hinged to said top and bottom panels.  
           [0008]    According to one optional feature, said corner panel may be displaced inwardly of said end flaps.  
           [0009]    According to another optional feature, the corner panel may comprise a central panel adapted to provide a bevelled corner to said carton and a gusset panel hinged to said central panel and said top and a second gusset panel hinged to said central panel and said base wherein said gusset panels extend outwardly from said central panel and adapted to provide a sealed corner of said carton.  
           [0010]    According to another aspect of the invention, there is a blank for forming a flat tubular carton comprising a top panel, a base panel, a pair of oppositely disposed side and end walls hingeably connected to said top panel and/or said base panel and an end closure arrangement including a corner panel hingeably connected to a side wall and a gusset panel connected to said corner panel and one of said top panel and/or said base panel.  
           [0011]    According to one optional feature of this aspect of the invention said corner panel may be hingeably connected to said top panel and said base panel.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0012]    Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:  
         [0013]    [0013]FIG. 1 is a plan view of a blank for forming a sealable carton according to a preferred embodiment of the invention;  
         [0014]    [0014]FIG. 2 is an isometric illustration of a carton fully closed and sealed;  
         [0015]    [0015]FIG. 3 is a plan view of a blank for forming a sealable container according to a second preferred embodiment of the invention;  
         [0016]    [0016]FIG. 4 is an isometric illustration of a carton erected from a blank of FIG. 3 fully closed and sealed;  
         [0017]    [0017]FIG. 5 is a plan view of a blank for forming a sealable carton according to a third preferred embodiment of the invention;  
         [0018]    [0018]FIG. 6 is an isometric illustration of a carton erected from a blank of FIG. 5 fully closed and sealed;  
         [0019]    [0019]FIG. 7 is a plan view of a blank for forming a sealable carton according to a fourth embodiment of the invention;  
         [0020]    [0020]FIG. 8 is an isometric illustration of a carton erected from a blank of FIG. 7 fully closed and sealed;  
         [0021]    [0021]FIG. 9 is a plan view of a blank for forming a sealable carton according to a fifth embodiment of the invention; and  
         [0022]    [0022]FIG. 10 is an isometric illustration of a carton erected from a blank of FIG. 9 fully closed and sealed.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]    Referring first to FIG. 1, there is illustrated a blank  10  for forming a sealable carton according to a preferred embodiment of the invention. The carton blank is made from paperboard or other similar foldable sheet material. The blank comprises a first side panel  12 , a top panel  14 , a second side panel  16 , a base panel  18 , an outer side panel  20  hingeably connected one to the next along fold lines  22 , 24 , 26 , 28  respectively.  
         [0024]    An end flap  30  is hingeably connected to a side edge of top panel  14  along fold line  32 . A second end flap  34  is hingeably connected to the opposing side edge of top panel  14  along fold line  36 . Likewise, an end flap  38  is hingeably connected to a side edge of base panel  18  along fold line  40 . A second end flap  42  is hingeably connected to the opposing side edge of base panel  18  along fold line  44 .  
         [0025]    Top panel  14  and base panel  18  include a pair of fold lines  46 , 48 ;  50 , 52  extending longitudinally between side panel  12 , side panel  16  and side panel  16 , side panel  20  respectively.  
         [0026]    A corner panel  54  is hingeably connected to a side edge of side panel  12  along fold line  56 . Corner panel  54 , is hingeably connected to gusset panel  58  along lateral fold line  60 , which in this embodiment is an extension of fold line  22 . Gusset panel  58  is substantially arcuate in shape and is hingeably connected to top panel  14  along fold line  62 . Fold line  62  extends outwardly from the intersection of fold lines  56  and  60 , to the intersection of the free edges of top panel  14  and gusset panel  58 .  
         [0027]    Similarly, a second corner panel  64  is hingeably connected to the opposing side edge of side panel  12  along fold line  66 . A second gusset panel  68  hingeably connects corner panel  64  and top panel  14 . Corner panel  64  and gusset panel  68  are in symmetrically opposite positions to corner panel  54  and gusset panel  58  and are of similar construction and not therefore more specifically described.  
         [0028]    A corner panel  70  is hingeably connected to a side edge of outer side panel  20  along fold line  72 . Corner panel  70 , is hingeably connected to gusset panel  74  along lateral fold line  76 , which in this embodiment is an extension of fold line  28 . Gusset panel  74  is substantially arcuate in shape, being hingeably connected to base panel  18  along fold line  78 . Fold line  78  extends outwardly from the intersection of fold lines  28  and  72 , to the intersection of the free edges of base panel  18  and gusset panel  74 .  
