Golf club head

Abstract

To provide an iron type golf club head including a sole that exhibits excellent performance based on a novel shape.SOLUTION: An iron type golf club head 100 includes a hitting face 102 including a plurality of score lines gv, a sole surface 104a, a leading edge Le that constitutes a front edge of the sole surface 104a, a trailing edge Te that constitutes a rear edge of the sole surface 104a, and a score line center position c1 that is determined based on the score lines gv. The sole surface 104a includes a ridge line 120 that extends from a toe side to a heel side and an additional surface 122 to cross the ridge line 120. The additional surface 122 is a flat surface or a recessed surface. The additional surface 122 may include a heel part 122h that is located on a heel side with respect to the score line center position c1, and a toe part 122t that is located on a toe side with respect to the score line center position c1.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a golf club head.

Background Art

[0002] An iron-type golf club head characterized by the shape of the sole has been proposed. The golf club head disclosed in Japanese Patent Application Laid-Open No. 2015-186514 has a face with a score line formed thereon and a sole with a recess formed therein. This recess is formed only on the toe side of the center in the length direction of the score line. Alternatively, this recess is formed such that the length on the toe side of the center in the length direction is longer than the length on the heel side. In this head, head rotation in the direction in which the face closes is unlikely to occur.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor has found that a novel sole shape can stabilize contact with the ball, have good release performance, and further produce another effect. An object of the present invention is to provide an iron-type golf club head having a high-performance sole based on a novel shape.

Means for Solving the Problems

[0005] In one aspect, an iron-type golf club head includes a striking face having a plurality of score lines, a sole surface, and a leading edge that forms the leading edge of the sole surface. DeThe sole has a wing edge and a trailing edge that forms the rear edge of the sole surface. The sole surface has a ridge line extending from the toe side to the heel side and an additional surface that is a flat or concave surface formed to straddle the ridge line. [Effects of the Invention]

[0006] One aspect of this is the provision of iron-type golf club heads equipped with a high-performance sole that produces multiple effects through its novel shape. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a front view of a golf club head according to the first embodiment. [Figure 2] Figure 2 is a bottom view of the golf club head shown in Figure 1. [Figure 3] Figure 3 is a cross-sectional view along line AA in Figure 2. [Figure 4] Figure 4 is a cross-sectional view along line BB in Figure 2. [Figure 5] Figure 5(a) is an enlarged view of the area within the rectangle in Figure 4, and Figure 5(b) is a partial enlarged view of the cross section along the CC line in Figure 2. [Figure 6] Figure 6 is a front view of the golf club head according to the second embodiment. [Figure 7] Figure 7 is a bottom view of the golf club head shown in Figure 6. [Figure 8] Figure 8 is a cross-sectional view along line AA in Figure 7. [Figure 9] Figure 9 is a cross-sectional view along line BB in Figure 7. [Figure 10] Figure 10(a) is a magnified section of Figure 2, and Figure 10(b) is a magnified section of Figure 7. [Figure 11] Figure 11 is a bottom view of the golf club head according to the third embodiment. [Figure 12] Figure 12 is a conceptual diagram illustrating the reference state. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments will be described in detail while referring to the drawings as appropriate.

[0009] In the present application, the following terms are defined.

[0010] [Reference state] The reference state is a state in which the score line and the ground plane HP are parallel and the head is placed on the ground plane HP. In this reference state, the central axis Z (shaft axis) of the shaft hole of the head is arranged within the inclined reference plane SP inclined 6 degrees with respect to the vertical plane VP (see FIG. 12). The vertical plane VP is a plane perpendicular to the ground plane HP. The inclined reference plane SP is a plane that forms an angle of 6 degrees with the vertical plane VP and is inclined 6 degrees toward the face side (front side) with respect to the vertical plane VP. In this reference state, the score line is parallel to the ground plane HP and also parallel to the inclined reference plane SP. This reference state corresponds to the posture of the head when addressed with a 6-degree hand first.

