Golf ball

Abstract

A golf ball is provided that has a hard sphere core or layer that exhibits a controlled vibrational response. The vibrational response may be controlled by tailoring the stiffness or damping of the sphere with at least one element, such as a groove(s) or any other type of indentation in the hard sphere core. The groove (or grooves) serves to locally reduce the wall thickness of the hollow metal sphere core, thereby reducing the stiffness of the core by allowing larger deformations under a load without significantly reducing the total mass of the core. This results in a golf ball that is legal for play and capable of drive distances essentially equivalent to those of currently available high performance golf balls, but that also maintains a high moment of inertia, allowing less hooks and slices during play.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present application is a continuation of U.S. patent application Ser. No. 10 / 756,185, filed Jan. 13, 2004, which is a continuation of U.S. Pat. No. 6,705,957, issued Mar. 16, 2004, which is a continuation of U.S. Pat. No. 6,004,225, issued Dec. 21, 1999, which claims priority to U.S. Provisional Patent Application No. 60 / 036,196, filed Jan. 16, 1997.FIELD OF THE INVENTION [0002] The present invention relates generally to an improved multi-piece golf ball, and more particularly, a multi-piece golf ball including a hollow metal sphere. BACKGROUND OF THE INVENTION [0003] Various types of regulation golf balls have been proposed. In order to meet the United States Golf Association (“U.S.G.A.”) specifications, the golf ball must be spherical in shape, have equal aerodynamic properties and equal moments of inertia about any axis through its center. The ball must have a minimum diameter of 1.68 inches (4.267 centimeters), a maximum weight ...

AI Technical Summary

Benefits of technology

The present invention provides a golf ball with improved performance characteristics by minimizing the density in the center of the ball while maximizing the density away from the center and near the cover or outer edge of the ball. This allows the ball to have both low spin for maximum distance and a "bite" when landing on a surface such as a putting green. The invention also provides a golf ball with an improved moment of inertia without adversely affecting the rebound characteristics. The golf ball has a hard hollow sphere and an outer layer surrounding the sphere, with a second layer placed between the sphere and outer layer so that the second layer surrounds the sphere and is surrounded by the cover. The second layer consists of a compressible material, such as polybutadiene, and a more durable material, such as an ionomer. The invention concentrates the weight and density away from the center of the ball to improve its performance characteristics while maintaining optimum rebound characteristics.

Problems solved by technology

More recent golf ball designs have, however, focused on solid, multi-piece golf balls wherein the density of the ball is not uniform throughout.

While others have attempted to provide golf ball designs so that the moment of inertia and the spin rate can be controlled by selection of the weight or density and size of the materials comprising the golf ball, these designs are limited in the degree to which the higher density can be concentrated close to the cover or outer edge of the golf ball.

Additionally, the use of fillers such as zinc oxide, barium sulfate, calcium carbonate, and other non-polymer compounds to increase the weight distribution of the ball toward the outer core adversely affect other important performance characteristics such as rebound.

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