Panel, Covering, and Method of Uncoupling Two Interconnected Panels

Abstract

The present invention relates to a panel suitable as a floor, ceiling or wall panel, which panel is of a planar design having an upper side, a bottom side and side edges. Furthermore, the invention relates to a covering including a plurality of interconnected panels according to the invention. The invention also relates to a method of uncoupling two (or more) interconnected panels.

Claims

1. A panel suitable as a floor, ceiling or wall panel, which panel is of a planar design having an upper side, a bottom side and side edges which comprise a first side edge provided with a first profile and a second side edge provided with a second profile, wherein the first profile and the second profile are mutually interacting profiles that can be coupled to each other, so that a first panel can be coupled in one common plane to a second, identical panel by the mutually interacting profiles, wherein the first profile and the second profile in coupled condition establish an interlocking with each other both in a horizontal direction and in a vertical direction, and wherein the first profile and the second profile are configured to allow for: a coupling of the mutually interacting profiles of the first panel and the second panel by a vertical insertion of the mutually interacting profile of the second panel into the mutually interacting profile of the first panel, and an uncoupling of said mutually interacting profiles of the first panel and the second panel by a downward angling movement between the first panel and the second panel out of the common plane.

2. The panel according to claim 1, wherein the first profile and second profile are essentially complementary profiles.

3. The panel according to claim 1, wherein the first profile is provided along the first side edge of the panel, and comprises an upward tongue which is connected to the first side edge by a lower bridge part extending parallel to the plane of the panel at the bottom side of the panel, and wherein the lower bridge part delimits a upward groove which is enclosed between the upward tongue and the first side edge; and the second profile is provided along the second side edge of the panel, comprises a downward tongue which is connected to the second side edge by an upper bridge part extending parallel to the plane of the panel at a top side of the panel, and wherein the upper bridge part delimits an downward groove which is enclosed between the downward tongue and the second side edge; further wherein the first groove and the second groove are configured to receive respectively the downward tongue and the upward tongue when the respective mutually interacting profiles of two identical panels are coupled to each other.

4. The panel according to claim 3, wherein the surface of the upward tongue that borders on the downward groove, comprises an interlocking surface area which is angled upwards and towards the downward groove, preferably at an angle of 1 to 20 degrees with respect to an upward vertical vector of the panel, when measured in a vertical plane perpendicular to the side edge, and wherein the surface of the downward tongue that borders on the upward groove, comprises an interlocking surface area which is angled upwards and away from the upward groove, preferably at an angle of 1 to 20 degrees with respect to an upward vertical vector of the panel, when measured in a vertical plane perpendicular to the side edge, wherein, when the mutually interacting profiles of two identical panels are coupled to each other, the interlocking surface areas of the upward tongue and the downward tongue interact with each other such that a vertical interlocking is achieved.

5. The panel according to claim 4, wherein the interlocking surface areas of the downward tongue and the upward tongue are configured to be facing each other, preferably in abutting contact, when the first and second panel are in coupled condition.

6. The panel according to claim 4, wherein the interlocking surface areas are part of a curved surface of the downward tongue and the upward tongue, when viewed in a cross-sectional vertical plane perpendicular to the respective side edge.

7. The panel according to claim 6, wherein the curved surface of the downward tongue and the upward tongue has a convex form between the interlocking surface area and the top of the respective tongue, when viewed in a cross-sectional vertical plane perpendicular to the respective side edge.

8. The panel according to claim 6, wherein the curved surface of the downward tongue and the upward tongue, has a concave form between the interlocking surface area and the bottom of the corresponding downward groove and downward groove, when viewed in a cross-sectional vertical plane perpendicular to the respective side edge.

9. The panel according to claim 4, wherein at least one of the interlocking surface areas of the downward tongue and the upward tongue, and preferably the interlocking surface area of the downward tongue, is provided with a malleable coating, in particular a wax coating.