[0011] [Toe - heel direction] In the head in the reference state, the direction of the intersection line between the inclined reference plane SP and the ground plane HP is the toe - heel direction. This toe - heel direction is parallel to the score line.

[0012] [Face - back direction] The direction that is perpendicular to the toe - heel direction and parallel to the ground plane HP is the face - back direction. The face - back direction is also the front - back direction. The face side is also referred to as the front side. The back side is also referred to as the rear side.

[0013] [Vertical direction] The direction that is perpendicular to the toe - heel direction and perpendicular to the face - back direction is the vertical direction.

[0014] [Toe reference position] The position 18 mm away from the most toe - side point in the head towards the heel - side is the toe reference position (see Figure 1). In a general iron - type golf club head, the toe - side end of the score line coincides with the toe reference position. The toe reference position is a position in the toe - heel direction.

[0015] [Heel reference position] Each score line has a heel - side end. Among these heel - side ends, the position of the most heel - side end is the heel reference position. In a general iron - type golf club head, the heel - side end of the longest score line coincides with the heel reference position. The heel reference position is a position in the toe - heel direction.

[0016] [Score line center position] The position that bisects the distance between the toe reference position and the heel reference position is the score line center position. In a general iron - type golf club head, the position at the center 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.

[0017] [Leading edge] In the cross - section of the head along the face - back direction, the most forward - side point is determined. This point is determined at each position in the toe - heel direction. The set of these points is the leading edge. The leading edge is the front edge of the sole surface.

[0018] [Trailing edge] The trailing edge is the rear edge of the sole surface. In the cross - section of the head along the face - back direction, when the radius of curvature of the sole surface is sequentially measured towards the rear, the point at which the radius of curvature first becomes 5 mm or less is determined. The set of these points is defined as the trailing edge.

[0019] [Plan view] A bottom view of the club head, seen from the sole side, is also called a plan view. In other words, a plan view is a projection of the sole surface of the club head in its standard state onto a plane parallel to the ground plane (HP). This projection is a perpendicular projection. The bottom views seen from the sole side, as shown in Figures 2 and 7 described later, are plan views.

[0020] In this application, when determining the radius of curvature of each point on the cross-sectional line, three points are identified: the measurement point and two points 0.5 mm apart on either side of it. The radius of the circle passing through these three points is defined as the radius of curvature of the measurement point. This 0.5 mm is the distance traveled along the cross-sectional line. 0.5 mm is small enough to evaluate the radius of curvature of the measurement point. By setting two points 0.5 mm apart from the measurement point, the radius of curvature at each point on the free curve can be determined without solving the differential equation of the cross-sectional line. This method of determining the radius of curvature is also called the 0.5 mm method.

[0021] The unit of angle in this application is the degree.

[0022] Figure 1 is a front view of the head 100 of the first embodiment, viewed from the face side, and Figure 2 is a bottom view of the head 100, viewed from the sole side. Figure 3 is a cross-sectional view along line AA in Figure 2, and Figure 4 is a cross-sectional view along line BB in Figure 2. Figure 5(a) is an enlarged cross-sectional view of the area enclosed by the rectangular line in Figure 4, and Figure 5(b) is a partially enlarged cross-sectional view at a position along line CC in Figure 2. Note that the scoreline gv is omitted in the cross-sectional views of Figures 4, 5(a), and 5(b).

[0023] The Head 100 is an iron-type golf club head. The Head 100 is not limited to a specific club number.

[0024] The head 100 has a face portion 102, a sole portion 104, and a hosel portion 106. The head 100 has a cavity back.

[0025] The face portion 102 has a striking face 102a. The striking face 102a is also called the face surface. The striking face 102a is a flat surface. When the ball is struck, it hits the striking face 102a. Multiple scorelines gv are formed on the striking face 102a. The distance between adjacent scorelines gv is constant. All scorelines gv are parallel to each other. The scorelines gv include the longest scoreline gv1. Multiple longest scorelines gv1 are provided. The scorelines gv contribute to increasing and stabilizing the amount of backspin.

[0026] Each scoreline gv has a toe-side end 108. In all scorelines gv, the toe-heel position of the toe-side end 108 is aligned.