         [0029]    Similarly, a second corner panel  88  is hingeably connected to the opposing side edge of side panel  20  along fold line  86 . A second gusset panel  84  hingeably connects corner panel  88  and base panel  18 . Corner panel  88  and gusset panel  86  are in symmetrically opposite positions to corner panel  70  and gusset panel  74  and are of similar construction and not therefore more specifically described.  
         [0030]    As shown in FIG. 1, a pair of corner panels  92 , 108  is struck from opposing side edges of the side panel  16 . In particular, corner panel  92  is hingeably connected to a side edge of side panel  16  along fold line  94 . Fold line  44  extends longitudinally between fold line  46  and fold line  50 . A glue flap  96  is hingeably connected along the opposing side edge of corner panel  92  along fold line  98 . Gusset panels  100  and  102  are hingeably connected to opposing upper and lower edges of corner panel  92  by fold lines  101 , 103  respectively. Fold lines  101  and  103  are lateral extensions of fold lines  24  and  26  respectively.  
         [0031]    Gusset panel  100  is substantially arcuate in shape and is hingeably connected to top panel  14  along fold line  104 . Fold line  104  extends outwardly from the intersection of fold lines  94  and  24 , to the intersection of the free edges of top panel  14  and gusset panel  100 . Likewise, gusset panel  102  is substantially arcuate in structure and hingeably connected to base panel  18  along fold line  106 . Fold line  106  extends outwardly from the intersection of fold lines  94  and  26 , to the intersection of the free edges of base panel  18  and gusset panel  102 .  
         [0032]    Likewise, the opposing side edge of side panel  16  is hingeably connected to a corner panel  108  which also comprises a pair of gusset panels  110  and  112  and a glue flap  114 . The aforementioned panels are in symmetrically opposite positions to corner panel  92 , gusset panels  100 , 102  and glue flap  96  and are of similar construction and not therefore more specifically described.  
         [0033]    Turning to the construction of the carrier, illustrated in FIG. 2, side panel  12  is folded about fold line  22  and into substantially perpendicular relationship with top panel  14 , thereby folding corner panels  54  and  64  into substantially perpendicular relationship with gusset panels  58  and  68  respectively. Top panel  14  and base panel  18  are folded into a spaced face to face relationship. More specifically, side panel  16  is folded into substantially perpendicular relationship with top panel  14  and base panel  18  about fold lines  24  and  26  respectively such that top panel  14  and base panel  18  are aligned but separated by side panels  12  and  16 .  
         [0034]    Central panels  92  and  108  are in a perpendicular relationship with respective pairs of gusset panels  100 , 102  and  110 , 112 . Outer side panel  20  is folded about fold line  28  into substantially perpendicular relationship with base panel  18  and into a face to face relationship with side panel  12 . It will be appreciated by those skilled in the art that panels  12  and  20  can be interchanged so that, for example panel  12  could form the outer side panel, according to particular manufacturing requirements.  
         [0035]    Side panels  12  and  20  and, preferably, corner panels  54 , 70  and  64 , 88  are secured together by glue or other means known in the art thereby forming a flat tubular structure.  
         [0036]    The carrier is in a part erected condition and is able to receive flat food items, for example a pizza, from either end of the carton. The pizza is inserted from one side and to avoid the pizza being caught on either the base or top panel, part of the top panel  14  and bottom panel  18  are temporarily folded out of alignment with the rest of aforesaid panels about fold lines  46  and  50  or, depending on the point of entry of the pizza, fold lines  48  and  52 . The temporary folds  46 , 48 ;  50 , 52  also provide flexibility to the top and base panels when constructing the corner structures.  
         [0037]    Once the flat food item has been placed within the carton, the corner structures are then formed. Corner panel  92 , is folded in an inward direction about fold line  94  such that gusset panels  100  and  102  are also folded out of alignment. More particularly, gusset panel  100  is folded about fold line  104  and into a face to face relationship with top panel  14  such that a substantially perpendicular relationship is formed with corner panel  92  about fold line  101 . Likewise gusset panel  102  is folded about fold line  106  and into a substantially face to face relationship with base panel  18  such that a substantially perpendicular relationship is formed with corner panel  92  about fold line  103 .  
