WO2018012988A1

WO2018012988A1 - A construction set for covering a substrate, in particular a floor substrate

Info

Publication number: WO2018012988A1
Application number: PCT/PL2017/000068
Authority: WO
Inventors: Adam Chojnowski; Piotr Paweł CHOJNOWSKI
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-07-13
Filing date: 2017-07-07
Publication date: 2018-01-18
Anticipated expiration: 2019-01-13
Also published as: EP3485106A1; PL417949A1

Abstract

The invention refers to a construction set for covering a substrate, in particular floor substrate, comprising plate elements for covering the substrate and connecting elements for joining together the adjacent plate elements, while maintaining a fixed distance between them to form a dilatation gap, characterized in that the connecting elements (2) comprise at least two, located on a base (3), assembly protrusions (4) seated in the adjacent connected plate elements (1) equipped on their substrate side, along at least two opposing side edges, on at least part of their length, in equal distance therefrom, with assembly ducts (7) of similar a cross-section, with the connecting elements (2) joining the adjacent plate elements (1) seated therein, by means of the assembly protrusions (4), wherein when the plate elements (1 ) are provided only with assembly ducts (7) parallel to each other and located only along two opposing side edges of plate elements, then these elements optionally comprise also the assembly holes (8) located by the edges without the assembly ducts (7), in which holes (8), at least some of them, assembly protrusions (4) of the connecting elements are seated.

Description

A construction set for covering a substrate, in particular a floor substrate

The invention refers to a construction set for covering a substrate, in particular a floor substrate, e.g. terrace floors, garden sheds, parts of gardens, bathing premises, or recreational elements at edges of swimming pools or other water containers. The construction set, upon some adapting, can also be used for other purposes e.g. for elevation finishing, inclined or vertical surfaces.

There are known floor systems assembled from repeatable elements, in particular terrace floors made of wooden elements or of modified plastics, which require to be dimensioned and cut depending on the floor size, and their montage is difficult and usually time-consuming.

European patent application EP2740858A1 (also Polish application

P.401893) discloses a construction set for covering a substrate comprising plate elements, especially boards assembled with connectors built from the base and convex protrusions projections mounted thereon. Plate elements are provided with assembly sections with concave holes with adjusting sizes and shapes of assembly protrusions of the connectors. A do-it-yourself assembly modular set is obtained, not requiring dimensioning or any special fastening, e.g. mounting of individual components with srews. Subscribed solution is suitable for wooden or wood-based and wooden-like coatings, where the degree of violation of their solid structure is minimized to reduce the areas that are exposed to destructive external conditions such as moisture. Therefore, in the described solution, relatively small assembly holes are used almost entirely blocked by the assembly protrusions of the connectors.

At present, there is still a need to develop new, more universal technologies for more diverse flooring materials, i.e. materials containing, e.g. plastics, resins, etc, which can be produced by moulding, pressing or extrusion.

Such materials defined as imitations of wood are known, for example, from international patent application WO2011 100995A1 . Due to the presence of materials such as PVC in the disc'osed compositions, moulded articles of any shape are manufactured by various known methods e.g. by heat treatment. In addition to plastics, products of this type, include fillers of plant origin such as rice, maize, bamboo or wood waste, and mineral fillers, e.g. derived from crushed rock materials.

A construction set for covering a substrate, in particular floor substrate, comprising plate elements for covering the substrate and connecting elements for joining together the adjacent plate elements, while maintaining a fixed distance between them to form a dilatation gap, according to the invention is characterized in that, the connecting elements comprise at least two, located on a base, assembly protrusions seated in the adjacent connected plate elements equipped on their substrate side, along at least two opposing side edges, on at least part of their length, in equal distance therefrom, with assembly ducts of identical a cross- section, with the connecting elements joining the adjacent plate elements seated therein, by means of the assembly protrusions, wherein when the plate elements are provided only with assembly ducts parallel to each other and located only along two opposing side edges of plate elements, then these elements optionally comprise also the assembly holes located by the edges without the assembly ducts, in which holes, at least some of them, assembly protrusions of the connecting elements also are seated.

Preferably, the plate elements are cuboidal, having the identical thickness, and assembly ducts are guided through the perpendicular edges of the plate elements or do not reach these edges.

Preferably, assembly ducts in the plate elements are located along all edges of these elements, at least part of their length.

