Patent Publication Number: US-8529386-B2

Title: Ball

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an inflatable ball, in particular a soccer ball, having a shell comprising a plurality of panels. 
     2. Background Art 
     Soccer balls, as well as other inflatable balls, are typically produced as follows. In a first step an inner bladder, which can be made from latex, is reinforced with a carcass, or by a nylon thread wound around the bladder. An outer shell is then arranged on the carcass or on the nylon winding. 
     For simple balls the shell can be integrally formed of plastic material, or two preformed half shells of the ball shell are connected to each other, for example by gluing or sealing, as it is disclosed in FIG. 5 of the U.S. Pub. No. 2009/0011878. The present invention is related to higher quality balls. The shell of high quality balls is composed of a multitude of prefabricated panels. To clearly distinguish these two fundamentally different constructions of a ball shell (i.e., a shell formed from two half shells and a shell formed from a multitude of prefabricated panels), in the following the term panel is taken to mean a separately prefabricated portion which forms less than a half of the ball shell. 
     The panels must be suitably attached relative to each other, for example by sewing the edges of the panels together or also by gluing the panels to the surface of the carcass. A direct gluing or (laser) welding of the edges of the panels to each other is also conceivable. For the sake of simplicity, the region in which two adjacent panels contact each ether, is simply called a “seam” in the following description, regardless of whether the panels are actually sewn to each other in a standard manner or whether they are fixed relative to each other in any other way in order to provide the outer shell of the ball. 
     In the past, the shell of soccer balls typically consisted of 32 pentagonal and/or hexagonal panels. However, more recent ball designs have a lower number of larger-sized panels. The new designs improve the ball control by the player, since each seam creates an inhomogenity, typically a localized stiffness, in the outer shell so that the ball reacts differently when kicked with a shoe in the centre of a panel than when being kicked in the seam area. Unavoidable production tolerances during the manufacture of the seam result in an oven greater inhomogeneity and are another reason why the player cannot perfectly control the ball and that a shot ball does not follow a precise flight path. Furthermore, the arrangement of many seams leads to deviations from perfect sphericity. 
     Using larger panels reduces these problems, since less seams are needed for the manufacture of the overall shell of a ball having the same size. In addition, the manufacturing costs are reduced for larger panels, since less effort is needed to interconnect the panels and/or to arrange them on the carcass. Also the production tolerances are lower since there are less possibilities to create faulty seams during production. This applies for the frequency of occurrence as well as for the extent of such production tolerances. 
     However, balls having large panels can have negative flight properties and can, for example, tend to have instability. As a result of aerodynamic effects, there can be unintended and unpredictable flutter movements of the ball. It is immediately apparent that these aerodynamic effects substantially impair a controlled play and precise shots. Similar problems also occur for inflatable balls for others sports, such as handball and volleyball. 
     For improving the aerodynamic properties, it is known from the U.S. Pat. No. 4,318,544 to provide a soccer ball with seven parallel grooves extending in a uniform pentagonal arrangement over the complete shell of the ball. The arrangement is such that there are no grooves on certain panels of the shell of the ball, whereas up to three groups of seven parallel grooves contact each other on other panels. 
     While this arrangement may improve the flight properties of the ball, it does not improve precision during play. The extremely different surface design of the panels leads to a very different behavior of the ball when contacting a shoe of a player. Both, during dribbling, but also for an aimed shot, the ball will behave differently depending on whether the shoe of the player hits a panel provided with the seven parallel grooves or a standard panel without any ridges. 
     Embodiments of the present invention are, therefore, based on the problem to provide a ball, in particular a soccer ball, having good properties both, when contacting the shoe of the player but also in the air, and therefore allows more precise play. 
     BRIEF SUMMARY OF THE INVENTION 
     In one embodiment, the ball may comprise an outer shell having a plurality of panels, wherein the panels are interconnected by seams. Each panel may comprise at least one pseudo-seam, which extends at least over a part of an outer surface of the panel. 
