Abstract:
The invention concerns a panel of a flooring system, in particular a laminate floor, with a first side edge, and with a second side edge which is arranged opposite the first edge, wherein the side edges can be locked with corresponding side edges of further panels, wherein the side edges can be brought into engagement with each other, wherein the first side edge is fitted with at least one locking lip, and with an elasticity groove adjacent to the locking lip, wherein the second side edge is fitted with a locking element and wherein the locking element in the locked state is in engagement with the locking lip. To be able to set the elasticity of the locking lip more satisfactorily, it is provided that the elasticity groove is at least partly filled with at least one filling compound.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention concerns a panel of a flooring system, in particular a laminate floor, with a first side edge and with a second side edge which is arranged opposite the first side edge, wherein the side edges can be locked with corresponding side edges of further panels, wherein the side edges can be brought into engagement with each other, wherein the first side edge is fitted with at least one locking lip and with an elasticity groove adjacent to the locking lip, wherein the second side edge is fitted with a locking element and in the locked state the locking element is in engagement with the locking lip. 
     2. Description of Related Art 
     Panels of this type are known for example from DE 102 31 921 A1. These panels have a carrier board of a wooden material such as a medium density fibre board (MDF) or high density fibre board (HDF). Also a laminate coating can be provided on this carrier board. The disadvantage of these panels is that the elasticity of the locking lip can only be set inadequately by the geometry of the elasticity groove. 
     SUMMARY OF THE INVENTION 
     The present invention therefore is based on the technical problem of specifying a panel in which the elasticity of the locking lip can be set more satisfactorily. 
     This object is achieved according to the invention by a panel of the type cited initially in that the elasticity groove is at least partly filled with at least one filling compound. 
     The elasticity of the locking lip can thus be set by suitable introduction of a filling compound. The locking lip is preferably made from a wooden material like the carrier board of the panel. The carrier board can be a medium density fibre board (MDF) or a high density fibre board (HDF). The material for the carrier board can also be a mixture of a wooden material and a plastic, known as a wood-plastic composite. The carrier board of the panel can have a coating on the top and/or underside such as in the form of a lacquer coating and/or a laminate coating. Corresponding coatings are known from the prior art so these are not described in more detail below. 
     The elasticity groove can have an opening perpendicular and/or parallel to the panel so that the locking lip can be bent suitably. In other words the elasticity groove can run substantially horizontally or substantially vertically as required, in particular depending on whether the locking lip runs substantially horizontally or vertically. The terms horizontal and vertical in this context should be understood as merely preferential directions, so that both the extent of the elasticity groove and the extent of the locking lip can be aligned clearly obliquely to the horizontal and/or the vertical and thus be provided more horizontally or more vertically. 
     A particularly simple locking can be achieved if the side edges can be brought into engagement substantially by a vertical movement, such that the first side edge is provided with a locking lip preferably directed downward from the top and with an elasticity groove arranged on the side of the locking lip facing away from the outer end of the first side edge, that the locking element of the second side edge is formed as a locking tongue and that in the locked state the locking tongue is engaged with the locking lip. 
     If two locking lips are provided, higher extraction forces can be tolerated. For common adjustment of the elasticity of the locking lips, the elasticity groove is suitably adjacent to both locking lips. 
     To simplify and/or strengthen the locking of two corresponding side edges, the locking element of the second side edge can be formed as a locking lip and an elasticity groove adjacent to the locking lip of the second side edge and at least partly filled with at least one filling compound can be provided on the second side edge. 
     A simple and secure locking of the panels in the horizontal and vertical direction is guaranteed in a preferred embodiment in that the first side edge is fitted with a fitting tongue preferably directed downward from the top and with a locking groove arranged between the fitting tongue and the locking lip, that the second side edge is fitted with a fitting groove adjacent to the locking tongue and that in the locked state the fitting tongue is in engagement with the fitting groove, wherein the distal end of the fitting tongue lies on the groove base of the fitting groove and wherein the locking tongue is in engagement with the locking groove and the locking lip. 
     To provide a suitable elasticity, the filling compound is an elastic compound, in particular a silicone, acrylate and/or melt adhesive. 
     Preferably the filing compound is an at least partly foaming filling compound in order to be able to adjust the elasticity of the locking lip suitably. A foaming filling compound is a compound which has a multiplicity of small gas-filled cavities or pores, wherein the cavities in turn can form an open and/or a closed porosity. Thus adaptation of the elasticity of the filling compound and hence the locking lip can easily take place by the selection of the degree of foaming i.e. the proportion of the gas-filled cavity or pore volume in relation to the total volume of the filling compound. In this context foaming degrees in the range of 10 to 35%, in particular 15 to 20%, have proved particularly suitable. 
