The present invention relates to an insulating plate element having a surface appearing as a building stone pattern, to which surface is fixed a number of tile or stone-l le shell members. Preferably it relates to insulating plates for outer use on buildings, where¬ by it is often desirable that after the said insulation the building appears with e.g. a brick-like face. In this connection the bricks are not carrying, i.e. it is sufficient to use a shell facing appearing like bricks and furthermore serving to protect the insulating element against the weather.

Consequently it will be sufficient to provide one of the surfaces of the insulating plate elements, which e.g. consists of mineral wool or expanded polystyrene, with a facing of rather thin shells for imitation of a building stone pattern, whereby the grooves between the shells may even be pointed before or especially after the mounting of the insulating element and the adjacent elements, and it is already known to provide the insulating elements with such shells by gluing of the shells onto the plate members, conf. US-PS 3,740,910. Furthermore it is known, conf. US-PS 3,645,715, to arrange the shells in the desired mutual configuration and then produce the insulating element by casting out the insulating plate material against or on the prelaid layer of shells. These known insu¬ lating elements, however, are rather expensive to produce, because the shells must be produced separately and then after a separate working operation be con- nected with the insulating plate member either by a

special gluing proces or by means of the said casting of the insulating material, whereby the production of the insulating plate element as a whole will be con¬ siderably more expensive than when already mass pro- duced, "clean" insulating plates can be used.

The purpose of the invention is to provide an insulating element of the mentioned type, which can be produced in a cheap manner from a mass produced "clean" insulating plate member without the required facing shells having to exist as pre-shaped and separately glued shell elements.

According to the invention the shell elements are produced in a castable material such as coloured fine concrete, which is fixed to the insulating plate member by being cast directly against or on this member.

Thus, according to the invention it is recognized that the shell elements do not need to be prefabricated elements, which in some special manner are to be connected with the insulating plate member, as this connection will appear as a direct result of the elements being made by casting against the permanent support, which, according to the invention, is re¬ presented by the insulating plate member. In this con- nection it should be mentioned that by the production of cast concrete products it is common practice to cast against a re-usable support member and that according to the invention such a support member is replaced by a vital part"of the very product being fabricated.

By the invention is obtained that the preceding difficult production of the facing shells and the following fixing of these to the mass produced in¬ sulating plate member are integrated such that by the casting of the "facing shell ^" substance" direct against the insulating plate member is obtained both

a shaping of the ϊacing shells with an acceptable stone-like appearance thereof and a fixing of the cast shell material to the insulating plate member already by the said casting, i.e. the shells will be both shaped and ifixed in a single working operation based on the use of a cheap, mass produced insulating plate member.- It nas proved possible to hereby in an easy manner, e.g.. by the use of coloured fine concrete, produce shell, elements appearing as natural tile or stone elements.

When the shell elements thus appear as directly cast elements it is, according to claim 2, rather easy to let them appear with joint edge surfaces, which are so inclined that at the lower edges of the joints they will generally be downwardly and outwardly inclined, whereby water as intruding into the joints will be easily drained therefrom. This shaping of the joint surfaces will be a simple question of a corre- ^' sponding shaping of the used casting mould, and this will, by the invention, in a completely natural manner be in accordance with the fact that the wall parts of the mould in a desirable manner are shaped with such an upwardly diverging cross section that the mould is easily releasable or easy to draw up from the cast substance.

According to claim 3 the invention furthermore comprises the method of producing the insulating plate elements in question. By this method it is decisive to make use of a..mould element covering the whole or a large part of the insulating plate member so that many or possibly all the shell elements on the said plate member may be cast in a single working operation.

For the disengagement of the used mould grating, according to general casting technique, it is expedient that the grating parts are made with slip, what will imply that the joints between the cast shell areas

will be of increasing thickness in the outward direction. This is, however, a useful advantage, since the lower surfaces of the joints will then be outwardly and down¬ wardly inclined by usual vertical mounting of the plate element, whereby the joints will be self-draining. For that reason it can be chosen to use a grating mould with a more pronounced slip than necessary for the very disengagement or release of the mould.

In the following the invention is described in more ^" detail with reference to the accompanying drawing, in which:-

Fig. 1 is a perspective view of an embodiment of an insulating plate element as manufactured according to the invention, Fig. 2 is a perspective view illustrating the method according to the invention, and

Fig. 3 is a sectional view of the mould grating as used with the method.

