EP1512807B9 - Element with thin middle layer for floor covering - Google Patents

Abstract

The element for a floor covering with a middle layer (2) and cover layer (D) has a tongue-in-groove connection method for connecting to other similar elements. The middle layer has a thickness (S) of up to 6 mm, and the short cheek (12) of the groove extends parallel to the upper side (4) of the element. The distance between the underside of the short cheek and upper side of the middle layer comes to 23-24 per cent of the middle layer thickness. The long cheek (16) of the groove is angled with regard to the underside (6) of the middle layer. The tongue has a thickness of 43-44 per cent with regard to the thickness of the middle layer.

Description

The invention relates to an element for a floor covering with a thin middle layer of rigid material, in particular with a middle layer of a wood material having coupling profiles for coupling further, the same elements. The coupling profiles are shaped in the manner of a tongue and groove joint and worked out on two longitudinal edges of the element and possibly on two transverse edges. The coupling profiles allow a permanent assembly of the elements without additional aids such. Glue. The execution of the coupling profiles takes into account in particular the material properties of the middle layer material to be used.

Glueless coupling profiles can be easily divided into two main groups. On the one hand in so-called "click" connections, in which in addition to the known coupling profiles still elastic locking profiles are provided and / or the coupling profile is designed to be elastic. On the other hand elements are known which can be added by pivoting and thereby require by the positive engagement of the coupling profiles during pivoting any elastic movement of the coupling profile.

Floor coverings made of elements with glueless coupling profiles have been widely used as laminate flooring. Laminate floors are characterized by high-strength middle layers. The decorative cover layers and backing layers of laminate flooring attached to the underside increase the total thickness of the floor element insignificantly, but contribute significantly to the additional increase in the stability of the elements and their coupling profiles and / or locking profiles, since these cover and Gegenzugschichten the surfaces of the elements additional strength to lend. This very stable construction of cover layer, middle layer and backing allows to produce laminate floors with glueless coupling profiles in thicknesses from 10mm down to 7mm. When working out the coupling profiles, the entire element thickness is available due to the stable construction.

Furthermore, floor coverings made of elements with glueless coupling profiles as parquet floors have also found widespread use. Parquet floors are characterized by middle layers of solid wood, on which cover layers and counter layers are also glued. The outer layers and Gegenzugschichten are of their strengths and material properties such that they are suitable for working out a coupling profile or portions of a coupling profile. Therefore, even with parquet floors, the entire element thickness is available to work out the glueless coupling profile. Parquet floors with glueless coupling profiles are manufactured from 20mm down to 13mm.

In addition, floor coverings made of elements which have cover layers of low strength have also found widespread use as finished floors with glueless coupling profiles. Such finished floor coverings also have middle layers, on which the outer layers and Gegenzugschichten are glued. The cover layers can be made of various materials such. As cork, linoleum, rubber, veneer or other coverings exist. As Gegenzugschichten simple papers and / or materials such as cork, cardboard, natural and artificial insulation boards, etc. can be used. In contrast to the two aforementioned types of laminate flooring and parquet floors, the total thickness of the element can not be used here to work out the coupling profiles.

Both the outer layers and the Gegenzugschichten are due to their material properties, in particular because of the low density and low strength properties such that they are not suitable for working out the coupling profiles or a portion of the coupling profiles. The wooden materials used for middle layers of finished floor coverings with low-strength cover layers can therefore, in contrast to laminate floors or parquet, not achieve any additional strength and additional gain in strength for the coupling profile via the cover layers and the backing layers. At the same time, this type of floor coverings requires middle layers which make it possible to allow a sufficient connection, preferably bonding, of the top and back layers with the middle layer. A surface finish with the associated strength gain of Middle layer such as laminate floors are not possible. Thus, only the middle layer is available to work out the glueless coupling profile in strength.

