Patent Publication Number: US-2023147355-A1

Title: Subfloor joint

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. application Ser. No. 16/703,280, filed on Dec. 4, 2019, which claims the benefit of Swedish Application No. 1851511-4, filed on Dec. 5, 2018. The entire contents of each of U.S. application Ser. No. 16/703,280 and Swedish Application No. 1851511-4 are hereby incorporated herein by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     Embodiments of the present invention relate to subfloor panels comprising a joint. The panels are configured to be assembled on joists. The panels and the joists may be wood based. 
     BACKGROUND OF THE INVENTION 
     Subfloors are known comprising wood based panels, such as particle boards, comprising tongue and groove joints which are configured to be glued. 
     Embodiments of the present invention address a need to provide an improved subfloor and joint. 
     SUMMARY OF THE INVENTION 
     Accordingly, embodiments of the present invention preferably seek to mitigate, alleviate or eliminate one or more deficiencies, disadvantages or issues in the art, such as the above-identified, singly or in any combination by providing subfloor panels comprising a joint which enables a faster assembling of the subfloor panels. 
     A further object of embodiments of the invention is to provide subfloor panels with a joint with increased strength. 
     At least some of these and other objects and advantages that will be apparent from the description have been achieved by a first aspect of the invention including set of essentially identical subfloor panels comprising a joint configured to be glued, wherein the joint comprises a strip which protrudes from a first joint edge at an edge of a panel. The joint comprises an element groove at an underside of an adjacent edge of an adjacent panel and adjacent a second joint edge of the adjacent edge. The strip comprises an element which is configured to cooperate, in a joined position of the edge and the adjacent edge, with the element groove for positioning of the panel relative the adjacent panel in a first horizontal direction and the first joint edge is configured to cooperate with the second joint edge for positioning of the panel relative the adjacent panel in a second opposite horizontal direction. The joint comprises a flexible tongue at an outer part of the strip and a tongue groove below the element groove or a flexible tongue below the element groove and a tongue groove at an outer part of the strip. The flexible tongue is configured to cooperate, in the joined position, with the tongue groove for positioning of the panel relative the adjacent panel in a first vertical direction. The joint is configured for a joining of the edge and the adjacent edge by a vertical motion of the edge relative the adjacent edge. A space above the strip and between the element and the first joint edge is configured to be filled partly or completely with a glue before the edge and the adjacent edge are joined, and wherein the joint is configured such that during joining the glue is displaced in the joint and towards an upper surface of the panel and towards a lower surface of the panel. A flow resistance towards the lower surface is greater than a flow resistance towards the upper surface. 
     An advantage with the greater flow resistance towards the lower surface may be that the glue may be prevented from being displaced to the flexible tongue and the tongue groove which pay prevent a proper positioning of the panel relative the adjacent panel in a first vertical direction. A further advantage may be that the glue may be properly distributed in the joint and that a portion of the glue is displaced to the upper surface of the panel which may provide an accurate bonding of the joint when the glue has dried or hardened. 
     The set of panels and the joint may be configured to be joined on joists. 
     An element top surface of the element may be configured to cooperate, in the joined position, with a groove top surface of the locking groove for positioning of the panel relative the adjacent panel in a second vertical direction. 
     A first upper joint edge surface of the first joint edge may be configured to cooperate, in the joined position, with a second upper joint edge surface of the second joint edge for positioning of the panel relative the adjacent panel in a second opposite horizontal direction. 
     A third distance between the first upper joint edge surface and the second upper joint edge surface may be in the range of about 0.05 mm to about 0.3 mm, or in the range of about 0.1 mm to about 0.2 mm, or is about 0.15 mm. 
     The first joint edge may comprise a third lower joint edge surface, which is adjacent and below the first upper joint edge surface and the second joint edge may comprise a fourth lower joint edge surface, which is adjacent and below the second upper joint edge surface, wherein a fourth distance, in the joined position, between the third lower joint edge surface and fourth lower joint edge surface, may be greater than the third distance. 
     A cooperation area, in the joined position, between element top surface and the groove top surface may extend over a first distance and a cooperation area between the first upper joint edge surface and the second upper joint edge surface may extend over a second distance, wherein the first distance may be greater than the second distance. 
     A ratio between the first distance and the second distance may be in the range of about 1.2 to about 4, or about 1.5 to about 3, or is about 2. 
     An element side surface of the element may be configured to cooperate with an element groove side surface for positioning of the panel relative the adjacent panel in the first horizontal direction, wherein the element side surface and element groove side surface may be configured to prevent or reduce the amount of glue displaced towards the outer part of the strip. 
     The viscosity of the glue may be within the range of about 3000 CP to about 20,000 cP at 20 C°, about 5000 to about 15,000 cP at 20 C° or is about 10,000 cP at 20 C°. The viscosity may be tested according to the standards DIN EN ISO 2555 or DIN EN 12092. 
     The joint may comprise a lower surface adjacent the element groove which may be configured to be positioned, in a joined position, at a fifth distance from an upper surface of the strip, wherein the fifth distance may be in the range of about 0.2 mm to about 0.5 mm or preferably is about 0.3 mm. 
