GOLF CLUB HEAD

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to Japanese Patent Application No. 2023-214312 filed on Dec. 19, 2023. The entire contents of this Japanese Patent Application are hereby incorporated by reference.

BACKGROUND
Technical Field

The present disclosure relates to golf club heads.

Description of the Related Art

JP2020-178933A discloses a golf club head that includes a head body, a face plate fixed to the head body, and a weight member having a specific gravity greater than that of the head body and that of the face plate.

SUMMARY

The center of gravity of a golf club head can be lowered by allocating more weight to a lower portion of the head, for example, by disposing a weight member in the lower portion. On the other hand, when more weight is allocated in the lower portion of a head, the wall thickness of the lower portion of the head is increased, and the rebound performance of the head in hitting at a lower hit point tends to deteriorate. The term “hitting at a lower hit point” means a shot in which the hit point is located in a lower portion of the striking face.

One of the objects of the present disclosure is to provide a golf club head capable of lowering the head center of gravity and having an excellent rebound performance in hitting at a lower hit point.

In one aspect, a golf club head includes a striking face and a sole surface. The golf club head includes a face portion including the striking face, a body portion, and a weight member disposed in the body portion. The body portion includes a weight receiving portion on which the weight member is disposed. The weight member is coupled to the weight receiving portion. A toe-heel directional length of the weight member is greater than a top-sole directional length of the weight member. The body portion includes a sole thin-wall portion whose outer surface constitutes a part of the sole surface and that has a wall thickness of greater than or equal to 0.8 mm and less than or equal to 4.6 mm. An inner surface of the sole thin-wall portion includes: a weight contact surface that constitutes a part of the weight receiving portion and is in contact with the weight member; and a space facing surface that is located on a face side of the weight contact surface and faces an empty space. The weight member is not exposed outside the golf club head.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a golf club head according to a first embodiment as viewed from the front of its striking face;

FIG. 2 is the same drawing as FIG. 1, but also shows hidden lines with dashed lines;

FIG. 3 is a back view of the head in FIG. 1 as viewed from its back side;

FIG. 4 is an exploded perspective view of the head in FIG. 1;

FIG. 5 shows a body member of the head in FIG. 1 as viewed from the same viewpoint as in FIG. 1;

FIG. 6 is a cross-sectional view taken along line A-A in FIG. 1;

FIG. 7 is a cross-sectional view of the body member in FIG. 6;

FIG. 8 is the same cross-sectional view as FIG. 6, and a coupling member is added in FIG. 8;

FIG. 9 shows a golf club head according to a second embodiment as viewed from the front of its striking face;

FIG. 10 shows a golf club head according to a third embodiment as viewed from the front of its striking face;

FIG. 11 shows a golf club head of Comparative Example as viewed from the front of its striking face; and

FIG. 12 is a conceptual diagram for illustrating a reference state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present disclosure will be described in detail according to preferred embodiments with appropriate references to the accompanying drawings. In the following embodiments, the same or common elements are denoted by the same reference symbols, and duplicated explanations will be omitted as appropriate.

The following terms are defined in the present disclosure.

[Reference State]

In a head having a flat striking face such as an iron type head, the reference state is a state where a head is placed on a ground plane HP in a state where score lines and the ground plane HP are parallel to each other. In a head having a curved striking face such as a wood type head, the reference state is a state where a head is placed at a predetermined lie angle on the ground plane HP. In these reference states, the center line Z of a hosel hole (shaft axis line Z) of the head lies on (is contained in) a perpendicular plane VP (see FIG. 12). The perpendicular plane VP is a plane perpendicular to the ground plane HP.

In a head having a curved striking face, its face angle is 0° when the head is in the reference state. That is, in a planar view of a head as viewed from above, a line normal to its striking face at the geometric center of the striking face is set to be perpendicular to an intersection line NL. The intersection line NL is an intersection line between the perpendicular plane VP and the ground plane HP. When the head has a flat striking face, the intersection line NL is parallel to score lines.

There has been known a club including a changing mechanism in which its loft angle, lie angle and face angle can be adjusted by changing a rotational position of a sleeve or the like provided at a tip portion of a shaft. In a head used for such clubs, the shaft axis line Z of the head which is in the reference state is determined in a state where all adjustable items are set to be neutral. The term “neutral” means the center of the range of adjustment.

[Toe-Heel Direction]

The toe-heel direction is the direction of the intersection line NL. In a head having a flat striking face, the toe-heel direction is parallel to score lines.

[Face-Back Direction]

The face-back direction is the direction of a normal line that is normal to a striking face at its face center. In a head having a flat striking face, the face-back direction is perpendicular to the striking face.

[Top-Sole Direction]

The top-sole direction is the direction of an intersection line between the striking face and a plane perpendicular to the toe-heel direction. Accordingly, the top-sole direction is parallel to the striking face. In a head having a non-flat striking face, a tangent plane that is a flat plane tangent to the striking face at its face center can be used instead of the striking face. That is, the top-sole direction can be the direction of an intersection line between the tangent plane and the plane perpendicular to the toe-heel direction.

[Toe Reference Position]

A plurality of score lines have their respective toe-side ends. A toe-most position of the toe-side ends is the toe reference position (see toe reference position Pt in FIG. 1). As with the embodiment of FIG. 1, in a normal iron type golf club head, positions of the toe-side ends of all the score lines coincide with each other and are the toe reference position. The toe reference position is a position in the toe-heel direction. There is known an iron type head having a striking face in which score lines are formed on almost the entirety of the striking face. Such a configuration is mainly adopted in wedges, and is referred to as full score lines. In a head having full score lines, the toe reference position is a position that is spaced 18.5 mm apart from a toe-most point of the head toward the heel side. The distance 18.5 mm is measured in the toe-heel direction.

[Heel Reference Position]

The score lines have their respective heel-side ends. A heel-most position of the heel-side ends is the heel reference position (see heel reference position Ph in FIG. 1). In a normal iron type golf club head, the position of the heel-side end of a longest score line coincides with the heel reference position. The heel reference position is a position in the toe-heel direction.

[Score Line Center Position]

A position that divides a distance between the toe reference position and the heel reference position into two equal parts is defined as the score line center position (see score line center position Pc in FIG. 1). In a normal iron type golf club head, the center position of the longest score line coincides with the score line center position. The score line center position is a position in the toe-heel direction.

[Toe Middle Position]

A position that divides a distance between the toe reference position and the score line center position into two equal parts is defined as the toe middle position (see toe middle position Pt1 in FIG. 1). The toe middle position is a position in the toe-heel direction.

[Heel Middle Position]

A position that divides a distance between the heel reference position and the score line center position into two equal parts is defined as the heel middle position (see heel middle position Ph1 in FIG. 1). The heel middle position is a position in the toe-heel direction.

[Vertical Cross Section]

The vertical cross section is a cross section taken in the face-back direction and in the top-sole direction. In other words, the vertical cross section is a cross section taken along a plane perpendicular to the toe-heel direction. The vertical cross section can be set at each position in the toe-heel direction.

