Mechanical locking system for building panels

Abstract

Panels are shown, which are provided with a mechanical locking system including a separate and flexible tongue allowing connection with a snap action. An outer edge part of the separate flexible tongue includes a guiding protrusion for disassembly of the panels and that is deformed during locking and/or unlocking.

Claims

1. A set of panels comprising a first panel and a second panel, a panel edge of the second panel being insertable into a core groove of the first panel to obtain a mechanical connection between the first panel and the second panel, the panel edge being insertable into the core groove by an essentially linear relative displacement of the first panel and second panel when the first panel and the second panel are arranged essentially perpendicularly to each other, said panel edge comprising a separate and flexible tongue and said core groove comprising a tongue groove, or said panel edge comprising a tongue groove and said core groove comprising a separate and flexible tongue, wherein the separate and flexible tongue is insertable into the tongue groove for connecting said panels to each other in a first direction, which is perpendicular to a main plane of the first panel, wherein the panel edge of the second panel is configured to cooperate with the core groove of the first panel for connecting said panels to each other in a second direction, which is perpendicular to a main plane of the second panel, wherein a longitudinal direction of the separate and flexible tongue extends from one short edge of the separate and flexible tongue to another short edge of the separate and flexible tongue, in a direction parallel with said panel edge and/or core groove, wherein the separate and flexible tongue is arranged in an insertion groove, said separate and flexible tongue being displaceable, perpendicularly to the longitudinal direction of the separate and flexible tongue, inwardly towards a bottom of the insertion groove and outwardly into the tongue groove during a locking of the first and second panels, and wherein the separate and flexible tongue comprises a guiding protrusion at the one short edge of the separate and flexible tongue.

2. The set of panels as claimed in claim 1, wherein the guiding protrusion comprises at least one straight portion.

3. The set of panels as claimed in claim 2, wherein, as seen from a top view, each straight portion is inclined with respect to a longitudinal direction of the tongue.

4. The set of panels as claimed in claim 1, wherein the guiding protrusion comprises at least two straight portions.

5. The set of panels as claimed in claim 4, wherein the straight portions are juxtaposed.

6. The set of panels as claimed in claim 4, wherein angles with respect to the longitudinal direction of the separate and flexible tongue are different between the different straight portions.

7. The set of panels as claimed in claim 6, wherein the angle increases by each straight portion towards the tip of the guiding protrusion.

8. The set of panels as claimed claim 1, wherein the guiding protrusion is curved about an axis transversal to the longitudinal direction of the tongue.

9. The set of panels as claimed in claim 1, wherein the guiding protrusion is configured such that its shape changes during the locking and/or unlocking of the first and second panels.

10. The set of panels as claimed in claim 1, wherein the guiding protrusion is further configured to be in contact with an inner part of the insertion groove during the locking.

11. The set of panels as claimed in claim 1, wherein there is a space between an inner part of the insertion groove and the guiding protrusion in a locked position of the first panel and the second panel.

12. The set of panels as claimed claim 1, wherein the guiding protrusion is configured to guide a rod shaped tool into the tongue groove when the rod shaped tool is inserted, along the longitudinal direction, into the insertion groove.

13. The set of panels as claimed in claim 12, wherein the rod shaped tool comprises an essentially round cross section.

14. The set of panels as claimed in claim 1, wherein the separate and flexible tongue comprises several flexible protrusions extending in the length direction of the tongue.

15. The set of panels as claimed in claim 1, wherein, when said panel edge comprises the tongue groove and said core groove comprises the separate and flexible tongue, said tongue groove is arranged in a lower side or in an upper side of the second panel.

16. The set of panels as claimed in claim 1, wherein, when said panel edge comprises the tongue groove and said core groove comprises the separate and flexible tongue, said insertion groove is formed in said core groove of the first panel.

17. The set of panels according to claim 16, wherein said insertion groove is arranged in a side wall of said core groove.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1a-1d illustrate known technology;

(2) FIGS. 2a-2d illustrate disassembly of locked panels according to an embodiment;

(3) FIGS. 3a-3d illustrate embodiments of separate flexible tongues;

(4) FIGS. 4a-4c illustrate assembly and disassembly of panels according to an alternative embodiment;

(5) FIGS. 5a-5d illustrate assembly and disassembly of panels located in the same main plane according to an embodiment.