10. The panel according to claim 3, wherein an upper part of the first side edge of the first panel and an upper part of the downward tongue of the second side edge of the second panel comprise respective upper contact surfaces which are configured to be in abutting contact when the first and second panel are in coupled condition, which upper contact surfaces are substantially vertically oriented.

11. The panel according to claim 10, wherein at least one of the upper contact surfaces of the first panel and the second panel is provided with a malleable coating, in particular a wax coating.

12-17. (canceled)

18. The panel according to claim 1, wherein a frontal side of the upward tongue of the first profile is provided with at least one locking element, in particular a protrusion, and a horizontally opposed frontal side of the second profile is provided with a counterlocking element, in particular a recess, wherein the protrusion and the recess are substantially complementary, such that in a coupled condition of two panels, the locking element, in particular the protrusion, of the first profile and the counterlocking element, in particular the recess, of the second profile mutually interlock, and wherein the locking element and the counterlocking element define at least one pivot point or at least one pivot zone around which, in coupled condition of the panels, the panels can be mutually angled downwardly during uncoupling of said first profile and the second profile.

19. The panel according to claim 18, wherein an upper part of the first side edge comprises a first, preferably substantially vertical, upper contact surface, and wherein an upper part of an outer side of the downward tongue of the second profile defines a second, preferably substantially vertical, upper contact surface, which first and second contact surfaces are configured to be in abutting contact when a first and a second panel are in coupled condition, and preferably such that a substantially watertight seam is created between said panels.

20. The panel according to claim wherein, in a cross-section of the panel, in particular of the second profile, a first virtual line extending between the pivot point or pivot zone to a portion of the second upper contact surface defines a first radius of a first virtual angling out circle representative for the movement of the second profile with respect to the first profile during uncoupling, wherein at the intersection of said first virtual circle and the second upper contact surface portion an upwardly directed first tangent to said second upper contact surface portion points away from said first virtual circle.

21. The panel according to claim 18, wherein a frontal side of the upward tongue of the first profile is provided with at least one locking element, in particular a protrusion, and a horizontally opposed frontal side of the second profile is provided with a counterlocking element, in particular a recess, wherein the protrusion and the recess are substantially complementary, wherein the locking element comprises at least one locking surface, and wherein the counterlocking element comprises at least one counterlocking surface, such that in a coupled condition of two panels, the locking surface and the counterlocking surface are configured to co-act with each other to realize a locking effect in at least vertical direction, wherein the locking surface and the counterlocking surface are located at a level which is below a deepest point of an upward groove enclosed by the upward tongue and a core of the panel, wherein the pivot point or pivot zone is defined by the locking surface and counterlocking surface.

22. (canceled)

23. (canceled)

24. The panel according to claim 18, wherein, in a cross-section of the panel, in particular in a cross-section of two interconnected panels, a second virtual line extending between the pivot point or pivot zone to a portion of the second interlocking surface area defines a second radius of a second virtual angling out circle representative for the movement of the second profile with respect to the first profile during uncoupling, wherein the portion of the second interlocking surface area is chosen such that the second virtual circle intersects the upward tongue, and wherein at the intersection of said second virtual circle and the second interlocking surface area an upwardly directed second tangent to said second interlocking surface area points away from said second virtual circle.

25. The panel according to claim 24, wherein the portion of the second interlocking surface area is chosen such that the second virtual circle intersects an outer surface of the upward tongue at at least two distant points.

26. (canceled)

27. (canceled)

28. The panel according to claim 1, comprising a third side edge which is provided with an identical first profile as provided on the first side edge, and a fourth side edge which is provided with an identical second profile as provided on the second side edge.

29. The panel according to claim 1, wherein the panel comprises at least one third profile and at least one fourth profile arranged on another pair of opposite sides of the panel, wherein the third profile of said panel and the fourth profile of another panel are preferably arranged to be coupled by means of an angling down motion.

