Sumitomo Rubber Industries Limited

Dunlop Sports Company Limited

Yosuke Yamamoto

Kuniyasu Horiuchi

Kohei Mimura

Hironori Takihara

Atsuko Mitsuba

Fumiya Suzuki

Naoka Sakamoto

Tennis racket frame

A tennis racket includes a frame and a grommet. The frame includes a grommet groove, a small groove, and a hole. The small groove is recessed from the grommet groove. The grommet includes a base and a pipe. In a state where the grommet is attached to the frame, the base is accommodated in the grommet groove, and the pipe extends through the hole. The base is not positioned inside the small groove. Therefore, at the back of a back side surface of the base, there is a space derived from the small groove.

Racket

A grommet of a racket includes a tubular portion. The tubular portion has a through hole through which a string is passed. The through hole has a base-side opening, a side wall, and a tip-side opening. In the tip-side opening, an inner dimension in a direction parallel to a face is larger than an inner dimension in a direction perpendicular to the face. In the tubular portion, the string is in contact with the side wall from the base-side opening to the tip-side opening.

Tennis racket

In a tennis racket, longitudinal strings extending in a longitudinal direction and transverse strings extending in a transverse direction intersect each other to form a plurality of meshes. At a center, in the transverse direction, of a head, a ratio of an area St of a tip mesh located closest to a tip in the longitudinal direction relative to an area Sc of a center mesh located at a center in the longitudinal direction is not less than. The center mesh is formed in a rectangular shape having short sides in the longitudinal direction and long sides in the transverse direction. Preferably, from the center mesh to the tip mesh, an area of each mesh is set so as to be not larger than an area of a mesh adjacent thereto at a tip side.

Provided is a racket frame on which design change can be easily performed by simple processing. The racket frame includes a head formed in a ring shape along a face. On the head, a gut groove in which a base portion for connecting grommets is to be inserted is formed in a radially outer region of the head so as to be recessed toward a radially inner side, and a deformation promotion groove is formed in the radially outer region of the head so as to be recessed toward the radially inner side.

Racket frame

A racket frame has an inner thick part () having an outer surface (), an inner surface () and a pair of middle surfaces () each positioned between the outer surface () and the inner surface (). A thickness (Ti) of the inner surface () is greater than a thickness (To) of the outer surface (). A thickness of the inner thick part () gradually increases toward the inside. Consequently, the middle surface () is inclined with respect to an X direction. A distance (Ld) between an outer end and an inner end in a thickness direction of the middle surface () is equal to or greater than 0.5 mm.

A tennis racket fitting method according to the present invention comprises: a first step of preparing a plurality of test tennis rackets, at least one type of racket property that influences swing for hitting a ball being defined for each of the test tennis rackets; a second step of causing a reference tennis racket to be swung at least one time by a user in order to hit a tennis ball, and acquiring a measured value by measuring transition in at least one of the position, the velocity, the acceleration, and the angular velocity of the reference tennis racket in at least a portion of an interval from when the swing starts until when the swing ends; a third step of calculating at least one evaluation indicator to be an evaluation of the swing of the reference tennis racket based on the measured value; and a fourth step of, based on the racket property, selecting a tennis racket that can improve at least one evaluation indicator from among the test tennis rackets.

Method and computer-readable storage medium for fitting tennis racket and analysis device

In a racket frame, stoppersare each located on a tip side of a narrow diameter portionprotruding from a side of an inner circumferential surfaceof a head. A steel sheetsis fixed on the side of the inner circumferential surfaceopposing the stoppersvia the narrow diameter portion. Weightseach include a magnet sheet. The narrow diameter portionis inserted through notchesandof the weights. The steel sheetsand the magnet sheetare bound with magnetic force. The notchesandof the weightsare locked to a string protecting member. The stoppersprevent the weightsfrom being detached form the head. The weightsare detachably mounted on the head

A swing analyzing apparatus includes: a three-axis acceleration sensor attached to a tennis racket, for measuring accelerations in the directions of three axes when a swing for hitting a tennis ball is taken with the tennis racket; a three-axis gyro sensor attached to the tennis racket, for measuring angular speeds about the three axes; and an analyzing device. The analyzing device has a receiving function to receive data regarding the accelerations and the angular speeds from the three-axis acceleration sensor and the three-axis gyro sensor; a coordinate axis conversion function to convert relative coordinate axes that are the three axes for the accelerations into absolute coordinate axes on the basis of the angular speeds; and a calculation function to calculate an index of the swing on the basis of accelerations resulting from the coordinate axis conversion.

Tennis swing analysis method

A tennis swing movement analyzing apparatus of the present invention includes an acquisition unit configured to acquire sampling data obtained by sampling a swing movement of a tennis racket by a user; a calculation unit configured to, based on the sampling data, calculate an indicator selected from among the velocity, the acceleration, the angular velocity, and the position of the tennis racket or a ball hit by the tennis racket and an arbitrary combination thereof; and a screen creation unit configured to create a GUI screen displaying a graph area that is divided into a plurality of areas respectively indicating types of swings and displaying the indicator in the graph area.

Device, system, method and computer-readable storage medium for analyzing tennis swing motion

A racket frameincludes a head, a shaft, and a pair of throatsextending from the headto the shaft. A flexural rigidity Gof the throatsin a low load range (from 5 kgf to 15 kgf) is equal to or greater than 600 kgf/mm but equal to or less than 900 kgf/mm. A flexural rigidity Gof the throatsin a high load range (from 45 kgf to 55 kgf) is equal to or greater than 900 kgf/mm but equal to or less than 1200 kgf/mm. A rigidity ratio (G/G) of the flexural rigidity Gand the flexural rigidity Gis equal to or greater than 0.70 but equal to or less than 0.85.

A racket frameincludes a bodyand a first vibration-damping portionfixed to the body. The bodyincludes a head, a shaft, a pair of throatsextending from the headto the shaft, and a gripconnected to the shaft. The bodyincludes a second vibration-damping portion, and the material of the second vibration-damping portionis different from the material of the first vibration-damping portion. The ratio (R/R) of a side pressure rigidity Rto a throat rigidity Ris 0.26 or greater, a moment of inertia around an axis at a position of 10 cm from a grip end is less than 300 kg&#xb7;cm, and a vibration damping rate in an out-of-plane secondary mode is equal to or greater than 0.70 but equal to or less than 1.0.

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Kobe, Japan

Yosuke Yamamoto