Multi-layer golf ball construction

Abstract

Disclosed herein is a six piece golf ball having a core, an inner mantle layer, an intermediate mantle layer, an outer mantle layer, an inner cover layer, and an outer cover layer.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of U.S. application Ser. No. 13 / 719,077, filed Dec. 18, 2012, that claims the benefit of U.S. Provisional Application No. 61 / 580,120, filed Dec. 23, 2011, both of which are incorporated herein by reference in their entireties.BACKGROUND OF THE INVENTION[0002]The present invention relates to sports equipment in general and more particularly to golf balls. So called “multi-layer” golf balls generally include at least three “pieces”—a central core and at least two layers surrounding the core. A multi-layer ball can offer several advantages and disadvantages. However, the specific advantages and disadvantages potentially provided by a specific contemplated design are unpredictable due to the complex nature of the physical interaction between the various materials used in the core and the layers.SUMMARY[0003]Disclosed herein is a six piece golf ball having a core having a center and an outer surface a...

AI Technical Summary

Benefits of technology

[0008]Accordingly, a variety of golf ball constructions have been developed in an attempt to provide spin rates and a feel approaching those of balata covered balls, while also providing a golf ball with a higher durability and overall distance. This has resulted in the emergence of balls, which have a solid rubber core, a cover, and one or more so called intermediate layers, as well as the application of new materials to each of these components.

[0010]In addition, recent changes to the allowable groove configurations in iron golf clubs by the USGA has resulted in the newer iron grooves imparting less spin to a given golf ball by a factor of 10-40% depending on the type of shot and club. All other things being equal one method of compensating for this loss of spin on wedge shots is to increase the capacity of the ball to generate spin on impact. Typically this has been accomplished by making the outer cover layer softer (as in the balata covers) and inserting an additional harder inner cover layer immediately below the soft outer cover layer which on impact causes the soft outer cover layer to be pinched between the hard club face and hard inner cover layer, generating even more spin. However although this combination of a soft outer cover and a harder inner cover results in additional spin on wedge shots, it also results in increased spin on the ball when struck by a driver. An increase in the amount of side spin can, depending on its direction, cause the ball trajectory to veer left (hook) or right (slice). One method to compensate for this is to lower the core compression which reduces the spin rate on a driver shot (the high velocity of the impact causing the core to compress) but this has a lower effect on the wedge spin rate as the lower velocity impact of a wedge shot does not compress the golf ball core to the same degree on impact as a higher velocity driver shot.

[0011]However, the degree to which the core compression can be lowered to compensate for the increase in spin generated by the combination of a soft outer cover and hard inner cover layer is in turn determined by the durability of the hard inner cover layer which, in the absence of a hard core to support it will, in some ball constructions, have a tendency to crack or fail on a high velocity driver impact. In addition, there still remains the problem of imparting too much spin to mid to low iron shots which in turn results in loss of distance. Thus there remains a need for ball constructions which are able to impart high spin on wedge shots while minimizing the spin generated on driver shots and which also have sufficient performance not just in terms of durability but also minimizing spin and thus maximizing distance on long iron and mid iron shots. As in all golf shots, it would also be highly desirable if the new ball constructions are also able to deliver improved feel transmitted to the golfer when he impacts the ball, which is in turn obtained by controlling the sound performance of the golf ball impact, both in terms of the frequency of the impact sound in Hz, and the sound pressure level generated on impact in decibels.

[0012]We have now found that a six-piece ball construction of the present invention having a combination of a soft core with a compression of less than 35 PGA combined with a hard inner cover layer (having a hardness of at least 65 Shore D, and a flexural modulus of at least 65 kpsi) and a soft outer cover layer having a hardness of 50-60 Shore D and a flex modulus of 5-15 kpsi with three additional mantle layers of the required physical properties and materials of construction between the core and hard inner cover layer (the inner mantle, intermediate mantle and outer mantle layers respectively) results in a golf ball with the required durability and high wedge spin, low driver spin, low mid iron spin and the required sound and hence feel performance.SUMMARY

Problems solved by technology

One-piece balls are inexpensive and very durable, but typically do not provide great distance because of relatively high spin and low velocity.

However balata-covered balls, although exhibiting high spin and soft feel, were often deficient in terms of the durability of the cover which had a propensity to shear and also the velocity of the ball when it leaves the club face (which in turn affects the distance the ball travels).

However although this combination of a soft outer cover and a harder inner cover results in additional spin on wedge shots, it also results in increased spin on the ball when struck by a driver.

However, the degree to which the core compression can be lowered to compensate for the increase in spin generated by the combination of a soft outer cover and hard inner cover layer is in turn determined by the durability of the hard inner cover layer which, in the absence of a hard core to support it will, in some ball constructions, have a tendency to crack or fail on a high velocity driver impact.

In addition, there still remains the problem of imparting too much spin to mid to low iron shots which in turn results in loss of distance.

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