30. The panel according to claim 29, wherein the third coupling part comprises: a sideward tongue extending in a direction substantially parallel to the upper side of the core, at least one second downward flank lying at a distance from the sideward tongue, and a second downward groove formed between the sideward tongue and the second downward flank, and wherein the fourth coupling part comprises: a third groove configured for accommodating at least a part of the sideward tongue of the third coupling profile of an adjacent panel, said third groove being defined by an upper lip and a lower lip, wherein said lower lip is provided with an upward locking element, wherein the third coupling part and the fourth coupling part are configured such that two of such panels can be coupled to each other by means of a turning movement, wherein, in coupled condition: at least a part of the sideward tongue of a first panel is inserted into the third groove of an adjacent, second panel, and wherein at least a part of the upward locking element of said second panel is inserted into the second downward groove of said first panel.

31. The panel according to claim 1, wherein the panel is a decorative panel, comprising: at least one core layer, and at least one decorative top section, directly or indirectly affixed to said core layer, wherein the top section defines a top surface of the panel, a plurality of side edges at least partially defined by said core layer and/or by side top section, which at least two opposing side edges are provided with the first coupling part and the second coupling part, respectively.

32-34. (canceled)

35. A covering for a floor, ceiling or wall, which is constituted by a multitude of coupled panels according to claim 1.

36. A method of uncoupling two identical panels according to claim 1, which are coupled to each other in a common plane by two mutually interacting first and second profiles, the method comprising the step of uplifting of one of the two panels out of the common plane, during which uplifting the two mutually interacting first and second profiles accomplish a downward angling movement between the two panels out of the common plane.

37-40. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0097] The invention will be further elucidated with reference to preferred embodiments of the invention that are shown in the appended figures, wherein:

[0098] FIG. 1 shows in perspective a panel according to the invention;

[0099] FIG. 2 shows a cross-sectional view of two panels according to the invention;

[0100] FIG. 3 shows a cross-sectional view of two coupled panels that are uncoupled by an angling movement;

[0101] FIG. 4 shows in cross-section details of two mutually interacting profiles according to the invention;

[0102] FIG. 5 shows the two profiles of FIG. 4 in a coupled condition in a common plane;

[0103] FIG. 6 shows the two profiles of FIG. 4 that are uncoupled by an angling movement;

[0104] FIG. 7 shows the two profiles of FIG. 5 in a coupled condition in a common plane, wherein the profiles are analysed by means arrows, lines, and circles;

[0105] FIG. 8 shows the two profiles of FIG. 5 with various thicknesses and wherein the profiles are analysed by means arrows, lines, and circles;

[0106] FIG. 9 schematically shows two alternative interconnected panels with first and second coupling parts according to the present invention;

[0107] FIG. 10 schematically shows a first coupling part of a panel according to the present invention and FIG. 9; and

[0108] FIG. 11 schematically shows a second coupling part of a panel according to the present invention and FIG. 9.

DESCRIPTION OF THE INVENTION

[0109] FIG. 1 shows a panel 1 suitable as a floor, ceiling or wall panel, which panel is of a planar design having an upper side 7, a bottom side and side edges 3a-d which comprise a first side edge 3a provided with a first profile 10 and a second side edge 3c provided with a second profile 11.

[0110] FIG. 2 shows a cross-section of the panel 1 of FIG. 1, perpendicular to the first and second side edges 3a and 3c, which are provided with a first profile 10 and a second profile 11. The bottom side 9 of the panel 1, is laid on a substrate layer for instance a floor surface S. Another identical panel 1′ is shown in part, of which the second side edge 3c is to be coupled to the panel 1, by a downward vertical movement indicated by vector D.

[0111] The first profile 10 and the second profile 11 of both panels 1 and 1′ are mutually interacting profiles that can be coupled to each other. During coupling, the second profile 11 of panel 1′ is vertically inserted in the first profile 10 of panel 1, which involves the downward tongue 22 of panel 1′ being inserted in the first groove 23 of panel 1, and the upward tongue 21 of panel 1 being inserted in the second groove 24 of panel 1′. When coupled, the panels 1 and 1′ lie in a common plane which is parallel to the floor surface S.

