Abstract:
A golf ball with a dimple pattern designed to maximize flight characteristics employs dimples which are created by joining two or more intersecting surfaces. The invention provides for single radius or dual radius dimples, preferably including smaller radius cylinders tangentially arranged along the side of the larger cylinders. The intersection of the cylinders forms tri-cylinders, tri-semicylinders, bi-cylinders, quad-semicylinders, penta-semicylinders, or more generally n-cylinders depending upon the number of intersecting cylinders. The golf ball includes a plurality of single or dual radius dimples created by intersecting n-cylinders to create maximum turbulence on the ball during flight.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to a new golf ball dimple configuration comprised of two or more intersecting surfaces. Preferably, the intersecting surfaces are cylindrical.  
         [0002]     Dimples are provided in the surface of a golf ball in order to control and improve the flight of the ball. The dimples serve to reduce the pressure differential between the front and rear of the ball as it rotates and travels through the air. One basic criteria for the use of dimples is maximize the surface coverage of dimples on the ball without diminishing the aerodynamic symmetry of the ball.  
         [0003]     Golf balls are produced having various dimple patterns, dimple sizes, and dimple configurations so as to have a substantially constant geometric surface while improving the flight characteristics of the ball.  
       BRIEF DESCRIPTION OF THE PRIOR ART  
       [0004]     It is known in the prior art to provide a golf ball with a plurality of circular and non-circular dimples to improve ball flight. The Sullivan et al U.S. Pat. No. 6,176,793, for example, discloses a golf ball with regular circular dimples and contoured dimples. The contoured dimples have different shapes including oval, triangular, stair stepped, and sinusoidal. The Oka Pat. No. 5,338,039 discloses a golf ball having polygonal dimples with a double slope in cross-section.  
         [0005]     While prior dimple designs operate satisfactorily, they have inherent limitations with regard to maximizing dimple coverage on a golf ball surface while providing the necessary cutting action through the atmosphere that enables a golf ball to travel farther and straighter.  
       SUMMARY OF THE INVENTION  
       [0006]     It is a primary object of the invention to provide a golf ball dimple configured to generate optimal turbulence on a golf ball for improved flight characteristics and a method for creating the dimple geometry resulting in the desired configurations.  
         [0007]     The dimple has a bottom surface including multiple portions defined by at least two intersecting surfaces. Each portion of the dimple bottom corresponds with one surface. The surfaces are preferably cylindrical, and three such surfaces are provided. The first bottom portion of the dimple is defined by a first cylinder having a first radius, and second and third bottom portions are defined by second and third cylinders having equal radii which are less than the radius of the first cylinder.  
         [0008]     In a more specific embodiment, three tri-cylinders intersect to define a geometric configuration used to form the dimple bottom surface. Each tri-cylinder is defined by the intersection of one large radius and two small radius cylinders as set forth above.  
         [0009]     The dimple configuration may also be defined by a tetrahedron formed by the intersection of at least three surfaces. The intersecting surfaces may be planar or curved, such as portions of a sphere or cylinder. Preferably, the top of the tetrahedron is truncated by a planar or curved surface to define the geometric configuration of the dimple. The resulting dimples may have a triangular, quadrangular, pentagonal or hexagonal shape where the dimple volumes meet the surface of the golf ball.  
