This invention relates to golf balls and more particularly to a surface configuration of a golf ball.
For many years golf balls have been made with surface indentations or depressions, called dimples, to improve their aerodynamic properties in flight. Many efforts have been made to select the optimum number, size and shape of dimples as well as their disposition around the outer surface of a generally spherically shaped golf ball.
Dimples on golf balls are typically circular in elevation cross section, but a number of other designs are also utilized, including truncated cones, dimples within dimples, elliptical surfaces, hemispherical (or single radius) dimples, and dual radius dimples. For example, U.S. Pat. No. 4,979,747 shows dimples having a frusto-contical elevation view cross section, and U.S. Pat. No. 5,005,838 shows dimples having complex shapes.
Different dimple shapes have different aerodynamic properties, and therefore, result in different performance characteristics. For example, a single radius dimple provides a more gradual entry of the airflow into the dimple, while a dual radius dimple provides a more abrupt entry of the airflow into the dimple. (A single radius dimple is one in which the elevation cross sectional shape of the dimple can be described by one radius, and dual radius dimple is one in which the elevation cross section is described by two radii.)
It has been found that the single radius dimple is the most optimal dimple shape for a high performance three-piece wound golf ball. By contrast, the dual radius dimple is the most optimal shape design for two-piece distance balls for providing the desired golf ball flight trajectory. These dimple choices are based on the current view that the higher spinning performance balls require a more gradual entry of the airflow into the dimple to create the desired aerodynamic effects, whereas the low spinning distance ball requires a more abrupt entry of the airflow into the dimple to create the desired aerodynamic effect.
There are a number of hybrid type balls which do not fall squarely within either the three-piece performance category or the two-piece distance category. For example, two-piece performance balls and three-piece distance balls are hybrid balls which behave like performance balls for certain shots and like distance balls for other shots. As used herein the term “hybrid ball” is used to refer to a two piece performance ball, a three-piece distance ball, or any other ball which behaves like a performance ball for certain shots and like a distance ball for other shots.
It has been found, for instance that a dimple pattern utilizing dual radius dimples allows for a lower more boring trajectory for a distance two-piece ball, whereas a pattern utilizing single radius dimples allows for a more consistent flight trajectory for high performance three-piece balls.
A need exists for a dimple pattern (and dimple shape) which takes into account the unique characteristics of the hybrid ball (i.e. the fact that it performs as a distance ball for certain shots, and as a performance ball for other shots) to provide optimum performance. The goal is to provide a ball that (i) provides slightly longer overall distance than a ball utilizing either all single radius dimples or all dual radius dimples, and (ii) has a significantly lower trajectory, as exhibited by the lower rear trajectory value.
Thus, it is an object of the present invention to provide a golf ball dimple pattern that optimizes the performance characteristics of the hybrid ball.
It is another object of the present invention to provide a hybrid golf ball that provides a slightly longer overall distance and a lower trajectory than the prior art hybrid balls.
It is another object of the invention to provide a golf ball having a dimple pattern that incorporates dimples of different sizes to maximize the aerodynamic qualities for each such dimple shape.
It is yet another object of the present invention to provide a golf ball having superior distance, trajectory and flight stability.
These and other objectives of the present invention are accomplished according to the present invention by providing a golf ball having a dimple pattern which incorporates dimples of different shapes to maximize the aerodynamic properties of the ball. The dimple shapes may be selected from any known dimple shapes, including but not limited to truncated cones, squares, triangles, dimples within dimples, elliptical surfaces, single radius dimples, and dual radius dimples. The invention allows for the combination of any of the possible dimple shapes into a single dimple pattern to allow a more optimized golf ball flight trajectory.
The golf ball of the preferred embodiment is a hybrid ball in which the dimple pattern on the surface of the ball includes both single radius and dual radius dimples in order to achieve the most optimal flight performance. This hybrid ball is allowed to best utilize the aspects of single radius dimples for shots where it behaves more like a performance three-piece ball, and the aspects of dual radius dimples for shots where it behaves like a distance ball, while maintaining good flight performance and control with a combination of both. The ball provides slightly longer overall distance, and a significantly lower trajectory than the prior art hybrid balls. This is a much desired property for this type of ball.