[0112] FIG. 3 shows panels 1 and 1′ during a process of uncoupling according to the invention, after being coupled in accordance with the method shown in FIG. 2. By uplifting the panel 1 at the side edge 3a from the substrate layer along a vector U, the first profile 10 in cooperation with the second profile 11 of panel 1′ accomplish a hinging movement, so that panel 1′ makes a downward angling movement over an angle A out of the common plane P in which both panels were lying when in coupled condition. As such, a vertical extraction of second profile 11 from first profile 10 is no longer needed and can thus be avoided.

[0113] FIG. 4 shows in detail a preferred embodiment of the first profile 10 and second profile 11 provided at the first side edge 3a and the second side edge 3c, which is advantageously applied in a panel shown in the preceding FIGS. 1-3.

[0114] The first profile 10 comprises an upward tongue 21 which is connected to the first side edge 3a by a lower bridge part 40 extending parallel to the plane of the panel at the bottom side 9 of the panel, and wherein the lower bridge part 40 delimits a upward groove 23 is enclosed between the upward tongue 21 and the first side edge 3a, wherein the upward groove 23 has a bottom 41; and the second profile 11 comprises a downward tongue 22 which is connected to the second side edge 3c by an upper bridge part 42 extending parallel to the plane of the panel at a top side 7 of the panel, and wherein the upper bridge part 42 delimits an downward groove 24, which is enclosed between the downward tongue and the second side edge, wherein the downward groove 24 has a bottom 43.

[0115] The surface of the upward tongue 21 that borders on the upward groove 23, comprises an interlocking surface area 45 which is angled upwards and towards the upward groove 23 (as indicated by the respective dotted line), at an angle of 5 to 20 degrees with respect to an upward vertical vector V of the panel, when measured in a vertical plane perpendicular to the side edge 3a. The surface of the downward tongue 22 that borders on the downward groove 24, comprises an interlocking surface area 47 which is angled upwards and away from the downward groove (as indicated by the respective dotted line), at an angle of 5 to 20 degrees with respect to an upward vertical vector of the panel, when measured in a vertical plane perpendicular to the side edge 3c.

[0116] The curved surface of the upward tongue 22 and the downward tongue 23 has a convex form between the interlocking surface area 45 resp. 47, and the top 42 resp. 44 of the respective tongues, when viewed in a cross-sectional vertical plane perpendicular to the side edges 3a resp. 3c.

[0117] Furthermore, the curved surface the upward tongue 22 and the downward tongue 23 has a concave form between the interlocking surface area 45 resp. 47, and the bottom 41 resp. 43 of the respective upward groove 23 and downward groove 24, when viewed in a cross-sectional vertical plane perpendicular to the respective side edges 3a resp. 3c.

[0118] A frontal side 50 of the upward tongue 21 of the first profile 10 is provided with a protrusion 54, and a horizontally opposed frontal side 52 of the second profile 11 is provided with a recess 56, wherein the protrusion 54 and the recess 56 are substantially complementary, so that both mutually interlock in a coupled condition of two identical panels 1 and 1′. The first profile 10 and second profile 11 comprise upper contact surfaces 58 resp. 60, which provide for an abutting contact at the top side 7 in a coupled condition of two identical panels 1 and 1′.

[0119] The interlocking surface areas 45 and 47 are provided with a malleable coating 62 (thickness is exaggerated for clarity), such as a wax coating.

[0120] Further a first corner zone 64 connecting the frontal side 50 of the first side edge 3a with the bottom side 9 of the panel and a second corner zone 66 connecting a frontal side 52 of the second side edge with the bottom side 9 of the panel are bevelled. With respect to a downward vertical vector V′, the corner zones 64 and 66 are bevelled under an angle of 5 to 30 degrees, for instance 20 degrees such as depicted.

[0121] FIG. 5 shows first and second profiles 10 and 11, which are identical to those depicted in FIG. 4, and which are brought in a coupled condition that is achieved by coupling two identical panels 1 and 1′ as shown in FIG. 2. Identical features of the profiles that are shown in FIG. 4, are indicated by the same reference numerals.

