Abstract:
A stackable knock down box is provided for the bulk transportation and storage of fresh produce such as fruit. The box comprises a base pallet, and six side wall panels which are hinged together to define a composite side wall enclosure which can be folded into a stack. A number of drop-away base clip arrangements are provided for releasably holding the composite side wall enclosure to the base pallet in both its erected and folded conditions. The box can be stacked in both the erected and folded conditions, and includes a number of panel aligning inserts located at the upper edge corners of the side walls. Each panel aligning insert is formed with an angled contact face which slopes downwardly and outwardly. A number of complemental panel aligning formations are formed within pedestals on the pallet, and have an angled contact face which slopes upwardly and inwardly. As a result, inter-engagement of the contact faces results in the upper edges of the side walls being urged inwardly into inter-engagement with the complemental panel aligning formations.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    THIS invention relates to a stackable knock down box which is primarily but not exclusively intended for the bulk transportation and storage of fresh produce such as fruit.  
           [0002]    Packaging for fruit and other fresh produce is expensive, particularly in the case of sacrificial packaging which has to be disposed of after a single use. In many countries which import fruit, it is obligatory for the supplier in one way or another to dispose of the fruit packaging.  
           [0003]    It is accordingly desirable to provide a knock down bulk fruit box which is reusable, and which can be stacked both when folded and erected. One requirement of such a re-usable box is that it needs to be sufficiently rugged to withstand repeated use and abuse in the erected and folded conditions, particularly when stacked.  
         SUMMARY OF THE INVENTION  
         [0004]    According to a first aspect of the invention there is provided a stackable knock down box comprising a base including a base panel supported on a plurality of pedestals, a plurality of side wall panels, hinge means connecting the side wall panels together to define a composite side wall enclosure, the hinge means being adapted to enable the wall panels to be folded into a stack, and a plurality of base clip arrangements for releasably holding the composite side wall enclosure to the base in its erected and folded conditions, the knock down box being stackable in both the erected and folded conditions, and including upper panel alignment and box support means provided along the operatively top edges of the side wall panels, and complemental lower panel alignment means provided on the base, with the upper panel alignment and box support means of a subjacent box being arranged to interengage with and to nest within the lower panel alignment means of a superjacent box when the erected boxes are stacked on top of one another.  
           [0005]    Preferably, the upper panel alignment and box support means are located towards the outer corners of the composite side wall, and the lower panel alignment means include complemental corner recesses on the pedestals.  
           [0006]    Conveniently, the upper panel alignment means comprises a plurality of panel aligning formations each formed with an angled contact face which slopes downwardly and outwardly, and the lower panel alignment means comprises a plurality of complemental panel aligning formations each formed with an corresponding angled contact face which slopes upwardly and inwardly, such that interengagement of the contact faces results in the upper edges of the side walls being urged inwardly into firm nesting interengagement with the complemental panel aligning formations.  
           [0007]    Typically, mounting means are provided for holding the base clips captive on the base.  
           [0008]    Advantageously, the base clips comprise drop-away substantially L-shaped sprung clips which each have a lower pivoting end held captive within a clip-retaining assembly in the base panel and an upper end terminating in an inwardly facing tang which are releasably engageable with horizontal locating slots formed towards the lower edges of the side wall panels.  
           [0009]    Advantageously, outer corner faces of the pedestals carry corner reinforcing brackets which are formed with upper inwardly directed tangs constituting base clip arrangements which are engageable with horizontal locating slots formed towards the lower corner edges of the side wall panels.  
           [0010]    The brackets are preferably formed with lower inwardly directed flanges which extend into the corner recesses and form part of the lower panel alignment means.  
           [0011]    According to a second aspect of the invention, there is provided a stackable knock down box comprising a base including a base panel supported on a plurality of pedestals, a plurality of side wall panels, hinge means connecting the side wall panels together to define a composite side wall enclosure, the hinge means being adapted to enable the side wall panels to be folded into a stack, and a plurality of base clip arrangements for releasably holding the composite side wall enclosure to the base in both its erected and folded conditions, the hinge means comprising first and second hinge plates joined together by means of a pivot assembly and arranged to be mounted to the operatively outer surfaces of the adjacent side wall panels by means of fixing elements, each of the hinge plates terminating in inwardly projecting tangs for locating in corresponding slots in the adjacent side wall panels so as to relieve shear stress on the fixing elements arising from an outwardly directed force being exerted on the wall panels when in an open condition.  
