Golf ball
AssigneeSRI Sports Limited
InventorsKazuya KAMINO, Keiji Ohama, Hirotaka Nakamura
Life of this patent
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Abstract
A golf ball 2 includes a core 4, an envelope layer 6 positioned outside the core 4, a mid layer 8 positioned outside the envelope layer 6, and a cover 10 positioned outside the mid layer 8. The core 4 includes a spherical center 12 and a core outer layer 14 positioned outside the center 12. The center 12 has a diameter of 1 mm or greater and 15 mm or less. The difference (H4−H3) between the JIS-C hardness H4 of the core 4 at its surface and the JIS-C hardness H3 of the core outer layer 14 at its innermost portion is equal to or greater than 10. The cover 10 has a Shore D hardness H7 less than 40. The Shore D hardnesses H5, H6 and H7 of the envelope layer 6, the mid layer 8, and the cover 10 satisfy that H5>H6≧H7.
Claims20
A golf ball comprising a core, an envelope layer positioned outside the core, a mid layer positioned outside the envelope layer, and a cover positioned outside the mid layer, wherein:
- the core includes a center and a core outer layer positioned outside the center;
- the center has a diameter of 1 mm or greater and 15 mm or less;
- a difference (H4−H3) between a JIS-C hardness H4 of the core at its surface and a JIS-C hardness H3 of the core outer layer at its innermost portion is equal to or greater than 10;
- the cover has a Shore D hardness H7 less than 40;
- and
- a Shore D hardness H5 of the envelope layer, a Shore D hardness H6 of the mid layer, and a Shore D hardness H7 of the cover satisfy the following mathematical formula (I).
- H5>H6≧H7 (I)
Dependencies are inferred from the claim text.