[0122] The first profile 10 and the second profile 11 establish an interlocking with each other in a horizontal direction and in a vertical direction, by virtue of the cooperating tongues 21 and 22, the cooperating protrusion 54 and recess 56, and the upper contact surfaces 58, 60, wherein these pairs of cooperating features are in abutting contact with each other. Herein, the opposed interlocking surface areas 45 and 47 of the cooperating tongues 21 and 22 establish an the interlocking in vertical direction due to their angled orientation with respect to the upward vertical vector.

[0123] The first and second profiles 10 and 11 are essentially complementary, so that they are kept in a permanent position to each other because of the cooperating features described above. In addition, some opposing surface areas of the first and second profile 10 and 11 are not in abutting contact with each other, which allows for small interstitial spaces 70 between the two coupled profiles, which spaces 70 function as dust chambers.

[0124] By virtue of the bevelled corner zones 64 and 66, a void 68 is present at the interface of bottom sides 9 of two coupled panels, which void 68 has the form of a wedge having a wedge angle of about 40 degrees.

[0125] FIG. 6 shows the identical profiles 10 and 11 as shown in FIG. 5 of two identical panels 1 and 1′, which are uncoupled by an angling movement over an angle A, which uncoupling is more generally shown in FIG. 3.

[0126] In the stage of uncoupling shown, the angling movement dislodges the downward tongue 22 from the first upward groove 23, while the protrusion 54 and recess 56 remain in abutting contact and together function as a temporary hinge by which the angling movement is guided, when the panel 1 is uplifted along vector U. Consequently, the panel 1′ makes a downward angling movement over an angle A out of the common plane P in which both panels were lying when in coupled condition. By the angling movement the bevelled corner edges 64 and 66 are brought closer to each other, and hence the size of the wedge-formed void 68 between the two panels 1 and 1′ is reduced.

[0127] In a subsequent step, the panels 1 and 1′ may be completely uncoupled by a movement of panel 1′ in the common plane P away from panel 1, wherein the top 44 of the downward tongue 22 passes the top 42 of the upward tongue 21. Consequently, the protrusion 54 and recess 56 become dislodged as well, so that both the vertical and horizontal interlocking shown in FIG. 5 are dislodged, and the panels are uncoupled.

[0128] FIG. 7 is identical to FIG. 5, though wherein the profiles are analysed by means arrows, lines, and circles. In the shown cross-section, a first virtual line R1 extending between the pivot point P (or pivot zone) to a—or any—portion of the second upper contact surface 60 defines a first radius R1 of a first virtual angling out circle C1 representative for the movement of the second profile 10 with respect to the first profile 11 during uncoupling of these profiles 10, 11, wherein at the intersection 11 of said first virtual circle C1 and the second upper contact surface portion 60 an upwardly directed first tangent T1 to said second upper contact surface portion 60 points away from said first virtual circle C1, and (therefore) points away from a first circle tangent TC1 at said intersection 11. This allows a preferably entirely unhindered uncoupling of the contact surfaces 58, 60, since frictional contact between said contact surfaces 58, 60 can be kept to a minimum during uncoupling. What is further shown in FIG. 7 is a second virtual line R2 extending between the pivot point P (or pivot zone) to a—or any—portion of the second interlocking surface area 47 defines a second radius R2 of a second virtual angling out circle C2 representative for the movement of the second profile 10 with respect to the first profile 11 during uncoupling, wherein the portion of the second interlocking surface area 47 is chosen such that the second virtual circle C2 intersects the upward tongue 21, and wherein at the intersection 12 of said second virtual circle C2 and the second interlocking surface area 47 an upwardly directed second tangent T2 to said second interlocking surface area 47 points away from said second virtual circle C2. It is further shown that the portion of the second interlocking surface area 47 is chosen such that the second virtual circle C2 intersects an outer surface of the upward tongue at at least two distant points 12, 13. During uncoupling the second interlocking surface area 47 will have to be forced along the first interlocking surface area 45, which is typically realized by (temporary) deforming the second interlocking surface area 47 and/or the first interlocking surface area 45 during uncoupling. This prevents an easy, undesired uncoupling of the panels, which is in favour of the desired (horizontal and vertical) locking effect in interconnected condition of the panels.