           [0012]    Conveniently, the pivot assembly is recessed relative to the outer corner faces of the composite side wall enclosure and defines a pivot axis which is locatable in the region of an intersection of the operatively inner surfaces of the adjacent side wall panels, with the hinge plates being formed with inwardly angled connecting webs or fingers extending inwardly between the outer faces of the hinge plates and the pivot axis.  
           [0013]    Advantageously, each of the first and second hinge plates are formed with at least one aperture for receiving the fixing elements, with the aperture conveniently being surrounded by an annular protective boss, and the pivot assembly comprises a hinge pin and a plurality of interdigitating plate fingers extending from each of the webs and scrolled around the hinge pin.  
           [0014]    Typically, the knock down box is a two part box, with all the box components being carried either on the base or the composite side wall.  
           [0015]    Locating means are typically provided on the base for locating the stacked composite side wall.  
           [0016]    Preferably, overhanging strike plates are fitted to at least one of the side wall panels for allowing the base clip arrangements to ride up and over the strike plates to clamp the composite side wall to the base.  
           [0017]    Optionally, the box includes an intermediate foldable shelf assembly providing horizontal partitioning for the box.  
           [0018]    In a preferred form of the invention, the pedestals are fitted with skid planks which are arranged to nest completely within a subjacent box.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 shows a perspective view of a first embodiment of an assembled box of the invention;  
         [0020]    [0020]FIG. 2 shows a front elevation of one of the box wall panel hinges of FIG. 1;  
         [0021]    [0021]FIG. 3 shows a sectioned plan view of a corner hinge of the box along the line  3 - 3  of FIG. 1;  
         [0022]    [0022]FIG. 4 shows a perspective view from below of one corner of the base portion of the box of FIG. 1;  
         [0023]    [0023]FIG. 5 shows a fragmentary sectioned side elevation of the base and a side wall of the box of FIG. 1 illustrating the clip arrangement for holding the base and side walls together;  
         [0024]    [0024]FIG. 6 shows a perspective view from above of the FIG. 1 box in its knocked down condition;  
         [0025]    [0025]FIG. 7 shows a perspective view of a second embodiment of an assembled box of the invention;  
         [0026]    [0026]FIG. 8 shows a perspective view of the box of FIG. 7 in the knocked down condition;  
         [0027]    [0027]FIG. 9 shows a perspective view of the box of FIGS. 7 and 8 in a semi-erected condition;  
         [0028]    [0028]FIG. 10 shows a top corner perspective detail of a hinge and a pair of panel aligning formations forming part of the box of FIG. 7;  
         [0029]    [0029]FIG. 11 shows a cross-sectional view of the hinge on the line  11 - 11  of FIG. 10;  
         [0030]    [0030]FIG. 12 shows a cross-sectional detail of a pair of erected boxes of FIG. 7 in a stacked position;  
         [0031]    [0031]FIG. 13 shows a perspective view from below of one corner of the base portion of a box of FIG. 7;  
         [0032]    [0032]FIG. 14 shows a partly cut-away side view of a stack of knocked down boxes of FIG. 8;  
         [0033]    [0033]FIG. 15 shows an underplan view of a third embodiment of an assembled box of the invention;  
         [0034]    [0034]FIG. 16 shows a side view of a pallet forming part of the third embodiment of FIG. 15;  
         [0035]    [0035]FIG. 17 shows a side view of part of a fourth embodiment of a box of the invention incorporating a shelf, and  
         [0036]    [0036]FIG. 18 shows a top plan view of the shelf of FIG. 17.  
     
    
     DESCRIPTION OF EMBODIMENTS  
       [0037]    A first embodiment of a box  10  of the invention is shown in FIG. 1 to include a base  12 , six support pedestals  14  which are attached to the base, and a composite side wall  16 . The side wall  16  includes three pairs of opposed side wall panels  18 ,  20  and  22 . The side wall panels are joined to one another by hinges  24  and spring clips  26 . The upper edges of the wall panels, at the corners of the box, are covered with sheet metal reinforcing elements  28  which are fixed to the panels. The wall panels additionally include horizontal slots  30  adjacent their lower edges at the corners of the box. The side wall spring clips  26  are right angled and carry spring clip formations which are releasibly engageable in vertical slots  31  in the panels adjacent their corners. One leg of each of the spring clips  26  is fixed to one of the panels by means of rivets or the like.  
