Golf ball
AssigneeDunlop Sports Co. Ltd.
InventorsKazuhiko Isogawa, Yoshiko Matsuyama, Kosuke Tachibana
Life of this patent
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Abstract
A golf ball 2 includes a core 4, a mid layer 6, a reinforcing layer 8, and a cover 10. A hardness Hm of the mid layer 6 is greater than a hardness Hc of the cover 10. A difference (Hm−Hc) is greater than 28. A hardness Hs2 at a surface of a sphere consisting of the core 4 and the mid layer 6 is greater than a hardness Hs3 at a surface of the golf ball 2. A difference (Hs2−Hs3) is less than 5. A thickness Tm of the mid layer 6 is larger than a thickness Tc of the cover 10. A ratio (Tm/Tc) is greater than 3.0 and less than 5.0. A diameter of the core 4 is equal to or greater than 38.2 mm. The hardness Hc of the cover 10 is equal to or less than 37.
Claims11
A golf ball comprising a core, a mid layer positioned outside the core, a reinforcing layer positioned outside the mid layer, and a cover positioned outside the reinforcing layer, wherein
- the mid layer material Shore D hardness Hm is greater than the cover material Shore D hardness Hc by an amount greater than 28,
- the surface of a sphere including the core and the mid layer has a Shore D hardness Hs2 that is greater than the golf ball surface Shore D hardness Hs3 by an amount less than 5,
- the mid layer thickness Tm is larger than the cover thickness Tc, and a ratio (Tm/Tc) of both thicknesses is greater than 3.0 and less than 5.0,
- a diameter of the core is equal to or greater than 38.2 mm,
- the hardness He is equal to or less than 37,
- the reinforcing layer is formed from an adhesive, and
- a gel fraction of the adhesive is equal to or greater than 40% but equal to or less than 80%.
Dependencies are inferred from the claim text.