Patent Publication Number: US-2022228372-A1

Title: Set of panels

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 17/029,658, filed on Sep. 23, 2020, which claims the benefit of European Application No. 19199250.2, filed on Sep. 24, 2019. The entire contents of U.S. patent application Ser. No. 17/029,658 and European Application No. 19199250.2 are hereby incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments of the present disclosure relates to panels, such as floorboards, which are configured to be locked together by a vertical displacement. 
     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., WO2018/063047 and WO2014/209213. A tongue and groove connection locks a first edge of a first panel to a second edge of the second panel in a second direction. 
     The first edge and the second edge furthermore comprise a locking element configured to cooperate with a locking groove for locking in a first direction, which is perpendicular to the second direction. 
     Embodiments of the present disclosure address a need to provide an easier assembling and/or an increased locking strength of the panels. 
     SUMMARY 
     It is an object of at least certain embodiments of the present disclosure to provide an improvement over the above described techniques and known art. 
     A further object of at least certain embodiments of the present disclosure is to facilitate assembling of panels configured to be assembled by a vertical displacement and locked together in the vertical direction and the horizontal direction. 
     Another object of at least certain embodiment of the present disclosure is to increase the locking strength by preventing or at least decreasing damage of edges of the panels, particularly parts of the edges that have a locking function. The locking strength may also be increased by an improved configuration of locking surfaces at the edges of the panels. 
     At least some of these and other objects and advantages that may be apparent from the description have been achieved by a first aspect of the disclosure including a set of panels comprising a first panel and a second panel, wherein the first panel comprising a first edge, a first panel surface and a second opposite panel surface and the second panel comprises a second edge, a third panel surface and an opposite fourth panel surface. The first edge comprises a locking strip with a locking element configured to cooperate with a locking groove at the second edge of the second panel for locking the first edge to the second edge in a first direction which is parallel to the first panel surface. The first edge is configured to be assembled to the second edge by a displacement of the second edge relative the first edge in an assembly direction, which is perpendicular to the first panel surface, to obtain a locked position of the first edge and the second edge. The locking element comprises a first locking surface at a first angle from a plane parallel to the first panel surface and the locking groove comprises a second locking surface at a second angle from a plane parallel to the third panel surface. The first angle is different from the second angle such that the first locking surface converges towards the second locking surface at a cooperation part in the locked position. The first locking surface cooperates with the second locking surface at the cooperation part for the locking in the first direction. 
     The converging locking surfaces may have the effect that a load in the first direction, e.g. from a force pulling apart the panels, is absorbed at a part with a shorter moment arm. A shorter moment arm may have the advantage that the locking strength is increased. 
     The converging locking surfaces may have the effect that the area of contact between the first and the second locking surface is decreased during assembling. The decreased area of contact during assembling may have the advantage that the friction during assembling is decreased and the assembling is facilitated. 
     The locking element may comprise a first guiding surface at an outer surface and the locking groove may comprise a second guiding surface at an opening of the locking groove. The first guiding surface is configured to cooperate with the second guiding surface during assembling to guide the locking element into the locking groove. 
     The size of the first guiding surface may be greater than the size of the second guiding surface which may have the effect that the guiding is improved. 
     The first guiding surface may comprise an essentially planar surface. 
     The second guiding surface may have a rounded shape. 
     A ratio between a length of the planar surface and a radius of the rounded shape may be in the range of about 1 to about 5, or about 2 to about 4, or about 3. 
     The cooperation part may be closer to a strip surface of the locking strip than to an outer surface of the locking element. 
     There may be a space between the first locking surface and the second locking surface in the locked position, wherein the space is located between the cooperation part and an outer surface of the locking element. 
     An outer part of the locking element may be damaged during the assembling if the panel material is brittle or comprises imperfections. The space may have the advantage that it allows a desired locked position to be reached even in an event that an outer part of the locking element is damaged. 
     The difference between the first angle and the second angle may be in the range of about 5° to about 15°, or in the range of about 5° to about 10°, or about 7°. 