     The glue may include one or more of Poly vinyl acetate glue, MS polymer glue, Polyurethane glue, Urea-formaldehyde glue, silicone or thermoplastic rubber. 
     The panel and the adjacent panel may be wood based panels, such as particleboard, OSB, plywood, HDF or MDF. 
     A second aspect of the invention includes a set of essentially identical subfloor panels comprising a joint configured to be glued. The joint comprising a tongue at a first edge of a first panel and a tongue groove at a second edge of a second panel. The tongue and the tongue groove are configured for positioning of the first panel relative the second panel in a vertical direction. A lower lip of the tongue groove extends beyond an upper lip of the tongue groove. An element protrudes from the lower lip and an underside of the first edge comprising an element groove. The element and the element groove are configured for positioning of the first panel relative the second panel in a horizontal direction. An outer edge of the lower lip comprises a first impact surface, which is downward facing, and the first edge comprising a second impact surface, which is upward facing. The first impact surface is configured to cooperate with the second impact surface for partly absorbing a force applied at an upper surface of the first panel and/or at an upper surface of a second panel when the first and the second panel are joined by the joint and assembled on joists. 
     Thus, the joint solves the problem of positioning the first panel relative the second panel before the glue dries or cures and bonds the first panel to the second panel. 
     The impact surfaces may have the effect that the strength of the joint is improved. 
     A lower surface of the tongue may be configured to be positioned at a distance from an upper surface of the lower lip, in a joined position of the first and the second panel such that a glue space is obtained. 
     The glue space may extend essentially from the element to an outer part of the tongue. 
     The distance between the lower surface of the tongue and the upper surface of the lower lip may be in the range of about 0.2 mm to about 0.5 mm, preferably about 0.3 mm. 
     An angle between the second impact surface and a lower surface of the first panel may be in the range of about 40° to about 70°, preferably about 60°. 
     The first impact surface may be essentially parallel to the second impact surface. 
     The panels may be wood based panels, such as particleboard, OSB, plywood, HDF or MDF. 
     The first and the second panel may each comprise outer layers and a core layer, wherein the core layer comprises coarser particles than the outer layers, wherein the lower surface of the tongue and the upper surface of the lower lip is within the core layer, such that a stronger glue connection is obtained. 
     The first and the second panel may each comprise outer layers and a core layer, wherein the core layer comprises coarser particles than the outer layers, wherein an upper surface of the tongue is configured to be glued to a lower surface of the upper lip, wherein the upper surface of the tongue and lower surface of the upper lip, is within the core layer, such that a stronger glue connection is obtained. 
     The first impact surface and the second impact surface may be configured to be glued together. 
     The joint may be configured for a joining of the first edge and the second edge by an angling motion of the first panel relative the second panel. 
     The set of panels according to the first aspect may include the joint described in the second aspect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects, features and advantages of which embodiments of the invention are capable of, will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which 
         FIG.  1 A  shows in a 3D-view an embodiment of the set of subfloor panels according to an embodiment of the invention. 
         FIG.  1 B  shows in a top view an embodiment of a subfloor panel according to an embodiment of the invention. 
         FIG.  2    shows a crosscut in a side view of an embodiment of the set of subfloor panels during joining according to an embodiment of the invention. 
         FIG.  3    shows a crosscut in a side view of an embodiment of the set of subfloor panels in a joined position according to an embodiment of the invention. 
         FIG.  4    shows in a 3D-view an embodiment of the set of subfloor panels during joining on joists according to an embodiment of the invention. 
         FIG.  5 A- 5 B  show crosscuts in a side view of embodiments of the set of subfloor panels in a joined position according to embodiments of the invention. 
         FIGS.  6 A- 6 J  show embodiments of a flexible tongue according to embodiments of the invention. 
         FIG.  7    shows a crosscut in a side view of an embodiment of the set of subfloor panels in a joined position according to an embodiment of the invention. 
         FIG.  8    shows a crosscut in a side view of an embodiment of the set of subfloor panels in a joined position according to an embodiment of the invention. 
         FIG.  9 A- 9 B  show crosscuts during assembling in a side view of an embodiment of the set of subfloor panels according to an embodiment of the invention. 
         FIG.  10 A- 10 B  show crosscuts in a joined position in a side view of the embodiment shown in  FIG.  9 A- 9 B . 
         FIG.  10 C  shows a crosscut in a joined position in a side view of the embodiment shown in  FIG.  9 A- 9 B  with an alternative arrangement of the displaceable tongue. 
         FIGS.  11 A- 11 B  show crosscuts in a joined position in a side view of an embodiment of the set of subfloor panels according to embodiments of the invention. 
         FIGS.  12 A- 12 B  show crosscuts in a joined position in a side view of an embodiment of the set of subfloor panels according to embodiments of the invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Specific embodiments of the invention 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 invention 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. 
