Patent Publication Number: US-2023144018-A1

Title: Panel with locking device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. application Ser. No. 17/031,166, filed on Sep. 24, 2020, which claims the benefit of Swedish Application No. 1951086-6, filed on Sep. 25, 2019. The entire contents of U.S. application Ser. No. 17/031,166 and 
     Swedish Application No. 1951086-6 are hereby incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments of the present disclosure relate to panels configured to be locked together with a mechanical locking device. The panels may be floorboards configured to be locked together to obtain a floor product. 
     TECHNICAL BACKGROUND 
     Panels are known that are configured to be assembled by a vertical displacement and to be locked together in a vertical direction and in a horizontal direction. Such panels are disclosed in e.g., WO 2018/063047. A tongue and groove connection locks a first edge of a first panel to a second edge of the second panel. The first edge and the second edge furthermore comprise a locking element configured to cooperate with a locking groove for locking in the vertical direction and the horizontal direction. 
     The above description of various known aspects is the applicant&#39;s characterization of such, and is not an admission that any of the above description is considered as prior art. 
     Embodiments of the present disclosure address a need to provide panels that can be easily assembled. 
     SUMMARY 
     It is an object of certain aspects of the present disclosure to provide an improvement over the above described techniques and known art. 
     A further object of at least certain aspects of the present disclosure is to facilitate the assembling of panels configured to be assembled by a vertical displacement or an angling motion and locked together in the vertical direction and the horizontal direction. 
     A further object of at least certain aspects of the present disclosure is to facilitate assembling of panels configured to be assembled in a way that reduces a force and impact needed from a person when assembling the panels. 
     According to a first aspect there is provided a set of panels comprising a first panel, a second panel and a mechanical locking device for locking the first panel to the second panel, the mechanical locking device being configured for an assembly by a displacement of the second panel in relation to the first panel in a vertical direction to obtain a locked position of the first panel and the second panel, wherein the first panel comprises a first edge, a first panel surface and a second panel surface, and the second panel comprises a second edge, wherein the mechanical locking device comprises a locking strip extending from the first edge in a direction parallel to the first and second panel surfaces, wherein the locking strip comprises a locking strip edge, wherein the locking strip comprises a first locking strip surface extending in a direction substantially corresponding to the direction of the first panel surface of the first panel, wherein the locking strip comprises a second locking strip surface extending in a direction substantially corresponding to the direction of the second panel surface of the first panel, wherein the locking strip comprises a locking element configured to cooperate with a locking groove at the second edge of the second panel for locking in a direction parallel to the first panel surface, wherein one of the first or second edge comprises a tongue configured to cooperate with a tongue groove at the other one of the first or second edge for locking in a vertical direction, characterized in that the mechanical locking device comprises a flexing groove extending from a transition between the first locking strip surface and the first edge and into the first panel at an angle α from the first panel surface, and that the locking strip is configured to flex by varying a shape of the flexing groove during the assembly, thereby increasing a flexibility of the locking strip during the assembly. 
     According to another aspect there is provided a set of panels comprising a first panel, a second panel and a mechanical locking device for locking the first panel to the second panel, the mechanical locking device being configured for an assembly by a displacement of the second panel in relation to the first panel in a vertical direction to obtain a locked position of the first panel and the second panel, wherein the first panel comprises a first edge, a first panel surface and a second panel surface, and the second panel comprises a second edge, wherein the mechanical locking device comprises a locking strip extending from the first edge in a direction parallel to the first and second panel surfaces, wherein the locking strip comprises a locking strip edge, wherein the locking strip comprises a first locking strip surface extending in a direction substantially corresponding to the direction of the first panel surface of the first panel, wherein the locking strip comprises a second locking strip surface extending in a direction substantially corresponding to the direction of the second panel surface of the first panel, wherein the locking strip comprises a locking element configured to cooperate with a locking groove at the second edge of the second panel for locking in a direction parallel to the first panel surface, wherein one of the first or second edge comprises a tongue configured to cooperate with a tongue groove at the other one of the first or second edge for locking in a vertical direction, characterized in that the mechanical locking device comprises a flexing groove extending from a transition between the first locking strip surface and the first edge and into the first panel at an angle α from the first panel surface, wherein the angle α is within the range of about 0° to about 30°, preferably within the range of about 0° to about 20°, more preferably within the range of about 0° to about 10°, even more preferably within the range of about 0° to about 5°, and that the locking strip is configured to flex by varying a shape of the flexing groove during the assembly, thus increasing a flexibility of the locking strip during the assembly. 