[Leading Edge]

In a vertical cross section of a head, a point located at the front-most position in the front-rear direction is determined. This point is the face-most position in the face-back direction. This point is determined in each of vertical cross sections taken at different positions in the toe-heel direction. A set of the points is defined as the leading edge. The leading edge can be the front edge of a sole surface.

[Trailing Edge]

When a radius of curvature of a sole surface is sequentially measured rearward in a vertical cross section of a head, a point at which the radius of curvature becomes first less than or equal to 5 mm is determined. A set of the points is defined as the trailing edge. The trailing edge can be the rear edge of the sole surface.

[Face Center]

On the score line center position, a point that divides the width of the striking face into two equal parts is defined as the face center (see face center Fc in FIG. 1). In a head in which the score line center position cannot be appropriately determined, a geometric center (center of figure) of the striking face in the planar view can be determined as the face center.

FIG. 1 shows a golf club head 100 according to a first embodiment as viewed from the front of its striking face. FIG. 2. is the same drawing as FIG. 1, but also shows the line of a weight member W1 which is hidden by a face portion with dashed line. FIG. 3 is a back view of the head 100 as viewed from the back side. FIG. 4 is an exploded perspective view of the head 100. FIG. 5 is a front view of a body member B1. FIG. 6 is a cross-sectional view taken along line A-A in FIG. 1. FIG. 7 is a cross-sectional view of the body member B1 taken along line A-A in FIG. 1.

The head 100 includes a striking face 102, a sole surface 104, a back surface 106, a top surface 108, and a hosel 110. The striking face 102 is a portion brought into contact with a ball in a shot. In the present embodiment which is an iron type head, a flat portion is the striking face 102. The sole surface 104 constitutes the lower surface of the head 100. The top surface 108 constitutes the upper surface of the head 100. The hosel 110 has a hosel hole 112. The hosel hole 112 has a center line Z. A shaft (not shown in the drawings) is attached to the hosel hole 112. When the head 100 is a wood type head or a hybrid type head, the top surface 108 corresponds to its crown surface. In the outer surface of the head 100, the back surface 106 constitutes a surface between the sole surface 104 and the top surface 108. When the head 100 is a wood type head or a hybrid type head, the back surface 106 is not present.

As shown in FIG. 3, the head 100 includes a leading edge Le and a trailing edge Te. The sole surface 104 includes a ridgeline 114 that extends from the toe side to the heel side. The ridgeline 114 is located between the leading edge Le and the trailing edge Te.

As shown in FIG. 1, the striking face 102 includes a plurality of score lines gv. The score lines gv include a longest score line gv1. Of the score lines gv, a score line having a longest length in the toe-heel direction is the longest score line gv1.

As shown in FIG. 1, the striking face 102 includes a face center Fc as defined above. As shown in FIG. 6, the striking face 102 includes a sweet spot SS. The sweet spot SS is an intersection point between the striking face 102 and a straight line L1 that passes the center of gravity G1 of the head 100 and is perpendicular to the striking face 102. Note that FIG. 6 does not mean that the sweet spot ss and/or the head center of gravity G1 is necessarily present on the cross section of FIG. 6.

The head 100 is an iron type head. In an iron type head, the striking face 102 is a flat surface except for the score lines gv. As shown in FIG. 6, the head 100 has a hollow structure. The head 100 includes a hollow interior 116 inside thereof. Such head 100 is also referred to as a hollow iron head. Alternatively, the head 100 does not have to be a hollow head. The head 100 may be a cavity back iron head that has a back cavity on the back side thereof, or a muscle back iron head that does not have a back cavity. The iron type head includes an iron type hybrid head. When the head 100 is an iron type head, the club number of the head 100 is not limited.

The head 100 does not have to be an iron type head. The head 100 may be a wood type head, a hybrid type head, or a putter type head. The striking face 102 does not have to be a flat surface.

From the viewpoint of configuration, the head 100 includes a face portion fp1, a body portion bp1, and the weight member W1.

The face portion fp1 includes the striking face 102. The striking face 102 constitutes the outer surface of the face portion fp1. The face portion fp1 includes a face back surface 103. The face back surface 103 constitutes the inner surface of the face portion fp1. The face back surface 103 is a surface opposite to the striking face 102. The face back surface 103 faces the hollow interior 116. The face portion fp1 can be a portion whose outer surface is the striking face 102 and whose inner surface is the face back surface 103. At least a part of the face portion fp1 and at least a part of the body portion bp1 may be included in an integrally-formed single-piece member.

The body portion bp1 is located on the back side of the face portion fp1. The body portion bp1 includes the sole surface 104, the back surface 106, and the top surface 108. The body portion bp1 includes the entirety of the sole surface 104. The body portion bp1 includes the entirety of the back surface 106. The body portion bp1 may include a part of the striking face 102. In the head 100, a portion other than the face portion fp1 can be the body portion bp1. At least a part of the body portion bp1 and at least a part of the face portion fp1 may be included in an integrally-formed single-piece member.

From the viewpoint of constituent members, the head 100 includes a face member F1, the body member B1, and the weight member W1 (see FIG. 4). The face member F1 is separately formed from the body member B1. The body member B1 is separately formed from the face member F1. The head 100 is formed by coupling the face member F1 and the body member B1.

The face member F1 includes at least a part of the striking face 102. In the present embodiment, the face member F1 includes the entirety of the striking face 102. All the score lines gv are formed on the face member F1. The face member F1 includes at least a part of the face back surface 103. In the present embodiment, the face member F1 includes the entirety of the face back surface 103. The face member F1 includes at least a part of the face portion fp1. In the present embodiment, the face member F1 includes the entirety of the face portion fp1. The face member F1 may be integrally formed as a single-piece member, or may be formed by coupling a plurality of members.

In the present embodiment, the face member F1 is a plate-shaped member. The configuration (shape) of the face member F1 is not limited. For example, the face member F1 may include a main portion that constitutes the striking face 102, a top-side extending portion that extends backward from the top-side edge of the main portion, and a sole-side extending portion that extends backward from the sole-side edge of the main portion. Such face member F1 may be referred to as a cup face. In this case, the top-side extending portion and the sole-side extending portion of the face member F1 can constitute a part of the body portion bp1.

The body member B1 includes at least a part of the sole surface 104. In the present embodiment, the body member B1 includes the entirety of the sole surface 104. The body member B1 includes at least a part of the back surface 106. In the present embodiment, the body member B1 includes the entirety of the back surface 106. The body member B1 includes at least a part of the top surface 108. In the present embodiment, the body member B1 includes a part of the top surface 108. The remaining part of the top surface 108 is formed by the face member F1. The body member B1 includes at least a part of the body portion bp1. In the present embodiment, the body member B1 includes a substantially entirety of the body portion bp1. The body member B1 includes at least a part of the hosel 110. In the present embodiment, the body member B1 includes the entirety of the hosel 110. The body member B1 may be integrally formed as a single-piece member, or may be formed by coupling a plurality of members.