     An embodiment of the invention is shown in  FIG.  1 A  in a 3D-view during assembling of a set of subfloor panels. The subfloor panels are essentially identical. An embodiment of a panel  1  in the set is shown in  FIG.  1 B . The panel  1  is of a rectangular shape and comprises first edge  5   a  and an opposite second edge  5   b . The panel  1  further comprise a third edge  4   a  and an opposite fourth edge  4   b  which extend between the first edge  5   a  and the opposite second edge  5   b . The first and the second edge may be long edges and the third and the forth edges may be short edges. The panel  1  comprises an upper surface  41  and at least two opposite edges comprise a joint for joining the panel  1  to an adjacent panel.  FIG.  1 A  shows that a first edge  5   a  of a first panel  1 ′ may be joined to a second edge  5   b  of a second panel  1 ″ by an angling motion  50  and a third edge  4   a  of the first panel  1 ′ may be joined by the same angling motion to a fourth edge  4   b  of a third panel  1 . The motion to join the third edge  4   a  and the fourth edge  4   b  may be referred to as a folding motion. 
       FIG.  2    shows a crosscut in a side view of an embodiment of the set of subfloor panels during joining and  FIG.  3    the embodiment in a joined position. The set comprises a joint configured to be glued. The joint comprises a tongue  13  at a first edge  5   a  of a first panel  1 ′ and a tongue groove  10  at a second edge  5   b  of a second panel  1 ″. The tongue  13  and the tongue groove  10  are configured for positioning of the first panel  1 ′ relative the second panel  1 ″ in a vertical direction. A lower lip  16  of the tongue groove  10  extend beyond an upper lip  11  of the tongue groove  10 . An element  12  protrudes from the lower lip  16  and an underside of the first edge  5   a  comprises an element groove  14 , wherein the element and the element groove are configured for positioning of the first panel  1 ′ relative the second panel  1 ″ in a horizontal direction. An outer edge of the lower lip  16  comprises a first impact surface  22 , which is downward facing, and the first edge  5   a  comprises a second impact surface  21 , which is upward facing. The first impact surface  22  is configured to cooperate with the second impact surface  21  for partly absorbing a force F applied at an upper surface  41 ′ of the first panel  1 ′ and/or at an upper surface  41 ″ of the second panel  1 ″ when the first and the second panel are joined by the joint and assembled on joists  71 ,  71 ′ as shown in  FIG.  4   . 
       FIG.  2    shows that glue  17 ,  17 ′ may be applied on an upper surface  39  of the tongue  13  and on an upper surface  18  of the lower lip  16  before the first and the second panel are joined. Furthermore, glue may be applied on the first impact surface  22  and/or on the second impact surface  21  (not shown) before the first and the second panel are joined. The glue is during the joining distributed in parts of the joint. A portion  31  of the glue  17 ,  17 ′ may be positioned, in the joined positioned, at the upper surface  41 ′ of the first panel  1 ′ and/or second panel. That portion of the glue is preferably removed before the glue has dried or hardened. 
     The glue  17 ′ applied on the upper surface  39  of the tongue  13  may be distributed from an inner part  32  at the tip of the tongue  13  to an outer part  31  at the upper surface  41 ′ of the first panel  1 ′ and/or second panel  1 ″. The glue may be applied along essentially the entire length of the edge. 
     The joint may comprise a first joint surface  37  at the first edge  5   a  and an opposite second joint surface  36  at the second edge  5   b . The first joint surface  37  extends from the upper surface  41 ′ of the first panel  1 ′ towards the tongue  13 . The second joint surface  36  extends from the upper surface  41 ″ of the second panel  1 ″ towards the tongue groove  10 . The first joint surface  37  and the opposite second joint surface  36  are configured to be glued to each other. The glue  17 ′ applied on the upper surface  39  of the tongue  13  may be distributed between the first joint surface  37  and the opposite second joint surface  36 . 
     A distance  46  between the first joint surface  37  and the second joint surface  36  may be in the range of about 0.05 mm to about 0.3 mm, or in the range of about 0.1 mm to about 0.2 mm, or about 0.15 mm. 
     The glue  17  applied on the upper surface  18  of the lower lip  16  may be distributed from an inner part  33  at the tip of the tongue  13  to an outer part  34  at the element  12 . 
     The glue may be a resin, preferably cross-linked, hot melt glue, white glue or glue comprising polyvinyl acetate or polyurethane. 
     A lower surface  19  of the tongue  13  may be configured to be positioned at a distance  44  from an upper surface  18  of the lower lip  16 , in a joined position of the first and the second panel  1 ′,  1 ″, such that a glue space is obtained. The glue space may extend essentially from the element  12  to an outer part of the tongue  13 . The distance  44  between the lower surface  19  of the tongue  13  and the upper surface  18  of the lower lip  16 , may be in the range of about 0.2 mm to about 0.5 mm, preferably about 0.3 mm. 
     A distance between the upper surface  39  of the tongue  13  and the lower surface  38  of the upper lip  11 , may be shorter than the distance  44  between the lower surface  19  of the tongue  13  and the upper surface  18  of the lower lip  16 . 
     An angle  43  between the second impact surface and a lower surface  42 ′ of the first panel  1 ′ may be in the range of about 40° to about 70°, preferably about 60°. 
     The first impact surface  22  may be essentially parallel to the second impact surface  21 . 
