The present invention relates to a building element which is disclosed in the preamble portion of the appended claim 1.

Light walls, for instance partitions, have been heretofore built generally of bricks by masonry or of gypsum boards. When the partition is made of brickwork, it becomes heavy, and the work requires a skilled person (mason). When the wall is made of gypsum board, the work requires the professional skills of a carpenter. The above-mentioned building materials are in addition heavy to transport and the methods are dusty and mess up places at the building stage. Additionally, when these constructions are demounted, the material can no longer be utilized, but they end up as waste to dumping grounds.

Through Swiss patent publication 613486 and British patent publication 1157682 are known building elements made of plastic by moulding, sorts of plastic bricks, which can be built to form light walls, such as partitions, by placing them on top of each other. The plastic bricks can be placed on top of each other by means of locking recessions and projections located on their upper and lower edges. Further, cavities extend vertically through the bricks and these are formed between the transverse support ribs, in other words between the connecting parts which interconnect the upright outer surfaces of the bricks. The cavities can be used for placing various parts, such as cables, within the wall.

Because the elements are manufactured as one piece by moulding in a mould, the manufacturing technique used limits their design. On the other hand, moulding in a mould is the only economically profitable manufacturing method for light plastic elements. The forming of support ribs requires much of the mould design, because the drafts necessary for the releasing of the moulded piece and other things must be taken into account. This restricts the use possibilities of the plastic element which in other respects is practical in building of light non-bearing walls.

The purpose of the invention is to present a building element of a new type without limitations set by the previous technique. For achieving this

purpose, the building element according to the invention is mainly char¬ acterized by what is disclosed in the characterizing portion of the ap¬ pended claim 1. The building element is formed of two halves, which can be connected together to obtain elements without limitations to their interior structure by moulding technique. Each half has an even surface forming the outer face of the element and in its inner side it has the parts forming the interior structure of the element. By inter¬ connecting the element halves the outer faces remain outermost and the said interior parts form the desired interior structure when joined together. In this way very practical constructions can be accomplished, which would be impossible by usual plastic moulding technique or which would require at least complicated mould technology for their realization.

As far as other advantageous embodiments of the invention are con¬ cerned, reference is made to the appended dependent claims 2 — 10 and the following description.

The invention is described in the following more closely with reference to the accompanying drawings, wherein

Figs. 1a-e show a first half of the element,

Figs 2a-e show a second half of the element,

Figs. 3a-b show the halves and elements interconnected from below and at the front, and

Fig. 4 shows in vertical section the elements joined one on top of the other and end-to-end.

Figs. 1a-e show the first half A of an element from below (Fig. 1a), at the side (Fig. 1 b), from above (Fig. 1c), at the end (Fig. 1d) and in verti¬ cal section (Fig. 1e). The half has an even outer face 1a, which forms the wall surface of a finished construction. From a back face which is located on the other side of the outer face 1a and forms the inner face of a hollow element, there project connecting parts 2a along the edges of the half. In the case shown by Figs. 1a-e the connecting parts 2a are

located at the upper and lower edge of a wall of uniform thickness formed by the outer face 1a and the inner face, and the extreme parts are located at corners formed by the upper and lower edges and the side edges. These connecting parts 2a have the shape of L as seen in a direction perpendicular to the main plane of the element half (plane of the outer face 1a), the parts being shaped in such a way that one of the legs extends in the direction of the upper or lower edge of the half and the other one is directed perpendicularly therefrom to the middle. In the case shown by the Figures the half A has one connecting part 2a, which is angle-shaped in the above manner, in each corner of the half, and additionally other connecting parts 2a between them along the upper and lower edges of the element.