As shown in FIG. 5 and FIG. 7, the body member B1 has an opening 120 that is open toward the face side. The opening 120 is covered by the face member F1. The body member B1 has an end surface 122 on the face side (hereinafter also referred to as a face-side end surface 122). The end surface 122 extends, around the opening 120, from the top side, through the toe side, to the sole side of the opening 120. The face member F1 is coupled to the end surface 122. This coupling is achieved by welding. The entirety of the end surface 122 lies on the same plane. The entirety of an abutment surface 124 of the face member F1 which is coupled to (abuts against) the end surface 122 also lies on the same plane. A boundary between the end surface 122 and the abutment surface 124 is a boundary 126 between the body member B1 and the face member F1.

As shown in FIG. 6, the body portion bp1 includes a weight receiving portion 130 on which the weight member W1 is disposed. The weight receiving portion 130 is provided in the body member B1. In the present embodiment, the weight receiving portion 130 constitutes a recess 132. The weight member W1 is disposed on the weight receiving portion 130. The weight member W1 is housed in the weight receiving portion 130 which is the recess 132. The weight member W1 is coupled to the weight receiving portion 130. The configuration (shape) of the weight receiving portion 130 is not limited to the recess 132.

The weight receiving portion 130 faces the hollow interior 116 (an empty space SP described later). The recess 132 is open toward the hollow interior 116 (empty space SP). The weight receiving portion 130 (recess 132) is covered by the face portion fp1 (face member F1) from the face side. The weight receiving portion 130 (recess 132) is not exposed outside the head 100. The weight member W1 disposed in the weight receiving portion 130 is not exposed outside the head 100. The weight member W1 is not viewable in the external appearance of the head 100. The weight receiving portion 130 is not viewable in the external appearance of the head 100.

As shown in FIG. 2, the weight member W1 has a toe-heel directional length D1. As shown in FIG. 6, the weight member W1 has a top-sole directional length D2. As shown in FIG. 6, the weight member W1 has a face-back directional length D3. The toe-heel directional length D1 is greater than the top-sole directional length D2. The toe-heel directional length D1 is greater than the face-back directional length D3.

As shown in FIG. 6, the entirety of the weight member W1 is located on the sole side relative to the head center of gravity G1. The entirety of the weight member W1 is located on the sole side relative to the face center Fc.

As shown in FIG. 2, the weight member W1 has a toe-side end Et and a heel-side end Eh. The weight member W1 extends continuously from the toe-side end Et to the heel-side end Eh. The toe-side end Et is located on the toe side relative to the face center Fc. The heel-side end Eh is located on the heel side relative to the face center Fc. As can be seen from FIG. 1 and FIG. 2, the toe-side end Et is located on the toe side relative to the toe middle position Pt1. The toe-side end Et is located on the toe side relative to the toe reference position Pt. The heel-side end Eh is located on the heel side relative to the heel middle position Ph1. The heel-side end Eh is located on the heel side relative to the heel reference position Ph. As shown in FIG. 2, when the head 100 is viewed from the front of the striking face 102, the weight member W1 extends from the toe side of the face center Fc, through the lower side of the face center Fc, to the heel side of the face center Fc.

The recess 132 is open toward the face side. An internal space formed by the recess 132 is continuous with the hollow interior 116. Only the hollow interior 116 is present between the weight member W1 and the face back surface 103, except for a coupling member to be described later. The recess 132 has a depth in the face-back direction. The weight member W1 is inserted into the recess 132 from the face side. When the weight receiving portion 130 is the recess 132, the orientation of the recess 132 is not limited. For example, the recess 132 may be open toward the top side.

The body portion bp1 includes a sole thin-wall portion 136. The sole thin-wall portion 136 constitutes a wall portion having the sole surface 104 as its outer surface. The sole thin-wall portion 136 extends toward the face side from a position located on the sole side of the weight member W1. The sole thin-wall portion 136 extends to a position on the face side relative to the weight member W1. The sole thin-wall portion 136 extends to reach the face back surface 103. The sole thin-wall portion 136 has a wall thickness t1. The wall thickness t1 of the sole thin-wall portion 136 is greater than or equal to 0.8 mm and less than or equal to 4.6 mm. The wall thickness t1 is measured in the top-sole direction.

The wall thickness t1 may vary in the above range of from 0.8 mm to 4.6 mm. The wall thickness t1 may be constant. The wall thickness t1 may be substantially constant. In this case, the ratio (t1max/t1min) of the maximum value t1max of the wall thickness t1 to the minimum value t1min of the wall thickness t1 may be set to be greater than or equal to 1.0 and less than or equal to 1.3, further set to be greater than or equal to 1.0 and less than or equal to 1.2, and still further set to be greater than or equal to 1.0 and less than or equal to 1.1.

In the present embodiment, the body member B1 includes the entirety of the sole thin-wall portion 136. A face-side end of the sole thin-wall portion 136 is the face-side end surface 122 of the body member B1. Alternatively, the face member F1 may include the entirety of the sole thin-wall portion 136. For example, in a face member F1 that is referred to as the above-described cup face, the sole-side extending portion can constitute the sole thin-wall portion 136. Further alternatively, the sole thin-wall portion 136 may be constituted by a part of the body member B1 and a part of the face member F1. For example, a face-side part of the sole thin-wall portion 136 may be constituted by the sole-side extending portion of the face member F1, and a back-side part of the sole thin-wall portion 136 may be constituted by a part of the body member B1. In this case, the boundary between the face member F1 and the body member B1 can be located in the sole thin-wall portion 136. When the boundary between the face member F1 and the body member B1 is located in the sole thin-wall portion 136 and the coupling member (weld bead or the like) is disposed at the boundary, the coupling member increases the wall thickness t1. From this viewpoint, it is preferable that the boundary between members is not located in the sole thin-wall portion 136. In other words, the entirety of the sole thin-wall portion 136 is preferably included in an integrally-formed single-piece member.

FIG. 6 is a vertical cross section passing through the face center Fc. The head 100 includes the sole thin-wall portion 136 in the vertical cross section passing through the face center Fc. Further, the sole thin-wall portion 136 has a length in the toe-heel direction. The sole thin-wall portion 136 is formed in a region extending from the toe middle position Pt1 to the heel middle position Ph1. The sole thin-wall portion 136 is formed in a region extending from the toe reference position Pt to the heel reference position Ph. The scope of presence of the sole thin-wall portion 136 in the toe-heel direction is equal to the scope of presence of the weight receiving portion 130 in the toe-heel direction. The sole thin-wall portion 136 is formed on the sole side of the weight receiving portion 130 (recess 132) along the weight receiving portion 130 (recess 132).

FIG. 8 shows the same cross-sectional view as FIG. 6. FIG. 8 also includes a coupling member 138 that is not shown in FIG. 6. Examples of the coupling member 138 include the following (a) to (c).