     The first impact surface  22  and the second impact surface  21  may have a planar and/or curved shape. 
     The first impact surface  22  and the second impact surface  21  may have the same shape. 
     A distance  45  between the first impact surface  22  and the second impact surface  21  may be in the range of about 0.05 mm to about 0.3 mm, or in the range of about 0.1 mm to about 0.2 mm, or about 0.15 mm. 
     The panels may be wood based panels, such as particleboard, OSB, plywood, HDF or MDF. 
       FIG.  8    shows that the first and the second panel  1 ′,  1 ″ each may comprise outer layers  82 ,  83  and a core layer  81 , wherein the core layer  81  comprises coarser particles than the outer layers, wherein the lower surface  19  of the tongue and the upper surface  18  of the lower lip  16  is within the core layer, such that a stronger glue connection is obtained. 
     An upper surface  39  of the tongue  13  is configured to be glued to a lower surface  38  of the upper lip  11 , wherein the upper surface  39  of the tongue  13  and lower surface  38  of the upper lip  11 , is within the core layer  81 , such that a stronger glue connection is obtained. 
     The first impact surface  22  may be configured to be glued to the second impact surface  21 . The first impact surface  22  and the second impact surface  21  may be positioned at least partly in the core layer  81 . The glue  17 ″ between the first impact surface  22  and the second impact surface  21  may be distributed from a lower portion  84  at the lower surface  42 ′,  42 ″ of the first and the second panel, respectively, to an upper portion  85  adjacent an upper surface of the element groove  14 . 
     Each of the panels may comprise a decorative layer attached to at least one of said outer layers. 
       FIG.  4    shows an embodiment of the first panel  1 ′, the second panel  1 ″ and the third panel  1  during assembling on joists  71 ,  71 ′,  71 ″,  71 ′″. The first panel  1 ′, the second panel  1 ″ and the third panel  1  may be glued also to the joists  71 ,  71 ′,  71 ″,  71 ′″. The joists  71 ,  71 ′,  71 ″,  71 ′″ may be wood based. The first panel  1 ′, the second panel  1 ″ and the third panel  1  may be identical. 
       FIG.  5 A  shows an embodiment of the joint for joining a third edge of the first panel  1 ′ to a fourth edge of a third panel  1 . The joint may comprise a flexible tongue  30  at the fourth edge configured to cooperate with a tongue groove  20  at a third edge for positioning of the first panel  1 ′ relative the third panel  1  in a vertical direction. The flexible tongue  30  may be positioned in a displacement groove  40 . The flexible tongue may be configured to be compressed during assembling and spring back towards and partly into the tongue groove  20 . The joint may comprise a strip  6  that protrudes from the fourth edge. An outer part of the strip  6  may comprise an element  7  and an underside of the third edge may comprise an element groove  8 , wherein the element and the element groove are configured for positioning of the first panel  1 ′ relative the third panel  1  in a horizontal direction.  FIG.  5 B  shows an embodiment of the joint comprising an embodiment of the displacement groove  40  which extend in an angled direction relative an upper surface of the third panel. The angle may be from about 5 degrees to about 30 degrees, for examples from about 10 to about 20 degrees. The joint is shown in a joined position. Glue may be applied in the joint before fourth edge and the third edge are joined. 
     Embodiments of the flexible tongue  30 , which is displaceable in the insertion groove  20 , are shown in  FIGS.  6 A- 6 D .  FIGS.  6 A- 6 B  show the flexible tongue  30  in a joined position and  FIGS.  6 C- 6 D  show the flexible tongue  30  during assembling of a panel and an adjacent panel.  FIG.  6 B  shows a cross section of the flexible tongue  30  in  FIG.  6 A , which shows a top view.  FIG.  6 D  shows a cross section of the flexile tongue  30  in  FIG.  6 C , which shows a top view. The flexible tongue  30  comprises bendable protruding parts  64 . A space  63  is provided between the flexible tongue  30  and a bottom wall of the insertion groove  40 .  FIG.  6 C  shows that the flexible tongue  30  is pushed into the insertion groove  40  and towards the bottom wall of the insertion groove  40  during an assembly of a panel with an adjacent panel. The flexible tongue  30  springs back towards its initial position when the panel has reached a joined position. A recess  65  is preferably arranged at each bendable protruding part. 
     The flexible tongue  30  may have a first displacement surface  66  and an opposite second displacement surface  67 , configured to be displaced along a third displacement surface  68  and a fourth displacement surface  69 , respectively, of the insertion groove  40 . 
     Another embodiment of the flexible tongue  30 , without the protruding bendable parts  64 , is shown in  FIGS.  6 E- 6 F .  FIG.  6 F  shows a cross section of the flexible tongue  30  shown in  FIG.  6 E , which shows a top view. The alternative embodiment is bendable in the length direction of the flexible tongue  30  in order to accomplish a similar function as the embodiment shown in  FIGS.  6 A- 6 D . 