The strength of the profile can not be reduced arbitrarily, since a coupling profile on the one hand must be able to be worked out by conventional machining methods and on the other sufficient strength of verkuppelten elements must be guaranteed. The minimum total thickness of the footpad element is determined first by the middle layer from which the coupling profiles are worked out, and only then by the thicknesses of the cover layer and the counteracting layer. The thicknesses of the cover and Gegenzugschichten can vary depending on the design, the middle layer with the machined coupling profile is made according to the current state of the art of 7 to 10mm. The dimensioning of the coupling profiles is based on the material-specific strength values of the middle layer and on the available middle layer thickness. In the aforementioned construction, the existing state of the art results in overall thicknesses of a floor element of 10 to 15 mm.

The WO 01/53628 suggests for foot well elements with a 6 to 9 mm thick middle layer a locking arrangement which is located far down in the middle layer and which has a short locking surface. The AT 321529 describes building panels with a locking arrangement that secures against horizontal and vertical displacement of the panels.

When installing in existing apartments but often only floor coverings can be laid to about 6 to 8 mm. Any stronger pad requires major modifications or changes to the door panels, etc. Regardless of the topcoat applied to the top of a middle layer and the strength of the counteracting layer, it has been found that a maximum thickness of 6 mm should be chosen for the middle layer , if it should be ensured that the floor covering readily available in existing homes, such. B. in exchange for carpet, can be laid.

For floor coverings, as they were described in the aforementioned way, you went so far assuming that the coupling profiles can not be sufficiently stable as a groove-and-spring connection, if the above mentioned minimum thickness of the middle layer of 7 now falls below the present state of the art. Sufficient stability is ensured if, in the case of a laid surface, the coupled profiles remain permanently closed in the event of swelling and shrinkage stresses and superimposed dynamic loads, or show only minimal joints. The coupling profiles must be for many years be able to absorb the loads without being damaged.

The stability of a coupling profile can only be assessed taking into account the superimposed forces acting on the installed floor coverings. The shrinkage stresses acting in the horizontal direction can not be considered in isolation because they are caused by simultaneously acting dynamic loading, e.g. Passing, vertical movements induced in the verkuppelten profile. The load capacity of a coupling profile decreases sharply when the superimposed vertical movements of the laid floor covering lead to movements within the coupling profile and / or lead to splitting of the middle layer and thereby to functional failure of the coupling profile or a portion of the coupling profile.

It is therefore an object of the invention to provide coupling profiles, which consist of very thin middle layers of conventional, inexpensive and easy weiterverarbeitbaren wood materials such. HDF are made, and allow a rigid and reliable connection of two elements and in particular a laid surface that withstands high loads.

This object is achieved with an element according to claim 1. Advantageous embodiments of the element according to the invention are claimed in the subclaims.

In the past, too little attention was paid to the construction of coupling profiles. For example, there are finished floor elements on the market whose coupling profiles, in particular the coupling profiles on the transverse sides of the finished floor elements, are undersized. These designs can only be used without damage in the long term, if the areas occupied by these elements are relatively small, the loading of the room by eg furniture is low, the dynamic load is low by eg walking and the swelling and shrinkage stresses by special measures of Room air conditioning are reduced.

Practical experience has shown that coupling profiles, which can be added by pivoting and thereby require by the positive engagement of the coupling profiles during pivoting no elastic movement of the coupling profile are durable in continuous use and can absorb higher loads. This is due, inter alia, to the fact that the elastic movements take place mainly in the direction perpendicular to the cover layer plane and the middle layer materials used consist of z. B. HDF can absorb high tensile and compressive forces, but with respect to the transverse tensile strength, compared to solid wood, have low strength. In particular, in the case of non-optimal assembly, overloading of the middle layer with the consequence of parallel cracks can occur to the deck level.

For the development of coupling profiles for thin middle layers, it is not enough to reduce the size of successful coupling profiles only to scale. By reducing the middle layer thickness, the superimposed forces shift in their proportions, because the flexural rigidity decreases with the middle layer thickness, whereas the horizontal forces remain unchanged due to swelling and shrinkage stresses.

At the same time, it should be taken into account that, if the coupling profile is reduced to scale, the load-bearing profile sections are also reduced, thereby resulting in a reduction of the load capacity of the coupling profile.