- (a) A material added to couple the weight member W1 to the weight receiving portion 130
- (b) A melted material including a melted part of the body portion bp1 and/or a melted part of the weight member W1
- (c) A combination of the material (a) and the melted material (b)

Examples of the above material (a) include a filler material, a brazing material, a soldering material, and an adhesive.

In the embodiment of FIG. 8, the coupling member 138 is present at a position at which an interface between the weight member W1 and the weight receiving portion 130 is not located. The coupling member 138 may be present or may be absent at the position at which the interface between the weight member W1 and the weight receiving portion 130 is not located. For example, the coupling member 138 may be present only at the interface between the weight member W1 and the weight receiving portion 130. In this case, the cross-sectional view of the head 100 is as shown in FIG. 6. Although FIG. 6 is a cross-sectional view in which the coupling member 138 is omitted from the present embodiment, FIG. 6 also shows a cross-sectional view of a modification example of the present embodiment in which the coupling member 138 is not present on the face side of the weight member W1.

In the embodiment of FIG. 8, a part of the recess 132 which is not filled with the weight member W1 is filled with the coupling member 138. The coupling member 138 is present on the face side of the weight member W1. The coupling member 138 also permeates into the interface between the weight member W1 and the weight receiving portion 130.

The coupling member 138 includes a face-side portion 138a located on the face side of the weight member W1. The face-side portion 138a is located inside the recess 132. The face-side portion 138a can contribute to increase in fixing strength of the weight member W1 to the recess 132.

The method for coupling the weight member W1 to the weight receiving portion 130 is not limited. Examples of the method include welding and adhesion using an adhesive. Examples of the welding include fusion welding, pressure welding, brazing and soldering. When “welding” in a narrow sense in which base materials (the weight member W1 and the body portion bp1) are melted is used as the coupling method, the coupling member 138 can be a weld bead and/or a filler material. In the present embodiment, brazing is used as the coupling method. That is, the coupling member 138 is made of a brazing material. Examples of the brazing material include silver brazing alloys, copper brazing alloys, and copper-phosphorus brazing alloys. In the present embodiment, a silver brazing alloy is used.

The outer surface 136a of the sole thin-wall portion 136 constitutes a part of the sole surface 104. The inner surface 136b of the sole thin-wall portion 136 includes: a weight contact surface 140 that constitutes a part of the weight receiving portion 130 (recess 132) and is in contact with the weight member W1; and a space facing surface 142 that faces the empty space SP. The empty space SP onto which the space facing surface 142 faces is the hollow interior 116. The space facing surface 142 constitutes a side surface on the sole side of the recess 132. When the head 100 is a cavity back iron head, the empty space SP can be a space in its back cavity.

The sole thin-wall portion 136 extends continuously from a position located on the sole side of the weight member W1 to the face portion fp1. The inner surface 136b of the sole thin-wall portion 136 extends continuously from the weight contact surface 140 to the space facing surface 142. A face-side end of the space facing surface 142 is located on the face back surface 103. A face-side end of the inner surface 136b of the sole thin-wall portion 136 is located on the face back surface 103.

The sole thin-wall portion 136 includes a front part 144 whose inner surface is the space facing surface 142, and a rear part 146 whose inner surface is the weight contact surface 140. The front part 144 is located on the face side relative to the rear part 146. A portion sandwiched between the front part 144 and the rear part 146 is also a part of the sole thin-wall portion 136. The sole thin-wall portion 136 extends continuously from the front part 144 to the rear part 146.

The inner surface 136b of the sole thin-wall portion 136 includes a coupling-member contact surface 143 that is in contact with the face-side portion 138a of the coupling member 138. The coupling-member contact surface 143 is located between the weight contact surface 140 and the space facing surface 142. The weight contact surface 140 is contiguous with the back side of the coupling-member contact surface 143, and the space facing surface 142 is contiguous with the face side of the coupling-member contact surface 143. The sole thin-wall portion 136 includes an intermediate part 148 whose inner surface is the coupling-member contact surface 143. The coupling member 138 is made of a brazing material. The material of the coupling member 138 has a lower rigidity than the material of the weight member W1. This rigidity may be determined by the Young's modulus of the material. The coupling member 138 does not hinder deflection of the sole thin-wall portion 136 as much as the weight member W1 would. The face-side portion 138a can increase the fixing strength of the weight member W1 to the weight receiving portion 130 while suppressing its influence on the deflection of the sole thin-wall portion 136.

The body portion bp1 includes a top-side forming portion 150 located on the top side of the weight receiving portion 130. The top-side forming portion 150 faces the hollow interior 116. The top-side forming portion 150 includes a top-side contact surface 152 that constitutes a part of the weight receiving portion 130 (recess 132) and is in contact with the weight member W1. The top-side contact surface 152 constitutes a side surface on the top side of the recess 132. The top-side forming portion 150 includes a front surface 154. The front surface 154 constitutes an opposite surface that is opposite to the face back surface 103. The front surface 154 and the face back surface 103 are opposite to each other across the empty space SP. The empty space SP is the hollow interior 116. A sole-side edge 154a of the front surface 154 constitutes a part of an opening edge of the recess 132. In the present embodiment, the front surface 154 is parallel to the striking face 102. In the embodiment of FIG. 8, the wall thickness (wall thickness in the top-sole direction) of the top-side forming portion 150 is greater than the wall thickness t1 of the sole thin-wall portion 136.

The front surface 154 is not located on the face side relative to the boundary 126 between the body member B1 and the face member F1. The front surface 154 is located on the back side relative to the boundary 126 between the body member B1 and the face member F1.

FIG. 9 shows a head 200 according to a second embodiment as viewed from the front of its striking face 102. The head 200 is different from the head 100 of the first embodiment in the configuration (shape) of the weight receiving portion 130 (recess 132) and the configuration (shape) of the weight member W1. Except for this point, the head 200 is the same as the head 100.

With the weight member W1 of the head 200, more weight is allocated to a toe side portion of the head 200. The weight member W1 can be divided into a toe side portion W1t and a heel side portion W1h by the vertical cross section passing through the face center Fc. The weight of the toe side portion W1t is greater than the weight of the heel side portion W1h. The volume of the toe side portion W1t is greater than the volume of the heel side portion W1h. The length D1t of the toe side portion W1t is greater than the length D1h of the heel side portion W1h. The length D1t and the length D1h are measured in the toe-heel direction. A portion where the top-sole directional length D2 of the weight member W1 is maximum is located in the toe side portion W1t. The toe-side end Et of the weight member W1 is located on the toe side relative to the toe reference position Pt (see FIG. 1).

FIG. 10 shows a head 300 according to a third embodiment as viewed from the front of its striking face 102. The head 300 is different from the head 100 of the first embodiment in the configuration (shape) of the weight member W1. Except for this point, the head 300 is the same as the head 100.