Preferably, the plate elements comprise more than two mutually parallel assembly ducts, preferably three, four, five or six.

Preferably, the plate elements may be solid or ribbed and/or contain recesses or internal chambers or ribs reducing the weight of these elements, optionally such recesses may have a cross section and a mould the same as the assembly ducts.

Preferably, when the set consists of the plate elements of various sizes then optionally, the length and/or width of the plate elements is interdependent and depends on the width of the set dilatation gap so that it is a multiple of the smallest width or ienyth of the plate element increased by the sum of the widths of the dilatation gaps corresponding to that multiple.

Preferably, connecting elements are equipped with at least two assembly protrusions, located on the base.

Preferably, connecting elements are equipped with at least one through assembly hole, located on the base.

Preferably, connecting elements are equipped with adjustment protrusions positioning a dilatation gap between the plate elements, wherein the adjustment protrusions optionally comprise additional convex profiles connecting the side wa!is of the plate elements.

A set of the invention is designed for fast and simp!e, optionally repeatabie, self-assembly and self-disassembly, which is carried out manually (without tools) i.e. it does not require any special operations, like dimensioning of construction elements, cutting them, designating and drilling assembly holes in plate elements. The set consists of identical, uniformly shaped and uniformly sized connectors that connect adjacent piate elements that may also be identical or have different sizes but in any case are provided on their substrate side with at least two assembly ducts, arranged along the edges of the piate elements, located at equal distance from the edges of the piate elements. The assembly ducts are sized to press fit the assembly projections placed on the base of the connecting elements. Providing joints based on longitudinal assembly ducts allows the plate elements to be joined at any desired location over their length, providing the possibility of covering a complex substrate, such as an oblique or rounded substrate.

This technology is dedicated especially to plate elements based of plastic, such as PVC, and partly of natural origin, such as rubber and other binders or resins. These materials allow to achieve different forms of plate elements. In relation to natural wood, this type of raw material has a higher strength and hence plate elements do not have to be solid as homogeneous solids throughout in full volume, but may be lighter, with hollow spaces inside. The modular set as described, makes it possible to assemble the floor in a so-called floating system (the floor freely covering the substrate, i.e. it is by no means joined to the substrate). Optionally, the connecting elements may optionally be provided with assembly holes which allow the attachment of some of the connectors to the substrate, e.g. to the joists of the floors or terrace floors.

The subject of the invention is shown in an embodiment on a drawing, on which fig. 1 presents e.g. a cuboida! plate element of the set as seen from the substrate side with two parallel assembly ducts shown along the two opposite edges of the plate element over the entire length, fig 2 presents a plate element with three identical, parallel assembly ducts (two edge ducts and one central), fig. 3 presents a plate element with five identical, parallel assembly ducts, fig. 4 presents a plate element with assembly ducts arranged in five lines, divided into sections, fig. 5 presents a ribbed plate element, wherein on the side edges side the rib forms two parallel identical assembly ducts, fig. 6 presents a plate element with two assembly ducts and with assembly holes on the edges without assembly ducts and with three internal chambers reducing the weight of the plate element, fig. 7 presents a plate element with two assembly ducts, as in fig. 1 , but this element is additionally provided with grooves on the side walls of the plate elements, fig. 8A presents a connecting element comprising an oval base and two circular assembly protrusions, fig. 8B presents an analogous connecting element to fig. 8A, but it is additionally equipped with two adjustment protrusions and with an assembly hole, fig. 8C presents a connecting element with an asymmetrical arrangement of rectangular assembly protrusions, varying with the height of the protrusions, fig. 8D presents a connecting element with two symmetrical assembly protrusions with a cross section of elongated rectangles, and fig. 8E a similar connecting element but the side walls of assembly ducts are profiled, fig. 8F presents a connecting element provided with four circular assembly protrusions, symmetrically placed on the base, fig. 8G presents connecting elements provided with assembly ducts divided into two adjacent parts, fig. 8H presents a. connecting element with four assembly protrusions and with a non-slip texture on the side of the substrate, fig. 8J presents a top view of a connecting element of fig. 8H, fig. 8K presents a connecting element with four assembly protrusions placed in pairs one by one, to be placed in four parallel ducts, two per adjacent plate elements, fig. 9 presents a connecting element with two assembly protrusions with profiled side walls, provided with adjustment protrusions and a through assembly hole, fig. 10 presents a connecting element with two assembly protrusions and with a longitudinal adjustment protrusion provided with lateral convex profiles, fig. 1 1 is a cross-sectional view of a combination of two plate elements comprising two assembly ducts ^"joined by connecting elements in the variant of fig. 8A, fig. 12A is a diagonal view from the side of the substrate of a combination of four piate elements provided with four assembly ducts, the elements being placed in different directions, i.e. one placed on the front of the other three, and the connecting elements of fig. 8J were used to connecting plate element, fig. 12B presents a combination of fig. 2A from the substrate side, fig. 13 presents a combination of four plate elements of fig. 6, in analogue setting as shown in fig. 12A, however, different connectors were used in the combination, and the connection was achieved by assembly ducts and assembly holes present in plate elements, fig. 14 presents in a view from the substrate side a combination of four plate elements of fig. 2 having assembly ducts on the edges and in the central part, fig. 15 presents in a view on the side of the substrate a combination of connected four plate elements having assembly ducts located along all four edges, fig. 16 presents elements of the set mounted on the carrier joists using the connectors of fig. 8B. Connecting elements in figures 8A, B, C, D, E, F, G, H, J, K and fig. 9 and fig. 10 are shown in enlarged wiev.