     According to an aspect an opening of the flexing groove has a width T. 
     According to an aspect the width T of the opening of the flexing groove is within the range of about 0.6 mm to about 2.5 mm, preferably about 0.8 mm to about 2.0 mm, more preferably 1.6 mm. 
     According to an aspect a ratio between the width T of the opening of the flexing groove and a distance Q between the first panel surface and the second panel surface is within the range of about 0.05 to about 0.4, preferably about 0.1 to about 0.3, more preferably about 0.15 to about 0.2. 
     According to an aspect the flexing groove has a depth D that is within the range of about 2.5 mm to about 15 mm, preferably about 4 mm to about 12 mm, more preferably about 5 mm to about 10 mm, even more preferably about 7 mm. 
     According to an aspect a ratio between the depth D of the flexing groove and the width T of the flexing groove is about 2 to about 10, preferably about 3 to about 7, more preferably about 4. 
     According to an aspect the flexing groove has a bottom. 
     According to an aspect a ratio between a length M of the bottom of the flexing groove and the width T of the opening of the flexing groove is within the range of about 0.5 to about 2, preferably about 0.8 to about 1.4, more preferably about 1 to about 1.25. 
     According to an aspect the first locking strip edge is positioned at a distance Z from the first edge, wherein Z is within the range of about 4 mm to about 12 mm, preferably about 6 mm to about 9 mm, more preferably about 7.5 mm to about 8.5 mm. 
     According to an aspect a ratio between the distance Z and the width T of the opening of the flexing groove is within the range of about 2 to about 10, preferably about 4 to about 6, more preferably about 5. 
     According to an aspect the flexing groove has a length L. 
     According to an aspect the first panel comprises a third edge and a fourth edge, the third edge being at a distance TL from the fourth edge. 
     According to an aspect the length L of the flexing groove extends from the third edge of the first panel to the fourth edge of the first panel. 
     According to an aspect the flexing groove has a fifth edge and a sixth edge, the fifth edge being positioned at a distance X from the third edge and the sixth edge being positioned at a distance X from the fourth edge. 
     According to an aspect the distance X is within the range of about 1 mm to about 30 mm, preferably about 5 mm to about 20 mm, more preferably about 10 mm. 
     According to an aspect the bottom of the flexing groove is essentially arch shaped. 
     According to an aspect the bottom of the flexing groove is essentially triangular. 
     According to an aspect a cross-sectional shape of the flexing groove is essentially rectangular or square. 
     According to an aspect the opening of the flexing groove that is connected to the first edge is positioned at a distance A1 in a vertical direction from the first panel surface. 
     According to an aspect the distance A1 is within the range of about 2 mm to about 7 mm, preferably about 3 mm to about 6 mm, more preferably about 4 mm to about 5 mm. 
     According to an aspect the bottom of the flexing groove is positioned at a distance A3 in a vertical direction from the second panel surface. 
     According to an aspect the distance A3 is within the range of about 1 mm to about 7 mm, preferably about 1.25 mm to about 3 mm, more preferably about 1.5 mm to about 2 mm. 
     According to an aspect the flexing groove extends a distance A2 in a direction essentially perpendicular to the second panel surface, wherein A2 is equal to the distance Q minus distance A1 minus distance A3 ((Q)−(A1)−(A3)). 
     According to an aspect a ratio between the distance A2 and the distance A3 is about 0.8 to about 3, preferably about 1 to about 2, more preferably about 1.25 to about 1.75. 
     According to an aspect a ratio between the distance A2 and the distance A1 is about 0.3 to about 1.2, preferably about 0.4 to about 0.9, more preferably about 0.5. 
     According to an aspect a ratio between the sum of distance A2 plus distance A3 and the distance Q (((A2)+(A3))/(Q)) is about 0.2 to about 0.5, preferably about 0.25 to about 0.40, more preferably about 0.30 to about 0.35. 
     According to an aspect the mechanical locking device is configured to lock the first panel and the second panel in a first direction parallel to the first panel surface and/or in a second direction perpendicular to the first panel surface. 
     According to an aspect the core of the first panel and/or of the second panel may be a wood-based core, preferably made of MDF, HDF, OSB, WPC, plywood or particleboard. The core may also be a plastic core comprising thermosetting plastic or thermoplastic e.g., vinyl, PVC, PU or PET. The plastic core may comprise fillers. The core may also be mineral based board which may comprise e.g., MgO. 