     The cooperation part may be positioned at a first distance from a strip surface of the locking strip, wherein an outer surface of the locking element is positioned at a second distance from a strip surface of the locking strip, and wherein a ratio between the first distance and the second distance is in the range of about 0.03 to about 0.3, or in the range of about 0.1 to about 0.2, 03, or about 0.15. 
     The first edge or the second edge may comprise a tongue which is configured to cooperate with a tongue groove at the other of the first edge or the second edge for a locking in a second direction which is perpendicular to the first direction. 
     The tongue may be a flexible tongue which is located in an insertion groove at the first edge or the second edge. 
     The first angle may be in the range of about 90° to about °  145 , or in the range of about 100° to about 135°, or in the range of about 110° to about 125°, or about 120° and wherein the second angle may be in the range of about 80° to about 135°, or in the range of about 100° to about 115°, or about 110°. 
     The locking surface and second locking surface may be configured for a locking in a second direction which is perpendicular to the first direction. 
     The first angle may be in the range of about 70° to about 90°, or in the range of about 80° to about 89°, or in the range of about 85° to about 89°, and the second angle may be in the range of about 75° to about 85°, or in the range of about 80° to about 85°. 
     The panels may comprise a polymer material or a wood based material. 
     The distance between the first panel surface and the second panel surface may be in the range of about 3 mm to about 15 mm, or in the range of about 5 mm to about 8 mm. 
     A distance between the third panel surface and the fourth panel surface may be in the range of about 3 mm to about 15 mm, or in the range of about 5 mm to about 8 mm. 
     The first panel surface and the third panel surface may comprise a decorative surface. 
     The assembling may comprise a displacement in the horizontal direction. 
     The first and the second panel may be of a rectangular shape. 
     The first and the second panel may be building panels, such as floor panels, wall panels or ceiling panels. 
     The first edge and the second edge may be short edges of the first and the second panel. 
     The assembling may also comprise an angling motion along a long side of the first and/or the second panel. The angling motion may at the same time connect the long side of the first and/or the second panel to a side of a third panel by a mechanical locking device. 
     The first panel and the second panel may be resilient panels. The resilient panels may comprise a core comprising thermoplastic material. The thermoplastic material may be foamed. 
     The thermoplastic material may comprise polyvinyl chloride (PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate, methacrylate, polycarbonate, polyvinyl butyral, polybutylene terephthalate, or a combination thereof. The core may be formed of several layers. 
     The first panel and the second panel may comprise a decorative layer, such as a decorative foil comprising a thermoplastic material. The thermoplastic material of the decorative layer may be or comprise polyvinyl chloride (PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate, methacrylate, polycarbonate, polyvinyl butyral, polybutylene terephthalate, or a combination thereof. The decorative foil is preferably printed, for example by direct printing, rotogravure, or digital printing. 
     The first panel and the second panel may comprise a wear layer such as a film or foil. The wear layer may comprise thermoplastic material. The thermoplastic material may be polyvinyl chloride (PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate, methacrylate, polycarbonate, polyvinyl butyral, polybutylene terephthalate, or a combination thereof. 
     Embodiments of the disclosure may be particularly advantageous for panels comprising locking surfaces with higher friction. 
     The first and the second panel may comprise a wood-based core, such as HDF, MDF or plywood. 
    
    
     
       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 of the present disclosure, reference being made to the accompanying drawings, in which 
         FIGS. 1A-1C  show illustrative embodiments of the set of panels in a locked position. 
         FIG. 2A  shows the illustrative embodiment in  FIG. 1A  during assembling. 
         FIG. 2B  shows the illustrative embodiment in  FIG. 1B  during assembling. 
         FIGS. 3A-3B  show the illustrative embodiment of  FIG. 1B  before assembling. 
         FIGS. 4A-4B  show the illustrative embodiment of  FIG. 1A  before assembling 
         FIG. 5  shows an enlargement of the locking element, the locking strip and the locking groove of the illustrative embodiments of  FIGS. 1B, 1C and 7 . 
