Patent Abstract:
The present invention provides a method for arranging dimples on a golf ball surface that significantly improves aerodynamic symmetry and minimizes parting line visibility by arranging the dimples in a pattern derived from at least one irregular domain generated from a regular or non-regular polyhedron. The method includes choosing control points of a polyhedron, generating an irregular domain based on those control points, packing the irregular domain with dimples, and tessellating the irregular domain to cover the surface of the golf ball. The control points include the center of a polyhedral face, a vertex of the polyhedron, a midpoint or other point on an edge of the polyhedron and others. The method ensures that the symmetry of the underlying polyhedron is preserved while eliminating great circles due to parting lines.

Full Description:
FIELD OF THE INVENTION 
     This invention relates to golf balls, particularly to golf balls having improved dimple patterns. More particularly, the invention relates to methods of arranging dimples on a golf ball by generating irregular domains based on polyhedrons, packing the irregular domains with dimples, and tessellating the domains onto the surface of the golf ball. 
     BACKGROUND OF THE INVENTION 
     Historically, dimple patterns for golf balls have had a variety of geometric shapes, patterns, and configurations. Primarily, patterns are laid out in order to provide desired performance characteristics based on the particular ball construction, material attributes, and player characteristics influencing the ball&#39;s initial launch angle and spin conditions. Therefore, pattern development is a secondary design step that is used to achieve the appropriate aerodynamic behavior, thereby tailoring ball flight characteristics and performance. 
     Aerodynamic forces generated by a ball in flight are a result of its velocity and spin. These forces can be represented by a lift force and a drag force. Lift force is perpendicular to the direction of flight and is a result of air velocity differences above and below the rotating ball. This phenomenon is attributed to Magnus, who described it in 1853 after studying the aerodynamic forces on spinning spheres and cylinders, and is described by Bernoulli&#39;s Equation, a simplification of the first law of thermodynamics. Bernoulli&#39;s equation relates pressure and velocity where pressure is inversely proportional to the square of velocity. The velocity differential, due to faster moving air on top and slower moving air on the bottom, results in lower air pressure on top and an upward directed force on the ball. 
     Drag is opposite in sense to the direction of flight and orthogonal to lift. The drag force on a ball is attributed to parasitic drag forces, which consist of pressure drag and viscous or skin friction drag. A sphere is a bluff body, which is an inefficient aerodynamic shape. As a result, the accelerating flow field around the ball causes a large pressure differential with high-pressure forward and low-pressure behind the ball. The low pressure area behind the ball is also known as the wake. In order to minimize pressure drag, dimples provide a means to energize the flow field and delay the separation of flow, or reduce the wake region behind the ball. Skin friction is a viscous effect residing close to the surface of the ball within the boundary layer. 
     The industry has seen many efforts to maximize the aerodynamics of golf balls, through dimple disturbance and other methods, though they are closely controlled by golf&#39;s national governing body, the United States Golf Association (U.S.G.A.). One U.S.G.A. requirement is that golf balls have aerodynamic symmetry. Aerodynamic symmetry allows the ball to fly with a very small amount of variation no matter how the golf ball is placed on the tee or ground. Preferably, dimples cover the maximum surface area of the golf ball without detrimentally affecting the aerodynamic symmetry of the golf ball. 
     In attempts to improve aerodynamic symmetry, many dimple patterns are based on geometric shapes. These may include circles, hexagons, triangles, and the like. Other dimple patterns are based in general on the five Platonic Solids including icosahedron, dodecahedron, octahedron, cube, or tetrahedron. Yet other dimple patterns are based on the thirteen Archimedian Solids, such as the small icosidodecahedron, rhomicosidodecahedron, small rhombicuboctahedron, snub cube, snub dodecahedron, or truncated icosahedron. Furthermore, other dimple patterns are based on hexagonal dipyramids. Because the number of symmetric solid plane systems is limited, it is difficult to devise new symmetric patterns. Moreover, dimple patterns based some of these geometric shapes result in less than optimal surface coverage and other disadvantageous dimple arrangements. Therefore, dimple properties such as number, shape, size, and arrangement are often manipulated in an attempt to generate a golf ball that has better aerodynamic properties. 
     U.S. Pat. No. 5,562,552 to Thurman discloses a golf ball with an icosahedral dimple pattern, wherein each triangular face of the icosahedron is split by a three straight lines which each bisect a corner of the face to form 3 triangular faces for each icosahedral face, wherein the dimples are arranged consistently on the icosahedral faces. 
     U.S. Pat. No. 5,046,742 to Mackey discloses a golf ball with dimples packed into a 32-sided polyhedron composed of hexagons and pentagons, wherein the dimple packing is the same in each hexagon and in each pentagon. 
     U.S. Pat. No. 4,998,733 to Lee discloses a golf ball formed of ten “spherical” hexagons each split into six equilateral triangles, wherein each triangle is split by a bisecting line extending between a vertex of the triangle and the midpoint of the side opposite the vertex, and the bisecting lines are oriented to achieve improved symmetry. 
     U.S. Pat. No. 6,682,442 to Winfield discloses the use of polygons as packing elements for dimples to introduce predictable variance into the dimple pattern. The polygons extend from the poles of the ball to a parting line. Any space not filled with dimples from the polygons is filled with other dimples. 
