Abstract: A method for forming a golf ball provides a core member comprising a core of a golf ball into a cavity of a mold so that the core member is supported by a movable holding pin disposed in the mold; forming a layer outside the core member by injecting a material of the layer into the cavity; and retracting the pin from the cavity into the mold during the material injection so that a portion projecting from a surface of the layer is formed by a tip of the pin, the projecting portion having a site area of at least 0.2% in relation to an entire area of the tip of the pin and having a height of at least 0.2 mm. This method can be implemented by controlling the retraction of the pin, or alternatively by using the pin having a predetermined indentation portion on the tip.

Abstract: A method for forming a golf ball provides a core member comprising a core of a golf ball into a cavity of a mold so that the core member is supported by a movable holding pin disposed in the mold; forming a layer outside the core member by injecting a material of the layer into the cavity; and retracting the pin from the cavity into the mold during the material injection so that a portion projecting from a surface of the layer is formed by a tip of the pin, the projecting portion having a site area of at least 0.2% in relation to an entire area of the tip of the pin and having a height of at least 0.2 mm. This method can be implemented by controlling the retraction of the pin, or alternatively by using the pin having a predetermined indentation portion on the tip.

Abstract: A method for forming a golf ball provides a core member comprising a core of a golf ball into a cavity of a mold so that the core member is supported by a movable holding pin disposed in the mold; forming a layer outside the core member by injecting a material of the layer into the cavity; and retracting the pin from the cavity into the mold during the material injection so that a portion projecting from a surface of the layer is formed by a tip of the pin, the projecting portion having a site area of at least 0.2% in relation to an entire area of the tip of the pin and having a height of at least 0.2 mm. This method can be implemented by controlling the retraction of the pin, or alternatively by using the pin having a predetermined indentation portion on the tip.

Abstract: A golf ball trajectory prediction method that can predict the trajectory of a golf ball with high accuracy is provided. The golf ball trajectory prediction method includes: a swing measurement step of measuring a golfer's swing using a test golf club; a head behavior prediction step of predicting a behavior of a head of a target golf club when using the target golf club, with a measurement value of the swing measured in the swing measurement step as input; a ball initial behavior calculation step of calculating an initial behavior of a golf ball after colliding with the head of the golf club, based on the behavior of the head predicted in the head behavior prediction step; and a ball trajectory prediction step of predicting a trajectory of the golf ball, from the initial behavior of the golf ball calculated in the ball initial behavior calculation step.

Abstract: A measurement apparatus includes a first Doppler sensor which outputs a first transmission signal and receives a first Doppler signal, that is the first transmission signal returned after being reflected by an impacting object, a timing detection unit that detects an impact timing which is a moment when an impacted object is impacted by the impacting object, an impacting object speed computing unit that computes a speed of the impacting object based on the first Doppler signals obtained from the detected impact timing to a timing before a predetermined period, and an imaging unit that images the impacted object immediately after the impact so as to be used for computing a motion state of the impacted object, based on the computed speed of the impacting object.

Abstract: A method for forming a golf ball provides a core member comprising a core of a golf ball into a cavity of a mold so that the core member is supported by a movable holding pin disposed in the mold; forming a layer outside the core member by injecting a material of the layer into the cavity; and retracting the pin from the cavity into the mold during the material injection so that a portion projecting from a surface of the layer is formed by a tip of the pin, the projecting portion having a site area of at least 0.2% in relation to an entire area of the tip of the pin and having a height of at least 0.2 mm. This method can be implemented by controlling the retraction of the pin, or alternatively by using the pin having a predetermined indentation portion on the tip.

Abstract: A measurement apparatus includes a first Doppler sensor which outputs a first transmission signal and receives a first Doppler signal, that is the first transmission signal returned after being reflected by an impacting object, a timing detection unit that detects an impact timing which is a moment when an impacted object is impacted by the impacting object, an impacting object speed computing unit that computes a speed of the impacting object based on the first Doppler signals obtained from the detected impact timing to a timing before a predetermined period, and an imaging unit that images the impacted object immediately after the impact so as to be used for computing a motion state of the impacted object, based on the computed speed of the impacting object.

Abstract: A golf ball has a multiplicity of dimples formed in its surface. It is assumed that the ball has a phantom sphere and spherical surface when the ball surface is free of dimples. A tangent angle .theta. is 5.degree..ltoreq..theta..ltoreq.20.degree. wherein .theta. is defined between a tangent at an arbitrary point on an edge of an individual dimple to the phantom spherical surface and a tangent at that point to the actual ball surface. A percent dimple volume Vr is 0.8%.ltoreq.Vr.ltoreq.1.1% wherein Vr is the sum of the volumes of the entire dimples divided by the volume of the phantom sphere. This dimple design prevents lowering of spin susceptibility by repetitive hits without detracting from the dimple effect of increasing flight distance.