Also, scaling down the coupling profile also increases the accuracy with which the elements must be pivoted into one another. The danger that the coupling profile is pivoted, although the corresponding groove and spring of the coupling profile has not been assembled with the necessary accuracy before, increases in a scale reduction of the coupling profile. Damage to the coupling profile is the result.

There is also the danger that plate through the elastic properties of the wood material at low middle layer thicknesses fundamental assembly errors occur. Small profile sections of the coupling profile can dodge due to the elasticity of the wood-based panel. Due to yielding, elastic profile sections would be It is possible not to pivot the coupling profile as intended, but to beat horizontally together. This is already possible because there are products on the market which are constructed longitudinally for pivoting and transverse for hitting and therefore misunderstandings are possible. If a coupling profile, which is machined on the transverse side of the middle layer, and whose coupling profile sections are not stiff enough, instead of being pivoted as intended, but taken horizontally, then damage to the coupling profile is the result. It is therefore desirable that the coupling profiles, in particular those for the transverse edge, are designed constructively so that false assemblies are excluded, or that a wrong assembly can be clearly recognized by the publisher.

An element is known for a floor covering having a middle layer with a cover layer and possibly a counter-stretch of rigid material, in particular wood material, with a coupling profile machined out of the middle layer for coupling further, similar elements, wherein the coupling profile is designed in the manner of a tongue and groove Joint formed and attached to at least two edges of the element. The known element has at least a first longitudinal edge with a groove having a long groove cheek and a short groove cheek, wherein the groove is formed so that it receives a spring of a second element in the installed state, so that the two connected elements against a vertical movement and secured against a horizontal pulling apart.

According to the invention, such an element now has a middle layer having a thickness S of up to 6 mm, in which the short groove cheek is arranged substantially parallel to the top of the element, and the distance between the underside of the short groove cheek and the top of the middle layer to 23-24% of the strength of the middle layer (2). Next extends in the inventive element, the long groove cheek, based on the underside of the middle layer, angled, wherein a first portion which extends below the short groove cheek, is inclined from the groove bottom to the bottom, a second portion which adjoins the first portion , Runs substantially parallel to the bottom, a third section which is parallel to the second section and wherein a fourth section extending to the free end of the long Groove cheek connects to the third section, the top of the element increases towards, but has a maximum thickness of 75% of the thickness S of the middle layer. The thickness of the second portion of the long groove cheek is 33% of the thickness S of the middle layer of the element according to the invention. Further, the spring has a thickness of up to 44%, based on the thickness S of the middle layer, wherein the first contact surface 12a between the spring and short groove cheek a maximum of 30% of the total length of the free end of the spring, and wherein the second contact surface between spring and second portion of the long groove cheek is a maximum of 50% of the second portion of the long groove cheek.

For the functionality of the element according to the invention, it is further required that an angle α which is limited by a line and a straight line is up to about 16 °, and that a distance 24a which corresponds to the width of the fourth section, with respect to Distance which extends from the intersection of the abutment surface with the top of the spring to the transition of defined sections of the underside of the spring (see embodiment), in the ratio of 1: 2 stands.

The aforementioned design specifications make it possible to produce a profile that reliably grips and does not fail under extreme loads.

Fig. 1

eine verkuppelte Nut- und Feder-Verbindung an der Längskante eines Elements für einen Fußbodenbelag und

Fig. 2

eine verkuppelte Nut- und Feder-Verbindung an der Querkante eines Elements für einen Fußbodenbelag.

An exemplary embodiment shows by way of example essential details of the invention. It shows:

Fig. 1

a verkuppelte tongue and groove joint on the longitudinal edge of an element for a floor covering and

Fig. 2

a verkuppelte tongue and groove connection at the transverse edge of an element for a floor covering.

Fig. 1 shows the structure of the longitudinal edge of an element 1 of a floor covering. The middle layer 2 is made of HDF material. On top 4 of the middle layer a decorative layer D is applied. On the bottom 6 of the middle layer 2, a counter-pull G is applied. The floor element 1 is laid on the floor in the installed state. In a side surface 8 of the middle layer 2, a groove 10 is incorporated.

