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 in part 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, each of which are hereby incorporated by reference thereto.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 hard spherical core or layer with improved characteristics. BACKGROUND OF THE INVENTION [0003] In order to meet United States Golf Association (“U.S.G.A.”) specifications, a golf ball must meet certain test criteria relating to weight, size, initial velocity, overall distance (carry and roll), and spherical symmetry. In general, a golf ball must not weigh m...

AI Technical Summary

Benefits of technology

[0009] The present invention also provides a method of constructing a metal sphere core with controlled stiffness for use in a modern golf ball, where the metal sphere core has an outer surface and an inner surface, together defining a core thickness. In one embodiment, the method includes forming at least one groove or any other type of indentation in the outer core surface for controlling the stiffness of the metal sphere core. In another embodiment, the method includes forming at least one groove in the inner core surface for controlling the stiffness of the metal sphere core. In another embodiment, the method includes forming at least one groove in the outer core surface and at least one groove in the inner core surface, for controlling the stiffness of the metal sphere core.

[0010] The golf ball of the present invention has several advantages that provide a golf ball having a hollow hard sphere core in which the stiffness of the core may be controlled, while maintaining the high overall moment of inertia for the golf ball. The golf ball includes a cover layer and a hard sphere core that has an outer core surface and an inner core surface where the outer core surface has at least one, and preferably a plurality of, regularly spaced horizontal grooves and a plurality of regularly spaced vertical grooves that serves to decrease the stiffness of the hollow metal sphere core. The grooves are regularly spaced in order to maintain a golf ball that will perform similarly about any axis of rotation, such that the golf ball will conform to the current U.S.G.A. golf ball standard. This results in a hollow metal sphere core for a golf ball in which the stiffness may be controlled and the effect on the high moment of inertia of the ball may be minimized.

Problems solved by technology

Many, for instance, use fillers to increase the weight distribution of the golf ball towards the cover of the ball, which tend to adversely affect the ball's performance, such as with respect to rebound.

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