Abstract:
A collapsible container made from sheet material, comprising a cover portion and a base portion; the cover portion and base portion each being pivotally connected at respective spaced fold lines to a rear wall each, wherein each of the cover portion and base portion comprises a main panel having, at its edge remote from the rear wall portion, a front wall and, at its opposite side edges, side walls wherein the side and front walls portions of the cover portion interfit with one another to retain them in position extending generally perpendicular to the panel of the cover portion and the side and front walls of the base portion are able, to lie within inwardly facing surfaces of the side and front walls of the cover portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 USC 119(a)-(d) to United Kingdom Patent Application No. 1210917.9 filed Jun. 20, 2012, which is incorporated by reference in its entirety herein. 
       BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    This invention relates to a container, made out of a sheet material such as corrugated cardboard. 
         [0003]    The invention has been devised for use a food container, particularly a so-called pizza box, commonly used by fast-food establishments for containing ready to eat pizza for consumption off the premises. Although it will be understood that the invention may be applicable to containers intended for purposes other than receiving pizzas, the term “pizza box” will be used herein for convenience in describing the invention. Conventional pizza boxes, whose configuration has changed little for many years, are made out of a suitable paper-based board material in order to be bio-degradable, and are supplied to pizza vendors in the form of flat pieces of such material, cut to the required shape and pre-formed with lines along which the material is readily foldable. When the container is required to be used, it is readily erected by folding along the pre-formed lines to create a box which is usually square or rectangular in plan view of dimensions suitable to accommodate a respective diameter of pizza, and of a height sufficient to accommodate the thickness of the pizza. The box, as erected, has a base portion the form of a tray, with front, rear and side walls upstanding from a base panel, and a lid or cover which opens pivotally to give access to the interior of the box. A pizza can be placed downwardly into the erected base portion; if one were to be placed on the base panel with the base portion of the box not erected it would impede the erection process of the base portion. 
         [0004]    Pizza boxes are intended for a single use only, after which they are discarded as refuse or for recycling. Clearly, it is advantageous if the amount of cardboard used in each box is minimised: even a small saving in cardboard usage becomes significant when multiplied by the number of boxes used throughout the world. Other desirable characteristics of pizza boxes are that they should be easy to erect from the flat condition and to collapse for disposal after use, while being robust and resistant to accidental collapse when erected so that a pizza contained in the box is adequately protected. 
         [0005]    It is broadly the object of the present invention to address these desirable aspects of pizza box construction and disadvantages of conventional pizza boxes. 
       SUMMARY OF THE INVENTION 
       [0006]    According to one aspect of the invention, we provide a collapsible container made from sheet material, comprising a cover portion and a base portion; the cover portion and base portion each being pivotally connected at respective spaced fold lines to a rear wall portion, wherein each of the cover portion and base portion comprises a main panel having, at its edge remote from the rear wall portion, a front wall and, at its opposite side edges, side walls; wherein the side and front walls portions of the cover portion interfit with one another to retain them in position extending generally perpendicular to the panel of the cover portion; and the side and front walls of the base portion are able to lie within inwardly facing surfaces of the side and front walls of the cover portion. 
         [0007]    In a container, particularly a pizza box, in accordance with the invention, the above-described construction, with the cover portion having its side and front walls interfitting so that they are retained in the orientation generally perpendicular to the panel of the cover portion, means that the base portion of the container can, after the cover portion of the box has been erected, remain flat so that a pizza can be placed thereon and, if required, cut into portions. A pizza can be slid sideways, if desired, onto the base portion of the box rather than having to be placed downwardly into the base portion of a conventional box. If desired, the cover portion of the box could be erected after a pizza has been placed on the base portion, since such erection is not impeded by the presence of the pizza. Thereafter the side and front walls of the base portion can be folded upwardly from the panel of the base portion to extend generally perpendicular to the panel of the base portion, and be retained in that position by closing of the cover portion so that they are constrained by lying within the side and front walls of the cover portion. 