     Another embodiment of the flexible tongue  30  is shown in  FIG.  6 G  in a top view. The tongue  30  comprises an inner part  88  and an outer part  89 . The inner part  88  and the outer part  89  are preferably made of two different materials, wherein the inner part  88  is more flexible than the outer part  89 . The inner part  88  is configured to be inserted into the insertion groove  40  and the outer part  89  is configured to extend into the tongue groove  20 . 
       FIGS.  6 G- 6 J  show in cross section embodiments of the tongue  30  comprising an inner part  91  and a pivoting outer part  92 . The inner part  91  is configured to be inserted into the insertion groove  40  and the outer part  92  is configured to extend into the tongue groove  20  and pivot during assembly of a panel and an adjacent panel. The embodiments in  FIGS.  6 H- 61    are preferably produced in one material, such as a polymer, by extruding. The embodiment in  FIG.  6 J  is preferably produced by coextruding and comprises at least two different polymer materials. The embodiment comprises a hinge portion  93  which connects the inner part  91  and the outer part  92 . The material of the hinge portion  93  is preferably more flexible than the inner part  91  and the outer part  93 . 
       FIG.  7    shows a crosscut in a side view of an embodiment of the set of subfloor in a joined position. The set comprises a joint configured to be glued. The joint comprises at the first edge a third impact surface  73 , which is downward facing, and the second edge comprising a fourth impact surface  74 , which is upward facing. The third impact surface  73  is configured to cooperate with the fourth impact surface  74  for partly absorbing a force F applied at an upper surface  41 ′ of the first panel when the first and the second panel are joined by the joint and assembled on joists  71 ,  71 ′ as shown in  FIG.  4   . The third impact surface  73  may be positioned between the upper surface  39  of the tongue  13  and the first joint surface  37 . The fourth impact surface  74  may be positioned between the upper surface  39  of the tongue  13  and the second joint surface  36 . 
       FIGS.  9 A- 9 B  show crosscuts during assembling in a side view of an embodiment of the set of subfloor panels and  FIGS.  10 A- 10 B  show crosscuts in a joined position in a side view of the embodiment shown in  FIGS.  9 A- 9 B . The embodiment includes a set of essentially identical subfloor panels  1 ,  1 ′ comprising a joint configured to be glued, wherein the joint comprises a strip  6  which protrudes from a first joint edge  132  at an edge of a panel  1 . The joint comprises an element groove  8  at an underside of an adjacent edge of an adjacent panel  1 ′ and adjacent a second joint edge  131  of the adjacent edge. The strip  6  comprise an element  7  which is configured to cooperate, in a joined position of the edge and the adjacent edge, with the element groove  8  for positioning of the panel  1  relative the adjacent panel  1 ′ in a first horizontal direction and the first joint edge  132  is configured to cooperate with the second joint edge  131  for positioning of the panel  1  relative the adjacent panel  1 ′ in a second opposite horizontal direction. The joint may comprise, as shown in  FIG.  10 C , a flexible tongue  30  at an outer part of the strip  6  and a tongue groove  20  below the element groove  8  or, as shown in  FIGS.  10 A- 10 B  a flexible tongue  30  below the element groove  8  and a tongue groove  20  at an outer part of the strip. The flexible tongue  30  is configured to cooperate, in the joined position, with the tongue groove  20  for positioning of the panel  1  relative the adjacent panel  1 ′ in a first vertical direction. 
     A space above the strip  6  and between the element  7  and the first joint edge  132  is configured to be filled partly or completely with a glue before the edge and the adjacent edge are joined, and wherein the joint is configured such that during joining the glue is displaced in the joint and towards  111  an upper surface  41  of the panel and towards  112  a lower surface  42  of the panel. A flow resistance towards the lower surface  42  is greater than a flow resistance towards the upper surface  41 . 
     The joint is configured for a joining of the edge and the adjacent edge by a vertical motion  113  of the adjacent edge relative the edge. 
     The glue  17  may be applied on an upper surface  120  of the strip  6  before the edge and the adjacent edge are joined. The glue is during the joining distributed in parts of the joint. A portion  31  of the glue may be positioned, in the joined positioned, at the upper surface  41 , 41 ′ of the panel  1  and/or the adjacent panel  1 ′. The portion  31  of the glue  17  may indicate that the glue is properly distributed in the joint and may provide a proper seal of the joint at the upper surface  41 ′. The portion  31  of the glue  17  is preferably removed before the glue has dried or hardened. 
     The joint may be configured such that the displacement of the glue during the joining is discontinued before the glue reaches the flexible tongue  30  and the tongue groove  20 . The displacement of the glue may be discounted at an upper part of the element  7 . 
     The joint may comprise an insertion groove  40  and the flexible tongue may be positioned in the insertion groove  40 . The flexible tongue  30  may be displaceable in the insertion groove  40 . Embodiments of the flexible tongue  30  are shown in  FIGS.  6 A- 6 J  and described above. It may be an advantage that the glue is prevented from reaching the flexible tongue and the tongue groove since glue in the insertion groove  40  and or tongue groove may prevent a correct positioning of the panel  1  relative the adjacent panel  1 ′ in the first vertical direction. 
     An element top surface  107  of the element  7  may be configured to cooperate, in the joined position, with a groove top surface  108  of the locking groove  8  for positioning of the panel  1  relative the adjacent panel  1 ′ in a second vertical direction. 