From the corresponding side edge 8 a complementary spring 3 is worked out. This groove 10 is according to Fig. 1 designed so that it receives a displaced state, a spring 3 of a second element, so that the two connected elements are secured against vertical movement and against a horizontal pulling apart. The groove 10 and the spring 3 are each incorporated in the longitudinal edges of the element 1. Fig. 2 shows a comparable arrangement, but for a transverse edge of an element.

The thus designed element has a middle layer thickness S of 6 mm, wherein the thickness can be reduced to 5 mm. The groove 10 has a short groove cheek 12, which runs parallel to the top 4. The thickness of this groove cheek 12 is based on the thickness S of the middle layer 23 to 24% of the thickness S. A first end of the short groove cheek 12 ends at the groove bottom 14. A second end of the short groove cheek 12 ends at or in the side surface 8. Der Groove base 14 extends perpendicular to the upper side 4 over 11 to 12% of the thickness S of the middle layer 2. At the lower end of the groove base 14, the long groove cheek 16 sets, which extends beyond the short groove cheek 12 out to a free end 18. A first portion 20 of the long groove cheek 16 extends from the groove bottom 14 to the bottom 6 and ends at the second portion 22 a, which runs parallel to the bottom 6. The second section 22a, having a thickness of 33% of the middle layer thickness S, merges into a weaker third section 22b whose thickness is 30% of the middle layer thickness S. The corresponding with the groove 10 spring 3 is located after the joining of two complementary elements 1 on the stronger second portion 22a. The weaker third portion 22b has no contact with the spring 3, therefore it allows a simpler displacement of second elements 1 parallel to its longitudinal axis.

Adjoining the weaker third section 22b, toward the free end 18 of the long groove cheek 16, is the fourth section 24, which rises from the third section 22b to the upper side 4. The fourth portion 24 has a maximum strength that does not exceed 75% of the thickness S of the middle layer. The distance from the end of the third portion 22b to the free end of the long groove cheek 16 is referred to as the width 24a of the fourth portion 24.

The element 1 has at the side edges 8 abutting surfaces 26. The abutment surfaces each extend from the short groove cheek 12 to the upper side 4 of the element 2 and from the upper side 28 of the spring 3 to the upper side 4 of the element 1. The abutting surfaces 26 face each other in the case of corresponding or interlinked elements 1, but they run not always straight. They may have recesses or be arranged at a distance from each other.

The spring 3 extends with a freely projecting part 5 of the abutting surface 26 of the element 1 to a free end 30, which faces the groove bottom 14. The first contact surface 12a may be arranged in a plane with the upper side 28 or extend at a distance therefrom. Below the free end 30, the underside 32 of the spring 3 extends substantially corresponding to the sections 1 to 4 of the long groove cheek 16. The length of the second bearing surface 22a between the spring 3 and the second portion 22a of the long groove cheek is about 30% of Length of the second section of the long groove cheek. In this case, the portion of the underside 32, which spans the sections 22 and 22b, be flat, so that in the assembled state, the bottom 32 abuts the portion 22a, the portion 22b but has a distance.

The fourth section 24 of the longer groove cheek 16 is received in a recess 34 with the free end 18. The recess 34 is bounded by a lower abutment surface 36 and by portions of the underside 32 of the spring 3. The underside 32 is divided over the fourth portion 24 of the longer groove cheek in three sections 32a, 32b and 32c. The portion 32a extends from the bottom 32 of the spring 3 to the top 4 of the element 1. At this portion 32a, the portion 32b connects, which extends approximately horizontally. Section 32b terminates at its other end at portion 32c, which is inclined downwardly to the bottom 6 of the element 1 and terminates at the lower abutment surface 36. The overall length of the spring 3 extends from the lower abutment surface 36 to the free end 30 of the spring.