     The first panel and/or the second panel may also be of solid wood. 
     The first panel and/or the second panel may be provided with a decorative layer, such as a foil or a veneer, on one or more surfaces. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects, features and advantages of which embodiments of the disclosure are capable of, will be apparent and elucidated from the following description of embodiments and aspects of the present disclosure, reference being made to the accompanying drawings. 
         FIG.  1 A  shows a side view of an illustrative set in an unassembled state, where the bottom of the flexing groove is essentially arch shaped. 
         FIG.  1 B  shows a side view of an illustrative set in an assembled state, where the bottom of the flexing groove is essentially arch shaped. 
         FIG.  2 A  shows a side view of an illustrative set in an unassembled state, where the bottom of the flexing groove is essentially triangular. 
         FIG.  2 B  shows a side view of an illustrative set in an assembled state, where the bottom of the flexing groove is essentially triangular. 
         FIG.  3    shows a side view of an illustrative set in an unassembled state. 
         FIG.  4 A  shows a view of an illustrative first panel comprising a flexing groove which extends over the whole length of the first panel. 
         FIG.  4 B  shows a side view of an illustrative first panel comprising a flexing groove which does not extend the whole length of the first panel, but which extends a distance X from the third edge of the first panel to a distance X from the fourth edge of the first panel. 
         FIG.  4 C  shows an illustrative embodiment of a first panel comprising flexing groove which is not continuous, but which is divided into two or more flexing grooves running in line with a space between them. 
     
    
    
     DETAILED DESCRIPTION 
     Specific embodiments of the disclosure will now be described with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. The terminology used in the detailed description of the embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, like numbers refer to like elements. 
     The terminology used herein is for the purpose of describing particular aspects of the disclosure only, and is not intended to limit the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     It should be noted that the word “comprising” does not necessarily exclude the presence of other elements or steps than those listed and the words “a” or “an” preceding an element do not exclude the presence of a plurality of such elements. It should further be noted that any reference signs do not limit the scope of the claims, that the example aspects may be implemented at least in part by means of both hardware and software, and that several “means”, “units” or “devices” may be represented by the same item of hardware. 
     The different aspects, alternatives and embodiments of the disclosure herein can be combined with one or more of the other aspects, alternatives and embodiments described herein. Two or more aspects can be combined. 
     A first aspect of the disclosure is shown, e.g., in  FIGS.  1 A- 3   , which show illustrative sets of panels comprising a first panel  1 , a second panel  2  and a mechanical locking device for locking the first panel  1  to the second panel  2 . The mechanical locking device is configured for an assembly by a displacement of the second panel  2  in relation to the first panel  1  in a vertical direction to obtain a locked position of the first panel  1  and the second panel  2 . The first panel  1  comprises a first edge  11 , a first panel surface  12  and a second panel surface  13 . The second panel  2  comprises a second edge  21 . The mechanical locking device comprises a locking strip  7  extending from the first edge  11  in a direction parallel to the first and second panel surfaces  12 , 13 , wherein the locking strip  7  comprises a locking strip edge  71 , wherein the locking strip  7  comprises a first locking strip surface  72  extending in a direction substantially corresponding to the direction of the first panel surface  12  of the first panel  1 , wherein the locking strip  7  comprises a second locking strip surface  73  extending in a direction substantially corresponding to direction of the second panel surface  13  of the first panel  1 , and wherein the locking strip  7  comprises a locking element  3  configured to cooperate with a locking groove  4  at the second edge  21  of the second panel  2  for locking in a direction parallel to the first panel surface  12 . By “substantially corresponding” it is meant that the noted directions may form an angle within a range of +/−10 degrees. One of the first or second edge  11 ,  21  comprises a tongue  5  configured to cooperate with a tongue groove  6  at the other one of the first or second edge  11 ,  21  for locking in a vertical direction. The set is characterized in that the mechanical locking device comprises a flexing groove  8  extending from a transition between the first locking strip surface  72  and the first edge  11  and into the first panel  1  at an angle α from the first panel surface  12 , and that the locking strip  7  is configured to flex by varying a shape of the flexing groove  8  during the assembly, thereby increasing a flexibility of the locking strip  7  during the assembly. 
