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BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The invention relates to a molded brick, in particular made from concrete, for laying ground coverings, the molded brick having an upper side which is delimited in the transition to upright side faces by a side edge which frames the upper side. Furthermore, the invention relates to a ground covering comprising molded bricks of this type. 
         [0003]    2. Prior Art 
         [0004]    Molded bricks for ground coverings are known from practice in different designs. For example, there are molded bricks with rectilinearly extending side edges, or molded bricks which are reminiscent of natural stones with regard to the design and have irregularly shaped side edges and side faces. 
         [0005]    Proceeding from this, the invention is based on the object of developing molded bricks of the type mentioned in the introduction, in particular with regard to a harmonious course of the side edge. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    In order to achieve this object, a molded brick which is designed according to the invention is a molded brick, in particular made from concrete, for laying ground coverings, the molded brick having an upper side which is delimited in the transition to upright side faces by a side edge which frames the upper side, characterized in that the course of the side edge is of curved configuration at least in regions and corresponds to a mathematical function. According to this, there is provision for the course of the side edge to be of curved configuration at least in regions and to correspond to a mathematical function. 
         [0007]    It has been shown that the use of a mathematical function for fixing the course of the side edge leads overall to an improved appearance of the molded brick in comparison with conventional methods. 
         [0008]    There is provision in one preferred development of the invention for the profile of the side edge to correspond at least in regions to the function ƒ(x)=a*ln(x)+b. The use of a function on the basis of the logarithm surprisingly results in a particularly harmonious appearance. 
         [0009]    A further special feature can consist in that the course of curved regions of the side edge is different, in particular in the case of the use of the above function by using different values for the variables a and b for different regions. In other words, it is proposed not to select the same function for all regions of the side edge, but on the other hand also not to use completely different functions, but rather only to use parameters for always adapting basically the same function. 
         [0010]    According to one preferred development of the invention, the course of the side edge is not stipulated continuously by the mathematical function, but rather the regions of the side edge which are curved according to the mathematical function are connected to circular extending regions. This leads to an appealing exterior of the molded brick. 
         [0011]    A preferably independent achievement of the object can consist in the course of the side edge having concavely and convexly curved regions. In this way, special optical effects can be achieved when laying molded bricks of this type to form a ground covering, such as the impression that the molded bricks appear to have an arched upper side, although the upper side is actually substantially flat. 
         [0012]    There is preferably provision in this context for the side edge to have a bulge in the region of a longitudinal side of the molded brick, such that two concavely curved regions of the side edge enclose a convexly curved region of the side edge. 
         [0013]    It is particularly advantageous if the upright side faces are not of curved configuration, but rather extend substantially in a continuous plane and in an upright manner until shortly before the region of the upper side, the transition between the planar side faces and the curved side edges being compensated for by transition faces, in particular in the region of a circumferential bevel. In this way, the molded bricks can namely be laid particularly easily. In addition, it is simply possible in this way to integrally form spacers on the side faces which are otherwise planar. 
         [0014]    Furthermore, protection is claimed for a ground covering comprising the molded bricks according to the invention. 
         [0015]    A further special feature consists in the adaptation of the molded bricks for carrying horizontal loads. 
         [0016]    Further details result from the subclaims and otherwise from the description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    In the following text, one preferred exemplary embodiment of the invention will be explained using the drawing, in which: 
           [0018]      FIG. 1  shows a first molded brick according to the invention in a plan view, 
           [0019]      FIG. 2  shows the molded brick according to  FIG. 1  in a view from below, 
           [0020]      FIG. 3  shows the molded brick according to  FIG. 1  in a view of a short side face, 
           [0021]      FIG. 4  shows the molded brick according to  FIG. 1  in a view of a long side face, 
