Abstract: A golf club head includes a main body having a top portion, a bottom portion, a striking face, and an interior surface. A weight member is coupled to the interior surface of the main body. In an imaginary vertical plane that passes through the weight member, the interior surface of the main body comprises a first point and a second point. An imaginary line passes through the first point and the second point. A first imaginary boundary line and a second imaginary boundary line, both passing through the weight member and being perpendicular to the imaginary line, pass through the first point and the second point, respectively. Between the first point and the second point, the interior surface of the main body has an irregularity factor of at least 1.2 and the weight member comprises a distribution factor of at most 1.0 and a conformity factor of at most 0.07.

Abstract: A prediction method according to the present invention is a method for predicting a modal damping ratio of a composite head including two or more kinds of materials including a first material and a second material. The method includes the steps of: presuming at least a coefficient Px of a generalized Maxwell model M1 in the first material using a known material damping ratio ?1; obtaining a calculation model of the head using the generalized Maxwell model M1; and calculating the modal damping ratio of the head based on analysis of the head using the calculation model. Preferably, the Maxwell model is further used also for the second material. Preferably, the method further includes the step of presuming a coefficient Py of a generalized Maxwell model M2 in the second material using a known material damping ratio ?2.

Abstract: The object of the present invention is to provide a golf ball having superior abrasion resistance, durability and spin performance. The present invention provides a golf ball of the present invention has a core and a cover, wherein the cover is formed from a cover composition that contains, as a resin component, a thermoplastic polyurethane (A) and a urethane prepolymer (B) having two or more isocyanate groups.

Abstract: A golf club head 2 comprises: a porous part Ps including a porous metal and integrally formed; and a non-porous part NPs. The porous part Ps constitutes at least a part of a sole 8. The porous part Ps has a whole thickness part Pt occupying a whole thickness of the sole 8. Preferably, a rate Ra of an area occupied by the whole thickness part Pt among an area of the sole is equal to or greater than 15%. Preferably, the porous part Ps and the non-porous part NPs are welded mutually. In the disposal of the porous part Ps in the head 2, preferably, a substituted head obtained by substituting the porous part Ps with the same material as that of the non-porous part NPs adjacent to the porous part Ps is considered.

Abstract: Golf ball 2 has spherical core 4, surrounding layer 6 situated on the external side of the core 4, mid layer 8 situated on the external side of the surrounding layer 6, cover 10 situated on the external side of the mid layer 8, and paint layer 12 situated on the external side of the cover 10. The mid layer 8 has a thickness Tm of 0.1 mm or greater and 1.2 mm or less. The ratio (Tc/Tm) of the thickness Tc of the cover 10 to the thickness Tm of the mid layer 8 is no greater than 0.50. The cover 10 has a Shore D hardness Hc of no greater than 35. The Shore D hardness Hm of the mid layer 8 is greater than the Shore D hardness Hc of the cover 10. The base material of the surrounding layer 6 is an ionomer resin. The base material of the mid layer 8 is a polyurethane. The base material of the cover 10 is a polyurethane.

Abstract: A cross-sectional shape of each of dimples 8 of a golf ball is a wave-like curve. The wave-like curve has two first projections 16, two second projections 18, two first recesses 20, and two second recesses 22. A circular arc 14 passes through one edge Ed, a deepest point Pd, and another edge Ed. Each first projection 16 is located above the circular arc 14. Each second projection 18 is located above the circular arc 14. Each first recess 20 is located below the circular arc 14. Each second recess 22 is located below the circular arc 14. The ratio of the distance Lp from an edge Ed to a peak Pp to the radius (Di/2) of the dimple 8 is equal to or greater than 20% but equal to or less than 70%.

Abstract: A golf club head 2 includes a face 4, a crown 6, a sole 8, and a side 10. At least a part of the crown 6, at least a part of the sole 8, or at least a part of the side 10 is formed by a porous part Ps including a porous metal. Porosity on a surface side of the porous part Ps is smaller than porosity on an inner side of the porous part Ps. Preferably, the porous part Ps has skin layers Ls formed on both sides thereof and a core layer Lc formed therebetween. Porosity of the skin layer Ls is smaller than that of the core layer. Preferably, a thickness of the skin layer is 0.05 mm or greater and 0.2 mm or less. Preferably, the whole porous part Ps is integrally formed.

Abstract: A method of selecting a preferred golf shaft for a player who uses an existing golf shaft, according to one or more aspects of the present invention, may comprise gathering a plurality of empirical data sets, each data set corresponding to an individual golf shaft selected from a plurality of golf shafts; providing a plurality of specification codes, each associated with an individual empirical data set of the plurality of empirical data sets; from the plurality of specification codes, identifying a first specification code associated with the existing golf shaft; gathering feedback associated with the existing golf shaft from the player; and using the feedback to select, from the plurality of specification codes, a second specification code corresponding to the preferred golf shaft.

Abstract: A hollow golf club head having face end and tail ends, a strike face at the face end, a crown, a sole of length >3.5 inches, volume 0.300 cm3, and a structural response modifying constraining member having first and second ends, the second being forward of the first and spaced from the strike face, the constraining member extending vertically and in contact with the sole and the crown at its first and second ends, and extending horizontally a maximum distance that is <40% of the sole length, when the club head is in address position.

