Sri Sports Limited

Dunlop Sports Company Limited

Sumitomo Rubber Industries Limited

Hirotaka Nakamura

Keiji Ohama

Takahiro Sajima

Kazuhiko Isogawa

Naruhiro Mizutani

Kazuya Kamino

Daisuke Kohno

Hyoungchol Kim

Yuki Motokawa

Satoko Okabe

Kiyofumi Matsunaga

Toshiyuki Tarao

Takahiro Shigemitsu

Seiichiro Endo

Tsutomu Hirau

Jun Kodaka

Kazuhiko Isoagawa

Kazuyoshi Shiga

Keiji Moriyama

Masahide Onuki

Hiroshi Hasegawa

Yoshiko Matsuyama

Yumi Kanemitsu

Tatsuya Yashiki

Shinya Furuta

A golf club head includes: a head body that includes a cavity; a weight that is detachably attached to the cavity; and a cover that is openably and closably attached to the head body and that covers at least a part of the cavity when the cover is in a closed state. The weight is attached to the cavity in a state where the weight is slidingly movable in the cavity. In the closed state, the cover applies a pressing force to the weight. The weight may be fixed to the cavity by a static frictional force increased by the pressing force. The cavity may form a slide groove.

Golf club head with sliding weight and cover

A head includes a face portion, a crown portion, a sole portion, and a hosel portion. The crown portion includes a protruding portion on a crown outer surface. The protruding portion does not form any part of an outer contour line of the head in a front view of the head as viewed from a face side. The protruding portion forms an outer contour line of the head in a heel projection figure in which the head that is placed on a ground plane such that a shaft axis line is perpendicular to the ground plane and a face angle is 0° is viewed from a heel side along the ground plane. In this head, aerodynamic drag and lifting force at a position at which the shaft axis line becomes parallel to the ground plane during downswing can be increased. In this head, air resistance at impact can be suppressed.

Golf club head and golf club

A state of a head placed such that its shaft axis is vertical to a horizontal plane and a face normal line is parallel to a perpendicular plane on which the shaft axis lies is defined as a 0-degree state. A direction parallel to the perpendicular plane and parallel to the horizontal plane is defined as a projection direction. A projected area of the head projected in the projection direction when the head is rotated by θ° about the shaft axis toward a back side from the 0-degree state is denoted by WAθ. WAθ is divided by the shaft axis into an area Afθ and an area Abθ. Airflow causes a force acting on the area Afθ in a face-closing direction and a force acting on the area Abθ in a face-opening direction. (Af−Ab) is −4500 (mm) or less. (Af−Ab) is 4700 (mm) or less.

Golf club head

A golf club head includes a metallic head body having an opening, and an FRP member fixed to the head body so as to close the opening. The FRP member is a fiber-reinforced plastic including fibers and thermoplastic resin. The head body includes a support portion around the opening. The support portion has a first surface for supporting the FRP member. The first surface is provided with at least one narrow groove having a groove width of 20 to 80 μm and a groove depth of 100 to 400 μm, and a part of the thermoplastic resin of the FRP member is solidified inside the at least one narrow groove.

A golf club shaft includes a tip end, a butt end, a first anisotropic portion that is twisted in a first direction in conjunction with a bending of the golf club shaft at a circumferential bending position, and a second anisotropic portion that is twisted in a second direction in conjunction with the bending. The second anisotropic portion is located on a tip end side relative to the first anisotropic portion. The second direction is opposite to the first direction. In the shaft, the twist accompanied by the bending in the first anisotropic portion can be offset by the twist accompanied by the bending in the second anisotropic portion.

Golf club shaft

An EI value at a point Pseparated by 16 inches from a tip end Tp is defined as E, a shaft wall thickness at the point Pis defined as T, an EI value at a point Pseparated by 6 inches from the tip end Tp is defined as E, and a shaft wall thickness at the point Pis defined as T. In a shaft, Eis 2.4 (kgf&#xb7;m) or more, Eis 2.7 (kgf&#xb7;m) or less, and E/Eis 0.95 or more but 1.50 or less, E/Tis 1.9 or less, and E/Tis 3.0 or more. A high-elasticity partial reinforcement layer including a fiber having a tensile elastic modulus of 30 (t/mm) or more but 40 (t/mm) or less is disposed in at least a part of a region falling within a range of &#xb1;4 inches from the point P