     A continuing need exists for a dimple pattern whose dimple arrangement results in a maximized surface coverage and desirable aerodynamic characteristics, including improved symmetry. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method for arranging dimples on a golf ball surface that significantly improves aerodynamic symmetry and minimizes parting line visibility by arranging the dimples in a pattern derived from at least one irregular domain generated from a regular or non-regular polyhedron. The method includes choosing control points of a polyhedron, generating an irregular domain based on those control points, packing the irregular domain with dimples, and tessellating the irregular domain to cover the surface of the golf ball. The control points include the center of a polyhedral face, a vertex of the polyhedron, a midpoint or other point on an edge of the polyhedron and others. The method ensures that the symmetry of the underlying polyhedron is preserved while minimizing great circles due to parting lines from the molding process. 
     The present invention provides methods for generating an irregular domain based on two or more control points. These methods include connecting the control points with a non-linear sketch line, patterning the sketch line in a first manner to create a first irregular domain, and optionally patterning the sketch line in a second manner to create a second irregular domain. 
     The present invention also provides methods for generating one or more irregular domains based on each set of control points. The center to vertex method, the center to midpoint method, the vertex to midpoint method, the center to edge method, and the midpoint to center to vertex method each provide a single irregular domain that can be tessellated to cover a golf ball. The center to center method, the midpoint to midpoint method, and the vertex to vertex method each provide two irregular domains that can be tessellated to cover a golf ball. In each case, the irregular domains cover the surface of the golf ball in a uniform pattern. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views: 
         FIG. 1A  illustrates a golf ball having dimples arranged by a method of the present invention;  FIG. 1B  illustrates a polyhedron face;  FIG. 1C  illustrates an element of the present invention in the polyhedron face of  FIG. 1B ;  FIG. 1D  illustrates a domain formed by a methods of the present invention packed with dimples and formed from two elements of  FIG. 1C ; 
         FIG. 2  illustrates a single face of a polyhedron having control points thereon; 
         FIG. 3A  illustrates a polyhedron face;  FIG. 3B  illustrates an element of the present invention packed with dimples;  FIG. 3C  illustrates a domain of the present invention packed with dimples formed from elements of  FIG. 3B ;  FIG. 3D  illustrates a golf ball formed by a method of the present invention formed of the domain of  FIG. 3C ; 
         FIG. 4A  illustrates two polyhedron faces;  FIG. 4B  illustrates a first domain of the present invention in the two polyhedron faces of  FIG. 4A ;  FIG. 4C  illustrates a first domain and a second domain of the present invention in three polyhedron faces;  FIG. 4D  illustrates a golf ball formed by a method of the present invention formed of the domains of  FIG. 4C ; 
         FIG. 5A  illustrates a polyhedron face;  FIG. 5B  illustrates a first domain of the present invention in a polyhedron face;  FIG. 5C  illustrates a first domain and a second domain of the present invention in three polyhedron faces;  FIG. 5D  illustrates a golf ball formed using a method of the present invention formed of the domains of  FIG. 5C ; 
         FIG. 6A  illustrates a polyhedron face;  FIG. 6B  illustrates a portion of a domain of the present invention in the polyhedron face of  FIG. 6A ;  FIG. 6C  illustrates a domain formed by the methods of the present invention;  FIG. 6D  illustrates a golf ball formed using the methods of the present invention formed of domains of  FIG. 6C ; 
         FIG. 7A  illustrates a polyhedron face;  FIG. 7B  illustrates a domain of the present invention in the polyhedron face of  FIG. 7A ;  FIG. 7C  illustrates a golf ball formed by a method of the present invention; 
         FIG. 8A  illustrates a first element of the present invention in a polyhedron face;  FIG. 8B  illustrates a first and a second element of the present invention in the polyhedron face of  FIG. 8A ;  FIG. 8C  illustrates two domains of the present invention composed of first and second elements of  FIG. 8B ;  FIG. 8D  illustrates a single domain of the present invention based on the two domains of  FIG. 8C ;  FIG. 8E  illustrates a golf ball formed using a method of the present invention formed of the domains of  FIG. 8D ; 
         FIG. 9A  illustrates a polyhedron face;  FIG. 9B  illustrates an element of the present invention in the polyhedron face of  FIG. 9A ;  FIG. 9C  illustrates two elements of  FIG. 9B  combining to form a domain of the present invention; 
         FIG. 9D  illustrates a domain formed by the methods of the present invention based on the elements of  FIG. 9C ;  FIG. 9E  illustrates a golf ball formed using a method of the present invention formed of domains of  FIG. 9D ; 
         FIG. 10A  illustrates a face of a rhombic dodecahedron;  FIG. 10B  illustrates a segment of the present invention in the face of  FIG. 10A ;  FIG. 10C  illustrates the segment of  FIG. 10B  and copies thereof forming a domain of the present invention;  FIG. 10D  illustrates a domain formed by a method of the present invention based on the segments of  FIG. 10C ; and  FIG. 10E  illustrates a golf ball formed by a method of the present invention formed of domains of  FIG. 10D . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In one embodiment, illustrated in  FIG. 1A , the present invention comprises a golf ball  10  comprising dimples  12 . Dimples  12  are arranged by packing irregular domains  14  with dimples, as seen best in  FIG. 1D . Irregular domains  14  are created in such a way that, when tessellated on the surface of golf ball  10 , they impart greater orders of symmetry to the surface than prior art balls. The irregular shape of domains  14  additionally minimize the appearance and effect of the golf ball parting line from the molding process, and allows greater flexibility in arranging dimples than would be available with regularly shaped domains. 
     The irregular domains can be defined through the use of any one of the exemplary methods described herein. Each method produces one or more unique domains based on circumscribing a sphere with the vertices of a regular polyhedron. The vertices of the circumscribed sphere based on the vertices of the corresponding polyhedron with origin (0,0,0) are defined below in Table 1. 
     