The secure engagement of groove 10 and spring 3 is ensured when the following conditions are met: An angle α is bounded by a line 38, the the top 28 of the spring 3 continues horizontally and parallel with respect to the top 4 of the element 1 and from a straight line 24b extending from the intersection of the line 38 with the abutment surface 26 up to the interface between the section 32a and the section 32b , The angle α is 13 ° for a longitudinal edge profile and 16 ° for a transverse or end edge profile (cf. Fig. 2 ). The width 24a of the fourth portion 24 is 1: 2 in relation to the straight line 24b. The dimensioning of the width 24a depends on the shear tensile strength of the middle layer and the loading parameters of the laid surfaces.

The spring 3 has in its free portion a thickness of 43 to 44%, based on the thickness of the middle layer of the element on. In the profile version for the longitudinal edge ( Fig. 1 ), the length of the first contact surface 12a between the spring and the short groove cheek is 23 to 24% of the thickness of the middle layer. In the profile version for the transverse edge ( Fig. 2 ), the length of the first contact surface 12a between spring and short groove cheek is about 15% of the thickness of the middle layer.

This dimensioning ensures that the tongue and groove connection is somewhat stiff, so that it does not yield or crack even under heavy load and / or during pivoting. The above design rules for the spring, its strength and the relationship of the contact surfaces to each other ensures that the connection is easy to produce by pivoting and holds reliably. The design rules are based on uncoated HDF boards to be glued with dispersion adhesives with densities of 850 to 950 kg / m ² with typical transverse tensile strengths of approx. 1.4 to 1.8 N / mm ² , with typical bending strengths of 40 to 50 N / mm ² and on usual loads of the laid surface in living space usual size of up to 70 m ² .

The total thickness of the floor element may exceed 6 mm if a decorative layer D is applied to the top 4 and / or a backsheet layer is applied to the bottom 6 of the middle layer 2, and these layers exceed the thickness of a decorative paper. For example, cork and linoleum are processed in thicker layers of about 2 mm.

These relatively small bearing surfaces 12a and 22a are sufficient for vertical positioning of the tongue and groove joint. In the Fig. 2 in the representation of the transverse edge profile reduced bearing surfaces take into account a displacement of the verkuppelten transverse edge profile, which is necessary during assembly. The angle α in conjunction with the dimension 24a and the consequent dimension 24b take into account the material properties of the middle layer and the superimposed loads of a laid floor. Their exact coordination and their relationship to each other, as well as the absolute dimension 24a ensure optimum coordination between the material properties, the middle layer thickness and the loads of the coupling profile by a laid floor.

An element according to the invention is usually rectangular in shape. It has the above-described groove on a longitudinal edge ( Fig.1 ) on. According to a common embodiment, one longitudinal edge with the above-described groove and a further longitudinal edge with the complementary spring are each designed. In addition, it has a prescribed groove on a transverse edge ( Fig.2 ) on. There is in each case a transverse edge provided with the above-described groove and a further transverse edge with the complementary spring.

Claims (11)

1. Element for a floor covering with a middle layer (2) with a cover layer (D) and, if applicable, a counter draw (G) made of a rigid material, in particular a wood product, with a coupling profile worked out of the middle layer for coupling other, similar elements, wherein the coupling profile is shaped according to the type of a groove and tongue connection and is attached to at least two edges of the element,

   - wherein the element has at least a first longitudinal edge with a groove (10), which has a long (16) groove sidewall and a short (12) groove sidewall and the groove (10) is designed such that it receives in the shifted position a tongue (3) of a second element such that the two connected elements are secured against a vertical movement and against a horizontal pulling apart,

   - wherein the middle layer (2) of the element has a thickness (S) of up to 6 mm,

   - wherein the long groove sidewall (16), relating to the bottom side (6) of the middle layer (2), runs offset, wherein a first section (20), which runs below the short groove sidewall (12), is tilted from the groove base (14) towards the bottom side (6), a second section (22a), which connects to the first section (20), runs mainly parallel to the bottom side (6), a third section (22b), which runs parallel to second section (22a) and a fourth section (24), which connects towards the free end (18) of the long groove sidewall (16) to the third section (22b), increases towards the top side (4) of the element,

