Abstract:
Rectangular floor panels, a fastening system for joining the panels, and a method for laying and interlocking the panels are disclosed. The panels are provided complementary, form-fitting retaining profiles extending over the length of the sides. The complementary edges of the panels allow two adjacent panels to be positively joined such that displacement of the panels away from one another is prevented, while enabling articulation of the panels with respect to one another at the joint location. The method of installation provides for installing a new panel to a first row and a panel in a second row by first joining the new panel to the panel of the second row at its short side, followed by pivoting the new panel upwards out of the plane of the laid panels along its long side, along with at least the adjacent end of the first panel in the second row, into an inclined position, and sliding the new panel into the retaining profile of the panels in the first row. The new panel and the raised end of the panel in the second row are then pivoted down into the plane of the laid panels. Laying of panels continues according to this process until the complete floor assembly has been laid.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation of co-pending and co-owned U.S. patent application Ser. No. 09/609,251, filed with the U.S. Patent and Trademark Office on Jun. 30, 2000 entitled “Method for Laying and Interlocking Panels”, which is a continuation of PCT/DE00/00870, filed in Germany by the inventor herein, the specifications of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The invention relates to a method for laying and interlocking panels, particularly via a fastening system consisting of positive retaining profiles provided on the narrow sides of the panels, which extend over the length of the narrow sides and are provided with joint projections or complementary joint recesses.  
         [0004]     2. Background of the Prior Art  
         [0005]     German utility model G 79 28 703 U1 describes a generic method for laying and interlocking floor panels with positive retaining profiles. These retaining profiles can be connected to each other by means of a rotary connecting movement. However, the disadvantage is that, in order to lay a second row of panels that is to be attached to a laid first row of panels, the second row first has to be completely assembled. The technical teaching to be taken from utility model G 79 28 703 U1 is that a first row of panels initially has to be laid ready horizontally and that a start is then made with a second panel in a second row, which has to be held at an angle and slid into a groove formed in the first panel row. The second panel has to be held at this angle, so that a third panel can be connected to the second panel. The same applies to the subsequent panels that have to be connected to each other in the second row. Only once all the panels of the second panel row have been pre-assembled in an inclined position can the entire second panel row be swung into horizontal position, this causing it to interlock with the first panel row. The unfavorable aspect of the laying method required for this panel design is the fact that several persons are required in order to hold all the panels of a second panel row in an inclined position for pre-assembly and then to jointly lower the second panel row into the laying plane.  
         [0006]     Another method for laying and interlocking panels is known from EP 0 855 482 A2. In this case, panels to be laid in the second row are again connected to the panels of a first row in an inclined position. Adjacent panels of the second row are initially interlocked with the panels of the first row, leaving a small lateral distance between them. In this condition, the panels of the second row can be displaced along the first row. Retaining profiles provided on the short narrow sides of the panels are pressed into each other by sliding two panels of the second row against each other. Disadvantageously, the retaining profiles are greatly expanded and elongated during this process. Even during assembly, the retaining profiles already suffer damage that impairs the durability of the retaining profiles. The retaining profiles designed and laid according to the teaching of EP 0 855 482 A2 are not suitable for repeated laying. For example, retaining profiles molded from HDF or MDF material become soft as a result of the high degree of deformation to which the retaining profiles are subjected by the laying method according to EP 0 855 482 A2. Internal cracks and shifts in the fiber structure of the HDF or MDF material are responsible for this.  
         [0007]     The object of the invention is thus to simplify the method for laying and interlocking panels and to improve the durability of the fastening system.  
