Abstract: According to the present invention, a torque applied from a golf player to a golf club during a swing is analyzed in a time-series manner. A DLT method is suitable as a determination procedure. Preferably, a link model is used in this analysis. Preferably, the three-dimensional coordinate of the mark provided at a position that corresponds to the link model is determined by a DLT method. Preferable analysis method includes: modeling using a golf club, and at least a part of a golf player who grips a grip member of the golf club to provide a link model in which the golf club is connected with the golf player via a joint; and analyzing the torque that acts on the joint is analyzed during the swing in a time-series manner. This joint is positioned in the vicinity of the grip member. This analysis can be applied to a method of diagnosing a swing, a method of selecting a golf club, and a method of designing a golf club.

Abstract: A golf club head which comprises a face, a crown, a sole, a sidewall extending from the periphery of the sole towards the crown excluding the face, and a neck to be fixed to a shaft, and the head is formed by welding together a face member for the face, a crown member for the crown and a walled sole member for forming at least the sole and the sidewall, wherein the walled sole member is made by monoblock casting, and the face member and the crown member are each made by plastic deformation processing.

Abstract: According to the present invention, a torque applied from a golf player to a golf club during a swing is analyzed in a time-series manner. A DLT method is suitable as a determination procedure. Preferably, a link model is used in this analysis. Preferably, the three-dimensional coordinate of the mark provided at a position that corresponds to the link model is determined by a DLT method. Preferable analysis method includes: modeling using a golf club, and at least a part of a golf player who grips a grip member of the golf club to provide a link model in which the golf club is connected with the golf player via a joint; and analyzing the torque that acts on the joint is analyzed during the swing in a time-series manner. This joint is positioned in the vicinity of the grip member. This analysis can be applied to a method of diagnosing a swing, a method of selecting a golf club, and a method of designing a golf club.

Abstract: Three moments of inertia M1, M2, and M3 (g·cm 2) about three axes defined in a golf putter are defined in a manner to provide a weight balance satisfying the expressions {(M1?M2)<12000} and {M1>M2>M3}.

Abstract: A hollow metal club head comprises a face portion whose front surface defines the club face, and a turnback wall extending backward from the circumferential edge of the face portion, wherein a head volume is in a range of not less than 440 cc, a height of the club face is in a range of from 55 to 85 mm, and a surface area of the club face is in a range of from 4000 to 6500 sq. mm. In a front end zone of the turnback wall and a peripheral zone of the face portion which are adjacent to each other through a junction between the turnback wall and the face portion, the ratio Rf/Rh of a zone rigidity Rf=(Ef×tf3) of the peripheral zone to a zone rigidity Rh=(Eh×th3) of the front end zone is in a range of from 4.0 to 12.0.

Abstract: A golf club head comprises a hollow body having a cavity, a plurality of rib-like walls provided on the inner surface of the hollow body so as to extend backward from a position near the face portion, and a sound bar disposed behind the face portion so as to extend along the back face of the face portion. A method of making a golf club head comprises making a wax model of the hollow main body having an opening, wherein in order to prevent deformation of the wax model during making a casting mold, the wax model is provided with a brace which extends across the opening and protruding walls which are disposed on the inner surface of the wax model and extend backwards from the opening.

Abstract: A golf club head which comprises a face, a crown, a sole, a sidewall extending from the periphery of the sole towards the crown excluding the face, and a neck to be fixed to a shaft, and the head is formed by welding together a face member for the face, a crown member for the crown and a walled sole member for forming at least the sole and the sidewall, wherein the walled sole member is made by monoblock casting, and the face member and the crown member are each made by plastic deformation processing.

Abstract: A golf club head comprises a face plate having a back face and a front face forming a club face for hitting a ball; a clubhead main body to which the face plate is attached, the clubhead main body comprising a sole portion and a backside wall portion, the backside wall portion extending upward from the sole portion, leaving a space from said back face; and an insert made of an elastic material and interposed between the back face of the face plate and the backside wall portion.

Abstract: A golf club head includes two metal parts which are connected each other by welding their opposite surfaces. A method of making the golf club head constitutes: making the two metal parts, wherein at least one of them is provided with a small protrusion along the surface to be welded; and laser welding the opposite surfaces by applying a laser beam to at least the protrusion so that the molten material of the protrusion penetrates into a gap between the opposite surfaces to connect the two metal parts.

Abstract: Three moments of inertia M1, M2, and M3 (g·cm 2) about three axes defined in a golf putter are defined in a manner to provide a weight balance satisfying the expressions {(M1?M2)<12000} and {M1>M2>M3}.

