Patent ID: 8663028

Claim:
A golf club head comprising a head body having a face for hitting a ball on a front side of the head body and at least one recess portion in an outer surface of the head body excluding said face, the recess portion having a bottom surface and a sidewall surface extending from the bottom surface to said outer surface of the head body, and at least one vibration absorbing member made of a viscoelastic material and inserted in said at least one recess portion, wherein the head body is provided on its back side with a cavity and a backward protruding portion extending annularly around the cavity, the backward protruding portion is provided on the sole side of the cavity with said at least one recess portion so as to open in the back surface thereof and so that the depth direction of the recess portion substantially conforms to the front-back direction of the head, the vibration absorbing member inserted in the recess portion has a front end fixed to the bottom surface of the recess portion, a rear end located at a position corresponding to said outer surface of the head body in the backward protruding portion, and a side surface extending from the front end to the rear end, the side surface comprises a fixing portion extending for a small distance D 1 from the front end toward the rear end and coming into contact with the sidewall surface of the recess portion and a non-fixing portion extending from the fixing portion to the rear end without coming into contact with the sidewall surface of the recess portion to define a constant space in a range of from 0.1 to 3 mm between the sidewall surface and the non-fixing portion of the side surface, the constant space is formed all around the non-fixing portion of the side surface and the rear end of the vibration absorbing member is exposed to the outside of the club head so as to form a part of the outer surface of the golf club head, whereby said constant space of 0.1 to 3 mm is opened in the outer surface of the golf club head so as to surround the rear end of the vibration absorbing member, wherein said head body is an iron-type, said at least one recess portion includes a toe side recess portion formed on a toe side of said head and a heel side recess portion formed on a heel side of said head, said at least one vibration absorbing member includes a toe side vibration absorbing member disposed in said toe side recess portion and a heel side vibration absorbing member disposed in said heel side recess portion, said toe side vibration absorbing member has a center of gravity on a toe side with respect to a vertical plane VP which passes through a sweet spot normal to said face, and said heel side vibration absorbing member has a center of gravity on a heel side with respect to said vertical plane VP.