[0027] Furthermore, the scorelines gv may be provided over almost the entire surface of the striking face 102a. In this case, each scoreline gv extends to the vicinity of the outer edge of the striking face 12a. Therefore, the toe-side end 108 is positioned near the toe-side edge 102t of the striking face 102a. In this configuration, the toe-heel position of the toe-side end 108 is not aligned. This configuration is mainly used in wedges, which are sometimes called full-scoreline wedges. Except in the case of such full-scoreline wedges, the toe-side end of the scoreline can be used as the toe reference position.

[0028] At least one scoreline gv has its furthest heel end 110. In this embodiment, the furthest heel end 110 is the heel end of the longest scoreline gv1. The furthest heel end 110 is located near the heel edge 112 of the striking face 102a. The edge 112 is the boundary between the planar striking face 102a and the non-planar portion 114 that connects to the hosel portion 106. The toe-heel positions of the multiple ends 110 are aligned.

[0029] As described above, the head 100 defines a toe reference position and a heel reference position. As shown in Figure 1, the head 100 has a point P1 that is closest to the toe. The toe reference position t1 is located 18 mm away from this point P1 towards the heel. The toe reference position t1 is a position in the toe-heel direction. In this embodiment, the toe reference position t1 is the position of the toe-side end 108 of each scoreline gv. The heel reference position h1 is the position of the closest heel-side end 110 of the heel-side ends of each scoreline gv. The heel reference position h1 is a position in the toe-heel direction. In this embodiment, the heel-side end of the longest scoreline gv1 is the heel reference position h1.

[0030] As described above, the scoreline center position is defined in Head 100. As shown in Figure 1, the scoreline center position c1 is the position that bisects the space between the toe reference position t1 and the heel reference position h1. The scoreline center position c1 is the position in the toe-heel direction.

[0031] As shown in Figure 2, the sole portion 104 has a sole surface 104a. The sole surface 104a is the surface of the sole portion 104.

[0032] The sole surface 104a has a ridge line 120 and an additional surface 122. The ridge line 120 is a visible line. In a cross-section along the face-back direction, the ridge line 120 forms an angle. In a cross-section along the face-back direction, the radius of curvature of the ridge line 120 may be 5 mm or less. As mentioned above, this radius of curvature is measured using the 0.5 mm method. The ridge line 120 extends from the toe side to the heel side.

[0033] In plan view, the additional surface 122 is an elliptical region. The additional surface 122 is concave. The additional surface 122 is formed to straddle the edge line 120. The width of the additional surface 122 in the toe-heel direction is greater than the width of the additional surface 122 in the face-back direction. The additional surface 122 is located in a position that includes the scoreline center position c1. The entire additional surface 122 is located toe-side than the heel reference position h1. The entire additional surface 122 is located heel-side than the toe reference position t1. The shape of the additional surface 122 in plan view is not limited.

[0034] The additional surface 122 is separated from the leading edge Le. The additional surface 122 does not reach the leading edge Le. The entire additional surface 122 is located behind the leading edge Le. The additional surface 122 is separated from the trailing edge Te. The additional surface 122 does not reach the trailing edge Te. The entire additional surface 122 is located face-side to the trailing edge Te.

[0035] In the region where the added surface 122 exists, the ridge line 120 is interrupted. The ridge line 120 is composed of a heel ridge line 120h located on the heel side of the added surface 122 and a toe ridge line 120t located on the toe side of the added surface 122. The entire toe ridge line 120t is located on the toe side of the scoreline center position c1. The entire heel ridge line 120h is located on the heel side of the scoreline center position c1. The toe ridge line 120t is longer than the heel ridge line 120h.

[0036] The heel ridge 120h has an endpoint 124 on the toe side. The toe ridge 120t has an endpoint 126 on the heel side. In plan view, the line segment G1 connecting endpoints 124 and 126 crosses the additional surface 122. That is, in plan view, the line segment G1 divides the additional surface 122 into two regions. In Figure 2, the line segment G1 is shown as a dashed line.