     By the use of a foamed filling compound, alternatively or additionally a material saving can be achieved and hence a cost saving. Foamed filling compounds have the additional benefit that the elasticity groove is filled to its flanks and if required a full surface connection can be achieved between the filling compound and the flanks of the elasticity groove, in particular the flank adjacent to the locking lip. 
     Optionally the filling compound can be introduced into the elasticity groove at least in a substantially foamed state or at least in a substantially unfoamed state. In the latter case the filling compound substantially foams within the elasticity groove, wherein this is filled to the desired extent. In principle the filling compound can be foamed chemically and/or physically, such as by blowing in a gaseous medium. The gas enclosed in the filling compound, in particular for physical foaming, is air. 
     Good adhesive properties for joining the filling compound to the flanks of the elasticity groove are achieved with the foamed melt adhesives, also called hot melt adhesives. Corresponding filling compounds can be stored in a molten and foamed state in a tank and from there injected via a heated hose into the elasticity groove, wherein the panel and an application nozzle are moved relative to each other along the elasticity groove. 
     In particular if the panels are moved past the application nozzle in succession at a certain distance from each other i.e. with gaps in between, it is suitable if the output of filling compound is pulsed. The output can thus be adapted to the dimensions, advance speed and spacing of the panels such that no filling compound enters the gaps between the panels. This avoids contaminating plant parts and saves filling compound. 
     A pulsed output of filling compound can alternatively or additionally achieve the fact that the elasticity groove is only partly filled in the longitudinal extent. The introduction of filling compound can in principle take place directly after milling the elasticity groove out of the panel material. 
     To ensure as stable as possible a connection between adjacent panels with low force and without damaging the panels, it is suitable if the filling compound hardens slowly. Slow hardening in this context means hardening which takes place so slowly that on proper use the filling compound is only partly hardened during laying and only hardens fully after laying. During laying of the panel the filling compound and hence the locking lip are still quite flexible, while the filling compound only hardens some hours, days or weeks after laying so that a very stable connection is achieved between the panels. 
     As the filling compound should be prevented from hardening completely during storage, hardening can take place at least partly by drying and/or contact with air oxygen. The loss of moisture and the addition of air oxygen can be prevented or at least controlled suitably for example in the packed state of the panels by a suitable choice of packing material. After unpacking of the panels from the packing, the filling compound can, as required, harden much faster than before. 
     Alternatively or additionally the filling compound can be connected by material connection with the panel, such as via the filling compounds previously mentioned. Thus the filling compound and/or the locking lip are securely fixed even if the locking lip breaks. 
     For a precise setting of the bending behaviour of the locking lip over its length, the elasticity groove can be filled at least partly with at least two different filling compounds with different modulus of elasticity. A filling compound with a higher modulus of elasticity in the region of the groove base of the elasticity groove can reduce the bending of the locking lip so that lower stress peaks occur there. 
     A saving of filling compound and hence material costs can be achieved if the at least one filling compound is provided in segments along the longitudinal extent of the elasticity groove. Different filling compounds can also be provided along the longitudinal extent of the elasticity groove. In both cases the bending behaviour of the locking lip can be adapted in segments to particular requirements. 
     The elasticity groove can be angled in relation to the vertical such that the groove base of the elasticity groove in the horizontal direction is arranged closer to the outer end of the first side edge of the panel than the opening of the elasticity groove which preferably points towards the underside of the panel. As a result a suitable bending behaviour of the locking lip can be achieved and the locking lip stabilised. 
     Further preferably the flank of the locking lip adjacent to the elasticity groove can run substantially obliquely to the vertical as a whole, wherein the flank is spaced further in the horizontal direction from the outer end of the first side edge in the region of the opening of the elasticity groove than in the region of the base of the elasticity groove. Also the elasticity groove can have a main orientation aligned obliquely to the vertical between the opening of the elasticity groove and the base of the elasticity groove, without all flank regions of the elasticity groove also having to run obliquely to the vertical. By all these measures the bending behaviour of the locking lip can be improved or adjusted. 