A set of the invention comprises piate elements 1 , for example in the shape of a cuboid or comprising cuboid top usable layers and preferably identical connecting elements (connectors) 2 comprising a base 3 with perpendicular or slightly tilted in relation to this base, convex, protruding beyond the base level, assembly protrusions 4 supported thereon. Additionally, adjustment protrusions 5, protruding beyond the base 3 may optionally be mounted, for example one or two per each base 3, the protrusions being able to have laterally located, convex profile 6, located on both sides of the piotrusion 5, wherein the convex profiles are directed towards the assembly ducts 4. Connecting elements 2 have a base optionally provided on the side of the substrate with anti-skid texture 9 in the form of notches or incisions or serrations, and the assembly protrusions 4 may be possibly provided with upper curvature in the form of a head 10 located in the furthest part of the base 3 and having an enlarged cross-sectional area relative to the lower part of the protrusion 4. The said widened head 10 can only partially cover the protrusion 4. The base 3 optionally comprises a through assembly hole 14, preferably located in the central part of this base 3, between the assembly protrusions 4.

The plate elements 1 are provided on the side of the substrate with assembly ducts (recesses) 7 located along the edges (parallel to these edges) of the plate elements 1 , the ducts beiny located at least along two edges of the plate element 1 , preferably longer edges, at least on the part of the length of such edges, preferably occupying at least 20% of the length of these edges or 30% or at least half of the length of such edges, and more preferably 60 to 100% of the length of such edges, e.g 60 or 75% or 80% or 90% or 95% or 100% of the length of the plate elements.

Plate elements 1 are optionally also provided with assembly holes 8 located on the side of the plate element edge, which is not provided with an assembly ducts, preferably it is a shorter plate element edge. The holes 8 are not through, i.e. they are not visible from the usable side and allow mounting the assembly projections 4 therein. Elements 1 may optionally not be made of solid material and may have a form of lighter structure provided by internal longitudinal recesses 11 , open on the side of the substrate or longitudinal chambers 12 closed on the side of the substrate or ribs 13 in the form of transverse walls with respect to the usable surface of tho plate element. Recesses 11 , chambers 12 and ribs 13 are preferably guided parallel to the longer edges of the plate elements and may be closed from the shorter lateral edges. In this way an aesthetic effect imitating a solid plate is created.

The plate elements 1 , apart from the ducts 7 located on the side of the substrate, may be additionally provided with lateral grooves 15 that may be used for additional lateral joining or stabilising individual plate elements 1 , by means of adjustment protrusions 5 located on both sides, profiles 6 protruding towards the grooves 15. The profiles 6 is to press fit the grooves 15. The grooves 15 are located parallel to the ducts 7, however in the planes perpendicular to each other, i.e. the grooves are recesses arranged on the plate elements on their planes perpendicular to the planes in which the assembly ducts are located.

The term "plate elements" for the purposes of the present invention is to be understood broadly as products in plate form at least on the usable side (i.e, the upper side, accessible to the user), in the simplest form, they can be wooden boards or elements made from wood or wood-based materials, such as plastic blends with natural fillers such as wood dust, cellulose fibres, bamboo etc. or entirely made of plastic, preferably imitating wood. All these raw materials should meet the requirements for articles subject to weather conditions.

