Abstract: A golf club head having a hollow portion therein, the head includes a main body including a crown portion and a sole portion, and a face member forming at least a part of a striking face for striking a ball. The main body is made of a first material having a first specific gravity. The face member is formed of a second material having a second specific gravity smaller than the first specific gravity. The main body is provided with at least one slit that penetrates the main body, and the at least one slit extends in a head-front-back direction.

Abstract: A golf club head having a hollow portion therein, the head includes a face portion, and a main body including a crown portion and a sole portion each extending backwardly from the face portion. The main body is provided with at least one slit that penetrates the main body and extends in a head-front-back direction. The at least one slit includes a pair of slit inner walls extending in the head-front-back direction and at least one joint connecting the pair of slit inner walls to each other.

Abstract: A head 2 includes a head body h1, a face part Fp1, and a connecting part Cn1. The face part Fp1 includes a face surface f1 and a face back surface f2. The connecting part Cn1 connects the face back surface f2 of the face part Fp1 and the head body h1 to each other. The connecting part Cn1 may be provided at a position separated from a peripheral edge of the face back surface f2. The peripheral edge of the face back surface f2 may be separated from the head body h1. The face part Fp1 may include a face middle region R1 and a face peripheral region R2. The connecting part Cn1 may be provided only in the face middle region R1.

Abstract: A golf club head with a hollow therein comprises a face portion and a main body portion including a crown portion and a sole portion extending rearward from the face portion. The main body portion is provided with at least one slit penetrating through the main body portion. The slit has a width in the toe-heel direction and a length in the front-rear direction which is larger than the width. The surrounding area of the slit is at least partially provided with a thick portion.

Abstract: Provided is a sensor device-equipped golf shoes comprising: golf shoes including a left and right pair of a first shoe and a second shoe to be worn by a golfer; and a sensor device attached to the golf shoes. The sensor device includes one or more sensor modules configured to measure sensor data pertaining to at least one of an orientation of the first shoe when the golfer takes a shot, an orientation of the second shoe when the golfer takes a shot, and a positional relationship between the first shoe and the second shoe when the golfer takes a shot.

Abstract: A golf club head has a hollow therein and comprises a face portion, a crown portion and a sole portion. The face portion comprises a central zone including a face center, and a peripheral zone surrounding the central zone. Each of the central zone and the peripheral zone has a flexural stiffness defined by E×t3/12, wherein E is the Young's modulus (GPa) and t is the thickness (mm) of the zone concerned. The ratio sc/sp of the flexural stiffness Sc of the central zone to the flexural stiffness sp of the peripheral zone is 5.0 to 55.0.

Abstract: A golf club head is provided with a hollow therein and comprises a face portion, a crown portion, a sole portion, a toe and a heel. One of or each of a toe side and a heel side of the crown portion is provided with a first rigidity-decreasing part which is a groove or a slit and extends in a front-rear direction of the head.

Abstract: A golf ball 2 includes a core 4, an inner cover 6 positioned outside the core 4, and an outer cover 8 positioned outside the inner cover 6. The core 4 has a capsule 14, a plurality of separators 16, an electronic unit 18, and a plurality of fillings 20. The capsule 14 has a melting point of not lower than 100° C. A ratio P1 of a volume Vr of the capsule 14 to a volume Vc of the core 4 is not less than 25% and not greater than 75%. The electronic unit 18 is housed in the capsule 14. The electronic unit 18 detects behavior of the golf ball 2.

Abstract: A golf club head having a cavity therein comprises a wall at least a part of which is formed as a convexo-concave wall portion. The convexo-concave wall portion is composed of convexed portions repeatedly arranged in a first direction and a second direction intersecting the first direction, and concaved portions formed between the convexed portions. Each of the convexed portions includes at least one first protrusion extending in the first direction and at least one second protrusion extending in the second direction.

Abstract: A pressurizing device is used for manufacturing a fiber-reinforced resin pipe from a pipe-shaped laminate body prepreg sheets, and comprises a tubular main body. The tubular main body is provided with a helical cut extending helically in the axial direction so as to have a helical cut portion made of a metal. The helical cut portion is arranged inside or outside of the pipe-shaped laminate body. The helical cut portion changes its outer diameter and inner diameter to press the laminate body when a torsional moment and/or a force in the axial direction is applied thereto.

Abstract: Provided is an analysis apparatus for analyzing a behavior of a ball that has a center of gravity and in which an acceleration sensor is installed at a position shifted from the center of gravity by a predetermined shift amount, the analysis apparatus including a control unit configured to derive a centrifugal acceleration that is applied to the acceleration sensor, based on acceleration data that is output by the acceleration sensor, and derive at least one of a direction of a rotation axis and a rotation speed of a spin of the ball, based on the predetermined shift amount and the centrifugal acceleration.