     A particularly robust locking lip can be achieved if the locking lip has at least one tapered segment in the region of the base of the elasticity groove. This can be achieved in that the width of the locking lip in the region of the base of the elasticity groove has a taper at least in one cross section perpendicular to the side edge. The taper forms a nominal break point or break edge if the taper runs substantially along the entire locking lip, so that if the stress is too high, the locking lip breaks in the region of the base of the elasticity groove. Then the locking lip is fixed over a large surface by the filling compound in the elasticity groove. Firstly the locking lip does not detach from the panel. Secondly the locking lip can continue substantially to fulfil its function. 
     The elasticity groove in the region of the groove base can be expanded or widened in relation to the adjacent region of the elasticity groove in order to provide, in a particularly simple fashion, a nominal break point in the region of the groove base of the elasticity groove and/or to be able to introduce the filling compound into the elasticity groove particularly well without disruptive air inclusions, preferably adjacent to the locking lip. If the groove base is also or alternatively rounded, at corresponding points the stress peaks in the material can be reduced. The rounding can be provided at the groove base in the longitudinal extent of the elasticity groove and/or adjacent to the locking lip in the region of the groove base of the elasticity groove. A widening in the region of the groove base can be produced simply and precisely by a broaching tool or an end milling cutter. 
     The presence of an elasticity groove with at least one filling compound allows the locking lip to be made very thin in order to increase the influence of the elasticity groove and/or filling compound on the mechanical properties of the locking lip and optimise these mechanical properties. The locking lip therefore preferably has a smaller, in particular very much smaller horizontal width than the elasticity groove. 
     A better distinction of the panel sides can be achieved if the filling of the elasticity groove is dyed. The side edges can in this way be colour-coded so that the fitter can determine the correct arrangement of the panels more quickly and easily. 
     In a particularly preferred embodiment of the panel, the modulus of elasticity of the at least one filling compound is adapted to the application. For example the flexibility of the locking lip can be adapted by choice of the at least one filling compound and/or by targeted filling of the elasticity groove in segments. 
     The panels can be laid more easily if the panels have a third side edge and a fourth side edge opposite the third side edge, and the third and fourth side edges can be brought into engagement, preferably locked, with corresponding side edges of further panels substantially by a swivel movement about a parallel to the side edges to be joined. Not all side edges are thus brought into engagement by a substantially vertical movement. Via the swivel movement at the same time a first side edge and a third side edge can be connected, preferably locked, with a second and a third side edge of further panels. 
     In principle it is suitable if the first and second side edges are provided on the short narrow sides of the panel. Alternatively or additionally the panel is formed square. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in more detail below with reference to drawing which shows only embodiment examples. The drawing shows: 
         FIG. 1  two locked panels from the prior art; 
         FIG. 2  the panels in  FIG. 1  in separated state; 
         FIG. 3  a first embodiment example of a panel according to the invention; 
         FIG. 4  a second embodiment example of a panel according to the invention; 
         FIG. 5  a third embodiment example of a panel according to the invention; 
         FIG. 6  a fourth embodiment example of a panel according to the invention; 
         FIG. 7  a fifth embodiment example of a panel according to the invention; 
         FIG. 8  a sixth embodiment example of a panel according to the invention; 
         FIG. 9  a seventh embodiment example of a panel according to the invention; 
         FIG. 10  an eighth embodiment example of a panel according to the invention. 
         FIGS. 1 and 2  show two panels  1  and  2  from the prior art. The panels  1  and  2  have a first side edge  3  and a second side edge  4 , wherein the side edges  3  and  4  lie opposite each other on the same panel  1  or  2 . The side edges  3  and  4  can be locked with corresponding side edges  4  and  3  of further panels  1  and  2  as the profiles of the side edges  3  and  4  are formed corresponding to each other. Thus the side edges  3  and  4  can be brought into engagement with each other substantially by a vertical movement. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The first side edge  3  has a fitting tongue  6  directed down away from the top side  5 , a locking lip  7  directed down from the top side  5 , a locking groove  8  arranged between the fitting tongue  6  and the locking lip  7 , and an elasticity groove  9  arranged on the side of the locking lip  7  facing away from the locking groove  8 . The second side edge  4  however is fitted with a locking tongue  11  directed up from the underside  10  and with a fitting groove  12  adjacent to the locking tongue  11 . In locked state the fitting tongue  6  is in engagement with the fitting groove  12 , wherein the distal end  13  of the fitting tongue  6  lies on the groove base  14  of the fitting groove  12 . Furthermore the locking tongue  11  is in engagement with the locking groove  8  and the locking lip  7 . 
