Abstract:
A golf ball approaching zero land area is disclosed herein. The golf ball has an innersphere with a plurality of lattice members. Each of the plurality of lattice members has an apex and the golf ball of the present invention conforms with the 1.68 inches requirement for USGA-approved golf balls. The interconnected lattice members form a plurality of polygons, preferably hexagons and pentagons. Each of the lattice members preferably has a continuous contour.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     Not Applicable  
       FEDERAL RESEARCH STATEMENT  
       [0002]     [Not Applicable] 
       BACKGROUND OF INVENTION  
       [0003]     1. Field of the Invention  
         [0004]     The present invention relates to an aerodynamic surface geometry for a golf ball. More specifically, the present invention relates to a golf ball having a lattice structure.  
         [0005]     2. Description of the Related Art  
         [0006]     Golfers realized perhaps as early as the 1800&#39;s that golf balls with indented surfaces flew better than those with smooth surfaces. Hand-hammered gutta-percha golf balls could be purchased at least by the 1860&#39;s, and golf balls with brambles (bumps rather than dents) were in style from the late 1800″s to 1908. In 1908, an Englishman, William Taylor, received a British patent for a golf ball with indentations (dimples) that flew better and more accurately than golf balls with brambles. A.G. Spalding &amp; Bros., purchased the U.S. rights to the patent (embodied possibly in U.S. Pat. No. 1,286,834 issued in 1918) and introduced the GLORY ball featuring the TAYLOR dimples. Until the 1970s, the GLORY ball, and most other golf balls with dimples had 336 dimples of the same size using the same pattern, the ATTI pattern. The ATTI pattern was an octahedron pattern, split into eight concentric straight line rows, which was named after the main producer of molds for golf balls.  
         [0007]     The only innovation related to the surface of a golf ball during this sixty year period came from Albert Penfold who invented a mesh-pattern golf ball for Dunlop. This pattern was invented in 1912 and was accepted until the 1930&#39;s. A combination of a mesh pattern and dimples is disclosed in Young, U.S. Pat. No. 2,002,726, for a Golf Ball, which issued in 1935.  
         [0008]     The traditional golf ball, as readily accepted by the consuming public, is spherical with a plurality of dimples, with each dimple having a circular cross-section. Many golf balls have been disclosed that break with this tradition, however, for the most part these non-traditional golf balls have been commercially unsuccessful.  
         [0009]     Most of these non-traditional golf balls still attempt to adhere to the Rules Of Golf as set forth by the United States Golf Association (“USGA”) and The Royal and Ancient Golf Club of Saint Andrews (“R&amp;A”). As set forth in Appendix III of the Rules of Golf, the weight of the ball shall not be greater than 1.620 ounces avoirdupois (45.93 gm), the diameter of the ball shall be not less than 1.680 inches (42.67 mm) which is satisfied if, under its own weight, a ball falls through a 1.680 inches diameter ring gauge in fewer than 25 out of 100 randomly selected positions, the test being carried out at a temperature of 23±1° C., and the ball must not be designed, manufactured or intentionally modified to have properties which differ from those of a spherically symmetrical ball.  
         [0010]     One example is Shimosaka et al., U.S. Pat. No. 5,916,044, for a Golf Ball that discloses the use of protrusions to meet the 1.68 inch (42.67 mm) diameter limitation of the USGA and R&amp;A. The Shimosaka patent discloses a golf ball with a plurality of dimples on the surface and a few rows of protrusions that have a height of 0.001 to 1.0 mm from the surface. Thus, the diameter of the land area is less than 42.67 mm.  
         [0011]     Another example of a non-traditional golf ball is Puckett et al., U.S. Pat. No. 4,836,552 for a Short Distance Golf Ball, which discloses a golf ball having brambles instead of dimples in order to reduce the flight distance to half of that of a traditional golf ball in order to play on short distance courses.  
