Sumitomo Rubber Industries Limited

Sri Sports Limited

Dunlop Sports Company Limited

Korea Advanced Institute of Science and Technology

Katsuji Matsunaga

Takeshi Asakura

Keiji Moriyama

Kazuyoshi Shiga

Masahiko Ueda

Naoyoshi Ueda

Mikio Yamada

Takahiro Sajima

Keiji Ohama

Satoshi Iwami

Takashi Sasaki

Yoshikazu Yabuki

Hiroaki Tanaka

Hidenori Hiraoka

Kaname Yamada

Kazunari Yoshida

Masatoshi Kato

Masaaki Kikuchi

Jae Soon Lee

Haruki Shinagawa

Sung Chul Kim

An evaluation method for hit feeling of a sport implement according to the present invention includes an acceleration measurement step for measuring acceleration of a sport hitting tooland a data analysis step for analyzing data obtained in the measurement. In the data analysis step, an amount of change in acceleration in a first cycle of vibration after hitting is calculated. The evaluation method evaluates hit feeling to be felt by a person, using the amount of change in the acceleration. Preferably, in the data analysis step, an amount of change in acceleration in the first cycle of predetermined time is calculated. The predetermined time is within 1.5 msec from the time of hitting. Preferably, the sport hitting toolhas the hitting section detachably attached to a shaft section.

Method for evaluating hit feeling

The evaluation method includes a first step, by using measurement means Mwhich can measure force F acting between a swing subject and the sport hitting tool or a specific directional component Fthereof, obtaining measured value Vf of the force F or the force Fat time after the impact, and a second step of determining the hit feeling on the basis of the measured value Vf at least at the one time. Preferably, the force F or the force Fis force Fs containing a component in a shear direction. Preferably, in the first step, the measured values Vf in a specific interval Zfrom time Tto Tafter the impact are obtained chronologically. Preferably, the evaluation is made based on a difference between a maximum value and a minimum value of the measured values Vf.

A valuation method of the present invention quantitatively estimates hit feeling of a sport hitting tool. The evaluation method includes: a first step of using a measuring means Mcapable of measuring forces F acting between a swing subject and the sport hitting tool or specific directional components Fthereof to obtain values of the forces F or the components Fat times after impact; and a second step of deciding the hit feeling based on the value of the force F or the component Fat at least one of the times. Preferably, the values of the forces F or the components Fin a specified period Zbetween a time Tand a time Tafter the impact are obtained in time series in the first step. Preferably, the hit feeling is evaluated based on an integrated value Sf of the forces F or the components Fin the specified period Zin the second step.

An object of the present invention is to improve the abrasion-resistance of a golf ball having a polyurethane cover. Another object of the present invention is to enhance the resilience and the shot feeling thereof. The present invention provides a golf ball having a cover, said cover comprising, as a base resin, a thermoplastic polyurethane containing a polycarbonate polyol as a constitutional component, wherein the polycarbonate polyol has, as a repeating constitutional unit, In Formula (I), Ris a bivalent residue obtained by removing two hydroxyl groups from a diol having 4 to 6 carbon atoms.  In Formula (II), Ris a bivalent residue obtained by removing two hydroxyl groups from a diol having 4 to 6 carbon atoms.

Golf ball

The present invention aims to improve spin performance and abrasion resistance for a golf ball having a cover using a nonionic polyurethane as a resin component. The golf ball of the present invention is a golf ball including a core and a cover covering the core and in which the cover contains a nonionic polyurethane as a resin component and the nonionic polyurethane has a hard segment content of 24.5% to 34.7% by mass.

An object of the present invention is to improve abrasion-resistance and spin performance of a golf ball having a polyurethane cover. The golf ball of the present invention is a golf ball having a core and a cover covering the core. The cover contains a layered silicate and a polyurethane resin having a secondary or a tertiary amine structure in a molecular chain thereof. In the present invention, the polyurethane resin used as a resin component constituting the cover has a secondary or tertiary amine structure in a molecular chain. Thus, it has a strong interaction with the layered silicate, and a reinforcing effect of the filler becomes even higher. As a result, abrasion-resistance and spin performance of the resultant cover are improved.

Golf ball and process for preparing the same

The object of the present invention is to provide a golf ball which is even more excellent in abrasion-resistance, durability and moldability by using a polyurethane ionomer having a novel structure as a base resin of a cover. The golf ball of the present invention has a cover, and the cover comprises, as a base resin, a polyurethane ionomer containing a polycarbonate polyol as a constitutional component.

An apparatus comprises a first camera (), a second camera () and a third camera (). The first camera () photographs a golf ball (B) from behind, the second camera () photographs the golf ball (B) from a head, and the third camera () photographs the golf ball (B) obliquely from ahead. At an early stage, position coordinates (x, z) of the golf ball (B) are calculated by a triangulation method from an angle of elevation of the golf ball (B) which is obtained by the first camera () and an angle of elevation of the golf ball (B) which is obtained by the second camera (). Within a range in which the direction of advance of the golf ball (B) is coincident with the optical axis of the second camera (), the position coordinates (x, z) of the golf ball (B) are calculated by the triangulation method from the angle of elevation of the golf ball (B) which is obtained by the first camera () and an angle of view of the golf ball (B) which is obtained by the third camera ().