     A first upper joint edge surface  102  of the first joint edge  132  may be configured to cooperate, in the joined position, with a second upper joint edge surface  101  of the second joint edge  131  for positioning of the panel  1  relative the adjacent panel  1 ′ in a second opposite horizontal direction. 
     In the joined position, a third distance  115  between the first upper joint edge surface  102  and the second upper joint edge surface  101  may be in the range of about 0.05 mm to about 0.3 mm, or in the range of about 0.1 mm to about 0.2 mm, or is about 0.15 mm. 
     The first joint edge  132  may comprise a third lower joint edge surface  122 , which is adjacent and below the first upper joint edge surface  102  and the second joint edge  131  may comprise a fourth lower joint edge surface  121 , which is adjacent and below the second upper joint edge surface  101 . A fourth distance  117 , in the joined position, between the third lower joint edge surface  122  and fourth lower joint edge surface  12  may be greater than the third distance  115  which may reduce the flow resistance towards the upper surface  41 . 
     A cooperation area, such as a first cooperation area  142 , in the joined position, between element top surface  107  and the groove top surface  108  may extend over a first distance  106  and a cooperation area, such as a second cooperation area  142 ′, between the first upper joint edge surface  102  and the second upper joint edge surface  101  may extend over a second distance  105 , wherein the first distance  106  may be greater than the second distance  105  which may provide a greater flow resistance towards the lower surface  42  than the flow resistance towards the upper surface  41 . 
     A ratio between the first distance  106  and the second distance  105  may be in the range of about 1.2 to about 4, or about 1.5 to about 3, or is about 2. 
     An element side surface  103  of the element  7  may be configured to cooperate with an element groove side surface  104  for positioning of the panel  1  relative the adjacent panel  1 ′ in the first horizontal direction, wherein the element side surface  103  and element groove side surface  104  may be configured to prevent or reduce the amount of glue displaced towards the outer part of the strip  6 . 
     The viscosity of the glue may be within the range of about 3000 CP to about 20,000 cP at 20 C°, about 5000 to about 15,000 cP at 20 C° or is about 10,000 cP at 20 C°. 
     The joint may comprise a lower surface  119  adjacent the element groove  8  which may be configured to be positioned, in a joined position, at a fifth distance  116  from an upper surface  120  of the strip  6 , wherein the fifth distance preferably is in the range of about 0.2 mm to about 0.5 mm or preferably is about 0.3 mm 
     The glue may include one or more of Poly vinyl acetate glue, MS polymer glue, Polyurethane glue, Urea-formaldehyde glue, silicone or thermoplastic rubber. 
     The panel  1  and the adjacent panel  1 ′ may be wood based panels, such as particleboard, OSB, plywood, HDF or MDF. 
     The panel and the adjacent panel  1 ,  1 ′ may each comprises outer layers and a core layer, wherein the core layer comprises coarser particles than the outer layers, wherein the upper surface of the strip may be within the core layer such that a stronger glue connection is obtained. 
     The panel  1  and the adjacent panel  1 ′ and the joint may be configured to be joined on joists  71  as shown in  FIG.  4   . 
     The panels may be installed by the folding motion shown in  FIG.  1 A  and described above, wherein the edge correspond to the fourth edge  4   a  and the adjacent edge corresponds to the third edge  4   b . The panel  1 , which correspond to the third panel  1 , and the adjacent panel  1 ′, which corresponds to the first panel  1 ′, are installed in a row and may be installed to another panel  1 ″, which correspond to the second panel″, in another row. 
       FIGS.  11  and  12    show embodiments preferably comprising the features of the embodiments explained in the above in relation to  FIGS.  9 A to  10 B . In addition to the said features, as shown in  FIGS.  11  and  12   , an outer part of the strip  6  may comprise a second element  7 ′ and an underside of the third edge may comprise a second element groove  8 ′, wherein the second element  7 ′ and the second element groove  8 ′ may be configured for positioning of the first panel  1 ′ relative the third panel  1  in a horizontal direction. 
     The joint of  FIGS.  11 A- 12 B  are configured for a joining of the edge of the first panel  1  and the adjacent edge of the adjacent panel  1 ′ by a vertical motion  113  of the edge relative the adjacent edge as explained in relation e.g. to  FIGS.  9 A- 9 B and  10 A- 10 B . 
     The second element  7 ′ may be configured to cooperate, in a joined position of the edge and the adjacent edge, with the second element groove  8  for positioning of the panel  1  relative the adjacent panel  1 ′ in a first horizontal direction, the second element groove  8 ′ may be configured to receive the second element  7 ′, and the first joint edge  132  is configured to cooperate with the second joint edge  131  for positioning of the panel  1  relative the adjacent panel  1 ′ in a second opposite horizontal direction. 
     The second element  7 ′ may be positioned vertically below the first element  7 . 
     The second element  7 ′ may be positioned outboard of and vertically below the first element  7 . 
     The displaceable tongue  30  may be positioned vertically between the first element  7  and the second element  7 ′ as shown in  FIGS.  11 A- 11 B . 