As best shown by Fig. 1b, the free ends of the connecting parts 2a have recessions 6a extending in their direction and located in the connecting part 2a on the outer edge side. Their purpose will become evident when the other half B depicted by Figs. 2a-e is inspected, which half is shown from below (Fig. 2a), at the side (Fig. 2b), from above (Fig. 2c), at the end (Fig. 2d) and in vertical section (Fig. 2e). The construction of this half B is in other respects similar to that of the first half A and it is symmetrical in a mirror-like fashion with the first half A, the difference being that in this other half B the connecting parts 2b which have similar shapes and are located at the same points, have tongues 6b, which are positioned parallelly to the longitudinal directions of the afore- mentioned recessions 6a, and the recessions 6a and the tongues 6b are situated at the same points in the main planes of the element halves A, B.

When the element halves A and B are placed against each other in such a way that the connecting parts 2a and 2b point towards each other, the tongues 6b in the connecting parts 2b of the second half B will be received by the recessions 6a of the connecting parts 2a of the first half A. Figs. 1a-c and 2a-c show also a hole 8a located in the above-mentioned overlapping parts of the connecting parts 2a, 2b, de- signed to receive a barb-shaped projection 8b formed in the tongue 6b of the second half B. In this way the connecting parts can be locked to each other by means of snap-in locking on their free ends.

The upper edge of each element half A, B, that is, one of the longitudi¬ nal edges, have also hooks 4a, 4b directed away from the half in the di¬ rection of each main plane and situated slightly inwardly of the outer face 1a or 1b of the respective half. The purpose of these hooks will be described hereinafter.

Fig. 3a shows the above-described element halves A, B in the intercon¬ nected state. The element halves form a finished element 1 , the outer faces 1a, 1b of which are constituted of the outer faces of the above- mentioned halves A, B. Correspondingly, the connecting parts 2a, 2b joined together at their ends constitute the connecting parts serving as the support ribs between the above-mentioned outer faces and forming at the same time the interior structure of the hollow element 1.

Fig. 3a reveals also, how two elements 1 can be joined together in abutment. One of the end edges of each element half A, B, that is, a vertical edge, has an end flange extending from the outer face 1a, 1b towards the middle part, having a strip 9a, 9b extending outwards from the element half end at the end of the flange. In the assembled position of the element 1 these strips 9a, 9b point outwards from the end and are accommodated in an opening at the opposite end of another assembled element 1. This opening is formed between end flanges 10a, 10b extending inwards at the end edges of the halves A, B in alignment with the strips. Each element half A, B has a vertical strip 9a, 9b respectively in the first end and in the opposite end there is a vertical end flange 10a, 10b respectively, against the edge of which the corresponding strip 9a, 9b of the next element 1 can be guided.

Fig. 3b shows also, how two elements can be placed one on top of the other. The hooks 4a, 4b directed upwards in the lower element 1 are received on locking shoulders 5a, 5b, which extend from the inner sur¬ face of each respective element half 1a, 1b towards the middle part of the element at such a distance from the inwardly extending edge flange 13a, 13b at the lower edge of the element half A or B that corresponds to the distance of the barb of the hook 4a, 4b in the direction of the main plane of the element half A, B from an inwardly extending edge flange 12a, 12b, from which the hook 4a, 4b projects upwards and which is situated along the upper edge of the lower element half A, B.

The inwardly turned edge flanges situated along the longitudinal edges of the upper and lower element 1 rest one on top of the other when the elements are locked, and the hooks are locked between the locking shoulders 5a, 5b by snap-in locking in such a fashion that the barbs will be placed behind the inner edges of the shoulders 5a, 5b. Also such a locking arrangement is possible that the hooks 4a, 4b extend downwards from the lower edges of the element halves A, B, and the locking shoulders 5a, 5b are situated correspondingly on the upper edges of the element halves A, B. In each case the members co- operating in the snap-in locking are situated on the horizontal longitudi¬ nal edges of the outer faces 1a, 1b of the halves A, B, which edges serve for superposing the elementsl .