         [0012]     Another example of a non-traditional golf ball is Pocklington, U.S. Pat. No. 5,536,013 for a Golf Ball, which discloses a golf ball having raised portions within each dimple, and also discloses dimples of varying geometric shapes, such as squares, diamonds and pentagons. The raised portions in each of the dimples of Pocklington assist in controlling the overall volume of the dimples.  
         [0013]     Another example is Kobayashi, U.S. Pat. No. 4,787,638 for a Golf Ball, which discloses a golf ball having dimples with indentations within each of the dimples. The indentations in the dimples of Kobayashi are to reduce the air pressure drag at low speeds in order to increase the distance.  
         [0014]     Yet another example is Treadwell, U.S. Pat. No. 4,266,773 for a Golf Ball, which discloses a golf ball having rough bands and smooth bands on its surface in order to trip the boundary layer of air flow during flight of the golf ball.  
         [0015]     Aoyama, U.S. Pat. No. 4,830,378, for a Golf Ball With Uniform Land Configuration, discloses a golf ball with dimples that have triangular shapes. The total land area of Aoyama is no greater than 20% of the surface of the golf ball, and the objective of the patent is to optimize the uniform land configuration and not the dimples.  
         [0016]     Another variation in the shape of the dimples is set forth in Steifel, U.S. Pat. No. 5,890,975 for a Golf Ball And Method Of Forming Dimples Thereon. Some of the dimples of Steifel are elongated to have an elliptical cross-section instead of a circular cross-section. The elongated dimples make it possible to increase the surface coverage area. A design patent to Steifel, U.S. Pat. No. 406,623, has all elongated dimples.  
         [0017]     A variation on this theme is set forth in Moriyama et al., U.S. Pat. No. 5,722,903, for a Golf Ball, which discloses a golf ball with traditional dimples and oval-shaped dimples.  
         [0018]     A further example of a non-traditional golf ball is set forth in Shaw et al., U.S. Pat. No. 4,722,529, for Golf Balls, which discloses a golf ball with dimples and 30 bald patches in the shape of a dumbbell for improvements in aerodynamics.  
         [0019]     Another example of a non-traditional golf ball is Cadorniga, U.S. Pat. No. 5,470,076, for a Golf Ball, which discloses each of a plurality of dimples having an additional recess. It is believed that the major and minor recess dimples of Cadorniga create a smaller wake of air during flight of a golf ball.  
         [0020]     Oka et al., U.S. Pat. No. 5,143,377, for a Golf Ball, discloses circular and non-circular dimples. The non-circular dimples are square, regular octagonal and regular hexagonal. The non-circular dimples amount to at least forty percent of the 332 dimples on the golf ball. These non-circular dimples of Oka have a double slope that sweeps air away from the periphery in order to make the air turbulent.  
         [0021]     Machin, U.S. Pat. No. 5,377,989, for Golf Balls With Isodiametrical Dimples, discloses a golf ball having dimples with an odd number of curved sides and arcuate apices to reduce the drag on the golf ball during flight.  
         [0022]     Lavallee et al., U.S. Pat. No. 5,356,150, discloses a golf ball having overlapping elongated dimples to obtain maximum dimple coverage on the surface of the golf ball.  
         [0023]     Oka et al., U.S. Pat. No. 5,338,039, discloses a golf ball having at least forty percent of its dimples with a polygonal shape. The shapes of the Oka golf ball are pentagonal, hexagonal and octagonal.  
         [0024]     Ogg, U.S. Pat. No. 6,290,615 for a Golf Ball Having A Tubular Lattice Pattern discloses a golf ball with a non-dimple aerodynamic pattern.  
         [0025]     The HX®RED golf ball and the HX® BLUE golf ball from Callaway Golf Company of Carlsbad, Calif. are golf balls with non-dimple aerodynamic patterns. The aerodynamic patterns generally consist of a tubular lattice network that defines hexagons and pentagons on the surface of the golf ball. Each hexagon is generally defined by thirteen facets, six of the facets being shared facets and seven of the facets been internal facets.  