[0037] The toe-side endpoint 124 of the heel ridge line 120h is located on the outer edge line 122a of the added surface 122. The endpoint 124 does not have to be located on the outer edge line 122a. That is, the endpoint 124 may be located away from the added surface 122. From the viewpoint of enhancing the effect based on the ridge line 120, it is preferable that the ridge line 120 is long. From this viewpoint, the distance between the outer edge line 122a and the endpoint 124 is preferably 5 mm or less, more preferably 3 mm or less, and more preferably 1 mm or less. This distance is measured along the toe-heel direction. As in this embodiment, it is more preferable that this distance is 0 mm. The heel ridge line 120h extends to the heel side beyond the heel reference position h1.

[0038] The heel-side endpoint 126 of the toe ridge 120t is located on the outer edge line 122a of the added surface 122. The endpoint 126 does not have to be located on the outer edge line 122a. That is, the endpoint 126 may be located away from the added surface 122. From the viewpoint of lengthening the ridge 120, the distance between the outer edge line 122a and the endpoint 126 is preferably 5 mm or less, more preferably 3 mm or less, and more preferably 1 mm or less. This distance is measured along the toe-heel direction. As in this embodiment, it is more preferable that this distance is 0 mm. The toe ridge 120t extends to the toe side beyond the toe reference position t1.

[0039] The head 100 has a leading edge Le. As shown in Figure 4, in the cross-section of the head 100 along the face-back direction, there is a point P2 that is located at the foremost position. This point P2 is determined at each position in the toe-heel direction. The set of these points P2 is the leading edge Le. The leading edge Le forms the contour line of the sole surface 104a. The leading edge Le is the leading edge of the sole surface 104a.

[0040] The head 100 has a trailing edge Te. As shown in Figure 4, when the radius of curvature of the sole surface 104a is measured sequentially toward the rear in a cross-section of the head 100 along the face-back direction, a point P3 is determined where the radius of curvature first becomes 5 mm or less. The set of these points P3 is the trailing edge Te. The trailing edge Te constitutes the contour line of the sole surface 104a. The trailing edge Te is the trailing edge of the sole surface 104a.

[0041] The sole surface 104a has a leading surface 130 and a trailing surface 132. The leading surface 130 is formed between the ridge line 120 and the leading edge Le. Furthermore, the leading surface 130 extends between the additional surface 122 and the leading edge Le. The additional surface 122 does not reach the leading surface 130. The trailing surface 132 is formed between the ridge line 120 and the trailing edge Te. Furthermore, the trailing surface 132 extends between the additional surface 122 and the trailing edge Te. The additional surface 122 does not reach the trailing edge Te.

[0042] The leading surface 130 is a convex surface. The leading surface 130 is smooth and continuous as a whole. The leading edge of the leading surface 130 is the leading edge Le. The trailing edge of the leading surface 130 is the ridge line 120. However, in the region where the additional surface 122 exists, the trailing edge of the leading surface 130 is the outer edge line 122a.

[0043] The leading surface 130 has an inclination angle θ1. As shown in Figure 5(b), in a cross-section along the face-back direction, the leading surface 130 has a midpoint M1. The midpoint M1 is the point that bisects the leading surface 130 in the face-back direction. In the head 100 in the reference state, the angle between the tangent line E1 at the midpoint M1 and the ground plane HP is the inclination angle θ1 of the leading surface 130. The angle θ1 may vary depending on the position in the toe-heel direction.

[0044] The trailing surface 132 is a convex surface. The trailing surface 132 is smoothly continuous as a whole. The leading edge of the trailing surface 132 is edge 120. The trailing edge of the trailing surface 132 is trailing edge Te. However, in the region where the additional surface 122 exists, the leading edge of the trailing surface 132 is the outer edge line 122a.

[0045] The trailing surface 132 has an inclination angle θ2. As shown in Figure 5(b), in a cross-section along the face-back direction, the trailing surface 132 has a midpoint M2. The midpoint M2 is the point that bisects the trailing surface 132 in the face-back direction. In the head 100 in the reference state, the angle between the tangent line E2 at the midpoint M2 and the ground plane HP is the inclination angle θ2 of the trailing surface 132. The angle θ2 may vary depending on the position in the toe-heel direction.