     As a result of the pseudo-seams of the invention and their distribution on each panel, the panels of the ball of the invention can be made larger so that the number and the lengths of the seams of the outer shell are reduced. In contrast to real seams, the pseudo-seams have no practical influence on the deformation properties and the contact properties of the panels. However, they have approximately the same aerodynamic effect as real seams and thereby avoid the unintended flutter movements in the flight path. This applies in particular, if the pseudo-seams have a cross section corresponding essentially to the cross section of a seam between two panels, for example an essentially V- or U-shaped cross section having a width in a range from about 1 mm to about 3 mm, for example about 2 mm, and a depth in a range from about 0.5 mm to about 2 mm, for example about 1 mm. 
     The term “substantially” means in this context, as well as generally within the present description, an accuracy within the limits of production tolerances. 
     In contrast to the prior art according to the above explained U.S. Pat. No. 4,318,544, each panel may comprise at least one pseudo-seam so that the effect on the aerodynamic properties is evenly distributed over all panels and thereby the complete outer shell. This may lead to improved flight properties. Also the local modification of the deformation properties and the contact properties by the pseudo-seam, which are only minor, is evenly distributed on each panel. As a result, a ball is provided which can be perfectly controlled on the shoe and in the air and allows very precise play. 
     Apart from the more homogeneous deformation and contact properties and the better flight properties, the ball of the invention can also be more cost-efficiently produced since the outer shell is assembled from a lower number of larger panels. Gluing, sewing or any other method to interconnect the panels therefore requires less process steps and working time and can be performed with lower production tolerances. 
     In some embodiments, the pseudo-seams may extend over the outer surface such that each panel is divided into at least two sub-panels. From an aerodynamic point of view, the ball therefore appears as if it was made of a plurality of small panels and enables precise flight paths without any flutter movements. 
     In some embodiments, in order to achieve an even distribution over the outer surface, the pseudo-seams may be arranged so that they are not parallel on the outer surface of a panel. On the contrary, in some embodiments, each pseudo-seam may either substantially interconnect two seams, or may form a closed curve on the outer surface of the panel. Other embodiments, are however, also conceivable in which each panel may be divided into four sub-panels by three arcuated pseudo-seams and/or modifications in which one or several additional pseudo-seams are foreseen which may extend parallel to an edge of a sub-panel over at least a part of its surface. 
     As already mentioned, the outer shell of the ball of the invention can be manufactured from a lower number of panels. In some embodiments, the outer shell may comprise twelve or less panels. In other embodiments, the outer shell may comprise eight panels or less. As a result, a ball may be provided having substantially more homogeneous deformation and contact properties so that it can be precisely controlled by the shoe of the player. 
     In some embodiments, the outer shell may comprise a first and a second group of panels, each panel of the first group having the shape of a rounded triangle with convex edges and each panel of the second group having six corners with alternating concave and essentially straight edges. The convex edge of a panel of the first group can form a seam with the concave edge of a panel of the second group. Comprehensive tests have revealed that this panel form and the seam distribution resulting out of it are especially beneficial for the play properties of the ball. 
     In order to avoid excessive tensions in the shell, in some embodiments, the panels may comprise a three-dimensionally domed shape prior to interconnecting them to form the outer shell. This can be achieved by suitable manufacturing methods of the materials used for the panels, such as deep-drawing using a domed mold. Injection molding of the panels is however also conceivable to manufacture complex designs with little effort. 
     In addition to the pseudo-seams, which serve for improving the aerodynamic properties, in some embodiments, each panel may further comprise a surface texture having a height of ≦ about 0.5 mm, for example ≦ about 0.05 mm. These surface textures or corrugations may be substantially smaller than the pseudo-seams and are therefore of less relevance for the aerodynamic properties of the ball. However, they improve the grip of the ball, in particular when wet, and therefore, facilitate ball control and catching or halting of the ball by the goal keeper. 