       SUMMARY OF THE INVENTION  
       [0008]     According to the invention, the object is solved by a method for laying and interlocking rectangular, plate-shaped panels, particularly floor panels, the opposite long narrow sides and opposite short narrow sides of which display retaining profiles extending over the length of the narrow sides, of which the opposite retaining profiles are designed to be essentially complementary to each other, where a first row of panels is initially connected on the short narrow sides, either in that the complementary retaining profiles of a laid panel and a new panel are slid into each other in the longitudinal direction of the short narrow sides, or in that the retaining profile of a new panel is initially inserted in an inclined position relative to the laid panel having the complementary retaining profile of the laid panel and subsequently interlocked, both in the direction perpendicular to the connected narrow ends and in the direction perpendicular to the plane of the laid panels, by pivoting into the plane of the laid panel, the next step being to lay a new panel in the second row, in that the retaining profile of its long narrow side is initially inserted into the retaining profile of the long narrow side of a panel of the first row by positioning at an angle relative to it and subsequently pivoting into the plane of the laid panels, and where a new panel, the short narrow side of which must be interlocked with the short narrow side of the panel laid in the second row and the long narrow side of which must be connected to the long narrow side of a panel laid in the first row, is first interlocked with the panel of the second row at its short narrow end, the new panel then being pivoted upwards out of the plane of the laid panels along the long narrow side of a panel laid in the first row, where the panel of the second row that was previously interlocked with the new panel on the short narrow side is also pivoted upwards, at least at this end, together with the new panel, into an inclined position in which the long retaining profile of the new panel can be inserted into the complementary retaining profile of the panel laid in the first row and, after insertion, the inclined new panel and the panel interlocked with the new panel on a short narrow side in the second row are pivoted into the plane of the laid panels.  
         [0009]     According to the new method, panels to be laid in the second row can be fitted by a single person. A new panel can be interlocked both with panels of a first row and with a previously laid panel of the second row. This does not require interlocking of the short narrow sides of two panels lying in one plane in a manner that expands and deforms the retaining profiles.  
         [0010]     The last panel laid in the second row can be gripped by its free, short narrow end and can be pivoted upwards into an inclined position about the interlocked, long narrow side as the pivoting axis. The panel is slightly twisted about its longitudinal axis in this process. The result of this is that the free, short narrow end of the panel is in an inclined position and the inclination decreases towards the interlocked, short narrow end of the panel. Depending on the stiffness of the panels, this can result in more or less strong torsion and thus in a greater or lesser decrease in the inclination. In the event of relatively stiff panels, the inclination can continue through several of the previous panels in the second row.  
         [0011]     When laying, it is, of course, not necessary for the first row to be laid completely before making a start on laying the second row. During laying, attention must merely be paid to ensuring that the number of elements in the first row is greater than that in the second row, and so on.  
         [0012]     The method can be realized particularly well when using thin, easily twisted panels. The inclination of a thin panel located in the second row decreases over a very short distance when subjected to strong torsion. The non-twisted remainder of a panel, or of a panel row, located in the laying plane, is securely interlocked. Only on the short, inclined part of the last panel of the second row can the retaining profiles of the long narrow sides become disengaged during the laying work. However, they can easily be re-inserted together with the new panel attached at the short narrow side.  
         [0013]     A particularly flexible and durable design is one consisting of rectangular, plate-shaped panels that display complementary retaining profiles extending over the length of the narrow sides on narrow sides parallel to each other, where one retaining profile is provided in the form of a joint projection with a convex curvature and the complementary retaining profile in the form of a joint recess with a concave curvature, where each joint projection of a new panel is inserted into the joint recess of a laid panel, expanding it only slightly, and the new panel is finally interlocked by pivoting into the plane of the laid panel. The deformation of the retaining profiles required for laying and interlocking is considerably smaller than with retaining profiles that have to be pressed together perpendicular to their narrow sides in the laying plane. Advantageously, the joint projection does not protrude from the narrow side by more than the thickness of the panel. In this way, another advantage lies in the fact that the retaining profile can be milled on the narrow side of a panel with very little waste.  
         [0014]     When laid, the retaining profiles of the long narrow sides of two panels, which can also be referred to as form-fitting profiles, form a common joint, where the upper side of the joint projection facing away from the substrate preferably displays a bevel extending to the free end of the joint projection, and where the bevel increasingly reduces the thickness of the joint projection towards the free end and the bevel creates freedom of movement for the common joint.  
         [0015]     The design permits articulated movement of two connected panels. In particular, two connected panels can be bent upwards at the point of connection. If, for example, one panel lies on a substrate with an elevation, with the result that one narrow side of the panel is pressed onto the substrate when loaded, and the opposite narrow side rises, a second panel fastened to the rising narrow side is also moved upwards. However, the bending forces acting in this context do not damage the narrow cross-sections of the form-fitting profiles. An articulated movement takes place instead.  
         [0016]     A floor laid using the proposed fastening system displays an elasticity adapted to irregularly rough or undulating substrates. The fastening system is thus particularly suitable for panels for renovating uneven floors in old buildings. Of course, it is also more suitable than the known fastening system when laying panels on a soft intermediate layer.  
