Patent Publication Number: US-7913473-B2

Title: Method for placing and mechanically connecting panels

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a U.S. National Stage of International Patent Application No. PCT/EP2006/004998 filed May 24, 2006, and claims priority of German Patent Application No. 10 2005 024 366.5 filed May 27, 2005. Moreover, the disclosure of International Patent Application No. PCT/EP2006/004998 is expressly incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a method for laying and mechanically connecting panels in rows parallel to one another, the panels having respectively a first pair of side edges lying opposite one another and a second pair of side edges lying opposite one another, a first pair of locking elements being assigned to the first pair of side edges as well as a second pair of locking elements being assigned to the second pair of side edges, the pairs of locking elements being embodied essentially in the form of a tongue and a groove. It is possible to lock two adjacent panels to one another with the aid of the locking elements in a direction running orthogonally to the panel plane as well as in a direction running parallel to the panel plane and orthogonally to the respective side edge. It is also possible to connect the tongue and the groove of the first pair of locking elements to one another by pivoting them into one another. 
     2. Discussion of Background Information 
     A method for laying and mechanically connecting panels of this type is known, e.g., from EP 0 969 164 B1. With this method a panel, which is to be added to a panel row that is to be newly laid, is brought to a panel that has already been laid in the panel row to be newly laid. 
     Next, the panel that has already been laid in the panel row that is to be newly laid is pivoted relative to the panel rows that have already been laid, but without releasing the engagement with the panels that have already been laid. 
     Finally, one of the short sides of the panel that is to be newly laid is brought to the free short side of the panel that has already been laid in the panel row that is to be newly laid, wherein the panel planes of these two panels form an angle with one another. 
     After the engagement of the engaging elements of the panel that is to be newly laid with the panel that has already been laid in the panel row that is to be newly laid, the panel planes of the panel that is to be newly laid, of the panel that has already been laid of the panel row that is to be newly laid and of the panels of the panel rows that have already been laid run respectively in pairs at an angle to one another. 
     In a next step the panel that is to be newly laid and the panel that has already been laid in the panel row that is to be newly laid are pivoted at the same time towards the floor area on which the panel rows are already laid to rest. In order to bring the engagement elements on the long side of the panel that is to be newly laid into engagement with the engagement elements of the panel row that was last laid and to bring the panel planes of the panel that is to be newly laid and the panel that has already been laid in the panel row that is to be newly laid into alignment with the panel plane of the panel rows that has already been laid. 
     This known method has the disadvantage of being very laborious and difficult to carry out. Either two floorers are required, one of whom manipulates the panel that is to be newly laid in the panel row and the other manipulates the panel that has already been laid in the panel row, or one person must manipulate the panel that is to be newly laid in the panel row with one hand and the panel that has already been laid in the panel row with the other hand. The former case is laborious, because one person cannot lay the panels alone. In the second case, however, a single floorer is faced with the problem that particularly manipulating the panel that is to be newly laid is extremely complicated and requires great strength. This is because the panel that is to be newly laid must be arranged in a very specific spatial orientation and into a very specific relative position to the panel that has already been laid in the panel row, which is to be newly laid, while also taking into account the leverages stemming from the panels that are usually approximately 1.2 m long, 0.2 m wide, and approximately 0.4 kg in weight. 
     SUMMARY OF THE INVENTION 
     The aspect of the invention is therefore to disclose a method for laying and mechanically connecting panels of the type mentioned at the outset, wherein the method can be carried out more easily and in particular by one floorer. 
     This aspect is attained according to the invention by a method of the type mentioned at the outset. Initially, in a first step, a plurality of panels of a panel row that is to be newly laid, and preferably all of the panels of the panel row that is to be newly laid, are connected to one another in pairs by way of locking elements of their respective second pairs of locking elements. In a second step, the panels connected to one another of the panel row that is to be newly laid are connected to the panels of the panel row that has already been laid by pivoting locking elements of their respective first pairs of locking elements into one another. This may be performed by working in sections, in one or more sub-steps, beginning at one of the ends of the panel row that is to be newly laid and utilizing a torsional flexibility of the panels about an axis running parallel to the first pair of side edges, along to the other of its ends. In this method two properties of the panels are utilized, which had not hitherto been considered for use in the course of laying the panels: the strength of the engagement of the locking elements; and the torsional flexibility of the panels about an axis running parallel to its first pair of side edges. 