       
         
               
             
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Vertices of Circumscribed Sphere based on Corresponding 
               
               
                 Polyhedron Vertices 
               
             
          
           
               
                 Type of 
                   
               
               
                 Polyhedron 
                 Vertices 
               
               
                   
               
               
                 Tetrahedron 
                 (+1, +1, +1); (−1, −1, +1); (−1, +1, −1); (+1, −1, −1) 
               
               
                 Cube 
                 (±1, ±1, ±1) 
               
               
                 Octahedron 
                 (±1, 0, 0); (0, ±1, 0); (0, 0, ±1) 
               
               
                 Dodecahedron 
                 (±1, ±1, ±1); (0, ±1/φ, ±φ); (±1/φ, ±φ, 0); (±φ, 0, ±1/φ)* 
               
               
                 Icosahedron 
                 (0, ±1, ±φ); (±1, ±φ, 0); (±φ, 0, ±1)* 
               
               
                   
               
               
                 *φ = (1 + {square root over (5)})/2 
               
             
          
         
       
     
     Each method has a unique set of rules which are followed for the domain to be symmetrically patterned on the surface of the golf ball. Each method is defined by the combination of at least two control points. These control points, which are taken from one or more faces of a regular or non-regular polyhedron, consist of at least three different types: the center C of a polyhedron face; a vertex V of a face of a regular polyhedron; and the midpoint M of an edge of a face of the polyhedron.  FIG. 2  shows an exemplary face  16  of a polyhedron (a regular dodecahedron in this case) and one of each a center C, a midpoint M, a vertex V, and an edge E on face  16 . The two control points C, M, or V may be of the same or different types. Accordingly, six types of methods for use with regular polyhedrons are defined as follows: 
     1. Center to midpoint (C→M); 
     2. Center to center (C→C); 
     3. Center to vertex (C→V); 
     4. Midpoint to midpoint (M→M); 
     5. Midpoint to Vertex (M→V); and 
     6. Vertex to Vertex (V→V). 
     While each method differs in its particulars, they all follow the same basic scheme. First, a non-linear sketch line is drawn connecting the two control points. This sketch line may have any shape, including, but not limited, to an arc, a spline, two or more straight or arcuate lines or curves, or a combination thereof. Second, the sketch line is patterned in a method specific manner to create a domain, as discussed below. Third, when necessary, the sketch line is patterned in a second fashion to create a second domain. 
     While the basic scheme is consistent for each of the six methods, each method preferably follows different steps in order to generate the domains from a sketch line between the two control points, as described below with reference to each of the methods individually. 
     The Center to Vertex Method 
     Referring again to  FIGS. 1A-1D , the center to vertex method yields one domain that tessellates to cover the surface of golf ball  10 . The domain is defined as follows:
         1. A regular polyhedron is chosen ( FIGS. 1A-1D  use an icosahedron);   2. A single face  16  of the regular polyhedron is chosen, as shown in  FIG. 1B ;   3. Center C of face  16 , and a first vertex V 1  of face  16  are connected with any non-linear sketch line, hereinafter referred to as a segment  18 ;   4. A copy  20  of segment  18  is rotated about center C, such that copy  20  connects center C with vertex V 2  adjacent to vertex V 1 . The two segments  18  and  20  and the edge E connecting vertices V 1  and V 2  define an element  22 , as shown best in  FIG. 1C ; and   5. Element  22  is rotated about midpoint M of edge E to create a domain  14 , as shown best in  FIG. 1D .       