         [0017]     The design caters to the principle of “adapted deformability”. This principle is based on the knowledge that very stiff, and thus supposedly stable, points of connection cause high notch stresses and can easily fail as a result. In order to avoid this, components are to be designed in such a way that they display a degree of elasticity that is adapted to the application, or “adapted deformability”, and that notch stresses are reduced in this way.  
         [0018]     Moreover, the form-fitting profiles are designed in such a way that a load applied to the upper side of the floor panels in laid condition is transmitted from the upper side wall of the joint recess of a first panel to the joint projection of the second panel and from the joint projection of the second panel into the lower-side wall of the first panel. When laid, the walls of the joint recess of the first panel are in contact with the upper and lower side of the joint projection of the second panel. However, the upper wall of the joint recess is only in contact with the joint projection of the second panel in a short area on the free end of the upper wall of the joint recess. In this way, the design permits articulated movement between the panel with the joint recess and the panel with the joint projection, with only slight elastic deformation of the walls of the joint recess. In this way, the stiffness of the connection is optimally adapted to an irregular base, which inevitably leads to a bending movement between panels connected to each other.  
         [0019]     Another advantage is seen as lying in the fact that the laying and interlocking method according to the invention is more suitable for repeated laying than the known methods, because the panels display no damage to the form-fitting profiles after repeated laying and after long-term use on an uneven substrate. The form-fitting profiles are dimensionally stable and durable. They can be used for a substantially longer period and re-laid repeatedly during their life cycle.  
         [0020]     Advantageously, the convex curvature of the joint projection and the concave curvature of the joint recess each essentially form a segment of a circle where, in laid condition, the center of the circle of the segments of the circle is located on the upper side of the joint projection or below the upper side of the joint projection. In the latter case, the center of the circle is located within the cross-section of the joint projection.  
         [0021]     This simple design results in a joint where the convex curvature of the joint projection is designed similarly to the ball, and the concave curvature of the joint recess similarly to the socket, of a ball-and-socket joint, where, of course, in contrast to a ball-and-socket joint, only planar rotary movement is possible and not spherical rotary movement.  
         [0022]     In a favorable configuration, the point of the convex curvature of the joint projection of a panel that protrudes farthest is positioned in such a way that it is located roughly below the top edge of the panel. This results in a relatively large cross-section of the joint projection in relation to the overall thickness of the panel. Moreover, the concave curvature of the joint recess offers a sufficiently large under-cut for the convex curvature of the joint projection, so that tensile forces acting in the laying plane can hardly move the panels apart.  
         [0023]     The articulation properties of two panels connected to each other can be further improved if the inside of the wall of the joint recess of a panel that faces the substrate displays a bevel extending up to the free end of the wall and the wall thickness of this wall becomes increasingly thin towards the free end. In this context, when two panels are laid, the bevel creates space for movement of the common joint. This improvement further reduces the amount of elastic deformation of the walls of the joint recess when bending the laid panels upwards.  
         [0024]     It is also expedient if the joint recess of a panel for connecting to the joint projection of a second panel can be expanded by resilient deformation of its lower wall and the resilient deformation of the lower wall occurring during connection is eliminated again when connection of the two panels is complete. As a result, the form-fitting profiles are only elastically deformed for the connection operation and during joint movement, not being subjected to any elastic stress when not loaded.  
         [0025]     The ability also to connect the short narrow ends of two panels in articulated fashion benefits the resilience of a floor covering.  
         [0026]     The form-fitting profiles preferably form an integral part of the narrow sides of the panels. The panels can be manufactured very easily and with little waste.  
         [0027]     The laying method is particularly suitable if the panels consist essentially of an MDF (medium-density fiberboard), HDF (high-density fiberboard), or particleboard material. These materials are easy to process and can be given a sufficient surface quality by means of cutting processes, for example. In addition, these materials display good dimensional stability of the milled profiles.  