         FIG. 6  shows an enlargement of the locking element, the locking strip and the locking groove of the illustrative embodiment of  FIG. 1A . 
         FIG. 7  shows an illustrative embodiment of the set of panels in a locked position. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     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. 
     Embodiments of the set of panels are according to the disclosure are shown in a locked position in  FIGS. 1A-1C and 7 . The set of panels comprises a first panel  1  and a second panel  2 , wherein the first panel  1  comprises a first edge  17 , a first panel surface  15  and a second opposite panel surface  16 , and wherein the second panel  2  comprises a second edge  18 , a third panel surface  13  and an opposite fourth panel surface  14 . The first edge  17  comprises a locking strip  19  with a locking element  5  configured to cooperate with a locking groove  4  at the second edge  18  of the second panel  2  for locking the first edge  17  to the second edge  18  in a first direction  12  which is parallel to the first panel surface  15 . The first edge  17  is configured to be assembled to the second edge  18  by a displacement of the second edge  18  relative the first edge  17  in an assembly direction  10 , which is perpendicular to the first panel surface  15 , to obtain a locked position of the first edge  17  and the second edge  18   
     As shown for example in  FIGS. 3A and 3B , the locking element  5  comprises a first locking surface  31  at a first angle  101  from a plane parallel to the first panel surface  15  and the locking groove  4  comprises a second locking surface  32  at a second angle  102  from a plane parallel to the third panel surface  13 . The first angle  101  is different from the second angle  102  such that the first locking surface  31  converges towards the second locking surface  32  at a cooperation part  104  (see, e.g.,  FIGS. 5 and 6 ) in the locked position, and that the first locking surface  31  cooperates with the second locking surface  32  at the cooperation part  104  for the locking in the first direction  12 . In illustrative embodiments, the cooperation part  104  is a point of intersection of the first locking surface  31  and the second locking surface  32 . The converging locking surfaces may have the effect that a load in the first direction  12 , e.g. from a force pulling apart the panels, is absorbed at a part with a shorter moment arm. A shorter moment arm may have the advantage that the locking strength is increased. 
     The converging locking surfaces may have the effect that the area of contact between the first and the second locking surface is decreased during assembling. The decreased area of contact during assembling may have the advantage that the friction during assembling is decreased and the assembling is facilitated. 
       FIG. 5  shows an enlargement of the locking element  5 , the locking strip  19  and the locking groove  4  of the embodiments of  FIGS. 1B, 1C and 7 . 
       FIG. 6  shows an enlargement of the locking element  5 , the locking strip  19  and the locking groove  4  of the embodiment of  FIG. 1A . 
       FIGS. 5 and 6  show embodiments comprising a cooperation part  104  which is closer to a strip surface  36  of the locking strip  19  than to an outer surface  7  of the locking element  5 . 
     The outer surface  7  may be an outermost surface of the locking element  5 . For example, in  FIG. 5 , the outer surface  7  may be an uppermost surface of the locking element  5 . 
     The illustrative embodiments of  FIGS. 5 and 6  comprise a space  115  between the first locking surface  31  and the second locking surface  32 . The space is located between the cooperation part  104  and an outer surface  7  of the locking element  5 . 
     The difference  103  between the first angle  101  and the second angle  102  may be in the range of about 2° to about 15°, or in the range of about 5° to about 10°, or in the range of about 5° to about 7°, or about 7. If the difference is smaller than 2° the space  115  may be too small to accommodate dust or particles from parts of the panels that are damaged during assembling or transportation. A greater difference, e.g. greater than 5°, may be an advantage since it allows lower production tolerances. A difference greater than 15° may be a disadvantage since it may result in a weak edge at the opening of the locking groove  4  at the second guiding surface  22 . 
     It shall be understood that the term “about” includes a margin for a measurement error of 1°. 