     When domain  14  is tessellated to cover the surface of golf ball  10 , as shown in  FIG. 1A , a different number of total domains  14  will result depending on the regular polyhedron chosen as the basis for control points C and V 1 . The number of domains  14  used to cover the surface of golf ball  10  is equal to the number of faces P F  of the polyhedron chosen times the number of edges P E  per face of the polyhedron divided by 2, as shown below in Table 2. 
     Domains Resulting from Use of Specific Polyhedra when Using the Center to Vertex Method 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
               
               
                 Domains Resulting From Use of Specific Polyhedra When 
               
               
                 Using the Center to Vertex Method 
               
             
          
           
               
                   
                 Type of 
                 Number of 
                 Number of 
                 Number of 
               
               
                   
                 Polyhedron 
                 Faces, P F   
                 Edges, P E   
                 Domains 14 
               
               
                   
               
             
          
           
               
                   
                 Tetrahedron 
                 4 
                 3 
                 6 
               
               
                   
                 Cube 
                 6 
                 4 
                 12 
               
               
                   
                 Octahedron 
                 8 
                 3 
                 12 
               
               
                   
                 Dodecahedron 
                 12 
                 5 
                 30 
               
               
                   
                 Icosahedron 
                 20 
                 3 
                 30 
               
               
                   
               
             
          
         
       
     
     The Center to Midpoint Method 
     Referring to  FIGS. 3A-3D , the center to midpoint method yields a single irregular domain that can be tessellated to cover the surface of golf ball  10 . The domain is defined as follows:
         1. A regular polyhedron is chosen ( FIGS. 3A-3D  use a dodecahedron);   2. A single face  16  of the regular polyhedron is chosen, as shown in  FIG. 3A ;   3. Center C of face  16 , and midpoint M 1  of a first edge E 1  of face  16  are connected with a segment  18 ;   4. A copy  20  of segment  18  is rotated about center C, such that copy  20  connects center C with a midpoint M 2  of a second edge E 2  adjacent to first edge E 1 . The two segments  16  and  18  and the portions of edge E 1  and edge E 2  between midpoints M 1  and M 2  define an element  22 ; and   5. Element  22  is patterned about vertex V of face  16  which is contained in element  22  and connects edges E 1  and E 2  to create a domain  14 .       

     When domain  14  is tessellated around a golf ball  10  to cover the surface of golf ball  10 , as shown in  FIG. 3D , a different number of total domains  14  will result depending on the regular polyhedron chosen as the basis for control points C and M 1 . The number of domains  14  used to cover the surface of golf ball  10  is equal to the number of vertices P V  of the chosen polyhedron, as shown below in Table 3. 
     
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Domains Resulting From Use of Specific Polyhedra When 
               
               
                 Using the Center to Midpoint Method 
               
             
          
           
               
                   
                   
                 Number of 
                 Number of 
               
               
                   
                 Type of Polyhedron 
                 Vertices, P V   
                 Domains 14 
               
               
                   
               
             
          
           
               
                   
                 Tetrahedron 
                 4 
                 4 
               
               
                   
                 Cube 
                 8 
                 8 
               
               
                   
                 Octahedron 
                 6 
                 6 
               
               
                   
                 Dodecahedron 
                 20 
                 20 
               
               
                   
                 Icosahedron 
                 12 
                 12 
               
               
                   
               
             
          
         
       
     
     The Center to Center Method 
     Referring to  FIGS. 4A-4D , the center to center method yields two domains that can be tessellated to cover the surface of golf ball  10 . The domains are defined as follows:
         1. A regular polyhedron is chosen ( FIGS. 4A-4D  use a dodecahedron);   2. Two adjacent faces  16   a  and  16   b  of the regular polyhedron are chosen, as shown in  FIG. 4A ;   3. Center C 1  of face  16   a , and center C 2  of face  16   b  are connected with a segment  18 ;   4. A copy  20  of segment  18  is rotated 180 degrees about the midpoint M between centers C 1  and C 2 , such that copy  20  also connects center C 1  with center C 2 , as shown in  FIG. 4B . The two segments  16  and  18  define a first domain  14   a ; and   5. Segment  18  is rotated equally about vertex V to define a second domain  14   b , as shown in  FIG. 4C .       