     In one aspect the angle α is within the range of about 0° to about 30°, preferably within the range of about 0° to about 20°, more preferably within the range of about 0° to about 10°, even more preferably within the range of about 0° to about 5°, and the flexing groove  8  is configured to increase a flexibility of the locking strip  7  during the assembly. A smaller angle α may be preferred for panels with a smaller thickness Q to allow for a first flexing groove  8  with a greater depth D. 
     The increased flexibility of the locking strip  7  during assembly results in an increased distance between the first edge  11  and the locking element  3 . This results in an easier assembly of the first  1  and second  2  panels. 
     The first panel  1  and the second panel  2  are preferably floorboards to be locked together to obtain a floor product. 
     An opening of the flexing groove  8  may have a width T. The width T of the opening of the flexing groove  8  may be within the range of about 0.6 mm to about 2.5 mm, preferably about 0.8 mm to about 2.0 mm, more preferably about 1.6 mm. The values are high enough to allow an easy assembling and low enough to allow a sufficient locking strength. A width T of 2 mm may provide an easier assembling and width T of 0.6 mm may provide a higher locking strength. The preferred value can depend on e.g. the material of the locking strip. A greater width may have the advantage that the risk for cracks are reduced, particularly for brittle materials, such as HDF and plastic material with a high amount of fillers. 
     A ratio between the width T of the opening of the flexing groove  8  and a distance Q between the first panel surface  12  and the second panel surface  13  may be within the range of about 0.05 to about 0.4, preferably about 0.1 to about 0.3, more preferably about 0.15 to about 0.2. The ratios are high enough to allow an easy assembling and low enough to allow a sufficient locking strength. A ratio of 0.4 may provide an easier assembling and a ratio of 0.05 may provide a higher locking strength. The preferred value can depend on e.g. the material of the locking strip. A greater ratio may have the advantage that the risk for cracks are reduced, particularly for brittle materials, such as HDF and plastic material with a high amount of fillers. 
     The flexing groove  8  may have a depth D that may be within the range of about 2.5 mm to about 15 mm, preferably about 4 mm to about 12 mm, more preferably about 5 mm to about 10 mm, even more preferably about 7 mm. The values are high enough to allow an easy assembling and low enough to allow a sufficient locking strength. A depth D of 15 mm may provide an easier assembling and depth D of 2.5 mm may provide a higher locking strength. The preferred value can depend on e.g. the material of the locking strip. 
     A ratio between the depth D of the flexing groove  8  and the width T of the flexing groove  8  may be about 2 to about 10, preferably about 3 to about 7, more preferably about 4. The ratios are high enough to allow an easy assembling and low enough to allow a sufficient locking strength. A ratio of 10 may provide an easier assembling and a ratio of 2 may provide a higher locking strength. The preferred value can depend on e.g. the material of the locking strip. 
     The flexing groove  8  may have a bottom  81 . A ratio between a length M of the bottom  81  of the flexing groove  8  and the width T of the opening of the flexing groove  8  may be within the range of about 0.5 to about 2, preferably about 0.8 to about 1.4, more preferably about 1 to about 1.25. The ratios are high enough to allow an easy assembling and low enough to allow a sufficient locking strength. A ratio of 1.4, as shown in  FIG.  2 B , may provide an easier assembling and a ratio of 1, as shown in  FIG.  1 B , may provide a higher locking strength. The preferred value can depend on e.g. the material of the locking strip. 
     The first locking strip edge  71  may be positioned at a distance Z from the first edge  11 , wherein Z is within the range of about 4 mm to about 12 mm, preferably about 6 mm to about 9 mm, more preferably about 7.5 mm to about 8.5 mm. A greater distance Z may allow a greater flexibility and an easier assembling. 
     A ratio between the distance Z and the width T of the opening of the groove flexing  8  may be within the range of about 2 to about 10, preferably about 4 to about 6, more preferably about 5. A greater distance Z may allow the same flexibility for a smaller width T. 
     Illustrative aspects of the first panel  1  are shown in  FIGS.  4 A- 4 C . 
     The flexing groove  8  may have a length L. 
     The first panel  1  may comprise a third edge  14  and a fourth edge  15 , the third edge  14  being at a distance TL from the fourth edge  15 . 
     The length L of the flexing groove  8  may extend from the third edge  14  of the first panel  1  to the fourth edge  15  of the first panel  1 , such that L=TL, as shown in  FIG.  4 A . 