     In some embodiments, each panel may comprise at least one backing material and at least one surface material, wherein the pseudo-seam may be provided in both the backing material and the surface material. 
     In some embodiments, the backing material may comprise a foamed material and the surface material may comprise at least one thermoplastic polyurethane (TPU) film. Other materials can also be used for the plastic films, as for example polyurethane (PU), polyamide (PA), or polyvinyl chloride (PVC). The pseudo-seams and/or the surface texture can be created in many different ways, such as master forming of the surface material and/or the backing material, for example by (multi-component) injection molding, vacuum-forming, deep-drawing and/or laser etching of the TPU film and/or the backing material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
       In the following, aspects of the present invention are described in more detail with reference to the accompanying figures. These figures show: 
         FIG. 1  is a schematic presentation of the flutter movement of a ball due to aerodynamic effects in top view; 
         FIGS. 2   a, b  are presentations of a presently preferred embodiment of a ball according to the present invention; 
         FIG. 3  is a detailed presentation of a panel of a first group of panels in the embodiment of  FIGS. 2   a, b;    
         FIG. 4  is a detailed presentation of a panel of the second group of panels in the embodiment of  FIGS. 2   a, b;    
         FIG. 5  is a two-dimensional presentation of all of the panels of the embodiments of  FIGS. 2   a, b;    
         FIG. 6  is a schematic presentation of a seam between two panels; 
         FIG. 7  is a schematic presentation of a pseudo-seam; 
         FIG. 8  is a diagram for comparing flutter movements of balls with different geometries and qualities of the seams; 
         FIG. 9  is a schematic representation of an embodiment of a ball with pseudo-seams. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following, preferred embodiments and modifications of the present invention are described with reference to a soccer ball. However, it is to be understood that the present invention is not limited to soccer balls. On the contrary, also other inflatable balls, such as handballs, basketballs, volleyballs, balls for American Football etc. may comprise the features of the present invention. 
       FIG. 1  illustrates the basic problem of a flutter movement of a ball. Without aerodynamic effects, the flight path of the ball  1  would follow a straight trajectory  2  into the right corner of the goal  10 . However, due to aerodynamic effects, it may under certain conditions occur that lateral forces are exerted on the ball. The direction of these lateral forces can change over the flight path so that the ball  1  moves along the curved trajectory  3 . It is apparent that such a flight behavior impairs precise play. 
     Extensive experimental tests in a wind tunnel have shown that the probability of flutter movements occurring depends on a number of parameters. An important parameter is, how “smooth” the surface of the ball is. Balls having an outer shell made from a plurality of small panels, such as the ball shown in  FIG. 1 , which consists of 32 pentagons and/or hexagons, have generally a lower tendency to flutter movements than balls having an outer shell consisting of a lower number of larger panels. The high number of seams on the surface of a known ball avoids the asymmetric separation of turbulences and thereby the flutter movement of the ball. Apparently, it is decisive how many seams are met by the air flow around the ball. 
     However, it was already mentioned in the introductory part that the arrangement of the plurality of seams causes other difficulties, such as inhomogeneous deformation properties and contact properties of the ball over its outer shell, high manufacturing costs and large production tolerances. The latter can also negatively affect the good flight properties of such a ball. If not all of the seams are perfect, this may cause substantial deviations from a straight flight path. 
       FIGS. 2   a  and  2   b  present an embodiment of a ball  20  according to the present invention, which overcomes these difficulties but also allows a flight path without a noticeable flutter movement. The presented ball  20  comprises two groups of panels, a first group of panels  30  and a second group of panels  40 , which are individually shown in  FIGS. 3 and 4 . Panels  30  of the first group have a substantially rounded triangular shape, wherein not only the corners of the triangle are rounded but wherein also the three side edges are provided with a convex curvature. Panels  40  of the second group have six corners, which are connected via alternating concave and substantially straight edges. 