     When first domain  14   a  and second domain  14   b  are tessellated to cover the surface of golf ball  10 , as shown in  FIG. 4D , a different number of total domains  14   a  and  14   b  will result depending on the regular polyhedron chosen as the basis for control points C 1  and C 2 . The number of first and second domains  14   a  and  14   b  used to cover the surface of golf ball  10  is P F *P E /2 for first domain  14   a  and P V  for second domain  14   b , as shown below in Table 4. 
     
       
         
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 4 
               
             
             
               
                   
               
               
                 Domains Resulting From Use of Specific Polyhedra When 
               
               
                 Using the Center to Center Method 
               
             
          
           
               
                   
                 Number  
                 Number  
                 Number 
                 Number 
                 Number  
               
               
                   
                 of 
                 of First 
                 of 
                 of 
                 of Second 
               
               
                 Type of 
                 Vertices, 
                 Domains 
                 Faces,  
                 Edges,  
                 Domains 
               
               
                 Polyhedron 
                 P V   
                 14a 
                 P F   
                 P E   
                 14b 
               
               
                   
               
             
          
           
               
                 Tetrahedron 
                 4 
                 6 
                 4 
                 3 
                 4 
               
               
                 Cube 
                 8 
                 12 
                 6 
                 4 
                 8 
               
               
                 Octahedron 
                 6 
                 9 
                 8 
                 3 
                 6 
               
               
                 Dodecahedron 
                 20 
                 30 
                 12 
                 5 
                 20 
               
               
                 Icosahedron 
                 12 
                 18 
                 20 
                 3 
                 12 
               
               
                   
               
             
          
         
       
     
     The Midpoint to Midpoint Method 
     Referring to  FIGS. 5A-5D , the midpoint to midpoint method yields two domains that tessellate to cover the surface of golf ball  10 . The domains are defined as follows:
         1. A regular polyhedron is chosen ( FIGS. 5A-5D  use a dodecahedron);   2. A single face  16  of the regular polyhedron is chosen, as shown in  FIG. 5A ;   3. The midpoint M 1  of a first edge E 1  of face  16 , and the midpoint M 2  of a second edge E 2  adjacent to first edge E 1  are connected with a segment  18 ;   4. Segment  18  is patterned around center C of face  16  to form a first domain  14   a , as shown in  FIG. 5B ;   5. Segment  18 , along with the portions of first edge E 1  and second edge E 2  between midpoints M 1  and M 2 , define an element  22 ; and   6. Element  22  is patterned about vertex V which is contained in element  22  and connects edges E 1  and E 2  to create a second domain  14   b , as shown in  FIG. 5C .       

     When first domain  14   a  and second domain  14   b  are tessellated to cover the surface of golf ball  10 , as shown in  FIG. 5D , a different number of total domains  14   a  and  14   b  will result depending on the regular polyhedron chosen as the basis for control points M 1  and M 2 . The number of first and second domains  14   a  and  14   b  used to cover the surface of golf ball  10  is P F  for first domain  14   a  and P V  for second domain  14   b , as shown below in Table 5. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 5 
               
             
             
               
                   
               
               
                 Domains Resulting From Use of Specific Polyhedra When 
               
               
                 Using the Center to Center Method 
               
             
          
           
               
                   
                   
                   
                 Number of 
                 Number of 
               
               
                 Type of 
                 Number of 
                 Number of First 
                 Vertices, 
                 Second 
               
               
                 Polyhedron 
                 Faces, P F   
                 Domains 14a 
                 P V   
                 Domains 14b 
               
               
                   
               
             
          
           
               
                 Tetrahedron 
                 4 
                 4 
                 4 
                 4 
               
               
                 Cube 
                 6 
                 6 
                 8 
                 8 
               
               
                 Octahedron 
                 8 
                 8 
                 6 
                 6 
               
               
                 Dodecahedron 
                 12 
                 12 
                 20 
                 20 
               
               
                 Icosahedron 
                 20 
                 20 
                 12 
                 12 
               
               
                   
               
             
          
         
       
     
     The Midpoint to Vertex Method 
     Referring to  FIGS. 6A-6D , the midpoint to vertex method yields one domain that tessellates to cover the surface of golf ball  10 . The domain is defined as follows:
         1. A regular polyhedron is chosen ( FIGS. 6A-6D  use a dodecahedron);   2. A single face  16  of the regular polyhedron is chosen, as shown in  FIG. 6A ;   3. A midpoint M 1  of edge E 1  of face  16  and a vertex V 1  on edge E 1  are connected with a segment  18 ;   4. Copies  20  of segment  18  is patterned about center C of face  16 , one for each midpoint M 2  and vertex V 2  of face  16 , to define a portion of domain  14 , as shown in  FIG. 6B ; and   5. Segment  18  and copies  20  are then each rotated 180 degrees about their respective midpoints to complete domain  14 , as shown in  FIG. 6C .       