         [0038]    The hinges  24  are more clearly seen in FIGS. 2 and 3 with the hinge  24 A of FIG. 2 being a hinge between two of the panels  20  and  22  and the hinge  24 B of FIG. 3 a corner hinge. Each leaf  32  of the hinge is double sided, as is shown in FIG. 3, so as to embrace the panel to which it is attached by means of rivets  34 . The outer of the two leaf plates of each leaf has a raised annular formation  35  which surrounds and extends above the head of the rivets  34  to protect the rivets from handling damage. The hinge pins  36  are, again as shown in FIG. 3, offset from the centre of the panels to be located in cut-outs  37  in the panels to ensure that the hinges are recessed from the outer surface of the wall panels for protection against damage.  
         [0039]    The base  12  of the box, as is better seen in FIG. 6, consists of a flat panel  38  which has two cut outs  40  in each edge for providing vertical ventilation through the box  10  when assembled. The spacing between the base pedestals  14  allows for four-way entry for a 90 mm high pallet-jack.  
         [0040]    As is clear from FIG. 5, the edges of the base panel  38  between the cut outs  40 , which in use are below the wall panels  20  and  22 , are rebated to provide steps  41  having a width corresponding to the thickness of the panels  20  and  22  so that the lower panel edges are locatable in the recesses when the box is assembled. The purpose of this arrangement is for the vertical face  41 A of the step  41  to provide a stop against which the inner faces on the hinged panels  20  and  22  may abut to prevent the hinged walls from folding inwardly into the assembled box.  
         [0041]    The construction of the pedestals  14  is more clearly seen in FIG. 4 where the pedestals are shown to consist of compressed wooden blocks  42  which are releasibly attached to the base panel  38  by means of screws for simple replacement. The outer facing surfaces of the blocks  42  are recessed as shown in FIG. 4 by a distance slightly greater than the thickness of the wall panels of the box. The underside of the block  42  carries a projecting foot  44  which is made from a robust plastics material. The upper surface of the base panel  38 , as shown in FIG. 6, is provided with recesses  46  above each of the pedestals  14  and in which the pedestal feet  44  are engageable when knocked down boxes are stacked one on the other. Importantly, the outer surfaces of the pedestals at the corners of the box are armoured by right angled brackets  48  which have lower inwardly directed aligning flanges  50  which are located against the reccessed edges  51  of the pedestal blocks and upper inwardly directed flanges  52  which are releasibly engageable in the slots  30  at the lower edges of the wall panels.  
         [0042]    The underside of the base panel  38  carries hard wood skids  54  to minimise fork lift damage to the underside of the boxes. The base panel  38  is held to the composite side wall  16  of the box by means of not only the flanges  52  on the brackets  48  but additionally by spring clips  56  which are shown in greater detail in FIG. 5. The clips  56  are attached to the base plate  38  of the box by means of a hinge type arrangement  58 . The hinge type arrangement comprises an apertured retaining plate  59  which is formed with a retaining tang  59 A extending into a slot  59 B formed in the base panel. The scrolled end  56 A of the sprung clip is held loosely and hingedly captive behind the tang  59 A. The inwardly directed tang  56 B at the free end of the clip is releasibly engaged, in the same manner as the clips  26 , in slots  60  in the panels  20  and  22 .  
         [0043]    To dissemble the box from its erected position in FIG. 1, downward pressure is applied to the base of the box within the box adjacent the wall panels  20  and  22  to disengage the panels from the base steps  41  and the upper portions of the spring clips  26  which are not permanently anchored to the wall panels are pried from the grooves  31  in which they are located to release the wall panels from each other at the comers of the box. The spring clips  56  are similarly freed from the slots  60 . The hinged joins between the wall panels  20  and  22  of the composite side walls, which are now free of the base steps  41 , are now pressed towards one another to pull the panels  18  towards each other until the panels are in their stacked configuration. The stacked panels are now laid on the base panel  38  as shown in FIG. 6 with the drop away clips  56  engaged with the uppermost panel to hold the stacked side wall panels to the base panel. To again erect the box the knock down procedure described above is merely reversed.  
