Patent Publication Number: US-7721503-B2

Title: Locking system comprising a combination lock for panels

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present application claims the benefit of U.S. application Ser. No. 11/770,771, which was filed on Jun. 29, 2007, and claims the benefit of U.S. Provisional Application Ser. No. 60/830,677, which was filed on Jul. 14, 2006, and the entire contents thereof are incorporated herein by reference. 

   FIELD OF INVENTION 
   The invention generally relates to the field of floor panels with mechanical locking systems with a flexible and displaceable tongue. 
   BACKGROUND 
   In particular, yet not in a restrictive manner, the disclosure concerns a locking system for a floor panel and a set of floor panels mechanically joined to preferably a floating floor. However, the disclosure is as well applicable to building panels in general. More particularly, the disclosure relates to the type of mechanically locking systems comprising a flexible or partly flexible tongue and/or a displaceable tongue, in order to facilitate the installation of building panels. 
   A floor panel of this type is presented in WO2006/043893, which discloses a floor panel with a locking system comprising a locking element cooperating with a locking groove, for horizontal locking, and a flexible tongue cooperating with a tongue groove, for locking in a vertical direction. The flexible tongue bends in the horizontal plane during connection of the floor panels and makes it possible to install the panels by vertical folding or solely by vertical movement. By “vertical folding” is meant a connection of three panels where a first and second panel are in a connected state and where a single angling action connects two perpendicular edges of a new panel, at the same time, to the first and second panel. Such a connection takes place for example when a long side of the first panel in a first row is already connected to a long side of a second panel in a second row. The third panel is then connected by angling to the long side of the first panel in the first row. This specific type of angling action, which also connects the short side of the new panel and second panel, is referred to as “vertical folding”. It is also possible to connect two panels by lowering a whole panel solely by vertical movement against another panel. 
   DEFINITION OF SOME TERMS 
   In the following text, the visible surface of the installed floor panel is called “front face”, while the opposite side of the floor panel, facing the sub floor, is called “rear face”. The edge between the front and rear face is called “joint edge”. By “horizontal plane” is meant a plane, which extends parallel to the outer part of the surface layer. Immediately juxtaposed upper parts of two adjacent joint edges of two joined floor panels together define a “vertical plane” perpendicular to the horizontal plane. 
   By “joint” or “locking system” are meant co-acting connecting means, which connect the floor panels vertically and/or horizontally. By “mechanical locking system” is meant that joining can take place without glue. Mechanical locking systems can in many cases also be combined with gluing. By “integrated with” means formed in one piece with the panel or factory connected to the panel. 
   By a “flexible tongue” is meant a separate tongue which has a length direction along the joint edges and which is forming a part of the vertical locking system and could be displaced horizontally during locking. The tongue could for example be bendable or have a flexible and resilient part in such a way that it can bend along its length and spring back to its initial position. 
   By “angling” is meant a connection that occurs by a turning motion, during which an angular change occurs between two parts that are being connected, or disconnected. When angling relates to connection of two floor panels, the angular motion takes place with the upper parts of joint edges at least partly being in contact with each other, during at least part of the motion. 
   OBJECTS AND SUMMARY 
   The present disclosure discloses a locking system and a set of floor panels or a floating flooring, which provides for new embodiments according to different aspects offering respective advantages. Useful areas for the disclosure are floor panels of any shape and material e.g. laminate, wood, HDF, veneer or stone. 
   According to a first object, the disclosure provides for locking system for a floor panel comprising a first connecting device. The first connecting device comprises a combination lock configured to lock horizontally and vertically to a second and third connecting devices of a second and third connecting device, respectively. The combination lock comprises a locking element for cooperating with a locking grove of the second and third connecting device, for the horizontal locking. Further more, the combination lock comprises a flexible tongue and displacement groove, configured to cooperate with a flexible tongue groove of the second floor panel and a tongue of a third floor panel. 
   As the locking system for a floor panel according to the first object is provided with a flexible and displaceable tongue, displaceable in a displacement groove and configured to cooperate with a flexible tongue groove as well as with a tongue, this offers several advantages. A first advantage is that it is possible to connect one side of a floor panel with a first connecting device to two different connecting devices. A second advantage is that a strong joint is provided and a third that the height position between the floor panels, in the short edge to long edge joint is improved. 