     The strength of the engagement of the locking elements of two panels connected to one another is utilized in the first step to form a type of “super panel” from a plurality of panels of a panel row that is to be newly laid. The width of the “super panel” is equal to the measurement of the panels along their second pair of side edges. The length of the super panel is equal to a multiple of the measurement of the panels along their first pair of side edges corresponding to the plurality of panels. In the further manipulation of this super panel in the second step of the laying process of the invention, the individual panels of this super panel do not move relative to one another by themselves due to the strength of the engagement of the locking elements. Although this is not necessarily required, it is recommended to assemble the super panel in the direct vicinity of the panel row that was last laid. 
     The torsional flexibility of the panels, and thus also of the super panel, is utilized in the second step of the laying method according to the invention to bring the locking elements of the super panel into engagement with the corresponding locking elements of the panel row that was last laid. Although, in principle, the entire super panel could be angled relative to the panel row that has already been laid, a plurality of floorers would be necessary to pivot the engagement elements into one another. According to the invention one therefore begins with a section adjacent to a longitudinal end of the super panel and allows the locking elements of this section to come into engagement with the locking elements of the corresponding section of the panel row that has already been laid. However, this does not mean that once the bringing into engagement has been completed, the panel plane in the area of this section is already aligned with the panel plane of the panel rows that have already been laid. In fact, the mere engagement of the locking elements is sufficient. In this manner one works one&#39;s way in sections to the other longitudinal end of the super panel, whereby, due to their torsional flexibility about an axis running parallel to the first pair of side edges, the panels or the super panel perform a gentle “wave movement” from the one longitudinal end of the super panel to the other longitudinal end of the super panel. Once the bringing into engagement the locking elements has been completed, if the super panel has not been pivoted towards the floor surface due to its dead weight, thus completely pivoting the locking elements for connecting the super panel to the panel row already laid into one another, the floorer can accomplish this now, preferably working again from one longitudinal end of the super panel to the other longitudinal end. To sum up, it could be said that the super panel and the panel row that was last laid are connected to one another in a “zipper-like” manner according to the laying method of the invention. 
     In the manner described above, the panels can also be easily laid by a single floorer without complicated handling. 
     In producing the super panel it is preferred that the panels of the panel row that is to be newly laid be aligned to one another to prepare for the first step or in the course of carrying out the first step. To make it easier to pivot the locking elements into one another, it is advantageous if the panels are laid in an orientation such that the panels of the panel row that has already been laid present their groove to the panels of the panel row that is to be newly laid. In this case, the alignment of the panels of the panel row that is to be newly laid can be carried out by using the lip near the visible surface of the panels of the panel row that has already been laid as a stop for the tongue of the panels of the panel row that is to be newly laid. 
     The method according to the invention can be carried out in a particularly simple manner if the torsional flexibility of the panels about an axis running essentially parallel to their first pair of side edges is at least 2°, preferably at least 4°, and even more preferably at least 6°, per meter of length of the panel. This torsional flexibility of a panel can be determined in a measurement independent of the laying, e.g., by clamping a panel of a predetermined length on its two short side edges and then pivoting these two short side edges in the opposite direction of rotation to one another, but without destroying the panel, in particular its visible surface. The value of the angle formed by the two short side edges of the panel determined in this manner then needs only to be divided by the value of the length of the panel measured in meters. 
     As indicated above, the panels are, e.g., rectangular panels, having the first pair of side edges assigned to the long side of the rectangle and the second pair of side edges assigned to the short side of the rectangle. However, in principle it is also conceivable to perform the laying method according to the invention with square panels. 
