This invention relates to a composed element, as well as to a corner connection which is applied herewith.

More particularly, the invention relates to a composed element which comprises at least two panel-shaped elements, which are coupled to each other, can be coupled to each other, respectively, at an angle to form a corner connection. The invention relates to any form of composed element which comprises at least two or more panelshaped elements, irrespective of the field of application, and irrespective of the fact whether the composed element substantially consists exclusively of the panel-shaped elements or whether these panel-shaped elements only form a part thereof.

Although the invention can be used in any application, it is intended in the first place for being applied in the furniture sector, with individual pieces of furniture as well as with built-in furniture, such as dressing furniture, room dividers and the like.

The invention aims particularly at connections between panel-shaped elements, which can be realized in a smooth manner and are suitable for being employed with furniture which is sold in dismantled condition and must be assembled by the buyer himself. This relates in the first place to so-called flat-pack furniture.

The invention relates particularly to a composed element which comprises two or more panel-shaped elements, which each comprise a coupling zone in which coupling parts are present in the form of a profile respectively extending in the longitudinal direction of the respective coupling zone, preferably in the form of a tongue and a groove, respectively, wherein these profiles allow that the panel-shaped elements can be coupled to each other in a locking manner and at an angle. Such composed element is known from W02010/070472, W02010/070605 and The use of such profiles, which are provided in the panel-shaped elements themselves and are made entirely or for the major part in one piece therewith, offers the advantage that no separate elements are required for connecting the panel-shaped elements at an angle, such as, for example, metal connection elements, or at least the use of such separate elements can be limited to a minimum. Another advantage thereof consists in that such profiles can be milled in a simple manner into the panelshaped elements and that a continuous locking coupling can be realized along the entire corner connection.

It is clear that such coupling, during coupling as well as after coupling, is subjected to forces. Considering that the profiles in fact mostly have to be realized in relatively thin panels and more over also often have to be suited for being realized in particle board, which, as known, is brittle, the known profiles offer only a limited number of possibilities for optimization.

Thus, the present invention aims at improving such composed element, in particular of the type as described in WO2010/070472, WO2010/070605 and WO2021/151758A2.

The present invention aims specifically to improve the ease of coupling of the panelshaped elements into a corner connection.

The first aspect of the invention is a composed element which comprises at least a first and a second panel-shaped element, which, by means of a locking tongue and groove connection, can be coupled directly to each other thereby forming a corner connection, wherein the connection comprises, at least at the first panel-shaped element, a tongue, which can cooperate with a groove provided on the second panelshaped element; wherein the tongue extends from the surface of a small face of the first panel-shaped element. The composed element is characterized in that the tongue comprises a tip provided at the distal end of the tongue, wherein the tip has a tangent plane, called the first tangent plane; wherein the angle between the first tangent plane and the small face of the first panel-shaped element is at least 5°, preferably at least 7°, more preferably at least 10°, even more preferably at least 12°, even more preferably at least 15°.

The composed element of the first aspect of the invention has the benefit that coupling of the first panel-shaped element onto the second panel-shaped element is facilitated, as entrance of the tip of the tongue into the groove is facilitated.

The second aspect of the invention is a composed element which comprises at least a first and a second panel-shaped element, which, by means of a locking tongue and groove connection, can be coupled directly to each other thereby forming a corner connection, wherein the connection comprises, at least at the first panel-shaped element, a tongue, which can cooperate with a groove provided on the second panelshaped element; wherein the tongue extends from the surface of a small face of the first panel-shaped element. The composed element is characterized in that the tongue comprises a tip provided at the distal end of the tongue, wherein the tip has a tangent plane, called the first tangent plane; wherein the groove comprises a bottom provided by the deepest section of the groove, wherein the bottom has a tangent plane, called the second tangent plane; wherein the angle between the first tangent plane and the second tangent plane is at least 5°, preferably at least 7°, more preferably at least 10°, even more preferably at least 12°, even more preferably at least 15°.

The composed element of the second aspect of the invention has the benefit that coupling of the first panel-shaped element onto the second panel-shaped element is facilitated, as entrance of the tip of the tongue into the groove is facilitated.

A preferred embodiment of the first aspect and/or of the second aspect of the invention is characterized in that in coupled condition the tip of the tongue is located at - and preferably opposes - the bottom of the groove. Such embodiments facilitate the ease of coupling even more.

A preferred embodiment of the first aspect and/or of the second aspect of the invention is characterized in that the tip of the tongue comprises a planar section, wherein the first tangent plane is the tangent plane to the planar section of the tip. Such embodiments facilitate the ease of coupling even more.

A preferred embodiment of the first aspect and/or of the second aspect of the invention is characterized in that the bottom of the groove comprises a planar section, wherein the second tangent plane is the tangent plane to the planar section of the bottom of the groove. In such embodiment, extra room is provided for the tip to be positioned in the groove, thereby facilitating the coupling.

A preferred embodiment of the first aspect and/or of the second aspect of the invention is characterized in that the second tangent plane is parallel with the surface of the second panel-shaped element. When the second tangent plane is parallel with the surface of the second panel-shaped element, maximal room is provided for the tongue to enter and be positioned in the groove.