         [0008]    In view of the above, it will be noted that pizza boxes awaiting use can be stored flat, i.e. need not be pre-erected before they are used. This is convenient in saving time and space in a pizza vendor&#39;s premises. 
         [0009]    The side walls of the cover portion may be provided, at their free end adjacent the front wall of the cover portion, with tabs which engage the front wall, preferably by being folded to extend generally at right angles to the side walls and which are constrained between surfaces of respective parts of the front wall which have been folded to overlie one another. 
         [0010]    The respective parts of the front wall may be retained in their overlying position by formations on one part of the front wall, engaging in receiving formations where the other part of the front wall meets the panel of the cover portion. 
         [0011]    Prior to the folding of the front wall so that its one portion overlies the other, the dimension of the front wall may be substantially that of the height of the side walls of the cover portion (and hence that of the side and front walls of the base portion). 
         [0012]    At least one of the cover and base portions may have at least its panel provided with a surface relief extending between opposite portions of the panel to facilitate folding of the panel along such relief, to reduce the size of the container for disposal after use. 
         [0013]    There may be first and second surface reliefs extending along respective axes running between opposed portions of the panel and through a central region of the panel, the axes extending generally perpendicular to one another. 
         [0014]    Such relief or reliefs may extend from the panel into the connected wall portions of the container at the edges thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    These and other features of the invention will now be described by way of example with reference to the accompanying drawings. 
           [0016]      FIG. 1  is a plan view of a blank for erection into a pizza box in accordance with the invention. 
           [0017]      FIGS. 2 to 8  are perspective views showing successive stages of erection of the blank of  FIG. 1  into a pizza box, and the subsequent collapse and folding of the pizza box for disposal. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    Referring firstly to  FIG. 1  of the drawings, the blank comprises a piece of corrugated cardboard which overall is generally of rectangular shape. It is provided with a number of cut lines (where the corrugated cardboard is completely severed) and fold lines (where the corrugated cardboard is alternately creased and cut through, e.g. 10 mm crease followed by 10 mm cut, successively, along the length of the line). There are also some fold lines where the board is creased slightly to guide and facilitate folding, but somewhat less easily than where the crease/cut fold lines are provided. The corrugated cardboard is of the type having first and second parallel surface layers separated by a corrugated layer or flute, and in  FIG. 1  of the drawing, the preferred longitudinal direction of the corrugations of the flute is as indicated alongside the drawing. The flute may be of the “E” flute type, providing the corrugated cardboard with an overall thickness of approximately 2 mm. 
         [0019]    The blank, illustrated generally at  10  comprises two main portions  12 ,  14  which respectively form a cover portion of the box and a base portion of the box. They are connected to one another, along fold lines  16 ,  18  which are parallel to one another, by a portion  20  which forms an upstanding rear wall of the erected box, the two fold lines  16 ,  18  providing for generally pivotal movement of the cover portion of the box relative to the base portion about two parallel axes afforded by the fold lines  16 ,  18 . This enables the main panels (described hereafter) of the cover portion and base portion of the erected box to lie in spaced parallel relation to one another. 
         [0020]    The cover portion  12  of the blank comprises a main substantially rectangular panel  24  along whose opposite sides are provided, in mirror image of one another, flaps  22  delineated by respective fold lines  26 . These form side walls of the cover portion of the erected box. At the ends of the flaps  22  remote from the fold line  16 , there are respective tabs  28  of which each comprises a transition portion  28   a  leading into an engagement portion  28   b  which is of slightly less than half the lateral dimension of the main part of the flap  22 . 