[0046] The inclination angles θ1 and θ2 are either positive or negative. If the tangents E1 and E2 are inclined upwards as they move towards the front, the inclination angles θ1 and θ2 are positive. If the tangents E1 and E2 are inclined upwards as they move towards the rear, the inclination angles θ1 and θ2 are negative. In the embodiment shown in Figure 5(b), the inclination angle θ1 is positive and the inclination angle θ2 is negative. There are also cases where the inclination angle θ2 is positive.

[0047] On the sole surface 104a with a ridge line 120, the difference between the inclination angle θ1 and the inclination angle θ2 is large. The inclination angle θ1 is greater than the inclination angle θ2. Also, the inclination angle θ1 is positive. This inclination angle θ1 produces the bounce angle effect (bounce effect). The leading surface 130 with an inclination angle θ1 suppresses the leading edge Le from digging into the ground. Therefore, even if the head trajectory is off, contact with the ball can be stabilized. The inclination angle θ2 is smaller than the inclination angle θ1. Also, the inclination angle θ2 can be a negative value. The trailing surface 132 with an inclination angle θ2 reduces ground resistance and improves release performance. Release performance means less resistance when passing through grass or soil. From these viewpoints, in the region from the toe reference position t1 to the heel reference position h1, the difference (θ1-θ2) can be 5° or more, even 10° or more, and even 15° or more. If this angle difference is excessive, the ground resistance at ridge line 120 may increase. From this perspective, the difference (θ1-θ2) can be set to 35° or less, even 30° or less, and even 25° or less. When angle θ1 is a positive value and angle θ2 is a negative value, the difference (θ1-θ2) is the sum of the absolute values ​​of θ1 and θ2.

[0048] In the region where the additional surface 122 exists, a virtual sole surface 104x and a virtual ridge line 120x are defined. As shown in Figure 5(a), in a cross section along the face-back direction including the additional surface 122, a virtual line F1 extending from the leading surface 130 and a virtual line B1 extending from the trailing surface 132 are determined. An intersection point P4 is determined between virtual line F1 and virtual line B1. Virtual line F1, virtual line B1 and intersection point P4 are determined at each position in the toe-heel direction. The set of virtual lines F1 and virtual line B1 is the virtual sole surface 104x. The set of intersection points P4 is the virtual ridge line 120x. In the region where the additional surface 122 exists, the inclination angles θ1 and θ2 are determined based on the virtual sole surface 104x.

[0049] The virtual line F1 is determined as follows: In a cross-section along the face-back direction, point P5 is defined on the outer edge line 122a of the added surface 122, point P6 is defined 0.5 mm away from point P5 toward the face, and point P7 is defined 0.5 mm away from point P6 toward the face. The virtual line F1 is part of a circle passing through the three points P5, P6, and P7. These 0.5 mm distances are the distances along the cross-sectional line of the sole surface 104a. If points P5, P6, and P7 lie on the same straight line, that straight line is the virtual line F1.

[0050] Similarly, the virtual line B1 is determined as follows: In a cross-section along the face-back direction, point P8 is defined on the outer edge line 122a of the additional surface 122, point P9 is defined 0.5 mm away from point P8 towards the back, and point P10 is defined 0.5 mm away from point P9 towards the back. The virtual line B1 is part of a circle passing through the three points P8, P9, and P10. These 0.5 mm distances are the distances along the cross-sectional line of the sole surface 104a. If points P8, P9, and P10 lie on the same straight line, that straight line is the virtual line B1.

[0051] The method for forming the additional surface 122 is not limited. The additional surface 122 may be formed simultaneously with the leading surface 130 and the trailing surface 132. The additional surface 122 may also be formed after the leading surface 130 and the trailing surface 132 have been formed by grinding away a portion of them.