           [0022]      FIG. 5  to  FIG. 8  show isometric representations of the molded brick according to  FIG. 1 , 
           [0023]      FIG. 9  shows a diagrammatic plan view of the molded brick according to  FIG. 1  with a representation of the construction of the side edges, 
           [0024]      FIG. 10  to  FIG. 17  show a second molded brick according to the invention in an analogous representation to  FIG. 1  to  FIG. 8 , 
           [0025]      FIG. 18  to  FIG. 21  show a ground covering comprising molded bricks according to  FIGS. 1 to 17  in a plan view and in a three-dimensional representation, 
           [0026]      FIG. 22  shows a further molded brick according to the invention in a plan view, 
           [0027]      FIG. 23  to  FIG. 27  show the molded brick according to  FIG. 22  in further views and isometric representations, 
           [0028]      FIG. 28  to  FIG. 33  show a further molded brick according to the invention in an analogous representation to  FIGS. 22 to 27 , 
           [0029]      FIG. 34  to  FIG. 39  show a further molded brick according to the invention in an analogous representation to  FIGS. 22 to 27 , and 
           [0030]      FIG. 40  to  FIG. 43  show a ground covering comprising molded bricks according to  FIGS. 22 to 33  in a plan view and three-dimensional representations. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0031]    First of all, the exemplary embodiment according to  FIGS. 1 to 21  will be described. After this, the exemplary embodiment according to  FIGS. 22 to 43  will be described, only the differences from the first exemplary embodiment being concentrated on there. Here, consistent designations are used for identical parts. 
         [0032]    The first exemplary embodiment is concerned with the production of a ground covering  10  from two different types of molded bricks  11 ,  12  which, combined with one another, are laid to form the ground covering  10 . A first type of molded brick  11  is shown in figs  FIGS. 1 to 9 , and the second type of molded brick  12  results from  FIGS. 10 to 17 . 
         [0033]    The molded bricks  11 ,  12  in each case have a planar upper side  13 , a corresponding lower side  14  and four upright side faces, namely longer longitudinal side faces  15 ,  16  and shorter transverse side faces  17 ,  18 . While the transverse side faces  17 ,  18  have a continuous rectilinear course, the longitudinal side faces  15 ,  16  are of angled away or kinked configuration, with the result that the molded bricks  11 ,  12  have an elongate hexagonal design in outline, the longitudinal side faces  15 ,  16  being angled away in the region of the longitudinal center. 
         [0034]    A further feature is spacers  19  which are arranged on the side faces  15 ,  16 ,  17 ,  18  and, starting from the lower side  14 , extend until shortly before the upper side  13  of the molded bricks  11 ,  12 . The spacers are integrally formed on the side faces  15 ,  16 ,  17 ,  18  in pairs as elongate web-like structures with a beveled upper side. Depending on the intended use, the spacers  19  can also be dispensed with, or the spacers  19  can have a different design and/or arrangement. 
         [0035]    One special feature of the molded bricks  11 ,  12  lies in the design of side edges  20  which extend circumferentially in the region of the upper side  13  of the molded bricks  11 ,  12 . In the present case, the side edge  20  of the upper side  13  is understood as being the transition from the upper side  13  to the upright side faces  15 ,  16 ,  17 ,  18 . In the present case, the special feature consists in the circumferential side edge  20  being of curved configuration in outline. To this end, reference is made to  FIG. 9 . The individual sections of the side edge  20  are shown diagrammatically there, with in each case regions of different curvature. Furthermore, it can be seen that the molded brick  11  has an axis of symmetry  21  which extends transversely through the two longitudinal side faces  15 ,  16 , namely in the longitudinal center of the latter. 
         [0036]    The following regions result with reference to  FIG. 9 :
   1. A region  22  extends along the left-hand half of the longitudinal side face  15  as far as via the corner into the region of the transverse side face  18 .   2. A region  22 ′ results from mirroring the region  22  at the axis of symmetry  21 .   3. A region  23  lies between the two regions  22  and  22 ′.   4. A region  24  adjoins the region  22  in the region of the transverse side faces  18 .   5. A region  24 ′ lies, mirrored via the axis of symmetry  21 , on the opposite transverse side face  17 .   6. A region  25  adjoins the region  24  and extends in the region of the corner between the transverse side face  18  and the longitudinal side face  16 .   7. A region  25 ′ results once again by mirroring of the region  25  at the axis of symmetry  21 .   8. In a similar manner to the region  22  along the longitudinal side face  15 , a region  26  extends along the longitudinal side face  16 , however.   9. A region  26 ′ corresponds to the region  26  mirrored at the axis of symmetry  21 .   10. A region  27  is situated between the two regions  26  and  26 ′ in the region of the axis of symmetry.   
 