     As shown for example in  FIG.  4 B , the flexing groove  8  may have a fifth  82  edge and a sixth  83  edge, where the fifth edge  82  may be positioned at a distance X from the third  14  edge and the sixth edge  83  may be positioned at a distance X from the fourth edge  15 . The distance X may be within the range of about 1 mm to about 30 mm, preferably about 5 mm to about 20 mm, more preferably about 10 mm. According to this aspect, the flexing groove  8  does not extend over the whole distance TL from the third edge  14  to the fourth edge  15  of the first panel  1 . 
     As shown for example in  FIG.  4 C , in one aspect the flexing groove is not continuous over the first panel  1 , but may be divided into two or more flexing grooves  8  with a space between them. These flexing grooves  8  can be spaced apart and collinear. In one aspect the space between said two or more flexing grooves  8  may be within the range of about 1 mm to about 30 mm. 
     In one aspect the bottom  81  of the flexing groove  8  may be essentially arch shaped. 
     In one aspect the bottom  81  of the flexing groove  8  may be essentially triangular. 
     In one aspect a cross-sectional shape of the flexing groove  8  may be essentially rectangular or square. 
     As shown for example in  FIG.  3   , the opening of the flexing groove  8  that is connected to the first edge  11  may be positioned at a distance A1 in a vertical direction from the first panel surface  12 . 
     The distance A1 may be within the range of about 2 mm to about 7 mm, preferably about 3 mm to about 6 mm, more preferably about 4 mm to about 5 mm. 
     The bottom  81  of the flexing groove  8  may be positioned at a distance A3 in a vertical direction from the second panel surface  13 . The distance A3 may be within the range of about 1 mm to about 7 mm, preferably about 1.25 mm to about 3 mm, more preferably about 1.5 mm to about 2 mm. 
     The flexing groove  8  may extend a distance A2 in a direction essentially perpendicular to the second panel surface  13 , wherein A2 is equal to the distance Q minus the distance A1 minus the distance A3 ((Q)−(A1)−(A3)). 
     A ratio between the distance A2 and the distance A3 may be about 0.8 to about 3, preferably about 1 to about 2, more preferably about 1.25 to about 1.75. The ratios are high enough to allow an easy assembling and low enough to allow a sufficient locking strength. A ratio of 3 may provide an easier assembling and a ratio of 0.8 may provide a higher locking strength. The preferred value can depend on e.g. the material of the locking strip. 
     A ratio between the distance A2 and the distance A1 may be about 0.3 to about 1.2, preferably about 0.4 to about 0.9, more preferably about 0.5. The ratios are high enough to allow an easy assembling and low enough to reduce the risk of warping of the first and/or the second edge  11 ,  21  due to e.g. humidity changes and/or to allow for a sufficient locking strength in the vertical direction. A ratio of 3 may provide an easier assembling and a ratio of 0.8 may provide a higher locking strength in the vertical direction. The preferred value can depend on e.g. the material of the locking strip. 
     A ratio between the sum of the distance A2 plus the distance A3 and the distance Q (((A2)+(A3))/(Q)) may be about 0.2 to about 0.5, preferably about 0.25 to about 0.40, more preferably about 0.30 to about 0.35. The ratios are low enough to allow an easy assembling and high enough to reduce the risk of warping of the first and/or the second edge  11 ,  21  due to e.g. humidity changes and/or to allow for a sufficient locking strength in the vertical direction. A ratio of 0.2 may provide an easier assembling and a ratio of 0.5 may provide a higher locking strength in the vertical direction. The preferred value can depend on e.g. the material of the locking strip. 
     The mechanical locking device is configured to lock the first panel  1  and the second panel  2  in a first direction parallel to the first panel surface  12  and/or in a second direction perpendicular to the first panel surface  12 . 
     The core of the first panel  1  and/or of the second panel  2  may be a wood-based core, preferably made of MDF, HDF, OSB, WPC, plywood or particleboard. The core may also be a plastic core comprising thermosetting plastic or thermoplastic e.g., vinyl, PVC, PU or PET. The plastic core may comprise fillers. The core may also be a mineral based board which may comprise e.g., MgO. 
     The first panel  1  and/or the second panel  2  may also be of solid wood. 
     The first panel  1  and/or the second panel  2  may be provided with a decorative layer, such as a foil or a veneer, on one or more surfaces. 
     The first panel  1  and the second panel  2  may be of a rectangular shape. 
     The first panel  1  may comprise an edge opposite the first edge which is essentially identical to the second edge of the second panel  2 . 
