Abstract:
A floor panel with coupling devices is provided. The coupling devices have locking elements which include a curved protrusion which is formed on a lower wall of an upper lip of a groove and adjacent to the entrance of the groove, and a curved recess which is formed in an upper side of a tongue and can match with the curved protrusion. Under the cooperation of the elastic deformation of the upper lip of the groove and the engagement of the locking elements, adjacent floor panels can be coupled together by exerting on them a horizontal pressing force and interlocked tightly by meshing engagement of the curved protrusion at the groove and the curved recess in the tongue without glue or other auxiliary binding material so as to ensure that the adjacent floor panels can not move in both horizontal direction and vertical direction. The floor panels are usually used in a floor decoration of indoor environment and have the advantages of easy installation and tight coupling.

Description:
CROSS REFERENCES 
     The present application claims priority from Chinese Patent Application No. 200810198567.9 filed Sep. 10, 2008. 
     FIELD OF APPLICATION 
     The present application relates to a floor panel which has coupling devices to couple a plurality of separated smaller floor panels into a larger area of floor covering. Such floor panel is usually made of solid wood or synthetic fiber board and has generally the shape of a rectangle. The coupling devices usually are provided respectively in at least a longer side and a shorter side of the smaller floor panel, are used to detachably couple adjacent floor panels to form a larger area of floor covering when a floor decoration of indoor environment such as living-room or office is under way. 
     BACKGROUND 
     As a kind of indoor flooring material, wooden floor is widely used. Such wooden floor is generally assembled by coupling a plurality of smaller size floor panels together. It is known that such floor panels can be coupled in various ways. According to a first possibility, the floor panels are attached on the underlying floor or support frame, either by gluing or by nailing them on. This technique has a disadvantage in that it is rather complicated and that subsequent changes can only be made by breaking out the floor panels. According to a second possibility, the floor panels are installed loosely onto the sub-flooring, whereby the floor panels mutually match into each other by means of a tongue and groove coupling. For example, CN02803650.6 discloses a rectangular floor panel having coupling devices in form of tongues and grooves. Such floor panel comprises an undercut groove on one long side and a projecting tongue on an opposite long side of the floor panel. The undercut groove has a corresponding upward inner locking surface at a distance from its tip. Tongue and undercut groove are formed to be brought together and pulled apart by pivoting motion with a center close to the intersection between the surface planes and the common joint plane of two adjoining floor panels. Such floor panel has an advantage in that it is much cheaper and convenience to install and repair. But a disadvantage of such floor panel is that an unreasonable design of the tongue and groove possibly results in that the floor panels cannot be coupled tightly when gaps between the floor panels or bumps on the coupling surfaces occur. These defects not only affect the appearance and use of the floor covering but shorten the lifespan of the floor covering. 
     SUMMARY 
     It is aimed to provide an improved floor panel having coupling device with which a plurality of separated smaller floor panels can be coupled into a larger area of floor covering. Such floor panels can be coupled to each other in an optimum manner and adapt to an uneven floor surface, and whereby preferably one or more of the aforementioned disadvantages are excluded. 