     Where the edges of the panels  30 ,  40  contact each other, the ball  20  comprises seams  50 . These seams  50  can be provided in many different ways. In the presented embodiment, the panels  30 ,  40  are glued to a carcass (not shown). At the same time, also the lateral edges of the panels  30 ,  40  are glued to each other so that the seams  50  are provided as bond seams. However, it is also conceivable to interconnect the panels  30 ,  40  in other ways along the seams  50 , such as by sewing, by welding of a suitable plastic material, or the like. Another option is to glue the panels  30 ,  40  only to the carcass without any bond or other direct interconnection between contacting panels  30 ,  40 . In this case, the seams  50  are exclusively defined by the contact area or the transition region between two adjacent panels  30 ,  40 . 
     The deterioration of the flight properties as a result of the use of a lower number of larger panels can be avoided if pseudo-seams  60  are arranged on the surface of the panels  30 ,  40 . As shown in  FIGS. 6 and 7  and described in more detail below, the pseudo-seams  60  on the surface of the panels  30 ,  40  have essentially the same cross section as the above described seams  50 . As a result, the ball  20  obtains aerodynamic properties corresponding to a ball having a substantially higher number of panels. In particular, the above described flutter movement of the ball is to a large extent avoided. 
     As can be seen in  FIGS. 2   a  and  2   b , in some embodiments, three pseudo-seams  60  may extend in an arcuate manner over the surface of the panel  40 . The panel  40  is thus divided into four sub-panels having essentially the same size. The pseudo-seams  60  extend separately from each other and are not parallel on at least a part of the surface of the panel  40 . Further, they meet the seams  50  in an essentially orthogonal arrangement, however, without intersecting the seams  50 . In another embodiment, it is however also possible that the pseudo-seams  60  actually intersect the seams. 
     In some embodiments, the surface of the panels  30  of the other group may also have a pseudo-seam  60 . This pseudo-seam  60  forms a closed curve and may extend essentially parallel to the seam  50 , which limits the panel  30 . Also the panel  30  may be divided by the arrangement of the pseudo-seam  60  into two sub-panels. In some embodiments, these sub-panels have approximately the same size. 
       FIGS. 3 and 4  show detailed presentations of the panels  30  ( FIG. 3) and 40  ( FIG. 4 ), respectively. Apart from the already explained pseudo-seams  60 , the Figures show that the individual panels  30 ,  40  of the ball  20  have preferably a domed, three-dimensional shape after their manufacture, but before being glued or otherwise joined together. In contrast to the panels of a standard soccer ball made from 32 pentagons and/or hexagons, which are typically punched out of a flat shell material, such as (artificial) leather, and which are brought into a three-dimensional shape only on the carcass/bladder of the ball, the panels  30 ,  40  are provided with the shape shown in  FIGS. 3 and 4  already prior to being attached to the ball  20 . As a result, excessive tensions in the panels  30 ,  40  after assembly to the outer shell may be avoided, which could negatively affect the deformation properties of the ball  20 . This is particularly important for a ball  20  having very large panels. However, the described domed shape is also preferable for smaller panels. An exemplary manufacturing method for domed, three-dimensional panels is disclosed in EP 1 424 105 A1, which has been submitted by applicant together with the company Molten Corporation, which is hereby incorporated in its entirety. 
       FIGS. 3 and 4  show in addition the preferred shape of the edges of the two panels  30 ,  40 . The panel  30  may have convex edges  31 , which form after attachment to the carcass of a ball  20  (not shown) a seam  50  together with corresponding concave edges  41  of the panels  40 . The long, slightly curved seam  50  fits particularly well to the spherical shape of the final ball  20  (cf.  FIGS. 2   a , and  b ) and thus may avoid tensions and the creation of stiff areas along the seam  50 .  FIG. 4  also shows the essentially straight edges  42 , which alternate with the concave edges  41 . 