         [0010]     Such dimples are provided in a golf ball surface. All of the dimples in the ball surface may have the same configuration, or a variety of dimples of different configurations may be provided in the ball surface to maximize dimple coverage thereon. The dimples can also be arranged in the surface in a geometric pattern. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     Other objects and advantages of the invention will become apparent from a study of the following specification when viewed in the light of the accompanying drawings, in which:  
         [0012]      FIG. 1  is sectional view of a golf ball having a conventional circular dimple as known in the art;  
         [0013]      FIG. 2  is a perspective view of a regular dual radius tri-cylinder and its circumscribed prism according to the invention;  
         [0014]      FIG. 3  is a perspective view of a regular bi-cylinder and its circumscribed prism according to the invention;  
         [0015]      FIG. 4  is a perspective view of a regular tri-semicylinder and its circumscribed prism according to the invention;  
         [0016]      FIG. 5  is a plan view of a golf ball and three intersecting cylinders showing the correlation between the intersection of the surfaces of the cylinders with the golf ball surface;  
         [0017]      FIG. 6  is a detailed view of the golf ball of  FIG. 5  showing two smaller radius cylinders intersecting the golf ball surface and which are tangent to a large cylinder;  
         [0018]      FIG. 7  is a cross-sectional view of the dimple formed using the three intersecting cylinders of  FIGS. 5 and 6 ;  
         [0019]      FIGS. 8, 9 , and  10  are bottom views, respectively, of three dual radius cylinders used to form a dimple geometry according to another embodiment of the invention;  
         [0020]      FIGS. 11, 12 , and  13  are side views of the dual radius cylinders of  FIGS. 8, 9 , and  10 , respectively;  
         [0021]      FIG. 14  is a bottom view of the dual radius cylinders of  FIGS. 8, 9  and  10  showing their orientation prior to intersection;  
         [0022]      FIG. 15  is a bottom view of the geometric configuration defined by intersecting portions of the dual radius cylinders of  FIG. 14 ;  
         [0023]      FIG. 16  is a detailed perspective view of the volume of a dimple formed using the geometric configuration shown in  FIG. 15 ;  
         [0024]      FIG. 17  is a detailed perspective view of the dimple volume formed using penta-semi-cylindrical geometry;  
         [0025]      FIG. 18A  is a partial plan view of a golf ball including dimples configured with a geometry based on the dual radius cylinder of  FIG. 15 ;  
         [0026]      FIG. 18B  is a detailed plan view of a dimple from the golf ball of  FIG. 18A ;  
         [0027]      FIG. 19  is a plan view of a golf ball containing dual radii penta-semi-cylindrical dimples, symmetric dual radii tri-cylindrical dimples, and non-symmetric dual radii tri-cylindrical dimples formed in accordance with the invention;  
         [0028]      FIG. 20  is a top plan view of a tetrahedral volume formed by intersecting planar surfaces used to form a dimple geometry according to the invention;  
         [0029]      FIGS. 21-23  are top plan views of the tetrahedral volume of  FIG. 20  where the top portion of the volume has been truncated in accordance with the invention;  
         [0030]      FIGS. 24-27  are sectional views taken along lines  24 - 24 ,  25 - 25 ,  26 - 26  and  27 - 27  of  FIGS. 20-23 , respectively, showing the resulting cross-sectional dimple configurations thereof;  
         [0031]      FIG. 28  is a top plan view of a tetrahedral volume formed by intersecting curved surfaces used to form a dimple geometry according to the invention;  
         [0032]      FIGS. 29-31  are top plan views of the tetrahedral volume of  FIG. 28  where the top portion of the volume has been truncated in accordance with the invention;  
         [0033]      FIGS. 32-35  are sectional views taken along lines  32 - 32 ,  33 - 33 ,  34 - 34  and  35 - 35  of  FIGS. 28-31 , respectively, showing the resulting cross-sectional dimple configurations thereof, and  
         [0034]      FIG. 36  is a plan view of a golf ball having dimples formed using a truncated tetrehedral volume geometry. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0035]     In  FIG. 1  there is shown the cross-sectional configuration of a conventional circular dimple  2  in the surface of a golf ball  4 . The dimple has a diameter D and a depth d. A circular dimple can be thought of as being created by the intersection of a spherical surface with the surface of a golf ball, with the radius of the dimple being defined by the radius of the sphere.  
         [0036]     The present invention relates to non-circular dimple geometries formed by intersecting surfaces, such as for example, cylindrical and planar surfaces. Intersecting cylinders form tri-cylinders, tri-semicylinders, bi-cylinders, quad-semicylinders or more generally n-cylinders. Dimple volumes are formed by the intersecting n cylinders, with their long axes coplanar and equal angles between those long axes.  