Plate elements can be solid (without cavities/chambers inside) or may contain such cavities inside. The only limitation is the necessity to make sufficiently durable assembly ducts and optionally assembly holes to ensure stable fastening of the connecting elements. Assembly ducts may be hollow in the solid pattern of the plate element as longitudinal recesses - "grooves" (e.g. fig. 1 and fig. 2) or may be formed by transverse - with respect to the usable surface - baffles, ribs arranged on the side of the substrate, which allows for a lightweight construction (shown in fig. 5). In this embodiment, assembly ducts are located along the two edges of the plate element, on both sides thereof, limited by ribs, mounting ducts, and the remaining cavities are the mass-reducing chambers. These chambers, however, can also be used as additional assembly ducts and, for example, two assembly ducts can be provided along each edge of the plate element. Ribbed plate elements (other than assembly ducts) may also have other forms such as a truss. The ribs may have a shape of various broken lines (for example, mapping the letters T, Z, N, U, etc.).

The plate elements may comprise internal cavities or cavities or chambers of any shape and size (as in fig. 4, fig. 5 and fig. 6). These structures are not the subject of the invention, but are often intended to reduce the weight of the article. Apart from the need of providing the assembly ducts the design of the plate elements can be arbitrary.

The assembly ducts may be located along ail edges of the plate element (as on joined plate elements in fig. 5). The ducts do not have to extend over the entire length of the plate elements, but can be interrupted, present only along the part of the edge of the plate element (as in fig. 4). It is possible that assembly ducts run "through" - i.e. cutting edges of the plate element perpendicular thereto (as in fig. 1 , fig. 2 and fig. 3) but in the other embodiment the ducts do not reach the edges of the plate elements (as in fig. 4), which may be more preferable because then the ducts are not visible for the user.

The set of the invention comprises known connecting elements (connectors) having a base with the floor elements fixed thereon, and which isolates these elements from the substrate having the role of amortization and stabilization. The set may use known connectors presented in the application EP2740858A1 , but the person skilled in the art it is clear that many other, alternative, technically equivalent connectors may be designed. They may have e.g. a round, oval, polygonal, square, etc. base The assembly projections may be cylindrical (fig. 8A) or close to elongated cuboids (fig. 8D), may have a circular, polygonal, square and other cross section. The surface of the assembly protrusions may be corrugated or ribbed, which enhances the strength of the resulting joint. Preferably, the connecting element is symmetrical such that the position of the assembly protrusions is identical to the centre of the base, but it is also possible to use asymmetric connectors as illustrated in fig. 8C. It is important that the assembly protrusions are on the base at a distance adjusted to the assembly duct setting. The assembly protrusions of the connectors may be moved along the assembly ducts with the resistance to ensure a tight coupling of the set elements. When the assembly protrusions are e.g. square or circular, their width or diameter, respectively, is determined by the width of the assembly duct. However, when the assembly protrusions are elongated (the length is greater than the width), such as in fig. 8E, then only their width is imposed by the width of the assembly duct, and the length of the protrusions can be arbitrary. The length of the assembly ducts may ensure the movement of the connectors along the ducts, so the ducts may have a length that is at least twice the length of the assembly protrusions.

The connecting element in the set according to the invention is a repeatable element, fixed on the plate element sections and which is slid into adjacent plate elements spaced apart by a fixed distance - dilatation gap. The connectors are designed such that when fastening two adjacent plate elements, each of them is assigned to the same part of the connector. The connectors located on the substrate during assembly and rotated 180° to the vertical axis passing through the centre of their base will thus provide the same fastening the plate elements, which is convenient for the user (it is not necessary to search for the one specific correct connector setting). The durability of joining the connecting elements to the plate elements is ensured by adjusting the size and shape of the assembly protrusions of the connectors to the shape of the assembly ducts in the plate elements. At the same time, the edges of the ducts are supported on the bases of the connectors, which creates the same size support for the entire structure. Due to providing the connector with the base of a certain constant thickness, the assembly protrusions are fixed at a predetermined distance from the substrate, which causes the plate elements to be suspended at a certain height from the substrate, while maintaining the ventilation space.