The prefabricated insulating plate element accord- ing to Fig. 1 consists of an insulating plate member 2- which on one side is provided with a layer of stone shells 4, e.g. in the brick pattern as shown. With dotted lines it is shown that the plate element may be made with opposite, staggered protrusions 6 and 8, whereby such plate elements can be juxtaposed with the use of a brick pattern with full bond. The same is obtainable by the use of regularly four-sided plate elements, if by large-scale production of the elements those shells are omitted which are to extend across the butt joints between the elements, and these shells are mounted manually after the setting up of the ele¬ ments. This in itself belongs to the known art, and it should just be emphasized that the above-mentioned special element shapes are also produceable according to the invention.

After the setting up of the elements, e.g. on the

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outer wall of a house, which is to be after-insulated, a manual pointing of the joints between the shells 4 is normally carried out; by the use of a usual joint mortar this pointing can hardly be made in connection with the production of the element, as this is not completely stabilized until it has been mounted at the mounting place.

As mentioned, the shells 4 according to the known art consist of prefabricated and carefully laid up shells, while according to the invention they are formed by simple casting directly on a standard in¬ sulating plate member 2. This casting may take place in different ways, but. preferably according to the illustrations of Pigs. 2 and 3: A standard insulating plate member 2 of e.g. mine¬ ral woll or expanded polystyrene is laid onto a vibro- table 10, and a mould grating.12 is placed on the plate member 2 fitting tightly along the outer edges of the plate member, where the mould grating may have a down- wardly projecting edge portion 14. The mould grating is pressed lightly against the plate member 2 and is locked to the vibrotable 10 by means of suitable lock fittings 16.

The mould grating 12, which generally has a thick- ness corresponding to the desired thickness of the shells 4, consists of a system of grating bars 18 corresponding to the joint pattern being desirable on the finished insulating plate element.

After the placing of the grating mould 12 on the plate member 2 a suitably coloured fine concrete sub¬ stance is poured over the grating mould, the substance by means of the vibrotable 10 being brought to complete¬ ly fill out the mould sections between the grating bars 18, principally just like casting of concrete members onto a temporary support table. The concrete substance may be treated from above by a thrust plate or a moved

smoothing disc, and attention is paid to the surplus concrete above the mould grating being scraped off the grating.

The exposed surface of the casting substance may be worked in any desirable manner for establishing a desired surface structure on the shells 4 thus fabri¬ cated, e.g. by being treated with a coarse broom.

Of course a casting substance must be used which . is well suited to be firmly fixed to the support in the form of the insulating plate member 2, but it has been found that a usual, fine concrete has an excellent binding power with most of the materials as.. ιsed for mass produced insulating plates. However, the binding ability, if desired, may be further increased by addition of a PVA-glue to the concrete substance.

When the casting substance has set shortly after the casting the grating mould 12 is removed from the workpiece by being lifted vertically off. Then the workpiese may be stored for hardening of the cast shells 4.

As already mentioned it is desirable that the mould bars 18 be shaped such that they produce a pro¬ nounced mould slip, as the joint cross section will hereby become especially advantageous with respect to the drainage of water from the joints in the mounted plate elements. It is clearly shown in Fig. 3 that the bars 18 distinctly show a decreasing thickness in the downward direction, and consequently the mould grating will be easy to lift off the cast layer of artificial stones 4 without particular slip problems.

It has proved advantageous that a net of steel or plastic is placed between the top side of the plate member 2 and the grating mould 12, as hereby a strength improvement of the finished plate element is obtained. It has been mentioned above that the casting of the casting material takes place directly against the

insulating plate member 2, but it will be understood that this may well be provided with a special surface layer, when. only this layer binds to the plate member 2 and is capable of receiving and binding the casting substance for producing the shells 4. As a special example the plate member 2 may be covered by a layer of asphalt paper or a similar steam stopping layer, which is able to hold the cast shells 4 and in this way make the produced elements usable for insulation of inner walls in buildings.

The main purpose of the invention is the production of the shell covered insulating plate elements with the use of a conventional concrete casting equipment, but the invention is not limited to this particularly advantageous and cheap production method, as the casting of the preferably shell-divided surface layer on the plates can be effected by means of other materials and other casting methods.

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