         [0037]     As will be developed in detail below, the intersecting cylinders may have a pair of smaller cylinders tangent to the larger cylinder on each side to form edge radii of the dimple. This is similar to a dual radius dimple profile. A dual radius dimple is formed with a larger spherical radius (as the bottom of the dimple) tangent to a torus of smaller radius (forming an edge radius). The dual radius n-cylinder dimple bottom is formed by n cylinders and the edge radius is formed by a pair of smaller cylinders tangent to each of the larger cylinders. These are called dual radius tri-cylinders, tri-semicylinders, bi-cylinders, and quad-semicylinders. The dimples volumes are formed by the intersecting n cylinders (each with a pair of smaller tangent cylinders), with their long axes coplanar and equal angles between those long axes. If the radii of the cylinders used to form these shapes are the same, the shape is regular. Two dimensional cross-sections of these volumes (cut parallel to the plane of the long axes) are regular 2n-gons, e.g. a regular polygon of 2×n sides.  
         [0038]     Examples of the geometries used to create dimples in accordance with the invention are shown in  FIGS. 2, 3 , and  4 . More particularly,  FIG. 2  shows the geometry defined by the intersection of three cylinders of the same diameter and is referred to as a symmetric tri-cylinder  6 . The hexagonal prism circumscribed by the tri-cylinder is shown in phantom. Tri-cylinders are formed from three cylinders oriented 120° apart with a common axis of rotation central to the dimple volume. The configuration of the two-dimensional cross-section is a hexagon. When this volume is removed from a sphere to form a dimple, the intersecting surface is not planar, but rather resembles a hexagon having curved edges.  
         [0039]      FIG. 3  shows the geometry defined by the intersection of two cylinders of the same diameter and is a symmetric bi-cylinder  8  with the circumscribed square prism shown in phantom. Bi-cylinders are formed from two cylinders oriented 90° apart with a common axis of rotation central to the dimple volume. The configuration of the two-dimensional cross-sections are not squares. When this volume is removed from a sphere to form a dimple, the intersecting surface is not planar, but rather resembles a square having curved edges.  
         [0040]      FIG. 4  shows the geometry defined by the intersection of three eccentric cylinders, i.e. a tri-semicylinder  10  with a triangular circumscribed prism shown in phantom. Tri-semicylinders are formed from three cylinders oriented 120° apart with a common axis of rotation that is eccentric from the geometric center of the dimple volume. The configuration of the two-dimensional cross-sections is a triangle. When this volume is removed from a sphere to form a dimple, the intersecting surface is not planar, but rather resembles a triangle having curved edges.  
         [0041]     Quad-cylinders (not shown) are formed from four cylinders oriented 45° apart with a common axis of rotation central to the dimple volume. The configuration of the two-dimensional cross-sections is an octagon. When this volume is removed from a sphere to form a dimple, the intersecting surface is not planar, but rather resembles an octagon having curved edges.  
         [0042]     In  FIGS. 5-7 , there are shown dual radius cylinders used to form a further geometry for a further dimple configuration. A first cylinder  12  ( FIG. 5 ) has a first radius R 12  which is used to define the bottom portion  14  of a dimple  16  in the surface of a golf ball  18  shown in  FIG. 7 . That is, the bottom portion  14  of the dimple  16  has a radius R 12 . Second  20  and third  22  cylinders each have radii R 20  and R 22  which are significantly less than the radius R 12  of the first cylinder. In the preferred example shown, the radii R 20  and R 22  are equal. However, they may be different so long as they both are less than the radius R 12 . The second and third cylinders are arranged at an outer edge of the first cylinder as shown in  FIG. 5 , with the axes of all of the cylinders being parallel. The surfaces of second  20  and third  22  cylinders intersect the golf ball surface and thus define dimple bottom portions  24  and  26 , respectively. The bottom portion  24  has a radius R 20  from the second cylinder  20  and the bottom portion  26  has a radius R 22  from the third cylinder  22 .  
         [0043]     As shown in  FIG. 6 , it is preferred that the second and third cylinders overlap so that all three cylinders intersect and are tangent at the intersection. The intersection of the surfaces of the cylinders with the golf ball surface define the geometric configuration of the dimple bottom surface. The degree of overlap of the second and third cylinders will define the width of the dimple.  