Apparatus for measuring a trajectory

Golf ballhas multisurface dimples. The multisurface dimplehas a central concave faceand six inclined faces. The inclined faceextends obliquely upward from the edgeof the central concave faceup to the phantom sphere. Two multisurface dimplesare adjacent each other sharing a boundary lineon spherical surface interpositioned therebetween. Total length of the boundary linesthat exist at the site where multisurface dimplesare adjacent each other is equal to or less than 2400 mm. Proportion of the multisurface dimplesoccupied in total number of dimples is preferably equal to or greater than 70%. Proportion of the number of the boundary linesoccupied in the number of sites where multisurface dimplesare adjacent each other is equal to or greater than 70%.

A flying sphere is photographed twice at a predetermined time interval and two static images thus obtained are used to measure a rotation of the sphere through an image processing based on a recognition mark of a surface of the sphere. The recognition mark includes a central mark having a directivity and a rotating angle calculating mark provided to surround the central mark. The central mark includes a rectangle and a circle provided apart from the rectangle adjacent to one of short sides of the rectangle. Three or more rotating angle calculating marks are provided. Respective center positions of the rotating angle calculating marks are present in a region provided apart from a center position of the central mark by 13 mm to 17 mm.

Method of measuring rotation of sphere

A golf ball has a spherical surface provided with a plurality of dimples, a parting line extending on a great circle without crossing any of the dimples, and a first great circle, a second great circle and a third great circle dividing the spherical surface into eight spherical equilateral triangles, wherein the parting line crosses six of the eight spherical equilateral triangles, and with respect to each of the first to third great circles, the number of dimples on one side of the great circle is equal to the number of dimples on the other side of the great circle. Further, the golf ball may have the following features: with respect to any of two opposite equilateral triangles which are opposed about the center point of the spherical surface, the arrangement of dimples in one of them and the arrangement of dimples in the other are point-symmetrical about the center point; with respect to any of two adjacent spherical equilateral triangles which have a side in common, the arrangement of dimples in one of them and the arrangement of dimples in the other are not line-symmetrical about the common side; and with respect to any of four adjacent spherical equilateral triangles which have an apex in common, the arrangement of dimples in the four spherical equilateral triangles is not a point-symmetry about the common apex.

A cavity die ( ) has a flange part ( ), a body ( ), and a cavity surface ( ). An annular groove ( ) is formed on a periphery of the body ( ). A region surrounded with the annular groove ( ) and a retaining plate forms a boundary flow path. An inner flow path ( ) is formed inside the body ( ). The inner flow path ( ) is linear. Both ends of the inner flow path ( ) are open on a peripheral surface of the body ( ) to form openings ( ) thereon. A heating medium flows into the boundary flow path and the inner flow path ( ) through a flow path formed on the retaining plate. Thereby, the temperature of the cavity die ( ) is adjusted.

Golf ball-shaping mold and cavity die

The present invention provides a multi-piece solid golf ball having excellent flight performance and good shot feel at the time of hitting. The present invention relates to a multi-piece solid golf ball comprising a center having at least one layer, an intermediate layer formed on the center, and an outer layer covering the intermediate layer, wherein the center has a JIS-C hardness of 65 to 85, a surface hardness of the center is higher than a central point hardness of the center by not more than 10, a JIS-C hardness of the intermediate layer is lower than the surface hardness of the center by 0 to 10, a JIS-C hardness of the outer layer is higher than the hardness of the intermediate layer by 15 to 40.

Multi-piece solid golf ball

The present invention is directed to a multi-piece solid golf ball exhibiting excellent flight performance by optimizing the trajectory of the golf ball during flight. The golf ball of the present invention satisfies the formula 1020&lE;(NY&plus;266H)&lE;1085 with total number of dimples being N, the quotient Y being determined by dividing A by B in which A is the total area of a plane defined by a dimple edge and B is a surface area of a sphere when the sphere is formed assuming that there is no dimple on the cover, and a deformation amount H when applying from an initial load of 10 kgf to a final load of 130 kgf on the golf ball.

A golf ball that plural kinds of dimples are disposed on a spherical face, and a great circle zone not including even a part of the dimples are formed on the spherical face. An imaginary great circle line is drawn on the great circle zone, and two intersections of the spherical face and a straight line, which is at right angles with a circular plane of which circumference is the imaginary great circle line, and goes through the center of the golf ball, are poles. And, in a ball hemispherical face of which border is the imaginary great circle line, when the spherical face is equally divided with imaginary arc lines which start from the pole and are at right angles with the imaginary great circle line, dimple dispositions of adjacent divided areas sharing an imaginary arc line are not line-symmetric with respect to the imaginary arc line, and the dimple dispositions of the divided areas are rotation-symmetric with respect to the straight line.

Growing community of inventors

Kobe, Japan

Takeshi Asakura