DESCRIPTION OF EMBODIMENTS

(6) To facilitate understanding, several locking systems in the figures are shown schematically. It should be emphasised that improved or different functions can be achieved using combinations of the preferred embodiments.

(7) FIGS. 2a-d illustrate a first panel 1 and a second panel 2 which are connected to each other in accordance with an embodiment. The first panel 1 comprises a core groove 6 which is arranged in an upper side 1b of the first panel 1. The core groove 6 comprises two opposing side walls 6a, 6b and a bottom wall 6c. The opposing side walls 6a, 6b are parallel. The second panel 2 comprises a panel edge 12 which in a locked position of the panels 1, 2 is arranged in the core groove 6. More specifically, a portion of a lower side 2a, a portion of an upper side 2b, and a side edge 2c of the second panel 2 are arranged in the core groove 6. The panels 1, 2 may be locked to each other by means of a separate and flexible tongue 3.

(8) FIG. 2a shows a top view of the flexible tongue 3 in a locked position. A part of the flexible tongue 3 comprising flexible protrusions 8 is located in an insertion groove 4. An opposite part is located in the tongue groove 5 according to known technology. The flexible tongue 3 comprises an outer edge part 3a that is formed as a guiding protrusion 10 that automatically guides a rod shaped tool 9 into a tongue groove 5 when the tool 9 is inserted sideways into the insertion groove 4. The guiding protrusion 10 is arranged at a short edge of the tongue 3. It is understood that there may be a corresponding guiding protrusion 10 arranged at the other short edge of the tongue 3 (not shown).

(9) FIG. 2b shows that the flexible guiding protrusion is deformed when the rod shaped tool 9 is displaced sideways parallel to the length direction of the tongue 3 such that the tongue 3 is pressed into the insertion groove 4. It is an advantage if the flexible guiding protrusion 10 is in contact with an inner part of the insertion groove 4 during locking and when the tongue is pressed into the insertion groove. The guiding protrusion 10 is preferably flexible and is preferably also formed as a curved edge part.

(10) FIG. 2c shows a side view of the locking system. According to the present embodiment, a main plane MP-1 of the first panel 1 coincides with the upper side 1b of the first panel 1. Moreover, a main plane MP-2 of the second panel 2 coincides with the lower side 2a of the first panel 2, which is situated to the left, as shown in FIG. 2c. The rod shaped tool 9 preferably comprises an essentially round cross section. According to the present embodiment, the cross section of the rod shaped tool 9 is circular. Moreover, a width of the rod shaped tool 9 corresponds to a width of the tongue groove 5 between two parallel side walls 5a, 5b thereof. According to the present embodiment, a bottom wall 5c of the tongue groove 5, connecting the two side walls, is rounded. The curvature of the rounded bottom wall 5c substantially corresponds to the curvature of the rod shaped tool 9. Thereby, an improved guiding of the rod shaped tool 9 may be provided. In the present embodiment, the rod shaped tool 9 is adapted to be fitted inside the tongue groove 5 so that essentially no portion of the rod shaped tool 9 extends outside the lower side 2a of the second panel 2. Thereby, the panels 1, 2 may be easily disassembled, since the rod shaped tool 9 may be fitted inside the tongue groove 5 while the tongue 3 is displaced into the insertion groove 4, thereby releasing the mechanical connection between the first 1 and the second panel 2. FIG. 2d shows disassembly of the first 1 and the second panel 2 according to the present embodiment.

(11) It is clear that other shapes of the rod shaped tool 9 and the tongue groove 5 are equally conceivable. For example, the cross-section of the rod shaped tool 9 may be shaped as a polygon, a rectangle, a square, an oval, a triangle or a star. Additionally, according to alternative embodiments, the shape of the bottom wall may not correspond to the shape of the rod shaped tool 9. For example, the cross-section of the rod shaped tool 9 may be circular and the cross-section of the tongue groove 5 may be U-shaped, for example comprising a planar bottom wall.