     The cooperation part  104  is positioned at a first distance  113  from a strip surface  36  of the locking strip  19 , wherein an outer surface  7  of the locking element  5  is positioned at a second distance  114  from a strip surface  36  of the locking strip  19 , and wherein a ratio between the first distance  114  and the second distance  114  may be in the range of about 0.03 to about 0.3, or in the range of about 0.1 to about 0.2, about 0.3, or about 0.15. A short first distance has the advantage of a shorter moment arm. The second distance may be long enough to allow for the first guiding  20  surface and to reduce the risk that the locking element slides out from the locking groove when a high load is applied to the panels which may cause the locking strip to bend away from the locking groove. 
       FIGS. 1A-1C  show that the first edge  17  or the second edge  18  may comprise a tongue  3  which is configured to cooperate with a tongue groove  6  at the other of the first edge  17  or the second edge  18  for a locking in a second direction  11  which is perpendicular to the first direction  12 .  FIG. 1A  shows an embodiment comprising an embodiment of the tongue  3 , which is a flexible tongue located in an insertion groove. The insertion groove may be located at the first edge  17  or at the second edge  18 .  FIGS. 1B-1C  shows an embodiment comprising an embodiment of the tongue  3  which may be formed, e.g. by mechanically cutting, of a material of the panels. 
     Embodiments which comprise a tongue  3  at the first or the second edge and tongue groove  6  at the other of the first edge  17  or the second edge  18  for a locking in a second direction  11  may comprise an embodiment of the first angle  101  which may be in the range of about 90° to about °  145 , or in the range of about 100° to about 135°, or in the range of about 110° to about 125°, or about 120° and an embodiment of the second angle  102  which may in the range of about 80° to about 135°, or in the range of about 100° to about 115°, or about 110°. 
     As shown for example in  FIG. 5 , the embodiments shown in  FIGS. 1B-1C  and  FIG. 7  comprise a first locking surface  31  and a second locking surface  32  which are configured for a locking in a second direction  11  perpendicular to the first direction  12 . Embodiments of the first angle  101  may be in the range of about 70° to about 90°, or in the range of about 80° to about 89°, or in the range of about 85° to about 89°, and embodiments of the second angle  102  may be in the range of about 75° to about 85°, or in the range of about 80° to about 85°. 
       FIG. 2A  shows the embodiment shown in  FIG. 1A  during an illustrative assembling. The second edge  18  of the second panel  2  is being displaced in an assembly direction  10  relative of the first edge  17  of the first panel  1  to obtain a locked position of the first edge and the second edge. The assembly direction  10  may be perpendicular to the first panel surface  15 .  FIGS. 4A-4B  show the embodiment before assembling. 
     The flexible tongue may be compressed and/or displaced, during the assembling, in a direction  112  toward a bottom  9  of the insertion groove  8 . The flexible tongue is configured to spring back when the first edge  17  and the second edge  18  have reached the locked position. 
       FIG. 2B  shows the embodiment shown in  FIG. 1A  during an embodiment of the assembling. The embodiments shown in  FIGS. 1C and 7  may be assembled with the same method or a similar method. The second edge  18  of the second panel  2  is being displaced in an assembly direction  10  relative the first edge  17  of the first panel  1  to obtain a locked position of the first edge and the second edge. The assembly direction  10  may be perpendicular to the first panel surface  15 .  FIGS. 3A-3B  show the embodiment before assembling. 
     The locking element  5  may comprise a first guiding surface  20  at an outer surface and the locking groove  4  may comprise a second guiding surface  22  at an opening of the locking groove  4 . The first guiding surface  20  is configured to cooperate with the second guiding surface  22  during assembling to guide the locking element  5  into the locking groove  4 . 
       FIG. 5  shows that the size of the first guiding surface  20  may be greater than the size of the second guiding surface  22  which may have the effect that the guiding is improved. 
     The first guiding surface  20  may comprise an essentially planar surface. A planar surface can provide a greater guiding length. 
