Abstract: A golf club head according to the present invention includes a golf club head body that has a crown portion, a sole portion, and a side portion, and has an opening surrounded by the crown portion, the sole portion, and the side portion; and a face portion that blocks the opening of the golf club head body. The face portion is shaped as cup that has a base portion shaped as a flat plate and a peripheral portion that extends from a periphery of the base portion. With respect to the face-back direction, the width of the peripheral portion on the toe side in a plan view is longer than the width of the peripheral portion on the heel side in a plan view.

Abstract: A golf club head according to the present invention includes a golf club head body that has a crown portion, a sole portion, and a side portion, and has an opening surrounded by the crown portion, the sole portion, and the side portion; and a face portion that blocks the opening of the golf club head body. The face portion is shaped as cup that has a base portion shaped as a flat plate and a peripheral portion that extends from a periphery of the base portion. With respect to the face-back direction, the width of the peripheral portion on the toe side in a plan view is longer than the width of the peripheral portion on the heel side in a plan view.

Abstract: A golf club head provided with a hollow includes a head main portion made of metal material with an opening, a cover member made of fiber reinforced resin and covering the opening, wherein the opening includes a crown opening region provided in a crown portion and a sole-side opening region provided in the sole and side portions, and the crown opening region has an opening area projected onto an outer surface of the club head in a range of from 63 to 77% of a superficial area of the crown portion. The sole-side opening region has an opening area projected onto the outer surface of the club head being in a range of from 4 to 25% of the superficial area of the sole portion and the side portion in sum total.

Abstract: A hollow golf club head comprises a main body member provided with a face opening and a sole opening, a face member brazed/soldered to the main body member to close the face opening, and a sole member brazes/soldered/welded to the main body member to close the sole opening. The main body member has a thin front edge part of the sole opening and a thick heat blocking part between the thin front edge part and the face portion. The sole member has a front edge part connected to the sole opening's front edge part and a thicker sole reinforcing part positioned backward thereof. The thicknesses of the sole member's front edge part and the sole opening's front edge part are not less than 0.5 mm and less than 2.5 mm. The thicknesses of the sole reinforcing part and the heat blocking part are 2.5 to 10.0 mm.

Abstract: A hollow golf club head comprises a main body member provided with a face opening and a sole opening, a face member brazed/soldered to the main body member to close the face opening, and a sole member brazes/soldered/welded to the main body member to close the sole opening. The main body member has a thin front edge part of the sole opening and a thick heat blocking part between the thin front edge part and the face portion. The sole member has a front edge part connected to the sole opening's front edge part and a thicker sole reinforcing part positioned backward thereof. The thicknesses of the sole member's front edge part and the sole opening's front edge part are not less than 0.5 mm and less than 2.5 mm. The thicknesses of the sole reinforcing part and the heat blocking part are 2.5 to 10.0 mm.

Abstract: A golf club head provided with a hollow includes a head main portion made of metal material with an opening, a cover member made of fiber reinforced resin and covering the opening, wherein the opening includes a crown opening region provided in a crown portion and a sole-side opening region provided in the sole and side portions, and the crown opening region has an opening area projected onto an outer surface of the club head in a range of from 63 to 77% of a superficial area of the crown portion. The sole-side opening region has an opening area projected onto the outer surface of the club head being in a range of from 4 to 25% of the superficial area of the sole portion and the side portion in sum total.

Abstract: A hollow golf club head comprises: a hollow main body made of a fiber-reinforced plastic; and a face member made of a metal material and forming at least a part of the club face, wherein the hollow main body is single-piece and comprises a front portion of which outer surface is covered with the face member bonded thereto.

Abstract: A face backside of a golf club head is provided with six or more ribs extended from a face center toward face circumferences. Angles ?1 to ?6 between respective pairs of adjoining ones of the ribs are less than 90°. One of the ribs that form the smallest angle between its extension direction and a head vertical direction d1 and that extends from the face center toward a crown-side face circumference constitutes an upward rib, which has a smaller cross-sectional area than any of those of the other ribs.

Abstract: A golf club head includes a face including a bulge formed at the center of a backside thereof and having a thickness of 2.0 or more times the thickness of the thinnest part, and a plurality of ribs extended from the bulge toward a circumference of the face. Six or more ribs are provided as the plural ribs and an angle ?(°) formed between extension directions of a respective pair of adjoining ribs is less than 90°. The maximum thickness of the bulge is not more than 3.5 times the thickness of the thinnest part.

