Games using tangible projectile – Golf – Ball
Reexamination Certificate
2002-01-03
2003-10-14
Wong, Steven (Department: 3711)
Games using tangible projectile
Golf
Ball
C473S379000
Reexamination Certificate
active
06632148
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a golf ball exhibiting a very soft hitting feel, an excellent durability, a low spin rate and a high hitting angle, and an increased carry due to a high resilience.
Golf balls have been variously improved to meet various needs of players, and the present applicant has proposed various excellent golf balls.
For example, Japanese Patent Laid-open No. Hei 9-313643 has disclosed an all-around golf ball having an excellent carrying performance and a high durability, giving a soft hitting feel, and having a good controllability. Japanese Patent Laid-open No. Hei 10-305114 has disclosed a golf ball exhibiting a significantly increased carry and giving a good hitting feel. Japanese Patent Laid-open No. Hei 11-57067 has disclosed a golf ball, which is specified mainly in a relationship between hardnesses of a cover and an intermediate layer and dimples so as to eliminate blow away or drop of the trajectory and hence to increase the carry. Japanese Patent Laid-open No. Hei 11-114094 has disclosed a golf ball, which is specified mainly in a relationship between a deformed amount of a solid core, and thicknesses and hardnesses of a cover and an intermediate layer so as to improve the trajectory upon driver shot and thereby increase the carry, obtain a suitable spin performance upon approach shot, enhance the controllability, and improve the hitting feel and the durability. Japanese Patent Laid-open No. 2000-225209 has disclosed a golf ball, which has a ball structure specified in a relationship among a deformed amount of a solid core, hardnesses of a cover and an intermediate layer, and dimples so as to improve the hitting feel, the durability, and the resilience performance while enhancing the carrying performance, and hence to exhibit excellent performances as a whole.
These golf balls, each of which gives an excellent hitting feel and has a good carrying performance, can desirably meet various needs of players, such as techniques of players and applications of the balls; however, the player's demands against golf balls have come to be further increased, and therefore, it is expected to develop a golf ball with further improved performances.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a golf ball capable of exhibiting a very soft hitting feel, an excellent durability, a low spin rate and a high hitting angle, and an increased carry due to a high resilience.
To achieve the above object, the present inventor has studied a golf ball of a type including a solid core, an intermediate layer, and a cover in a surface of which a plurality of dimples are formed, and found that the golf ball having the following features (1) to (6) can exhibit a very soft hitting feel, an excellent durability, a low spin rate and a high hitting angle, and an increased carry due to a high resilience.
(1) The solid core has a center JIS-C hardness in a range of 50 to 70 and a surface JIS-C hardness in a range of 60 to 80, and has a diameter in a range of 35 to 40 mm.
(2) The intermediate layer is made from a material containing an ionomer resin as a main component, and has a JIS-C hardness in a range of 70 to 85 and a thickness in a range of 0.5 to 2 mm.
(3) The cover is made from a material containing an ionomer resin as a main component, and has a JIS-C hardness in a range of 85 or more and a thickness in a range of 0.5 to 2 mm.
(4) A difference in JIS-C hardness between the intermediate layer and the surface of the solid core (|intermediate layer hardness−solid core surface hardness|) is in a range of 15 or less.
(5) A different in JIS-C hardness between the cover and the intermediate layer (|cover hardness−intermediate layer hardness|) is in a range of 10 or more.
(6) The hardnesses of the solid core, the intermediate layer, and the cover satisfy a relationship of (hardness gradient from intermediate layer to cover)/(hardness gradient from core center to intermediate layer)≧6.
(7) The dimples are arranged in such a manner that there is no great circle line not crossing any one of the dimples.
To be more specific, since both an adhesiveness between the core and the intermediate layer and an adhesiveness between the intermediate layer and the cover are improved, the durability can be enhanced although the core is very soft. Since a dimple arrangement (so-called seamless structure) with no great circle line not crossing any of the dimples is adopted, partial unevenness of the dimples can be eliminated to significantly reduce a variation in carry. Further, there can be realized a ball structure capable of suppressing a side spin, thereby preventing the ball from being flied along a curved trajectory, by combination of the seamless structure with the ball configuration improved to reduce the spin rate. On the basis of the above knowledge, the present invention has been accomplished.
According to an aspect of the present invention, there is provided a golf ball including a solid core, an intermediate layer, and a cover in a surface of which a plurality of dimples are formed, wherein the solid core has a center JIS-C hardness in a range of 50 to 70 and a surface JIS-C hardness in a range of 60 to 80, and has a diameter in a range of 35 to 40 mm; the intermediate layer is made from a material containing an ionomer resin as a main component, and has a JIS-C hardness in a range of 70 to 85 and a thickness in a range of 0.5 to 2 mm; the cover is made from a material containing an ionomer resin as a main component, and has a JIS-C hardness in a range of 85 or more and a thickness in a range of 0.5 to 2 mm; a difference in JIS-C hardness between the intermediate layer and the surface of the solid core (|intermediate layer hardness−solid core surface hardness|) is in a range of 15 or less; a different in JIS-C hardness between the cover and the intermediate layer (|cover hardness−intermediate layer hardness|) is in a range of 10 or more; the hardnesses of the solid core, the intermediate layer, and the cover satisfy a relationship of (hardness gradient from intermediate layer to cover)/(hardness gradient from core center to intermediate layer)≧6; and the dimples are arranged in such a manner that there is no great circle line not crossing any one of the dimples.
The JIS-C hardnesses of the surface of the solid core, the intermediate layer, and the cover preferably satisfy a relationship of (hardness of surface of solid core<hardness of intermediate layer<hardness of cover).
The intermediate layer is preferably made from a material containing, as a main component, a mixture of 50 to 100 mass % of an ionomer resin and 0 to 50 mass % of a thermoplastic elastomer having a crystalline polyethylene block.
The number of kinds of the dimples in terms of shape is preferably in a range of two or more, and the total number of the dimples is in a range of 360 to 460 pieces.
A dimple volume occupying ratio VR (%) is preferably in a range of 0.60 to 1.00%, the dimple volume occupying ratio being defined as a ratio of a total of dimple space volumes under plane surfaces surrounded by edge portions of the dimples to a volume of a virtual ball being the same as the golf ball except that the virtual ball has no dimples, and a dimple surface occupying ratio SR (%) is preferably in a range of 70 to 85%, the dimple surface occupying ratio being defined as a ratio of a total of areas occupied by dimple forming portions to a surface area of the virtual ball.
The arrangement of the dimples is preferably a regular polyhedral arrangement.
The arrangement of the dimples is preferably a regular icosahedral arrangement.
REFERENCES:
patent: 5249804 (1993-10-01), Sanchez
patent: 5830085 (1998-11-01), Higuchi et al.
patent: 5902193 (1999-05-01), Shimosaka et al.
patent: 2 355 939 (2001-05-01), None
patent: 2 359 998 (2001-09-01), None
patent: 9-313643 (1997-12-01), None
patent: 10-305114 (1998-11-01), None
patent: 11-57067 (1999-03-01), None
patent: 11-114094 (1999-04-
Hayashi Junji
Shimizu Yasumasa
Yamagishi Hisashi
Bridgestone Sports Co. Ltd.
Gorden Raeann
Sughrue & Mion, PLLC
Wong Steven
LandOfFree
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