Abstract: A golf ball which has excellent abrasion-resistance and spin performance is provided. The golf ball of the present invention includes a core and a cover covering the core and containing polyurethane as a resin component, wherein the polyurethane has, as a constituting component, a polyisocyanate component, a high-molecular weight polyol component, and a mixture of cis-1,4-cyclohexane dimethanol and trans-1,4-cyclohexane dimethanol as a chain extender.

Abstract: A golf club head includes a primary component and a secondary component, wherein the secondary component is rotatably or pivotally associated with the rear surface of the primary component. The secondary component is adjustable between a first orientation and a second orientation relative to the primary component such that the golf club head has a first sole contour when the secondary component is in the first orientation and a second sole contour when the secondary component is in the second orientation, the first sole contour being different from the second sole contour.

Abstract: The present invention relates to a method of manufacturing an FRP tubular body. The manufacturing method includes the steps of winding a fiber reinforced resin member containing a fiber and a matrix resin around a mandrel, thereby obtaining an intermediate formed body, winding a wrapping tape around an outer peripheral surface of the intermediate formed body (6) with an application of a tension, curing the matrix resin in the intermediate formed body having the wrapping tape wound therearound, and pulling the mandrel out and removing the wrapping tape after the curing step, thereby obtaining a cured tubular body. It is preferable that a fabric tape should be used as the wrapping tape. It is preferable that a tensile stress to be applied to the fabric tape (8) should be set to be equal to or higher than 5 (Mpa) and is equal to or smaller than 150 (Mpa) at the tape winding step. In the manufacturing method, the matrix resin can be effectively extracted at a subsequent step to the winding step.

Abstract: A designing method according to the present invention includes the steps of: (1) dividing a surface of a phantom sphere of a golf ball 2 into a plurality of units U by division lines 14 obtained by projecting edge lines of a regular polyhedron inscribed in the phantom sphere, on the surface of the phantom sphere; (2) obtaining a base pattern by randomly arranging a plurality of dimples 8 in one unit U such that the dimples 8 do not overlap each other; and (3) developing the base pattern over other units U such that patterns of two adjacent units U are not mirror-symmetrical to each other. The regular polyhedron is preferably a regular dodecahedron or a regular icosahedrons.

Abstract: A golf club has a reverse flex is 80 to 110 mm. The face portion includes a central thick part, a toe-crown-side thin part on a crown-side and on a toe-side of the central thick part, and a heel-sole-side thin part on a sole-side and on a heel-side the central thick part. In the front view of the head, a first straight line passing an area centroid of the toe-crown-side thin part and an area centroid of a back surface of the face portion has an angle ?A of 38 to 45 degrees, and a second straight line passing an area centroid of the heel-sole-side thin part and the area centroid of the back surface of the face portion has an angle ?B of 40 to 45 degrees, each with respect to the horizontal plane.

Abstract: A golf club 2 is provided with a head 4, a shaft 6, a grip 8, a head cavity body 10 mounted to the head, a grip cavity body 40 mounted to the grip 8, a head weight 12 attachable to/detachable from the head cavity body 10, and a grip weight 12 attachable to/detachable from the grip cavity body 40. A material of the grip cavity body is a polymer. A material of the head cavity body is a polymer. Preferably, the head weight 12 is attachable to/detachable from the grip cavity body 40. Preferably, the grip weight 12 is attachable to/detachable from the head cavity body 40. Preferably, in the golf club 2, a club mass can be adjusted without substantially changing a club balance.

Abstract: A golf club has a reverse flex of from 90 to 140 mm. In a front view of the golf club head under a standard state in which the golf club head is placed on a horizontal plane at its lie angle and loft angle, a first straight line drawn to pass through the centroid of the toe-crown-side thin portion and the centroid of the back surface of the face portion is inclined at an angle ?A of from 30 to 40 degrees with respect to the horizontal plane; and a second straight line drawn to pass through the centroid of the heel-sole-side thin portion and the centroid of the back surface of the face portion is inclined at an angle ?B of from 39 to 42 degrees with respect to the horizontal plane.

Abstract: A golf club comprises a club shaft and a golf club head attached to the tip end of the club shaft, wherein the length of the golf club is from 45 to 47 inches, the volume V of the golf club head is from 440 to 470 cu·cm, the moment of inertia M of the golf club head around the center line of the club shaft is 5500 to 6500 g sq·cm, and the ratio M/V of the moment of inertia M (g sq·cm) to the volume V (cu·cm) is from 11.0 to 13.5.

Abstract: A plurality of golf clubs having mutually different flex point rates of a shaft is prepared. A subject hits a golf ball with one reference club included in the golf clubs. A face angle of the golf club immediately before hitting is measured by an apparatus 10. A recommended flex point rate P is calculated by substituting, into the following mathematical expression, the face angle Q and the flex point rate R of the reference club: P=0.8648·Q+R?5.033 A golf club having a shaft whose difference between the flex point rate and the recommended flex point rate P is within a predetermined range is selected as a recommended club. The subject hits a golf ball with the recommended club. The apparatus 10 measures a speed, a launch angle, a backspin speed, a sidespin speed, and a deflection angle of the golf ball.

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 includes a sole, a crown, a skirt, and a striking face. The golf club includes a junction interconnecting the sole, crown, and skirt to the striking face, the junction including at least one stiffening member.