Games using tangible projectile – Golf – Ball
Reexamination Certificate
1999-07-30
2001-06-05
Young, Lee (Department: 3729)
Games using tangible projectile
Golf
Ball
C473S378000, C473S379000, C473S380000, C473S381000, C473S382000, C473S383000, C473S384000
Reexamination Certificate
active
06241627
ABSTRACT:
This invention relates to a dimpled golf ball having improved flight performance.
BACKGROUND OF THE INVENTION
Golf balls are generally formed with a multiplicity of dimples of circular plane shape on their surface in order to improve their aerodynamic characteristics. It is well known that the dimpled golf balls fly better than dimple-free golf balls having a smooth spherical surface.
The flight distance of golf balls is dictated by many factors including the initial velocity and spin rate of the ball, drag and lift acting on the ball in flight, and weather conditions. It has been considered difficult to make theoretical analysis on golf balls with the aim of increasing their flight distance.
For improving the flight performance of the ball except for the initial velocity which is largely governed by the material of the ball, a number of attempts of tailoring dimples relating to the geometrical factors of the ball have been made. Such attempts include, for example, increasing the diameter of dimples, using plural types of dimples having different diameters, increasing or decreasing the depth of dimples, changing the shape of dimples from circular one to polygonal and other shapes, and increasing or decreasing the number of dimples. Certain improvements have been made.
None of these attempts succeeded in developing a golf ball having satisfactory flight performance when judged from the skill level of professional golfers. Further improvement and development of golf balls are desired.
SUMMARY OF THE INVENTION
An object of the invention is to provide a dimpled golf ball having improved flight performance.
Regarding a dimpled golf ball wherein the spherical surface is assumed to be substantially a regular icosahedron or pseudo-icosahedron (20-sided polyhedron) having twenty triangles, and those dimples arranged in each triangle constitute an arrangement unit, the inventor has succeeded in optimizing the arrangement, diameter and depth of dimples.
The invention is directed to a golf ball having plural types of dimples on a spherical surface. The spherical surface is assumed to be substantially a regular icosahedron or pseudo-icosahedron having twenty triangles. Apexes of five triangles join together at a vertex. Those dimples arranged in each triangle constitute an arrangement unit.
In a first embodiment, a first dimple having the smallest diameter is located substantially at the vertex, and second dimples having a greater diameter than the first dimple are closely and equidistantly arranged around the first dimple. When a pentagon which circumscribes the second dimples is drawn with its center at the vertex, the average depth of those dimples located within the pentagon is up to 85% of the average depth of those dimples located in the remaining areas outside the pentagon.
In a second embodiment, first dimples having the smallest diameter are equidistantly arranged substantially around the vertex. When a pentagon which circumscribes the first dimples is drawn with its center at the vertex, the average depth of those dimples located within the pentagon is up to 95% of the average depth of those dimples located in the remaining areas outside the pentagon.
The golf balls having dimples arranged according to the first and second embodiments, when hit with a driver, exhibit excellent flight performance and aerodynamic symmetry.
REFERENCES:
patent: 4142727 (1979-03-01), Shaw et al.
patent: 4729861 (1988-03-01), Lynch
patent: 4858923 (1989-08-01), Gobush
patent: 4915390 (1990-04-01), Golbush
patent: 5062644 (1991-11-01), Lee
patent: 5080367 (1992-01-01), Lynch
patent: 5149100 (1992-09-01), Melvin
patent: 5470075 (1995-11-01), Nesbitt
patent: 5575477 (1996-11-01), Hwang
patent: 5766098 (1998-06-01), Molitor
Ihara Keisuke
Kasashima Atsuki
Shimosaka Hirotaka
Bridgestone Sports Co. Ltd.
Kim Paul D.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Young Lee
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