IE68047B1 - Structure of improved stackable container - Google Patents

Abstract

A stackable container consists of a cut and creased blank of a sheet of material, preferably corrugated cardboard, for erection into a box having a rectangular base 1, side walls 2 and end panels 3. Each end panel 3 are provided with a flap 5 which forms a double wall therewith. The flap 5 is separated from the end panel 3 by a strip 8 contained between parallel fold lines (6 & 7 fig. 1), said strip, when flap is folded over acting as a support for another container when stacked. Hinge lug 11 fits into notch 12 and end flap 4 folds around and completely cover the connection (fig. 4). A recess (10, fig 6) is provided in the double wall to aid handling and ventilation. In a modified container (figs 5 & 6) upwardly projecting tabs (13, fig 5) may be provided in the corners, corresponding recesses being provided in the bottom of the container so that they receive the tabs when one container is stacked on another. In an alternative embodiment the inner partitions may be separate pieces.

Description

IMPROVED STACKABLE COCTAINgR This invention relates to an improved stackable container. various kinds of stackable containers in the form of open boxes are already known, which are designed so that when tirey'ZTe placed one on' top of anotherf the resulting load ie stable and can adequately withstand the vertical stresses that the containers must endure during stacking.

Containers are known in which an overhanging flap is provided which extends from the upper border of their shorter sides or end walls, projecting horizontally towards the inside of the container, thus forming a wide ledge which extends without interruption along the entire length of each end wall, and on which another container can rest when placed immediately on top. The stacks thus formed have the disadvantage that the said projecting flaps are not sufficiently strong to withstand the vertical stresses that develop when several containers are piled on top of one another, and the load loses its stability and crushes the packed products .

In order to overcome this drawback, triangular shaped supporting prisms have been arranged in each corner of the container to form props for the said projecting flaps.. - 2 These props partially solve the problem, since they hold up the projecting flaps along the edges, although the centre section remains unsupported. However, they suffer from the disadvantage that they reduce the capacity of the container.

Several attempts have been made in the past to overcome this problem,, In one known container, the corrugated. cardboard sides that support the load are formed fro® two adjoining panels in which the undulations of the corrugated cardboard run vertically, so that the upper border provides a strong, sturdy base for any other containers placed on top of it. This arrangement is also reinforced by means of extensions provided at the ends of the inner panels of the doublewalled sides which adjoin or overlap the upper border of the adjacent side of the container. in another known container, the short sides or end walls of the container have a wide flap extending along the entire length of their upper borders, which folds down inside the container, forming a double wall of the same height as the side wall itself. The aforementioned wide flap has end extensions which adjoin and adhere to the inner surface of the adjacent long side.

This design provides end walls whose upper borders are considerably thickened and act as a base for another container placed on top, this base being partially extended to the longer sides.

The two adjoining panels that make up each end wall are each provided with flaps at each end which are turned orthogonally until they back up against and are glued, one to each side, of the -longer side of- the container, and therefore the ends of these longer sides have three thicknesses of material, forming a very sturdy container.

In yet another known container, the end walls are also double, but in contrast with the preceding example, the inner panel extends from the upper edge of the end wall to approximately half its height. Similarly, its extensions or end flaps are turned orthogonally and fit into recesses or notches made in the longer side walls. The end flaps of each end wall fold round the corners of the container and are glued to the adjacent long side and to the folded flap of the inner partition.

In a still further known container the end flans of the inner panel of the end wall are positioned on the upper edge of the adjacent long wall, in the same vertical plane as the latter, and the respective end. flaps of the end walls which fold round the comers of the container are folded against and glued to both.

The present invention relates to an improved stackable container preferably but not exclusively composed of corrugated cardboard.