A preferred embodiment of the first aspect and/or of the second aspect of the invention is characterized in that the tongue has a thickness, wherein the thickness of the tongue is measured at the surface of the small face of the first panel-shaped element from which the tongue extends; wherein the tip of the tongue is situated at the bottom half of the thickness of the tongue; wherein the first tangent plane is oriented from the bottom half of the tongue towards the upper half of the thickness of the tongue. Thanks to the position of the tip of the tongue, the tongue can be more easily introduced into the groove, especially - but not only - when performing the coupling by means of a turning movement.

More preferably, the tip of the tongue is provided entirely in the bottom half of the tongue. In such embodiments, inserting the tongue into the groove is even more easy.

A preferred embodiment of the first aspect and/or of the second aspect of the invention is characterized in that the tongue consists of a split tongue, with, thus, at least a first part and a second part, as well as a slit located there between.

Such embodiments provide a certain flexibility to the tongue, facilitating the insertion of the tongue into the groove and the quality of the locking of the comer connection. Composed elements according to the first aspect and/or according to the second aspect of the invention have the benefit that the size of the slit can be reduced. The slit can be made less deep and/or less thick.

Preferably, the thickness of the slit is at most 2 mm; more preferably at most 1.8 mm; even more preferably at most 1.5 mm. Such embodiments have the benefit that the strength of the tongue is not affected much as the thickness of the slit can be kept limited thanks to the features of the invention, while coupling can be performed easily.

Preferably, the slit extends deeper than the surface of the small face of first panelshaped element from which the tongue extends. Even more flexibility is provided to the tongue in such embodiments.

Preferably, the slit is delimited at least by a first inner surface of the tongue, a second inner surface of the tongue and a bottom;. More preferably, the first inner surface and the second inner surface are parallel with each other. Such embodiments are beneficial, as the slit can be more easily made into the tongue.

More preferably, at least one of the first inner surface or the second inner surface, is not parallel with the large parallel surfaces defining the length and width of the first panel-shaped element, wherein the first inner surface and/or the second inner surface, respectively, which is not parallel with the large parallel surfaces defining the length and width of the first panel-shaped element is not parallel with the large parallel surfaces defining the length and width of the first panel-shaped element at least for the part of the slit which reaches deeper than the surface of the small face of the first panel-shaped element. Such embodiments provided increased ease of coupling, thanks to a tuning of the flexibility of the tongue split into two parts.

In alternative embodiment, the slit can be parallel with the surface of the first panelshaped element.

Preferably, the first part of the tongue protrudes farther from the small face of the first panel-shaped element than the second part of the tongue.

More preferably, the tip of the tongue is provided in the first part of the tongue. Such embodiments make it even more easy to insert and couple the tongue into the groove. This benefit is even more pronounced when the first part of the tongue protrudes farther from the small face of the first panel-shaped element than the second part of the tongue

The third aspect of the invention is a composed element, optionally a composed element as in any embodiment of the first aspect and/or the second aspect of the invention. The composed element comprises at least a first and a second panel-shaped element, which, by means of a locking tongue and groove connection, can be coupled directly to each other thereby forming a corner connection, wherein the connection comprises, at least at the first panel-shaped element, a tongue, which can cooperate with a groove provided on the second panel-shaped element; wherein the tongue extends from the surface of a small face of the first panel-shaped element; wherein the groove is provided in a surface of the second panel-shaped element. The composed element of the third aspect of the invention is characterized in that at least at one side of the groove the transition section between the surface of the second panel-shaped element and the groove comprises at its bending point or bending section a radius of curvature of at least 0.7 mm, and preferably of at least 1 mm.

Such composed elements are beneficial as additional space is provided for the tongue to enter the groove during coupling the tongue into the groove. This way, ease of coupling of the first panel-shaped element onto the second panel-shaped element is facilitated.

The fourth aspect of the invention is a composed element, optionally a composed element as in any embodiment of the first aspect and/or the second aspect and/or the third aspect of the invention. The composed element comprises at least a first and a second panel-shaped element, which, by means of a locking tongue and groove connection, can be coupled directly to each other thereby forming a corner connection, wherein the connection comprises, at least at the first panel-shaped element, a tongue, which can cooperate with a groove provided on the second panelshaped element. The tongue extends from the surface of a small face of the first panel-shaped element. The groove is provided in a surface of the second panelshaped element. The composed element of the fourth aspect of the invention is characterized in that at least at one side of the groove the transition section between the surface of the second panel-shaped element and the groove comprises from the surface of the second panel-shaped element towards the groove a first section, a bending point or bending section and a second section; wherein the tangent plane to the first section has an included angle with the surface of the second panel-shaped element which is larger than 130°, and preferably larger than 140° and preferably larger than 150°.

Such composed elements have the benefit that the ease of coupling is improved, as more room is provided for the tongue to enter the tongue and for the tongue to be coupled correctly into the groove without a lot of effort.