         [0028]     The various features of novelty that characterize the invention will be pointed out with particularity in the claims of this application.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]     An example of the invention is illustrated in a drawing and described in detail below on the basis of FIGS.  1  to  9 . The figures show the following:  
         [0030]      FIG. 1 —Part of a fastening system on the basis of the cross-sections of two panels prior to connection,  
         [0031]      FIG. 2 —The fastening system as per  FIG. 1  in assembled condition,  
         [0032]      FIG. 3 —A connecting procedure, where the joint projection of one panel is inserted in the joint recess of a second panel in the direction of the arrow and the first panel is subsequently locked in place by a rotary movement,  
         [0033]      FIG. 4 —A further connecting procedure, where the joint projection of a first panel is slid into the joint recess of a second panel parallel to the laying plane,  
         [0034]      FIG. 5 —The fastening system in laid condition as per  FIG. 2 , where the common joint is moved upwards out of the laying plane and the two panels form a bend,  
         [0035]      FIG. 6 —The fastening system in laid condition as per  FIG. 2 , where the common joint is moved downwards out of the laying plane and the two panels form a bend,  
         [0036]      FIG. 7 —A fastening system in the laid condition of two panels, with a filler material between the form-fitting profiles of the narrow sides,  
         [0037]      FIG. 8 —A perspective representation of the method for laying and interlocking rectangular panels,  
         [0038]      FIG. 9 —An alternative method for laying and interlocking rectangular panels.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0039]     According to the drawing, fastening system  1 , required for the method for laying and interlocking rectangular panels, is explained based on oblong, rectangular panels  2  and  3 , a section of which is illustrated in  FIG. 1 . Fastening system  1  displays retaining profiles, which are located on the narrow sides of the panels and designed as complementary form-fitting profiles  4  and  5 . The opposite form-fitting profiles of a panel are of complementary design in each case. In this way, a further panel  3  can be attached to every previously laid panel  2 .  
         [0040]     Form-fitting profiles  4  and  5  are based on the prior art according to German utility model G 79 28 703 U1, particularly on the form-fitting profiles of the practical example. The form-fitting profiles according to the invention are developed in such a way that they permit the articulated and resilient connection of panels.  
         [0041]     One of the form-fitting profiles  4  of the present invention is provided with a joint projection  6  protruding from one narrow side. For the purpose of articulated connection, the lower side of joint projection  6 , which faces the base in laid condition, displays a cross-section with a convex curvature  7 . Convex curvature  7  is mounted in rotating fashion in complementary form-fitting profile  5 . In the practical example shown, convex curvature  7  is designed as a segment of a circle. Part  8  of the narrow side of panel  3 , which is located below joint projection  6  and faces the base in laid condition, stands farther back from the free end of joint projection  6  than part  9  of the narrow side, which is located above joint projection  6 . In the practical example shown, part  8  of the narrow side, located below joint projection  6 , recedes roughly twice as far from the free end of joint projection  6  and part  9  of the narrow side, located above joint projection  6 . The reason for this is that the segment of a circle of convex curvature  7  is of relatively broad design. As a result, the point of convex curvature  7  of joint projection  6  that projects farthest is positioned in such a way that it is located roughly below top edge  10  of panel  3 .  
         [0042]     Part  9  of the narrow side, located above joint projection  6 , protrudes from the narrow side on the top side of panel  3 , forming abutting joint surface  9   a.  Part  9  of the narrow side recedes between this abutting joint surface  9   a  and joint projection  6 . This ensures that part  9  of the narrow side always forms a closed, top-side joint with the complementary narrow side of the second panel  2 .  
         [0043]     The upper side of joint projection  6 , opposite convex curvature  7  of joint projection  6 , displays a short, straight section  11  that is likewise positioned parallel to substrate U in laid condition. From this short section  11  to the free end, the upper side of joint projection  6  displays a bevel  12  that extends up to the free end of joint projection  6 .  
         [0044]     Form-fitting profile  5  of a narrow side, which is complementary to form-fitting profile  4  described, displays a joint recess  20 . This is essentially bordered by a lower wall  21  that faces substrate U in laid condition, and an upper wall  22 . On the inside of joint recess  20 , lower wall  21  is provided with a concave curvature  23 . Concave curvature  23  is likewise designed in the form of a segment of a circle. In order for there to be sufficient space for the relatively broad concave curvature  23  on lower wall  21  of joint recess  20 , lower wall  21  projects farther from the narrow side of panel  2  than upper wall  22 . Concave curvature  23  forms an undercut at the free end of lower wall  21 . In finish-laid condition of two panels  2  and  3 , this undercut is engaged by joint projection  6  of associated form-fitting profile  4  of adjacent panel  3 . The degree of engagement, meaning the difference between the thickest point of the free end of the lower wall and the thickness of the lower wall at the lowest point of concave curvature  23 , is such that a good compromise is obtained between flexible resilience of two panels  2  and  3  and good retention to prevent form-fitting profiles  4  and  5  being pulled apart in the laying plane.  
