Bridgestone Sports Co., Ltd.

K. K. Endo Seisakushao

Masafumi Nishitani

Koki Motoyoshi

Atsuo Tateno

Makoto Kubota

Hisashi Yamagishi

Hideo Matsunaga

Masaei Tsurumaki

A golf club head is a hollow head made of metal, preferably titanium or a titanium alloy. The golf club head has a face portion, a crown portion, a sole portion, a side portion, and a hosel portion. A thin and small plate made of metal is fixedly attached to the internal surface of the sole portion on the toe side so as to be in tight contact with the internal surface. The thin and small plate made of metal preferably has a thickness of 0.2 mm-1.2 mm, particularly 0.4 mm-1.1 mm, more particularly 0.5 mm-1.0 mm, and a weight of 0.5 g-1.5 g, particularly 0.6 g-1.0 g.

Golf club head

An iron-type golf club head has a face which has a face surface of a flat shape, and a hosel which is continuous with the face on its heel side. A shaft insertion hole is disposed in the hosel. A protrusion protruding rearward is disposed in the vicinity of the center in a toe-heel direction. A material of the golf club head is pure iron having a high purity of at least 99.8%, for instance, pure iron having a purity within a range of 99.995 to 99.9999%. The golf club head is subjected to carburizing so that carbon diffuses up to about 0.2 to 0.5 mm from the surface. A region within 0.2 mm from the face surface has a hardness of HV 300 to 600, and a region where a distance from the face surface is 0.7 mm or more has a hardness of HV 100 or lower.

A weight material is provided on a heel side of a hosel portion in a golf club head. A convex portion E is provided on the heel side of the head. The weight material is disposed within the convex portion. The weight material is made of high specific gravity metal such as tungsten, and welded on both a lower column and a skirt portion.

A golf club includes a shaft and a metal head attached to the shaft. The metal head includes a plurality of metal pieces fixed together by means of laser welding. For example, a face member of the head is manufactured by laser welding three metal pieces; i.e., a center metal piece, an intermediate metal piece, and an outer metal piece.

Golf club

A golf club head includes a front body, a middle body, a back body integrally. The middle body is disposed between the front body and the back body. The middle body includes a middle crown constituting a middle portion of a crown portion in back and forth directions, a middle side constituting middle portions of both side surfaces on a toe side and a heel side in the back and forth directions, a middle sole constituting a middle portion of a sole portion in the back and forth directions. The middle body may include aluminum alloy. The front body and the back body may include titanium alloy.

Trapezoid-shaped portion of a rear surface of a golf club head

A golf club head has a head body, filler fixedly attached to the head bodyby press fitting into a recess portion of the head body, and a back weight disposed on the rear surface side of the filler and fixedly attached to a sole portion of the head body. Titanium, titanium alloys, aluminum, aluminum alloys and magnesium alloys are preferable as the filler. The back weight may be made of the same material as the head body or may be made of metal higher in specific gravity than the head body.

Growing community of inventors

Tokyo, Japan

Masafumi Nishitani