   A locking system for a floor panel of this type is known from WO2006/043893, as mentioned above, and discloses a bow shaped flexible tongue bendable in the length direction. The drawback of this locking system is that if it is used on a joint between a long and short side it weakens the joint. The first panel has a long edge of an angling type (see  FIG. 10   a ), comprising a locking element and a tongue groove. To facilitate the connection to a short side of a second panel, the short side is provided with a flexible tongue and a displacement groove. This results in a very thin section between the bottom of the displacement groove and the locking groove. The thin section makes the joint weak and it&#39;s likely that this thin section will crack when the joint is put under load. 
   Preferably, the length of the displacement groove is at least equal to the sum of the width of the flexible tongue and the tongue. 
   Preferably, the width of the entrance E of the displacement groove is at least equal to the thickness TT of the tongue. 
   Preferably, the flexible tongue is displaceable via the tongue. 
   Preferably, the panels joined are of A and B type, with mirror inverted connecting devices. 
   Preferably, the flexible tongue has a straight outer edge and an inner edge with bendable protrusions. 
   According to a second object, the disclosure provides for a set of floor panels comprising the combination lock above at two of the edges of a first panel, configured to cooperate with the second connecting device of a second panel and with a third connecting device of a third panel. The set of floor panels has the same advantage as mentioned above and it is provides for easy installation of advanced patterns. 
   All references to “a/an/the [element, device, component, means, step, etc]” are to be interpreted openly as referring to at least one instance of said element, device, component, means, step, etc., unless explicitly stated otherwise. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1   a - b  illustrate a locking system according to an embodiment of the invention. 
       FIG. 2  shows an installation of two panels according to an embodiment of the invention, a tongue side of a panel is connecting a tongue side of an adjacent panel. 
       FIG. 3  shows an installation of two panels according to an embodiment of the invention, a tongue side of a panel is connecting a groove side of an adjacent panel. 
       FIGS. 4   a - b  show short sides of two floor panels, according to prior art, with a locking system adapted for vertical folding. 
       FIGS. 5   a - b  show locking of short sides of two floor panels, according to prior art, with a locking system adapted for vertical folding. 
       FIG. 6  shows locking with vertical folding in a 3D-view. 
       FIGS. 7   a - e  show displaceable tongues in embodiments according to the invention. 
       FIGS. 8   a - e  show embodiments of applicable installation patterns. 
       FIGS. 9   a - d  show embodiments of the locking system of the invention applied to rectangular and square A and B panels. 
       FIG. 10   a  shows a prior art locking system. 
       FIGS. 10   b - d  show embodiments of the locking system according to the invention. 
       FIG. 11  shows an installation of panels in a pattern, comprising A, B and square panels for which the locking system of the invention is applicable. 
       FIGS. 12   a - b  shows an embodiment of a combination of locking system, comprising rectangular and quadratic A and B panels for which the locking system of the invention is applicable. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
   As represented in  FIGS. 1-3  and  7 - 12 , the invention relates to a locking system and a set of floor panels with a displaceable tongue. 
     FIGS. 1   a - b  show an embodiment of a locking system according to the invention.  FIG. 1   b , shows the locking system in a state wherein a first connecting device, a combination lock C, of a first panel  1 , is connected to a second connecting device FG of a second panel  1 ′. The combination lock comprises a locking strip  6  and an upwardly projected locking element  8  cooperating with a locking groove  14  of the second connecting device for horizontal locking. Further more, the combination lock comprises a flexible and displaceable tongue  15 , displaceable in a displacement groove  40 , cooperating with a flexible tongue groove  20 , of the second connecting device for locking in the vertical direction. Henceforward, the second connecting device will be referred to as a FG-lock.  FIG. 1   a , shows the locking system in a state wherein the combination lock is connected to a third connecting device T of a third panel  3 . The third connecting device comprising a locking groove  14  cooperating with the locking element of the combination lock for horizontal locking. Further, the third connecting device comprises a tongue, pushing the flexible tongue of the combination lock into the displacement groove, and cooperating with the displacement groove for locking in the vertical direction. Henceforward, the third connecting device will be referred to as a T-lock 
     FIGS. 1   a - b  show an embodiment with a depth D of the displacement groove  40  equal to the width of the flexible tongue F and the tongue S. A deeper displacement groove is possible, and also a shallower is possible if the properties of the tongue allow compression and/or foiling. 
     FIG. 2  shows in four steps a preferred connection method of the first panel with the combination lock C to the third panel with the T-lock. The panels are connected by angling and the flexible tongue is pushed into the displacement groove. The panels are preferable provided with guiding surfaces  22  which facilitate overcoming the displacement resistance of the flexible tongue. The width of the entrance E of the displacement groove is preferably at least equal to the thickness TT of the tongue. The entrance of the displacement groove is in this relationship defined to start at the joint plane. 