         [0045]     In comparison, the fastening system of the prior art utility model G 79 28 703 U1 displays a considerably greater degree of undercut. This results in extraordinarily stiff points of connection, which cause high notch stresses when subjected to stress on an uneven substrate.  
         [0046]     According to the practical example, the inner side of upper wall  22  of joint recess  20  of panel  2  is positioned parallel to substrate U in laid condition.  
         [0047]     On lower wall  21  of joint recess  20  of panel  2 , which faces substrate U, the inner side of wall  21  has a bevel  24  that extends up the free end of lower wall  21 . As a result, the wall thickness of this wall becomes increasingly thin towards the free end. According to the practical example, bevel  24  follows on from the end of concave curvature  23 .  
         [0048]     Joint projection  6  of panel  3  and joint recess  20  of panel  2  form a common joint G, as illustrated in  FIG. 2 . When panels  2  and  3  are laid, the previously described bevel  12 , on the upper side of joint projection  6  of panel  3 , and bevel  24  of lower wall  21  of joint recess  20  of panel  2  create spaces for movement  13  and  25 , which allow joint G to rotate over a small angular range.  
         [0049]     In laid condition, short straight section  11  of the upper side of joint projection  6  of panel  3  is in contact with the inner side of upper wall  22  of joint recess  20  of panel  2 . Moreover, convex curvature  7  of joint projection  6  lies against concave curvature  23  of lower wall  21  of joint recess  20  of panel  2 .  
         [0050]     Lateral abutting joint surfaces  9   a  and  26  of two connected panels  2  and  3 , which face the upper side, are always definitely in contact. In practice, simultaneous exact positioning of convex curvature  7  of joint projection  6  of panel  3  against concave curvature  23  of joint recess  20  of panel  2  is impossible. Manufacturing tolerances would lead to a situation where either abutting joint surfaces  9   a  and  26  are positioned exactly against each other or joint projection  6 /recess  20  are positioned exactly against each other. In practice, the form fitting profiles are thus designed in such a way that abutting joint surfaces  9   a  and  26  are always exactly positioned against each other and joint projection  6 /recess  20  cannot be moved far enough in each other to achieve an exact fit. However, as the manufacturing tolerances are in the region of hundredths of a millimeter, joint projection  6 /recess  20  also fit almost exactly.  
         [0051]     Panels  2  and  3 , with complementary form-fitting profiles  4  and  5  described, can be fastened to each other in a variety of ways. According to  FIG. 3 , one panel  2  with a joint recess  20  has already been laid, while a second panel  3 , with a complementary joint projection  6 , is being inserted into joint recess  20  of first panel  2  at an angle in the direction of the arrow P. After this, second panel  3  is rotated about the common center of circle K of the segments of a circle of convex curvature  7  of joint projection  6  and concave curvature  23  of joint recess  20  until second panel  3  lies on substrate U.  
         [0052]     Another way of joining the previously described panels  2  and  3  is illustrated in  FIG. 4 , according to which first panel  2  with joint recess  20  has been laid and a second panel  3  with joint projection  6  is slid in the laying plane and perpendicular to form-fitting profiles  4  and  5  in the direction of the arrow P until walls  21  and  22  of joint recess  20  expand elastically to a small extent and convex curvature  7  of joint projection  6  has overcome the undercut at the front end of concave curvature  23  of the lower wall and the final laying position is reached.  
         [0053]     The latter way of joining is preferably used for the short narrow sides of a panel if these are provided with the same complementary form-fitting profiles  4  and  5  as the long narrow sides of the panels.  