The assembly ducts have a cross-section of the width of the assembly protrusions. In this way, the assembly protrusions cooperate with the assembly ducts to ensure that the entire floor covering system is joined. In turn, the distances between the assembly ducts are determined by the distance between the assembly protrusions on the connector. The assembly protrusions on the connectors are preferably identical or symmetrical e.g. may be inclined towards each other. The assembly ducts assigned to join one and the same connector are respectively identical or symmetrical i.e. they have a symmetrical cross section with respect to the central axis of the plate element parallel to the sides along which the assembly ducts run. The term "ducts with identical cross-section" for the purposes of the present invention covers both of the above cases. The assembly protrusions may have the same shape over the entire height, but they can also be variable with the height, providing closer fitting of the assembly protrusions in the interior of the assembly ducts in some areas.

In the simplest embodimen^t of the invention, the connecting element comprises two opposing assembly protrusions fixed on the base (e.g. the connector shown in figs. 8A, 8D, 8E). Then the connecting element comprises two assembly ducts, guided parallel to the longer edges of the plate elements (as shown in fig. 1 ) and the connector joins adjacent plate elements, i.e. one connector protrusion is in one plate element and the other in the adjacent plate element. Thus, a connection shown schematically in sectional view in fig. 11 is achieved. The connector used may be provided with adjustment protrusions (as shown in fig. 8B).

In another embodiment, the connector may comprise assembly protrusions which consist of several parts mounted together at the base of e.g. two parts as shown in fig. 8G. During assembly, parts 4a and 4b (fig. 8G) are pressed together to facilitate the pressing of the entire assembly protrusion into the assembly duct. The effect of resilient pressure exerted during assembly can increase the effectiveness of the connection. The outer shape of such assembly protrusions divided into parts is the same as the usual above-mentioned assembly protrusions - they are adapted to the internal shape of the space of the assembly ducts.

The connecting element may be optionally provided in the central part of the base (e.g. between the assembly protrusions) with at least one through assembly hole, as shown in fig. 9, designed to fasten the connectors, and thus the whole set to the substrate, e.g. to the joists of the terraces or used alternatively e.g. on damaged or non-levelled substrates. This embodiment of the invention is shown in fig. 16, where the lower part shows the joists, and above them the connecting elements with the screws (shown in fig. 8B) and plate elements of the set in the upper part. These mentioned through assembly holes may also be placed in a layout of two per the base of the connector, e.g. on two opposite ends of the connector. In another embodiment of the invention, plate elements with two assembly ducts (as well as with internal chambers) can additionally be provided with assembly holes at the duct-free edges as shown in fig. 6, which makes it possible to join plate elements on all edges. As shown in Fig. 13, three longitudinally set plate elements V are joined with a plate element 1 " aligned transversely thereto through the three connecting elements 2', which are mounted in the assembly duct of the transverse plate element 1" and also in the assembly holes of three longitudinal plate elements 1'. In such an embodiment, a modular set is made, i.e. composed of plate elements arranged in different directions, different configurations, and mutually compatible (system of blocks). Then the length of the plate elements is a function of their width taking into account the correction associated with the dilatation spaces, i.e. the length of the transverse plate element 1" is the sum of the widths of the elongated elements 1' and the sum of all dilatation spaces between the summed widths of the longitudinal elements V . An analogous modular set may be made of plate elements of different sizes {e.g, square and rectangular, or plate elements of equal width but different lengths). The necessary condition for achieving this effect is a common shape and size of the assembly ducts, same for all plate elements, and their distance from the edges of the plate elements, and the size of the assembly holes adjusted to the size of the ducts so as to be able to use connectors with identical assembly protrusions. A similar modular system is described in EP2740858A1 and it will be clear to the person skilled in the art that plate elements are predictable.

A similar principle of the modular set can be achieved by providing the plate elements with the assembly ducts not only along their edges (edge ducts) but also along their central axis, the longitudinal axis parallel to the edge ducts - such a plate element is shown in fig. 2 and fig. 3. Such central ducts can be connected to the edge ducts, e.g. by the connectors of fig. 8A (additionally provided with the assembly protrusions) by placing the plate elements mutually perpendicular, as shown in fig. 14.