       SUMMARY OF INVENTION  
       [0026]     The present invention is able to provide a golf ball that meets the USGA requirements, and provides a minimum land area to trip the boundary layer of air surrounding a golf ball during flight in order to create the necessary turbulence for greater distance. The present invention is able to accomplish this by providing a golf ball with a lattice structure.  
         [0027]     One aspect of the present invention is a golf ball with an innersphere having a surface and a plurality of lattice members. Each lattice members has a cross-sectional contour with an apex at the greatest extent from the center of the golf ball. The apices of the lattice members define an outersphere. The plurality of lattice members are connected together to form a predetermined pattern on the golf ball. The predetermined pattern is composed of a plurality of multi-faceted polygons, each of which has at least fourteen facets.  
         [0028]     Yet another aspect of the present invention is a golf ball having a sphere with a lattice configuration. The sphere has a diameter in the range of 1.60 to 1.70 inches. The lattice configuration includes a plurality of lattice members. Each of the lattice members has an apex that has a distance from the bottom of each lattice member in a range of 0.005 to 0.010 inch resulting in an outersphere with a diameter of at least 1.68 inches.  
         [0029]     A further aspect of the present invention is a golf ball comprising a plurality of lattice members, each having a continuous surface contour. The lattice members may form a plurality of multi-faceted polygons, each of which has at least twenty-four facets.  
         [0030]     Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0031]      FIG. 1  is an equatorial view of a golf ball of the present invention.  
         [0032]      FIG. 2  is a CAD drawing of the equatorial view of the golf ball in  FIG. 1  illustrating the multi-faceted aerodynamic pattern.  
         [0033]      FIG. 3  is an isolated top plan view of a multi-faceted hexagon of the golf ball of  FIG. 1 .  
         [0034]      FIG. 4  is a CAD drawing of the multi-faceted hexagon of  FIG. 3 .  
         [0035]      FIG. 5  is a CAD drawing of a multi-faceted hexagon of a prior art golf ball.  
         [0036]      FIG. 6  is an enlarged, isolated, cross-sectional view of a projection extending from an innersphere surface of a golf ball of the present invention.  
         [0037]      FIG. 7  is an enlarged, isolated, cross-sectional view of a projection extending from an innersphere surface of a golf ball of the present invention.  
         [0038]      FIG. 8  is an enlarged, isolated, cross-sectional view of a projection extending from an innersphere surface of a golf ball of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0039]     As shown in  FIG. 1  and, a golf ball is generally designated  20 . The golf ball  20  may be a two-piece golf ball, a three-piece golf ball, or a greater multi-layer golf ball. The golf ball  20  may be wound or solid. The golf ball  20  is preferably constructed as set forth in U.S. Pat. No. 6,117,024, for a Golf Ball With A Polyurethane Cover, which pertinent parts are hereby incorporated by reference. Additionally, the core of the golf ball  20  may be solid, hollow, or filled with a fluid, such as a gas or liquid, or have a metal mantle. The cover of the golf ball  20  may be any suitable material. A preferred cover for a three-piece golf ball is composed of a thermoset polyurethane material. Alternatively, the cover may be composed of a thermoplastic polyurethane, ionomer blend, ionomer rubber blend, ionomer and thermoplastic polyurethane blend, or like materials. A preferred cover material for a two-piece golf ball is a blend of ionomers. Those skilled in the pertinent art will recognize that other cover materials may be utilized without departing from the scope and spirit of the present invention. The golf ball  20  may have a finish of one or two basecoats and/or one or two top coats.  
         [0040]     The golf ball  20  preferably has an innersphere  21  ( FIG. 6 ) with an innersphere surface  22 . The golf ball  20  also has an equator  24  (shown by dashed line) generally dividing the golf ball  20  into a first hemisphere  26  and a second hemisphere  28 . A first pole  30  is generally located ninety degrees along a longitudinal arc from the equator  24  in the first hemisphere  26 . A second pole  32  is generally located ninety degrees along a longitudinal arc from the equator  24  in the second hemisphere  28 .  