         [0021]    Between the tabs  28 , the end of the panel  24  remote from the fold line  16  is provided with a flap indicated generally at  30  connected to the panel  24  along a fold line  32  which is interrupted by two completely cut portions  34  which are slightly off-set towards the fold line  16 . The flap itself, which forms the front wall of the erected box, comprises two parts  36 ,  38  of which the former has its ends tapered, leading into the part  38  which hence has its ends spaced from the tabs  28  in the flat blank. The parts  36 ,  38  are connected to one another by two closely spaced parallel fold lines  40 . The free edge of the part  38  has two projecting elongate tabs  42  spaced along it, in alignment with the off-set cut line portions  34 . 
         [0022]    The base portion  14  of the blank has a main panel  44  of the same dimensions as the main panel  24  of the cover portion  12 . Along opposite sides of the panel  44  there are respective flaps  46  delineated by fold lines  48 . Connected at the ends of the flaps  46  which lie nearest the flaps  22  there are respective tabs  50  which are connected to the flaps  46  along respective crease lines  52  and are separated from the flaps  22  and wall portion  20  by cut lines. The outer edges of the tabs  50 , facing oppositely away from one another in the flat blank, each have two converging inwardly extending cut lines  54 . 
         [0023]    The edge of panel  44  remote from the fold line  18  is provided with a flap  56  delineated by fold line  58 . At the opposite ends of the flap  56 , there are respective tabs  60  connected to the flap by crease lines  62  and completely separated by cut lines from the flaps  46 . 
         [0024]    The above described features of the blank enable it to be erected for use as a pizza box, in the manner described hereafter. The box is also provided with features, as follows, which facilitate its folding to a significantly smaller size to facilitate its disposal after use. It will be appreciated that a large pizza, e.g. of 300 mm diameter, necessitates a box whose dimensions when erected are greater than can readily be accommodated in a typical waste bin likely to be provided in the home. 
         [0025]    Each of the panels  24 ,  44  has a crease line  66 ,  68  respectively extending transversely across it, these crease lines extending into the respective side flaps  22 ,  46 . Two parallel fold lines  70  extend from the crease line  66  towards the wall portion  20 , followed by two parallel, more closely-spaced, fold lines  72  extending across the wall portion  20  towards the crease line  68 . Beyond the crease line  68  and generally in line with the fold lines  70 ,  72  a crease line  74  extends into the flap  56 . 
         [0026]    Further features of the blank for the pizza box are that the fold line  16  has a central portion  76  which is cut right through and off-set from the fold line  16 . The purpose of this is to provide, when the box is erected as described hereafter, a vent for the interior of the box since it will be appreciated that when the panel  24  extends at right angles to the wall portion  20  the shallow tab formed by the cut portion  76  will extend in alignment with the panel  54  and open space between it and the wall portion  20 . The panel  44  is provided with a number of radial markings  78  to give a guide for cutting of a pizza into sector-shaped portions. Finally, the panel  24  is provided with cut and fold line formations  80  which provide for the holding of portions of sauces, etc. 
         [0027]    Referring now to  FIGS. 2 to 4  of the drawings, these show successive stages of erection of the blank into a pizza box.  FIG. 2  shows the blank ready for erection, with its peripheral tabs and flaps slightly displaced from the general plane of the remainder of the blank. The first stage of erection is that the cover is constructed, by folding the flaps  22  upwardly from the opposite edges of the panel  24  until they lie approximately at right angles to the plane of the panel  24 , and the tabs  28  at the ends of the flaps  22  are folded towards one another so that they are in alignment with the fold line  32 . The portion  30  is then folded upwardly about the fold line  32  so that the parts  28   b  of the tabs  28  are in face to face relationship with the part  36  of the portion  30 . Then, the part  38  is folded over, about the fold lines  40 , so that it lies in face to face engagement with the part  36 , with the parts  28   b  of the tabs trapped between the opposed surfaces of the parts  36 ,  38  at the ends of the portion  30 . In this condition, the tabs  42  engage in slots formed by the offset cut parts  34  interrupting the fold line  32 , when the part  36  is folded upwardly relative to the panel  24 . Hence, the part  30  forms a double-thickness end wall of the cover portion of the box, while the flaps  22  form side walls of the cover portion of the box, the end wall of the cover portion being of half the height of the side walls. 