     The second guiding surface  22  may have a rounded shape. The rounded shape can provide a smaller contact surface between the first guiding surface  20  and the second guiding surface  22  during the assembling which may decrease the friction. 
     As shown for example in  FIG. 5 , a ratio between a length  21  of the planar surface and a radius R 1  of the rounded shape of the second guiding surface  22  may be in the range of about 2 to about 5, or about 3 to about 4. The ratio mentioned above can be large enough to allow for an effective guiding over a relative great guiding length but not too large which may result in a sharp edge at the second guiding surface  22  which may break during assembling or transportation. 
     A transition surface between the first locking surface  31  and the strip surface  36  may have a rounded shape. The transition surface may comprise a transition radius R 2 . The transition radius R 2  may be greater than the radius R 1  of the rounded shape of the second guiding surface which may have the effect that the locking strength is increased and cracks may be avoided at the transition surface during assembling and when a load in the first direction, e.g., from a force pulling apart the panels, is applied. 
     A relatively smaller radius R 1  of the of the rounded shape of the second guiding surface also has the effect that the cooperation part  104  is positioned closer to the strip surface  36  of the locking strip  19  which may have the effect that when a load is applied in the first direction, e.g., from a force pulling apart the panels, the load is absorbed at a part with a shorter moment arm. A shorter moment arm may have the advantage that the locking strength is increased. 
     The locking element  5  may be turned away in a direction  111  from the first edge  17  during the vertical displacement, and may spring back when the first edge and the second edge has reached the locked position. 
     As shown for example in  FIG. 2B , a side of the locking strip  19  at the second panel surface  16  may comprise a space  41 , such as a recess or bevel, under the locking element  5  which may facilitate turning of the locking  5  during the assembling. 
     The second edge  18  may be provided with a calibrating groove  25  adjacent said locking groove  4 . The calibrating groove  25  may compensate for floorboards having different thickness, especially any difference in thickness at the edges of the floorboards. The calibrating groove allows that the second edge may be pushed towards a sub-floor on which the floorboards are arranged. The calibrating groove  25  shown in  FIG. 2B  is of a rectangular shape, however the calibrating groove may have other shapes such as a bevel. 
     The assembling shown in  FIG. 2A-2B  may comprise a displacement which is parallel to the first direction. 
     The panels  1 ,  2  may comprise a polymer material or a wood based material. 
     As shown for example in  FIG. 3A , a distance  116  between the first panel surface  15  and the second panel surface  16  may be in the range of about 3 mm to about 15 mm, or in the range of about 5 mm to about 8 mm. 
     As shown for example in  FIG. 3B , a distance  117  between the third panel surface  13  and the fourth panel surface  14  may be in the range of about 3 mm to about 15 mm, or in the range of about 5 mm to about 8 mm. 
     The locking strip  19  may protrude beyond a first joint surface  37 , at the first edge  17 , which is adjacent the first panel surface  15 . 
     The second edge  18  may comprise a second joint surface  38  which is adjacent the third panel surface  13 . 
     The first joint surface  37  may be configured to cooperate with the second joint surface  38  for a locking in a direction which is opposite to the first direction  12 . 
     An edge surface  35  at the second edge may be configured to cooperate with the strip surface  36  for a locking in a direction which is opposite to the first direction  11 . The edge surface may be positioned on the same side of the second edge  18  as the fourth panel surface  14 . 
     The first locking surface  31  and/or the second locking surface  32  may be essentially plane surfaces. 
     The first panel surface  15  and the third panel surface  13  may comprises a decorative surface. 
     The first and the second panel may be building panels, such as floor panels, wall panels or ceiling panels. 
     The first and the second panel may be of a rectangular shape. 
     The first and the second panel may be building panels, such as floor panels, wall panels or ceiling panels. 
     The first edge and the second edge may be short edges of the first and the second panel. 
     The assembling may also comprise an angling motion along a long side of the first and or the second panel. 
     The embodiments described above may be resilient panels. The resilient panels may comprise a core comprising thermoplastic material. The thermoplastic material may be foamed. 