     When domain  14  is tessellated to cover the surface of golf ball  10 , as shown in  FIG. 6D , a different number of total domains  14  will result depending on the regular polyhedron chosen as the basis for control points M 1  and V 1 . The number of domains  14  used to cover the surface of golf ball  10  is P F , as shown in Table 6. 
     
       
         
               
             
               
               
               
               
             
               
               
               
               
             
           
               
                 TABLE 6 
               
             
             
               
                   
               
               
                 Domains Resulting From Use of Specific Polyhedra When 
               
               
                 Using the Midpoint to Vertex Method 
               
             
          
           
               
                   
                   
                 Number of 
                 Number of 
               
               
                   
                 Type of Polyhedron 
                 Faces, P F   
                 Domains 14 
               
               
                   
               
             
          
           
               
                   
                 Tetrahedron 
                 4 
                 4 
               
               
                   
                 Cube 
                 6 
                 6 
               
               
                   
                 Octahedron 
                 8 
                 8 
               
               
                   
                 Dodecahedron 
                 12 
                 12 
               
               
                   
                 Icosahedron 
                 20 
                 20 
               
               
                   
               
             
          
         
       
     
     The Vertex to Vertex Method 
     Referring to  FIGS. 7A-7C , the vertex to vertex method yields two domains that tessellate to cover the surface of golf ball  10 . The domains are defined as follows:
         1. A regular polyhedron is chosen ( FIGS. 7A-7C  use an icosahedron);   2. A single face  16  of the regular polyhedron is chosen, as shown in  FIG. 7A ;   3. A first vertex V 1  face  16 , and a second vertex V 2  adjacent to first vertex V 1  are connected with a segment  18 ;   4. Segment  18  is patterned around center C of face  16  to form a first domain  14   a , as shown in  FIG. 7B ;   5. Segment  18 , along with edge E 1  between vertices V 1  and V 2 , defines an element  22 ; and   6. Element  22  is rotated around midpoint M 1  of edge E 1  to create a second domain  14   b.          

     When first domain  14   a  and second domain  14   b  are tessellated to cover the surface of golf ball  10 , as shown in  FIG. 7C , a different number of total domains  14   a  and  14   b  will result depending on the regular polyhedron chosen as the basis for control points V 1  and V 2 . The number of first and second domains  14   a  and  14   b  used to cover the surface of golf ball  10  is P F  for first domain  14   a  and P F *P E /2 for second domain  14   b , as shown below in Table 7. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 7 
               
             
             
               
                   
               
               
                 Domains Resulting From Use of Specific Polyhedra When 
               
               
                 Using the Vertex to Vertex Method 
               
             
          
           
               
                   
                   
                   
                 Number of 
                 Number of 
               
               
                 Type of 
                 Number of 
                 Number of First 
                 Edges per 
                 Second 
               
               
                 Polyhedron 
                 Faces, P F   
                 Domains 14a 
                 Face, P E   
                 Domains 14b 
               
               
                   
               
             
          
           
               
                 Tetrahedron 
                 4 
                 4 
                 3 
                 6 
               
               
                 Cube 
                 6 
                 6 
                 4 
                 12 
               
               
                 Octahedron 
                 8 
                 8 
                 3 
                 12 
               
               
                 Dodecahedron 
                 12 
                 12 
                 5 
                 30 
               
               
                 Icosahedron 
                 20 
                 20 
                 3 
                 30 
               
               
                   
               
             
          
         
       
     
     While the six methods previously described each make use of two control points, it is possible to create irregular domains based on more than two control points. For example, three, or even more, control points may be used. The use of additional control points allows for potentially different shapes for irregular domains. An exemplary method using a midpoint M, a center C and a vertex V as three control points for creating one irregular domain is described below. 
     The Midpoint to Center to Vertex Method 
     Referring to  FIGS. 8A-8E , the midpoint to center to vertex method yields one domain that tessellates to cover the surface of golf ball  10 . The domain is defined as follows:
         1. A regular polyhedron is chosen ( FIGS. 8A-8E  use an icosahedron);   2. A single face  16  of the regular polyhedron is chosen, as shown in  FIG. 8A ;   3. A midpoint M 1  on edge E 1  of face  16 , Center C of face  16  and a vertex V 1  on edge E 1  are connected with a segment  18 , and segment  18  and the portion of edge E 1  between midpoint M 1  and vertex V 1  define a first element  22   a , as shown in  FIG. 8A ;   4. A copy  20  of segment  18  is rotated about center C, such that copy  20  connects center C with a midpoint M 2  on edge E 2  adjacent to edge E 1 , and connects center C with a vertex V 2  at the intersection of edges E 1  and E 2 , and the portion of segment  18  between midpoint M 1  and center C, the portion of copy  20  between vertex V 2  and center C, and the portion of edge E 1  between midpoint M 1  and vertex V 2  define a second element  22   b , as shown in  FIG. 8B ;   5. First element  22   a  and second element  22   b  are rotated about midpoint M 1  of edge E 1 , as seen in  FIG. 8C , to define two domains  14 , wherein a single domain  14  is bounded solely by portions of segment  18  and copy  20  and the rotation  18 ′ of segment  18 , as seen in  FIG. 8D .       

