GB2174678A - Corner device for a stackable cardboard box - Google Patents

Abstract

Each corner of a stackable cardboard box is formed with a strong solid angle-shaped pillar produced by folding panels (3,4,5) constituting an extension of one side (1) of the box about alternate inward and outward fold lines (6,9,6). The pillar is located at its lower end in a triangular recess (10) in the bottom (7) of the box while its upper end, together with an upwardly projecting portion (8b) of the associated end wall (8) is received in a cap (12) of plastics material which is open at its lower end and is provided, at its upper end, with a stud (12b) for centering the box next about it in a stack of such boxes. <IMAGE>

Description

SPECIFICATION Corner device for a stackable cardboard box Every day, more use is made of cardboard boxes, particularly for transporting fruit and other perishable foodstuffs, and every day endeavours are made to simplify such boxes to reduce their cost and convert them to disposable or single-use boxes. In the majority of cases, the adopted solutions achieve their economy by virtue of a reduction in material but this is at the expense of the strength of the actual box when stacked so that the aforesaid saving is of very limited advantage.

One solution to the problem is to provide a corner device by means of which a strong and effective element is obtained for stacking and at the same time the rest of the box is simplified in the extreme so that it now comprises only a single thickness of material instead of the two or three thicknesses of material which were used hitherto since the main part of the box acts only as a means of containing a specific quantity/weight of a product and for this only a single thickness is required. The result is a very smooth box, the corners of which are reinforced against bursting when stacked with other identical boxes and which, in addition, has the advantage that assembly does not require glueing, stapling or any other of the expedients currently employed.Instead, in each corner of the box there is provided a pillar formed by the superposed bending of a succession of layers which extend the side of the box and the bottom end of the pillar is located in a triangular aperture in the bottom of the box while the top end, together with a projection which belongs to the concurrent end wall fits inside a cap of plastics material in the shape of a prism with a triangular base open at the bottom to receive those parts of the box forming the corner. For its part, the upper surface of each of the caps has a projecting stud which passes freely through the triangular aperture in the bottom corner of the next box up in the stack. In this way, each stacked box is located on the one below by its four corners without any possibility of slippage in any direction or of imbalance which might jeopardise the proper verticality of each stack.

The aforesaid corner device has given very satisfactory results in respect of the types of collapsible and stackable box currently available on the market but consideration has been given to the fact that the folding-over of the successive levels of the extension of the side produced a hollow triangular pillar which to a certain extent reduced the capacity of the box because it constituted a dead space which was repeated in each corner of the box. This disadvantage has been resolved by the improved corner device which is the object of the present invention in which the fold lines which separate the layers which form the pillar are provided in such a way that the layers are connected together in a right angle and form a solid pillar which does not appreciably (as previously) reduce the capacity of the box.

Another improvement affects the corner fixing caps, the edges of which were originally rounded for better fitment on the two or more thicknesses of material of each arm of the rectangular pillar, and consists of an internal sawtooth projection on one of the sides of the cap, the profile of which assists fitment and resists dismantling, which must be performed with a degree of force which may tear the outer facing of the corrugated cardboard portion on which it is mounted. If required, this retaining force may be increased by providing in the surface of the corresponding part of the pillar, a cavity or perforation into which the aforesaid sawtooth projection can be engaged and fixed.

The box blank is provided with the required peripheral cuts and rectilinear fold lines on both sides which will, in the minimum of time, make it possible to make the folds which produce the angular pillar in each corner, raise the sides at a right-angle to the bottom, fit the bottom parts of the four pillars into the four apertures in the corners of the bottom part and finally raise the end walls until they make contact with the pillars and then fit the upper ends thereof inside the retaining caps. And so the box is assembled glueing or stapling and purely by the action of the corner caps which at the same time serve as centring elements to locate the box which is above it in the stack.

For easier understanding of the invention and solely by way of example, it will be described with reference to the accompanying drawing in which: Figure 1 is a plan view of one corner of a box blank; Figure 2 is a plan view of one corner of a box folded from the blank of Fig. 1; Figure 3 shows a part sectional side view and a plan view of a corner fixing cap; Figure 4 is a perspective detail view of the mounting of the top part of the box corner shown in Fig. 2 with the cap in position.

In Fig. 1 it can be seen that the part of the blank adapted to form the side 1 is provided at its outer edge with an inwardly foldable flap 1a defined by slots 2. The side 1 is extended at each end of the flap 1a to provide an upstanding portion 1 b and three panels 3, 4, 5 which have their outer edges flush with that of the portion 1b and are separated from one another and from the side 1 by inward fold lines 6 similar to those which separate the side 1 from the bottom 7 and the latter from the end wall 8, with the exception of panels 3 and 4 which are separated by an outward fold line 9.

Each corner of the bottom 7 is chamfered and forms the hypotenuse of a triangular cavity 10, the sids of which form the inner edges of the side 1 and end wall 8, the cavity communicating with the outside through a slot 11 separating the end wall from the side.

For its part, the end wall 8 also has on its edge an inturning flap 8a defined by grooves 2 and upstanding end portions 8b which on assembly, are positioned outside the panel 3 of the corner pillar formed by folding in the manner shown in Fig. 2.

Fig. 3 shows a mounting cap 12 which receives the upper ends of the parts which contribute to the formation of the angular corner pillar. This cap 12 is a triangular prism with rounded edges which is open at the bottom to receive the parts of the pillar, one of its sides fitting over the projecting portion 1 b of the side 1 and the other over the projecting portion 8b of the end wall 8 and positively engaging the surface of one or the other through the medium of an internal sawtooth projection 12a (Fig. 3). As shown in Fig. 4, on assembly, the acute angles of the prism pass into and penetrate the slots 2 to fit the- vertical edges of the flaps 1 a and 8a of the side 1 and end wall 8, in the event of these being shorter than the shaped corner pillars, which are fitted at their upper ends into the caps 12 while their lower ends are inserted in the triangular recesses 10 in the corners of the bottom 7.

In known manner, the cap 12 has a projecting stud 1 2b at its upper end, the purpose of which is to fit into the corresponding recess 10 in the bottom of the box next above it in a stack of boxes. With this arrangement, each succeeding box has its four corners seated on the top panels of the four caps 12 on the box immediately below so that any relative sliding in a horizontal plane is prevented.

Claims (4)

1. A corner device for a stackable cardboard box of the type in which each corner is formed with a strong pillar produced by the superposed folding-over of a series of panels constituting an extension of one side of the box and located at its lower end in a triangular recess in the bottom of the box, while its upper end, together with an upwardly projecting portion of the associated end wall, is introduced into a cap of plastics material which is open at its lower end and is of triangular prismatic shape, the upper face of the cap carrying a stud for centering the box next above it in a stack, characterised in that the panels forming an extension of the side of the box are separated from one another by alternate inward and outward fold lines so that, when assembled, they constitute a solid angle-shaped pillar.

2. A corner device according to Claim 1, characterised in that at least one side of the retaining cap is provided with an internal sawtooth projection, the profile of which assists assembly and resists removal of the said cap on the top of the corner pillar.

3. A corner device according to Claim 2, wherein retention of the cap on the pillar is increased by providing the surface of the pillar with a recess or perforation for positive engagement by said sawtooth projection.

4. A corner device for a stackable cardboard box constructed and arranged substantially as hereinbefore described with reference to and as shown in the accompanying drawing.