     According to a first aspect, there is provided a floor panel with coupling device. The floor panel includes an upper side which is used for treading, an underside which contacts the underlying floor and a first end wall and a second end wall which are parallelly located at a distance from each other and extend in the direction perpendicular to the upper side. A groove is provided in the first end wall and adjacent the underside. The groove extends perpendicularly into the first end wall along the intersection between the upper side and the first end wall. A third end wall is formed between the groove and the underside and perpendicular to the upper side. A tongue is provided in the second end wall and adjacent the underside. The tongue extends perpendicularly outward from the second end wall along the intersection between the upper side and the second end wall. A fourth end wall is formed between the tongue and the underside and perpendicular to the upper side. The first end wall, the third end wall and the fourth end wall are parallel to each other. The groove orderly includes a first slot wall, a second slot wall, a third slot wall, a fourth slot wall, a fifth slot wall and a sixth slot wall. The first slot wall connects the first end wall and is formed by a protrusion with a curved shape which protrudes downward towards the entrance of the groove. The second slot wall, the fourth slot wall and the sixth slot wall are parallel to the upper side. The third slot wall is parallel to the first end wall and extends in the direction that the entrance of the groove dwindles to the inner bottom of the groove. The fifth slot wall is parallel to the first end wall. The tongue orderly includes a first side, a second side, a third side, a fourth side, a fifth side and a sixth side. The first side connects the second end wall and is formed by a recess with a curved shape. The second side, the fourth side and the sixth side are parallel to the upper side. The third side is parallel to the second end wall and extends in the direction that the bottom portion of the tongue dwindles to the distal tip of the tongue. The first slot wall has the same diameter and arc length as the first side of the tongue so that they can be meshingly engaged when adjacent identical ones of the floor panel are coupled together. The total length of the second slot wall and the fourth slot wall is longer than that of the second side and the fourth side of the tongue. 
     Preferably, the joint portion of the first slot wall and the second slot wall aligns to the plane of the third end wall in the direction perpendicular to the first end wall. The joint portion of the first side and the second side aligns to the plane of the fourth end wall in the direction perpendicular to the second end wall. 
     Preferably, a seventh slot wall is provided between the sixth slot wall and the third end wall of the floor panel which widens the entrance of the groove. A seventh side is provided between the sixth side and the fourth end wall so as to reinforce the bottom portion of the tongue. The seventh slot wall inclines at the same angle as the seventh side. 
     Preferably, the edges between the second and third sides, the fourth and fifth sides, and the fifth and sixth sides are rounded. 
     Preferably, the edges between the second and third sides, the fourth and fifth sides, and the fifth and sixth sides are chamfered respectively to form corresponding skew walls which maintain certain angles with their adjacent sides. 
     Preferably, the length of the fourth slot wall is longer than that of the fourth side. 
     Preferably, when the floor panel is coupled and interlocked with another identical floor panel, a gap is formed between the third end wall of the floor panel and the fourth end wall of another identical floor panel in the direction perpendicular to the first end wall of the floor panel. 
     The coupling devices of the floor panels are configured to enable the floor panels to be interlocked together by locking elements which include a curved protrusion which is formed on the lower wall of the upper lip of the groove and adjacent to the entrance of the groove and a curved recess which is formed in the upper side of the tongue and can match with the curved protrusion. Under the cooperation of the elastic deformation of the upper lip of the groove and the engagement of the locking elements, the adjacent floor panels can be coupled together by exerting them a horizontal pressing force and interlocked tightly by meshing engagement of the curved protrusion and the curved recess without glue or other auxiliary binding material so as to ensure that the adjacent floor panels can not move in both horizontal direction and vertical direction. The configuration of the coupling device is in such a way that the entrance of the groove is larger than its inner bottom and the tongue has the corresponding structures that the distal tip of it is smaller than its bottom portion making it easy to guide the tongue into the groove of the floor panel, which improves the location of adjacent floor panels in the direction perpendicular to the upper side of the floor panel. Meantime, the assembly of the panels with such configuration can be achieved just by exerting on the floor panels a horizontal pressing force, which permits an operator to complete the flooring at a restricted room and speeds up the coupling work. Additionally, such configuration that the lower lip of the groove is shorter than its upper lip making the lower lip more stress-tolerant and the floor covering more resistant to an uneven sub-floor surface, which promotes the floor panel&#39;s adaptability to different sub-floor surfaces. Based on the above configurations, the gaps can be formed between the groove and the tongue by regulating the length of related elements of the coupling devices. The gaps provide an operator supporting points which make it easier to couple and detach the floor panels and thus prevent the floor panels from being deadlocked. 