[0052] Figure 6 is a front view of the head 200 of the second embodiment, viewed from the face side, and Figure 7 is a bottom view of the head 200, viewed from the sole side. Figure 8 is a cross-sectional view along line AA in Figure 7, and Figure 9 is a cross-sectional view along line BB in Figure 7. Note that the scoreline gv is omitted in the cross-sectional view of Figure 9.

[0053] Head 200 is an iron-type golf club head. Head 200 has a face portion 202, a sole portion 204, and a hosel portion 206.

[0054] The face portion 202 has a striking face 202a. The striking face 202a is flat. Multiple scorelines gv are formed on the striking face 202a. The scorelines gv include the longest scoreline gv1.

[0055] As shown in Figure 7, the sole portion 204 has a sole surface 204a. The sole surface 204a has a ridge 220 and an additional surface 222. The ridge 220 extends from the toe side to the heel side.

[0056] In plan view, the additional surface 222 is an elliptical region. The additional surface 222 is a plane. The additional surface 222 is formed to straddle the edge line 220. The width of the additional surface 222 in the toe-heel direction is greater than the width of the additional surface 222 in the face-back direction. The additional surface 222 is located at a position that includes the scoreline center position c1.

[0057] The ridge line 220 has a heel ridge line 220h located on the heel side of the added surface 222 and a toe ridge line 220t located on the toe side of the added surface 222. The heel ridge line 220h has an endpoint 224 on the toe side. The toe ridge line 220t has an endpoint 226 on the heel side. The toe-side endpoint 224 of the heel ridge line 220h is located on the outer edge line 222a of the added surface 222. The heel-side endpoint 226 of the toe ridge line 220t is located on the outer edge line 222a.

[0058] The head 200 has a leading edge Le and a trailing edge Te. The leading edge Le forms the contour line of the sole surface 204a. The trailing edge Te also forms the contour line of the sole surface 204a.

[0059] The sole surface 204a has a leading surface 230 and a trailing surface 232. The leading surface 230 is formed between the ridge line 220 and the leading edge Le. Furthermore, the leading surface 230 extends between the additional surface 222 and the leading edge Le. The additional surface 222 does not reach the leading edge Le. The trailing surface 232 is formed between the ridge line 220 and the trailing edge Te. Furthermore, the trailing surface 232 extends between the additional surface 222 and the trailing edge Te. The additional surface 222 does not reach the trailing edge Te. The leading surface 230 is a convex surface. The trailing surface 232 is a convex surface.

[0060] In Figure 6, the double arrow HL indicates the height (float) of the leading edge Le. This height is also called the leading edge height. This height HL is the height of the lowest point of the leading edge Le from the ground plane HP. The height HL is measured in the above-mentioned standard state. The height HL is measured along the vertical direction. By providing the additional surface 222, the height HL is reduced.

[0061] The heads 100 and 200 described above provide the following effects.

[0062] As mentioned above, in a sole with a ridge, the bounce effect of the leading surface stabilizes contact with the ball, and the trailing surface improves the head's release performance. However, this ridge configuration tends to result in a high leading edge height (HL). By adding an additional surface, the bounce effect can be retained while lowering the leading edge height (HL). This allows for a higher impact point when hitting a ball placed directly on the ground. As a result, the impact point can be brought closer to the face center. A closer impact point to the face center improves rebound performance.

[0063] In the first embodiment, the additional surface 122 is concave, and in the second embodiment, the additional surface 222 is flat. The concave or flat additional surface stabilizes the head's position at address. That is, because the concave or flat surface makes contact with the ground, the head's posture at address is stabilized. This effect is also called the "sit-down effect." From the viewpoint of enhancing the sit-down effect, it is more preferable for the additional surface to be concave.

[0064] When the virtual sole surface 104x is formed, the virtual leading edge height is defined as HL1. The height HL1 is also measured in the reference state. The actual leading edge height HL is lower than the height HL1. The difference (HL1-HL) is the amount of decrease in the leading edge height HL due to the added surface. If this decrease is excessive, the added surface may reach the leading edge Le, and a portion of the leading edge Le may be eroded. From this viewpoint, the decrease in the leading edge height HL is preferably 2.0 mm or less, more preferably 1.9 mm or less, and more preferably 1.8 mm or less. From the viewpoint of increasing the area of ​​the added surface and improving the sitting effect, the decrease in the leading edge height HL is preferably 0.5 mm or more, more preferably 0.6 mm or more, and more preferably 0.7 mm or more.