The weight member W1 of the head 300 is divided and separately disposed in a toe-side part and a heel-side part of the head 300. The weight member W1 includes a toe weight member Wt and a heel weight member Wh separated from each other. The toe weight member Wt is located on the toe side relative to the heel weight member Wh. The entirety of the toe weight member Wt is located on the toe side relative to the face center Fc. The entirety of the heel weight member Wh is located on the heel side relative to the face center Fc. The weight receiving portion 130 (recess 132) extends from the toe-side part to the heel-side part of the head 300 as with the head 100. A gap in which the weight member W1 is absent is present between the toe weight member Wt and the heel weight member Wh in the weight receiving portion 130 (recess 132). This gap is referred to as a weight-member gap portion 133. The weight-member gap portion 133 is an empty space. A toe-heel directional area in which the weight-member gap portion 133 extends includes the face center Fc. The weight-member gap portion 133 eliminates the rear part 146, and the front part 144 which is easy to bend is enlarged to the back side (see FIG. 8). The presence of the weight-member gap portion 133 causes easy deflection of the sole thin-wall portion 136. The center of gravity of the toe weight member Wt may be located on the toe side relative to the toe middle position Pt1 (see FIG. 1). The center of gravity of the heel weight member Wh may be located on the heel side relative to the heel middle position Ph1 (see FIG. 1).

The toe weight member Wt has a toe-heel directional length Dt. The heel weight member Wh has a toe-heel directional length Dh. When the weight member W1 is separated into a plurality of parts, the toe-heel directional length D1 of the weight member W1 is the sum of the toe-heel directional lengths of the parts. In the present embodiment, the length D1 is the sum of the length Dt and the length Dh.

When the weight member W1 is separated into the toe weight member Wt and the heel weight member Wh, the lateral MOI of the head 300 can be increased. In addition, this structure allows the designer to change the ratio of the weight of the toe weight member Wt to the weight of the heel weight member Wh, whereby the position of the head center of gravity G1 can be easily adjusted.

The specific gravity of the weight member W1 is greater than the specific gravity of the body portion bp1. The specific gravity of the weight member W1 is greater than the specific gravity of the face portion fp1. The specific gravity of the weight member W1 is greater than the specific gravity of the body member B1. The specific gravity of the weight member W1 is greater than the specific gravity of the face member F1. In comparison between specific gravities, when a member and/or a portion is made of a plurality of materials, its average specific gravity is considered as its specific gravity. The average specific gravity is calculated by dividing the total weight (g) by the total volume (cm³).

The body member B1 may be made of a metal, for example. Examples of the metal include stainless steel, soft iron, maraging steel, and a titanium alloy. The body member B1 may be made of a material other than a metal, for example, a carbon fiber reinforced resin. The body member B1 may be made of a plurality of materials.

The face member F1 may be made of a metal, for example. Examples of the metal include a titanium alloy, stainless steel, chrome vanadium steel, and maraging steel. The face member F1 may be made of a material other than a metal, for example, a carbon fiber reinforced resin. The face member F1 may be made of a plurality of materials.

The weight member W1 may be made of a metal, for example. Examples of the metal include an alloy containing tungsten and/or nickel. From the viewpoint of having a high specific gravity, an alloy containing tungsten and nickel is more preferable.

From the viewpoint of lowering the position of the head center of gravity, the specific gravity of the weight member W1 is preferably greater than or equal to 9, more preferably greater than or equal to 10, and still more preferably greater than or equal to 11. Considering availability of the material, the specific gravity of the weight member W1 is preferably less than or equal to 20, more preferably less than or equal to 19, and still more preferably less than or equal to 18.

Considering a material having a sufficient strength for the body portion bp1, the specific gravity of the body portion bp1 is preferably greater than or equal to 4.0, more preferably greater than or equal to 4.1, and still more preferably greater than or equal to 4.2. From the viewpoint of lowering the position of the head center of gravity, the difference between the specific gravity of the body portion bp1 and the specific gravity of the weight member W1 is preferably great. From this viewpoint, the specific gravity of the body portion bp1 is preferably less than or equal to 8.0, more preferably less than or equal to 7.95, and still more preferably less than or equal to 7.9. Considering a material having a sufficient strength for the face portion fp1, the specific gravity of the face portion fp1 is preferably greater than or equal to 4.0, more preferably greater than or equal to 4.1, and still more preferably greater than or equal to 4.2. From the viewpoint of lowering the position of the head center of gravity, the difference between the specific gravity of the face portion fp1 and the specific gravity of the weight member W1 is preferably great. From this viewpoint, the specific gravity of the face portion fp1 is preferably less than or equal to 8.0, more preferably less than or equal to 7.95, and still more preferably less than or equal to 7.9.

Considering a material having a sufficient strength for the body member B1, the specific gravity of the body member B1 is preferably greater than or equal to 4.0, more preferably greater than or equal to 4.1, and still more preferably greater than or equal to 4.2. From the viewpoint of lowering the position of the head center of gravity, the difference between the specific gravity of the body member B1 and the specific gravity of the weight member W1 is preferably great. From this viewpoint, the specific gravity of the body member B1 is preferably less than or equal to 8.0, more preferably less than or equal to 7.95, and still more preferably less than or equal to 7.9. Considering a material having a sufficient strength for the face member F1, the specific gravity of the face member F1 is preferably greater than or equal to 4.0, more preferably greater than or equal to 4.1, and still more preferably greater than or equal to 4.2. From the viewpoint of lowering the position of the head center of gravity, the difference between the specific gravity of the face member F1 and the specific gravity of the weight member W1 is preferably great. From this viewpoint, the specific gravity of the face member F1 is preferably less than or equal to 8.0, more preferably less than or equal to 7.95, and still more preferably less than or equal to 7.9.

The above-shown embodiments exhibit the following advantageous effects.

The weight member W1 in which the toe-heel directional length D1 is greater than the top-sole directional length D2 is disposed so as to be in contact with the sole thin-wall portion 136. This structure can lower the position of the center of gravity of the head. The head having a lower center of gravity can make the launch angle of a hit ball higher.

The sole thin-wall portion 136 allows the lower part of the face portion fp1 to bend more easily, which can improve the rebound performance of the head in hitting at a lower hit point.

The sole thin-wall portion 136 includes the front part 144 having the space facing surface 142. This front part 144 is easy to bend and can enhance the rebound performance of the head in hitting at a lower hit point.

The sole thin-wall portion 136 extends continuously from a position located on the sole side of the weight member W1 to the face portion fp1. Accordingly, the sole thin-wall portion 136 effectively bends at impact between a golf ball and the face portion fp1, which can enhance the rebound performance of the head in hitting at a lower hit point.

The weight member W1 is not exposed outside the head, which can improve the appearance of the head. The weight member W1 is not exposed outside the head, which enables a design in which a joint portion between the weight member W1 and the weight receiving portion 130 is not exposed to the outside. This can enhance flexibility of appearance design of the joint portion, and enables easier production of the head.

A double-pointed arrow D1 in FIG. 2 shows the toe-heel directional length of the weight member W1. A double-pointed arrow D2 in FIG. 6 shows the top-sole directional length of the weight member W1. A double-pointed arrow D3 in FIG. 6 shows the face-back directional length of the weight member W1. The unit of the lengths D1, D2, and D3 is mm. As described above, the toe-heel directional length D1 is greater than the top-sole directional length D2. In the above embodiments, the top-sole directional length D2 is greater than the face-back directional length D3.

