Abstract: This invention provides a golf club head having a first viscoelastic body made of a first viscoelastic material and a second viscoelastic body made of a second viscoelastic material with a loss coefficient the temperature dependence of which is different from that of a loss coefficient of the first viscoelastic material.

Abstract: This invention provides a golf club head comprising a head main body, a face plate fixed to a front surface side of the head main body to form a face surface, a cavity portion formed in the head main body and open to a face plate side, and a viscoelastic body inserted in a compressed state in a space formed by the cavity portion and the face plate. An end face on the face plate side of a circumferential wall defining the cavity portion comprises a contacting portion contacting with a rear surface of the face plate, and a non-contacting portion spaced apart from the rear surface of the face plate to form a gap communicating with the cavity portion between the non-contacting portion and the rear surface of the face plate.

Abstract: This invention provides a golf club head including a face member. The face member includes a face portion forming a face, and a crown extending portion extending backward from the upper edge of the face portion. The width of the crown extending portion in a face to back direction at the toe side is larger than that in the face to back direction at the heel side.

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 having a viscoelastic body, wherein the viscoelastic body is made by mixing a plurality of types of viscoelastic materials with loss coefficients temperature dependences of which are different.

Abstract: This invention provides a hollow golf club head in which the ratio of the rigidity of a sole portion to that of a crown portion is 1:0.1 to 0.8. This invention also provides a hollow golf club head in which a crown low-rigidity region is formed on the face side of the crown portion, and a crown high-rigidity region is formed on the back side of the crown portion. The ratio of the rigidity of the crown high-rigidity region to that of the crown low-rigidity region is 1:0.2 to 0.6. Furthermore, this invention provides a hollow golf club head in which a sole high-rigidity region is formed on the face side of the sole portion, and a sole low-rigidity region is formed on the back side of the sole portion. The ratio of the rigidity of the sole high-rigidity region to that of the sole low-rigidity region is 1:0.2 to 0.5.

Abstract: A wood club head having a loft angle of not less than 13° is provided. The hosel length is not less than 20 mm. The face progression is set to fall within a range of 12 mm to 16 mm (both exclusive). The barycenter depth is set to fall within a range of 20 mm to 25 mm (both exclusive).

Abstract: The present invention provides a golf club head capable of lessening the decrease in carry even for an off-center hit. In a golf club head in which a face part 2 of a metallic head body 1 having a hollow part therein is formed with an opening 8 communicating with the hollow part, and a metallic face plate 9 is welded to the opening 8, notch parts 8A and 8B connecting with the opening 8 are formed in a part on the toe 6 side of a crown part 3 and a part on the heel 7 side of a sole part 4, respectively; and the upper end portion of the face plate 9 is extended so as to compensate the notch part 8A in the crown part 3 and welded to the notch part 8A, and the lower end portion thereof is extended so as to compensate the notch part 8B in the sole part 4 and welded to the notch part 8B.

Abstract: A hollow golf club head is provided that includes a face portion, a sole portion extending backward from a lower portion of the face portion to form a bottom portion of the golf club head, a crown portion extending backward from an upper portion of the face portion to form an upper portion of the golf club head, and a vibration absorbing layer in a film form composed of an elastic body on an inner surface of the crown portion. The sole portion and the crown portion are configured such that a ratio of a rigidity of the sole portion to a rigidity of the crown portion is 1: 0.1 to 0.8, and the vibration absorbing layer has a ring shape covering an outer peripheral portion of the crown portion. The launch angle of a ball is increased so that the traveling distance of a shot can be increased.

Abstract: The accuracy or computation speed of mechanical analysis of a golf ball using the finite element method is increased. In the mechanical analysis, a model representing the golf ball is prepared on a computer, and computation is made by the finite element method using elements and nodes. At this time, the elements are made solid elements of hexahedron, the aspect ratio of the shape of each element is set so as to be not lower than 1.0 and not substantially higher than 6.5, and nodes are provided on the sides and at the vertexes of the hexahedron of element.

Abstract: This invention provides a hollow golf club head in which the ratio of the average thickness of a sole portion to that of a crown portion is 1:0.3 to 0.8. Preferably, a crown thin-walled region is formed on the face side of the crown portion, and a crown thick-walled region is formed on the back side of the crown portion. The ratio of the average thickness of the crown thick-walled region to that of the crown thin-walled region is 1:0.5 to 0.9.