         [0054]      FIG. 5  illustrates fastening system  1  in use. Panels  2  and  3  are laid on an uneven substrate U. A load has been applied to the upper side of first panel  2  with form-fitting profile  5 . The narrow side of panel  2  with form-fitting profile  5  has been lifted as a result. Form-fitting profile  4  of panel  3 , which is connected to form-fitting profile  5 , has also been lifted. Joint G results a bend between the two panels  2  and  3 . The spaces for movement  13  and  25  create room for the rotary movement of the joint. Joint G, formed by the two panels  2  and  3 , has been moved slightly upwards out of the laying plane. Space for movement  13  has been utilized to the full for rotation, meaning that the area of bevel  12  on the upper side of joint projection  6  of panel  3  is in contact with the inner side of wall  22  of panel  2 . The point of connection is inherently flexible and does not impose any unnecessary, material-fatiguing bending loads on the involved form-fitting profiles  4  and  5 .  
         [0055]     The damage soon occurring in form-fitting profiles according to the prior art, owing to the breaking of the joint projection or the walls of the form-fitting profiles, is avoided in this way.  
         [0056]     Another advantage results in the event of movement of the joint in accordance with  FIG. 5 . This can be seen in the fact that, upon relief of the load, the two panels drop back into the laying plane under their own weight. Slight elastic deformation of the walls of the joint recess is also present in this case. This elastic deformation supports the panels in dropping back into the laying plane. Only very slight elastic deformation occurs because the center of motion of the joint, which is defined by curvatures  7  and  23  with the form of a segment of a circle, is located within the cross-section of joint projection  6  of panel  3 .  
         [0057]      FIG. 6  illustrates movement of the joint of two laid panels  2  and  3  in the opposite sense of rotation. Panels  2  and  3 , laid on uneven substrate U, are bent downwards. The design is such that, in the event of downward bending of the point of connection out of the laying plane towards substrate U, far more pronounced elastic deformation of lower wall  21  of joint recess  20  occurs than during upward bending from the laying plane. This measure is necessary because downward-bent panels  2  and  3  cannot return to the laying plane as a result of their own weight when the load is relieved. However, the greater elastic deformation of lower wall  21  of joint recess  20  generates an elastic force that immediately moves panels  2  and  3  back into the laying plane in the manner of a spring when the load is relieved.  
         [0058]     In the present form, the previously described form-fitting profiles  4  and  5  are integrally molded on the narrow sides of panels  2  and  3 . This is preferably achieved by means of a so-called formatting operation, where a number of milling tools connected in series mills the shape of form-fitting profiles  4  and  5  into the narrow sides of panels  2  and  3 . Panels  2  and  3  of the practical example described essentially consist of MDF board with a thickness of 8 mm. The MDF board has a wear-resistant and decorative coating on the upper side. A so-called counteracting layer is applied to the lower side in order to compensate for the internal stresses caused by the coating on the upper side.  
         [0059]     Finally,  FIG. 7  shows two panels  2  and  3  in laid condition, where fastening system  1  is used with a filler  30  that remains flexible after curing. Filler  30  is provided between all adjacent parts of the positively connected narrow sides. In particular, the top-side joint  31  is sealed with the filler to prevent the ingress of any moisture or dirt. In addition, the elasticity of filler  30 , which is itself deformed when two panels  2  and  3  are bent, brings about the return of panels  2  and  3  to the laying plane.  
         [0060]      FIG. 8  shows a perspective representation of the laying of a floor, where the method for laying and interlocking panels according to the invention is used. For the sake of the simplicity of the drawing, the details of the retaining profiles have been omitted. However, these correspond to the form-fitting profiles in FIGS.  1  to  7  and display profiled joint projections and complementary joint recesses that extend over the entire length of the narrow sides.  
         [0061]     A first row R 1 , comprising rectangular, plate-like panels  40 ,  41 ,  42  and  43 , can be seen. Panels  40 ,  41 ,  42  and  43  of first row R 1  are preferably laid in such a way that joint recesses are always located on the free sides of a laid panel and new panels can be attached by their joint projections to the joint recesses of the laid panels.  
         [0062]     Panels  40 ,  41 ,  42  and  43  of fist row R 1  have been interlocked at their short sides. This can be done either in the laying plane by sliding the panels laterally into each other in the longitudinal direction of the retaining profiles of the short narrow sides or, alternatively, by joining the retaining profiles while positioning a new panel at an angle relative to a laid panel and subsequently pivoting the new panel into the laying plane. The laying plane is indicated by broken line V in  FIGS. 8 and 9 . The retaining profiles have been interlocked without any major deformation in both cases. The panels are interlocked in the direction perpendicular to the laying plane. Moreover, they are also interlocked in the direction perpendicular to the plane of the narrow sides.  