A preferred embodiment of the invention according to the first aspect and/or second aspect, and according to the fourth aspect of the invention is characterized in that the included angle between the first tangent plane and the tangent plane to the first section is less than 30°, preferably less than 20° even more preferably less than 15°. Such embodiments facilitate the entrance of the tongue in the groove when coupling, and facilitate the overall coupling, especially - but not only - when the coupling is performed via a turning movement.

The fifth aspect of the invention is a composed element, optionally a composed element as in any embodiment of the first aspect and/or the second aspect and/or the third aspect and/or the fourth aspect of the invention. The composed element comprises at least a first and a second panel-shaped element, which, by means of a locking tongue and groove connection, can be coupled directly to each other thereby forming a comer connection, wherein the connection comprises, at least at the first panel-shaped element, a tongue, which can cooperate with a groove provided on the second panel-shaped element. The tongue extends from the surface of a small face of the first panel-shaped element. The groove is provided in a surface of the second panel-shaped element. The composed element of the fifth aspect of the invention is characterized in that at least at one side of the groove the transition section between the surface of the second panel-shaped element and the groove comprises from the surface of the second panel-shaped element towards the groove a first section, a bending point or bending section and a second section; wherein the tangent plane to the second section has an included angle with the surface of the second panel-shaped element which is larger than 115°, and preferably larger than 120°, more preferably larger than 125°.

The first and second panel-shaped elements of the composed element of the fifth aspect of the invention can be coupled to each other more easily, thanks to more room which is provided for the tongue to enter the groove.

A preferred embodiment is characterized in that the bending point or the center of the bending section is provided at a distance of at least 0.75 mm, and preferably at a distance of at least 0.8 mm, from the surface of the second panel-shaped element. Such embodiments are preferred as introducing the tongue into the groove is facilitated even more.

A preferred embodiment is characterized in that the groove comprises a first bottom and a second bottom, wherein the first bottom is provided deeper than the second bottom, wherein the transition section is provided at the side of the groove comprising the second bottom. The first bottom is provided for receiving the most distal part of the tongue, while the second bottom provided room for the coupling to be performed more easily, especially thanks to the positioning of the second bottom.

A preferred embodiment is characterized in that the tongue consists of a split tongue, with, thus, at least a first part and a second part, as well as a slit located there between.

Such embodiments provide a certain flexibility to the tongue, facilitating the insertion of the tongue into the groove. Composed elements according to the third aspect and/or according to the fourth aspect and/or to the fifth aspect of the invention have the benefit that the size of the slit can be reduced. The slit can be made less deep and/or less thick.

A preferred embodiment is characterized in that the slit extends deeper than the surface of the small face of first panel-shaped element from which the tongue extends.

Preferably, the thickness of the slit is at most 2 mm; more preferably at most 1.8 mm; even more preferably at most 1.5 mm. Such embodiments have the benefit that the strength of the tongue is not affected much as the thickness of the slit can be kept limited thanks to the features of the invention, while coupling can be performed easily.

Preferably, the slit is delimited at least by a first inner surface of the tongue, a second inner surface of the tongue and a bottom;. More preferably, the first inner surface and the second inner surface are parallel with each other. Such embodiments are beneficial, as the slit can be more easily made into the tongue.

More preferably, at least one of the first inner surface or the second inner surface, is not parallel with the large parallel surfaces defining the length and width of the first panel-shaped element, wherein the first inner surface and/or the second inner surface, respectively, which is not parallel with the large parallel surfaces defining the length and width of the first panel-shaped element, is not parallel with the large parallel surfaces defining the length and width of the panel-shaped element at least for the part of the slit which reaches deeper than the surface of the small face of the first panel-shaped element. Such embodiments provided increased ease of coupling, thanks to a tuning of the flexibility of the tongue split into two parts.

Preferably, the first part of the tongue protrudes farther from the small face of the first panel-shaped element than the second part of the tongue.

More preferably, in coupled condition of the tongue and the groove, the second part of the tongue is located at the side of the groove comprising the transition section. Such embodiments make it even more easy to insert and couple the tongue into the groove. This benefit is even more pronounced when the first part of the tongue protrudes farther from the small face of the first panel-shaped element than the second part of the tongue.

A preferred embodiment according to any aspect of the invention is characterized in that in coupled condition the comer connection provides an inner corner and an outer corner, wherein at the outer comer contact is established between the surface of the second panel-shaped element and the small face of the first panel-shaped element, wherein the planar surface of the small face extends in the direction towards the tongue beyond the planar surface of the second panel-shaped element.

Such embodiments are beneficial as more room is provided for the tongue to enter the groove, facilitating the coupling operation.

A preferred embodiment according to any aspect of the invention is characterized in that the tongue consists of a split tongue, with, thus, at least a first part and a second part, as well as a slit located there between; wherein the slit is delimited at least by a first inner surface of the tongue, a second inner surface of the tongue and a bottom. Preferably, at least one of the first inner surface or the second inner surface is not parallel with the large parallel surfaces defining the length and width of the first panel-shaped element.

Such embodiments provide a certain flexibility to the tongue, facilitating the insertion of the tongue into the groove. Composed elements according to the first aspect and/or according to the second aspect of the invention have the benefit that the size of the slit can be reduced. The slit can be made less deep and/or less thick.