         [0028]    After erection of the cover portion of the box, a pizza to be put in the box may then be placed on the upper surface of the base portion panel  44  of the box. The pizza may be cut in situ on the box, such cutting being guided, if desired, by the markings  78  on the base portion of the box. This may be done before the flaps which form the side and end walls of the base of the box are folded upwardly relative to the panel  44 , so that upwardly extending side and end walls of the base do not impede the cutting operation of the pizza, significantly easing this operation compared with previously-known pizza boxes. 
         [0029]    Subsequently, ( FIG. 4 ) the flaps  46  and  56  may be folded upwardly from the panel  24 , the tabs  60  at the ends of flap  56  lying within and face to face with the adjacent end portions of the flaps  46  forming the side walls of the base. The box may be closed by pivoting the cover portion of the box about the fold lines  16 ,  18  so that its cover panel  24  lies above the base panel  44 , spaced therefrom by the height of the side walls of the base determined by the flaps  46  and  56 . The flaps  22  forming the side walls of the cover, and the end wall of the cover formed by portion  30 , lie to the exterior of the respective side and end walls of the base. The closed box is shown in  FIG. 5 . 
         [0030]    After use of the pizza box, the box may be reduced to a smaller and more convenient size for disposal, firstly by opening out all the parts of the box so that the form of a generally flat piece of cardboard is again assumed (although it will be appreciated that the folding of the original blank to the form of the box will mean that the cardboard will not naturally assume a completely flat configuration.  FIG. 6  shows that the cover panel  24  has been folded about the crease line  66 , and  FIG. 7  shows that subsequently the base panel  44  has been folded about the crease line  68 . The cover portion and base portion of the box can now be folded towards one another as shown by the arrows on  FIG. 7 , about the fold line  18 , so that the original blank is reduced to approximately one quarter of its original length, comprising four thicknesses of the cardboard material of the blank. The fold lines  70 ,  72 , and  74  overlie one another in this folded configuration, to enable the dismantled box to be folded again about the fold lines  70 ,  72 ,  74  to reduce it to slightly more than one quarter of the size of the closed pizza box.  FIG. 8  shows this finally-folded condition being approached, and in the final condition the tabs  50  lie adjacent an approximately face-to-face with one another. In this state, the small dove-tail shaped piece of cardboard defined between the cut lines  54  in one of the tabs  50  may be folded out of the tab and engaged in the dove-tail shaped opening provided by displacing the corresponding piece of cardboard in the other tab from the plane of this tab. Hence, the folded pizza box is retained in nearly-flat folded configuration, for easy disposal. 
         [0031]    Having now fully described the present invention in some detail by way of illustration and examples for purposes of clarity of understanding, it will be obvious to one of ordinary skill in the art that the same can be performed by modifying or changing the invention within a wide and equivalent range of conditions and other parameters without resort to undue experimentation without affecting the scope of the invention or any specific embodiment thereof, and that such modifications or changes are intended to be encompassed within the scope of the appended claims. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. 
         [0032]    When used in this specification and claims, the terms “comprises” and “comprising” are synonymous with “including,” “containing,” or “characterized by,” and is inclusive or open-ended. These terms are not to be interpreted to exclude the presence of other features, steps or components. As used herein, “consisting of” excludes any element, step, or ingredient not specified in the claim element. As used herein, “consisting essentially of” does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. In each instance herein any of the terms “comprising”, “consisting essentially of” and “consisting of” may be replaced with either of the other two terms. In the disclosure and the claims, “and/or” means additionally or alternatively. Moreover, any use of a term in the singular also encompasses plural forms. 
         [0033]    All references cited herein are hereby incorporated by reference in their entirety to the extent that there is no inconsistency with the disclosure of this specification. All headings used herein are for convenience only. The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.