Abstract: This invention provides a hollow golf club head including a fixing member which includes a shaft body formed with a threaded portion at one end, and a head portion at the other end of the shaft body, a viscoelastic body having an opening through which the shaft body extends, a recess portion formed in a circumferential wall of the golf club head and in which the viscoelastic body is disposed, and a screw hole formed in a bottom portion of the recess portion and threadably engages with the threaded portion. The viscoelastic body is fixed between the head portion and the bottom portion by threadably engaging the threaded portion with the screw hole.

Abstract: A golf club head includes a face member having a ball-striking face and an oval thick portion positioned in a central portion of the ball-striking face. The oval thick portion has an oval shape having recesses formed by recessing both sides in a major axis direction in an arc-shaped fashion. The recesses are directed to a toe-side upper portion and a heel-side lower portion. The thickness of the thick portion becomes thickest at a central portion and is gradually reduced from the central portion towards the periphery. The face member is formed such that a portion outside the thick portion is thinner than the thick portion. An occupancy rate of the oval thick portion in the ball-striking face is in a range of 25 to 45%.

Abstract: This invention provides a hollow golf club head having a crown portion and a sole portion. Young's modulus of a material among materials of the crown portion which is used in the largest amount is lower than Young's modulus of a material among materials of the sole portion which is used in the largest amount.

Abstract: This invention provides a hollow golf club head having a face portion, a crown portion, a sole portion, and a side portion. The head has 0.3 to 0.6-mm thick thin-walled regions on the face side of the crown portion and the face side of the side portion, a medium-thick-walled region thicker than the thin-walled region of the crown portion at the back of the thin-walled region, and a high-rigidity region on the face side of the sole portion.

Abstract: This invention provides a golf club head including a head main body, a face plate and a hollow portion. The head main body includes an opening in a face portion, and the opening is provided with a plurality of pawls to receive the face plate which is to fit in the opening. The pawls include a large pawl and a small pawl. The large pawl is arranged in each of a heel-side upper portion and a toe-side lower portion and the small pawl is arranged in at least either one of a heel-side lower portion and a toe-side upper portion when the opening is divided into four vertically and horizontally about a face center as the center. The face plate is fitted in the opening and fixed by welding.

Abstract: There is provided a golf club head capable of increasing carry on average even if being used by an amateur golfer who is prone to hit a ball with various hit points across the clubface. A golf club head 1 has a face part 2, a crown part 3, a sole part 4, a side part 5, and a hosel part 6, which are formed of titanium or a titanium alloy. The golf club head 1 is formed by integrating a head body 10 and a face plate 30 with each other by welding such as laser welding or plasma welding. A thick part 20 is provided only in the central portion in the toe-heel direction of the cross corner portion between the face part 2 and the sole part 4. The width in the toe-heel direction of the thick part 20 is 20 mm or narrower.

Abstract: A hollow golf club head includes a face part, a crown part, a sole part, a side part, and a hosel part. The head has a volume of 300 to 460 cm3 and a weight of 175 to 220 g. The crown part includes a large-thickness crown part formed along an overall edge thereof, and a small-thickness crown part which is formed inside the large-thickness crown part and has a thickness less than a thickness of the large-thickness crown part. The side part includes a heel-side small-thickness side part formed at a heel side, a toe-side small-thickness side part formed at a toe side, and a large-thickness side part which is formed at a portion of the side part other than the heel-side small-thickness side part and the toe-side small-thickness side part and has a thickness greater than thickness of the side parts.

Abstract: A hollow golf club head includes a face part, a crown part, a sole part, a side part, and a hosel part. The head has a volume of 80 to 200 cm3 and a weight of 205 to 250 g, a distance between face-side and back-side edges divided by a distance between a toe-side edge and a intersecting point on a heel-side edge of a horizontal line passing through a face center point is 0.3 to 0.7. The crown part includes a large-thickness crown part formed along an overall edge thereof, and a small-thickness crown part formed inside the large-thickness crown part. The side part includes a heel-side small-thickness side part formed at a heel side, a toe-side small-thickness side part formed at a toe side, and a large-thickness side part formed at a portion of the side part other than the heel-side and toe-side small-thickness side parts.

Abstract: This invention provides a wood golf club head having a loft angle of not more than 15°. In this golf club head, a progression length FP from a leading edge of a face to an axis line of a shaft axis and a horizontal length VZG from the leading edge of the face to a center of gravity of the head in a depth direction satisfy the following expression; ?2<VZG?2×FP<2.