Abstract: A golf head club has a high moment of inertia and thus produces a pleasing hitting sound. A metallic golf club head 1 having a hollow space therein includes a face member 30 provided with a face part 31, and a body member 10 provided with a sole part 11, a crown part 12, a side part 13, and ribs 20. The hollow space is defined by the inner surfaces of the face part 31, the sole part 11, the crown part 12, and the side part 13, and the wall surfaces of the ribs. The ribs 20 extend from the inner surface of the sole part 11 to the inner surface of the crown part 12, and the body member 10 is molded integrally by casting.

Abstract: A hollow golf club head according to this invention includes a face portion, a crown portion, and a sole portion, and is formed by connecting a plurality of shell members to each other. This golf club head includes a rib which is provided in the sole portion and used to adjust an impact sound. The plurality of shell members are divided using at least the rib as a boundary. The plurality of shell members include a rib forming shell member including a sole portion forming portion which forms part of the sole portion, and a rib forming portion which stands upright from the end of the sole portion forming portion and forms the rib.

Abstract: A putter head includes: a face; a first group of grooves which are mutually-parallel grooves; and a second group of grooves which differ in depth from the first group of grooves, wherein the face includes the first group of grooves and the second group of grooves.

Abstract: A putter head includes a head main body having a recess portion in a face surface of the putter head, and a face insert disposed in the recess portion. The face insert has a slit extending upward from a bottom face thereof In the bottom face, the slit may extend from the vicinity of a toe-side end thereof to the vicinity of a heel-side end thereof A bottom end of the slit may be located on a rear edge of the face insert. A ceiling face of the slit may be in a shape of an arch from the toe side to the heel side. The slit may be filled with a viscoelastic material.

Abstract: A simulation method for evaluating the aerodynamic performance of a golf club head uses arithmetic operations executed by a computer to analyze air flow around the head of a golf club when the club is swung, and thereby estimates the aerodynamic forces which act on the club head. Because the aerodynamic properties of a golf club head are evaluated without relying on experimental evaluations using physical prototypes, this method enables the efficient development of golf clubs.

Abstract: This invention provides a putter head comprising a head body and a face insert mounted on a face surface of the head body. Slits are vertically aligned in multiple stages so as to extend in the face insert in a toe-to-heel direction. A depending portion is provided in the slit on a side of the face surface so as to reduce a vertical dimension of the slit. The slit is filled with a viscoelastic material.

Abstract: A golf club head of this invention includes a head body, a weight member attached to the head body, and a fixing unit to fix the weight member at one of a plurality of attachment positions of the head body. The plurality of attachment positions are located on a virtual cylindrical surface having the axis of a shaft to be mounted to the golf club head as a center.

Abstract: This invention provides a hollow golf club head including a face portion, a crown portion, and a sole/side portion including a sole portion and a side portion. This golf club head includes a rib which extends from the toe side to the heel side in the sole portion, and a weight portion which is provided in the sole portion on the side of the face portion with respect to the rib or the back side with respect to the rib, and increases the amplitude of vibration of the sole portion.

Abstract: A golf club head of this invention includes a head body, a weight member attached to the head body, and a fixing unit to fix the weight member at any one of a plurality of attachment positions of the head body. The plurality of attachment positions are located on a straight line included in a plane. The plane includes the center-of-gravity position of the head body without the weight member attached thereto and is perpendicular to the toe-and-heel direction of the head body.

Abstract: A golf club head having a hollow construction produces a characteristic low ball hitting sound to accommodate the diversity of golfers' preferences for ball hitting sounds even if the volume of the golf club head is increased to 430 to 500 cc and the weight thereof is decreased to 160 to 220 g. In a golf club head having a hollow construction and including a face part, a sole part, a crown part, and a side part, in which the head volume is 430 to 500 cc, and the head weight is 160 to 220 g, the area of the sole part is increased so that the primary natural frequency of the sole part is 2400 Hz or less, and a weight is formed at a position of the center of vibration in the sole part on the inner surface on the hollow construction side of the sole part.