Abstract: The present invention is a golf putter head wherein the second moment among the three inertial moments described below shows a maximum value in a state in which the head is placed on a horizontal plane at a specified lie angle and loft angle: First moment: inertial moment about a first axis which passes through the center of gravity of the head, and which is parallel to the face surface and said horizontal plane; Second moment: inertial moment about a second axis which is an axis in the vertical direction that passes through the center of gravity of the head; and Third moment: inertial moment about a third axis which passes through the center of gravity of the head, and which is perpendicular to said first axis and perpendicular to said second axis.

Abstract: The present invention is a golf putter head wherein the second moment among the three inertial moments described below shows a minimum value in a state in which the head is placed on a horizontal plane at a specified lie angle and loft angle: First moment: inertial moment of the head about a first axis which passes through the center of gravity of the head, and which is parallel to the face surface and said horizontal plane; Second moment: inertial moment of the head about a second axis which is an axis in the vertical direction that passes through the center of gravity of the head; and Third moment: inertial moment of the head about a third axis which passes through the center of gravity of the head, and which is perpendicular to said first axis and perpendicular to said second axis.

Abstract: A hollow golf club head comprises: a hollow main body made of a fiber-reinforced plastic; and a face member made of a metal material and forming at least a part of the club face, wherein the hollow main body is single-piece and comprises a front portion of which outer surface is covered with the face member bonded thereto.

Abstract: A method for designing a golf club head by using a computer. A golf club head model in which the rear surface of a face part is provided with reinforcing ribs and a golf ball model to be analyzed by using a finite element method (FEM) are prepared. Conditions including the positions of the reinforcing ribs and the configurations thereof including the sectional areas and heights are adjusted to set the maximum value of the Mises stresses generated by the collision between the golf ball model and the golf club head model at any off-center positions of said front surface of said face part thereof to less than 1.3 times the maximum value of the Mises stress generated by the collision between the golf ball model and the golf club head model at the center of said front surface of said face part thereof.

Abstract: A golf club head includes a face including a bulge formed at the center of a backside thereof and having a thickness of 2.0 or more times the thickness of the thinnest part, and a plurality of ribs extended from the bulge toward a circumference of the face. Six or more ribs are provided as the plural ribs and an angle ?(°) formed between extension directions of a respective pair of adjoining ribs is less than 90°. The maximum thickness of the bulge is not more than 3.5 times the thickness of the thinnest part.

Abstract: A wood-type golf club including a club shaft and a club head, wherein the club length is in a range of from 43 to 48 inches, the volume of the club head is in a range of not less than 250 cc, and the torque T in degree of the club shaft and the gravity point distance L in mm between the gravity point of the club head and the center line of the club shaft satisfy conditions (1) T?0.143L?2.79 and (2) T?0.286L?7.14.

Abstract: A golf club comprises a club shaft and a hollow club head, wherein the club head has a loft angle of from 14 to 18 degrees, a head volume of not less than 250 cc, and a sweet spot at a vertical distance of from 1 to 5 mm downwards of a face center, and the club shaft has a variable flexural rigidity whose minimum is in a range of from 5 to 10 N·m2, and the minimum flexural rigidity occurs in a range between 0% and 40% of the length of the club shaft from the end of the club shaft.

Abstract: A face backside of a golf club head is provided with six or more ribs extended from a face center toward face circumferences. Angles ?1 to ?6 between respective pairs of adjoining ones of the ribs are less than 90°. One of the ribs that form the smallest angle between its extension direction and a head vertical direction d1 and that extends from the face center toward a crown-side face circumference constitutes an upward rib, which has a smaller cross-sectional area than any of those of the other ribs.

Abstract: An iron-type golf club head comprises a face portion whose surface defines a club face for hitting a ball, the face portion is provided with a thin part which is defined as having a thickness of not more than 3 mm, the thin part defines at least a part of the club face including a sweet spot, and the distance across the thin part measured in every direction is not less than 30 mm.

Abstract: A wood-type golf club head which has a head volume of not less than 320 cc, a gravity point distance (C) in a range of from 25 to 35 mm, and a heel area width (A) in a range of from 30 to 52% of a clubhead width (B).

Abstract: The present invention is a golf putter head wherein the second moment among the three inertial moments described below shows a maximum value in a state in which the head is placed on a horizontal plane at a specified lie angle and loft angle: First moment: inertial moment about a first axis which passes through the center of gravity of the head, and which is parallel to the face surface and said horizontal plane; Second moment: inertial moment about a second axis which is an axis in the vertical direction that passes through the center of gravity of the head; and Third moment: inertial moment about a third axis which passes through the center of gravity of the head, and which is perpendicular to said first axis and perpendicular to said second axis.