         [0044]    In use, two or more of the filled boxes  10  are stacked one on the other with the aligning recessed portion  51  of the pedestals of the upper box located on the inside of and resting on the reinforcing elements  28  at the corner edges of the box to hold the upper box engaged with the lower box against relative sideways movement of the stack boxes. After use the boxes are knocked down as described above with one knocked down box, as shown in FIG. 6, located on another below it with the feet  44  of the pedestals engaged in the recesses  46  of the base panel below it again to resist any sideways dislocation of the stacked boxes during transit.  
         [0045]    All of the box panels, in this embodiment of the invention, are made from plywood which is bonded with boil-proof fenal formaldehyde resin and coated with modified phenolic impregnated high density resin film on both sides. The film stiffens the plywood, gives it a great degree of abrasion and impact resistance, and while it enhances the appearance of the box it also makes the surface completely impervious to moisture. The edges of the panels are sealed with epoxy paint. Treated in this manner the box components are easily able to withstand relatively high temperatures and also allow the bins to be steam cleaned for reuse.  
         [0046]    Referring now to FIG. 7, a second embodiment of a box  70  includes a base panel  72 , six support pedestals  74  attached to the base panel, and a composite side wall  76  which includes six panels arranged in opposed pairs  78 A and  78 B,  80 A and  80 B and  82 A and  82 B. The panels are joined to one another by corner hinges  84  and inwardly folding side wall hinges  86  connect adjacent panels  80 A and  82 A and  80 B and  82 B. Sheet metal aligning and reinforcing elements  88  are rivetted to the upper edges of the panels at the corners of the box, as well as mid-way along the side wall panels  78 A and  78 B. The side wall panels are provided with horizontal corner slots  90 , intermediate clip-receiving slots  92 , and an array of ventilation slots  93 . The base panel  72  is similarly provided with ventilation slots  93 A.  
         [0047]    The corner hinges  84  and the aligning and reinforcing elements  88  are more clearly visible in FIGS.  10  to  12 . The corner hinges  84  comprise a pair of hinge plates  96  and  98  formed from sheet metal. Inwardly angled interdigitating fingers  100  are scrolled at the ends to accommodate a central hinge pin  102 . Each of the hinge plates terminate in tangs  104  which extend inwardly at right angles from the hinge plates  96  and  98  and which locate in corresponding slots  106  defined in the panels. The hinge plates  96  and  98  are connected to adjacent panels  82 A and  78 B by means of aluminium rivets  108 , and are formed with protective annular bosses  110  within which an outermost head  112  of each of the rivets is countersunk so that the rivets are protected against handling damage.  
         [0048]    The hinge pin  102  is offset from the centre of the panels and is located at the intersection of the inner faces  82 A 1  and  78 B 1  of the respective panels  82 A and  78 B so as to allow the panels to be folded together into an overlying stacked condition. This is achieved by forming protective rectangular cutouts  114  in each of the panels. The cutouts are formed with chamfered bases  116  against which the inwardly angled fingers  100  of the hinges rest. The tangs  104  perform an important stress-relieving function, in that, in the event of the hinge being subjected to outward stresses, these stresses are not only borne by the rivets  108  bearing against the relatively small areas of the rivet holes in the panels, but also by virtue of the tangs  104  bearing against the inner faces of the slots  106  to take up and distribute the stresses. As a result, the hinges are still functional and tend to stay in position, even in the event of a particular rivet being damaged or even working loose completely. As the hinge plates  96  and  98  are anchored against the outer faces  78 B 2  and  82 A 2  of the respective panels  78 B and  82 A, they are far better configured to absorb outward pressure or impact in the direction of arrows  117 . This would not be so were the hinge plates  96  and  98  located on the inner surfaces  78 B 1  and  82 A 1  of the panels, as would be applicable in the case of a conventional hinge, where the hinge plates are mounted to those panel faces which fold towards one another.  
         [0049]    [0049]FIGS. 10 and 12 clearly illustrate how the sheet metal reinforcing and aligning elements  88  are rivetted to the top edge comers of adjacent side walls of the box by means of rivets  112 A, the heads of which are similarly located within protective raised annular formations  110 A. The reinforcing and aligning formations  88  are substantially U-shaped and are formed with angled contact faces  119  which slope downwardly and outwardly at an angle of about 20° from the horizontal, and fit snugly over the complementally chamfered top edges  120  of the side wall panels.  