         [0047]    The course of the side edge  20  in the regions  22 ,  23 ,  24 ,  25 ,  26 ,  27  results as follows: 
         [0000]    1. Regions  22  and  22 ′: ƒ(x)=3*ln(x)−19.5
 
2. Region  23 : constant radius r=56
 
3. Region  24 : constant radius r=1.322
 
4. Regions  25  and  25 ′: ƒ(x)=ln(x)−137.5
 
5. Regions  26  and  26 ′: ƒ(x)=3*ln(x)−19.5
 
6. Region  27 : constant radius r=28.3
 
         [0048]    The special feature of the molded brick  11  consists in the course of the side edge  20  therefore corresponding in the regions  22 ,  22 ′,  25 ,  25 ′ and  26 ,  26 ′ to a mathematical function, namely on the basis of the logarithm. The regions which are curved in this way are connected to one another by constantly curved regions  23 ,  24 ,  24 ′ and  27 . 
         [0049]    In this way, the result is a particularly harmonic course of the side edge  20 . It goes without saying that the formula for the logarithmically curved regions can be varied according to the example: 
         [0000]      ƒ( x )= a *ln( x )+ b  
 
         [0050]    Different values can be used for the variables a and b. Furthermore, the regions can be displaced by transformation. 
         [0051]    A further special feature consists in the regions  26  and  26 ′ of the side edge  20  being concavely arched, namely in relation to the center point of the upper side  13 , whereas the remaining regions  22 ,  22 ′,  23 ,  24 ,  24 ′,  25 ,  25 ′ and  27  are of convexly arched configuration. 
         [0052]    The molded brick  12  according to  FIGS. 10 to 17  differs from the molded brick  11  merely in that the regions  24  and  24 ′ are of concavely arched configuration in the region of the transverse side faces  17 ,  18 , and not of convexly arched configuration as in the first exemplary embodiment. 
         [0053]    A common feature of both molded bricks  11 ,  12  is that the upright side faces  15 ,  16 ,  17 ,  18  are not of arched configuration, but rather are of rectilinear configuration. This results in a different course of the upright side faces in comparison with the side edge  20 . This difference is compensated for by what are known as transition faces  28 . 
         [0054]    It can be seen from  FIGS. 18 to 21  that the molded bricks  11  and  12  are laid together to form a common ground covering  10 . Here, the molded bricks  11 ,  12  are laid in rows  29 , the molded bricks  11 ,  12  being laid alternately within a row  29 . 
         [0055]    In addition, the rows  29  are arranged offset with respect to one another by half a brick length, in what is known as the half brick lattice. This manner of laying results in the following special features: the molded bricks  11 ,  12  lie so close to one another that, in the region of the transverse side faces  17 ,  18 , a molded brick  11  with a convexly arched transverse side face  17  lies next to a molded brick  12  with a concavely arched transverse side face  18 . A convex bulge  34 , formed by the region  27 , on the side edge  20  comes to lie between two transverse side faces  17 ,  18  of molded bricks  11 ,  12  of an adjacent row  29 . The course of the joints between the molded bricks  11 ,  12  accordingly follows the course of the side edges  20 . 
         [0056]    The ground covering  10  has an interesting optical effect as a result of this type of laying. The impression is namely produced that the molded bricks  11 ,  12  have an arched upper side  13 , which is actually not the case. The representation according to  FIG. 20  shows this optical effect clearly. 
         [0057]    A further advantage results from the longitudinal side faces  15 ,  16  of angled away configuration. Within the ground covering  10 , the two “halves” of the longitudinal side faces  15 ,  16  bear against correspondingly angled away regions of longitudinal side faces  15 ,  16  of adjacent molded bricks  11 ,  12 . In this way, horizontal forces which act transversely with respect to the rows  29  are transmitted uniformly from a molded brick  11 ,  12  to two adjacent molded bricks  11 ,  12  of an adjacent row  29 , without the otherwise usual tilting of the molded bricks  11 ,  12  and the associated edge pressures occurring. 
         [0058]      FIGS. 22 to 43  show a second exemplary embodiment of the invention. In said figures, a ground covering  30  is produced from three different molded bricks  31 ,  32 ,  33 . Molded brick  30  is shown in  FIGS. 22 to 27 . Molded brick  32  results from  FIGS. 33 to 38 , and molded brick  33  results from  FIGS. 28 to 32 . 
         [0059]    The molded brick  31  shown in  FIGS. 22 to 27  corresponds substantially to the molded brick  12  shown in  FIGS. 10 to 17 , but with shorter longitudinal side faces  15 ,  16 . By way of example, a version is also shown without spacers on the upright side faces  15 ,  16 ,  17 ,  18 . 
         [0060]    The molded brick  32  shown in  FIGS. 34 to 39  corresponds substantially to the molded brick  11  shown in  FIGS. 1 to 9 , but the angled away portion of the longitudinal side face  16  is not situated in the longitudinal center of the molded brick  32 , but rather offset laterally with respect thereto. The molded brick  33  shown in  FIGS. 28 to 32  is configured in accordance with the molded brick  32 , but with a mirrored position of the angled away portion. 
         [0061]    Within the laid ground covering  30 , in each case two different types of molded bricks  31 ,  32  or  31 ,  33  are laid within a row  29 , to be precise alternately as in the first exemplary embodiment. This therefore results in a corresponding laying pattern as in the first exemplary embodiment, but with a different optical impression. 
         [0062]    It goes without saying that the ground coverings can also be configured with a greater number of different molded brick types. 
       LIST OF DESIGNATIONS 
       [0000]    
       
           10  Ground covering 
           11  Molded brick 
           12  Molded brick 
           13  Upper side 
           14  Lower side 
           15  Longitudinal side face 
           16  Longitudinal side face 
           17  Transverse side face 
           18  Transverse side face 
           19  Spacer 
           20  Side edge 
           21  Axis of symmetry 
           22  Region 
           22 ′ Region 
           23  Region 
           24  Region 
           24 ′ Region 
           25  Region 
           25 ′ Region 
           26  Region 
           26 ′ Region 
           27  Region 
           28  Transition face 
           29  Row 
           30  Ground covering 
           31  Molded brick 
           32  Molded brick 
           33  Molded brick 
           34  Bulge

Summary:
A molded brick, in particular made from concrete, for laying ground coverings ( 10, 30 ), the molded brick ( 11, 12, 31, 32, 33 ) having an upper side ( 13 ) which is delimited in the transition to upright side faces ( 15, 16, 17, 18 ) by a side edge ( 20 ) which frames the upper side ( 13 ). The course of the side edge ( 20 ) of the molded brick is of curved configuration at least in regions and to correspond to a mathematical function, the course of the side edge ( 20 ) preferably corresponding at least in regions to the function ƒ(x)=a*ln(x)+b.