         [0038]    Likewise, corner panels  70 , 54  are folded inwardly such that gusset panels  74  and  58  are folded in substantially the same way as gusset panels  100  and  102  described above. Thereafter glue flaps  80 , 96  are folded into an angular relationship with corner panels  92  and  70  respectively and end flaps  30  and  38  are folded about fold lines  32  and  40  and into a perpendicular relationship with top panel  14  and base panel  18  respectively. End flaps  30  and  38  are connected together by glue or other means known in the art and connected to glue flaps  80  and  96  by glue or other means known in the art. An end structure E is thereby formed, as illustrated in FIG. 2.  
         [0039]    The opposing end structure incorporating corner panels  88 , 64  and  108  and end flaps  34 , 42  is constructed in a similar way to corner panels  54 , 70  and  92  and end flaps  30 , 38  and are therefore not described in any greater detail. Thus, the carton is in its completed form illustrated in FIG. 2.  
         [0040]    Turning to the second embodiment illustrated in FIGS. 3 and 4, the blank is substantially similar to the embodiment illustrated in FIGS. 1 and 2 with side panels  150 , 154 , 158 , top and base panels  152 , 156  and end flaps and therefore only the differences are described in any greater detail. In this embodiment, the corner structures comprise a corner panel  160  hingeably connected to side panel  154  about fold line  162 . A gusset panel  164  is hingeably connected to the upper edge of corner panel  160  along fold line  166 . Gusset panel  164  is connected to top panel  152  by means of a connecting portion  168  which is hingeably connected to gusset panel  164  along fold line  170  and is hingeably connected to top panel  152  along fold line  172 . Gusset panel  164  is positioned adjacent to top panel  152  but separated therefrom by cut line  174  which extends from the inner edge of fold line  172  to the intersection of fold lines  162  and  166 .  
         [0041]    Likewise, a gusset panel  176  is hingeably connected to the lower edge of corner panel  160  along fold line  178 . Gusset panel  176  is connected to base panel  156  by means of a connecting portion  180  which is hingeably connected to gusset panel  176  along fold line  182  and is hingeably connected to base panel  156  along fold line  184 . Gusset panel  176  is positioned adjacent to base panel  156  but separated therefrom by cut line  186  which extends from the inner edge of fold line  184  to the intersection of fold lines  162  and  178 .  
         [0042]    The other corner structures are formed in substantially the same way as corner panel  160  and gusset panels  164 , 176  and are therefore not described in any greater detail.  
         [0043]    The construction of the corner structure is carried out after the carton is partly erected into a flat tubular structure as described earlier. The corner structure is formed by folding corner panel  160  inwardly towards the adjacent end flaps by folding corner portions  168  and  180  about fold lines  172 , 170  and  184 , 182  respectively such that corner portion  168  is in a face to face relationship with top panel  152  and corner portion  180  is in a face to face relationship with base panel  156 . Gusset panels  164  and  176  are folded out of alignment and into substantially perpendicular relationship with corner panel  160  such that corner portion  168  forms a face to face relationship with gusset panel  164  and corner portion  180  forms a face to face relationship with gusset panel  176 . Preferably, gusset panel  164  is secured to top panel  152  by glue or other means known in the art. Likewise, gusset panel  176  is preferably secured to base panel  156  by glue or other means known in the art. The other corner structures are constructed in the same way, as understood by those skilled in the art, and the end flaps secure together to form the carton in its completed sealed form as illustrated in FIG. 4.  
         [0044]    Turning to the third embodiment illustrated in FIGS. 5 and 6, the blank is substantially similar to the embodiment illustrated in FIGS. 1 and 2 comprises side panels, top and base panels and end flaps and therefore only the differences are described in any detail. In this embodiment an octagonal structure is formed. A first corner structure comprises a pair of corner panels  210 , 202  hingeably connected to respective ones of top panel and base panel. Corner panel  202  is positioned adjacent to its top panel but is separated by an ellipsoidal intermediate panel  204  hingeably connected to a top panel along fold line  206  and to corner panel along fold line  208 . A glue flap  210  is hingeably connected to the adjacent side panel. Other corner structures are identical to the corner structure described above and are therefore not described in any greater detail.  