As it has been shown by the Figures, the element halves A, B and the elements 1 have a rectangular shape as seen in the plane of the wall, having dimensions that correspond mainly to an ordinary brick. Thus, in the elements 1 and element halves A, B the horizontal longitudinal edges are longer than the vertical end edges. The elements 1 can be piled one on top of each other and end-to-end like ordinary bricks in such a fashion that the upright seams in superposed rows are always out of alignment, whereby elements of differing lengths can exists for ending the wall, or like shown by Fig. 4 where only the first element halves A are presented, the elements are aligned in vertical direction. Especially it can be seen in Figs. 1a-e and 2a-e that the superposed longitudinal edges of the element halves A, B have strips 11a, 11b in one of the longitudinal edges, lying between the hooks 4a, 4b and being inserted behind the edge flanges 13a, 13b located in the other longitudinal edge. In this way the forming of transverse seams ex¬ tending straight through the wall is avoided, which would result in weakening of the sound insulation. The strips 9a, 9b situated at the edges of the element halves and overlapping the vertical seems have the same importance.

The elements can be cut to shorter elements along the broken lines shown in Figs. 1 b and 2b. On the inner surface of the element at the cutting point is formed a protruding flange 14a, 14b, having a construction that resembles that of the end flange 10a, 10b and joining on both opposite ends to the edge flanges 12a, 13a, respectively 12b,

13b extending on the longitudinal edges of the respective element half A, B. The cutting can be performed by means of a saw either when the halves A, B are separated or after the element has been assembled. For guiding the cutting tool the edge flanges 12a, 13a and 12b, 13b respectively are provided with notches 15a, 15b aligned with the coming outer face of the flange 14a, 14b. Elements can have also other shaping for marking the cutting line, and a shaped part of this kind can most preferably be utilized in guiding a cutting tool. It is apparent from Figs. 1a-c and 2a-c that an element comprising eight connecting parts, that is four pairs of connecting parts, can be cut to 2/3 parts or 1/3 parts of its original length, to an element comprising three or two pairs of connecting parts, respectively. It is therefore advantageous to have at least two cutting lines in the element that are marked in a suitable way and behind which, as seen in the same direction, is located immediately an edge structure corresponding to the end edge of a whole element as well as connecting parts 2a, 2b at the corners formed by the end edge and the upper and lower edges of the sub-element so separated.

Fig. 3a illustrates also, how cavities 3 passing through the element 1 in a vertical direction are formed between the connecting parts constituted of the pairs of connecting parts 2a, 2b situated along the longitudinal di¬ rection of the element halves A, B at spaced relationship. Correspond¬ ingly, Fig. 3b reveals, how a cavity 7 passing through the whole ele- ment 1 in its longitudinal direction is formed between the connecting parts 2a, 2b placed in abutment in upper and lower edges of the element halves A, B. This cavity extends perpendicularly to the above- mentioned upright cavities 3. This cavity 7 makes it possible to design the interior of the light wall to be built in a more versatile fashion, and, for example, it is possible to lead through various structures always in a desired direction.

The construction is, however, not limited only to such elements having pairs formed of only two vertically spaced connecting parts 2a, 2b, but it can also have connecting parts between these upper and lower edge connecting parts.

The element according to the invention is easy to manufacture for example by injection moulding technique from a suitable thermoplastic. In the practice, two moulds having structures corresponding to the ele¬ ment halves A and B are needed. The joining can take place right after the manufacture of the pieces by placing the halves against each other. The attachment of the halves together can be performed easily by snap-in locking through the connecting parts 2a, 2b.

The invention is suitable for building all light walls, and one of its advantages is still that the wall is easy to demount for bringing the building materials back to use. Moreover, the wall has already a tidy surface, compared with a brick wall, and separate surface finishing stages are not necessarily needed. The outer faces 1a, 1b can be already provided with a suitable colour surface or decoration. However, this does not exclude the surface finishing of a built wall in some tra¬ ditional manner, for instance by using wallpaper. The fixing of pictures and other wall decorations is easy owing to the employed plastic material. The wall can be used also as a wall for moist spaces and in this case it does not require special vapour barriers or covering with tiles.