     The floor panel will be further explained in connection with the following figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a floor panel before the coupling devices are formed thereon; 
         FIG. 2  is a perspective view of the floor panel formed with the coupling devices according to an embodiment disclosed in the present application; 
         FIG. 3  is a cross sectional view of the floor panel with the coupling devices; 
         FIG. 4  is an enlarged cross sectional view of a groove of the coupling device of the floor panel; 
         FIG. 5  is an enlarged cross sectional view of a tongue of the coupling device of the floor panel; 
         FIG. 6  shows the first stage when the floor panel with coupling devices of  FIG. 2  is coupled to another identical floor panel; 
         FIG. 7  shows the second stage when the floor panel with coupling devices of  FIG. 2  is coupled to another identical floor panel; and 
         FIG. 8  shows an interlocking stage when two identical floor panels with coupling devices of  FIG. 2  are coupled together. 
     
    
    
     DETAILED DESCRIPTION 
     Different aspects of the floor panel with coupling devices will now be described in more detail with reference to the accompanying figures. The elements, characteristics or structures of the floor panel that are equivalent to those of the floor panels in all figures have been given the same reference numbers. The floor panel with coupling devices is in no way limited to the forms of embodiment described by way of example and represented in the figures if the floor panel d can be embodied in various forms and dimensions without departing from the scope of the appended claims. For example, the various characteristics which are described by means of the represented embodiments or examples may be selectively combined with each other. Any technical solutions that are equivalent or similar to those of the floor panel with coupling devices in the present application fall into the scope of the appended claims. In addition, the describing of public-known functions and structures in the description are simplified or ignored for conciseness. 
       FIGS. 1 ,  2 ,  3 ,  4  and  5  represent a floor panel d. As shown in  FIG. 1 , the floor panel d may be in the form of a substantial rectangular solid where the coupling devices of the floor panel are not formed yet.  FIG. 2  shows the floor panel d where the coupling devices have been formed.  FIGS. 3 ,  4  and  5  represent the cross section of the floor panel with coupling devices in direction z. For better describing the examples, the coordinate system shown in  FIGS. 1 ,  2 ,  3 ,  4  and  5  is chosen as the reference directions of the floor panel d. The reference directions are corresponding to the actual directions of the floor panel d under installing posture as follows: the direction x in the figures is corresponding to the direction perpendicular to the upper side  101  of the floor panel d, and the direction y in the figures is corresponding to the direction that is simultaneously parallel to the upper side  101 and the short side  102  of the floor panel d, and the direction z in the figures is corresponding to the direction that is simultaneously parallel to the upper side  101  and the long side  103  of the floor panel d. The upper side of the panel d is parallel to the horizontal plane when the floor panel d is installed. 
     Generally, the floor panel d may be made of solid wood, synthetic fiber board, or any other suitable material. As shown in  FIG. 1 , the floor panel d may be in the form of a flat rectangular solid before its coupling devices are formed. The floor panel d may include an upper side  101 , an underside  107  and four lateral walls. The upper side  101  is usually provided with a decorative layer and used to contact and support a man walking on it or other articles; and the underside  107  is provided to contact the underlying floor or supporting frame. The upper side  101  and underside  107  are parallel to each other. The lateral walls  104  and  105  are corresponding to the longer edge  103  and another two lateral wall are corresponding to the shorter edge  102 . All the four lateral walls can be perpendicular to the upper side  101 , i.e. the four lateral walls are parallel to the direction x. The lateral walls  104  and  105  corresponding to the longer edge  103  are parallel to the direction z and perpendicular to another two lateral walls that are corresponding to the shorter edge  102 . And the two lateral walls corresponding to the shorter edge  102  are parallel to the direction y. 
     As represented in the  FIGS. 2 to 5 , the lateral walls  104  and  105  corresponding to the longer edge  103  of the floor panel d can be configured respectively as described below (the lateral walls corresponding to the shorter edge  102  can also have the similar configurations). 
     The portion of the lateral wall  104  adjacent to the upper side  101  can be provided as the first end wall  106 . The portion of the lateral wall  104  adjacent to the underside  107  is cut away to form the third end wall  108  which is parallel to the first end wall  106 . A groove  109  is provided between the first end wall  106  and the third end wall  108  and extends to the two lateral walls corresponding to the shorter edge  102  in the direction z. In other words, the groove  109  may have the same length as the lateral wall  104  and recesses the floor panel d in the direction y. 