(12) The insertion groove 4 may also be formed in the second panel 2 and the tongue groove 5 may be formed in the core groove 6 of the first panel 1. This will be described in more detail below.

(13) The above-described embodiment provides the advantages that the insertion of the tool 9 may be made into the whole cross section comprising the insertion groove 4 and the tongue grooves 5. A symmetric tool cross section may be used that eliminates a precise orientation of the tool 9 prior to insertion into the grooves.

(14) The guiding of the rod shaped tool 9 is illustrated in FIG. 2a and FIG. 2c. The broken lines illustrate the position of the rod shaped tool 9 when inserted into the insertion groove 4 and the arrows indicate that the rod shaped tool 9 is guided into the tongue groove 5 in the shown direction.

(15) FIG. 3a shows a tongue blank 11 comprising several thermoplastic injection-moulded flexible tongues 3. The tongues are preferably separated from the blank 11 at a separation portion S located inwardly and at a distance from the outer edge of the tongue 3.

(16) FIG. 3b shows that the guiding protrusion 10 may replace one of the flexible protrusions 8 such that all flexible protrusions 8 are located along the tongue in the length direction of the tongue and spaced in the length direction from the guiding protrusion 10.

(17) FIG. 3c shows that the principles of the invention may be used to improve disassembly when other types of tongues are used for example flexible tongues comprising a snap tab 13 at the outer part. The locking system comprising a flexible snap tab 13 may be formed such that a tool 9 with an essentially round cross section may be used to release the first 1 and the second 2 panels.

(18) FIG. 3d shows that such tongue 3 comprising a snap tab 13 may comprise a symmetric cross section in inner parts and an edge portion that may be cut or formed to a wedge shaped edge part 14. The flexible tongue may comprise a flexible snap tab and an asymmetric cross section along its length direction.

(19) In particular, the flexible tongue 3 may be tapering towards an edge of the flexible tongue 3 in a longitudinal direction. Thereby, an area of the cross section of the flexible tongue 3 may decrease towards the edge. Additionally, a maximal horizontal distance from an inner part of the cross section to an outer part of the cross section may decrease towards the edge. Here, the horizontal distance is measured in a direction along which the flexible tongue 3 is adapted to contract and expand. For example, the horizontal distance may be measured in a direction along which the flexible snap tab 13 is adapted to contract and expand. As shown in the embodiment according to FIG. 3d, the cross section of the flexible snap tab 13 decreases towards the edge. A portion 13a of the flexible snap tab 13 has been cut out from the flexible tongue 3 for providing the tapering edge.

(20) Next, an alternative embodiment will be described with respect to FIGS. 4a-c. FIGS. 4a and 4b show a side view of a first panel 1 and a second panel 2 which are being assembled. It is understood that, in FIGS. 4a-c, the first panel 1 extends horizontally and that the second panel 2 extends vertically and that only a connecting region of the first 1 and second 2 panel is shown. The first 1 and second 2 panels are arranged essentially perpendicularly to each other.

(21) According to the present embodiment, the first panel 1 comprises three parts: an upper part 30, a center part 32, and a lower part 34. The upper part 30 and the lower part 34 are located close to the upper 1b and lower 1a sides, respectively, and have a higher density than the center part 32.

(22) The core groove 6 comprises two opposing side walls 6a, 6b and a bottom wall 6c. The core groove 6 comprises a tongue groove 5. The tongue groove 5 is provided in the side wall 6a of the tongue groove 5. Thus, the tongue groove 5 is provided in a left part 21a of the first panel 1 which is located to the left of core groove 6. Moreover, the tongue groove 5 comprises two parallel side walls 5a, 5b and a bottom wall 5c. As seen from the side view in FIGS. 4a-c, a linear extension E of the lower side wall 5a is located at or above a right part 21b of the first panel 1, which is located to the right of core groove 6. Thereby, a tool, such as a cutting tool, may easily provide the tongue groove 5 by means of a linear displacement of the tool.

(23) An engagement portion 20 of the core groove 6 is bevelled. The bevelled engagement portion 20 is provided between an upper part of the side wall 6a and the upper side 1b of the first panel 1, thereby joining them. Alternatively, the engagement portion 20 of the core groove 6 may be rounded off.