     The second panel  2  may comprise an edge opposite the second edge which is essentially identical to the first edge of the first panel  1 . 
     The first edge and the second edge may be short edges of the first panel and the second panel. 
     The assembling may also comprise an angling motion along a long side of the first panel and/or the second panel. 
     Further embodiments of the disclosure are described below: 
     1. A set of panels comprising a first panel ( 1 ), a second panel ( 2 ) and a mechanical locking device for locking the first panel ( 1 ) to the second panel ( 2 ), the mechanical locking device being configured for an assembly by a displacement of the second panel ( 2 ) in relation to the first panel ( 1 ) in a vertical direction to obtain a locked position of the first panel ( 1 ) and the second panel ( 2 ), wherein the first panel ( 1 ) comprises a first edge ( 11 ), a first panel surface ( 12 ) and a second panel surface ( 13 ) and the second panel ( 2 ) comprises a second edge ( 21 ),
         wherein the mechanical locking device comprises a locking strip ( 7 ) extending from the first edge ( 11 ) in a direction parallel to the first and second panel surfaces ( 12 ,  13 ),   wherein the locking strip ( 7 ) comprises a locking strip edge ( 71 ),   wherein the locking strip ( 7 ) comprises a first locking strip surface ( 72 ) extending in a direction substantially corresponding to the direction of the first panel surface ( 12 ) of the first panel ( 1 ),   wherein the locking strip ( 7 ) comprises a second locking strip surface ( 73 ) extending in a direction substantially corresponding to the direction of the second panel surface ( 12 ) of the first panel ( 1 ),   wherein the locking strip ( 7 ) comprises a locking element ( 3 ) configured to cooperate with a locking groove ( 4 ) at the second edge ( 21 ) of the second panel ( 2 ) for locking in a direction parallel to the first panel surface ( 12 ),   wherein one of the first or second edge ( 11 ,  21 ) comprises a tongue ( 5 ) configured to cooperate with a tongue groove ( 6 ) at the other one of the first or second edge ( 11 ,  21 ) for locking in a vertical direction,   wherein the mechanical locking device comprises a flexing groove ( 8 ) extending from a transition between the first locking strip surface ( 72 ) and the first edge ( 11 ) and into the first panel ( 1 ) at an angle (a) from the first panel surface ( 12 ), wherein the angle (a) is within the range of about 0° to about 30°, preferably within the range of about 0° to about 20°, more preferably within the range of about 0° to about 10°, even more preferably within the range of about 0° to about 5°, and wherein the locking strip ( 7 ) is configured to flex by varying a shape of the flexing groove ( 8 ) during the assembly, thereby increasing a flexibility of the locking strip ( 7 ) during the assembly.       

     2. The set of panels as described in embodiment 1, wherein an opening of the flexing groove ( 8 ) has a width T. 
     3. The set of panels as described in embodiment 2, wherein the width T of the opening of the flexing groove ( 8 ) is within the range of about 0.6 mm to about 2.5 mm, preferably about 0.8 mm to about 2.0 mm, more preferably about 1.6 mm. 
     4. The set of panels as described in any one of the previous embodiments 1-3, wherein a ratio between a width T of the opening of the flexing groove ( 8 ) and a distance Q between the first panel surface ( 12 ) and the second panel surface ( 13 ) is within the range of about 0.05 to about 0.4, preferably about 0.1 to about 0.3, more preferably about 0.15 to about 0.2. 
     5. The set of panels as described in any one of the previous embodiments 1-4, wherein the flexing groove ( 8 ) has a depth D that is within the range of about 2.5 mm to about 15 mm, preferably about 4 mm to about 12 mm, more preferably about 5 mm to about 10 mm, even more preferably about 7 mm. 
     6. The set of panels as described in embodiment 5, wherein a ratio between the depth D of the flexing groove ( 8 ) and the width T of the flexing groove ( 8 ) is about 2 to about 10, preferably about 3 to about 7, more preferably about 4. 
     7. The set of panels as described in any one of the previous embodiments 1-6, wherein the flexing groove ( 8 ) has a bottom ( 81 ). 
     8. The set of panels as described in embodiment 7, wherein a ratio between a length M of the bottom ( 81 ) of the flexing groove ( 8 ) and the width T of the opening of the flexing groove ( 8 ) is within the range of about 0.5 to about 2, preferably about 0.8 to about 1.4, more preferably about 1 to about 1.25. 