     It is advantageous to strongly lock the two adjacent panels, by the locking elements utilized in the laying method according to the invention, if the first pair of locking elements and/or the second pair of locking elements is embodied in one piece with a core of the panel. 
     Although, in principle, the laying method according to the invention can also be used with panels having lips of equal length delimiting the groove, in the further development of the invention it is proposed for the groove of the first pair of locking elements to have two lips delimiting the groove, the lip distant from the visible surface of the panel being longer than the lip close to the visible surface of the panel. It can thus be ensured that the tongue of the one panel does not accidentally come into engagement with the relatively rough subsurface of the laying area while it is pivoted into the groove of the other panel, thereby being possibly exposed to the risk of damage. Instead, the tongue can be placed on the longer lower groove-delimiting lip and, sliding thereon, pivoted into the groove. This can be used to simplify the alignment of the panels relative to one another when connecting the panels of the panel row that is to be newly laid to the super panel. 
     The method according to the invention is particularly advantageous in the use of panels in which the tongue and groove of the second pair of locking elements can also be connected to one another by pivoting into one another. Although in principle the method according to the invention can also be used with panels in which the tongue and groove of the second pair of locking elements can be connected to one another essentially by pushing them together in a planar manner, other laying methods that can easily be carried out by a single floorer also exist for panels of this type. 
     To simplify the producibility of the panels, it is proposed for the first pair of locking elements and the second pair of locking elements to be embodied in an essentially identical manner. 
     The method according to the invention can be used particularly advantageously with panels that have a core of a wood-fiber material or a wood-chip material, which if desired is provided with a decorative layer on the side facing the visible surface of the panels and/or with a counteracting layer on the side facing away from the visible surface of the panels. For example, MDF boards (medium density fiberboard) or HDF boards (high density fiberboard) are thereby used as wood-fiber material and, e.g., OSB boards (oriented structural board) as wood-chip material. 
     It should also be added that the panels are preferably flooring panels. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in more detail below based on an exemplary embodiment by way of the attached drawings. They show: 
         FIG. 1  shows a rough diagrammatic plan view of a panel that can be laid with the aid of the method according to the invention; 
         FIG. 2  shows a cross-sectional view along the lines II-II or II′-II′ in  FIG. 1 ; 
         FIG. 3  shows a diagrammatic front view of the panel according to  FIG. 1  in a view from the direction of the arrow III in  FIG. 1  to explain the term of torsional flexibility; 
         FIGS. 4 and 5  show a diagrammatic plan views of panels laid on a subsurface to explain the method according to the invention; 
         FIG. 6  shows a view similar to  FIG. 2  to explain the alignment of a panel row to be newly laid with the aid of the panel row last laid; and 
         FIGS. 7   a  through  7   c  show views similar to  FIG. 2  to explain the pivoting into one another of the locking elements of two adjacent panels. 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION 
     In  FIG. 1  a panel that can be laid with the aid of the method according to the invention is designated in general by panel  10 . The panel  10  is embodied in a rectangular manner and comprises two side edges  12  and  14 , running parallel to one another, of the long sides of the panel  10  running in the longitudinal direction L, and two side edges  16  and  18 , running parallel to one another, of the short sides of the panel  10  running in the transverse direction Q. Both pairs of side edges  12 / 14  and  16 / 18  are provided with locking elements that are embodied essentially in the form of a groove  20  and a tongue  22  (see  FIG. 2 ). 
     The groove  20  is limited by an upper lip  20   a  near to the visible surface  24  of the panel  10  and by a lower lip  20   b  near to the base area  26  of the panel  10  facing away from the visible surface  24 , i.e., distant from the visible surface  24 . In the exemplary embodiment shown the lower lip  20   b  is embodied longer than the upper lip  20   a  and projects beyond the side edges  12 ,  16  of the panel (see  FIG. 2 ). The groove base  20   c  of the groove  20  is indicated by a dotted line in  FIG. 1 . A locking projection  20   d  projects from the lower lip  20   b  in the vertical direction H of the panel  10  on which projection a locking surface  20   e  is embodied. Furthermore, a groove-limiting surface  20   f  of the lower lip  20   b  running essentially parallel to the visible surface  24  and a groove-limiting surface  20   g  of the upper lip  20   a  likewise running essentially parallel to the visible surface  24  should also be noted. 