Another embodiment (shown in figs. 12A and 12B) discloses another option of the modular set by providing piate elements with edge assembly ducts and two central assembly ducts. In this case, connectors are provided with four assembly protrusions, symmetrically aligned with two on each edge of the base, as shown, for example, in figs. 8F and 8J. In such embodiment of the invention two assembly protrusions are placed on in the edge ducts of adjacent parallel plate elements. However, when joining mutually perpendicular plate elements, two assembly protrusions of one connector are placed side by side in the same edge ducts of the first plate element, and the other opposing two protrusions of the connector are placed in two central ducts of the second plate element (one protrusion in each of two ducts), perpendicular to the first one (figs. 12A and 12B). The assembly protrusions in the connectors may be spaced on the base at the same distances (on a square plan), and then the distance between the edge ducts of the adjacent parallel elements along with the width of the dilatation gap between them is equal to the distance between the two central assembly ducts. If the assembly ducts on the base of the connector are not positioned on a square plan, the sizes between the ducts must account for differences in the distance between the assembly protrusions.

Yet another embodiment of the invention is possible by using a connector provided with four assembly protrusions arranged in pairs one after the other as shown in fig. 8K. Then the plate elements comprise the pairs of two parallel assembly ducts along their edges (ail four ducts are parallel to each other). In such an embodiment, the first two adjacent assembly protrusions are mounted in the first plate element, each protrusion in a separate duct, and the second two protrusions are mounted in the second plate element in two assembly ducts, each protrusion in a separate duct. A similar variant of the invention can be achieved using a connector with six assembly protrusions arranged in six ducts (three in each adjacent plate element).

All elements of the set are preferably made of weather resistant materials. The connecting elements preferably have a lower hardness than the plate elements and are more flexible, e.g. made of plastic, rubber, caoutchouc or blends thereof.

Claims

1. A construction set for covering a substrate, in particular floor substrate, comprising plate elements for covering the substrate and connecting elements for joining together the adjacent plate elements, while maintaining a fixed distance between them to form a dilatation gap, characterized in that the connecting elements (2) comprise at least two, located on a base (3), assembly protrusions (4) sealed in the adjacent connected plate elements (1) equipped on their substrate side, along at least two opposing side edges, on at least part of their length, in equal distance therefrom, with assembly ducts (7) of similar a cross-section, with the connecting elements (2) joining the adjacent plate elements (1) seated therein, by means of the assembly protrusions (4), wherein when the plate elements (1) are provided only with assembly ducts (7) parallel to each other and located only along two opposing side edges of plate elements, then these elements optionally comprise also the assembly hoies (8) located by the edges without the assembly ducts (7), in which holes (8), at least in some of them, assembly protrusions (4) of the connecting elements are seated.

2. A construction set according to claim 1 , characterized in that the plate elements (1 ) are cuboidal, having the identical thickness, and assembly ducts (7) are guided through the perpendicular edges of the plate elements

(I) or do not reach these edges.

3. A construction set according to claim 1 or 2, characterized in that the assembiy ducts (7) in the plate elements (1 ) are located along all edges of these elements, at least part of their length.

4. A construction set according to claim 1 or 2 or 3, characterized in that the plate elements (1 ) comprise more than two mutually parallel assembiy ducts, preferably three, four, five or six.

5. A construction set according to any one of claims 1 to 4, characterized in that the plate elements may be solid or ribbed and/or comprise recesses

(II) or internal chambers (12) or ribs (13) reducing the weight of these elements, optionally such recesses may have a cross section and a mould the same as the assembly ducts.

6. A construction set according to any one of claims 1 to 5, characterized in that when it consists of the plate elements (1 ) of various sizes then optionally, the length and/r width of the plate elements is interdependent and depends on the width of the set dilatation gap so that the length and/r width of the elements is a multiple of the smallest width or length of the plate element increased by the sum of the widths of the dilatation gaps corresponding to that multiple.

7. A construction set according to any one of claims 1 to 5, characterized in that the connecting elements (2) are equipped with at least two assembly protrusions (4), located on the base (3).

8. A construction set according to any one of claims 1 to 7, characterized in that the connecting elements (2) are equipped with at least one through assembly hole (14), located on the base.

9. A construction set according to any one of claims 1 to 8, characterized in that the connecting elements (2) are equipped with adjustment protrusions (5) positioning a dilatation gap between the plate elements (1 ), wherein the adjustment protrusions (5) optionally comprise additional convex profiles (6) connecting the side walls of the plate elements (1 ).