Patent ID: 11911665
Assignee: BRIDGESTONE SPORTS CO., LTD.
Field: Furniture, games (Other fields)
Classification: CPC A | IPC A

Claim 9:
10. A golf ball comprising a core and a cover, which cover has a plurality of dimples on a surface thereof, wherein the cover is formed primarily of polyurethane and the dimples thereon have a volume occupancy ratio VR within the range of 0.80 to 0.92%, the ball has a diameter of at least 42.9 mm and, in an impact test carried out by hitting the ball with a driver at a head speed of 40 m/s, the sum t1+t2 of the time t1 required from initial contact by the driver with the ball for deformation of the ball to reach a maximum and the time t2 required from the state of maximum ball deformation for the ball and the driver to separate is 660 μsec or less, wherein the core has a diameter of at least 37.0 mm and a hardness profile in which, letting Cc be the Shore C hardness at a center of the core, Cs be the Shore C hardness at a surface of the core, Cm be the Shore C hardness at a midpoint M between the core center and the core surface, Cm−2, Cm−4, Cm−6 and Cm−8 be the respective Shore C hardnesses at positions 2 mm, 4 mm, 6 mm and 8 mm inward from the midpoint M and Cm+2, Cm+4 and Cm+6 be the respective Shore C hardnesses at positions 2 mm, 4 mm and 6 mm outward from the midpoint M, and defining surface areas X and A to F as follows
surface area X: ½×2×(Cm−6-Cm−8)
surface area A: ½×2×(Cm−4-Cm−6)
surface area B: ½×2×(Cm−2-Cm−4)
surface area C: ½×2×(Cm-Cm−2)
surface area D: ½×2×(Cm+2-Cm)
surface area E: ½×2×(Cm+4-Cm+2)
surface area F: ½×2×(Cm+6-Cm+4),
the core satisfies the condition:

(surface area D+surface area E+surface area F)−(surface area A+surface area B+surface area C)>0.