[0065] From the viewpoint of bringing the point of impact closer to the face center, the leading edge height HL is preferably 5.0 mm or less, more preferably 4.9 mm or less, and even more preferably 4.8 mm or less. From the viewpoint of bounce effect, the leading edge height HL is preferably 3.0 mm or more, more preferably 3.1 mm or more, and even more preferably 3.2 mm or more.

[0066] In Figure 3, the dashed line represents the straight line L1 passing through two points on the outer edge line 122a of the added surface 122. This straight line L1 is a straight line in a specific cross section along the toe-heel direction (a cross section along line AA in Figure 2). The face-back position of this specific cross section is located at the scoreline center position c1 and is determined in the central cross section along the face-back direction (Figure 4). That is, the specific cross section passes through the midpoint M3 of the added surface 122 in the central cross section (see Figure 5(a)). The midpoint M3 is the point that bisects the added surface 122 in the face-back direction. In Figure 3, the double arrow θ3 represents the angle between the straight line L1 and the ground plane HP in the head 100 in the reference state. This angle θ3 is the angle between the added surface 122 and the ground plane HP in the toe-heel direction in the reference state.

[0067] From the viewpoint of the sitting effect, the absolute value of angle θ3 is preferably 10° or less, more preferably 8° or less, and even more preferably 6° or less. The absolute value of angle θ3 may also be 0°.

[0068] In Figure 5(a), the dashed line represents the straight line L2 passing through two points on the outer edge line 122a of the added surface 122. This straight line L2 is the straight line in the central cross-section. In Figure 5(a), the double arrow θ4 represents the angle between the straight line L2 and the ground plane HP in the head 100 in the reference state. This angle θ4 is the angle between the added surface 122 and the ground plane HP in the face-back direction in the reference state.

[0069] From the viewpoint of the seating effect, the absolute value of angle θ4 is preferably 10° or less, more preferably 9° or less, and even more preferably 8° or less. The absolute value of angle θ4 may also be 0°.

[0070] Figure 10(a) is a magnified view of a portion of Figure 2. The additional surface 122 of the head 100 includes a toe portion 122t located toe-side of the scoreline center position c1 and a heel portion 122h located heel-side of the scoreline center position c1. The toe-heel length Dh of the heel portion 122h is greater than the toe-heel length Dt of the toe portion 122t.

[0071] Figure 10(b) is a magnified view of a portion of Figure 7. The additional surface 222 of the head 200 includes a toe portion 222t located toe-side of the scoreline center position c1 and a heel portion 222h located heel-side of the scoreline center position c1. The toe-heel length Dh of the heel portion 222h is greater than the toe-heel length Dt of the toe portion 222t.

[0072] In all embodiments, length Dh is greater than length Dt. In other words, the ratio (Dh / Dt) is greater than 1. It was found that in an actual address position, the toe side of the head is lifted off the ground, and the contact area of ​​the sole surface is closer to the heel. By making Dh greater than Dt, the effect due to the added surface is enhanced. From this viewpoint, the ratio (Dh / Dt) is preferably 1.7 or greater, more preferably 1.8 or greater, and even more preferably 1.9 or greater. If the ratio (Dh / Dt) is too large, the effect of the added surface decreases. The ratio (Dh / Dt) is preferably 2.3 or less, more preferably 2.2 or less, and even more preferably 2.1 or less.

