Golf ball incorporating an innermost hollow portion

Abstract

Golf ball incorporating: spherical or aspherical innermost hollow portion; shell layer, one or more outer core layers, and at least one cover layer. Shell layer has outer surface hardness greater than inner surface hardness by up to about 7 Shore C to define first hardness gradient. Outer core layer has a second hardness gradient. A shell layer surrounding a spherical hollow portion may have an inner surface with a non-uniform contour defining a phantom spherical circumference of the innermost spherical hollow portion at symmetrically spaced locations about the golf ball's geometric center. In golf balls including a spherical or aspherical innermost hollow portions, the outer surface can have non-uniform contour bordering and defining a contour of a second inner surface of outer core layer. The outer surface hardness and a second inner surface hardness of second inner surface differ and alternate symmetrically and circumferentially about the shell layer inner surface.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application is a continuation-in-part of U.S. patent application Ser. No. 14 / 959,190, filed on Dec. 4, 2015, and also a continuation-in-part of U.S. patent application Ser. Nos. 13 / 736,993, 13 / 736,997, 13 / 737,026, and 13 / 737,041, each filed on Jan. 9, 2013, the entire disclosures of which are hereby incorporated herein by reference in their entireties.FIELD OF THE INVENTION[0002]This invention relates generally to hollow core golf ball constructions that target desirable aerodynamic and / or inertial properties and feel without sacrificing durability.BACKGROUND OF THE INVENTION[0003]In recent years, virtually all golf balls are of a solid construction, typically including a solid core encased by a cover, both of which can have multiple layers, such as a dual core having a solid center and an outer core layer, or a multi-layer cover having an inner and outer cover layer. Golf ball cores are often formed at least in part from a th...

AI Technical Summary

Benefits of technology

The patent is about an improved golf ball construction with a hollow core. The design has a uniform hardness distribution and adhesion between layers, creating a smooth transition between the innermost hollow part and the shell layer. The hardness gradient also extends to the outer core layer for an even better feel and performance. The patent allows for the construction of golf balls with the desired playing characteristics and feel using a spherical or aspherical hollow core.

Problems solved by technology

However, while many prior commercially available golf balls have been constructed with non-solid centers such as liquid centers, very few golf balls having hollow centers have ever been pursued.

One reason is that it has been difficult to implement hollow cores in golf ball constructions and target / improve aerodynamic and / or inertial properties and achieve desired feel without sacrificing durability.

One problem encountered with the prior golf balls incorporating inserts to create an aspherical hollow space within the core was that poor bonding / adhesion sometimes occurred between the insert and an adjacent surrounding layer, resulting in separation of outer layer from the insert when the golf ball was struck by a club face.

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