     The displaceable tongue  30  may be configured to translate, preferably linearly translate, inside the displacement groove  40  and along a lower surface of the displacement groove  40 . 
     The second element groove  8 ′ may be positioned vertically below the first element groove  8 . 
     The second element groove  8 ′ may be positioned outboard of and vertically below the first element groove  8 . 
     The tongue groove  40  may be positioned vertically between the first element groove  8  and the second element groove  8 ′ in  FIGS.  11 A- 11 B . 
     The displaceable tongue  30  may be positioned outboard a third cooperation area  142 ″ in joint position, as shown in  FIGS.  12 A- 12 B . 
     The lower surface of the displacement groove  40  may be inclined upwards, in a direction towards an opening of the displacement groove  40 , in relation to the back surface of the panel, i.e. towards the plane of the upper surface  41 , as shown in  FIGS.  11 A and  12 A . 
     The lower surface of the displacement groove  40  may be inclined downwards, in a direction towards an opening of the displacement groove  40 , in relation to the back surface of the panel, i.e. towards the plane of the back surface  42 , as shown in  FIGS.  11 B and  12 B . 
     The displaceable tongue  30  may be positioned at an outermost portion of the strip  6 , preferably at a position vertically below the first and second elements  7 ,  7 ′, as shown in  FIG.  12 A . 
     The tongue groove  20  may be positioned at an outermost portion of the strip  6 , preferably at a position vertically below the first and second elements  7 ,  7 ′, as shown in  FIG.  12 B . 
     The provision of a second element  7 ′ and a second element groove  8 ′ may facilitate improved resistance to relative rotation between the panel  1  and the adjacent panel  1 ′, such as bending of the joint, in response to a vertical force F applied to the joint and/or the first panel  1  and/or the adjacent panel  1 ′. A joint with improved resistance to water penetration may thus be achieved. 
     The displaceable tongue  30  may be arranged in the edge comprising the first and second elements  7 ,  7 ′ as shown in  FIGS.  11 A and  12 A  or in the edge comprising the first and second element groove  8 ,  8 ′ as shown in  FIGS.  11 B and  12 B . Thus, in the embodiments shown in  FIGS.  11 B and  12 B , the displaceable tongue  30  is configured in the second joint edge  131  of the falling panel, i.e. the adjacent panel  1 ′ configured to make the said vertical motion in relation to the first joint edge  132  of panel  1 . 
     A second element top surface  107 ′ of the second element  7 ′ may be configured to cooperate, in the joined position, with a second groove top surface  108 ′ of the second locking groove  8  for positioning of the panel  1  relative the adjacent panel  1 ′ in a second vertical direction. 
     A third cooperation area  142 ″ is formed, in the joined position, between the second element top surface  107 ′ and the second groove top surface  108 ′. 
     The third cooperation area  142 ″ above the strip  6  and between the second element  7 ′ and the first element  7  may be configured to be filled partly or completely with a glue before the edge and the adjacent edge are joined, the second element top surface  107 ′ of the second element  7 ′ may be configured to cooperate, in the joined position, with a second groove top surface  108 ′ of the second locking groove  8  to displace the glue in the joint towards  111 ′ an upper surface  41  of the panel and towards  112 ′ a lower surface  42  of the panel, for example the second element top surface  107 ′ and the second element groove top surface  108 ′ may be configured to become arranged in close proximity of each other or in abutment with each other in joined position. 
     The viscosity of the glue may be within the range of about 3000 CP to about 20,000 cP at 20 C°, about 5000 to about 15,000 cP at 20 C° or is about 10,000 cP at 20 C°. 
     The glue may include one or more of Poly vinyl acetate glue, MS polymer glue, Polyurethane glue, Urea-formaldehyde glue, silicone or thermoplastic rubber. 
     A second element side surface  103 ′ of the second element  7 ′ may be configured to cooperate with a second element groove side surface  104 ′ for positioning of the panel  1  relative the adjacent panel  1 ′ in the first horizontal direction, wherein the second element side surface  103 ′ and second element groove side surface  104 ′ may be configured to adapt the amount of glue displaced towards the outer part of the strip  6 . 
     When the word “about” or “essentially” is used in this specification in connection with a numerical value, it is intended that the associated numerical value include a tolerance of +/−10% around the stated numerical value. 