     When domain  14  is tessellated to cover the surface of golf ball  10 , as shown in  FIG. 8E , a different number of total domains  14  will result depending on the regular polyhedron chosen as the basis for control points M, C, and V. The number of domains  14  used to cover the surface of golf ball  10  is equal to the number of faces P F  of the polyhedron chosen times the number of edges P E  per face of the polyhedron, as shown below in Table 8. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 8 
               
             
             
               
                   
               
               
                 Domains Resulting From Use of Specific Polyhedra When 
               
               
                 Using the Midpoint to Center to Vertex Method 
               
             
          
           
               
                   
                 Type of 
                 Number of 
                 Number of 
                 Number of 
               
               
                   
                 Polyhedron 
                 Faces, P F   
                 Edges, P E   
                 Domains 14 
               
               
                   
               
             
          
           
               
                   
                 Tetrahedron 
                 4 
                 3 
                 12 
               
               
                   
                 Cube 
                 6 
                 4 
                 24 
               
               
                   
                 Octahedron 
                 8 
                 3 
                 24 
               
               
                   
                 Dodecahedron 
                 12 
                 5 
                 60 
               
               
                   
                 Icosahedron 
                 20 
                 3 
                 60 
               
               
                   
               
             
          
         
       
     
     While the methods described previously provide a framework for the use of center C, vertex V, and midpoint M as the only control points, other control points are useable. For example, a control point may be any point P on an edge E of the chosen polyhedron face. When this type of control point is used, additional types of domains may be generated, though the mechanism for creating the irregular domain(s) may be different. An exemplary method, using a center C and a point P on an edge, for creating one such irregular domain is described below. 
     The Center to Edge Method 
     Referring to  FIGS. 9A-9E , the center to edge method yields one domain that tessellates to cover the surface of golf ball  10 . The domain is defined as follows:
         1. A regular polyhedron is chosen ( FIGS. 9A-9E  use an icosahedron);   2. A single face  16  of the regular polyhedron is chosen, as shown in  FIG. 9A ;   3. Center C of face  16 , and a point P 1  on edge E 1  are connected with a segment  18 ;   4. A copy  20  of segment  18  is rotated about center C, such that copy  20  connects center C with a point P 2  on edge E 2  adjacent to edge E 1 , where point P 2  is positioned identically relative to edge E 2  as point P 1  is positioned relative to edge E 1 , such that the two segments  18  and  20  and the portions of edges E 1  and E 2  between points P 1  and P 2 , respectively, and a vertex V, which connects edges E 1  and E 2 , define an element  22 , as shown best in  FIG. 9B ; and   5. Element  22  is rotated about midpoint M 1  of edge E 1  or midpoint M 2  of edge E 2 , whichever is located within element  22 , as seen in  FIGS. 9B-9C , to create a domain  14 , as seen in  FIG. 9D .       

     When domain  14  is tessellated to cover the surface of golf ball  10 , as shown in  FIG. 9E , a different number of total domains  14  will result depending on the regular polyhedron chosen as the basis for control points C and P 1 . The number of domains  14  used to cover the surface of golf ball  10  is equal to the number of faces P F  of the polyhedron chosen times the number of edges P E  per face of the polyhedron divided by 2, as shown below in Table 9. 
     
       
         
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 9 
               
             
             
               
                   
               
               
                 Domains Resulting From Use of Specific Polyhedra When 
               
               
                 Using the Center to Edge Method 
               
             
          
           
               
                   
                 Type of 
                 Number of 
                 Number of 
                 Number of 
               
               
                   
                 Polyhedron 
                 Faces, P F   
                 Edges, P E   
                 Domains 14 
               
               
                   
               
             
          
           
               
                   
                 Tetrahedron 
                 4 
                 3 
                 6 
               
               
                   
                 Cube 
                 6 
                 4 
                 12 
               
               
                   
                 Octahedron 
                 8 
                 3 
                 12 
               
               
                   
                 Dodecahedron 
                 12 
                 5 
                 30 
               
               
                   
                 Icosahedron 
                 20 
                 3 
                 30 
               
               
                   
               
             
          
         
       
     