According to the invention, there is provided a stackable container comprising a sheet of material with cutting and folding lines marking out a central panel providing a rectangular base wall# side panels to form the main side walls articulating from the longer sides of said rectangular base wall, and panels to form the shorter end walls articulating from the shorter sides of the base wall, these four panels being folded upwardly and defining the area of the container, each end wall panel having an extension of the same sise articulating zrosa its upper border, said extension being separated from the end wall panel by a strip contained between two grooves marking parallel fold lines whereby when said extension is folded over and into the interior of the container, it remains in a vertical position in a plane parallel to the corresponding end wall panel with which it forms a double wall, its free edge resting on the base wall of the container and, in addition, forming on the upper edge of the end wall a longitudinal ledge which acts as a support for another container placed immediately on top, the side edges of said extensions of the end wall panels being provided with projections at each end which are folded to engage with the adjacent side wall panel in the same plane as said panel, the longer side panels of the container having recesses at each end in the top edges thereof which are covered on the outside by end flaps extending from the side edges of the shorter end walls.

The preferred container comprises an open», stackable rectangeiax box, two parallel sides of which, he they the longer sides or the end walls» are formed by two homologous panels, in which the corrugations of the cardboard run vertically» abutted together tc> fora a double wall» the upper border providing a ledge which acts as a base to give safe support to another or other containers placed immediately on top of it.

The projections are preferably folded through 90°, and inserted into the matching recesses cut out from the corresponding end of each adjacent side wall, with which they are perfectly aligned on both sides and along the upper edge.

The flaos are preferably folded round the corresponding corner of the box to adhere to the adjacent side wall and to the extension aligned with it, the upper edge of the double wall that constitutes th© base for another box placed on top being partially extended to provide locating means along the upper border of the adjacent sides. The locating means can be in the form of tabs or projections allowing the fitting of one box over another and thereby avoiding dangerous lateral displacements during stacking which would endanger the stability of the loads formed.

S The invention will now be described by way ©£ example only, with reference to the accompanying drawings, in which: FIGURE 1 is a fragmentary view showing a comer of a 10 container blank including means for inserting one box over another situated immediately underneath it; FIGURE 2 is a fragmentary view showing the container of Figure 1 during the assembly phase; FIGURE 3 is a fragmentary view of the box of Figure 2, after assembly, viewed from the inside; FIGURE 4 is an external view of a corner of the container 20 shown in Figures 2 and 3 after assembly; FIGURE 5 is a view showing a comer of a modified container; and FIGURE 6 is an external view of the comer of the container shown in Figure 5.

Referring now to the drawings, there is shown a container blank made of corrugated paper or cardboard having a base 1 with longer side walls 2 and shorter end walls 3 provided with extensions at their ends to form flaps 4 which are folded round to enclose the comers ox the container.

A wide flap 5 articulates tbs upper border of the end wall 3 and has the same measurements as the end wall 3. It is folded over towards the inside of the container to be positioned vertically and parallel to the end wall with which it forms a double wall. The end wall 3 and the flap 5 have the channels of the corrugated material of which they are made running vertically, resulting in a wall of considerable mechanical strength and ideal for effectively bearing the vertical stresses that develop when several containers are stacked on top of each other.

The articulation between each end wall 3 and its wide flap 5 is carried out by means of two fold lines 6,7 defining therebetween a strip 8 which forms a wide ledge on the top edge of each end wall 3 on which another container can stand firmly.

As can be seen from Figures 1, 5 and 6, a cut-out 9 is formed in each end wall 3 and flap 5 which fulfils two functions- Firstly it forms an opening or recess between every two stacked containers to provide an air passage to ventilate the packed products and secondly, it provides a recess 10 (see Figure 6) which permits a handler's fingers to be inserted between every two containers for carrying purposes.

Extensions in th® form of tabs 11 are provided on each side edge of each flap 5 which, when the flaps 5 are folded down, move down with them and axe deflected orthogonally to fit into a notch or recess 12 in the top edge of each of the longer side walls 2, being perfectly aligned with said longer side walls, on either side, and level with the top edge, as shown in Figures 3 and 5.