     The thermoplastic material may comprise polyvinyl chloride (PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate, methacrylate, polycarbonate, polyvinyl butyral, polybutylene terephthalate, or a combination thereof. The core may be formed of several layers. 
     The embodiments described above may comprise a decorative layer, such as a decorative foil comprising a thermoplastic material. The thermoplastic material of the decorative layer may be or comprise polyvinyl chloride (PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate, methacrylate, polycarbonate, polyvinyl butyral, polybutylene terephthalate, or a combination thereof. The decorative foil is preferably printed, for example by direct printing, rotogravure, or digital printing. 
     The embodiments described above may comprise a wear layer such as a film or foil. The wear layer may comprise thermoplastic material. The thermoplastic material may be polyvinyl chloride (PVC), polyester, polypropylene (PP), polyethylene (PE), polystyrene (PS), polyurethane (PU), polyethylene terephthalate (PET), polyacrylate, methacrylate, polycarbonate, polyvinyl butyral, polybutylene terephthalate, or a combination thereof. 
     The embodiments described above may comprise a wood base core, such as HDF, MDF or plywood. 
     Further embodiments of the disclosure are described below. 
     1. A set of panels comprising a first panel ( 1 ) and a second panel ( 2 ), wherein the first panel ( 1 ) comprising a first edge ( 17 ), a first panel surface ( 15 ) and a second opposite panel surface ( 16 ) and the second panel ( 2 ) comprises a second edge ( 18 ), a third panel surface ( 13 ) and an opposite fourth panel surface ( 14 ), wherein the first edge ( 17 ) comprises a locking strip ( 19 ) with a locking element ( 5 ) configured to cooperate with a locking groove ( 4 ) at the second edge ( 18 ) of the second panel ( 2 ) for locking the first edge ( 17 ) to the second edge ( 18 ) in a first direction ( 12 ) which is parallel to the first panel surface ( 15 ), wherein the first edge ( 17 ) is configured to be assembled to the second edge by a displacement of the second edge ( 18 ) relative the first edge ( 17 ) in an assembly direction ( 10 ), which is perpendicular to the first panel surface ( 15 ), to obtain a locked position of the first edge ( 17 ) and the second edge ( 18 ) wherein the locking element ( 5 ) comprises a first locking surface ( 31 ) at a first angle ( 101 ) from a plane parallel to the first panel surface ( 15 ) and the locking groove comprises a second locking surface ( 32 ) at a second angle ( 102 ) from a plane parallel to the third panel surface ( 13 ), wherein the first angle ( 101 ) is different from the second angle ( 102 ) such that the first locking surface ( 31 ) converges towards the second locking surface ( 32 ) at a cooperation part ( 104 ) in the locked position, and the first locking surface ( 31 ) cooperates with the second locking surface ( 32 ) at the cooperation part ( 104 ) for the locking in the first direction ( 12 ). 
     2. The set of panels as described in embodiment 1, wherein the cooperation part ( 104 ) is closer to a strip surface ( 36 ) of the locking strip ( 19 ) than to an outer surface ( 7 ) of the locking element ( 5 ). 
     3. The set of panels as described in embodiment 1 or 2, wherein there is a space  115  between the first locking surface ( 31 ) and the second locking surface ( 32 ) in the locked position, wherein the space is located between the cooperation part ( 104 ) and an outer surface ( 7 ) of the locking element ( 5 ). 
     4. The set of panels as described in any one of the embodiments 1-3, wherein the difference ( 103 ) between the first angle ( 101 ) and the second angle ( 102 ) is in the range of about 2° to about 15°, or in the range of about 5° to about 10°, or in the range of about 5° to about 7°, or about 7. 
     5. The set of panels as described in any one of the embodiments 1-4, wherein the cooperation part ( 104 ) is positioned at a first distance ( 113 ) from a strip surface ( 36 ) of the locking strip ( 19 ), wherein an outer surface ( 7 ) of the locking element ( 5 ) is positioned at a second distance ( 114 ) from a strip surface ( 36 ) of the locking strip ( 19 ), and wherein a ratio between the first distance ( 113 ) and the second distance ( 114 ) is in the range of about 0.03 to about 0.3, or in the range of about 0.1 to about 0.2, 03, or about 0.15. 