         [0063]     Panels  44 ,  45  and  46  are located in a second row R 2 . First, the long side of panel  44  was interlocked by inserting its joint projection by positioning it at an angle relative to the panels of first row R 1  and subsequently pivoting panel  44  into the laying plane.  
         [0064]     In order to lay a new panel in the second row, several alternative procedural steps can be performed, two alternatives of which are described on the basis of  FIGS. 8 and 9 . A further alternative is explained without an illustration.  
         [0065]     When laying a new panel  46  in the second row, one of its long sides has to be interlocked with first row R 1  and one of its short sides with laid panel  45 . A short side of new panel  46  is always first interlocked with laid panel  45 .  
         [0066]     According to  FIG. 8 , free end  45   a  is pivoted upwards out of the laying plane through a pivoting angle α about interlocked long narrow side  45   b.  Panel  45  is twisted in such a way during the process that the dimension of pivoting angle α decreases from free end  45   a  towards interlocked end  45   c.  According to  FIG. 8 , interlocked end  45   c  remains in place in the laying plane. In this position, new panel  46  is set at an angle relative to panel  45  on free end  45   a  of the latter. Panel  46  can initially not be set against the whole length of the short side, because panel  45  is already interlocked with panels  41  and  42  of the first row. Panel  46  is now pivoted in the direction of arrow A until it is likewise positioned at pivoting angle a relative to the laying plane, as indicated by dotted pivoting position  46 ′. In pivoting position  46 ′, panel  46  is slid in the direction of arrow B and the joint projection of panel  46  is inserted into the joint recess of panels  42  and  43  of first row R 1 . In this context, the short narrow side of panel  46  is simultaneously slid completely onto short narrow side  45   a  of panel  45 . Finally, panels  45  and  46  are jointly pivoted into the laying plane in the direction of arrow C and interlocked with the panels of first row R 1 .  
         [0067]     Damage to the retaining profiles due to a high degree of deformation during laying and interlocking is avoided.  
         [0068]     The alternative laying method according to  FIG. 9  likewise provides for free end  45   a  to be pivoted upwards out of the laying plane by a pivoting angle α about interlocked long narrow side  45   b,  where panel  45  is twisted and its free end  45   a  is inclined through a pivoting angle α relative to the laying plane. Interlocked end  45   c  again remains in place in the laying plane. In contrast to  FIG. 8 , panel  46  is now likewise positioned at the pivoting angle α relative to the laying plane and its short side  46   a  is slid in the longitudinal direction onto the retaining profile of short side  45   a  of panel  45 . In this inclined position, the joint projection of long side  46   b  of panel  46  is immediately inserted into the joint recess of panels  42  and  43  of first row R 1 . Finally, panels  45  and  46  are jointly pivoted into the laying plane and interlocked with the panels of first row R 1 .  
         [0069]     The alternatives not shown for laying and interlocking panels consist in first interlocking the short narrow ends of panels  45  and  46  in the laying plane. The alternatives described here can be followed by examining  FIGS. 8 and 9 , which is why reference numbers are also given for the alternatives not illustrated.  
         [0070]     According to one of the alternatives, the retaining profiles of short narrow sides  45   a  and  46   a  of panels  45  and  46  are slid into each other in the longitudinal direction while both panels  45  and  46  remain in place in the laying plane. According to another alternative, panel  45  lies in the laying plane and panel  46  is set at an angle against short narrow side  45   a  of panel  45  and then pivoted into the laying plane.  
         [0071]     According to the above alternative procedural steps for interlocking panels  45  in the laying plane, the long side of panel  46  is not yet interlocked with panels  42  and  43  of first row R 1 . To this end, panel  46  and end  45   a  of panel  45  must be lifted into the previously described inclined position at pivoting angle α. The joint projection of long side  46   b  of panel  46  is then inserted into the joint recess of panels  42  and  43  of first row R 1 , and panels  45  and  46  are finally jointly interlocked with panels  42  and  43  of first row R 1  by being pivoted into laying plane V.  
         [0072]     Although certain presently preferred embodiments of the disclosed invention have been specifically described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the various embodiments shown and described herein may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention be limited only to the extent required by the appended claims and the applicable rules of law.