     The groove  109  may include a first slot wall  110 , a second slot wall  111 , a third slot wall  112 , a fourth slot wall  113 , a fifth slot wall  114 , a sixth slot wall  115  and a seventh slot wall  116 . In the direction y that is also the direction that the tongue of the floor panel d is inserted into the groove  109 , the upstream end of the first slot wall  110  connects to the lower side of the first end wall  106 ; the downstream end of the first slot wall  110  connects to the upstream end of the second slot wall  111 ; the downstream end of the second slot wall  111  connects to the upper side of the third slot wall  112 ; the lower side of the third slot wall  112  connects to the upstream end of the fourth slot wall  113 ; the downstream end of the fourth slot wall  113  connects to the upper side of the fifth slot wall  114 ; the lower side of the fifth slot wall  114  connects to the downstream end of the sixth slot wall  115 ; the upstream end of the sixth slot wall  115  connects to the downstream end of the seventh slot wall  116 ; the upstream end of the seventh slot wall  116  connects to the upper side of the third end wall  108 ; and the lower side of the third end wall  108  connects to the underside  107 . 
     The first slot wall  110  may be formed by a protrusion with a curved shape which protrudes downward towards the entrance of the groove  109 . The second slot wall  111 , the fourth slot wall  113  and the sixth slot wall  115  are parallel to the upper side  101 . The third slot wall  112  may be located substantially in the middle portion of the groove in the direction y is parallel to the first end wall  106  and extends in the direction that the entrance of the groove  109  dwindles to the inner bottom of the groove  109  which is corresponding to the fifth slot wall  114 . The fifth slot wall  114  is also parallel to the first end wall  106 . The seventh slot wall  116  can be configured in the form of a skew wall which inclines from the sixth slot wall  115  to the third end wall  108  or the underside  107  so that the entrance of the groove  109  is widened so as to easily guide the tongue  119 . The joint portion of the downstream of the first slot wall  110  and the upstream of the second slot wall  111  aligns to the third end wall  108  in the direction y. In other words, the first slot wall  110  is in the upstream side of the third end wall  108  in the direction y. Thus, the first end wall  106  is farther away from the inner bottom of the groove  109  than the third end wall  108  in the direction y. 
     The portion of the lateral wall  105  adjacent to the upper side  101  can be provided as a second end wall  117 . A fourth end wall  118  may be formed on an extra part that is filled up on the portion of the lateral wall  105  adjacent to the underside  107 . The extra part may be made of the same material as the floor panel d. Herein the extra part is described in relation to the lateral wall  105 , and actually, the extra part can also be looked as the original parts of the floor panel d. The fourth end wall  118  is parallel to the second end wall  117 . A tongue  119  can be provided between the second end wall  117  and the fourth end wall  118  and protrudes outward from the lateral wall  105  in the direction of y. The tongue  119  extends in the direction z to the two lateral walls which are corresponding to the shorter edge  102 . In other words, the tongue  119  has the same length as the lateral wall  105  and the groove  109  in the direction z. 
     The tongue  119  may include a first side  120 , a second side  121 , a third side  122 , a fourth side  123 , a fifth side  124 , a sixth side  125  and a seventh side  126 . In the direction of y which is also the direction that the tongue  119  is inserted into the groove  109 , the upstream end of the first side  120  connects to the lower side of the end wall  117 ; the downstream end of the first side  120  connects to the upstream end of the second side  121 ; the downstream end of the second side  121  connects to the upper side of the third side  122  by a skew wall  127 ; the lower side of the third side  122  connects to the upstream end of the fourth side  123 ; the downstream end of the fourth side  123  connects to the upper side of the fifth side  124  by a skew wall  128 ; the lower side of the fifth side  124  connects to the downstream end of the sixth side  125  by a skew wall  129 , the upstream end of the sixth side  125  connects to the downstream end of the seventh side  126 ; and the upstream end the seventh side  126  connects to the upper side of the fourth end wall  118 . 