A preferred embodiment according to any aspect of the invention is characterized in that the first part of the tongue protrudes farther from the small face of the first panelshaped element than the second part of the tongue.

A preferred embodiment according to any aspect of the invention is characterized in that the thickness of the slit is at most 2 mm; more preferably at most 1.8 mm; even more preferably at most 1.5 mm. Such embodiments have the benefit that the strength of the tongue is not affected much as the thickness of the slit can be kept limited thanks to the features of the invention, while coupling can be performed easily.

A preferred embodiment according to any aspect of the invention is characterized in that the slit extends deeper than the surface of the small face of first panel-shaped element from which the tongue extends. Extra flexibility is provided to the tongue in such embodiments, facilitating the coupling operation.

A preferred embodiment according to any aspect of the invention is characterized in that the first inner surface and the second inner surface show a course deviating from the large parallel surfaces defining the length and width of the first panel-shaped element, wherein the first inner surface and the second inner surface substantially extend globally inclined, and more particularly, seen in cross-section, are straight- lined over the major part of their length. Such embodiments facilitate the coupling of the tongue into the groove, as an optimal flexibility is provided to the tongue.

Preferably, the first inner surface and/or the second inner surface, respectively, which is not parallel with the large parallel surfaces defining the length and width of the first panel-shaped element, is not parallel with the large parallel surface defining the length and width of the first panel-shaped element at least for the part of the slit which reaches deeper than the surface of the small face of the first panel-shaped element. Such embodiments provided even further improved ease of coupling the tongue into the groove.

In alternative embodiment, the first inner surface and the second inner surface are parallel with the large parallel surfaces defining the length and width of the first panel-shaped element. The slit of the tongue can be more easily manufactured in such embodiments.

Preferably, the distance with which the slit extends from the surface of the small face inwardly in the first panel-shaped element is larger than the largest distance by which the tongue reaches up to outward of the surface of the small face. Such embodiments further improve the ease of coupling, thanks to optimal flexibility of the tongue.

Preferably, a locking part is present at the outer side of at least the first part. It is a benefit of such embodiment that the location of the locking part does not hinder the coupling. Therefore, such embodiments provided increased ease of coupling.

Preferably, the second part of the tongue is free from locking parts. It is a benefit of such embodiments that thanks to the optimized position of the locking part of the tongue, the position of the locking part does not hinder the coupling operation. Therefore, such embodiments provide increased ease of coupling.

A preferred embodiment according to any aspect of the invention is characterized in that the slit, globally seen, extends at an angle, with parallel first and second inner surfaces. Such embodiments provide improved flexibility of the tongue, increasing the ease of coupling.

A preferred embodiment according to any aspect of the invention is characterized in that the tongue and the groove are configured such that they can be turned into each other, wherein the angle from which they can be turned into each other forms an inner corner.

A preferred embodiment according to any aspect of the invention is characterized in that the tongue has a thickness, wherein the thickness of the tongue is measured at the surface of the small face of the first panel-shaped element; wherein the tongue extends further from the small face at the bottom half of the thickness of the tongue than at the upper half of the thickness of the tongue, wherein in coupled condition the bottom half of the thickness of the tongue is situated closest to the inner corner.

Such embodiments facilitate coupling of the tongue into the groove, especially when the coupling is performed by means of a turning movement.

A preferred embodiment according to any aspect of the invention is characterized in that the tongue is located eccentrically, preferably in coupled condition in the direction of the inner comer of the corner connection. Such embodiments facilitate the insertion of the tongue into the groove in the initial phase of the coupling, thereby facilitating the whole coupling operation.

A preferred embodiment according to any aspect of the invention is characterized in that the tongue comprises a first locking part for cooperation with a second locking part provided in the groove, wherein the cooperation of the first locking part and the second locking part prevent in coupled condition the drifting apart of the tongue and groove, wherein, upon the cooperation a pair of contact surfaces is formed between the first locking part and the second locking part.

A preferred embodiment according to any aspect of the invention is characterized in that the tongue and the groove are configured such that they can be brought into a mutually coupled condition by means of a turning movement as well as by means of a displacement towards each other, which displacement is combined with a snap action. As the coupling can be performed in two different ways, coupling is made more easy, as in some situations due to room constraints when coupling the panelshaped elements, insufficient room is available for performing one of the two ways of coupling.

A preferred embodiment according to any aspect of the invention is characterized in that the tongue is made in one piece with the first panel-shaped element, and preferably formed in the material itself, from a basic board with which the first panelshaped element is formed. No inserts are required for the coupling parts, which facilitates the production of the tongue tremendously. As no inserts have to be positioned correctly during manufacturing of the coupling parts, a potential source of error that would make the coupling difficult or even impossible is avoided.

A preferred embodiment according to any aspect of the invention is characterized in that the groove is made in one piece in the second panel-shaped element, and preferably formed in the material itself, from a basic board with which the second panel-shaped element is formed. No inserts are required for the coupling parts, facilitating the production of the groove. As no inserts have to be positioned correctly during manufacturing of the coupling parts, a potential source of error that would make the coupling difficult or even impossible is avoided.

