Patent Publication Number: US-2007094985-A1

Title: Connecting element

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to a connecting element for connecting flooring panels with a core of wooden material, in particular MDF or HDF, which is provided with a tongue on one side edge and with a groove on the opposite side edge, and the tongue corresponds to the groove of the panel and the groove corresponds to the tongue of the panel, whereby two lips lying opposite one another are embodied on the top side projecting beyond the side edges.  
      2. Discussion of Background Information  
      A connecting element for connecting flooring panels is known, e.g., from DE 101 62 275 C1. The connecting element is embodied in a strip-like manner and is connected to the groove of the panel via a tongue or to the tongue of the panel via a groove.  
      The top side of the connecting element is flush with the top side of the panel. It can be shaped differently and in cross section can have convex, concave or V-shaped surface contours. In the connection of connecting element and flooring panel, a butt joint results between the panel edge and the edge of the connecting element. Through these butt joints, very narrow vertically directed gaps invisible to the naked eye form between the panel edges and the edges of the connecting element. This fact is a particular drawback, particularly with damp mopping of a floor, since the butt joint acts like a capillary that draws in the moisture between the panel and the connecting element.  
      Flooring panels are mainly composed of wooden materials, such as, e.g., HDF/MDF or OSB. Since moisture can penetrate into the wooden material core of the flooring panels due to the capillary effect, the side edges affected of the panels swell and form an overhang visible in the surface, a so-called “projection”. The quality of the floor is considerable impaired by this projection.  
     SUMMARY OF THE INVENTION  
      On the basis of this problem, the connecting element described at the outset is to be improved such that the swelling of the side edges of connected flooring panels is prevented.  
      To solve the problem a generic connecting element includes two lips lying opposite one another on the top side projecting beyond the side edges are formed.  
      Through this embodiment the butt joints forming in the connection of connecting element and flooring panel are overlapped, whereby a waterproof cover is advantageously formed between the adjacent side edges of connecting element and panel. To ensure the waterproofness, the overlapping lips have sufficient inherent elasticity that forces the outer lip end against the top side of the panel or the top side of the pattern. The top side of the flooring panel is thereby provided with a decorative surface that can imitate a natural material and protects the core material from damage, e.g., by moisture or abrasion.  
      A flocking can be advantageously provided on the underside of the overlapping lips in order to further increase the sealing effect of the lips. Advantageously, the flock fibers are arranged vertically on the support surface, i.e., the underside of the overlapping lips, in order to ensure an improved protection from the penetration of moisture into the connection from above via a correspondingly dense arrangement of fibers per unit area.  
      The connecting elements can be produced from a material mixture of wood fibers and plastic. In this manner, cost-effective connecting elements can be produced that have wood-like properties due to the proportion of wood fibers. The connecting elements can be produced as an extrusion profile in a continuous operation, whereby expediently the flocking of the underside of the overlapping lips likewise takes place in a continuous operation, utilizing the thermal energy inherent in the connecting element at the end of the extrusion. A separate adhesive layer for the deep connection of the connecting element and flocking fiber can thus be omitted. Preferably the connecting elements can also be made entirely of plastic. Color pigments can be added to the material of the connecting elements in order to color the connecting element and thus to adapt it accordingly to different requirements regarding the pattern of the panels.  
      The lips are preferably embodied to be elastically resilient so that the best possible seal of the butt joints between the connecting element and panels can be achieved. To this end, it is necessary in the connection of two panels for the lips to bear on the top side of the panels in a sealing manner. In this manner, water can be prevented from penetrating into the butt joints between the connecting element and panels during the damp mopping of the floor thus leading to a swelling of the floor and to projections.  
      Mechanical locking mechanisms can be provided in the area of the groove and the tongue of the connecting element and in the corresponding areas of the groove and the tongues of the panels, which locking mechanisms lock connected panels in the transverse direction without it being necessary to add glue to the grooves or tongues. In this manner, a particularly easy and quick laying of the floor panels and the connecting elements can be achieved.  
      A clamp, preferably of metal, can be extruded into the connecting element to increase the spring force, which clamp can be curved such that it essentially corresponds to the circumferential contour of the groove. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Exemplary embodiments of the invention are explained below in more detail with the aid of a drawing. They show:  
       FIG. 1  shows two flooring panels connected to one another via a connecting element at the joint in partial view;  
       FIG. 2  shows a sectional enlargement from  FIG. 1  with a projecting lip; and  
       FIG. 3  shows two flooring panels connected to one another via another connection element at the joint in partial view. 
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION  
      The flooring panels  1 ,  2  comprise a medium-density or highly compacted fiber board, e.g., MDF or HDF. On their top side  8  they are provided with a decorative layer  11  that can be formed, e.g., by a paper layer imitating a wood grain or a natural stone surface or a corresponding direct printing that is covered with a synthetic resin layer serving as wear protection. Each panel  1 ,  2  is provided with a tongue  3  and a groove  4  on the side edges I, II, lying opposite one another. The tongue  3  corresponds to the groove  4  in the opposite side. In the area of the groove  4 , the panel  2  is provided with a locking mechanism  6  that interacts with a locking mechanism  5  provided on the underside of the tongue  3  of the panel  1 , and the connected panels  1 ,  2  can engage with one another so that the connected panels  1 ,  2  are locked crosswise to the connection direction.  
      If a visible joint, e.g., a face joint, is to be produced on the top side  8  of the flooring panels between two panels  1 ,  2 , the connecting element  7  is provided, that is embodied in a strip-like manner and has a groove  4   a  or a tongue  3   a  on the side edges Ia, IIa. The tongue  3   a  is provided on its underside with a locking mechanism  5   a.  The groove  4   a  has a locking mechanism  6   a  in the lower area. The embodiment of the tongue  3   a  with its locking mechanism  5   a  and the embodiment of the groove  4   a  with its locking mechanism  6   a  of the connecting element  7  corresponds to the embodiment of the tongue  3  with its locking mechanism  5  or the groove  4  with its locking mechanism  6  of the panels  1 ,  2 . The connecting element  7  thus adapts seamlessly to the connection of two panels  1 ,  2 .  
      One lip  9  each is embodied on the top side  10  of the connecting element  7  in the area of the side edges Ia, IIa, which lips bear on the top side  8  of the panels  1 ,  2  and overlap the butt joint between the panels  1 ,  2  and the connecting element  7 , in order to thus prevent the penetration of moisture into the butt joint between flooring panel  2  and connecting element  7 . On the underside  9   a,  the lips  9  have a flocking with flock fibers that are arranged vertically on the underside  9   a  of the overlapping lips  9  and form a dense arrangement of fibers per unit area and thus provide an improved protection against the penetration of moisture from above into the wooden material core of the flooring panel  1  or  2 .  
       FIG. 3  shows another exemplary embodiment of a connecting element  7  that is provided with an integrated metal clamp  12 . This metal clamp  12  is embedded in the plastic during extrusion and is used to increase the spring force of the connecting element  7 . The clamp  12  is curved such that it essentially corresponds to the enlarged circumferential contour of the groove  4   a  or the tongue  3 .