       FIG. 5  shows a schematic presentation of some embodiments of panel shapes  30 ,  40  and their relative arrangement after “unfolding” of the outer shell of the ball  20 . It can be seen, that in this embodiment, the overall outer shell may be made from only eight panels  30 ,  40 , four of which have the shape of the above explained panels  30  and four of which have the shape of the above explained panels  40 . It is apparent that the effort, but also the manufacturing tolerances of the seams, may be substantially lower for such a small number of panels than in the case of the standard 32 pentagons and/or hexagons. However, neither the above described panel shapes, nor the use of exactly eight panels is essential for the present invention. Other panel shapes and numbers, for example twelve panels, can also lead to advantageous ball properties. In other embodiments, six uniform panels may be used. 
       FIG. 5  shows in addition once more the pseudo-seams  60  extending on the panels  30  and  40 . In particular, the closed curve of the pseudo-seam  60  on the panels  30  can be seen, which may extend essentially parallel to the edge of the panel  30 . Also, the three individual pseudo-seams  60  on the panels  40  can be seen extending substantially orthogonal starting from the edge of a panel  40  in an arcuate manner over its surface and thereby dividing the panel  40  into four sub-panels. Tests in a wind tunnel have shown that the panel shapes  30 ,  40  and the distribution of the pseudo-seams of  FIG. 5  lead to particular advantageous flight properties of the ball, showing the lowest amount of flutter movements. 
       FIG. 9  represents a further embodiment. Instead of pseudo-seams in form of a closed curve, pseudo-seams  60 ′ are here also arranged on the panels  30  which substantially extend from a seam  50  to another seam  50  so that each panel  30  is divided in four sub-panels similar to each panel  40 . In a modification of this embodiment (not shown) further pseudo-seams extend parallel to the curved pseudo-seams on the panels  30 ,  40 , which in some embodiments, may have a slightly smaller length and a slightly lower depth as the other pseudo-seams of the panels  30 ,  40 . 
     Apart from the described pseudo-seams  60 ,  60 ′, the hatch in  FIG. 5  further indicates a surface texture  70  on the panels  30 ,  40 . Apart from the edge regions of the panels  30 ,  40  and the regions of the pseudo-seams  60 , the surface texture  70  may cover in some embodiments, the complete area of each panel  30 ,  40 . As a result, the grip of the ball  20  is improved, which facilitates the ball control at the foot, but also catching the ball by the goal keeper. The surface texture  70  may be provided by a number of individual projections or recesses on the panels  30 ,  40 . In some embodiments the individual projections or recesses may have a length in a range from about 1 mm to about 10 mm and a width in a range from about 0.5 mm to about 2 mm. They may be arranged in concentric circles on the outer circles of the panels  30 ,  40 . Alternatively, the individual projections can also be formed as conical, dome-shaped, pyramidal, etc. 
     An important aspect is that the projections do not excessively extend above the surface of the panel, which would lead to a substantial influence on the aerodynamic properties of the ball. In some embodiments, the height of the projections of the surface texture  70  may be ≦ about 0.5 mm. For example, in some embodiments, the height may be ≦ about 0.05 mm. 
     The pseudo-seams  60 , as well as the surface textures  70 , of the panels  30 ,  40  can be created with different manufacturing methods. In the method disclosed in the above mentioned EP 1 424 105 A1, each panel  30 ,  40  comprises a surface material, made for example from thermoplastic polyurethane (TPU), as well as a backing material, which may for example be a PU foam. Other exemplary backing materials are disclosed in the EP 0 894 514 A2 of applicant, which is hereby incorporated in its entirety. According to the method disclosed in EP 1 424 105 A1, for the manufacturing of a ball  20 , the surface material may be molded by deep-drawing in a mold to provide the above described three-dimensional dome shape and the pseudo-seams  60  and, if desired, the surface texture  70 . 