         [0041]     Descending toward the surface  22  of the innersphere  21  are a plurality of lattice members  40 . In a preferred embodiment, the lattice members  40  are constructed from quintic Bézier curves. However, those skilled in the pertinent art will recognize that the lattice members  40  may have other similar shapes. The lattice members  40  are connected together to form a lattice structure  42  on the golf ball  20 . The interconnected lattice members  40  form a plurality of polygons encompassing discrete areas of the surface  22  of the innersphere  21 . Most of these discrete bounded areas  44  are preferably hexagonal-shaped bounded areas  44   a  and  44   b , with a few pentagonal-shaped bounded areas  44   c . In the embodiment of  FIGS. 1 and 2 , there are 332 polygons. In the preferred embodiment, each lattice member  40  is preferably connected to at least one other lattice member  40 . Each lattice member  40  preferably connects to at least two other lattice members  40  at a vertex. Most of the vertices are the congruence of three lattice members  40 , however, some vertices are the congruence of four lattice members  40 . The length of each lattice member  40  preferably ranges from 0.150 inch to 0.160 inch.  
         [0042]     The preferred embodiment of the present invention has reduced the land area of the surface of the golf ball  20  to almost zero, since preferably only a line of each of the plurality of lattice members  40  lies on a phantom outersphere  23  ( FIG. 6 ) of the golf ball  20 , which preferably has a diameter of at least 1.68 inches. More specifically, the land area of a traditional golf ball is the area forming a sphere of at least 1.68 inches for USGA and R&amp;A conforming golf balls. This land area is traditionally minimized with dimples that are concave with respect to the spherical surface of the traditional golf ball, resulting in land area on the non-dimpled surface of the golf ball. The golf ball  20  of the present invention, however, has only a line extending along an apex  50  of each of the lattice members  40  that lies on and defines the outersphere  23  of the golf ball  20 .  
         [0043]     Traditional golf balls were designed to have the dimples trip the boundary layer on the surface of a golf ball in flight to create a turbulent flow for greater lift and reduced drag. The golf ball  20  of the present invention has the lattice structure  42  to trip the boundary layer of air about the surface of the golf ball  20  in flight.  
         [0044]     As shown in  FIG. 6 , the outersphere  23  is shown by a dashed line. In the preferred embodiment, the apex  50  of each lattice member  40  lies on the outersphere  23 , and the outersphere represents a diameter of the golf ball of 1.68 inches. One difference between the golf ball  20  of the present invention and traditional, dimpled golf balls is that for the golf ball  20  of the present invention, a smaller portion of the golf ball is located at or near the outersphere  23  compared to a traditional golf ball. Thus, for the golf ball  20  of the present invention, a sphere having a diameter slightly less than that of the outersphere  23  would contain a greater percent of the volume of the golf ball  20  compared to the same sphere for a traditional dimpled golf ball.  
         [0045]     As shown in  FIG. 7 , the height H T , of each of the plurality of lattice members  40  from the innersphere  21  to an apex  50  of the lattice member  40  will vary in order to have the golf ball  20  meet or exceed the 1.68 inches requirement. For example, if the diameter, D I  (as shown in  FIG. 6 ) of the innersphere  21  is 1.666 inches, then the distance H T  in  FIG. 7  is preferably 0.007 inch, since the lattice member  40  on one side of the golf ball  20  is combined with a corresponding lattice member  40  on the opposing side of the golf ball  20  to reach the USGA requirement of 1.68 inches for the diameter of a golf ball. In an alternative embodiment, the innersphere  21  has a diameter, D I , that is less than 1.666 inches and each of the plurality of lattice members  40  has a height, H T , that is greater than 0.007 inch. For example, in one alternative embodiment, the diameter D I , of the innersphere  21  is 1.662 while the height, H T , of each of the lattice members  40  is 0.009 inch, thereby resulting in an outersphere  23  with a diameter of 1.68 inches. In a preferred embodiment of the invention, the distance H T  ranges from 0.005 inch to 0.010 inch. The width of each of the apices  50  is minimal, since each apex lies along an arc of a lattice member  40 . In theory, the width of each apex  50  should approach the width of a line. In practice, the width of each apex  50  of each lattice member  40  is determined by the precision of the mold utilized to produce the golf ball  20 .  