         [0044]     Stated another way, the golf ball  18  has X, Y, and Z axes and is centered at (0,0,0). The first cylinder  12  that forms the bottom of the dimple has its radius parallel with the Z-axis of the ball and is centered at (0, YE, 0). The first cylinder is sliced parallel with the YZ plane at X=XA, with the central portion of the cylinder retained. The cylinder is then sliced parallel with the YZ plane at X=−XA and the central portion is retained. Next, the edge cylinders, i.e. the second  20  and third  22  cylinders are created. These cylinders have their radii centered at (XC, YC) and (−XC, YC), respectively. The surface of the three solids defined by the joinder of the three cylinders defines the geometry of the dimple. This geometry can be used to create a dimple volume removal tool which is used to create a ball geometry for forming the dimples during molding of the cover layer of the golf ball. Where the radii of the second and third cylinders are equal, the dimple defined by the intersecting cylindrical surfaces is referred to as a dual radius cylinder dimple. The first cylinder  12  has a first radius and the second and third cylinders  20 ,  22  have a second radius.  
         [0045]     FIGS.  8  is a bottom view of a dual radius cylinder  28  including a large diameter cylinder portion  30  and two small diameter cylinder portions  32 ,  34 , small cylinder portions having equal radii. As discussed above with reference to  FIGS. 5-7 , the small diameter cylinder portions define the edge of a dimple the large diameter cylinder portion defines the bottom of a dimple. Thus, the large diameter cylinder portion may be referred to as the bottom cylinder and the small diameter cylinder portions may be referred to as the edge cylinders.  
         [0046]      FIG. 9  is a-bottom view of a dual radius cylinder  36  including bottom cylinder  38  and edge cylinders  40 ,  42 , and  FIG. 10  is a bottom view of a dual radius cylinder  44  including bottom cylinder  46  and edge cylinders  48 ,  50 . The dual radius cylinders  36  and  44  are similar to the dual radius cylinder  28 .  
         [0047]      FIGS. 11-13  are side views of the dual radius cylinders  28 ,  36 , and  44  of  FIGS. 8-10 , respectively.  
         [0048]      FIG. 14  shows the orientation of the dual radius cylinders  28 ,  36 , and  44  prior to intersection and  FIG. 15  is a detailed bottom view of the geometry defined by the intersection of the surfaces of the dual radius cylinders. In  FIG. 15 , all volumes of the dual radius cylinders which do not intersect have been removed to define the geometry as shown. A perspective view of the intersection geometry of  FIG. 15  is shown in  FIG. 16 . It represents the volume of a dimple formed using the geometry. The portions  30 ,  38  and  46  are formed by the bottom cylindrical surface of the dual radius cylinders and define the bottom surface of the dimple and the portions  32 ,  34 ,  40 ,  42 ,  48 , and  50  are formed by the edge cylindrical surfaces of the dual radius cylinders and define the edge surfaces of the dimple.  
         [0049]      FIG. 17  is a perspective view of a dual radius penta-semicylinder dimple.  
         [0050]      FIG. 18A  shows a golf ball surface  52  having dimples  54  defined by a symmetric tri-cylinder as shown in  FIG. 15  formed of dual radius cylinders as shown in  FIG. 14 . The upper portion of the tri-cylinder has six surfaces, two each of surfaces  30 ,  38 , and  46 . Each dimple  54  in the ball of  FIG. 18A  also has six surfaces  54 a-f corresponding to the upper surfaces of the tri-cylinder, respectively, as shown in  FIG. 18B . The mid-portion of the tri-cylinder has another six surfaces  32 ,  34 ,  40 ,  42 ,  48 , and  50  which form the surfaces  54   g - l  in the dimple  54  in  FIG. 18B . The dimples can be sized and arranged on the ball surface in a desired pattern to maximize dimple coverage on the ball surface. The size and depth of the dimples is defined by the radii of the cylinders being used to create the geometries.  