         [0050]    Each of the pedestals  74  is similarly fitted with a complemental reinforcing and aligning insert  121  which forms the lowermost portion of an angled reinforcing bracket  122  which is screwed to the base panel  72  and each of the corner pedestals  74  by means of wood screws  124 . The outer facing surfaces of the pedestals  74  are formed with recesses  126  which are slightly deeper than the thickness of a wall panel of the box. The recesses  126  are provided with an overhanging top face  128  which is angled downwardly and outwardly so as to accommodate the corresponding inwardly and upwardly angled contact face  130  of the complemental reinforcing and aligning insert  121 . In FIG. 12, it is clearly apparent how the complementally angled contact faces  116  and  130  of the panel aligning formations result in the upper edges of the side walls of a subjacent box being forced inwardly in the direction of arrow  131  when a superjacent box is stacked on top of it. All of the corners of a subjacent box will thus be urged inwardly, even when there is initial misalignment of a superjacent box, with misalignment of up to a wall thickness or more being catered for by progressive interengagement of the complementally sloping contact faces  130  and  116 . The intermediate reinforcing and aligning elements  88  on the side walls  78 A and  78 B will similarly be pulled inwardly by virtue of screw-in side brackets  131 A being provided with upwardly and inwardly angled contact faces which are identical in cross-section to those illustrated in FIG. 12. The aligning inserts serve to relieve outward pressure on the corner hinges  84 .  
         [0051]    Referring now to FIG. 8, the box  70  is shown in a knocked-down configuration in which drop-away L-shaped spring clips  132  are used to clamp the composite side wall  76  to the base  72  of the box. Pairs of strike plate formations  113 A and  113 B are riveted to the outer surface of the side panel  78 A along opposite side edges thereof.  
         [0052]    In FIG. 9, the knock-down box  72  is shown in an intermediate position in which the composite side wall  76  is being folded into a flat condition. The base panel  72  is provided with scalloped ventilation cutouts  134 , and stepped recesses  136  locate the lower edges of the side walls  80 A,  82 A,  80 B and  82 B when the box is erected. Both the corner brackets  122  and the side brackets  131 A are formed respectively with inwardly directed tangs  138  and  140  which locate within the respective complemental slots  90  and  92  to clamp the composite side wall to the base when the box is erected. As is clear from FIG. 13, the pedestals  74  are provided with glide feet  142  which locate within complemental circular recesses  144  when the knocked down boxes are stacked on top of one another.  
         [0053]    The erected box of FIG. 7 is knocked down in the following manner. A levering tool  146  is provided with an L-shaped blade  148 , the end of which is wedged between one of a pair of raised access openings  94 B defined in each of the clips  132  and the adjacent side panels. The tangs  132 A of the clips are then levered out of the slots  92  so that the clips drop away into the FIG. 9 position. The side panels  80 A and  82 A and  80 B and  82 B are raised so that their lower edges ride over the stepped recesses  136 , and the major side panels  78 A and  78 B are disengaged from the bracket tangs  90  and  92  and pushed inwardly towards one another so that the entire composite side wall  76  is folded together into a double-M stackable configuration in the manner illustrated in FIG. 9. The composite side wall is then located on top of the base  72  and the clips  132  are then forced upwards and inwards so that the tangs  132 A ride over the outer faces of the downwardly depending legs  150  of the L-shaped strike plates  113 A and  113 B.  
         [0054]    Each of the strike plates  113 A and  113 B is provided with a fixed leg  152  which terminates in a tang  154  which locates within a complemental slot  156  located in the side panel  78 A. A similar tang  158  projects from the downwardly depending leg  150  of each of the strike plates, and locates within complemental slots  160  defined within the outer faces of the side panels  80 A and  80 B when the box is in the erected FIG. 7 condition. The tangs  158  are freed from the complemental slots  160  as the box is folded into a stacked configuration, as can clearly be seen in FIG. 9. The strike plates  113 A serve to cover the irregular stacked profile of the side edges of the composite side wall  76  and allow the tangs  132 A to ride up over the smooth outer faces of the legs  150  of the strike plates. Each of the strike plates are formed with a pair of raised bosses  162  on their corners  164  between the legs  150  and  152 . The bosses serve a retaining function for retaining the tangs  132 A in the FIG. 8 position in which they ride up and over the bosses and locate against the upper face of the leg  152 . The leg  152  is formed with a rivet hole surrounded by an annular protective boss  166 .  
