US Patent 7775904 Wood-type golf club head

A wood-type golf club head has a hollow structure comprising a face portion having a back surface and a front surface defining a club face for striking a ball, a crown portion, a sole portion, and a side portion between the crown portion and sole portion. The hollow structure is provided with a hollow and a solid part. The solid part extends forward from the backmost point of the club head by a distance of from 0.08 to 0.20 times the maximum size of the club head in the back-and-forth direction, the hollow extends between the front surface of the solid part and the back surface of the face portion. The main frame of the hollow structure integrally includes the solid part.