   - wherein the fourth section (24) of the long groove sidewall (16) extends from the end of the third section (22b) up to the free end of the long groove sidewall (16),

   - wherein the element (1) has abutting faces (26), each of which extend from the short groove sidewall (12) up to the top side (4) of the element (1) and from the top side (28) of the tongue (3) to the top side (4) of the element (1), and

   - wherein below the free end (30) of the tongue (3), the bottom side (32) of the tongue runs mainly corresponding to the four sections of the long groove sidewall (16), wherein the bottom side (32) of the tongue over the fourth section (24) of the long groove sidewall (16) has a first section (32a), which is tilted from the bottom side (32) of the tongue (3) towards the top side (4) of the element (1), wherein a second section (32b), which runs mainly parallel to the top side (4) of the element (1), is connected to this first section,

   - wherein a line (38), which continues the top side (28) of the tongue (3) horizontal and parallel to the top side (4) of the element (1), and a straight line (24b), which extends from the intersection point of the line (38) with the abutting face (26) of the tongue up to the intersection point between the first section (32a) of the tongue and the second section (32b) of the tongue, incorporate an angle (α) and wherein

   - the short groove sidewall (12) is arranged mainly parallel to the top side (4) of the element,

   characterized in that

   - the distance between the bottom side of the short groove sidewall (12) and the top side (4) of the middle layer (2) is 23 to 24% of the thickness of the middle layer (2),

   - the thickness of the second section (22a) of the long groove sidewall (16) is 33% of the thickness (S) of the middle layer (2) of the element,

   - the long groove sidewall however has a thickness of max. 75% of the thickness (S) of the middle layer (2),

   - the tongue has a thickness of 43 to 44%, relating to the thickness (S) of the middle layer, and wherein

   - the length of the first contact surface (12a) between the tongue and the short groove sidewall (12) is max. 30% of the overall length of the free end of the tongue (3),

   - the length of the second contact surface (22a) between the tongue and the second section (22a) of the long groove sidewall (16) is max. 50% of the length of the second section (22a) of the long groove sidewall (16), and

   - wherein the distance (24a), which corresponds with the width of the fourth section (24), with respect to the distance (24b), which extends from the intersection point of the abutting face (26) with the top side (28) of the tongue (3) up to the transition of the first section (32a) of the tongue to the second section (32b) of the tongue (3), is at a ratio of 1:2, and

   - wherein the angle (α), which is bordered by the line (38) and the straight line (24a), is up to approx. 16°.
2. Element according to claim 1, characterized in that the coupling means are designed as a swivel connection.
3. Element according to claim 1, characterized in that the rigid material is a wood product, in particular a fiberboard, preferably a medium-density fiberboard or a high-density fiberboard.
4. Element according to claim 1, characterized in that the longitudinal edges and the transverse edges have deviating profiles.
5. Element according to claim 1, characterized in that the tongue (3) of the longitudinal edges and the transverse edges have a thickness of up to 44% of the thickness (S) of the middle layer.
6. Element according to claim 1, characterized in that the angle (α) is up to 13° for the longitudinal edge and up to 16° for the transverse edge.
7. Element according to claim 1, characterized in that the thickness of the second section (22a) is 33% of the thickness (S) of the middle layer (2) of the element and passes into a weaker section (22b), the thickness of which, relating to the bottom side (6) of the middle layer (2), is 30% of the thickness (S) of the middle layer of the element.
8. Element according to claim 1, characterized in that the first section (20) runs as a straight line from the groove base (14) to the second section (22a) of the long groove sidewall (16).
9. Element according to claim 1, characterized in that a groove base (14) is arranged between the short (12) and the long groove sidewall (16), which extends mainly perpendicular to the top side (4) of the element.
10. Element according to claim 9, characterized in that the groove base (14) is 11 to 12% of the thickness (S) of the middle layer (2).
11. Element according to claim 1, characterized in that a decorative layer (D), in particular a decorative paper, a cork layer, a linoleum layer or a veneer layer, is applied to the top side (4) of the element.

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