         [0046]     As shown in  FIGS. 6-8 , each lattice member  40  is constructed using a radius R T , of an imaginary tube set within the innersphere  21  of the golf ball  20 . The very top portion of the imaginary tube extends beyond the surface  22  of the innersphere  21 . In a preferred embodiment the radius R T  is approximately 0.048 inch. The apex  50  of the lattice member  40  preferably lies on the radius R T , of the imaginary tube. Points  55   a  and  55   b  represent the inflection points of the lattice member  40 , and inflection points  55   a  and  55   b  both preferably lie on the radius R T , of the imaginary tube. At inflection points  55   a  and  55   b , the surface contour of the lattice member preferably changes from concave to convex. Points  57  and  57   a  represent the beginning of the lattice member  40 , extending beyond the surface  22  of the innersphere  21 . The surface contour of the lattice member  40  is preferably concave between point  57  and inflection point  55   a , convex between inflection point  55   a  and inflection point  55   b , and concave between inflection point  55   b  and point  57   a.    
         [0047]     As shown in  FIG. 7 , a blend length L B  is the distance from point  57  to apex  50 . Table One provides preferred blend lengths for the lattice members  40  of a preferred embodiment. An entry angle α EA  is the angle relative the tangent line at the inflection point  55   a  and a tangent line through the apex  50 . In a preferred embodiment, the entry angle α EA  is 14.8 degrees.  
                                                     TABLE ONE                               Blend Radius,   Blend length,   Tube Height,       Bounded area   Number   R B     L B     H T                                  Pentagon, 44c   12   0.15 inch   0.075 inch   0.00795 inch       Hexagon, 44b   60   0.20 inch   0.090 inch   0.00945 inch       Hexagon, 44a   260   0.23 inch   0.100 inch   0.01045 inch                  
 
         [0048]     Each lattice member  40  preferably has a contour that has a first concave section  54  (between point  57  and inflection point  55   a ), a convex section  56  (between inflection point  55   a  and inflection point  55   b ), and a second concave section  58  (between inflection point  55   b  and point  57   a ). In a preferred embodiment, each of the lattice members  40  has a continuous contour with a changing radius along the entire surface contour. The radius R T  of each of the lattice members  40  is preferably in the range of 0.020 inch to 0.070 inch, more preferably 0.040 inch to 0.050 inch, and most preferably 0.048 inch. The inflection points  55   a  and  55   b , which define the start and end of the convex section  56 , are defined by the radius R T . The curvature of the convex section  56 , however, is not necessarily determined by the radius R T . Instead, one of ordinary skill in the art will appreciate that the convex section  56  may have any suitable curvature.  
         [0049]     As discussed above, the lattice members  40  are interconnected to form a plurality of polygons. The intersection of two lattice members  40  forms a crease, whose surface is then smoothed, or blended, using a blend radius R B . Table One provides preferred blend radii for the lattice members  40  of the preferred embodiment. The blend radius R B  is preferably in the range of 0.100 inch to 0.300 inch, more preferably 0.15 inch to 0.25 inch, and most preferably 0.23 inch for the majority of lattice members  40 . By way of example, in the hexagon-bounded area illustrated in  FIGS. 3 and 4 , facets  70  and  80  are crease regions that have been blended using a blend radius R B .  
         [0050]     The continuous surface contour of the golf ball  20  allows for a smooth transition of air during the flight of the golf ball  20 . The air pressure acting on the golf ball  20  during its flight is driven by the contour of each lattice member  40 . Some traditional dimples have a curvature discontinuity at their transition points. Reducing the discontinuity of the contour reduces the discontinuity in the air pressure distribution during the flight of the golf ball  20 , which reduces the separation of the turbulent boundary layer that is created during the flight of the golf ball  20 .  