A preferred embodiment according to any aspect of the invention is characterized in that the first and of the second panel-shaped element, in respect to the material thereof, preferably show one or more of the following characteristics:

- the panel-shaped elements substantially consist of a basic board which is a woodbased pressed board;

- the panel-shaped elements substantially consist of a basic board formed of MDF (Medium Density Fiberboard) or HDF (High Density Fiberboard);

- the panel-shaped elements substantially consist of plywood;

- the panel-shaped elements substantially consist of a basic board formed of particle board;

- the panel-shaped elements are formed of melaminated board;

- the panel-shaped elements comprise a light-weight board, possibly with borders of another material;

- the panel-shaped elements are designed as a hollow board, or as a board provided with hollow spaces, for example, with a honeycomb core, possibly with borders of another material.

The above-mentioned materials offer the advantage that they are relatively inexpensive. The use of borders is useful when the board itself does not allow forming profiles therein, such as, for example, with honeycomb panels. The borders then may consist, for example, of laths, in which the desired profiles can be provided indeed.

A preferred embodiment according to any aspect of the invention is characterized in that the groove, seen in cross-section, is substantially and preferably entirely symmetrical.

Such embodiments provide the advantage that such groove can be formed easily by a finger milling cutter and that such groove can be realized as a dead-end groove, which requires special milling arrangements when a groove is realized by means of classical large milling tools. By making use of the symmetrical groove, new application possibilities are generated. Moreover, the same tongues can be applied as with the non-symmetrical grooves, such that for the tongues, the same set of milling tools or the like can be applied, irrespectively whether these are intended for cooperating with a symmetrical or an asymmetrical groove.

Furthermore, symmetrical grooves allow coupling from both directions. This is beneficial as panel-shaped elements comprising such grooves can be used in different kinds of composed elements, reducing the number of stock keeping units in the production of different composed elements.

The sixth aspect of the invention is a method for milling coupling parts to panelshaped elements, wherein the method comprises the steps of milling a first tongue extending from the surface of a small face of a first panel-shaped element and of milling a first groove on a second panel-shaped element; wherein the first tongue and first groove are configured for coupling by means of a locking tongue and groove connection the first-panel shaped element and the second-panel shaped element thereby forming a comer connection. The method is characterized in that it comprises the steps of milling a second tongue extending from the surface of a small face of a third panel shaped element and of milling a second groove on a fourth panel-shaped element; wherein the second tongue and second groove are configured for coupling by means of a locking tongue and groove connection the third panel-shaped element and the fourth panel-shaped element thereby forming a corner connection. The contour of the first tongue is substantially equal or equal to the contour of the second tongue; this substantially equal or equal tongue contour is called tongue contour. The profile of the first groove is substantially equal or equal to the profile of the second groove; wherein this substantially equal or equal groove profile is called groove. The thickness of the first panel-shaped element differs from the thickness of the third panel-shaped element and/or the thickness of the second panel-shaped element differs from the thickness of the fourth panel-shaped element.

It is a benefit of the method of the sixth aspect of the invention that the same sets of tools can be used to make tongues on the one hand and grooves on the other hand in panel-shaped elements with different thicknesses. It is a further benefit that the coupling of panel-shaped element of a certain thickness which is provided with a tongue to a panel-shaped element of another thickness which is provided with a groove is made possible. This is of interest e.g. when the composed element is assembled from panel-shaped elements of different thickness, e.g. outer panel-shaped elements having a different thickness compared to panel-shaped elements provided inside a cabinet. It is a further benefit that coupling is made easy.

With the contour of the tongue is meant the outer circumference of the tongue in cross sectional view. The contour of the tongue does not comprise a slit if such split would be present in the tongue.

A preferred embodiment of the sixth aspect of the invention is characterized in that the profile of the first tongue is substantially equal or equal to the profile of the second tongue; this substantially equal or equal tongue profile is called tongue. The profile of the tongue comprises the slit if a slit is present in the tongue.

A preferred embodiment of the sixth aspect of the invention is characterized in that the difference between the thickness of the first panel-shaped element and the thickness of third panel-shaped element is at least 2 mm; and/or in that the difference of the thickness of the second panel-shaped element and the thickness of the fourth panel-shaped element is at least 2 mm.

Preferably, each of the first panel-shaped element, the second panel-shaped element, the third panel-shaped element and the fourth panel-shaped element are between 12 and 18 mm thick.

A preferred embodiment of the sixth aspect of the invention is characterized in that the perpendicular distance from the distal end of the first tongue to a first surface of the first panel-shaped element is equal to the perpendicular distance from the distal end of the second tongue to a first surface of the third panel-shaped element. Such embodiments facilitate the coupling of the tongues into the grooves.

Preferably this perpendicular distance is less than 2 mm, more preferably less than 1.8 mm. Such embodiments facilitate the couplings of the tongues into the grooves even more.

A preferred embodiment of the sixth aspect of the invention is characterized in that the thickness of the first panel-shaped element is equal to the thickness of the third panel-shaped element and/or that the thickness of the second panel-shaped element is equal to the thickness of the fourth panel-shaped element. Such embodiments provide for composted elements that can be coupled nicely to show composed elements of high quality having a good looking appearance.