From the viewpoint of lowering the position of the head center of gravity, the top-sole directional length D2 is preferably less than or equal to 20 mm, more preferably less than or equal to 15 mm, still more preferably less than or equal to 10 mm, and yet more preferably less than or equal to 7 mm. From the viewpoint of increasing the weight of the weight member W1, the top-sole directional length D2 is preferably greater than or equal to 3.0 mm, more preferably greater than or equal to 3.5 mm, and still more preferably greater than or equal to 4.0 mm.

From the viewpoint of increasing the weight of the weight member W1 and increasing a depth D4 of the head center of gravity, the face-back directional length D3 is preferably greater than or equal to 3.0 mm, more preferably greater than or equal to 3.3 mm, and still more preferably greater than or equal to 3.6 mm. From the viewpoint of a restriction on the head dimensions and from the viewpoint of reducing a height H2 of the sweet spot SS (hereinafter also referred to as sweet spot height H2), the face-back directional length D3 is preferably less than or equal to 18 mm, more preferably less than or equal to 16 mm, and still more preferably less than or equal to 14 mm.

A double-pointed arrow H1 in FIG. 1 shows a head height. The head height H1 is measured at the toe-heel directional position of the face center Fc. The top-sole directional height of a head at the face center is the head height H1. The head height H1 is measured in the top-sole direction. The unit of the head height H1 is mm.

A ratio D2/H1 of the top-sole directional length D2 of the weight member W1 to the head height H1 may be considered. From the viewpoint of lowering the position of the head center of gravity, D2/H1 is preferably less than or equal to 0.5, more preferably less than or equal to 0.4, still more preferably less than or equal to 0.3, and yet more preferably less than or equal to 0.2. From the viewpoint of increasing the weight of the weight member W1, D2/H1 is preferably greater than or equal to 0.05, more preferably greater than or equal to 0.06, and still more preferably greater than or equal to 0.07.

A double-pointed arrow H2 in FIG. 6 shows the sweet spot height. The sweet spot height H2 is the height of the sweet spot SS measured from the ground plane HP when the head is in the reference state. The sweet spot height H2 is measured in a direction perpendicular to the ground plane HP. The unit of the sweet spot height H2 is mm.

A ratio H2/H1 of the sweet spot height H2 to the head height H1 may be considered. From the viewpoint of lowering the position of the head center of gravity, H2/H1 is preferably less than or equal to 0.50, more preferably less than or equal to 0.48, and still more preferably less than or equal to 0.46. Considering a required head shape, there is a limit in the lowering of the position of the head center of gravity. H2/H1 may be set to be greater than or equal to 0.30, further set to be greater than or equal to 0.31, and still further set to be greater than or equal to 0.32.

A double-pointed arrow D4 in FIG. 6 shows the depth of the head center of gravity. The depth D4 of the head center of gravity means a distance between the striking face 102 and the head center of gravity G1. The depth D4 of the head center of gravity is measured in the face-back direction. The unit of the depth D4 of the head center of gravity is mm.

A double-pointed arrow D5 in FIG. 8 shows a head thickness. The head thickness D5 is measured at the toe-heel directional position of the face center Fc. The head thickness D5 is measured in the face-back direction. The unit of the head thickness D5 is mm.

A ratio D4/D5 of the depth D4 of the head center of gravity to the head thickness D5 may be considered. From the viewpoint of reducing the sweet spot height H2, D4/D5 is preferably less than or equal to 0.50, more preferably less than or equal to 0.40, and still more preferably less than or equal to 0.35. An excessively small depth D4 of the head center of gravity tends to reduce the moment of inertia of the head. From this viewpoint, D4/D5 is preferably greater than or equal to 0.10, more preferably greater than or equal to 0.15, and still more preferably greater than or equal to 0.20.

A double-pointed arrow D6 in FIG. 6 shows a distance between the front surface 154 of the top-side forming portion 150 and the face back surface 103. This distance is measured in the face-back direction. From the viewpoint of reducing the sweet spot height H2, the distance D6 is preferably less than or equal to 7.0 mm, more preferably less than or equal to 6.5 mm, and still more preferably less than or equal to 6.0 mm. From the viewpoint of increasing the depth D4 of the head center of gravity and increasing the moment of inertia of the head, the distance D6 is preferably greater than or equal to 0.8 mm, more preferably greater than or equal to 1.0 mm, and still more preferably greater than or equal to 1.2 mm.

From the viewpoint of suppressing the depth D4 of the head center of gravity and reducing the sweet spot height H2, the top-sole directional length D2 of the weight member W1 is preferably greater than the face-back directional length D3 of the weight member W1. From this viewpoint, D2/D3 is preferably greater than or equal to 1.05, more preferably greater than or equal to 1.10, and still more preferably greater than or equal to 1.15. An excessively great top-sole directional length D2 makes the position of the center of gravity of the weight member W1 higher. From this viewpoint, D2/D3 is preferably less than or equal to 7.0, more preferably less than or equal to 6.0, and still more preferably less than or equal to 5.0.

When the volume of the weight member W1 is denoted by V1 (cm³) and the volume of the head is denoted by V2 (cm³), a ratio V1/V2 may be considered. When the weight member W1 has a sufficient weight, the effect of shifting of the position of the head center of gravity brought by the weight member W1 can be enhanced. From this viewpoint, V1/V2 is preferably greater than or equal to 0.010, more preferably greater than or equal to 0.015, and still more preferably greater than or equal to 0.020. By locally disposing the weight member W1, the effect of shifting of the position of the head center of gravity brought by the weight member W1 can be enhanced. From this viewpoint, V1/V2 is preferably less than or equal to 0.1, more preferably less than or equal to 0.09, and still more preferably less than or equal to 0.08.

A ratio Rt of the weight of a part of the weight member W1 located on the toe side relative to the head center of gravity G1 to the weight of the entirety of the weight member W1 may be greater than or equal to 60%. With the weight of the hosel 110 and the weight of the toe side portion of the head increased by the weight member W1, the head weight is distributed towards peripheral portions in the toe-heel direction. This can increase the lateral MOI of the head. The increased lateral MOI can enlarge the sweet area of the head, which can enhance the forgiveness of the head. From this viewpoint, the ratio Rt may be greater than or equal to 65%, and further may be greater than or equal to 70%. From the viewpoint of having a sufficient toe-heel directional length D1, the ratio Rt may be less than or equal to 908, further may be less than or equal to 85%, and still further may be less than or equal to 80%. When a head is in the reference state, an axis that passes through the head center of gravity G1 and is perpendicular to the ground plane HP is determined. The moment of inertia of the head about this axis is the lateral MOI.

