Golf ball dimple pattern

Abstract: A golf ball (10) has dimples (30,32,34) formed in its outer spherical surface (12) and arranged in a geodesic pattern defined by a plurality of imaginary grid lines (14) which divide the outer spherical surface (12) into a truncated octahedron having six square regions (16) and eight hexagonal regions (18). Each hexagonal region (18) is defined by six of the grid lines (14) which form a spherical equilateral hexagon (H) having six sides of equal length and three diagonals of equal length. The dimples (30,32,34) are arranged so that alternating sides of the hexagon (H) each intersect at least two dimples (32), and each diagonal intersects at least seven dimples (30,34). The golf ball (10) has a total of 374 dimples including 126 dimples with a diameter of 0.145 inch, 200 dimples with a diameter of 0.165 inch, and 48 dimples with a diameter of 0.125 inch. The 374 dimples cover 76.8% of the outer spherical surface (12) of the golf ball (10).

Description: This invention relates generally to golf balls and, in particular, to a geodesic pattern for arranging dimples in an outer spherical surface of a golf ball. Dimples provide golf balls with important aerodynamic characteristics. For example, dimples create a blanket of air turbulence around a golf ball which reduces drag and thereby increases distance. Dimples also enhance lift as a golf ball spins in a backward direction after being struck by a golf club. When a golf ball is backspinning, the dimples improve air flow above the golf ball thereby resulting in increased air pressure below the golf ball which enhances lift. It is known that lift and drag can be altered by arranging the dimples in different geodesic patterns such as icosahedrons, octahedrons and dodecahedrons. If lift is increased, a golf ball has a higher trajectory. If drag is reduced, a golf ball travels farther. A proper combination of lift and drag gives satisfactory performance. Presently, three types of golf balls are being used. Three-piece golf balls have a small core around which windings are wrapped, and a cover in which dimples are formed. Two-piece golf balls have a large core with no windings, and a cover with dimples formed therein. One-piece golf balls have a unitary core and cover. A further aerodynamic characteristic of a golf ball is spin rate which is determined by cover hardness relative to core hardness. Generally, three-piece golf balls have a higher spin rate than two-piece and one-piece golf balls. Therefore, a particular dimple pattern may result in satisfactory performance on a three-piece golf ball but unsatisfactory performance on a two-piece or one-piece golf ball. Geodesic dimple patterns for golf balls have many variations. One such variation is a truncated octahedron wherein dimples are arranged in six square regions and eight hexagonal regions. Truncated octahedral dimple patterns are disclosed in U.S. Patent Nos. 4,765,626 to Gobush and 4,886,277 (corresponding to WO 90/00916) to Mackey. Since most commercially available golf balls have a cover constructed with a straight seam or parting line lying on an equator of the golf ball, the dimple patterns disclosed by Gobush and Mackey utilize false seams or-false parting lines to improve their geometric symmetry. The straight seam or parting line is actually a dimple-free great circular path on the outer spherical surface of a golf ball that results from a conventional molding process used in making golf balls. U.S. Patent No. 4,653,758 to Karsten Solheim discloses a method of making a golf ball wherein the cover has a seam that is undulating rather than straight and thus does not require the use of false seams to improve the geometric symmetry of the dimple pattern. In addition to being geometrically symmetrical, a golf ball should also have what is referred to as "spherical symmetry" by the United States Golf Association (USGA). Spherical or aerodynamic symmetry is determined by launching a golf ball so that it spins about one axis and then launching the same golf ball so that it spins about another axis. Any differences in length of flight (i.e. carry) and time of flight are noted. In order to conform to the USGA Rules of Golf, these differences must not be more than three yards for carry or greater than 0.20 seconds for flight time. While the dimple patterns discloses in the above-mentioned Gobush and Mackey patents may improve a golf ball's geometric symmetry, they may adversely affect its aerodynamic symmetry. An object of the present invention is to provide a geodesic dimple pattern for golf balls which results in improved aerodynamic characteristics on three-piece, two-piece and one-piece golf balls. Another object of the present invention is to provide a geodesic dimple pattern for golf balls which reduces drag and enhances lift. A further object of the present invention is to provide a geodesic dimple pattern for golf balls that results in a golf ball being both geometrically and aerodynamically symmetrical without utilizing false seams or false parting lines. The present invention provides a golf ball having an outer spherical surface with dimples formed therein and arranged in a geodesic pattern defined by a plurality of immaginary grid lines which divide the outer spherical surface into a truncated octahedron having six square regions and eight hexagonal regions. Each hexagonal region is defined by six of the grid lines which form a spherical equilateral hexagon having six sides of equal length and three diagonals of equal length. In accordance with the invention, the dimples are arranged so that alternating sides of the hexagon each intersect at least two dimples and each diagonal intersects at least seven dimples. Preferably, each square region contains a first plurality of dimples, and each hexagonal region contains a second plurality