         [0051]     The surface contour each of the lattice members  40  is preferably based on a fifth degree Bézier polynomial having the formula: 
 
 P ( t )=3 B   i   J   n,i ( t ) 0≦ t≧ 1 
 
 wherein P(t) are the parametric defining points for both the convex and concave portions of the cross section of the lattice member  40 , the Bézier blending function is 
 
 J   n,i ( t )=( n   i ) t   i (1− t ) n−1  
 
 and n is equal to the degree of the defining Bézier blending function, which for the present invention is preferably five. t is a parametric coordinate normal to the axis of revolution of the dimple. B i  is the value of the ith vertex of defining the polygon, and i=n+1. A more detailed description of the Bézier polynomial utilized in the present invention is set forth in  Mathematical Elements For Computer Graphics , Second Edition, McGraw-Hill, Inc., David F. Rogers and J. Alan Adams, pages 289-305, which are hereby incorporated by reference. 
 
         [0052]     For the lattice members  40 , the equations defining the cross-sectional shape require the location of the points  57  and  57   a , the inflection points  55   a  and  55   b , the apex  50 , the entry angle α EA , the radius of the golf ball R ball , the radius of the imaginary tube R T , the curvature at the apex  50 , and the tube height, H T .  
         [0053]     Additionally, as shown in  FIG. 8 , tangent magnitude points also define the bridge curves. Tangent magnitude point T 1  corresponds to the apex  50  (convex curve), and a preferred tangent magnitude value is 0.5. Tangent magnitude point T 2  corresponds to the inflection point  55   a  (convex curve), and a preferred tangent magnitude value is 0.5. Tangent magnitude point T 3  corresponds to the inflection point  55   a  (concave curve), and a preferred tangent magnitude value is 1. Tangent magnitude point T 4  corresponds to the point  57  (concave curve), and a preferred tangent magnitude value is 1.  
         [0054]     This information allows for the surface contour of the lattice member  40  to be designed to be continuous throughout the lattice member  40 . In constructing the contour, two associative bridge curves are prepared as the basis of the contour. A first bridge curve is overlaid from the point  57  to the inflection point  55   a , which eliminates the step discontinuity in the curvature that results from having true arcs point continuous and tangent. The second bridge curve is overlaid from the inflection point  55   a  to the apex  50 . The attachment of the bridge curves at the inflection point  55   a  allows for equivalence of the curvature and controls the surface contour of the lattice member  40 . The dimensions of the curvature at the apex  50  also controls the surface contour of the lattice member. The shape of the contour may be refined using the parametric stiffness controls available at each of the bridge curves. The controls allow for the fine tuning of the shape of each of the lattice members by scaling tangent and curvature poles on each end of the bridge curves.  
         [0055]     An additional feature of the present invention is the multi-faceted hexagon-bounded area, as shown in  FIGS. 3 and 4 . The hexagon-bounded area  44   a  of the present invention has a greater number of facets than the hexagon-bounded area  44 ′ of the prior art ( FIG. 5 ), which is the HX®RED golf ball and HX®BLUE golf ball from Callaway Golf Company of Carlsbad, Calif. The increase in facets is due to the blended regions at the intersection of lattice members. The hexagon-bounded area  44   a  has inner facets  70 , 70   a  and  72 , and outer facets  80  and  82 . In a preferred embodiment, hexagon-bounded area  44   a  has twenty inner facets  70 ,  70   a  and  72 , and eighteen outer facets  80  and  82 . The hexagon-bounded area  44 ′ of the prior art had seven inner facets  170  and  172  (innersphere surface) and six outer facets. The greater number of facets in the hexagon bounded area  44   a  of the present invention allows for better control of the surface contour, thereby resulting in better lift and drag properties, which results in greater distance.  
         [0056]     From the foregoing it is believed that those skilled in the pertinent art will recognize the meritorious advancement of this invention and will readily understand that while the present invention has been described in association with a preferred embodiment thereof, and other embodiments illustrated in the accompanying drawings, numerous changes, modifications and substitutions of equivalents may be made therein without departing from the spirit and scope of this invention which is intended to be unlimited by the foregoing except as may appear in the following appended claims. Therefore, the embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following appended claims.