From the viewpoint of increasing the weight of the weight member W1 while lowering the position of the center of gravity of the weight member W1, the toe-heel directional length D1 is preferably greater than or equal to 10 mm, more preferably greater than or equal to 20 mm, and still more preferably greater than or equal to 30 mm. From the viewpoint of a restriction on the head dimensions, the toe-heel directional length D1 is preferably less than or equal to 66 mm, more preferably less than or equal to 65 mm, and still more preferably less than or equal to 64 mm.

From the viewpoint of reducing the sweet spot height H2, the depth D4 of the head center of gravity is preferably less than or equal to 10 mm, more preferably less than or equal to 9 mm, still more preferably less than or equal to 8 mm, and yet more preferably less than or equal to 7 mm. From the viewpoint of increasing the moment of inertia of the head, the depth D4 of the head center of gravity is preferably greater than or equal to 3 mm, more preferably greater than or equal to 3.5 mm, and still more preferably greater than or equal to 4 mm.

A projected area of the weight member W1 is obtained by projecting the weight member W1 onto the striking face 102. The direction of the projection is perpendicular to the striking face 102. This projected area is denoted by S1 (mm²). The area of the striking face 102 is denoted by S2 (mm²). The area of the striking face 102 is measured in a state where the score lines gv are filled to be a smooth striking face. In the iron type heads of the above embodiments, the contour line of the striking face 102 is determined as the boundary line between a flat part and a non-flat part, and the area of the figure drawn by the contour line is considered as the area S2 of the striking face 102. The area S2 is also referred to as a face area.

A ratio S1/S2 of the projected area S1 of the weight member W1 to the face area S2 can be considered. When the weight member W1 has a sufficient weight, the effect of shifting of the position of the head center of gravity brought by the weight member W1 can be enhanced. From this viewpoint, S1/S2 is preferably greater than or equal to 0.03, more preferably greater than or equal to 0.04, still more preferably greater than or equal to 0.05, and yet more preferably greater than or equal to 0.06. By locally disposing the weight member W1, the effect of shifting of the position of the head center of gravity brought by the weight member W1 can be enhanced. From this viewpoint, S1/S2 is preferably less than or equal to 0.17, more preferably less than or equal to 0.15, and still more preferably less than or equal to 0.13.

A double-pointed arrow D7 in FIG. 8 shows the depth of the recess 132 constituting the weight receiving portion 130. The depth D7 is measured in the face-back direction. In the measurement of the depth D7, a deepest point Pd that is the starting point for measuring the depth D7 is a point where the weight member W1 is most deeply inserted into the recess 132.

From the viewpoint of easy fixing of the weight member W1, the depth D7 is preferably greater than or equal to 3 mm, more preferably greater than or equal to 3.5 mm, and still more preferably greater than or equal to 4 mm. Considering the preferable value of the face-back directional length D3 of the weight member W1, the depth D7 of the recess 132 is preferably less than or equal to 18 mm, more preferably less than or equal to 17 mm, and still more preferably less than or equal to 16 mm.

A double-pointed arrow D8 in FIG. 8 shows the distance between the back-side end of the weight member W1 and the striking face 102. The distance D8 is measured in the face-back direction. The distance D8 may be the maximum value of distances D8 that can be measured in cross sections taken at all different positions in the toe-heel direction. A ratio D8/D5 of the distance D8 to the head thickness D5 may be considered. From the viewpoint of reducing the sweet spot height H2, D8/D5 may be less than or equal to 0.50, further may be less than or equal to 0.48, and still further may be less than or equal to 0.46. However, from the viewpoint of increasing the lateral MOI, D8/D5 may be greater than 0.50. Considering the face-back directional length D3 of the weight member W1, the wall thickness of the face portion fp1, and the like, D8/D5 may be greater than or equal to 0.30, further may be greater than or equal to 0.33, and still further may be greater than or equal to 0.36.

As described above, the wall thickness t1 of the sole thin-wall portion 136 is greater than or equal to 0.8 mm and less than or equal to 4.6 mm. A smaller wall thickness t1 can lower the position of the weight member W1, which can lower the position of the head center of gravity. A smaller wall thickness t1 can also reduce the rigidity of the sole thin-wall portion 136, which can improve the rebound performance of the head in hitting at a lower hit point. From this viewpoint, the wall thickness t1 of the sole thin-wall portion 136 is preferably less than or equal to 4.6 mm, more preferably less than or equal to 3.0 mm, and still more preferably less than or equal to 2.0 mm. From the viewpoint of durability of the head, the wall thickness t1 of the sole thin-wall portion 136 is preferably greater than or equal to 0.8 mm, more preferably greater than or equal to 0.9 mm, and still more preferably greater than or equal to 1.0 mm.

A head having many opportunities to hit balls placed directly on the ground, not being teed up, has a great advantage in improvement of the rebound performance of the head in hitting at a lower hit point. From this viewpoint, the head of the present disclosure is preferably a hybrid type head (excluding an iron type hybrid head) or an iron type head (including an iron type hybrid head), and more preferably an iron type head. In a club having a relatively small loft angle, a hit ball tends to have a lower flight trajectory. Accordingly, such a club has a great advantage when its head has a lower center of gravity to hit a ball with a high flight trajectory. From this viewpoint, the real loft angle of the head is preferably less than or equal to 38°, more preferably less than or equal to 35°, and still more preferably less than or equal to 33°. Considering the lower limit value of the loft angle of the iron type head, the real loft angle of the head is preferably greater than or equal to 15°, more preferably greater than or equal to 17°, still more preferably greater than or equal to 19°, and yet more preferably greater than or equal to 21°.

The method for producing the head is not limited. In the heads of the above-described embodiments, the face member F1 is coupled to the body member B1, and the body member B1 includes the weight receiving portion 130. Such a head can be produced, for example, by a production method including the following steps (1) to (3) of:

- (1) preparing a face member F1, a body member B1, and a weight member W1;
- (2) coupling the weight member W1 to the weight receiving portion 130 of the body member B1; and
- (3) coupling the face member F1 to the body member B1 to which the weight member W1 is coupled.

EXAMPLES
Example

A head having the same configuration as the head 100 of the first embodiment was produced. The body member B1 was produced by casting (lost-wax precision casting). The body member B1 was made of stainless steel. The face member F1 was produced by forging. The face member F1 was made of maraging steel. The weight member W1 was produced by powder sintering. The weight member W1 was made of an alloy containing tungsten and nickel. The weight member W1 was housed in the recess 132 of the weight receiving portion 130 and was coupled to the recess 132 by brazing. As to the weight member W1, its specific gravity was 12, its weight was 10 g, its toe-heel directional length D1 was 56.5 mm, its top-sole directional length D2 was 4.6 mm, and its face-back directional length D3 was 4.0 mm. Of the head of Example, a part other than the weight member W1 had a specific gravity (average specific gravity) of 7.83. The head was produced by the above-described steps (1) to (3).