         [0055]    Referring back to FIG. 9, the base  74  is formed with four elongate boss-locating cut-outs  168  which serve to locate the annular bosses  110  on the corner hinges  84  which are fitted to the side panels  78 B. The recesses  168  thus serve to prevent the folded composite side wall  76  from sliding around on top of the base  72 . In addition, they serve to register the composite side wall on the base in such a way that the strike plates  113 A are in vertical alignment with the drop-away clips  132 .  
         [0056]    Referring now to FIG. 14, a stack of knocked down boxes  70 A,  70 B,  70 C and  70 D is shown. The height h1 of the stacked composite side wall  76  is marginally less than the height h2 of 85 mm of the pedestals  74 , with the result that the knocked down boxes can be stacked on top of one another with the feet  142  of an overlying box locating snugly within the complemental circular recesses  144  formed in an underlying box and the base  72  of an overlying box straddling the stacked composite side wall  76  of an underlying box. The overall effective height h3 of a stacked container is reduced by the fact that the foot  142  nests within the complemental recess  144  in an underlying knocked down box or container. This reduces the effective height of each container by the 10 mm height of each foot  142 , and results in twenty knocked down boxes occupying a total height of only 2.1 m. The feet  142  are formed from a nylon material and have a smooth finish. An important advantage of this is that the feet  142 A of the lowermost container are able to glide on the loading surface with far less frictional resistance than the wooden block  74  on which the feet are mounted. The feet thus allow a box to glide more easily on the loading surface when such a box is mishandled by the tines of a fork lift truck, rather than allowing the tines to penetrate the side walls of a loaded box, which often tends to occur in the case of heavily loaded boxes or stacks of boxes which are not fitted with glide feet  142 .  
         [0057]    In an alternative form of the invention illustrated in FIGS. 15 and 16, where stacked boxes require greater stability for loading on conveyors, flat bed trucks and the like, the glide feet are replaced with a pair of parallel skid planks  170  which are screwed onto the three outermost rows of blocks  74 . Naturally, the stacked height of such boxes is significantly increased as the skid planks  170  sit on the underlying base panels  72 . The side and end edges of the skid planks are flush with the corner blocks so as to allow the skid planks, together with the blocks, to nest snugly within the top opening of a subjacent container when the boxes are erected. The top edges of the skid planks are formed with chamfers  172  for enabling easier access for wheeled hand pallet trucks.  
         [0058]    As is clear from FIG. 15, the base plate  72  is fitted with four clip-retaining plates  174  which are substantially C-shaped in form, and which hold the scrolled ends of the drop-away clips  132  loosely and hingedly captive in the same manner as the retaining plates  59  of FIGS. 4 and 5.  
         [0059]    Referring now to FIGS. 17 and 18, a still further version of a box is shown which is provided with an intermediate shelf  176 . The shelf  176  is formed from two folding panels  176 A and  176 B which are hinged together by means of straight hinge assemblies  178 . The shelf  176  rests on a pair of wooden support cleats, one of which is shown at  180 , which are bolted to the central interior faces of the side panels  78 A and  78 B. Additional support is provided by tongues  182  which extend from the free edges of the shelf panels  176 A and  176 B, and which are chamfered to allow them to locate firmly within horizontal slots formed at the correct height within the end panels  80 A,  82 A,  80 B and  82 B. The shelves are provided for transportation of fruits which tend to bruise easily, and which cannot be stacked at a height greater than half the height of the box. The shelves do not form part of the stowed assembly illustrated in FIG. 8. Rather, during transportation of the stacked boxes, approximately twenty shelves are stowed separately in an erected box.  
         [0060]    The box of the invention has a particularly rugged construction arising from the structure of the hinges, the corner and side brackets and the reinforcing and aligning elements. The stackability of the box in the knocked down and erected conditions and the sturdiness of the knocked down and erected stacks allows the box to be readily and repeatedly transported both when knocked down and erected. In addition, as the box is essentially two-part in form, with no loose components, the possibility of components being mislaid during transit is eliminated.