The dimples are arranged by dividing the outer spherical surface of a golf ball into a plurality of polygonal configurations, including pentagons, squares and triangles for locating a plurality of dimples on the outer surface of the golf ball. The polygonal configurations of this invention are preferably a combination of regular pentagons, squares and triangles to cover the outer surface. This first plurality of polygonal configurations is generally referred to herein as a “rhombicosadodecahedron”. The rhombicosadodecahedron is further characterized by a uniform pattern of pentagons formed over the outer surface each bounded by triangles and squares.
The preferred embodiment utilizes a pattern of 402 dimples arranged in the construction of the rhombicosadodecahedron. A pair of first polygonal configurations, each located on opposite sides of the outer surface, include one of the two poles symmetrically arranged within its boundaries. The outer surface has a plurality of dimples of different sizes. In one embodiment, the dimples are of first, second and third sizes and are generally located to have a first pattern associated with the pentagons, a second pattern associated with the squares, and a third pattern associated with the triangles.
In another embodiment of the invention, the outer surface of the golf ball includes a plurality of parting lines along great circle paths of the ball for further dividing the first plurality of polygonal configurations into a second plurality of polygonal configurations, each of which are smaller than the polygonal configurations of the first polygonal configurations. The dimples are arranged over the outer surface by being associated with both the first and the second plurality of polygonal configurations.
The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown and wherein:
Referring now in more detail to the drawings, the invention will now be described in more detail. The golf ball 5 may have a unit construction in a single piece, molded from a suitable rubber or plastic composition; it may be of a two-piece ball construction having a separately applied cover applied around a core; it may be of a three piece wound ball with a liquid or solid center; or it may be a multipiece solid golf ball. The cover is molded from a material suitable for golf balls. It may be molded as two separate hemispherical half-shells which are then compression molded or injection molded around the core.
The dimple configuration will normally be applied to the ball during the molding of the cover around the core by using appropriately shaped negative molds containing the dimple pattern in reverse. The molded golf ball having the desired dimple configuration may be then painted. Alternately, painting may be unnecessary for one piece golf balls using a cover having a suitable compounding of the composition used.
Accordingly, the scope of this invention provides a golf ball mold whose molding surface contains a uniform pattern to give the golf ball a dimple configuration superior to those of the prior art. The invention is preferably described in terms of the golf ball that results from the mold, but could be described within the scope of this invention in terms of the mold structure that produces a golf ball.
To assist in locating the dimples on the golf ball, the golf ball 5 of this invention has its outer spherical surface partitioned by the projection of a plurality of polygonal configurations onto the outer surface. That is, the formation or division that results from a particular arrangement of different polygons on the outer surface of a golf ball is referred to herein as a “plurality of polygonal configurations.” A view of one side of a golf ball 5 showing a preferred division of the golf ball's outer surface 7 is illustrated in
In the preferred embodiment, a polygonal configuration known as a rhombicosadodecahedron is projected onto the surface of a sphere. A rhombicosadodecahedron is a type of polyhedron which contains thirty (30) squares, twenty (20) polyhedra of one type, and twelve (12) polyhedra of another type. The term “rhombicosadodecahedron” is derived from “dodecahedron,” meaning a twelve (12) sided polyhedron; “icosahedron,” meaning a twenty (20) sided polyhedron, and “rhombus” meaning a four sided polyhedron.
The rhombicosadodecahedron of the preferred embodiment is comprised of thirty (30) squares 12, twelve (12) pentagons 10, and twenty (20) triangles 14. It has a uniform pattern of pentagons with each pentagon bounded by triangles and squares. The uniform pattern is achieved when each regular pentagon 10 has only regular squares 12 adjacent to its five boundary lines, and when a regular triangle 14 extends from each of the five vertices of the pentagon. Five (5) squares 12 and five (5) triangles 14 form a set of polygons around each pentagon. Two boundary lines of each square are common with two pentagon boundary lines, and each triangle has its vertices common with three pentagon vertices.
