Games using tangible projectile – Golf – Ball
Reexamination Certificate
2003-01-21
2004-04-27
Vidovich, Gregory (Department: 3711)
Games using tangible projectile
Golf
Ball
Reexamination Certificate
active
06726577
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to golf balls, and more specifically, to one piece golf balls of unitary molded construction that are suitable for shorter and “off-course” playing, as well as to methods of manufacturing relating thereto.
BACKGROUND OF THE INVENTION
Golf balls have traditionally been categorized into three different groups; namely, (1) one piece golf balls of unitary molded construction, (2) multi-piece golf balls (i.e., two or more concentric pieces) of layered construction, and (3) wound golf balls (i.e., core consists of a wound elastic thread) of layered construction. The physical and structural differences among these three distinct groups of golf ball construction are very significant; as are the differences in their play characteristics.
The wound-golf ball (frequently referred to as a three piece golf ball), for example, is generally made from a vulcanized rubber thread wound under tension around a solid or semi-solid center to form a wound core. The wound core is then encased in a single or multi-layer covering of one or more tough protective materials. Similarly, the multi-piece golf ball is generally made from a solid resilient core having single or multiple cover layers thereon. In both types of layered golf ball, the materials of the inner layers tend to vary significantly, while the material of the outermost cover layer is most commonly either balata or SURLYN (E.I. duPont de Nemours and Company, United States). In this regard, it is generally believed that SURLYN provides a stronger, more durable cover, whereas balata provides a softer cover that offers a bit more spin control. Regardless of the cover layer material, golf balls of layered construction have evolved significantly over the years to achieve, among other things, better flight and distance characteristics (innovations made possible, in part, by the development of new synthetic polymers and other specialty chemicals). Indeed, searchable databases maintained by the U.S. Patent and Trademark Office reveal that several thousand U.S. patents have thus far issued on inventions relating to golf balls of layered construction.
In contradistinction, one piece golf balls of unitary molded construction are typically formed from a homogeneous mass of a moldable synthetic material. As such, golf balls of this type of construction generally possess a homogeneous composition (i.e., the composition is substantially uniform between the interior and exterior of each ball); and there is generally no separate outer protective covering. One piece golf balls of unitary molded construction are known in the art and have been described over the years in the patent literature. Exemplary in this regard are U.S. Pat. Nos. 3,238,156, 3,239,228, 3,241,834, 3,313,545; 3,373,123, 3,384,612, 3,421,766, 3,438,933, 3,452,986, 3992,014, 4,165,877, 4,266,772, 5,082,285, 5,330,837, and 6,277,924. In general unitary golf balls described in these patents are suitable only for practice, and not competitive play. More importantly, however, is that these patents reveal that relatively few technological innovations have been made over the years with respect to one piece golf balls, especially with respect to the use of newly developed synthetic polymers and other specialty chemicals.
Specifically, and although numerous attempts have been made to manufacture one piece golf balls of unitary molded construction, a one piece golf ball has not yet been developed that is both relatively lightweight and able to “pop” off a club face like that of a layered construction golf ball. In addition, there has not yet been developed a one piece golf ball that has great elasticity and bouncing characteristics and that is suitable for shorter or off-course playing. Accordingly, there is still a need in the art for novel golf balls of unitary molded construction, as well as to methods of manufacturing relating thereto. The present invention fulfills these needs and provides for further related advantages.
SUMMARY OF THE INVENTION
In brief, the present invention relates generally to golf balls, and more specifically, to one piece golf balls of unitary molded construction suitable for shorter (e.g., par 3 courses) and “off-course” playing, as well as to methods of manufacturing relating thereto. In one embodiment, the present invention is directed to a golf ball of unitary molded construction, wherein the golf ball is foamed from a composition that comprises an ethylene-vinyl acetate copolymer, a thermoplastic elastomer, and a blowing agent, and wherein the golf ball has (i) a diameter that ranges from about 1.6 to about 1.75 inches, (ii) a weight that ranges from about 10 to about 15 grams, and (iii) a coefficient of restitution value that ranges from about 0.33 to about 0.42. In another embodiment, the present invention is directed to a golf ball of unitary molded construction, wherein the golf ball is foamed from a composition comprising: a major amount by weight of an ethylene-vinyl acetate copolymer; a minor amount by weight of a thermoplastic elastomer material, wherein the thermoplastic elastomer material is one or more of (i) a thermoplastic elastomer based on a dynamically vulcanized elastomer-thermoplastic blend, (ii) a styrene tri-block copolymer thermoplastic elastomer, and (iii) an ethylene-&agr;-olefin copolymer thermoplastic elastomer; and a blowing agent.
DETAILED DESCRIPTION OF THE INVENTION
As noted above, the present invention relates generally to golf balls, and more specifically, to one piece golf balls of unitary molded construction suitable for shorter and “off-course” playing, as well as to methods of manufacturing relating thereto. In some embodiments, the golf balls of the present invention comprise a thermoplastic elastomer material admixed together with an ethylene-vinyl acetate copolymer. More specifically, it has been discovered that unitary golf balls made from a composition comprising (i) one or more thermoplastic elastomer materials, (ii) an ethylene-vinyl acetate copolymer, and (iii) other optional fillers and/or processing additives, have highly desirable properties and characteristics which make them highly desirable for shorter and “off-course” playing. For example, it has been surprisingly discovered that, among other things, golf balls made from such novel compositions are highly suitable for “off-course” playing because they are highly elastic (and thus have a good “spring” feel when hit off a club face), durable, and travel only about one-third to about one-half as far as a conventional golf ball of layered construction. In addition, the unitary golf balls of the present invention are, in general, relatively less expensive to produce than many other types of practice or off-course golf balls.
In some exemplary embodiments, the unitary golf balls of the present invention are made of a foamed thermoplastic elastomer/ethylene-vinyl acetate copolymer admixture that has been molded into the shape of a standard sized golf ball (i.e., golf ball having a diameter of about 1.68 inches). The thermoplastic elastomer component of such an admixture is preferably a styrene block copolymer thermoplastic elastomer, and the ethylene-vinyl acetate copolymer preferably has a vinyl acetate content ranging from about 15% to about 18%. The weight of each such exemplary golf ball generally ranges from about 10 to about 25 grams (and preferably from about 12 to about 16 grams); whereas the “coefficient of restitution” (COR) generally ranges from about 0.33 to about 0.42 (and preferably from about 0.36 to about 0.39). As is appreciated by those skilled in the art, the “coefficient of restitution” is simply a measure of the ratio of the relative velocity of an elastic sphere immediately before and after a direct impact. The “coefficient of restitution” can vary from zero to one, with one being equivalent to a completely elastic collision and zero being equivalent to a completely inelastic collision.
Because many embodiments of the present invention encompass a wide range of possible polymer compositions—particu
Almost Golf, Inc.
Hunter, Jr. Alvin A.
Loop Thomas E.
Vidovich Gregory
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