     Though each of the above described methods has been explained with reference to regular polyhedrons, they may also be used with certain non-regular polyhedrons, such as Archimedean Solids, Catalan Solids, or others. The methods used to derive the irregular domains will generally require some modification in order to account for the non-regular face shapes of the non-regular solids. An exemplary method for use with a Catalan Solid, specifically a rhombic dodecahedron, is described below. 
     A Vertex to Vertex Method for a Rhombic Dodecahedron 
     Referring to  FIGS. 10A-10E , a vertex to vertex method based on a rhombic dodecahedron yields one domain that tessellates to cover the surface of golf ball  10 . The domain is defined as follows:
         1. A single face  16  of the rhombic dodecahedron is chosen, as shown in  FIG. 10A ;   2. A first vertex V 1  face  16 , and a second vertex V 2  adjacent to first vertex V 1  are connected with a segment  18 , as shown in  FIG. 10B ;   3. A first copy  20  of segment  18  is rotated about vertex V 2 , such that it connects vertex V 2  to vertex V 3  of face  16 , a second copy  24  of segment  18  is rotated about center C, such that it connects vertex V 3  and vertex V 4  of face  16 , and a third copy  26  of segment  18  is rotated about vertex V 1  such that it connects vertex V 1  to vertex V 4 , all as shown in  FIG. 10C , to form a domain  14 , as shown in  FIG. 10D ;       

     When domain  14  is tessellated to cover the surface of golf ball  10 , as shown in  FIG. 10E , twelve domains will be used to cover the surface of golf ball  10 , one for each face of the rhombic dodecahedron. 
     After the irregular domain(s) is created using any of the above methods, the domain(s) may be packed with dimples in order to be usable in creating golf ball  10 . There are no limitations on how the dimples are packed. There are likewise no limitations to the dimple shapes or profiles selected to pack the domains. Though the present invention includes substantially circular dimples in one embodiment, dimples or protrusions (brambles) having any desired characteristics and/or properties may be used. For example, in one embodiment the dimples may have a variety of shapes and sizes including different depths and widths. In particular, the dimples may be concave hemispheres, or they may be triangular, square, hexagonal, catenary, polygonal or any other shape known to those skilled in the art. They may also have straight, curved, or sloped edges or sides. To summarize, any type of dimple or protrusion (bramble) known to those skilled in the art may be used with the present invention. The dimples may all fit within each domain, as seen in  FIGS. 1A and 1D , or dimples may be shared between one or more domains, as seen in  FIGS. 3C-3D , so long as the dimple arrangement on each independent domain remains consistent across all copies of that domain on the surface of a particular golf ball. Alternatively, the tessellation can create a pattern that covers more than about 60%, preferably more than about 70% and preferably more than about 80% of the golf ball surface without using dimples. 
     In other embodiments, the domains may not be packed with dimples, and the borders of the irregular domains may instead comprise ridges or channels. In golf balls having this type of irregular domain, the one or more domains or sets of domains preferably overlap to increase surface coverage of the channels. Alternatively, the borders of the irregular domains may comprise ridges or channels and the domains are packed with dimples. 
     When the domain(s) is patterned onto the surface of a golf ball, the arrangement of the domains dictated by their shape and the underlying polyhedron ensures that the resulting golf ball has a high order of symmetry, equaling or exceeding 12. The order of symmetry of a golf ball produced using the method of the current invention will depend on the regular or non-regular polygon on which the irregular domain is based. The order and type of symmetry for golf balls produced based on the five regular polyhedra are listed below in Table 10. 
     
       
         
               
             
               
               
               
               
             
           
               
                 TABLE 10 
               
             
             
               
                   
               
               
                 Symmetry of Golf Ball of the Present Invention as a Function 
               
               
                 of Polyhedron 
               
             
          
           
               
                   
                 Type of 
                   
                 Symmetrical 
               
               
                   
                 Polyhedron 
                 Type of Symmetry 
                 Order 
               
               
                   
               
               
                   
                 Tetrahedron 
                 Chiral Tetrahedral Symmetry 
                 12 
               
               
                   
                 Cube 
                 Chiral Octahedral Symmetry 
                 24 
               
               
                   
                 Octahedron 
                 Chiral Octahedral Symmetry 
                 24 
               
               
                   
                 Dodecahedron 
                 Chiral Icosahedral Symmetry 
                 60 
               
               
                   
                 Icosahedron 
                 Chiral Icosahedral Symmetry 
                 60 
               
               
                   
               
             
          
         
       
     
     These high orders of symmetry have several benefits, including more even dimple distribution, the potential for higher packing efficiency, and improved means to mask the ball parting line. Further, dimple patterns generated in this manner may have improved flight stability and symmetry as a result of the higher degrees of symmetry. 
     In other embodiments, the irregular domains do not completely cover the surface of the ball, and there are open spaces between domains that may or may not be filled with dimples. This allows dissymmetry to be incorporated into the ball. 
     While the preferred embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not of limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. For example, while the preferred polyhedral shapes have been provided above, other polyhedral shapes could also be used. Thus the present invention should not be limited by the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Technology Classification (CPC): 0