     FIG. 3  shows in four steps a preferred connection method of the first panel with the combination lock C to the second panel with the FG-lock. The panels are connected by folding or solely by vertical movement of the whole panel and the flexible tongue is during the connection pushed into the displacement groove and springs then back into the flexible tongue groove. The panels are preferable provided with guiding surfaces  22  which facilitate overcoming the displacement resistance of the flexible tongue. 
   A prior art floor panel  1 ,  1 ′ provided with a mechanical locking system and a displaceable tongue is described with reference to  FIGS. 4 and 5 . The mechanical locking system provides locking of the panels relative to each other in the vertical direction D 1  as well as the horizontal direction D 2 . 
   To provide joining of the two joint edges in the D 1  and D 2  directions, the edges of the floor panel have in a manner known per se a locking strip  6  with a locking element  8  in one joint edge, hereafter referred to as the “strip panel” which cooperates with a locking groove  14  in the other joint edge, hereafter referred to as the “fold panel”, and provides the horizontal locking. 
   The prior art mechanical locking system comprises a separate flexible tongue  15  fixed into a displacement groove  40  formed in one of the joint edges. The flexible tongue  15  has a groove portion P 1 , which is located in the displacement groove  40  and a projecting portion P 2  projecting outside the displacement groove  40 . The projecting portion P 2  of the flexible tongue  15  in one of the joint edges cooperates with a tongue groove formed in the other joint edge. 
   The flexible tongue  15  has a protruding part P 2  with a rounded outer part  31  and a sliding surface  32 , which in this embodiment if formed like a bevel. It has upper  33  and lower  35  tongue displacement surfaces and an inner part  34 . 
   The displacement groove  40  has an upper  42  and a lower  46  opening, which in this embodiment are rounded, a bottom  44  and upper  43  and lower  45  groove displacement surfaces, which preferably are essentially parallel with the horizontal plane HP. 
   The tongue groove  20  has a tongue-locking surface  22 , which cooperates with the flexible tongue  15  and locks the joint edges in a vertical direction D 1 . The fold panel  1 ′ has a vertical locking surface  24 , which is closer to the rear face  62  than the tongue groove  20 . The vertical locking surface  24  cooperates with the strip  6  and locks the joint edges in another vertical direction. The fold panel has in this embodiment a sliding surface  23  which cooperated during locking with the sliding surface  32  of the tongue. 
     FIG. 4   a  shows a cross section A-A of a panel according to  FIG. 4   b  seen from above. The flexible tongue  15  has a length L along the joint edge, a width W parallel to the horizontal plane and perpendicular to the length L and a thickness A in the vertical direction D 1 . The sum of the largest groove portion P 1  and the largest protruding part P 2  is the total width TW. The flexible tongue has also in this embodiment a middle section MS and two edge sections ES adjacent to the middle section. The size of the protruding part P 2  and the groove portion P 1  varies in this embodiment along the length L and the tongue is spaced from the two corner-sections  9   a  and  9   b . The flexible tongue  15  has on one of the edge sections a friction connection  36  which could be shaped for instance as a local small vertical protrusion. This friction connection keeps the flexible tongue in the displacement groove  40  during installation, or during production, packaging and transport, if the flexible tongue is integrated with the floor panel at the factory. 
     FIGS. 5   a  and  5   b  shows the position of the flexible tongue  15  after the first displacement, during the installation, towards the bottom  44  of the displacement groove  40 . The displacement is caused essentially by bending of the flexible tongue  15  in its length direction L parallel to the width W. This feature is essential for this prior art. 
     FIG. 6  shows one embodiment of a vertical folding. A first panel  1 ″ in a first row is connected to a second  1  panel in a second row. The new panel  1 ′ is connected with its long side  5   a  to the long side  5   b  of the first panel with angling. This angling action also connects the short side  4   b  of the new pane with the short side  4   a  of the second panel. The fold panel  1 ′ is locked to the strip panel  1  with a combined vertical and turning motion along the vertical plane VP. The protruding part P 2  has a rounded and or angled folding part P 2 ′ which during folding cooperates with the sliding surface  23  of the folding panel  1 ′. The combined effect of a folding part P 2 ′, and a sliding surface  32  of the tongue which during the folding cooperates with the sliding surface  23  of the fold panel  1 ′ facilitates the first displacement of the flexible tongue  15 . An essential feature of this embodiment is the position of the projecting portion P 2 , which is spaced from the corner section  9   a  and  9   b . The spacing is at least 10% of the length of the joint edge, in this case the visible short side  4   a.    