[0129] FIG. 8 is quite similar to FIG. 7 and FIG. 5, panels with various panel thicknesses H1, H2, H3 are shown, and wherein for each panel thickness H1, H2, H3, the corresponding arrows, lines, and circles are shown which are also depicted in FIG. 7. The same reference signs and symbols which are used in FIG. 7 are also used in FIG. 8, but wherein are prefix “H1-”, “H2-”, and “H3-” is applied for the panels with thickness H1, H2, H3, respectively. In the panels with thickness H2, H3, the height and the shape of the upward groove 23 and the downward tongue 22 have been modified with respect to the original panel with thickness H1, which have been indicated by reference signs 22′, 23′ (for panel thickness H2) and 22″, 23″ (for panel thickness H3). The uncoupling mechanism for each panels thickness H1, H2, H3 is, however, similar.

[0130] The above-described inventive concepts are illustrated by several illustrative embodiments. It is conceivable that individual inventive concepts may be applied without, in so doing, also applying other details of the described example. It is not necessary to elaborate on examples of all conceivable combinations of the above-described inventive concepts, as a person skilled in the art will understand numerous inventive concepts can be (re)combined in order to arrive at a specific application. As shown with dashed lines, a top section of the upper contact surfaces 58, 60 of the panel (irrespective of the panel thickness) may be provided with a cut-out portion to form a bevel 80 (or grout).

[0131] FIG. 9 shows a floor panel 101, comprising a first coupling part 102 and a second coupling part 103 in coupled condition. The first coupling part 102 comprises an upward tongue 104, an upward flank 105 lying at a distance from the upward tongue 104 and an upward groove 106 formed in between the upward tongue 104 and the upward flank 105, wherein the upward groove 106 adapted the downward tongue 107 of a second coupling part 103 of another panel 101. The side of the upward tongue 104 facing towards the upward flank is the inside 108 of the upward tongue 104 and the side of the upward tongue 104 facing away from the upward flank 105 is the outside 109 of the upward tongue 104. The second coupling part 103 comprises a downward tongue 107, a downward flank 110 lying at a distance from the downward tongue 107, and a downward groove 111 formed in between the downward tongue 107 and the downward flank 110. The side of the downward tongue 107 facing towards the downward flank 110 is the inside 112 of the downward tongue 107 and the side of the downward tongue 107 facing away from the downward flank 110 is the outside 113 of the downward tongue 107. The outside 113 of the downward tongue 107 and the upward flank 105 both comprise an upper contact surface 114 at the top of the panel 101, which upper contact surfaces 114 are in contact extend vertically. Adjoining the upper contact surfaces 114 both the downward tongue 107 and the upward flank 105 comprise an inclined contact surface 115, which inclined contact surfaces 115 are in contact, wherein the upper contact surfaces 114 on the one hand, and the inclined contact surfaces 115 of the upward flank 105 and/or the outside 113 of the downward tongue 107 on the other hand preferably mutually enclose an angle α of approximately 125 degrees. The upper contact surface 114 and the inclined contact surface 115 of the upward flank 105 mutually enclose a first angle of about 125 degrees, and the upper contact surface 114 and the inclined contact surface 115 of the downward tongue 107 mutually enclose a second angle of about 125 degrees.