         [0045]    The construction of the corner structure is carried out after the carton is partly erected into a flat tubular structure as described earlier. The corner structure is formed by folding corner panel  200  into a substantially perpendicular relationship with base panel and by folding corner panel  202  about fold line  208  and intermediate panel about fold line  206  with top panel such that a substantially perpendicular relationship is formed between corner panel  202  and the top panel. The corner panels  200  and  202  are placed into an overlapping relationship and connected together by glue or other means known in the art. The corner structure is connected to the side panel by glue flap  210 . The other corner structures are constructed in the same way, as understood by those skilled in the art so that the carton is in its completed sealed form, as illustrated in FIG. 6.  
         [0046]    Turning to the construction of the fourth embodiment illustrated in FIGS. 7 and 8 and the fifth embodiment illustrated in FIGS. 9 and 10, the blanks are substantially similar to the embodiments illustrated above comprising side walls, top and base panels and end flaps and therefore only the differences in each embodiment are described in any great detail.  
         [0047]    In the fourth embodiment shown in FIG. 7, a corner panel  300  is hingeably connected to base panel along fold line  302 . A pair of gusset panels  304 , 306  is hingeably connected along a side edge of corner panel  300  and to an end flap of the base panel. Likewise, a pair of gusset panels  308  and  310  are hingeably connected to the opposing side edge of corner panel  300  and to a side edge of side panel interconnecting the top panel and base panel.  
         [0048]    In the fifth embodiment shown in FIG. 9, a corner panel  400  is hingeably connected to the top panel along fold line  402 . A gusset panel  404  is hingeably connected to an end flap being connected to the top panel. Gusset panel  404  is substantially triangular in shape. A second gusset panel  406  is hingeably connected to a side panel interconnecting the top and base panels. The shape of the gusset panels can be altered to provide overlapping arrangement depending upon manufacturing requirements. The corner panel  406  is hingeably connected to gusset panel  404  by connecting portion  408 . Likewise, corner panel  400  is hingeably connected to gusset panel  406  by connected portion  410 . The other corner structures of each embodiment are formed in substantially the same way and are not therefore described in any greater detail.  
         [0049]    The construction of the corner structure of the fourth and fifth embodiments is carried out after the carton is partly erected into a flat tubular structure as described earlier.  
         [0050]    The corner structure in the fourth embodiment illustrated in FIG. 7 and  8 , is formed by folding the pair of gusset panels  304 , 306  into a face to face relationship with each other and the pair of gusset panels  308  and  310  into face to face relationship such that the upper edge of corner panel  300  comes into contact with the free edge  312  of the top panel and are connected together by means of a glue flap  314 . It will be appreciated by those skilled in the art that the end flaps from the top panel and base panel respectively are thus placed in an overlapping relationship and can be connected together. Optionally, the gusset panels can be secured to the side wall or end flap to provide a sealed carrier, as illustrated in FIG. 8.  
         [0051]    Turning to the construction of the corner structure of the fifth embodiment the connecting portion  408  is folded into an overlapping face to face relationship with corner panel  400  and gusset panel  404 . Likewise, connecting portion  410  is folded into an overlapping face to face relationship with corner panel  400  and gusset panel  406 . Preferably, the corner panel  400  and gusset panels  404 , 406  are secured together by glue or other means known in the art. Gusset panel  404  is connected to base panel by means of glue flap  412 . The other corner structures are constructed in the same way and the end flaps secured together by glue or other means known in the art to provide a sealed carrier as illustrated in FIG. 10.  
         [0052]    Of course, the construction of the corner structures of any of the embodiments can be carried out at substantially the same time or, if preferred, one end can be constructed prior to inserting the pizza. In addition, the shape of the corner panels and gusset panels can be adapted according to the desired final shape of carton. Preferably the gusset panels are secured in a face-to-face relationship with top panel, base panel or, as the case may be, side panel to provide a fully sealed unit. The corner panels are intended to be load bearing so that cartons can be stacked. By positioning the corner panels closer to the notional centre point C of the carton, shown in FIG. 2, a stronger carton, capable of supporting a greater load, can be provided.  
         [0053]    The present invention and its preferred embodiments relate to a flat tubular structure which is shaped to provide a satisfactory rigidity to hold items such as a pizza securely but with a degree of flexibility so that the load transferred from stacked cartons can be better absorbed by the carrier. The shape of the blank minimises the amount of paperboard required in each embodiment. The items can be applied to the carrier by hand or by automatic machinery. It is anticipated that the invention can be applied to a variety of carriers and not limited to those of the flat tubular sort.