     FIGS. 7   a - e  shows embodiments of the displaceable tongue  15 , which are applicable according to the invention, besides the bow shaped tongue shown in  FIGS. 4 and 5 . Tongues are preferably made of moulded plastic. Any type of polymer materials could be used such as PA (nylon), POM, PC, PP, PET or PE or similar having the properties described above in the different embodiments. These plastic materials could be when injection moulding is used be reinforced with for instance glass fibre, Kevlar fibre, carbon fibre or talk or chalk. A preferred material is glass fibre, preferably extra long, reinforced PP or POM. 
     FIG. 7   a  shows an embodiment with a first long edge L 1  and a second long edge L 2 . The first long edge has protrusions extending in a plane parallel to the topside  64  of the tongue  15  and with an angle relative the longitudinal direction of the tongue. 
     FIGS. 7   a - b  show the embodiment, in top and in a side view, with a first long edge L 1  and a second long edge L 2 . The first long edge has protrusions  61  extending in a plane parallel to the topside, an upper displacement surface  61 , and rear side, a lower displacement surface, of the tongue and with an angle relative the longitudinal direction of the tongue. The protrusions are preferably bow shaped and, in a particular preferred embodiment, the tongue is provided with a recess  62  at each protrusion  61 . The recess is preferably adapted to the size and shape of the protrusion. 
   The protrusions are preferably provided with a friction connection  63 , most preferably close to or at the tip of the protrusion, which could be shaped for instance as a local small vertical protrusion. This friction connection keeps the flexible tongue in the displacement groove  40  during installation, or during production, packaging and transport, if the displaceable tongue is integrated with the floor panel at the factory. 
     FIG. 7   d  shows one embodiment of the locking system according to the invention illustrating the tongue  15  in the cross section B-B in  FIG. 7   c  and positioned in the displacement groove  40  of a first panel  1  with a combination lock C. The upper and lower displacement surface of the tongue is configured to cooperate with an upper  43  and a lower  45  groove displacement surfaces. The panel comprising a locking strip  6  and a locking element  8  for horizontal locking. The panel  1  is configured to be connected to a second panel  1 ′ in a similar way as the shown in  FIG. 2  or  3 . The upper displacement surface ( 64 ) and/or the lower displacement surface ( 65 ) of the tongue is in one preferred embodiment provided with a bevelled edge, presenting a sliding surface ( 32 ,  31 ) and an inclined locking surface ( 66 ), respectively. The inclined locking surface cooperates preferably with an inclined tongue-locking surface  22  in the tongue groove  20 . The combination lock C, may be connected to a second panel  1 ′ provided with the FG-lock or to a third panel provided with the T-Lock. 
   In the embodiments according to  FIG. 7   d , the displacement groove ( 40 ) is formed in one piece with the core of the panel, but other alternatives are possible. The Displacement groove may be formed in a separate material, for example HDF, which is connected to a wood core in a parquet floor. The displacement groove may be formed of U-shaped plastic or metal sections, which are connected to the panel with for example a snap connection, glue or friction. These alternatives could be used to reduce friction and to facilitate horizontal displacement of the tongue in the displacement grove. The displacement groove may also be treated with a friction reducing agent. These principles may also be applied to the tongue groove. 
   The  FIG. 7   e  shows a casting gate  71  which is cut of before insertion into the displacement groove. 
     FIGS. 8   a - e  show different installation pattern, which are possible to install with the locking system and set of floor panels according to the invention.  FIG. 8   a  shows a pattern with three floor panels connected at the short edges to a long edge of a panel with mirror inverted connecting devices, A and B-panels, which is explained below and in  FIGS. 9   a - e . The pattern consists of a group of three panels in first direction, surrounded by groups of three panels in a perpendicular direction.  FIG. 8   b  show a quadratic panel connected at all edges to a long edge of a rectangular.  FIG. 8   c  shows a pattern in which a panel in a first direction is connected at an edge to three panels in a second perpendicular direction, which is connected to a first long edge of a fourth panel in the first direction, whose opposite edge is connected to three panels in the second direction, continued in a repeating manner.  FIG. 8   d  shows a pattern comprising a group of four connected quadratic panels surrounded and connected to the long edges of rectangular panels.  FIG. 8   e  shows a traditional herringbone pattern. All these installation patterns involve connecting of a short side to a long side. The invention provides a solution, which make it possible to install the patterns with a vertical folding method, connecting the panels with a strong joint in the vertical and the horizontal direction. The pattern involves joining of, e.g., (cf.  FIGS. 9 ,  12 ):
         a short edge provided with a combination lock C to a long edge provided with the T-lock   a short edge provided with the FG-lock to a long edge provided with the combination lock C   a long edge provided with the combination lock C to a long edge with the T-lock   a short edge provided with the FG-lock to a short edge provided with the combination lock C   an edge of a quadratic panel provided with a combination lock C to another edge of a quadratic panel provided with the T-lock   an edge of a quadratic panel provided with a combination lock C to another edge of a quadratic panel provided with the FG-lock   an edge of a quadratic panel provided with a combination lock C to a long edge provided with the FG-lock   an edge of a quadratic panel provided with a combination lock C to a long edge provided with the T-lock   an edge of a quadratic panel provided with a FG-lock to a long edge provided with the combination lock C   an edge of a quadratic panel provided with a T-lock to a long edge provided with the combination lock C   The short edge of an A-panel are preferably joined to the long edge of a B-panel, as is common for installation with A and B-panels.       