     The tongue  22  begins at a boundary line  22   c , which is indicated by a broken line in  FIG. 1 , and designates the end of the main body of the panel  10 . Furthermore, an engagement projection  22   a  is provided on the tongue  22 , which projection engages under the upper lip  20   a  and in the connected state of two panels shown in  FIG. 7   c  bears with a mating surface  22   g  essentially parallel to the visible surface  24  against the groove-limiting surface  20   g  of the groove  20 . Furthermore, the tongue  22  has a locking projection  22   d . On the one hand, a mating surface  22   f  running essentially parallel to the visible surface  24  of the panel  10  is embodied on the locking projection  22   d , with which mating surface the tongue  22  bears against the lower groove-limiting surface  20   f  of the lower lip  20   b  in the locked state of two adjacent panels according to  FIG. 7   c . On the other hand, a locking surface  22   e  is provided on the locking projection  22   d , which locking surface bears against the locking surface  20   e  of the groove  20  in the locked state according to  FIG. 7   c . Furthermore, a mating surface  22   h  is also provided on the face of the tongue  22 , which mating surface runs essentially orthogonally to the visible surface  24  of the panel  10  and bears against the face  20   h  of the groove  20  in the locked state according to  FIG. 7   c.    
     In the locked state of two adjacent panels shown in  FIG. 7   c , the interaction of the surface pairs  20   e / 22   e  and  20   h / 22   h  effects a locking of the two panels to one another in a direction that runs orthogonally to the vertical direction H of the panel and at the same time also orthogonally to the respectively observed side edge. However, the interaction of the surface pairs  20   g / 22   g  and  20   f / 22   f  running essentially parallel to the visible surface  24  of the panel  10  effects a locking of the two panels in the vertical direction H of the panel  10 . 
     As shown in  FIG. 2 , the groove  20  is recessed into a core  30  of the panel  10 , which core can be made, e.g., of a wood-fiber material, preferably a medium density fiberboard (MDF) or a high density fiberboard (HDF), or a wood-chip material, e.g., an OSB board. The core  30  can be provided with a decorative layer  32  on the visible surface  24  of the panel  10 , which decorative layer comprises, e.g., one or more paper layers, the topmost of which can be printed with a desired pattern and which are impregnated with synthetic resin and compressed to form a laminate layer. Analogously, the base surface  26  of the panel  10  can be covered with a counteracting layer  34  which can be made from a plurality of paper layers analogously to the decorative layer  32 . The decorative layer  32  as well as the counteracting layer  34  preferably extend over the entire visible surface  24  or base surface  26  of the panel  10 . The base area  26  can be free of the counteracting paper  34  only in the area  26   a  shown by shading in  FIG. 2 , i.e., the area adjacent to the lower lip  20   b , in order to avoid an undesirable deflection of the lower lip  20   b  downwards in  FIG. 2 . 
     It should also be noted that the panel  10  is provided with a chamfer  36  in the area of the side edges  12 ,  14 ,  16 ,  18  adjacent to the visible surface  24 . The chamfer produces a V joint in interaction with the corresponding chamfer of an adjacent panel. The V joint has a mainly aesthetic function. 
     As shown in  FIG. 3 , the panels described above have the property that they can be twisted about their longitudinal axis L to a certain extent. Therefore, if the panel  10  is clamped at both short side edges  16  and  18  and these two side edges are twisted in opposite directions about an axis running parallel to the longitudinal axis L of the panel  10 , an angle α is produced between the visible surface  24  in a section adjacent to the side edge  16  and the visible surface  24  in a section adjacent to the side edge  18 . Of course, the same applies analogously to the base area  26  in the sections adjacent to the side edges  16  and  18 . If this torsion angle α is applied to a standard length of the panel  10 , e.g., a length of 1 m, then this value measured in the unit “°/m” is a measure of the torsional flexibility of the panel  10 . 
