For some time now, drums, i. e. containers usually made of cardboard, have been used for containing washing powders.

They are particularly low-cost in view of the material from which they are made ; moreover, they are also very practical now that the cylindrical shape has been abandoned in favour of the shape of a parallelepiped.

In order to open the drums of the known type, the top part of their sides is provided perimetrally with a tearing zone pre-cut in the thickness thereof.

Once said zone has been torn, the drum has a lid which can be removed as required, but, owing to the absence of the wall portion opposite the tearing zone, the lid itself no longer fits properly onto the underlying body, with the consequent drawback of possible spillage of the contents externally.

Drums are also known, which are manufactured with an internal layer of corrugated cardboard which is completely surrounded by or lined with a layer of smooth cardboard on which the images and trademarks of the product are printed.

In this case, the pre-cut tearing zone is formed only on the external layer of smooth cardboard and the internal layer is devoid of a covering so that, once opening has been performed, the internal layer also acts as a containment wall in the region of the torn zone.

Obviously this latter technique involves high costs and is in any case markedly superior compared to the manufacturing technique involving only a single cardboard retaining layer.

The object of of the present invention is that of providing a drum made of smooth cardboard or in any case consisting of a single layer and provided with an element designed to prevent spillage of the contents once opening has been performed.

Another object is that of increasing the rigidity of the drum in the zone of separation between body and lid thereof, after it has been opened.

These and other objects are all achieved by the drum for containing powdery materials, in particular washing powder, according to the present invention, characterized in that it comprises a wall-piece mounted so as to be partially integrally fastened to the internal surface of the walls of a drum in the region of a tearing zone pre-cut on at least three of the sides of the drum itself ; said fastening affecting only a bottom portion of the said mounted wall-piece, this portion, corresponding, below the said tearing zone, to the internal upper edge of a body of the drum.

This characteristic feature, along with others, will emerge more clearly from the following description of a preferred embodiment illustrated, purely by way of non-limiting example, in the accompanying illustrative plate, in which : - Figure 1 shows an axonometric view of the top part of a drum ; - Figure 2 shows, on a larger scale and sectioned perpendicularly, a side of the drum with the tearing zone ; - Figure 3 shows an axonometric view of a possible variation of embodiment of the top part of a drum.

A tearing zone 1, which is formed perimetrally and directly on at least three of the sides of a drum 2 and obtained by means of one or more pre-incisions I a in the thickness of the drum itself, forms a zone of separation between lid 3 and body 4 of the said drum.

A mounted wall-piece 5 is positioned inside the said three sides and just below the internal upper edge of the body 4, underneath the tearing zone 1, said wall-piece 5 being

integrally fastened thereto only by means of its bottom portion 5a.

A top part 5b of said mounted wall-piece is free, overlying the upper edge of the body 4, and its external surface is located flush with the internal surface both of the tearing zone I and of a portion of the internal bottom edge of the lid 3.

The steps for using the drum according to the present invention will now be described, referring to the reference numbers shown in the Figures.

Removing the tearing zone 1 by means of a suitable gripping element, not shown, the lid 3 and the body 4 of the drum 2 are separated from each other at least on three sides of the drum itself which is therefore open.

Even though the said lid and body, once the drum has been opened, do not fit perfectly together, the product contained inside the drum itself cannot fall out since the upper part 5b of the mounted wall-piece 5 acts as an internal frame covering the gap which is created as a result of tearing.

At the same time, this mounted wall-piece confers a certain degree of rigidity to the upper edge of the body 4 of the drum 2.

The fastening between bottom portion 5a of the mounted wall-piece 5 and internal upper edge of the body 4 of the drum 2 may be formed either by bonding or by seaming or by a stitching.

The mounted wall-piece may be made either of corrugated or smooth cardboard or plastic material.

In the example illustrated in Figure 1, the wall-piece 5 is mounted on three sides of the drum, but could be provided also on the fourth side as illustrated in Figure 3.

Obviously the shape of the drum may be as varied as possible, without thereby departing from the scope of the claims indicated below.