of dimples which is greater than the first plurality of dimples. Preferably, the outer spherical surface of the golf ball has no great circular paths that are dimple free. In the preferred embodiment of the present invention, the dimples intersected by the alternating sides of each hexagon have a first diameter and two of the dimples intersected by each diagonal of each hexagon have a second diameter. The first diameter is larger than the second diameter. The golf ball has a total of 374 dimples including 200 dimples with the first diameter which is approximately 4.191 mm (0.165 inch), 48 dimples with the second diameter which is approximately 3.175 mm (0.125 inch), and 126 dimples with a third diameter of approximately 3.683 (0.145 inch). A preferred embodiment of the dimpled golf ball of the invention will now be described in detail, with reference to the accompanying drawings, in which: Fig. 1 is a top plan or polar view of a golf ball with a dimple pattern according to the present invention; Figs. 2 and 3 are side elevational or equatorial views of the golf ball shown in Fig. 1; and Fig. 4 is a schematic view of one hexagonal region of the dimple pattern shown in Figs. 1 and 2. Referring to Figs. 1 and 2, a golf ball 10 has an outer spherical surface 12 divided by a plurality of imaginary grid lines 14 into a geodesic pattern such as a truncated octahedron having six identical square regions 16 and eight identical hexagonal regions 18. Two of the square regions 16 are located in polar sections of the outer spherical surface 12 while the other four square regions 16 are located in equatorial sections of the outer spherical surface 12. Each square region 16 is bounded by four hexagonal regions 18, and each hexagonal region 18 is bounded by four square regions 16 and two hexagonal regions 18. The truncated octahedral dimple pattern of the present invention has the same appearance when viewed in either the polar view of Fig. 1 or the equatorial view of Fig. 2. As best seen in Fig. 4, each hexagonal region 18 is defined by six of the grid lines 14 which form a spherical equilateral hexagon H with six vertex points A, B, C, D, E, F and six sides AB, BC, CD, DE, EF, FA of equal length. Each hexagon H also has three diagonals of equal length designated AD, BE, CF in Fig. 3 extending between the six vertex points A, B, C, D, E, F. The three diagonals AD, BE, CF intersect at a central point G. Referring to Fig. 3, the golf ball 10 includes a core (not shown) and a cover 20 formed of upper and lower substantially hemispherical sections 22 and 24. A seam or parting line 26 exists where the hemispherical sections 22, 24 of the cover 20 are joined together during a conventional molding process. The cover 20 may be compression molded or injection molded. The seam 26 extends generally along an equator 28 of the golf ball 10, and is formed in an undulating manner similar to that disclosed in U.S. Patent No. 4,653,758 granted March 31, 1987 to Karsten Solheim, incorporated herein by reference. Dimples 30, 32 and 34 are formed in the outer spherical surface 12 and are arranged in the square and hexagonal regions 16, 18 of the truncated octohedral pattern. Thirteen of the dimples 30 are contained in each square region 16, and six of the dimples 30 are contained in each of the hexagonal regions 18. Twenty-five of the dimples 32 and six of the dimples 34 are also contained inside each of the hexagonal regions 18. The dimples 34 are arranged adjacent the vertex points of the hexagonal regions 18. Each square region 16 contains a plurality of thirteen dimples, and each hexagonal region 18 contains a plurality of thirty-seven dimples so that the golf ball 10 has a total of 374 dimples formed in its outer surface 12. In each of the hexagonal regions 18, the dimples 30, 32 and 34 are arranged so that alternating sides BC, DE, FA of the hexagon H each intersect two of the dimples 32, while the diagonals AD, BE, CF each radially intersect a total of seven dimples (i.e. five of the dimples 30, and two of the dimples 34). This dimple arrangement results in improved aerodynamic characteristics for the golf ball 10 by reducing drag and enhancing lift. In the preferred embodiment of the golf ball 10, the dimples 30 have a diameter of approximately 3.683 mm (0.145 inch), the dimples 32 have a diameter of approximately 4.191 mm (0.165 inch), and the dimples 34 have a diameter of approximately 3.175 mm (0.125 inch). The dimples 30 and 32 have a depth of about 0.2921 mm (0.0115 inch), and the dimples 34 have a depth of about 0.2667 mm (0.0105 inch). Therefore, the diameter to depth ratios for the dimples 30, 32 and 34 are 12.6 to 1, 14.3 to 1, and 11.9 to 1, respectively. The golf ball 10 has a total of 374 dimples which includes 126 dimples with the 3.683 mm (0.145 inch) diameter, 200 dimples with the 4.191 mm (0.165 inch) diameter, and 48 dimples with the 3.175 mm (0.125 inch) diameter. Since 76.8 per cent of the outer surface 12 of the golf ball 10 is covered by the dimples 30, 32 and 34, only 23.2 per cent of the outer surface 12 is undimpled. The golf ball 10 may be of either the three-piece type which has a small core around which windings are wrapped, the two-piece type which has a large core and no windings, or the one-piece type which has a unitary core and cover. It will be understood that the present invention provides an improved dimple pattern for use on three-piece, two-piece and one-piece golf balls. Unlike the dimple patterns disclosed in U.S. Patent Nos. 4,765,626 to Gobush and 4,886,277 to Mackey, the dimple pattern of the present invention does not utilize any false seams or false parting lines to improve its geometric symmetry. Furthermore, with the dimple pattern of the present invention, the outer spherical surface of a golf ball has no great circular paths that are dimple free.

