Abstract: A head body of a golf club head has a hollow portion defined by an outer wall. An opening portion is provided in a part of the head body. A small tungsten alloy piece having a shape fittable to the opening portion so as to cover the opening portion is fixedly attached to the opening portion by welding. The golf club head defines the opening portion in a part of the metal head body and has the small tungsten alloy piece fitted and joined to the opening portion by welding so that the golf club head can be reduced in weight because of provision of the hollow portion. Since the small tungsten alloy piece is joined to the opening portion by welding, difficult plastic forming is not required particularly, and the weight can be adjusted easily and accurately.

Abstract: A head body of a golf club head has a hollow portion defined by an outer wall. An opening portion is provided in a part of the head body. A small tungsten alloy piece having a shape fittable to the opening portion so as to cover the opening portion is fixedly attached to the opening portion by welding. The golf club head defines the opening portion in a part of the metal head body and has the small tungsten alloy piece fitted and joined to the opening portion by welding so that the golf club head can be reduced in weight because of provision of the hollow portion. Since the small tungsten alloy piece is joined to the opening portion by welding, difficult plastic forming is not required particularly, and the weight can be adjusted easily and accurately.

Abstract: The present invention makes it possible, in an HST drive circuit wherein an HST pump and an HST motor have been separately stored in a pump case and a motor case, to efficiently cool the HST drive circuit. A cooling line for, while discharging a relief oil from a charge circuit 9 for replenishing an HST closed circuit 5 with a pressure oil into a pump case 3, making the discharged oil flow into a reservoir 7 through the pump case 3, a communicating pipe 14, a motor case 4, and an oil cooler 16 is formed, so that hydraulic oil circulating through an HST pump 1, an HST motor 2, and the HST closed circuit 5 is cooled by an oil flowing through the cooling line.

Abstract: This invention provides a hollow golf club head having a face portion, a crown portion, a sole portion, and a side portion, and comprising a viscoelastic body to be mounted in at least one of the face portion, crown portion, sole portion, and side portion. The viscoelastic body is mounted in a part of a portion where the viscoelastic body is to be mounted, the part corresponding to an antinode of a primary vibration mode.

Abstract: A golf club head that includes: a pedestal composed of at least two ribs each having convex portions at both ends and formed on an inner face of the head; a metal weight disposed on the ribs; and a weld bead extending on a surface of the weight between the convex portions, the weight being fixed on the inner face of the head by the weld bead.

Abstract: This invention provides a hollow golf club head having a first viscoelastic body made of a first viscoelastic material and a second viscoelastic body made of a second viscoelastic material with a loss coefficient the temperature dependence of which is different from that of a loss coefficient of the first viscoelastic material.

Abstract: This invention provides a hollow golf club head having a viscoelastic body, wherein the viscoelastic body is made by mixing a plurality of types of viscoelastic materials with loss coefficients the temperature dependences of which are different.

Abstract: This invention provides a golf club head comprising a head main body, a face plate fixed to a front surface side of the head main body to form a face surface, a cavity portion formed in the head main body and open to a face plate side, and a viscoelastic body inserted in a compressed state in a space formed by the cavity portion and the face plate. An end face on the face plate side of a circumferential wall defining the cavity portion comprises a contacting portion ontacting with a rear surface of the face plate, and a non-contacting portion spaced apart from the rear surface of the face plate to form a gap communicating with the cavity portion between the non-contacting portion and the rear surface of the face plate.

Abstract: This invention provides a golf club head having a viscoelastic body, wherein the viscoelastic body is made by mixing a plurality of types of viscoelastic materials with loss coefficients temperature dependences of which are different.

Abstract: This invention provides a hollow golf club head including a fixing member which includes a shaft body formed with a threaded portion at one end, and a head portion at the other end of the shaft body, a viscoelastic body having an opening through which the shaft body extends, a recess portion formed in a circumferential wall of the golf club head and in which the viscoelastic body is disposed, and a screw hole formed in a bottom portion of the recess portion and threadably engages with the threaded portion. The viscoelastic body is fixed between the head portion and the bottom portion by threadably engaging the threaded portion with the screw hole.

Abstract: This invention provides a golf club head having a first viscoelastic body made of a first viscoelastic material and a second viscoelastic body made of a second viscoelastic material with a loss coefficient the temperature dependence of which is different from that of a loss coefficient of the first viscoelastic material.

Abstract: A wood-type golf club head includes a metal sole portion, an elastic body and a weight member. At least one recess is defined in the metal sole portion to extend in a front-rear direction over at least half-length of a front-rear length of the sole portion. The elastic body is embedded in the recess. The weight member is fixed to the recess to cover the elastic body. The weight member is flush with the sole portion. A total area of the recess is in a range of 10% to 60% of that of the sole portion.

Abstract: The present invention makes it possible, in an HST drive circuit wherein an HST pump and an HST motor have been separately stored in a pump case and a motor case, to efficiently cool the HST drive circuit. A cooling line for, while discharging a relief oil from a charge circuit 9 for replenishing an HST closed circuit 5 with a pressure oil into a pump case 3, making the discharged oil flow into a reservoir 7 through the pump case 3, a communicating pipe 14, a motor case 4, and an oil cooler 16 is formed, so that hydraulic oil circulating through an HST pump 1, an HST motor 2, and the HST closed circuit 5 is cooled by an oil flowing through the cooling line.

Abstract: A head body of a golf club head has a hollow portion defined by an outer wall. An opening portion is provided in a part of the head body. A small tungsten alloy piece having a shape fittable to the opening portion so as to cover the opening portion is fixedly attached to the opening portion by welding. The golf club head defines the opening portion in a part of the metal head body and has the small tungsten alloy piece fitted and joined to the opening portion by welding so that the golf club head can be reduced in weight because of provision of the hollow portion. Since the small tungsten alloy piece is joined to the opening portion by welding, difficult plastic forming is not required particularly, and the weight can be adjusted easily and accurately.

Abstract: A head body of a golf club head has a hollow portion defined by an outer wall. An opening portion is provided in a part of the head body. A small tungsten alloy piece having a shape fittable to the opening portion so as to cover the opening portion is fixedly attached to the opening portion by welding. The golf club head defines the opening portion in a part of the metal head body and has the small tungsten alloy piece fitted and joined to the opening portion by welding so that the golf club head can be reduced in weight because of provision of the hollow portion. Since the small tungsten alloy piece is joined to the opening portion by welding, difficult plastic forming is not required particularly, and the weight can be adjusted easily and accurately.

Abstract: An iron type golf club head including a face portion having a planar face surface, and a hosel portion connected to the heel side of the face portion. A shaft insertion hole is provided in the hosel portion so as to penetrate the hosel portion. The distance from the center of gravity is 28-33 mm, the height of the center of gravity is 12-21 mm, the depth of the center of gravity is 5-15 mm, and the goose distance is 4-15 mm.

Abstract: 4-Hydroxy-5-methyl-2,3-Dihydrofuran-3-one is produced by Maillard reaction between xylose, ribose or arabinose with glutamic acid, aspartic acid, alanine, glycine, proline or salts of these amino acids, and may be recovered in crystalline form from the reaction mixture by steam distillation, evaporation of the distillate at temperatures not higher than 40.degree. C, and sublimation from the oily residue at or above 80.degree. C. The compound imparts a pleasant maltol-like flavor to ingestible products such as food, drinks, but also compositions for oral hygiene. The crude Maillard reaction mixture containing the compound may be employed as a flavoring if prepared from glutamic acid, aspartic acid or their salts and from xylose or xylan.