(24) Moreover, the panel edge 12 of the second panel 2 has a smaller thickness than an inner part of the second panel 2, wherein the inner part is located farther from a side edge 2c of the second panel 2 than the panel edge 12. More specifically, the panel edge 12 comprises a lower edge side 22a and an upper side edge 22b which are parallel to each other and are located closer to the side edge 2c of the second panel 2 than a lower side 2a and an upper side 2b of the second panel 2. As displayed in FIG. 4c, the distance d.sub.1 between the lower edge side 22a and the upper side edge 22b is smaller than the distance d.sub.2 between the lower side 2a and the upper side 2b.

(25) The lower edge side 22a is joined to the lower side 2a by means of an overlapping portion 24. According to the present embodiment, there is a corresponding upper edge side 22b which is joined to the upper side 2b of the second panel 2 by means of an overlapping portion 25. By means of the overlapping portions 24, 25, which in an assembled state, or locked position, of the first 1 and second 2 panels engage with the bevelled engagement portion 20 and a bevelled surface 27 of the core groove 6, respectively, the panel edge 12 and/or the core groove 6 may be concealed in an improved manner.

(26) The panel edge 12 comprises a separate and flexible tongue 3. The separate and flexible tongue 3 may assume a contracted state and an expanded state and has a tendency to assume the expanded state when no forces are acting on it. The separate and flexible tongue 3 is arranged in an insertion groove 4 which is provided in lower edge side 22a of the panel edge 12. The separate and flexible tongue 3 comprises a chamfered portion 23 which is pointing downwards when the separate and flexible tongue 3 is inserted into the insertion groove 4.

(27) When the first 1 and second 2 panels are assembled, the panel edge 12 of the second panel 2 is inserted into the core groove 6 of the first panel 1 by a relative vertical displacement of the first 1 and second 2 panels. The displacement is linear. The separate and flexible tongue 3 is partly inserted into the insertion groove 4 and is further displaced into the insertion groove 4 when the chamfered portion 23 engages with the bevelled engagement portion 20 during the vertical displacement. By means of the bevelled engagement portion 20, the chamfered portion 23 engages with a smooth surface during the assembly. Thereby, the chamfered portion 23 may avoid engaging with any sharp edges during assembly. When displaced further into the insertion groove 4, the separate and flexible tongue 3 may become contracted. When the side walls 4a, 4b of the insertion groove 4 are aligned with the side walls 5a, 5b of the tongue groove 5, the separate and flexible tongue 3 may expand and may be displaced out from the insertion groove 4 and into the tongue groove 5 for obtaining a locking of the first 1 and second 2 panels in a direction which is perpendicular to the main plane MP-1 of the first panel.

(28) The core groove 6 comprises an inclined portion 16 between the side wall 6a and the bottom wall 6c as well as between the side wall 6b and the bottom wall 6c. Moreover, the panel edge 12 comprises a bevel 26 between the lower edge side 22a and the side edge 2c of the second panel 2 and a bevel 26 between the upper edge side 22b and the side edge 2c of the second panel 2. A shape of the inclined portion 16 may substantially correspond to a shape of the bevel 26. For example, the inclination of the inclined portion 16 and the bevel 26 may be substantially the same. The bevels 26 may remove sharp corners between the edge sides 22a, 22b and the side edge 2c. Moreover, the bevels 26 may guide the second panel 2 into a proper locking position.

(29) In a locked position of the panels 1, 2, the panel edge 12 cooperates with the core groove 6 for connecting the panels to each other in a second direction, which is perpendicular to a main plane MP-2 of the second panel 2.

(30) From FIG. 4b it is clear that the visible outer parts of the first 1 and second 2 panels have a uniform thickness in a locked position of the first 1 and second 2 panel.

(31) It is understood that according to an alternative embodiment, the second panel 2 may have a uniform thickness.

(32) FIG. 4c shows a side view of a first panel 1 and a second panel 2 which are being disassembled. This is analogous to the disassembly described above in relation to FIGS. 2a-d. In particular, when disassembling, the rod shaped tool 9 is inserted sideways into the insertion groove 4 and is guided into a proper position in the tongue groove 5 by means of a guiding protrusion 10 which is provided at a short edge of the separate and flexible tongue 3. When the rod shaped tool 9 is inserted into the tongue groove 5, the separate and flexible tongue 3 is displaced into insertion groove 4. Thereby, the second panel 2 becomes unlocked and the panel edge 12 may be removed from the core groove 6 by a relative linear vertical displacement of the first 1 and second 2 panel.