     How this property of torsional flexibility is used by the method according to the invention to lay and mechanically connect the panels is explained below with reference to  FIGS. 4 and 5 . 
       FIG. 4  shows a plurality of rows of panels arranged parallel to one another, namely two already laid panel rows  40  and  42 , of which the panel row  42  is the panel row last laid, and a panel row  44  to be newly laid. 
     In a first step of the method according to the invention, the panels  10 ′,  10 ″ . . . of the panel row  44  to be newly laid are connected to one another in pairs on their short sides  16 ′/ 18 ″,  16 ″/ 18 ″″, . . . to form a super panel  46 . It should thereby be ensured that the long sides  12 ′,  14 ′,  12 ″,  14 ″, . . . of the panels  10 ′,  10 ″ are oriented in alignment with one another. 
     If the panels are laid such that the panels of the panel row  42  respectively laid last present their groove side edge  12  in each case to the panels of the panel row  44  to be newly laid, this alignment of the panels of the panel row  44  to be newly laid can be easily carried out at the panel row  42  last laid, as shown in  FIG. 6 . To this end the panels of the panel row to be newly laid are placed with the tongue  22  on the lower groove-limiting lip  20   b  of the panels of the panel row  42  already laid and the panels of the panel row  44  to be newly laid are pushed towards the panels of the panel row  42  already laid until the face  22   i  of the engagement projection  22   a  of the tongue  22  comes to rest on the face  20   h  of the upper groove-limiting lip  20   a  of the panels of the panel row  42  already laid. This state is shown in section in  FIG. 6  and in plan view for the entire panel row  44  to be newly laid or the super panel  46  in  FIG. 4 . 
     In a second step of the laying method according to the invention the super panel  46  or the panel row  44  to be newly laid is now connected to the panel row  42  last laid. A floorer hereby works his way from one longitudinal end  46   a  of the super panel  46 , in FIG.  5 , e.g., the left longitudinal edge of the super panel  46 , to the respectively other longitudinal edge  46   b  of the super panel  46  and guides the super panel  46  with its engagement projection  22   a  in sections into the groove  20  of the panel row  42  already laid (see  FIG. 7   a ). This procedure by sections is made possible by the above-mentioned torsional flexibility of the panels  10 . It is discernible in  FIG. 5  that the super panel  46  on the end  46   a  of the left in  FIG. 5  has already been brought together with the panels of the panel row laid last, while the end  46   b  on the right in  FIG. 5  is still in the alignment position according to  FIG. 6 . 
     As already stated above, the floorer now works his way from the one long end  46   a  of the super panel  46  to the other long end  46   b , thereby guiding the engagement projection  22   a  of the super panel  46  in a zipper-like manner into the groove  20  of the panel row  42  already laid. 
     With this first sub-step of the second step of the method according to the invention, the mechanical connection between the panel row  44  to be newly laid or the super panel  46  on the one hand and the panel row  42  last laid does not yet need to have been fully completed. Thus it is not necessary, immediately after introducing the engagement projection  22   a  into the groove  20  of the panel row last laid, to pivot the super panel  46  completely to the subsurface U until it bears on the subsurface U, as shown in  FIG. 7   c . Instead, it is sufficient to pivot the super panel  46  by hand into an intermediate position shown in  FIG. 7   b , or to allow it to pivot into this position itself due to the force of gravity, in which position the locking surfaces  20   e  and  22   e  bear against one another only loosely. Once the super panel  46  is in this intermediate position according to  FIG. 7   b  over its entire length, then in a second sub-step of the second step of the laying method according to the invention, again working from the one long end  46   a  of the super panel  46  to the other long end  46   b  in sections, the final locking position according to  FIG. 7   c  can be produced. 
     When the laying technique described above is used, the panels  10  can be easily laid by a single floorer in a simple manner that is economical with material.