The invention relates to a container, especially a con¬ tainer suited for storing granular material, in which container there is a shell section, polygonal in cross section, and advantageously surrounding a bag made of plastic. The shell part is composed of liners and fluting cardboard placed between them. Additionally, the con¬ tainer includes a separate base section and a lid sec- tion.

When containers are used to store granular material, a bag made of plastic is placed inside them and the bag is then filled mechanically. One reason for using a plastic bag is to prevent pentane gas contained in the plastic raw material from escaping into the surrounding air dur¬ ing storage. Once the granular raw material is set in motion following the filling operation (e.g. when the lid is put in place or when the filled container is moved) , the plastic raw material becomes compacted in the con¬ tainer. When this happens the container lid should corre¬ spondingly come down but so that the lid would be con¬ stantly supported by the plastic raw material and not by the edges of the container-'s shell. Containers used for transportation and storage purposes are placed one on top of the other and consequently the lowermost containers carry the weight of those above them. As the edges of the shell section of a container cannot withstand such weight, the weight ought to focus via the container lid onto the granules of the plastic raw material and from them onto as large an area as possible of the internal surface of the container' shell.

In order for the above objects to be attained, it is ne- cessary for the container shell to be provided with a structure allowing the shell to be extended in height during the filling operation so that the shell can be filled to the brim. Similarly, it should be possible to

reduce the height of the shell to allow for compaction of the plastic raw material once the lid has been placed in position.

In prior art containers, the aforementioned problems have been solved, for example, by using a separate sleeve structure placed on top of the actual shell section. The shell section is provided with tiny catches that support the sleeve so that its top remains above the top of the shell section, thereby providing a brimming edge for the duration of the filling operation. Once such a container has been filled and the lid has been put in position, the pressure from above acting upon the lid will cause the catches supporting the sleeve to give way and the sleeve to slide down along the shell by the required amount.

In prior art solutions of the above kind the practice has been to use either two separate sleeve structures, with one at the top of the shell acting as the adjusting part and the other at the base of the shell acting as a rein¬ forcement for the shell. Use has also been made of single sleeve structures equal in height to the container shell. When sleeve structures are used, container shells are designed so that, together with their sleeve structures, they will be able to withstand the international drop test. In a drop test a full container is dropped from a height of 0.8 metres. A container's shell structures may become damaged but the contents of the container must not become discharged if the container is to pass the test.

The problem with the above kind of prior art solution is the need for the separate sleeve structure which natu¬ rally makes such a container cumbersome to use and manu¬ facture.

A container in accordance with the invention, however, is easy to manufacture and use. It is provided with a flex-

ible brimming edge made of a single liner and positioned at the top of the shell section. The said brimming edge makes it possible for the plastic bag placed inside the container for receiving the plastic raw material to be filled to the brim in excess of the actual height of the shell section. This in turn is essential in preventing the level of the granular plastic raw material in the container to fall below the level of the top edge of the container shell as this would cause the weight of an overlying container to focus on the edges of the shell of the underlying container. A container of this type is, of course, suited for the storage of all kinds of granular material.

The liner forming the outer surface of the shell section of the container in accordance with the invention is pre¬ ferably reinforced by webbing in order that even a fairly thin liner would be able to withstand the international drop test referred to in the above. The said web rein- forcement can, of course, be incorporated in any liner, and in several liners in fact, should the need arise.

The shell of a container in accordance with the invention is manufactured preferably from an attachment surplus and a section essentially rectangular in shape divided into partial sections of equal size by means of parallel creasings. The blank (i.e. the base material for the con¬ tainer) consists advantageously of an inner liner and an outer liner and, between them, two layers of fluting cardboard separated by a middle liner. The blank's outer liner, forming the inner liner of the shell of a finished container, is wider than the other layers in the blank. This being so, that part of the wider liner that extends above the other layers of the blank forms the container's flexible brimming edge. Fluting cardboard and cardboard are particularly suitable as blank material. Other corre¬ sponding materials may also be appropriate. When necessa-

ry, the number of liner and fluting cardboard layers im¬ plemented may exceed those mentioned in the above.

In the following, the invention is described by referring to one preferred form of implementation depicted in the appended figures, of which

Fig. 1 depicts a prior art container provided with two sleeve structures,

Fig. 2 depicts a prior art container provided with one sleeve structure,

Fig. 3 depicts a container in accordance with the in- vention, and

Fig. 4 depicts a blank used in the construction of a container in accordance with the invention.

The prior art container shown in fig. 1 consists of two external sleeve structures (2 , 3) of the octagonal shell (1) . The upper sleeve structure (2) is shown in the posi¬ tion that it assumes when supported .by the protrusions (4, 5) in the shell (1). Figure l also shows the con- tainer's octagonal base section (6) that fits inside the container's shell (1) . The container's octagonal lid sec¬ tion (7) fits around the outside of the upper sleeve structure (2) . When the lid (7) is placed in position and pressed down, it in turn forces the upper sleeve struc- ture (2) down because the protrusions (4, 5) have been so formed as to give way. The plastic bag inside the con¬ tainer is indicated by the numeral 9.

The prior art container shown in figure 2 corresponds to the container shown in figure 1 except for the one only sleeve structure (2) , essentially equal in height to the shell (1) , used in connection with the container shown in

figure 2 .

In the container in accordance with the invention, as shown in figure 3, there is a flexible brimming edge (8) formed on the upper edge of the container shell (1) , the said brimming edge superseding the sleeve structures. Additionally, the outermost liner in the finished con¬ tainer according to the invention is net-reinforced in order to have the container pass the international drop test. Here too, the container's octagonal base (6) fits inside the container's shell (1) and the octagonal lid (7) is guided into the container's shell section (1) . Since the brimming edge (8) is formed of a simple liner, its rigidity is sufficient to support it during the fill- ing up of the plastic bag (9) inserted into the con¬ tainer. However, when the lid (7) is placed in position over the container, the brimming edge (8) crumples easily under the lid when a load is imposed upon the lid (7) .

The container in accordance with the invention is formed preferably of the blank shown in figure 4, the said blank being essentially rectangular in shape and in it the liner acting as the outside liner at this stage is wider than the other cardboard layers. In the container shell formed by folding, this wider outside liner becomes the shell's inside liner and provides the container with the flexible brimming edge (8) . Parallel creasing is employed in dividing the blank suitably into the attachment sec¬ tion (11) and eight sections (10) of equal width. The said attachment section is used to connect the blank's ends to one another. The most appropriate means of attaching the ends is by using glue and staples. It is thus possible to keep the container shell folded flat during transportation and storage so as to use less room. When this is done, the shell is folded out into its oc¬ tagonal shape just prior to the filling stage at which stage its base section (6) and the plastic bag (9) are

put in their positions.

The invention also includes a container circular in cross section. During transportation this type of container can be kept stacked with the end seam glued and pressed flat along two opposite folding creases. Alternatively, the gluing of the container seam can be carried out at the filling stage at which stage the blanks can be trans¬ ported fully open in stacks, thereby avoiding the struc- tural weakenings to the shell caused by the creasings.