Games using tangible projectile – Golf – Ball
Reexamination Certificate
2001-08-06
2003-10-21
Graham, Mark S. (Department: 3711)
Games using tangible projectile
Golf
Ball
Reexamination Certificate
active
06634962
ABSTRACT:
FIELD OF THE INVENTION
This invention generally relates to golf balls, and more specifically, to a multi-component golf ball. In particular, this invention relates to a golf ball having a core, at least one cover layer, and one or more interior mantle layers disposed between the core and cover layer. Relatively small foam granules are dispersed throughout one or more of the mantle layers, the core, or both. The multi-component golf balls of the present invention, having such a configuration and using such foam granules, have been found to provide the distance and durability characteristics approaching that of a conventional two-piece ball while also providing the “click and feel” of a conventional three-piece or “wound” ball.
BACKGROUND OF THE INVENTION
Conventional golf balls can be divided into two general types or groups, two-piece balls or wound balls (also known as three-piece balls). The difference in play characteristics resulting from these different types of constructions can be quite significant.
Balls having a two-piece construction are generally most popular with the average recreational golfer because they provide a very durable ball while also providing maximum distance. Two-piece balls are made with a single solid core, usually made of a crosslinked rubber, which is encased by a cover material. Typically, the solid core is made of polybutadiene which is chemically crosslinked tough, cut-proof blended cover. The cover is generally material such as SURLYN®, which is a trademark for an ionomer resin produced by DuPont. The combination of the core and cover materials provide a “hard” ball that is virtually indestructible by golfers. Further, such a combination imparts a high initial velocity to the ball which results in improved distance. Because these materials are very rigid, two piece balls have a hard “feel” when struck with a club. Likewise, due to their hardness, these balls have a relatively low spin rate which makes them difficult to control, particularly in shorter approach shots. However, as golf ball manufacturers continue to improve the spin and feel characteristics of the two-piece ball, it is likely that the two-piece ball will continue to grow in popularity.
But, at the present time, the wound ball remains the preferred ball of the more advanced players due to its superior spin and feel characteristics. Wound balls typically have either a solid rubber or liquid center core around which many yards of a stretched elastic thread or yarn are wound. The wound core is then covered with a durable cover material such as a SURLYN® or similar material or a softer cover such as Balata. Wound balls are generally softer and provide more spin, which enables a skilled golfer to have more control over the ball's flight. However, wound higher spinning balls typically have a shorter distance as compared to a two-piece ball. Moreover, as a result of their more complex structure, wound balls generally require a longer time to manufacture and are more expensive to produce than a two-piece ball.
Consequently, a need exists for an improved ball which provides the “click and feel” of a wound ball, while also providing the relative ease of manufacturing, durability and distance of a two-piece ball.
DESCRIPTION OF THE PRIOR ART
Several patents have been issued which are directed toward modifying the properties of a conventional two-piece ball by altering the typical single-layer core and single cover layer construction to provide a multi-layer core. The developments disclosed in the prior art patents are directed toward improving a variety of golf ball characteristics.
Several patents are directed toward improving the carry distance of ball having improved rebound characteristics in order to increase its flight distance. This golf ball has a center portion and an outer layer formed from a rubber composition, preferably having a base rubber of polybutadiene, wherein the outer layer further contains a gravity filler such as tungsten or tungsten carbide so as to impart a higher specific gravity to the outer layer than that of the inner layer. The difference in specific gravity of the layers should be 0.15-0.8 for small balls and 0.15-0.45 for large balls. Preferably, the outer layer is harder than the center portion.
U.S. Pat. No. 5,184,828 relates to a solid three-piece golf ball having improved rebound characteristics and carry distance while maintaining an adequate spin rate. These characteristics are obtained by controlling the size of the inner core and outer layer as well as the specific gravity and hardness. The core and mantle layers are made from a rubber compound such as polybutadiene, and have a Shore D hardness of 30-62 and 30-56, respectively. The key to obtaining the desired rebound characteristics is that the maximum hardness (42-62) must be located at the interface between the core and the mantle and the hardness must then decrease both inwardly and outwardly.
U.S. Pat. No. 4,714,253 is also directed toward a three-piece golf ball having an excellent rebound coefficient. This golf ball has a core with a Shore C hardness of 57-80 in its center, but not more than 83 at a distance between 5-10 mm from its center and outer layer with a Shore C hardness of 70-83.
Additionally, there are a number of patents also directed toward improving the spin, click or feel of solid balls while maintaining the distance provided by the solid construction. A variety of approaches to manipulating the core construction are described in the art. For example, U.S. Pat. No. 5,072,944 discloses a three-piece solid golf ball having a center and outer layer which are prepared from a rubber composition, preferably having a base rubber of polybutadiene. It is desirable that the center core is softer than the outer layer, each having a hardness (Shore C) of 25-50 and 70-90, respectively.
U.S. Pat. No. 4,625,964 relates to a solid golf ball having a polybutadiene rubber core of a diameter not more than 32 mm, and a polybutadiene rubber intermediate layer having a specific gravity of lower than that
U.S. Pat. No. 4,650,193 is directed toward a solid golf ball having a core comprising a central portion and an integral outer layer. Preferably, the core is a curable elastomer such as polybutadiene which is treated with a cure altering agent to soften an outer layer of the core, thereby producing a central layer with a hardness (Shore C) of greater than 75 and an outer layer with a hardness (Shore A) of less than 80.
U.S. Pat. No. 4,848,770 discloses a non-wound, three-piece golf ball which includes a core of a highly filled synthetic rubber or polymeric material, an intermediate mantle of an unfilled synthetic rubber and a cover. The core and intermediate mantle have a hardness of between 50-95.
U.S. Pat. No. 5,002,281 is directed toward a three-piece solid golf ball which has an inner core having a hardness of 25-70 (Shore C), an outer shell having a hardness of 80-95 (Shore C) and a cover. Further, the specific gravity of the inner core must be greater than 1.0, but less than or equal to that of the outer shell, which must be less than 1.3.
U.S. Pat. No. 5,253,871 concerns a golf ball having a three-piece structure comprising an elastomer core, an intermediate layer of a thermoplastic material containing at least 10% of ether block copolymer, preferably blended with an ionomer and a thermoplastic cover.
Further, there are also several patents which are directed to golf balls having multiple cover layers. For example, U.S. Pat. No. 4,431,193 relates to a golf ball having a multi-layer cover wherein the inner layer is a hard, high flexural modulus ionomer resin and the outer layer is a soft, low flexural modulus ionomer resin, and wherein either or both layers may comprise a foamed ionomer resin.
U.S. Pat. No. 5,314,187 also relates to golf balls having a multiple layer cover, wherein the outer layer is molded over the inner layer and comprises a blend of balata and an elastomer and the inner layer is an ionomer resin.
U.S. Pat. No. 4,919,434 is directed toward a golf ball having a cover which
Gorden Raeann
Graham Mark S.
The Top-Flite Golf Company
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