     The skew walls  127 ,  128  and  129  can be configured to maintain certain angles with their adjacent sides. Alternatively, the skew walls  127 ,  128  and  129  can be configured in a round chamfering form. The first side  120  may be formed by a downward recess with a curved shape. The second side  121 , the fourth side  123  and the sixth side  125  are parallel to the upper side  107 . The third side  122  may be located substantially in the middle portion of the tongue  119  in the direction y is parallel to the second end wall  117  and extends in the direction that the bottom portion of the tongue  119  dwindles to the distal tip of the tongue  119  which is corresponding to the fifth side  124 . The fifth side  124  is parallel to the second end wall  117 . The seventh side  126  may be configured in the form of a skew wall which inclines from the sixth side  125  to the fourth end wall  118  or the underside  107  so as to reinforce the bottom portion of the tongue  119 . The joint portion of the downstream of the first side  120  and the upstream of the second side  121  aligns to the fourth end wall  118  in the direction y. In other words, the fourth end wall  118  is in the downstream side of the second end wall  117  in the direction y. 
     The first slot wall  110  of the groove  109  may have the same arc length and diameter of the curved surface as the first side  120  of the tongue  119 . The seventh slot wall  116  is parallel to the seventh side  126 , i.e. the angle between the seventh slot wall  116  and the sixth slot wall  115  is equal to the one between the seventh side  126  and the sixth side  125 . The total length of the second slot wall  111  and the fourth slot wall  113  may be longer than that of the second side  121  and the fourth side  123  so that a gap  130  can be formed between the fifth slot wall  114  of one floor panel and the fifth side  124  of another identical floor panel in the direction y when the two same floor panels are coupled together, as shown in  FIG. 8 . Of course, the gap  130  between the fifth slot wall  114  and the fifth side  124  of two floor panels can also be formed by the fourth slot wall  113  configured longer than the fourth side  123  in the same floor panel. 
     The  FIGS. 6 ,  7  and  8  show three different stages of the coupling of two floor panels with coupling devices. 
     As represented in  FIG. 6 , before coupling two identical floor panels d and d′, an operator firstly aligns the tongue  119  of the floor panel d with the groove  109  of the floor panel d′ and exerts a horizontal force to move the floor panel d towards the floor panel d′ in the direction y. 
     As shown in  FIG. 7 , when the floor panel d is coupled to the floor panel d′, the second side  121  of the floor panel d contacts the first slot wall  110  of the floor panel d′ first. Then, with the tongue  119  of the floor panel d moving on, the sixth side  125  of the floor panel d is guided by the skew wall  129  into the groove  109  of the floor panel d′ and contacts the sixth slot wall  115  of the floor panel d′. At the same time, the second side  121  of the floor panel d forces the upper lip where the first slot wall  110  of the floor panel d′ is located deformed elastically in the direction of x so that the tongue  119  of the floor panel d can be inserted further towards the inner bottom of groove  109  of the floor panel d′. 
     As shown in  FIG. 8 , when the two floor panels d and d′ are coupled together completely, the deformed upper lip where the first slot wall  110  is located returns to its normal appearance and the first slot wall  110  of the floor panel d′ engages with the first side  120  of the floor panel d, which ensures that the two floor panels coupled to each other can not move laterally in the direction y with respect to each other. Meanwhile, the second end wall  117  of the floor panel d comes in contact with the first end wall  106  of the floor panel d′. In this engaged condition of the two floor panels, the difference of the length between the fourth slot wall  113  and the fourth side  123  of a floor panel, as shown in  FIGS. 4 and 5 , results in that the gap  130  is formed in the direction y between the fifth side  124  of the floor panel d and the fifth slot wall  114  of the floor panel d′ when the two identical floor panels d and d′ are coupled together. Similarly, the gap  131  can be formed in the direction y between the fourth end wall  118  of the floor panel d and the third end wall  108  of the floor panel d′ in the coupled condition of the two floor panels.