Abstract: A head (5) comprises a body (9), a face (11), a neck (13) and a crown (15). The crown (15) includes an outer plate (21) and an inner plate (23). The outer plate (21) and the inner plate (23) are opposed to each other with a gap provided therebetween. The outer plate (21) and the inner plate (23) are formed of a titanium alloy. The inner plate (23) has a projection (25). The upper end of the projection (25) abuts on the lower surface of the outer plate (21). The projection (25) and the outer plate (21) are bonded to each other by a spot welding method. The outer plate (21) and the inner plate (23) have thicknesses of 0.1 mm to 0.6 mm, respectively. The head (5) has a volume of 300 cm3 or more. A portion between the outer plate (21) and the inner plate (23) maybe filled with a synthetic resin.

Abstract: A golf club head comprises a hollow body having a cavity, a plurality of rib-like walls provided on the inner surface of the hollow body so as to extend backward from a position near the face portion, and a sound bar disposed behind the face portion so as to extend along the back face of the face portion. A method of making a golf club head comprises making a wax model of the hollow main body having an opening, wherein in order to prevent deformation of the wax model during making a casting mold, the wax model is provided with a brace which extends across the opening and protruding walls which are disposed on the inner surface of the wax model and extend backwards from the opening.

Abstract: A golf club head containing a hollow main frame and a face plate; the hollow main frame is composed of a main body and a crown plate welded to the main body, the main body containing a hosel part, a sole part and a side part extending upwards from the periphery of the sole part except for a front edge of the sole part thereby providing an open top and an open front, and the crown plate covers said open top, whereby the main frame has an opening on the front thereof. The face plate is welded to the main frame to cover the front opening of the main frame; the face plate includes a face part defining a clubface, and a flange part extending backward from at least the upper edge of the face part; the main frame further including eaves extending from an upper edge of the opening to the inside of the flange part, wherein the thickness of crown plate is in the range of 0.3 to 1.5 mm.

Abstract: A golf club head comprises a hollow body having a cavity, a plurality of rib-like walls provided on the inner surface of the hollow body so as to extend backward from a position near the face portion, and a sound bar disposed behind the face portion so as to extend along the back face of the face portion. A method of making a golf club head comprises making a wax model of the hollow main body having an opening, wherein in order to prevent deformation of the wax model during making a casting mold, the wax model is provided with a brace which extends across the opening and protruding walls which are disposed on the inner surface of the wax model and extend backwards from the opening.

Abstract: A hollow metal club head comprises a face portion whose front surface defines the club face, and a turnback wall extending backward from the circumferential edge of the face portion, wherein a head volume is in a range of not less than 440 cc, a height of the club face is in a range of from 55 to 85 mm, and a surface area of the club face is in a range of from 4000 to 6500 sq.mm. In a front end zone of the turnback wall and a peripheral zone of the face portion which are adjacent to each other through a junction between the turnback wall and the face portion, the ratio Rf/Rh of a zone rigidity Rf (=Ef×tf3) of the peripheral zone to a zone rigidity Rh (=Eh×th3) of the front end zone is in a range of from 4.0 to 12.

Abstract: A head (5) comprises a body (9), a face (11), a neck (13) and a crown (15). The crown (15) includes an outer plate (21) and an inner plate (23). The outer plate (21) and the inner plate (23) are opposed to each other with a gap provided therebetween. The outer plate (21) and the inner plate (23) are formed of a titanium alloy. The inner plate (23) has a projection (25). The upper end of the projection (25) abuts on the lower surface of the outer plate (21). The projection (25) and the outer plate (21) are bonded to each other by a spot welding method. The outer plate (21) and the inner plate (23) have thicknesses of 0.1 mm to 0.6 mm, respectively. The head (5) has a volume of 300 cm3 or more. A portion between the outer plate (21) and the inner plate (23) maybe filled with a synthetic resin.

Abstract: A golf club head comprises two metal parts which are connected each other by welding their opposite surfaces.

Abstract: A golf club head comprises a face plate having a back face and a front face forming a club face for hitting a ball; a clubhead main body to which the face plate is attached, the clubhead main body comprising a sole portion and a backside wall portion, the backside wall portion extending upward from the sole portion, leaving a space from said back face; and an insert made of an elastic material and interposed between the back face of the face plate and the backside wall portion.

Abstract: A metallic golf club head is provided on the inner surface of the crown portion and/or the inner surface of the sole portion with resonance controlling lines for improving ball hitting sounds, the resonance controlling lines protrude from the inner surface and extend substantially normally to the face portion.

Abstract: A golf club head comprises a hollow main frame and a face plate; the hollow main frame is composed of a main body and a crown plate welded to the main body, wherein the main body comprises a hosel part, a sole part and a side part extending upwards from the periphery of the sole part except for a front edge of the sole part thereby having an open top and an open front, and the crown plate covers said open top whereby the main frame has an opening on the front thereof; the face plate is welded to the main frame to cover the front opening the main frame; the face plate comprises a face part defining a clubface, and a flange part extending backward from at least an upper edge of the face part; the main frame further comprises an eaves extending from an upper edge of said opening to the inside of said flange part; and the thickness of crown plate is in a range of from 0.3 to 1.5 mm.