     9. The set of panels as described in any one of the previous embodiments 1-8, wherein the first locking strip edge ( 71 ) is positioned at a distance Z from the first edge ( 11 ), wherein Z is within the range of about 4 mm to about 12 mm, preferably about 6 mm to about 9 mm, more preferably about 7.5 mm to about 8.5 mm. 
     10. The set of panels as described in embodiment 9, wherein the ratio between the distance Z and the width T of the opening of the groove flexing ( 8 ) is within the range of about 2 to about 10, preferably about 4 to about 6, more preferably about 5. 
     11. The set of panels as described in any one of the previous embodiments 1-10, wherein the flexing groove ( 8 ) has a length L. 
     12. The set of panels as described in any one of the previous embodiments 1-11, wherein the first panel ( 1 ) comprises a third edge ( 14 ) and a fourth edge ( 15 ), the third edge ( 14 ) being at a distance TL from the fourth edge ( 15 ). 
     13. The set of panels as described in embodiment 12, wherein the length L of the flexing groove ( 8 ) extends from the third edge ( 14 ) of the first panel ( 1 ) to the fourth edge ( 15 ) of the first panel ( 1 ). 
     14. The set of panels as described in any one of the previous embodiments 1 to 13, wherein the flexing groove ( 8 ) has a fifth ( 82 ) edge and a sixth ( 83 ) edge, the fifth edge ( 82 ) being positioned at a distance X from the third ( 14 ) edge and the sixth edge ( 83 ) being positioned at a distance X from the fourth edge ( 15 ). 
     15. The set of panels as described in embodiment 14, wherein the distance X is within the range of about 1 mm to about 30 mm, preferably about 5 mm to about 20 mm, more preferably about 10 mm. 
     16. The set of panels as described in any one of the previous embodiments 1-15, wherein the bottom ( 81 ) of the flexing groove ( 8 ) is essentially arch shaped. 
     17. The set of panels as described in any one of the previous embodiments 1 to 15, wherein the bottom ( 81 ) of the flexing groove ( 8 ) is essentially triangular. 
     18. The set of panels as described in any one of the previous embodiments 1 to 15, wherein a cross-sectional shape of the flexing groove ( 8 ) is essentially rectangular or square. 
     19. The set of panels as described in any one of the previous embodiments 1-18, wherein the opening of the flexing groove ( 8 ) that is connected to the first edge ( 11 ) is positioned at a distance A1 in a vertical direction from the first panel surface ( 12 ). 
     20. The set of panels as described in embodiment 19, wherein the distance A1 is within the range of about 2 mm to about 7 mm, preferably about 3 mm to about 6 mm, more preferably about 4 mm to about 5 mm. 
     21. The set of panels as described in any one of the previous embodiments 1-21, wherein the bottom ( 81 ) of the flexing groove ( 8 ) is positioned at a distance A3 in a vertical direction from the second panel surface ( 13 ). 
     22. The set of panels as described in embodiment 21, wherein the distance A3 is within the range of about 1 mm to about 7 mm, preferably about 1.25 mm to about 3 mm, more preferably about 1.5 mm to about 2 mm. 
     23. The set of panels as described in embodiment 22, wherein the flexing groove ( 8 ) extends a distance A2 in a direction essentially perpendicular to the second panel surface ( 13 ), wherein A2 is equal to the distance Q minus the distance A1 minus the distance A3 ((Q)−(A1)−(A3)). 
     24. The set of panels as described in embodiment 23, wherein a ratio between the distance A2 and the distance A3 is about 0.8 to about 3, preferably about 1 to about 2, more preferably about 1.25 to about 1.75. 
     25. The set of panels as described in embodiment 23 or embodiment 24, wherein a ratio between the distance A2 and the distance A1 is about 0.3 to about 1.2, preferably about 0.4 to about 0.9, more preferably about 0.5. 
     26. The set of panels as described in any one of embodiments 23 to 25, wherein a ratio between the sum of the distance A2 plus the distance A3 and the distance Q (((A2)+(A3))/(Q)) is about 0.25 to about 0.5, preferably about 0.25 to about 0.40, more preferably about 0.30 to about 0.35. 
     27. The set of panels as described in any one of the previous embodiments 1-26, wherein the mechanical locking device is configured to lock the first panel  1  and the second panel  2  in a first direction parallel to the first panel surface  12  and/or in a second direction perpendicular to the first panel surface  12 .