Abstract: A golf club head according to this invention is a hollow golf club head including a face portion, a crown portion, and a sole portion. The sole portion includes a first region which starts from the boundary portion between the sole portion and the face portion, and a second region which is spaced apart from the boundary portion toward the back side, and is adjacent to the first region. The second region is thinner than the first region and a third region adjacent to the back-side periphery of the second region. The second region includes the position of an antinode of the primary vibration mode of the sole portion at the time of impact.

Abstract: This invention provides a putter head comprising a head body and a face insert mounted on a face surface of the head body. A notched portion is provided in a rear surface of the face insert to extend upward from a lower end portion.

Abstract: This invention provides a method of identifying an antinode of a primary vibration mode of the golf club head having a hollow golf club head having a face portion, a crown portion, a sole portion, and a side portion. A viscoelastic body is to be mounted in at least one of the face portion, crown portion, sole portion, and side portion. The viscoelastic body is mounted in a part of a portion where the viscoelastic body is to be mounted, the part corresponding to an antinode of a primary vibration mode.

Abstract: This invention provides a golf club head comprising a plurality of scorelines formed in its face. The golf club head is configured such that an angle ? of the side wall of the scoreline with respect to the face is 70° or less, the edge of the scoreline has a ridged portion projecting from the face, and a height H of the ridged portion from the face satisfies: 5 ?m?H?20 ?m.

Abstract: A golf head club has a high moment of inertia and thus produces a pleasing hitting sound. A metallic golf club head 1 having a hollow space therein includes a face member 30 provided with a face part 31, and a body member 10 provided with a sole part 11, a crown part 12, a side part 13, and ribs 20. The hollow space is defined by the inner surfaces of the face part 31, the sole part 11, the crown part 12, and the side part 13, and the wall surfaces of the ribs. The ribs 20 extend from the inner surface of the sole part 11 to the inner surface of the crown part 12, and the body member 10 is molded integrally by casting.

Abstract: A putter head has a head main body and a face insert mounted on a face surface of the head main body. The face insert has a slit which is cut in from an end face on a sole or top side of the face insert toward an opposite side thereof. In one embodiment, the slit is cut in from an end face on the sole side of the face insert toward the top side thereof. The slit may be extended obliquely such that the top side of the slit is located forward of the face insert. In another embodiment, the slit is cut in from the side face on the top side of the face insert toward the sole side thereof. The slit may be extended obliquely such that the sole side of the slit is located rearward of the putter head. Any slit may be extended from the side face on a toe side of the face insert to the side face on a heel side thereof. The face inserts may contain viscoelastic material loaded in the slit.

Abstract: A putter head includes a head main body having a depressed portion and a face insert disposed within the depressed portion so that the face insert is mounted in a face surface of the head main body. The face insert includes at least one low hardness portion and at least one high hardness portion. The face insert has a boundary face between the at least one low hardness portion and the at least one high hardness portion which is inclined relative to a back-to-forth direction of the putter head. The boundary face may decline toward the rear or may rise toward the rear. The face insert may comprise a plurality of the low hardness portions and a plurality of the high hardness portions so that the low and high hardness portions are arranged vertically in multiple layers. The sectional shapes taken perpendicularly to the back-to-forth direction of the high hardness portion and the low hardness portion may be substantially of a right triangle.

Abstract: A hollow golf club head according to this invention includes a face portion, a crown portion, and a sole/side portion including a sole portion and a side portion. The sole/side portion includes a thin region formed to traverse at least the sole portion from the toe side to the heel side, and thick regions formed on the side of the face portion and the back side, respectively, with respect to the thin region to be adjacent to the thin region. The golf club head further includes a rib which extends from the toe side to the heel side only in the thin region of the thin region and the thick region, and is connected to the side portion on the toe side and the side portion on the heel side.

Abstract: This invention provides a golf club head including a plurality of parallel scorelines formed in its face surface, and a plurality of grooves which are formed in the face surface and have a width narrower than the scorelines. Rounded portions are formed on the edges of the scorelines. The plurality of grooves are formed at positions on the two sides of each of the scorelines to extend parallel to the scorelines.

Abstract: This invention provides a golf club head processing method of performing blast processing on a face surface on which a scoreline is formed. The processing method according to this invention includes the steps of filling the scoreline with a masking material before the blast processing, and removing the masking material from the scoreline after the blast processing.