     6. The set of panels as described in any one of the embodiments 1-5, wherein one of the first edge ( 17 ) or the second edge ( 18 ) comprises a tongue ( 3 ) which is configured to cooperate with a tongue groove ( 6 ) at the other one of the first edge ( 17 ) or the second edge ( 18 ) for a locking in a second direction ( 11 ) which is perpendicular to the first direction ( 12 ). 
     7. The set of panels as described in embodiments 6, wherein the tongue ( 3 ) is a flexible tongue which is located in an insertion groove at the one of the first edge ( 17 ) or the second edge ( 18 ). 
     8. The set of panels as described in embodiment 6 or 7, wherein the first angle ( 101 ) is in the range of about 90° to about °  145 , or in the range of about 100° to about 135°, or in the range of about 110° to about 125°, or about 120° and wherein the second angle ( 102 ) is in the range of about 80° to about 135°, or in the range of about 100° to about 115°, or about 110°. 
     9. The set of panels as described in any one of the embodiments 1-8, wherein the first locking surface ( 31 ) and the second locking surface ( 32 ) are configured for a locking in a second direction ( 11 ) which is perpendicular to the first direction ( 12 ). 
     10. The set of panels as described in embodiments 9, wherein the first angle ( 101 ) is in the range of about 70° to about 90°, or in the range of about 80° to about 89°, or in the range of about 85° to about 89°, and wherein the second angle ( 102 ) is in the range of about 75° to about 85°, or in the range of about 80° to about 85°. 
     11. The set of panels as described in any one of the embodiments 1-10, wherein panels comprise a polymer material or a wood based material. 
     12. The set of panels as described in any one of the embodiments 1-11, wherein a distance between the first panel surface ( 15 ) and the second panel surface ( 16 ) is in the range of about 3 mm to about 15 mm, or in the range of about 5 mm to about 8 mm. 
     13. The set of panels as described in any one of the embodiments 1-12, wherein a distance between the third panel surface ( 13 ) and the fourth panel surface ( 14 ) is in the range of about 3 mm to about 15 mm, or in the range of about 5 mm to about 8 mm. 
     14. The set of panels as described in any one of the embodiments 1-13, wherein the first panel surface ( 15 ) and the third panel surface ( 13 ) comprise a decorative surface. 
     15. The set of panels as described in any one of the embodiments 1-14, wherein the first and the second panel are building panels, such as floor panels, wall panels or ceiling panels. 
     16. The set of panels as claimed in any one of the claims  1 - 15 , wherein the locking element ( 5 ) comprise a first guiding surface ( 20 ) at an outer surface and the locking groove ( 4 ) comprises a second guiding surface ( 22 ) at an opening of the locking groove ( 4 ), wherein the first guiding surface ( 20 ) is configured to cooperate with the second guiding surface ( 22 ) during assembling to guide the locking element ( 5 ) into the locking groove ( 4 ). 
     17. The set of panels as claimed in claim  16 , wherein the size of the first guiding surface ( 20 ) is greater than the size of the second guiding surface ( 22 ). 
     18. The set of panels as claimed in claim  16  or  17 , wherein the first guiding surface ( 20 ) comprises an essentially planar surface. 
     19. The set of panels as claimed in any one of the claims  16 - 18 , wherein the second guiding surface ( 22 ) has a rounded shape. 
     20. The set of panels as claimed in claim  16  or  17 , wherein the first guiding surface ( 20 ) comprises an essentially planar surface and the second guiding surface ( 22 ) has a rounded shape, wherein a ratio between a length ( 21 ) of the planar surface and a radius (R 1 ) of the rounded shape of the second guiding surface is in the range of about 1 to about 5, or about 2 to about 4, or about 3.