A preferred embodiment of the sixth aspect of the invention is characterized in that the groove is configured as the groove in any embodiment of the first, second, third, fourth or fifth aspect of the invention; and/or that the tongue contour is configured as the contour of the tongue in any embodiment of the first, second, third, fourth or fifth aspect of the invention; and/or that the tongue is configured as the tongue in any embodiment of the first, second, third, fourth or fifth aspect of the invention. Such embodiments are preferred as coupling of tongues and grooves of panel-shaped elements of different thickness is made easier.

Further characteristics of the invention will become clear from the description following below and the appended claims.

With the intention of better showing the characteristics of the invention, hereafter, as an example without any limitative character, some preferred embodiments are described, with reference to the accompanying drawings, wherein: figure 1 schematically represents a composed element according to the invention; figure 2, at a larger scale, represents a cross-section according to line II-II in figure 1; figure 3, at a larger scale, represents the part indicated by F3 in figure 2; figures 4 and 5 show two ways of realizing the connection of figure 3; figure 6 represents the part indicated by F6 in figure 5; figure 7 represents a particular embodiment of a coupling, showing the parts to be coupled; figure 8 represents a particular technique for realizing the groove represented in figure 7; figure 9 represents a view similar to that of figure 11, however, in coupled condition; and figure 10 illustrates an aspect of the invention.

The reference numerals have the same meaning in the different figures.

In figures 1 and 2, an example of a composed element 1 according to the invention is represented, in the form of a piece of furniture, more particularly a cabinet, which substantially is composed of panel-shaped elements 2a, 2b connected to each other at an angle. The panel-shaped elements, in the example, provide the right side wall 3, the bottom wall 4, the left side wall 5 and the top wall 6. This piece of furniture also comprises a skirting board 7, a back part 8 and two shelves 9, 10.

In the example shown, the first panel-shaped element 2a and the second panel-shaped element 2b are each 12 mm thick. Other thicknesses are possible, preferred are thickness between 12 and 18 mm.

As represented in the figures, the panel-shaped elements 2a, 2b preferably are formed of a covered board, with preferably on both sides a covering layer, 43 and 45, respectively. This preferably relates to a melaminated board, thus, a board which is provided with a laminate covering. In particular, the laminate layer can consist at least of a decor layer provided with resin and pressed on the board, whether or not in combination with other layers. Examples hereof are HPL (High Pressure Laminate) or DPL (Direct Pressure Laminate). Also, a film, lacquer layer or the like can be applied, or any other form of covering. The basic board itself preferably consists of MDF (Medium Density Fiberboard), HDF (High Density Fiberboard), plywood or particle board.

As will be clear from the different views of the figures 2 to 6, the respective panelshaped elements 2a, 2b comprise coupling zones in which coupling parts - tongues 15 and grooves 16 - are present. The coupling parts allow that each time two panelshaped elements 2a, 2b can be coupled to each other in a locking manner and at an angle, forming a comer connection. In the represented example, the coupling parts are provided as a split tongue 15, which cooperates with a groove 16.

As is illustrated in more detail in figures 2 - 6, the exemplary composed element 1 of figure 1 comprises a first 2a and a second 2b panel-shaped element, which, by means of a locking tongue and groove connection, can be coupled directly to each other thereby forming a corner connection. The connection comprises, at least at the first panel-shaped element 2a, a tongue 15, which can cooperate with a groove 16 provided on the second panel-shaped element 2b. The tongue 15 extends from the surface of a small face of the first panel-shaped element.

The tongue 15 comprises a tip 40 provided at the distal end of the tongue 15. The tip 40 has a tangent plane, called the first tangent plane 42. The tip 40 of the tongue 15 comprises a planar section 48, and the first tangent plane 42 is the tangent plane to the planar section 48 of the tip 40. The angle A5 between the first tangent plane 42 and the small face 19 of the first panel-shaped element 2a is 17° in the example shown.

The groove 16 comprises a bottom 44 provided by the deepest section of the groove 16. The bottom 44 has a tangent plane, called the second tangent plane 46. The bottom 44 of the groove 16 comprises a planar section 50, and the second tangent plane 46 is the tangent plane to the planar section 50 of the bottom 44 of the groove 16. In the example shown, the second tangent plane 46 is parallel with the surface of the second panel-shaped element 2b. The angle Al between the first tangent plane 42 and the second tangent plane 46 is in the example shown equal to 17°. In coupled condition the tip 40 of the tongue 15 is located at and opposes the bottom 44 of the groove 16.

The tongue 15 of the exemplary embodiment consists of a split tongue 15, with, thus, at least a first part 21 and a second part 22, as well as a slit 23 located there between. The thickness Ts of the slit of the exemplary split tongue is 1.5 mm. The slit 23 extends deeper than the surface of the small face 19 of first panel-shaped element 2a from which the tongue 15 extends. The first part 21 of the tongue 15 protrudes farther from the small face 19 of the first panel-shaped element 2a than the second part 22 of the tongue 15. The tip of the tongue 15 is provided in the first part 21 of the tongue 15.