(33) FIGS. 5a-5d show a locking system that may be used to lock and unlock a first 1 and a second 2 panel that, in a locked position, are located in the same main plane MP-1. In other words, the panels are arranged essentially in parallel with each other. Such a locking system may be used to lock two or several furniture components with, for example, a length of 0.6 m and that after locking form a part of a book shelf with a length of, for example, 1.2 or 1.8 m. An advantage of providing this type of locking system is that smaller components are easier to transport, assemble and disassemble. It is clear than other lengths of the furniture components are equally conceivable. In non-limiting examples, the length may be between 0.1 m and 1.0 m.

(34) In the present embodiment, the first panel 1 and the second panel 2 have a uniform thickness.

(35) The first panel 1 comprises a core groove 6 and a tongue groove 5 and the second panel 2 comprises a panel edge 12 that is insertable into the core groove 6 with a displacement parallel with the main plane MP-1 of the first and the second panel. The panel edge 12 comprises a separate and flexible tongue 3 which is provided in an insertion groove 4. In a locked position of the panels, the separate and flexible tongue 3 locks into the tongue groove 5.

(36) According to an alternative embodiment (not shown), the tongue groove 5 may be provided in the second panel 2 and the separate and flexible tongue 3 may be provided in the first panel 1.

(37) It is essential that the locking system is strong in order to provide sufficient rigidity to the locked components. Preferably, an upper edge 30a and a lower edge 31a of the first panel 1 and an upper edge 31b and a lower edge 31b of the second panel 2 are in contact with each other when the panels 1, 2 are locked.

(38) According to the present embodiment, a side face of the panel edge 12 engages with a bottom wall of the core groove 6 in a locked position of the first 1 and second 2 panel. This may be seen in FIG. 5c. In addition, in a locked position, an upper and a lower face of the panel edge 12 engage with a respective one of two opposing side walls of the core groove 6. According to an alternative embodiment (not shown), however, the side face of the panel edge 12 may be separated from the bottom wall of the core groove 6 in a locked position of the first 1 and second 2 panel.

(39) The first panel 1 comprises an engagement portion 40 which is arranged to engage with the separate and flexible tongue 3 during locking of the first 1 and second 2 panel for displacing the separate and flexible tongue 3 inwardly towards the bottom of the insertion groove 4. The engagement portion 40 is inclined with respect to the main plane MP-1 of the first 1 and second 2 panel. Moreover, the engagement portion 40 is bevelled at a portion 42 which is adjacent to the tongue groove 5.

(40) FIG. 5d shows unlocking of the first 1 and second 2 panels with a rod shaped tool 9 according to the above-described methods. The separate and flexible tongue 3 comprises an outer edge part 3a that is formed as a guiding protrusion 10 that automatically guides the rod shaped tool 9 into the tongue groove 5 when the tool 9 is inserted sideways into the insertion groove 4.

EMBODIMENTS

(41) 1. A set of panels (1,2) comprising a first (1) and a second panel (2), a panel edge (12) of the second panel (2) being insertable into a core groove (6) of the first panel (1) to obtain a mechanical connection between the first and the second panel, the panel edge (12) being insertable into the core groove (6) by an essentially linear relative displacement of the first and second panel when the first and second panel are arranged essentially perpendicularly to each other, said panel edge (12) comprising a separate and flexible tongue (3) and said core groove (6) comprising a tongue groove (5), or said panel edge (12) comprising a tongue groove (5) and said core groove (6) comprising a separate and flexible tongue (3), wherein the separate and flexible tongue (3) is insertable into the tongue groove (5) for connecting said panels to each other in a first direction, which is perpendicular to a main plane (MP-1) of the first panel, wherein the panel edge (12) of the second panel (2) is configured to cooperate with the core groove (6) of the first panel (1) for connecting said panels to each other in a second direction, which is perpendicular to a main plane (MP-2) of the second panel, wherein a longitudinal direction of the separate and flexible tongue (3) extends parallel with said panel edge and/or core groove, and wherein the separate and flexible tongue (3) is arranged in an insertion groove (4), said separate and flexible tongue (3) being displaceable inwardly towards a bottom of the insertion groove (4) and outwardly into the tongue groove (5) during a locking of the first and second panel, characterized in that the separate and flexible tongue (3) comprises a guiding protrusion (10) at a short edge of the separate and flexible tongue (3), and that the guiding protrusion (10) is configured such that its shape changes during the locking and/or unlocking of the first and second panel.