Claims: A golf ball (10) comprising: an outer spherical surface (12) with dimples (30, 32, 34) formed therein, said dimples (30, 32, 34) being arranged in a geodesic pattern defined by a plurality of imaginary grid lines (14) which divide said outer spherical surface (12) into a truncated octahedron having six square regions (16) and eight hexagonal regions (18); each of said hexagonal regions (18) being defined by six of said grid lines (14) which form a spherical equilateral hexagon having six sides (AB, BC, CD, DE, EF, FA) of equal length and three diagonals (AD, BE, CF) of equal length; characterized by said dimples (30, 32, 34) being arranged so that alternating sides (BC, DE, FA) of said hexagon (18) each intersect at least two dimples (32) and each of said diagonals (AD, BE, CF) intersects at least seven dimples (30, 34). The golf ball (10) of claim 1, wherein the two dimples (32) intersected by said alternating sides (BC, DE, FA) have a first diameter and wherein two (34) of the seven dimples (30, 34) intersected by each said diagonal (AD, BE, CF) have a second diameter. The golf ball (10) of claim 2, wherein five (30) of the seven dimples (30, 34) intersected by each said diagonal (AD, BE, CF) have said first diameter. The golf ball (10) of claim 3, wherein said first diameter is larger than said second diameter. The golf ball (10) of claim 4, wherein said first diameter is approximately 4.191 mm (0.165 inch), and said second diameter is approximately 3.175 mm (0.125 inch). The golf ball (10) of any preceding claim, further comprising a core disposed inside a cover (20), and wherein said cover (20) is made of two substantially hemispherical sections (22, 24) which are molded together when the golf ball (10) is manufactured. The golf ball (10) of claim 6, wherein said two substantially hemispherical sections (22, 24) of said cover (20) are joined together at a seam (26) which extends generally along an equator (28) of the golf ball (10). The golf ball (10) of claim 7, wherein said seam (26) extends generally along said equator (28) in an undulating manner. The golf ball (10) of any preceding claim, wherein a total of 374 dimples (30, 32, 34) are arranged in said geodesic pattern. The golf ball (10) of claim 9, wherein 200 dimples (32) have said first diameter, 48 dimples (34) have said second diameter, and 126 dimples (30) have a third diameter which is smaller than said first diameter but larger than said second diameter. The golf ball (10) of claim 10, wherein said third diameter is approximately 3.683 mm (0.145 inch). The golf ball (10) of any one of claims 9 to 11, wherein approximately 77 percent of said outer spherical surface (12) is covered by the 374 dimples (30, 32, 34), and wherein approximately 23 per cent of said outer spherical surface (12) is undimpled. The golf ball (10) of claim 1, wherein each of said six square regions (16) contains a first plurality of dimples (30), and each of said hexagonal regions (18) contains a second plurality of dimples (30) which is greater than said first plurality of dimples (30); and wherein said outer spherical surface (12) has no great circular paths that are dimple free. The golf ball (10) of claim 13, wherein: said first plurality of dimples (30) comprises 13 dimples; said second plurality of dimples (30) comprises 37 dimples; and said outer spherical surface (12) has a total of 374 dimples formed therein. The golf ball (10) of claim 13 or claim 14, further comprising a cover (20) in which said dimples (30, 32, 34) are formed, said cover (20) including two substantially hemispherical sections (22, 24) joined together at a seam (26) which extends generally along an equator (28) of the golf ball (10) in an undulating manner.

Inventors: SANCHEZ RICHARD R, SANCHEZ, RICHARD R.
Applicants: KARSTEN MFG CORP, KARSTEN MANUFACTURING CORPORATION
Application year: 1993
Main classification: A63B37
IPC codes: A63B37