     Items 
     ITEM 1. A set of essentially identical subfloor panels  1 ,  1 ′,  1 ″ comprising a joint configured to be glued, wherein the joint comprises a strip  6  which protrudes from a first joint edge  132  at an edge of a panel  1 ,
         wherein the joint comprises an element groove  8  at an underside of an adjacent edge of an adjacent panel  1 ′ and adjacent a second joint edge  131  of the adjacent edge,   wherein the strip  6  comprise an element  7  which is configured to cooperate, in a joined position of the edge and the adjacent edge, with the element groove  8  for positioning of the panel  1  relative the adjacent panel  1 ′ in a first horizontal direction and the first joint edge  132  is configured to cooperate with the second joint edge  131  for positioning of the panel  1  relative the adjacent panel  1 ′ in a second opposite horizontal direction,   wherein the joint comprises a flexible tongue  30  at an outer part of the strip  6  and a tongue groove  20  below the element groove  8  or a flexible tongue  30  below the element groove  8  and a tongue groove  20  at an outer part of the strip  6 ,   wherein the flexible tongue  30  is configured to cooperate, in the joined position, with the tongue groove  20  for positioning of the panel  1  relative the adjacent panel  1 ′ in a first vertical direction,   wherein the joint is configured for a joining of the edge and the adjacent edge by a vertical motion  113  of the edge relative the adjacent edge,   wherein a space above the strip  6  and between the element  7  and the first joint edge  132  is configured to be filled partly or completely with a glue before the edge and the adjacent edge are joined, and wherein the joint is configured such that during joining the glue is displaced in the joint and towards an upper surface  41  of the panel and towards a lower surface  42  of the panel, and   wherein a flow resistance towards the lower surface  42  is larger than a flow resistance towards the upper surface  41 .       

     ITEM 2. The set as in item 1, wherein an element top surface  107  of the element  7  is configured to cooperate, in the joined position, with a groove top surface  108  of the locking groove  8  for positioning of the panel  1  relative the adjacent panel  1 ′ in a second vertical direction. 
     ITEM 3. The set as in item 1 or 2, wherein a first upper joint edge surface  102  of the first joint edge  132  is configured to cooperate, in the joined position, with a second upper joint edge surface  101  of the second joint edge  131  for positioning of the panel  1  relative the adjacent panel  1 ′ in a second opposite horizontal direction. 
     ITEM 4. The set as in item 3, wherein, in the joined position, a third distance  115  between the first upper joint edge surface  102  and the second upper joint edge surface  101  is in the range of about 0.05 mm to about 0.3 mm, or in the range of about 0.1 mm to about 0.2 mm, or is about 0.15 mm. 
     ITEM 5. The set as in item 3 or 4, wherein the first joint edge  132  comprises third lower joint edge surface  122 , which is adjacent and below the first upper joint edge surface  102  and the second joint edge  131  comprises a fourth lower joint edge surface  121 , which is adjacent and below the second upper joint edge surface  101 , wherein a fourth distance  117 , in the joined position, between the third lower joint edge surface  122  and fourth lower joint edge surface  121 , is greater than the third distance  115 . 
     ITEM 6. The set as in any one of the preceding items 2-5, wherein a cooperation area, in the joined position, between element top surface  107  and the groove top surface  108  extends over a first distance  106  and a cooperation area between the first upper joint edge surface  102  and the second upper joint edge surface  101  extends over a second distance  105 , wherein the first distance  106  is greater than the second distance  105 . 
     ITEM 7. The set as in any one of the preceding items, wherein an element side surface  103  of the element  7  is configured to cooperate with an element groove side surface  104  for positioning of the panel  1  relative the adjacent panel  1 ′ in the first horizontal direction, wherein the element side surface  103  and element groove side surface  104  are configured to prevent or reduce the amount of glue displaced towards the outer part of the strip  6 . 
     ITEM 8. The set as in any one of the preceding items, wherein the viscosity of the glue is within the range of about 3000 CP to about 20,000 cP at 20 C°, about 5000 to about 15,000 cP at 20 C° or is about 10,000 cP at 20 C°. 
     ITEM 9. The set as in any one of the preceding items, wherein the joint comprises a lower surface  119  adjacent the element groove  8  which is configured to be positioned, in a joined position, at a fifth distance  116  from an upper surface  120  of the strip  6 , wherein the fifth distance preferably is in the range of about 0.2 mm to about 0.5 mm or preferably is about 0.3 mm 
     ITEM 10. The set as in any one of the preceding items, wherein the glue includes one or more of Poly vinyl acetate glue, MS polymer glue, Polyurethane glue, Urea-formaldehyde glue, silicone or thermoplastic rubber. 
     ITEM 11. The set as in any one of the preceding items, wherein the panel  1  and the adjacent panel  1 ′ are wood based panels, such as particleboard, OSB, plywood, HDF or MDF. 
     ITEM 12. The set as in any one of the preceding items, wherein an outer part of the strip  6  comprises a second element  7 ′ and an underside of the third edge  4   a  of the adjacent panel  1 ′ comprises a second element groove  8 ′, preferably the second element  7 ′ and the second element groove  8 ′ are configured for positioning of the first panel  1 ′ relative the adjacent panel ( 1 ) in a horizontal direction. 
     ITEM 13. The set as in item 12, wherein a third cooperation area  142 ″ is formed above the strip  6  and between the second element  7 ′ and the first element  7 . 
     ITEM 14. The set as in item 13, wherein the third cooperation area  142 ″ is configured to be filled partly or completely with a glue before the edge and the adjacent edge are joined. 
     ITEM 15. The set as in any one of the preceding items 12 to 14, wherein the second element top surface  107 ′ of the second element  7 ′ is configured to cooperate, in the joined position, with a second groove top surface  108 ′ of the second locking groove  8  to displace the glue in the joint towards  111 ′ an upper surface  41  of the panel and towards  112 ′ a lower surface  42  of the panel.