A head having a real loft angle of 28.5° (7-iron) was produced. In this head (7-iron), the sweet spot height H2 was 19.6 mm, the head height H1 was 45.8 mm, the depth D4 of the head center of gravity was 5.8 mm, and the head thickness D5 was 20.5 mm. A head having a real loft angle of 25.5° (6-iron) was produced. In this head (6-iron), the sweet spot height H2 was 19.4 mm, the head height H1 was 45.1 mm, the depth D4 of the head center of gravity was 6.4 mm, and the head thickness D5 was 20.8 mm. A head having a real loft angle of 23.0° (5-iron) was produced. In this head (5-iron), the sweet spot height H2 was 19.1 mm, the head height H1 was 44.6 mm, the depth D4 of the head center of gravity was 6.4 mm, and the head thickness D5 was 20.7 mm. A head having a real loft angle of 21.0° (4-iron) was produced. In this head (4-iron), the sweet spot height H2 was 19.3 mm, the head height H1 was 44.0 mm, the depth D4 of the head center of gravity was 6.4 mm, and the head thickness D5 was 21.0 mm. In all of the heads, D2/H1, H2/H1, D4/D5 and the like fell within their respective preferable ranges, and the position of the head center of gravity was lowered. The projected area S1 of the weight member W1 was 252 mm³, and the face area S2 was 3009 mm³(7-iron).

Comparative Example

For observing rebound performance of each head in hitting at a lower hit point, a head of Comparative Example was produced. FIG. 11 shows a head 400 of Comparative Example as viewed from the front of its striking face 102. In the head 400, the weight receiving portion 130 (recess 132) was provided only in a toe-side part, and the weight member W1 was also disposed only in the toe-side part. The sole thin-wall portion 136 was not formed in a part where the recess 132 was absent. The weight member W1 had a specific gravity of 12, and had a weight of 10 g. The head 400 (7-iron) of Comparative Example was obtained in the same manner as in the head of Example except for the position of the weight receiving portion 130 and the position of the weight member W1.

The heads of Example and Comparative Example were subjected to measurement of COR at a lower hit point. In this measurement of each head, a first point was set on the striking face 102. In each head which was in the reference state, a point having a height (height in the vertical direction) from the ground plane HP of 15 mm, and located at the same toe-heel directional position as the face center Fc was defined as the first point. The first point was close to the ground plane HP and was located on the lower side (sole side) relative to the face center Fc. Further, a point that was spaced 5 mm apart from the first point toward the sole side in the top-sole direction was defined as a second point. Further, additional measurement points were set at intervals of 5 mm in the toe-heel direction and at intervals of 5 mm in the top-sole direction, from the first point. The COR of each head was measured at all the measurement points including the first point and the second point. The maximum COR value of the measured COR values for each head was obtained by comparing the measured COR values at all the measurement points.

In the head of Example, the ratio of the COR at the first point to the maximum COR value was 96%, and the ratio of the COR at the second point to the maximum COR value was 86%. In the head of Comparative Example, the ratio of the COR at the first point to the maximum COR value was 938, and the ratio of the COR at the second point to the maximum COR value was 83%. The head of Example was superior in rebound performance in hitting at a lower hit point to the head of Comparative Example.

The COR means a coefficient of restitution. The COR was measured according to “Interim Procedure for Measuring the Coefficient of Restitution of an Iron Clubhead Relative to a Baseline Plate Revision 1.3 Jan. 1, 2006” specified by the USGA (United States Golf Association).

The following clauses are a part of invention included in the present disclosure.

[Clause 1]

A golf club head including: a striking face, and a sole surface, wherein

- the golf club head includes a face portion including the striking face, a body portion, and a weight member disposed in the body portion,
- the body portion includes a weight receiving portion on which the weight member is disposed,
- the weight member is coupled to the weight receiving portion,
- a toe-heel directional length of the weight member is greater than a top-sole directional length of the weight member,
- the body portion includes a sole thin-wall portion whose outer surface constitutes a part of the sole surface and that has a wall thickness of greater than or equal to 0.8 mm and less than or equal to 4.6 mm,
- an inner surface of the sole thin-wall portion includes: a weight contact surface that constitutes a part of the weight receiving portion and is in contact with the weight member; and a space facing surface that is located on a face side of the weight contact surface and faces an empty space, and
- the weight member is not exposed outside the golf club head.

[Clause 2]

The golf club head according to clause 1, wherein the sole thin-wall portion extends continuously from a position located on a sole side of the weight member to the face portion.

[Clause 3]

The golf club head according to clause 1 or 2, wherein an entirety of the sole thin-wall portion is included in an integrally-formed single-piece member.

[Clause 4]

The golf club head according to any one of clauses 1 to 3, wherein

when the top-sole directional length of the weight member is denoted by D2, and a top-sole directional height of the golf club head at a position of a face center is denoted by H1, then D2/H1 is greater than or equal to 0.05 and less than or equal to 0.5.

[Clause 5]

The golf club head according to any one of clauses 1 to 4, wherein

when a sweet spot height is denoted by H2, and a top-sole directional height of the golf club head at a position of a face center is denoted by H1, then H2/H1 is greater than or equal to 0.30 and less than or equal to 0.50.

[Clause 6]

The golf club head according to any one of clauses 1 to 5, wherein

when a depth of a center of gravity of the golf club head is denoted by D4, and a face-back directional thickness of the golf club head at a position of a face center is denoted by D5, then D4/D5 is greater than or equal to 0.10 and less than or equal to 0.50.

[Clause 7]

The golf club head according to any one of clauses 1 to 6, wherein

when a projected area of the weight member obtained by projecting the weight member onto the striking face is denoted by S1, and an area of the striking face is denoted by S2, then S1/S2 is greater than or equal to 0.03 and less than or equal to 0.17.

LIST OF REFERENCE SYMBOLS

- 100, 200, 300, 400 Golf club head
- 102 Striking face
- 103 Face back surface
- 104 Sole surface
- 106 Back surface
- 108 Top surface
- 110 Hosel
- 116 Hollow interior
- 120 Opening of the body member
- 130 Weight receiving portion
- 132 Recess
- 136 Sole thin-wall portion
- 136
  a Outer surface of the sole thin-wall portion
- 136
  b Inner surface of the sole thin-wall portion
- 138 Coupling member
- 140 Weight contact surface
- 142 Space facing surface
- 150 Top-side forming portion
- 154 Front surface of the top-side forming portion
- Fc Face center
- SP Empty space (Hollow interior)
- gv Score lines
- gv1 Longest score line
- F1 Face member
- B1 Body member
- W1 Weight member
- Pt Toe reference position
- Pc Score line center position
- Ph Heel reference position
- Le Leading edge
- Te Trailing edge

The above descriptions are merely illustrative and various modifications can be made without departing from the principles of the present disclosure.

The terminology used in the description of the various described embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. The use of the terms “a”, “an”, “the”, and similar referents in the context of throughout this disclosure (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. As used throughout this disclosure, the word “may” is used in a permissive sense (i.e., meaning “having the potential to”), rather than the mandatory sense (i.e., meaning “must”). Similarly, as used throughout this disclosure, the terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted.

GOLF CLUB HEAD

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Priority Claims (1)