The slit 23 is delimited by a first inner surface 24 of the tongue 15, a second inner surface 25 of the tongue 15 and a bottom 26. The first inner surface 24 and the second inner surface 25 are parallel with each other.

In the embodiment shown, the first inner surface 24 and the second inner surface 25 are not parallel with the large parallel surfaces 52, 54 defining the length and width of the first panel-shaped element 2a. The slit 23, globally seen, extends at an angle, with parallel first and second inner surfaces 24, 25.

The distance L4 with which the slit 23 extends from the small face 19 inwardly in the first panel-shaped element 2a is larger than the largest distance LI by which the tongue 15 reaches up to outward of the surface of the small face 19.

At one side of the groove 16 the transition section 56 between the surface 20 of the second panel-shaped element 2b and the groove 16 comprises at the bending section 58 a radius of curvature R which is the example shown equal to 1 mm.

The transition section 56 between the surface 20 of the second panel-shaped element 2b and the groove 16 comprises from the surface 20 of the second panel-shaped element 2b towards the groove 16 a first section 60, bending section 58 and a second section 62. The tangent plane to the first section 60 has an included angle A2 with the surface 20 of the second panel-shaped element which is larger than 130°, and preferably larger than 140° and preferably larger than 150°. In the example shown, this angle A2 is 152°.

The included angle A3 between the first tangent plane 42 and the tangent plane to the first section 60 is less than 30°, preferably less than 20° even more preferably less than 15°. In the example shown, the angle A3 is 15°.

The tangent plane to the second section 62 has an included angle A4 with the surface 20 of the second panel-shaped element 2b which is larger than 115°, and preferably larger than 120°, more preferably larger than 125°. In the example shown, this angle A4 is 127°.

The bending point of the center of the bending section 58 of transition section 56 is provided at a distance T2 of at least 0.75 mm, and preferably at a distance of at least 0.8 mm, from the surface 20 of the second panel-shaped element 2b. In the example shown, this distance is 0.83 mm.

The groove 16 comprises a first bottom 64 and a second bottom 66. The first bottom 64 is provided deeper than the second bottom 66. The transition section 56 is provided at the side of the groove 16 comprising the second bottom 66.

In coupled condition of the tongue 15 and the groove 16, the second part 22 of the tongue 15 is located at the side of the groove 16 comprising the transition section 56.

In coupled condition of the exemplary embodiment illustrated in the figures, the corner connection provides an inner comer 68 and an outer corner 70,. Contact is established at the outer corner between the surface 20 of the second panel-shaped element 2b and the small face 19 of the first panel-shaped element 2a. The planar surface of the small face 19 extends in the direction towards the tongue 19 beyond the planar surface of the second panel-shaped element 2b.

The tongue 15 and the groove 16 are configured such that they can be turned into each other, wherein the angle from which they can be turned into each other forms an inner corner 68.

The tongue 15 has a thickness Tt, measured at the surface of the small face 19 of the first panel-shaped element 2a from which the tongue 15 extends. The tip 40 of the tongue 15 is provided entirely in the bottom half of the thickness Tt of the tongue. The first tangent plane 42 is oriented from the bottom half of the tongue towards the upper half of the thickness of the tongue 15.

The tongue 15 extends further from the small face 19 at the bottom half of the thickness of the tongue 15 than at the upper half of the thickness of the tongue. In coupled condition the bottom half of the thickness Tt of the tongue 15 is situated closest to the inner corner 68. In the example shown, the thickness Tt of the tongue is 7.7 mm.

The tongue 15 is located eccentrically, in coupled condition in the direction of the inner corner 68 of the comer connection.

The tongue 15 comprises a first locking part 17 provided at the outer side of the first part 21 of the tongue 15. The second part 22 of the tongue 15 does not comprise a locking part. The first locking part 17 is provided for cooperation with a second locking part 18 provided in the groove 16. The cooperation of the first locking part 17 and the second locking part 18 prevent in coupled condition the drifting apart of the tongue 15 and groove 16. In the cooperation of the first locking part 17 and the second locking part 18, a pair of contact surfaces 36, 37 is formed between the first locking part 17 and the second locking part 18.

The tongue 15 is made in one piece with the first panel-shaped element 2a, and formed in the material itself, from a basic board with which the first panel-shaped element 2a is formed.

The groove 16 is made in one piece in the second panel-shaped element 2b, and formed in the material itself, from a basic board with which the second panel-shaped element 2b is formed.

The panel-shaped elements 2a, 2b can be joined together by means of a snap movement, by displacing the panel-shaped elements by means of a mutual translation movement S, as illustrated in figure 4. The tongue 15 fits into the groove 16 by means of a snap movement S, such by pressing the respective panel-shaped element 2a with the tongue 15 in its plane towards the groove 16. In the represented embodiment, this is achieved in that the locking part 17 can perform a lateral elastic movement, possibly in combination with a slight elastic compression in the material of the two locking parts 17, 18, and this locking part 17 in this manner can engage behind the locking part 18, this all whether or not combined with some more compression in the material of tongue 15 and groove 16.