[0132] Adjoining the inclined contact surface 115 the downward tongue 107 comprises an outer surface 116, and adjoining the inclined contact surface 115 the upward flank 105 comprises an inner surface 117, wherein the outer 116 and inner 117 surface are parallel and vertical. Between the outer surface 116 and the inner surface 117 a space 118 is present. The upper contact surfaces 114 define an inner vertical plane 119, wherein the inclined contact surface 115 of the downward tongue 107 extends beyond the inner vertical plane 119 the inclined contact surface 115 of the upward flank 105 lies inward compared to the inner vertical plane 119. A portion 120 of the downward tongue 107 extends beyond the inner vertical plane 119, wherein said portion 120 is substantially trapezium-shaped or wedge-shaped. The inclined contact surfaces 115 are both arranged completely outside and adjoining the inner vertical plane 119. The portion 120 is elongated with a larger vertical portion compared to the horizontal portion. The bottom 121 of the downward tongue 107 contacts the upper side 122 of the upward groove 106 at a groove contact surface 123, wherein a gap 124 is present between the first 102 and second 103 coupling parts, extending from the inclined contact surfaces 115 to the groove contact surface 123. Additionally the upper surface 125 of the upward tongue 104 and the upper surface 126 of the downward groove 111, are distanced from each other such that a gap 127 is present between the two surfaces 125, 126. The outside 109 of the upward tongue 104 comprises a first locking element 128, in the form of an outward bulge and the downward flank 110 is provided with a second locking element 129, in the form of a recess, wherein the first 128 and at least a part of second 129 locking element are in contact, and form a locking element surface 130. The panels 101 can be coupled by means of a drop-down motion (vertical movement) visualized by arrow A and may also be coupled by means of a angling in movement (rotary movement) visualized by arrow B and can be uncoupled by means of an angling out movement, as (also) visualized by arrow B.

[0133] FIGS. 10 and 11 show the first and second coupling parts individually. The outside of the outward bulge 128 comprises an upper portion 131 and an adjoining lower portion 132, wherein the lower portion 132 comprises an inclined locking surface 130a and the upper portion 131 comprises a curved, guiding surface 132. The recess 129 comprises an upper portion 133 and an adjoining lower portion 134, wherein the lower portion comprises an inclined locking surface 130B. The upper portion 131, 133 extends over a larger vertical section compared to the lower portion 132, 134. The parts of the first 128 and second 129 locking element that are in contact are the inclined locking surfaces 130, 130A, 130B of the locking elements 128, 129 and the upper portions 131, 133 of the first 128 and second 129 locking elements are spaced apart at least partially. The outside 109 of the upward tongue 107 comprises an upper outside portion 135, and a lower outside portion 136, wherein the first locking element 128 is arranged between the upper 135 and lower outside portion 136. The lower outside portion 136 is arranged closer to the inside 108 of the upward tongue 104 compared to the upper outside portion 135. The upper outside portion 135 is substantially vertical and defines an outer vertical plane 137, wherein the first locking element 128 protrudes from the outer vertical plane 137. The lower outside portion 136 is substantially vertical and the inclined locking surface 130A or the lower portion 132 and the lower outside portion 136 enclose an angle β between 100 and 175 degrees. The angle α enclosed by the upper contact surfaces and the inclined contact surfaces and the angle β enclosed by the lower outside portion 136 and the inclined locking surface 130A or the lower portion 132 is about the same. An outermost portion 138 of the first locking element 128 and the locking surface 130a are arranged at a horizontal level which is lower compared to the upward groove 106. The same applies to the inclined counterlocking surface 130B of the recess 129.

[0134] The above-described inventive concepts are illustrated by several illustrative embodiments. It is conceivable that individual inventive concepts may be applied without, in so doing, also applying other details of the described example. It is not necessary to elaborate on examples of all conceivable combinations of the above-described inventive concepts, as a person skilled in the art will understand numerous inventive concepts can be (re)combined in order to arrive at a specific application.

[0135] By “complementary” coupling profiles or elements thereof is meant that these coupling profiles or elements can cooperate with each other. However, to this end, the complementary coupling profiles or elements do not necessarily have to have complementary shapes.

[0136] The verb “comprise” and conjugations thereof used in this patent publication are understood to mean not only “comprise”, but are also understood to mean the phrases “contain”, “substantially consist of”, “formed by” and conjugations thereof.