The assembly formed by the two longer side walls 2, the end walls 3 with their double inside wall 5 and the tabs 11 inserted into recesses 12 in the longer side walls 2 of the box, form the corners of the container, and wide flaps 4 hinged at the respective side edges of the main outer panels of the end walls 3 and folded round the corners as shown in Figures 4 and β. These flaps 4 are joined, preferably by means of adhesive, to the adjacent long side walls 2 and to the tab 11 inserted into the notch or recess 12 therein so that it is invisible from the outside.

Referring now to th® modified container of Figures 5 and 6, it can be seen that additional locating means in the form of tabs 13 project upwardly from the upper corner edge of the container to form a dihedral angle, one wing of which is situated on the end wall 3 of the container and the ocher on the adjacent main side wall 2. These tabs 13 can fit into a recess 14 in the lower border of the corner of another box when placed or -fcop> which ds -held between the four const tabs of the container placed immediately below. The tabs permit the successive fitting of one box over another and thus stabilise them when they axe placed one on top of one another in stacks. Boxes fitted into one another using these co-operating corner tabs 13 and recesses 14 enable loads of a considerable height to be formed without any lateral displacement.

The container just described has been designed so that it may be assembled entirely by machine, without the intervention of manpower, and this is a considerable advantage. The containers thus formed are equipped with sturdy means of stacking and avoid the need to provide triangular supporting prisms in the comers which reduce the capacity of the assembled container to a large extent.

The retention of the inner panel 5 of the end walls 3 inside the container is carried out simply by inserting the lateral tabs 11 into the notches or recesses 12 in the longer side walls 2. The end flaps 4 which fold round the corners of the container, completely cover the connection between the tabs 11 and the longer side walls 2 which is therefore not visible from the outside.

Another advantage of the container described is that the upper edge of the end wall, owing to its sturdy character, provides a very strong, stable base to give effective support to the weight of one or more containers placed on top. This base also extends along th® ©ads of th® upper border of the longer side walls, increasing the supporting surface between containers.

Claims (7)

1. A stackable container comprising a sheet of material with cutting and folding lines marking out a central panel 5 providing a rectangular base wall, side panels to form the main side walls articulating free the longer sides of said rectangular base wall- and panels to form the shorter end walls articulating from the shorter sides of the base wall, these four panels being folded upwardly and defining the 10 area of the container, each end wall panel having an extension of the same size articulating from its upper border, said extension being separated from the end wall panel by a strip contained between two grooves marking parallel fold lines whereby when said extension is folded 15 over and into the interior of the container, it remains in a vertical position in a plane parallel to the corresponding end wall panel with which it forms a double wall, resting its free edge on the base wall of the container and, in addition, forming on the upper edge of the end wall a 20 longitudinal ledge which acts as a support for another container placed immediately on top, the side edges of said extensions of th© end wall panels being provided with projections at each end which ara folded to engage with the adjacent side wall panel in th® same plane as said panel, 25 the longer side panels of the container having recesses at each end in the top edges thereof which are covered on the outside by end flaps extending from the side edges of the shorter end walls.

2. A stackable container according to claim 1 wherein each recess in the longer side walls is covered on the outside and open on the inside and forms a cut-out which receives and retains the matching projection which articulates from each side edge of the folded-down extensions that form the inner wall of each double end wall.

3. A stackable container according to claim 2 wherein the projections fit into the recesses in the longer side walls from the interior of the container and are retained therein by retaining means.

4. A stackable container as claimed in claim 3 wherein the retaining means is an adhesive.

5. A stackable container according to any preceding claim wherein the top edges of the projections are level with the longitudinal ledge formed on the upper border of the end walls to provide an extension of said ledge with the upper border of the corners of the container.

6. A stackable container according to claim 1 wherein, the upper border of the end walls and the projections which fold around the main side walls include tabs at a dihedral angle of 90° which project upwardly from each corner of the container, the lower edge of each corner also being provided with recesses matching the shape and capacity of said tabs.

7. A stackable container substantially as herein described with reference to Figures i-4 or Ficutes 5 and 6 of the accompanying drawings.