A shaftincludes a plurality of layers formed by fiber reinforced resins. The layers include a hoop layer and bias layers. The hoop layer includes a full length hoop layer sconstituted with a prepreg having a fiber elastic modulus of equal to or greater than 30 (tf/mm) and having a fiber weight per unit area of equal to or greater than 50 (g/m) but equal to or less than 80 (g/m). The bias layers s, s, s, and sinclude high elasticity containing bias layers sand sconstituted with a prepreg contacting a high elastic pitch-based carbon fiber having a fiber elastic modulus of equal to or greater than 80 (tf/mm). Preferably, the full length hoop layer sis disposed outside the high elasticity containing bias layers sand s

A golf clubincludes a head, a shaftand a grip. The shaftincludes a plurality of layers, a tip end Tp and a butt end Bt. If a distance between a center of gravity of the shaft and the butt end Bt is defined as Lg (mm), a shaft full length is defined as Ls (mm), and a ratio of the distance Lg to the shaft full length Ls is defined as a ratio of the center of gravity of the shaft, the ratio of the center of gravity of the shaft is 44.5% or less. If a torsional rigidity at a point of 90 mm distant from the tip end Tp is defined as GJt (kgf&#xb7;m), and a torsional rigidity at a point of 210 mm distant from the butt end Bt is defined as GJb (kgf&#xb7;m), GJb/GJt is 5.5 or less.

Golf club

A golf ballincludes a spherical core, a mid layer, and a cover. The coreis obtained by crosslinking a rubber composition. The difference between: a hardness H(5.0) at a point which is located at a distance of 5 mm from the central point of the core; and a hardness Ho at the central point is 6.0 or greater. The difference between: a hardness H(12.5) at a point which is located at a distance of 12.5 mm from the central point; and the hardness H(5.0) is 4.0 or less. The difference between a hardness Hs at the surface of the coreand the hardness H(12.5) is 10.0 or greater. The difference between the hardness Hs and the hardness Ho is 22.0 or greater. There is no zone in which a hardness decreases from the central point to the surface. A Shore D hardness H3 of the cover is greater than a Shore D hardness H2 of the mid layer.

Golf ball

A shaftincludes at least two hoop layers sand s, at least one bias layer, and at least one straight layer. An interposition layer other than the hoop layer is present between every opposing hoop layers. An average thickness of the opposing hoop layers is defined as t, and a total thickness of the interposition layer is defined as T. The shaftsatisfies the following formula (1):&#x2267;1.9&#x2003;&#x2003;(1).

A golf ballhas, on a surface thereof, a plurality of types of dimpleshaving different diameters from each other. A standard deviation V&#x3c3; of the volumes of all the dimplesis equal to or less than 0.095 mm. The ratio (V&#x3c3;/D&#x3c3;) of the standard deviation V&#x3c3; to a standard deviation D&#x3c3; of the diameters of all the dimplesis equal to or less than 0.35. Preferably, the shape of each dimpleis a portion of a spherical surface. The standard deviation V&#x3c3; is preferably equal to or less than 0.087 mm. The ratio (V&#x3c3;/D&#x3c3;) is preferably equal to or less than 0.29.

A shaftis formed by a plurality of prepreg sheets s, s, s, s, s, s, s, sand s. These prepreg sheets include full length sheets and partial sheets partially provided in the axial direction of the shaft. The full length sheets include a full length hoop sheet s. The partial sheets include glass fiber reinforced sheets s, s. In the shaft, a volume ratio Vf of the hoop layer in a specific tip part Tx is equal to or greater than 2.5% and less than 10%. The shaftis lightweight and has a high degree of design freedom of a position of a center of gravity. The shaftis excellent in strength of a tip part.

A wood golf club head, which is provided therein with a hollow section and for which a crown section that forms the upper surface of the head is formed from a metal material. The crown section includes a heel portion; a toe portion with a smaller thickness than the heel portion; and a thickness transition section provided between the heel portion and the toe portion, the thickness of which decreases gradually from the heel portion to the toe portion. In the top view of a reference state in which the head is placed on a horizontal plane with a specified lie angle and loft angle, the thickness transition section extends as a smooth curve that protrudes towards the toe side.

Wood-type golf club head

A shaftincludes a plurality of fiber reinforced resin layers sto s. The plurality of layers include a first straight layer sin which a 0&#xb0;-compression strength is the minimum and a second straight layer sin which a 0&#xb0;-compression strength is the maximum. A specific tip part Tx which is a region between a tip end Tp and a position separated by 100 mm from the tip end Tp satisfies the following (a) to (c):

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Kobe, Japan

Hirotaka Nakamura