(42) 2. The set of panels as in embodiment 1, wherein the guiding protrusion (10) is further configured to be in contact with an inner part of the insertion groove (4) during the locking.

(43) 3. The set of panels as in embodiment 1, wherein there is a space between an inner part of the insertion groove (4) and the guiding protrusion (10) in a locked position of the first (1) and the second (2) panel.

(44) 4. The set of panels as in any of the preceding embodiments, wherein the guiding protrusion (10) is curve shaped and configured to guide a rod shaped tool (9) into the tongue groove (5) when the rod shaped tool (9) is inserted into the insertion groove (4).

(45) 5. The set of panels as in any of the preceding embodiments, wherein the rod shaped tool (9) comprises an essentially round cross section.

(46) 6. The set of panels as in any of the preceding embodiments, wherein the separate and flexible tongue (3) comprises several flexible protrusions (8, 10) extending in the length direction of the tongue (3).

(47) 7. The set of panels as in any of the preceding embodiments, wherein, when said panel edge (12) comprises the tongue groove (5) and said core groove (6) comprises the separate and flexible tongue (3), said tongue groove (5) is arranged in a lower side (2a) or in an upper side (2b) of the second panel (2).

(48) 8. The set of panels as in any of the preceding embodiments, wherein, when said panel edge (12) comprises the tongue groove (5) and said core groove (6) comprises the separate and flexible tongue (3), said insertion groove (4) is formed in said core groove (6) of the first panel (1).

(49) 9. The set of panels according to embodiment 8, wherein said insertion groove (4) is arranged in a side wall (6a) of said core groove (6).

(50) 10. A locking system for locking of panels (1, 2) comprising a first (1) and a second panel (2), wherein a panel edge (12) of the second panel (2) is insertable into a core groove (6) of the first panel (1) to obtain a mechanical connection between the first and the second panel, the panel edge (12) being insertable into the core groove (6) by an essentially linear relative displacement of the first and second panel when the first and second panel are arranged essentially perpendicularly to each other, wherein the locking system comprises: a separate and flexible tongue (3) arranged in an insertion groove (4) which is formed in the core groove (6); and a tongue groove (5) at the panel edge (12), said tongue groove (5) being adapted to accommodate a part of the separate and flexible tongue (3), characterized in that the separate and flexible tongue (3) comprises a guiding protrusion (10) at a short edge of the separate and flexible tongue (3), and that the guiding protrusion is configured such that its shape changes when a rod shaped tool (9) is inserted into at least a part of the tongue groove (5).

(51) 11. A locking system as in embodiment 10, wherein the rod shaped tool (9) comprises an essentially round cross section.

(52) 12. A set of panels (1,2) comprising a first (1) and a second panel (2), a panel edge (12) of the second panel (2) being insertable into a core groove (6) of the first panel (1) to obtain a mechanical connection between the first and the second panel, the panel edge (12) being insertable into the core groove (6) by an essentially linear relative displacement of the first and second panel when the first and second panel are arranged essentially perpendicularly to each other, said panel edge (12) comprising a separate and flexible tongue (3) and said core groove (6) comprising a tongue groove (5), wherein the separate and flexible tongue (3) is insertable into the tongue groove (5) for connecting said panels to each other in a first direction, which is perpendicular to a main plane (MP-1) of the first panel, wherein the panel edge (12) of the second panel (2) is configured to cooperate with the core groove (6) of the first panel (1) for connecting said panels to each other in a second direction, which is perpendicular to a main plane (MP-2) of the second panel, wherein a longitudinal direction of the separate and flexible tongue (3) extends parallel with said panel edge and/or core groove, and wherein the separate and flexible tongue (3) is arranged in an insertion groove (4), said separate and flexible tongue (3) being displaceable inwardly towards a bottom of the insertion groove (4) and outwardly into the tongue groove (5) during a locking of the first and second panel, characterized in that an engagement portion (20) of the core groove (6) is arranged to engage with said separate and flexible tongue (3) during locking of the first and second panel for displacing the separate and flexible tongue (3) inwardly towards the bottom of the insertion groove (4), wherein said engagement portion (20) is bevelled.