     In a similar manner, the backing material may be foamed, which may at the same time be interconnected to the surface material. The produced panels  30 ,  40  may have a thickness in a range from about 2 mm to about 10 mm, and in some embodiments may have a thickness in the range from about 3 mm to about 6 mm. In some embodiments, the surface material of the finished panel may extend at the edges around the backing material and can therefore be used for providing the seams  50  by gluing, welding, sewing or the like (cf. also  FIG. 6 ). 
     Apart from the described deep-drawing, other forming methods for plastic materials known to the person skilled in the art can be used for producing the panels  30 ,  40 , such as vacuum-forming. In this case, a TPU film or a film made from another suitable plastic material is heated and brought into the desired shape by means of a mold and a vacuum. Also in this method, the surface can be provided with the pseudo-seams  60  and, if desired, with the described surface texture  70  during molding. 
     Injection molding may also be used for master forming of the panels. In doing so, the surface material and the backing material for a panel can either be successively master formed and glued or can concurrently be injection molded as a two component injection molding or can be injection molded successively with the aid of an insert between layers in a mold. Materials may comprise two component foams of materials with different densities or with different colors. Foams of different colors which are arranged in a panel side by side with a transparent TPU film as surface material opens new design possibilities. A hybrid type of master forming and shaping is also conceivable, for example if the injection molded part which is not completely hardened, is additionally deformed by embossing or by other methods. 
     Moreover, it is also possible to process the surface after forming/molding, for example by etching with a laser or embossing with a suitable mechanical device. Etching with a laser is particularly advantageous, if the precision of the created structure is important as in the case of the pseudo-seams  60  (see below). A combination of the above methods may also be used, wherein some of the elements of the surface of the panels  30 ,  40  are created during molding and wherein other elements are created later by processing the surface material and/or the backing material. 
     Independent of the manufacturing methods used, the panels  30 ,  40  may comprise several layers made from different backing materials as well as several layers of surface material. Complexes of several layers of a backing material are exemplary explained in the above mentioned EP 0 894 514 A2. Using several TPU layers with different colors for the surface material enables the creation of a particular optical design. For example, a laser may subsequently selectively etch away parts of an upper TPU layer to expose a lower TPU layer of different color. This enables, for example, a simple personalization of a ball, if a long time after its fabrication individual information or graphic arts are generated with a laser for example after an important game. 
       FIGS. 6 and 7  illustrate the similarity of the shape of the seams  50  and the pseudo-seams  60 . These Figures are schematic drawings which are not true to scale. As can be seen, the seams  50  as well as the pseudo-seam  60  may have a cross section with a width of approximately 2 mm. In order to be as similar as possible to the shape of the seam  50  and to create similar aerodynamic effects, the pseudo-seam  60  may have an essentially V- or U-shaped cross section with a depth of approximately 1 mm (see  FIG. 7 ). For the long-term stability of the panel  30 ,  40 , it is advantageous if, as shown in  FIG. 7 , the pseudo-seam  60  is not only provided in the surface material  71  but also in the backing material  72 . 
     The values of a width of approximately 2 mm and a depth of approximately 1 mm, discussed above, are exemplary; however, they contribute to an optimization of the flight properties of the ball  20 . 
       FIG. 8  shows a comparison of deviations from a perfect flight path due to flutter movements for balls having the same seam and pseudo-seam distribution, but different seam cross sections and poorly processed seams, respectively. 
       FIG. 8  shows that a ball having perfect (pseudo-) seams with a width of 2 mm and a depth of 1 mm causes the lowest amount of flutter deviations. The average deviation increases for a ball having glue residues in the seams to a ball having 15% and 20% “faulty” (pseudo-) seams, respectively, up to a ball wherein all (pseudo-) seams have a width of 4 mm and a depth of 1 mm. This comparison shows that the values indicated in the claims of a width in a range from about 1 mm to about 3 mm, preferably about 2 mm and a depth in a range from about 0.5 mm to about 2 mm, preferably about 1 mm, indeed contribute to substantial improvements in the precision of flight path.