The tongue 15 can also be fit into the groove 16 by means of a turning movement W, such as illustrated in figure 5, wherein the turned-in first panel-shaped element 2a, in right-angled condition, obtains its end position. The turning movement W takes place along the side of the inner corner 68 of the represented composed element 1. Releasing both panel-shaped elements 2a, 2b either takes place by a turning movement in opposite direction, or by pulling or tapping the panel-shaped elements out of each other in a direction parallel to the tongue.

Figures 7 - 9 illustrate an embodiment of the invention. The groove 16, seen in cross- sectional view, is completely symmetrical. As is diagrammatically represented in figure 8, such symmetrical groove 16 can be formed by a finger milling cutter 60.

An advantage of this technique is that it can be applied for applications wherein the groove 16 cannot be made continuously and, at least at one end, has to end in the material of the respective panel-shaped element.

An advantage of such symmetrical groove, irrespective whether it is made continuous or not continuous, is that at least the contour, and even the entire groove, can be realized in a single milling cycle, which is cost-saving.

Another advantage consists in that irrespective whether the locking has to take place at the left hand side or the right hand side in the groove, this groove always is the same. As no different grooves are necessary, in certain applications the manipulations necessary for realizing locking grooves can be simplified considerably.

Figure 10 illustrates an example of composed elements resulting from the use of a method according to the sixth aspect of the invention. Figure 10 shows - with the surfaces of one side of the panel-shaped elements superimposed onto each other - a first panel-shaped element 2al and a third panel-shaped element 2a2; and - with the surfaces of one side of the panel-shaped elements superimposed onto each other - a second panel-shaped element 2b 1 and a fourth panel-shaped element 2b2.

The first panel-shaped element 2al has thickness Tpl, e.g. 12 mm. The third panelshaped element 2a2 has thickness Tp2, which differs from the thickness Tpl of the first panel-shaped element lai. The thickness Tp2 of the third panel-shaped element 2a2 is e.g. 18 mm.

The second panel-shaped element 2bl has thickness Tql, e.g. 12 mm. The fourth panel-shaped element 2b2 has thickness Tq2, which differs from the thickness Tql of the second panel-shaped element 2b 1. The thickness Tq2 of the fourth panelshaped element 2a2 is e.g. 18 mm.

A tongue 15 has been milled extending from the surface of a small face 19 of the first panel-shaped element 2al. A groove 16 has been milled on the second panel-shaped element 2b 1. This tongue and groove are provided for coupling the first panel-shaped element 2al to the second panel-shaped element 2b 1 in the assembly of a composed element thereby forming a corner connection as shown in figure 10.

In the similar way, a tongue 15 has been milled extending from the surface of a small face 19 of the third panel-shaped element 2a2. A groove 16 has been milled on the fourth panel-shaped element 2b2. This tongue and groove are provided for coupling the third panel-shaped element 2a2 to the fourth panel-shaped element 2b2 in the assembly of a composed element thereby forming a corner connection as shown in figure 10.

In the example shown in figure 10, the profiles of the tongues 15 of the first panelshaped element 2al and of the third panel-shaped element 2a2 are equal, as is illustrated in figure 10 by the superposition of the first 2al and the third 2a2 panelshaped element. The profiles of the grooves of the second panel-shaped element 2b 1 and of the fourth panel-shaped element 2b2 are equal, as is illustrated in figure 10 by the superposition of second 2b 1 and fourth 2b2 panel-shaped element.

It means that the same tools can be used to mill the tongue of the first panel-shaped element 2al and the tongue of the third panel-shaped element 2a2. The same tools can be used to mill the groove of the second panel-shaped element 2b 1 and the fourth panel-shaped element 2b2. The tongues 15 and grooves 16 can be milled with tooling known to the skilled person.

The tongue 15 and/or the groove 16 can be configured as disclosed in any embodiments of the first, second, third, fourth or fifth aspect of the invention.

As the tongue 15 of the first 2al and the third 2a2 panel-shaped element have the same profile, and as the groove 16 of the second 2b 1 and the fourth 2b2 panel-shaped element have the same profile; it is also possible to couple the first 2al panel-shaped element to the fourth 2b2 panel-shaped element; and to couple the third 2a2 panelshaped element to the second 2b 1 panel-shaped element.

In the embodiment shown in figure 10, the perpendicular distance L5 from the distal end of the first tongue 15 to a first surface 54 of the first panel-shaped element 2al is equal to the perpendicular distance L5 from the distal end of the second tongue 15 to a first surface 54 of the third panel-shaped element 2a2. In the example shown, this perpendicular distance L5 is 1.8 mm.

The tongues 15 and grooves 16 - and the locking parts 17, 18 - in all mentioned aspects and examples preferably are made in one piece of the material of the panelshaped element in which they are provided. This may relate to any material. In most applications, however, use will be made of wood-based panels, with a wood-based substrate, such as MDF (Medium Density Fiberboard), HDF (High Density Fiberboard), plywood or particle board.

The present invention is in no way limited to the embodiments described by way of example and represented in the figures; on the contrary may such composed elements, and more particularly the parts thereof which provide for the realization of said aspects, be realized according to various variants without leaving the scope of the invention.