The outer surface of the ball is further defined by a pair of poles and an equatorial great circle path around the surface. A great circle path is defined by the intersection between the spherical surface and a plane which passes through the center of the sphere. An infinite number of great circle paths may be drawn on any sphere. The equatorial great circle path in the preferred embodiment corresponds to a mold parting line which separates the golf ball into two hemispheres. The mold parting line is located from the poles in substantially the same manner as the equator of the Earth is located from the North Pole and the South Pole.
Referring to
Dimples are placed on the outer surface of the golf ball based on segments of the plurality of polygonal configurations described above. In the preferred embodiment, three (3) dimples are associated with each triangle, five (5) dimples are associated with each square, and sixteen (16) dimples are associated with each pentagon. The term “associated” as used herein in relation to the dimples and the polyhedra means that the polyhedra are used as a guide for placing the dimples.
The dimple configuration of the preferred embodiment is shown in
Dimples 200, 202 and 204 (from all three sets of dimples) are also used to form a second pattern associated with the squares 12. All sides 208 of each square 12 are intersected by dimples 202 from the second set of dimples, and all squares have the same general second pattern arrangement of dimples.
Dimples 202 from the second set of dimples form a third pattern associated with the triangles 14. All sides 210 of each triangle are intersected by a dimple 202 from this second set of dimples. All triangles have this same general third pattern arrangement of dimples. The mold parting line 30 is the only dimple free great circle path on this ball.
The ball of the preferred embodiment utilizes two different types of dimples having two different cross sections, single radius dimples 200 and 204 and dual radius dimples 202. In the single radius dimple (
Dimple size is measured by a diameter and depth generally according to the teachings of U.S. Pat. No. 4,936,587 (the '587 patent), which is included herein by reference thereto. An exception to the teaching of the '587 patent is the measurement of the depth, which is discussed below. A cross-sectional view through a typical single radius dimple 6 is illustrated in
The dimple dimensions for the preferred embodiment are set forth below:
It is understood that the following dimple size ranges are within the scope of this invention: dimples 200 from the first set may have a diameter in the range of 0.150 inches to 0.160 inches; dimples 202 from the second set may have a diameter in the range of 0.140 inches to 0.150 inches; dimples 204 from the third set may have a diameter in the range of 0.135 inches to 0.145 inches; all dimples, 200, 202 and 204 may have a depth in the range of 0.0056 inches to 0.0078 inches; the major radius may be in the range of 0.34 inches to 0.80 inches; and the minor radius (for dimple 202) may be in the range of 0.10 inches to 0.12 inches.
The following test data illustrates the improved performance of the dimple pattern of the present invention. All balls identified below are hybrids
As shown above, the ball of the present invention, which utilizes both single radius and dual radius dimples, provides slightly longer overall distance than a ball utilizing either all single radius dimples or all dual radius dimples, and it has a significantly lower trajectory, as exhibited by the lower rear trajectory value. This is a much desired property for the hybrid ball.
The plurality of dimples on the surface of the ball shown in
A secondary partitioning of the outer surface of the golf ball is superimposed on the rhombicosadodecahedron previously described, as illustrated in
A possible dimple pattern for the polygonal configuration of
Another embodiment of the polygonal configurations including certain parting lines is illustrated in
The previous embodiments illustrate dimples which are formed as generally circular in a plan view of each dimple. Other embodiments of the present invention include dimples which are non-circular in form, as illustrated in
Dimples at the equatorial great circle path defining a mold parting line 30 are divided into two parts, as illustrated in
The dimples may be placed on the outer surface of the golf ball to intersect all of the parting lines constructed on the outer surface, none of the parting lines, or only some of the parting lines on the outer surface. When great circle paths are not intersected by dimples they become true parting lines for defining the dimple pattern.
While a preferred embodiment of the invention has been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims. For example, it is understood that the invention is not limited to a dimple pattern defined by the rhombicosadodecahedron.
This application claims the benefit of provisional application No. 60/138,078 filed Jun. 8,1999.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US00/40067 | 6/5/2000 | WO | 00 | 11/27/2001 |
Publishing Document | Publishing Date | Country | Kind |
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WO00/74797 | 12/14/2000 | WO | A |
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Number | Date | Country | |
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60138078 | Jun 1999 | US |