     To achieve the horizontal and vertical locking, the profile elements previously explained have the following fitting and locking surfaces. The fitting tongue  6  has a first fitting surface  15  adjacent to the top  5 , a second fitting surface  16  arranged on the inside and a lower third fitting surface  13 , namely the distal end of the fitting tongue  6  previously mentioned. The locking lip  7  is fitted with a first locking surface  17  running obliquely to the top  5 . Furthermore on the second side edge  4  is provided a fourth fitting surface  18  adjacent to the top  5 . The locking tongue  11  in turn has a second locking surface  19  running obliquely to the underside  10  and a fifth fitting surface  20 . The groove base  14  of the fitting groove  12  forms the sixth fitting surface. 
     In the locked state the first fitting surface  15  lies on the fourth fitting surface  18 , the second fitting surface  16  on the fifth fitting surface  20 , the third fitting surface  13  on the sixth fitting surface  14  and the first locking surface  17  on the second locking surface  19 . In other words the fitting surface pair  15  and  18  and the fitting surface pair  16  and  20  form the horizontal lock as these fitting surfaces run substantially vertically. Fitting surface pair  13  and  14  and locking surface pair  17  and  19  however form the vertical lock. As the locking surfaces  17  and  19  run obliquely, these have an effect both in relation to the horizontal and the vertical locking. 
     The locking groove  8  at the side opposite the fitting tongue  6  can have a first contact surface  21  while the locking tongue  7  on the side facing away from the fitting groove  12  can have a second contact surface  22  so that in the locked state the two side edges  3  and  4  lie against the first contact surface  21  and second contact surface  22 . This is not itself necessary for locking of the profiles but leads to a stabilisation of the entire profile. 
       FIGS. 3   a  to  3   c  show a derivation of the panel  1  shown in  FIGS. 1 and 2 . The common features of the panel arise as described above. The derivation lies substantially in that the elasticity groove  9  is filled with a filling compound  30 . Therefore in  FIGS. 1 to 3  the same reference numerals are used for the same elements. 
     The filling compound  30  is preferably an elastic compound, in particular a silicone, acrylate and/or melt adhesive. The elasticity groove  9  can if necessary also be filled only partly with the filling compound or different filling compounds. Optionally the elasticity groove can also be unfilled. The elasticity groove  9  of the panel  1  shown is angled in relation to the vertical such that the groove base  32  of the elasticity groove  9  is arranged in the horizontal direction closer to the outer end  34  of the first side edge  3  of the panel  1  than the opening  36  of the elasticity groove  9 . The opening  36  in the embodiment example shown is aligned parallel to panel  1 . The outer end is the end of the panel in a direction perpendicular to the first edge and parallel to the panel. 
     The elasticity groove  9  in the region  37  of the groove base  32  is furthermore widened in relation to the adjacent region  38  of the elasticity groove  9  so as to form a nominal break point  40  in the form of a tapered segment  23  of the locking lip  7 . On mechanical failure, a crack  42  is formed at the nominal break point  40 . The locking lip  7  is held at the flank  44  adjacent to the elasticity groove by the filling compound  30  over a large area as the filling compound  30  is connected by material fit with the panel  1  and in particular the locking lip  7 . 
     In the panel  1  shown in  FIG. 3 , the locking lip  7  provided on the first side edge  3  runs substantially from top to bottom, wherein the elasticity groove  9  extends in the same direction on the side of the locking lip  7  facing away from the outer end  34  of panel  1 . The locking tongue  11  provided on the second side edge  4  runs corresponding to said groove and in the connected state of the panel  1 ,  2  is in engagement with the locking lip  7  while the downwardly directed fitting tongue  6  is in engagement with the fitting groove  12  and the distal end  13  of the fitting tongue  6  lies on the groove base  14  of the fitting groove  12 . The locking tongue  11  in the joined state of the panels  1 ,  2  is in engagement both with the locking lip  7  and with the locking groove  8 , the locking groove  8  being arranged between the fitting tongue  6  and the locking lip  7 . 