         [0051]     A common design practice of placing dimples onto a golf ball is to begin at either the equator and work toward the pole, begin at the pole and work toward the equator, or begin at both the pole and equator and work toward the other simultaneously. It is also common that the preferred dimple sizes may not maximize surface area coverage. In this case, a variation to the n-cylinder (bi, tri, quad, penta etc.) may be employed which in effect stretches the dimple in at least one direction, similar to the way in which a circular dimple would be stretched into an ellipse. Such stretching could also result in a non-symmetric dimple. This is done to maximize surface area coverage and to create a cosmetically attractive layout.  
         [0052]     The dimple volumes can be combined to form dimple patterns with increased dimple coverage on the surface of a golf ball. By adjusting the cylindrical radius to be somewhat similar in value to the spherical radius that forms traditional spherical dimples, these new dimple shapes have edge angles, volumes, depths, and chordal diameters similar to traditional spherical dimples. Individual dimple volumes can be tuned to match volume ratios that work for traditional spherical dimple patterns. The pair of smaller tangential cylinders allows the dimple volume and dimple edge angle to be adjusted independently.  
         [0053]     A golf ball  56  including dimples formed in accordance with a preferred embodiment of the invention is shown in  FIG. 19 . The golf ball includes 12 dual radius penta-semicylinder dimples  58 ,  50  symmetric dual radius tri-cylinder dimples  60 , and 260 non-symmetric dual radius tri-cylinder dimples  62 . The pattern is repeated five times across the surface of the golf ball (i.e. five-fold symmetry) and provides 90.3% dimple surface coverage.  
         [0054]     In lieu of intersecting cylinders, intersecting surfaces may also be used to define the geometry used to create dimple configurations in accordance with the invention. In  FIGS. 20-23 , three planar surfaces intersect to form a tetrahedral volume. The top of the tetrahedron can be used to form the dimple geometry.  
         [0055]     The volume of  FIG. 20  is a full tetrahedron  64 . The cross-section of the tetrahedron taken along line  24 - 24  produces the dimple cross-sectional configuration shown in  FIG. 24 .  
         [0056]     The volume of  FIG. 21  is a truncated tetrahedron  66 . The top of the tetrahedron is truncated by a fourth planar surface which is parallel to the plane of the bottom of the tetrahedron. The cross-section of the tetrahedron  66  taken along line  25 - 25  produces the dimple cross-sectional configuration shown in  FIG. 25 .  
         [0057]     The volume of  FIG. 22  is a truncated tetrahedron  68 . The top of the tetrahedron is truncated by a fourth convex surface. The cross-section of the tetrahedron  68  taken along line  26 - 26  produces the dimple cross-sectional configuration shown in  FIG. 26 .  
         [0058]     The volume of  FIG. 23  is a truncated tetrahedron  70 . The top of the tetrahedron is truncated by a fourth concave surface. The cross-section of the tetrahedron  70  taken along line  27 - 27  produces the dimple cross-sectional configuration shown in  FIG. 27 .  
         [0059]      FIGS. 28-31  are similar to  FIGS. 20-23  except that the tetrahedral volumes are defined by curved rather than planar surfaces. The curves may be portions of a sphere or cylinder or other curved geometric shape. The truncations in  FIGS. 29-31  are formed by planar, concave, and convex surfaces, respectively, in the same manner as the truncations in  FIGS. 21-23 . The dimple configurations resulting from cross-sections taken along lines  32 - 32 ,  33 - 33 ,  34 - 34 , and  35 - 35  are shown in  FIGS. 32, 33 ,  34 , and  35 , respectively.  
         [0060]     In  FIG. 36  is shown a golf ball containing triangular dimples  72  with planar sides. The bottom surfaces of the dimples are formed by a sphere concentric with the golf ball surface but having a slightly smaller diameter than the golf ball. Where the edges of the dimples meet, small fillet radii are provided to round off the transition between adjacent dimples. Such a dimple pattern provides 93.86% coverage of the golf ball surface where the dimple depth is 0.006 inches, the ball radius is 1.693 inches, the edge angle is 15.25°, and the total volume ratio is 1.45%.  
         [0061]     While the preferred forms and embodiments of the invention have been illustrated and described, it will be apparent to those of ordinary skill in the art that various changes and modification may be made without deviating from the inventive concepts set forth above.