A container of this type has already been described by the present applicant in patent application PCT/IB01/02195.

During the operations of stacking the containers in question, it is very difficult to arrange the containers on top of each other and/or adjacent to each other in an exactly rectilinear way.

It is usually necessary to carry out a number of subsequent position adjustment operations, which cause a loss of time and increase the probability of damaging a container or its contents.

Furthermore, if the containers are not stacked accurately, conditions are created in which it is possible that the container or containers which have to withstand the load of numerous other containers placed on top of them may be deformed or damaged, as mentioned above.

The inventor of the present invention has devised a

container provided with means for"automatic"accurate alignment in the vertical or transverse direction between different containers stored in a single storage area.

These means consist of parts formed on or fitted to the outer surfaces of the various faces of a container according to the invention, which are exactly aligned with the identical parts of another identical container placed on top of the first container or placed side by side with it.

The aforesaid parts are made in such a way as to have a plurality of successive recesses and projections, and in such a way that the recesses and projections present on each face of the container, and forming a pair with another face positioned parallel to and opposite the first face, are exactly complementary to the recesses and projections present on the other face forming the same pair.

The aforesaid parts are also positioned in such a way as to be exactly aligned with each other, and thus, when the said recesses and projections of two parts of two identical containers placed side by side or one on top of the other penetrate into each other in a complementary way, this means that the two containers are also exactly aligned (in the vertical direction by the action of the recesses and projections present on the horizontal faces, and in the horizontal direction by the action of the recesses and projections present on the vertical faces).

The inventor considers that the most advantageous solution is that of making the said parts with a plurality of complementary recesses and projections in the shape of regular pyramids or truncated pyramids

with square bases. Therefore, because of the effect of the inclined plane formed by their oblique faces, the complementary recesses and projections of the said facing parts penetrate into each other when the two parts are pressed against each other, thus providing exact alignment between the parts and therefore between the containers to which they are fixed.

Whereas the pressure between two parts fitted to the facing horizontal faces of two containers, where one is placed on top of the other, is exerted simply by the weight of the upper container, the pressure between two parts fitted to the vertical faces can be provided by pushing one container towards the other manually or by the means used for moving the containers.

Consequently, the object of the present invention is a container as described in the attached Claim 1.

A more detailed description of a preferred example of embodiment of the container according to the invention will now be given, with additional reference to the attached drawings, which show: in Fig. 1, a perspective view of the said example of embodiment of a container according to the invention ; in Fig. 2, an enlarged perspective view of the container of Fig. 1; in Fig. 3, a longitudinal section through only the parts with recesses and projections of two horizontal faces, brought together, of two containers of which one is placed vertically on top of the other, where the containers are not exactly aligned ; in Fig. 4, the longitudinal section of Fig. 3, where the recesses and projections have penetrated into

each other in a complementary way, producing an accurate vertical alignment of the two containers.

Fig. 1 shows how a container 1 according to the invention has the usual parallelipedal shape comprising four vertical faces 2,3, 4,5 and two horizontal faces 6,7. On each of the outer surfaces of all the faces 2,4-3, 5-6,7, forming pairs parallel to and opposite each other, there are formed (by simple moulding if the container 1 is made from plastic material) or fitted one or more parts 8i, 9i (the parts 8i, 9i on the lower horizontal face 6 and on the vertical face 5 are not visible in the drawing, but are located in positions which are mirror images, with respect to the container 1, of those of the parts 8i, 9i present on the identical opposite and parallel walls 7,3) each having a plurality of complementary recesses 10i and projections lli, as shown more clearly in Fig. 2, formed in such a way that two parts of two different containers (shown in one of Figures 1 and 2) face each other exactly when the two containers are placed side by side in such a way that the projections lli of one part present on one container are made to penetrate in a complementary way into the recesses 10i of the facing part present on the other container. Figures 3 and 4 show more clearly what has been explained above: the recesses 10i and the projections lli are in the form of regular pyramids or truncated pyramids with square bases, the sides of the bases being, in this case, parallel to those of the faces 6,7 on which they are formed or to which they are fitted.

When, during an operation of stacking two containers 1, 1', the upper container 1 is placed on the underlying container 1'with an error in positioning in the transverse direction equal to the distance Q between

the vertices of two facing projections lli as shown in Fig. 3, the inclined plane effect between the faces of the opposing projections lli of two of the said parts 8i in contact with each other is such that, because of the weight P of the upper container 1, this container is subjected to a lateral thrust S which causes the projections lli to be inserted in a complementary way into the recesses 10i, resulting in the alignment of the said vertices of the projections and recesses, as shown in Fig. 4, and the desired exact positioning of the containers 1, 1'with respect to each other. From simple geometrical principles, it can be deduced that the alignment described above is produced by the inclined planes in all cases in the presence of positioning errors smaller than the distance R between the vertices of a recess and a projection which are adjacent to each other, in other words in the presence of errors smaller than half of the base side of the pyramids or truncated pyramids described above in the case examined here.

The same considerations apply to the coupling between recesses 10i and projections lli of parts 9i fitted to the lateral faces of containers placed side by side (a case not shown in the drawings), with the sole difference that, as indicated above, the thrust P due to the weight must be replaced with a thrust exerted on one of the containers.

Clearly, the shapes of the complementary projections lli and recesses 10i can be different from those described above and illustrated in Figures 3 and 4.