       FIG. 4  shows two similar panels  50 ,  52  with a first side edge  54  which for connection are arranged substantially in a direction parallel to panels  50 ,  52  and vertical to the first side edge  54 . The first side edge  54  has a catch element  55  with two substantially horizontal locking lips  56 ,  58 . Between and adjacent to the locking lips  56 ,  58  is an elasticity groove  62  filled with a filling compound  60 . The elasticity groove  62  extends substantially parallel to the panel  50  and has an opening  63  which is oriented vertically to the panel  50 . The second side edge  64  has a recess  66  corresponding to the catch element  55 . On connection of the catch element  55  and recess  66  in the direction of the arrow  68 , the filling compound  60  is compressed and the locking lips  56 ,  58  are bent in the direction of the elasticity groove  62 . 
       FIG. 5  shows two further panels  70 ,  72  which are provided for connection by a substantially vertical movement. The first side edge  74  of panels  70 ,  72  has an outer end  75  and two downwardly pointing locking lips  76 ,  78  adjacent to an elasticity groove  82  that is filled with a filling compound  80  and open to the bottom. In the regions facing away from the free ends of the locking lips  76 ,  78 , tapered segments  77 ,  79  are also provided which on increased load can serve as nominal break points for the locking lips  76 ,  78 . The locking element  84  of the second side edge  86  of the similar panels  70 ,  72  has two locking lips  88 ,  90  with correspondingly tapered segments  89 ,  91 , wherein each of the locking lips  88 ,  90  is adjacent to an elasticity groove  92 . The elasticity grooves  92  in a region adjacent to the groove base and in a region adjacent to the opening of the elasticity groove  92  have filling compounds  94 ,  96  with different moduli of elasticity. 
       FIG. 6  shows panels  100 ,  102  with a first side edge  104  which has a tongue  106  while the second side edge  108  of the panels  100 ,  102  has a corresponding recess  110 . The tongue  106  can be locked with recess  110  via a swivel movement. The second side edge  108  on a lower segment largely parallel to panel  102  and protruding outward thus has a protruding locking lip  112  and an elasticity groove  116  filled with filling compound  114  and extending substantially in a horizontal direction. The elasticity groove  116  expands in the direction of the protruding end of the elasticity groove  116  which there ends in an opening  117  perpendicular to panel  72 . 
       FIG. 7  shows two panels  120 ,  122  which resemble the panels  100 ,  102  in  FIG. 6 . The lower protruding lip  122  of the second side edge  123  is largely formed as an elastic element  124  of an elastic filling compound. At the end of the elastic element  124  is a locking means  126  made of a wooden material and connected with the remaining panel only via the elastic element  124 . 
       FIG. 8  shows two further panels  130 ,  132  with corresponding first side edges  134  with a catch element  136  and second side edges  137  with a recess  140 . The catch element has a thickening  138 . In the extension of the recess  140  is provided an elasticity groove  144  filled with a filling compound  142  and also extending in the horizontal direction. When the panels  130 ,  132  are joined in the direction of arrow  146 , the locking lips  148 ,  150  adjacent to the elasticity groove  144  on both sides are spread apart. Because of the filling compound  142  in the elasticity groove  144 , the panel  132  does not crack in the region of recess  140 , in particular in the region of the groove base of recess  140 . 
       FIG. 9  shows panels  160 ,  162  in which the first side edge  164  has a tongue  166  and the second side edge  168  has a corresponding groove  170 . The side edges  164 ,  168  can be brought into engagement with each other substantially by a swivel movement of the first panel  160  about a parallel to the side edges  164 ,  168  to be connected. The tongue  166  furthermore has a locking lip  172  extending downwards with an elasticity groove  174  adjacent thereto. The elasticity groove  174  is adjacent to the side of the locking lip  172  facing the outer end of the panel  160 . Furthermore a tapered segment  175  is provided on the locking lip  172  in the region facing away from the free end. Here usually the locking lip  172  will break first under increased load. The elasticity groove  174  is filled with two filling compounds  176 ,  178  of different moduli of elasticity. The locking element  180  is formed as a lower lip  182  protruding outwards parallel to panel  162  with a protrusion  184  at the distal end. The lower lip  182  on the underside  186  has a recess  188  with is filled with a filling compound  190  that positively influences the bending of the lower lip  182  on joining of panels  160 ,  162 . 
     The panel  200  shown in  FIG. 10  has a locking lip  206  on a first side edge  202  on the underside  204 . The locking lip  206  is adjacent to an elasticity groove  208  which is filled with a filling compound  210  in segments with interruptions  212 . Such a segmented filling of an elasticity groove is in principle also possible with the other embodiment examples. The second side edge of the panel  200  corresponding to the first side edge  202  can if necessary be formed corresponding to the second side edge  4  shown in  FIG. 3   a.