Abstract: A golf club head has a hollow therein and comprises a face portion, a crown portion and a sole portion. The face portion comprises a central zone including a face center, and a peripheral zone surrounding the central zone. Each of the central zone and the peripheral zone has a flexural stiffness defined by E×t3/12, wherein E is the Young's modulus (GPa) and t is the thickness (mm) of the zone concerned. The ratio sc/sp of the flexural stiffness Sc of the central zone to the flexural stiffness sp of the peripheral zone is 5.0 to 55.0.

Abstract: Provided is a sensitive golf club with a sensor unit. The sensor unit includes a battery, a sensor module configured to measure sensor data indicating a state of the golf club using power from the battery, a communications unit configured to wirelessly transmit the sensor data to an external device using power from the battery, and a control unit configured to control operation of the sensor module and the communications unit using power from the battery. The sensor unit has an A mode, and a B mode in which operation of the communications unit is suppressed compared to the A mode. The control unit is configured to judge whether or not the golf club is prepared for a shot based on the sensor data, and switch between the A mode and B mode based on whether or not the golf club is prepared for a shot.

Abstract: A hollow golf club head comprises a face portion having a club face for hitting a ball, and a main body portion including a crown wall, a side wall and a sole wall which extend from the face portion toward the rear of the head. At least one of the walls of the main body portion is provided with a folded portion for facilitating a partial elastic deformation of the main body portion when the face portion hits a ball. The folded portion includes a first folded portion and a second folded portion each extending in the front-back direction of the head while swinging in the thickness direction of the wall. The first folded portion and the second folded portion are continuous with each other and extend along the peripheral edge of the club face, and have different phases in the swing.

Abstract: A golf club head having a cavity therein comprises a wall at least a part of which is formed as a convexo-concave wall portion. The convexo-concave wall portion is composed of convexed portions repeatedly arranged in a first direction and a second direction intersecting the first direction, and concaved portions formed between the convexed portions. Each of the convexed portions includes at least one first protrusion extending in the first direction and at least one second protrusion extending in the second direction.

Abstract: A golf club includes a head including a hosel part, a shaft, and a tip engagement part having a reverse-tapered shape and being disposed at a tip end portion of the shaft. The tip engagement part includes a sleeve having a reverse-tapered shape and being fixed to the tip end portion of the shaft. The hosel part includes a hosel hole. The hosel hole includes a reverse-tapered hole corresponding to at least a part of the outer surface of the tip engagement part. The tip engagement part is fitted to the reverse-tapered hole. Of the hosel hole, at least an upper end edge and a lower end edge are formed by a resin.

Abstract: This fitting method includes, for example, the following steps A1 to E1: (A1) a step of measuring a plurality of impact conditions using a reference club; (B1) a step of obtaining hit ball arrival point data; (C1) a step of selecting two or more of the plurality of impact conditions as explanation variables and performing multiple linear regression analysis with the hit ball arrival point data as an objective variable; (D1) a step of selecting a specific explanation variable from the two or more explanation variables based on a result of the multiple linear regression analysis; and (E1) a step of determining a recommended club including a specification capable of suppressing variation in the specific explanation variable.

Abstract: A hollow golf club head 1 comprises a face portion 2 which includes a club face 2a for striking a ball, and a main body 3 extending rearward of the head from the face portion 2. The face Portion 2 is made of a low-specific-gravity material having a specific gravity of 4.0 or less. The main body 3 is provided in its face portion 2 side with a low stiffness zone 10 where the stiffness is locally reduced.

Abstract: A golf club head includes a head body, a face part located apart from the head body, and a plurality of connecting parts that extend between the head body and the face part. Each connecting part includes an inclination portion that extends while inclining with respect to a face perpendicular direction. The inclination portion may include a straight inclination portion that extends along a straight line. The inclination portion may include an arc inclination portion that extends along a circular arc. The inclination portion may include a first inclination portion and a second inclination portion that are inclined inversely to each other. The inclination portion can facilitate deformation of the connecting part at impact.

Abstract: Provided is a method of evaluating stability of a golf swing. The method comprises calculating a force indicator that represents a force that acts on a body of a golfer during the golf swing and evaluating stability of the golf swing according to a magnitude of the force indicator. In the calculating, the force indicator may be calculated during the golf swing made with a specific golf club, and in the evaluating, the stability of the golf swing may be evaluated as a characteristic of the specific golf club, in accordance with the magnitude of the force indicator.