   One way to enable connecting of a short side to a long side is to provide A-panels and B-panels with mirror inverted connecting devices, as is shown in  FIGS. 9   a - d . Two adjacent edges of the panels are provided with the combination lock C, one edge with the FG-Lock and one edge provided with the T-lock. The three types of connecting devices C, FG, T are distributed mirror inverted on the A and on the B panel.  FIG. 9   a  shows a rectangular A-panel with long and short edges.  FIG. 9   b  shows a rectangular B-panel with long and short edges.  FIG. 9   a  shows a quadratic A-panel and  9   b  shows a quadratic B-panel. 
     FIG. 10   a  shows an embodiment wherein a displaceable flexible tongue  15  and a displacement groove  40  is provided on fourth connecting device on a fourth panel  4  comprising a locking groove  14 . This makes it possible to connect a short side, with the fourth connecting device, of a floor panel  4  to a long side of fifth panel  5  comprising a standard connecting device, comprising locking element  8  and tongue groove  11  for connection by angling, with vertical folding. The problem is that this solution creates a thin section between the bottom of the displacement groove  40  and the locking groove  14 , resulting in a weak joint. 
     FIG. 10   b  shows an embodiment wherein the flexible tongue is removed and the joint is only locking in the horizontal direction. 
     FIGS. 10   c - d  show how the principles of the invention may be applied to tongue-groove joint, without any horizontally locking.  FIG. 10   c  illustrates a panel with a flexible tongue  15  and a displacement groove  40  cooperating with a tongue  10  of a tongue panel.  FIG. 10   d  illustrates a groove panel with a flexible tongue groove  20  cooperating with the flexible tongue  15 . The groove panel may be connected also to a tongue panel with a tongue cooperating with the groove  11 . 
     FIG. 11  shows in 10 steps a preferred connection method of A and B-panels, quadratic and with long and short edges in an advanced pattern. Short edges are joined to long edges and the quadratic panels are at all edges joined with long edges. 
     FIG. 12   a  shows an enlarged part of the pattern in  FIG. 11  and how the combination loc is distributed to generate the A and B-panels and to enable the pattern. 
     FIG. 12   b  shows how the combination loc is distributed to generate the quadratic A and B-panels. The panels are connected in manner avoiding a row with several CFG-joints, which is a joint between a combination lock against to a FG-lock, in a line. This is an advantage, since a CT-joint, which is a joint between the combination loc C to a T-lock, offers a stronger connection in the vertical direction. Consequently it is preferred that every second joint in a line is a CFG-joint and provided there between is a CT-joint. The figure also shows an embodiment of the distribution of the connecting devices to provide, which make it possible to connect several quadratic panels to a long edges of a rectangular panel. Several edges of the quadratic panels with the combination lock may be connected to a long edge with the T-lock. Quadratic panels, with edges in a line having the FG-lock and the T-lock, may be connected to a long edge with the combination lock C. 
   A disadvantage with the CT-joint is that the flexible tongue pushes the panels apart and possible causing a gap between the panels. One solution to avoid this is to adapt the stiffness of the flexible tongue, so that the force pushing the panels apart is reduced, but this also influence the final position in a CFG-joint. A second solution is that the flexible tongue is configured to be cracked or destroyed when the tongue pushes it into the displacement groove. A third solution is a strong locking element with guiding surfaces, facilitating the installation. A fourth solution is to dissolve or remove the tongue. It is also possible to provide the joint edges with bevels or decorative grooves, which hidden the gap. 
   The invention is not restricted to the above-mentioned illustrative embodiments, but is naturally applicable to other embodiments within the scope of the following patent claims, and equivalents thereof.