(53) 13. The set of panels as in embodiment 12, wherein the bevelled engagement portion (20) is provided in an upper part (30) of the first panel (1), said upper part (30) having a higher density than a center part (32) of the first panel (1).

(54) 14. The set of panels as in embodiment 12 or 13, wherein the bevelled engagement portion (20) is provided between a side wall (6a) of said core groove (6) and a lower (1a) or upper side (1b) of the first panel (1).

(55) 15. The set of panels as in any of embodiments 12 to 14, wherein the second panel (2) comprises an overlapping portion (24), which engages with the bevelled engagement portion (20) in a locked position of the first (1) and second (2) panel.

(56) 16. The set of panels as in any of embodiments 12 to 15, wherein a thickness of the second panel (2) is smaller at the panel edge (12) than in a visible part of the second panel (2) which is visible in a locked position of the first (1) and the second (2) panel.

(57) 17. The set of panels as in any of embodiments 12 to 16, wherein a distance between a lower edge side (22a) and a parallel upper edge side (22b) of the panel edge (12) is smaller than a distance between a lower side (2a) and a parallel upper side (2b), the lower and upper edge sides (22a, 22b) being located closer to a side edge (2c) of the second panel (2) than the lower and upper sides (2a, 2b).

(58) 18. The set of panels as in embodiment 17, wherein the insertion groove (4) is provided in said lower edge side (22a) or in said upper edge side (22b) of the panel edge (12).

(59) 19. A set of panels (1,2) comprising a first (1) and a second panel (2), a panel edge (12) of the second panel (2) being insertable into a core groove (6) of the first panel (1) to obtain a mechanical connection between the first and the second panel, the panel edge (12) being insertable into the core groove (6) by an essentially linear relative displacement of the first and second panel when the first and second panel are arranged essentially in the same plane (MP-1) said panel edge (12) comprising a separate and flexible tongue (3) and said core groove (6) comprising a tongue groove (5), or said panel edge (12) comprising a tongue groove (5) and said core groove (6) comprising a separate and flexible tongue (3), wherein the separate and flexible tongue (3) is insertable into the tongue groove (5) for connecting said panels to each other in a first direction, which is parallel to a main plane (MP-1) of the first panel, wherein the panel edge (12) of the second panel (2) is configured to cooperate with the core groove (6) of the first panel (1) for connecting said panels to each other in a second direction, which is perpendicular to the main plane (MP-1) of the panels (1, 2), wherein a longitudinal direction of the separate and flexible tongue (3) extends parallel with said panel edge (12) and/or core groove (6), and wherein the separate and flexible tongue (3) is arranged in an insertion groove (4), said separate and flexible tongue (3) being displaceable inwardly towards a bottom of the insertion groove (4) and outwardly into the tongue groove (5) during a locking of the first and second panel, characterized in that the separate and flexible tongue (3) comprises a guiding protrusion (10) at a short edge of the separate and flexible tongue (3), and that the guiding protrusion (10) is configured such that its shape changes during the locking and/or unlocking of the first and second panel.

(60) 20. The set of panels as in embodiment 19, wherein the guiding protrusion (10) is further configured to be in contact with an inner part of the insertion groove (4) during the locking.

(61) 21. The set of panels as in any of embodiments 19 to 20, wherein the guiding protrusion (10) is curve shaped and configured to guide a rod shaped tool (9) into the tongue groove (5) when the rod shaped tool (9) is inserted into the insertion groove (4).

(62) 22. The set of panels as in any of embodiments 19 to 21, wherein the rod shaped tool (9) comprises an essentially round cross section.