[0073] In Figures 10(a) and 10(b), the double arrow D1 indicates the toe-heel length between the scoreline center position c1 and the heel reference position h1. Length D1 is also the toe-heel length between the scoreline center position c1 and the toe reference position t1. As described above, it is preferable to set the position and range of the additional surface considering the actual address. From this viewpoint, the following are preferable: The ratio (Dh / D1) is preferably 0.40 or more, more preferably 0.45 or more, and more preferably 0.50 or more. The ratio (Dh / D1) is preferably 0.90 or less, more preferably 0.85 or less, and more preferably 0.80 or less. The ratio (Dt / D1) is preferably 0.15 or more, more preferably 0.20 or more, and more preferably 0.25 or more. The ratio (Dt / D1) is preferably 0.50 or less, more preferably 0.45 or less, and more preferably 0.40 or less.

[0074] In a plan view, the area of ​​the additional surfaces 122 and 222 is defined as S1. In Figure 10(b), the area of ​​the portion indicated by solid hatching is S1. Also, in a plan view, the area of ​​the main sole portion m1 is defined as S2. The main sole portion m1 is the portion of the sole surface located between the heel reference position h1 and the toe reference position t1. In Figure 10(b), the area of ​​the portion indicated by dashed hatching is S2.

[0075] From the viewpoint of enhancing the effect of the added surface, the ratio (S1 / S2) is preferably 0.03 or higher, more preferably 0.04 or higher, and even more preferably 0.05 or higher. If the added surface is too wide, the effects of the leading surface and trailing surface may decrease. From this viewpoint, the ratio (S1 / S2) is preferably 0.30 or lower, more preferably 0.20 or lower, and even more preferably 0.15 or lower.

[0076] The added surface may be treated with a surface finish that differs in appearance from the rest of the sole. This treatment makes the contour of the added surface more visible. For example, the added surface may be shot-blasted. In this case, the rest of the sole will be treated with a surface finish that differs in appearance from the shot-blasted surface of the added surface. Examples of such treatments include a mirror finish or a satin finish.

[0077] Figure 11 is a bottom view of the head 300 according to the third embodiment. The head 300 has a sole portion 304 and a hosel portion 306. The sole portion 304 has a sole surface 304a. The sole surface 304a has a ridge 320 and an additional surface 322. The ridge 320 has a toe ridge 320t located on the toe side of the additional surface 322 and a heel ridge 320h located on the heel side of the additional surface 322. Except for the shape of the additional surface 322, the head 300 is the same as the head 100. In the head 300, the additional surface 322 extends to the trailing edge Te. In this case, the ground resistance can be further reduced.

[0078] The club number and loft angle (real loft angle) of the club head are not limited. The present invention can be applied to any iron-type head, for example, long irons, mid-irons, short irons and wedges. The stabilization of contact with the ball, the improvement of turf interaction, the improvement of the point of impact, and the sitting effect are highly effective when the club head speed is high and full shots are taken. From this viewpoint, long irons, mid-irons and short irons are preferred, and long irons and mid-irons are more preferred. The loft angle is preferably 20 degrees or more and less than 60 degrees, more preferably 20 degrees or more and 50 degrees or less, more preferably 20 degrees or more and 40 degrees or less, and more preferably 20 degrees or more and 35 degrees or less.

[0079] The following notes are part of the invention included in this application. [Note 1] A striking face having multiple scorelines, a sole surface, and a rib forming the front edge of the sole surface. De It comprises a trailing edge, a trailing edge that forms the rear edge of the sole surface, and a scoreline center position determined based on the scoreline. The sole surface has a ridge extending from the toe side to the heel side, and an additional surface which is flat or concave and is formed to straddle the ridge. [Note 2] The golf club head according to Appendix 1, wherein the additional surface is the concave surface. [Note 3] The additional surface includes a toe portion located to the toe side of the scoreline center position and a heel portion located to the heel side of the scoreline center position. The golf club head according to Appendix 1 or 2, wherein the toe-heel length of the heel portion is greater than the toe-heel length of the toe portion. [Note 4] When the height of the lowest point of the leading edge from the ground plane in the reference state of the head is defined as the leading edge height, A golf club head according to any one of the appendices 1 to 3, wherein the reduction in the leading edge height due to the added surface is 0.5 mm or more and 2.0 mm or less. [Explanation of Symbols]

[0080] 100, 200, 300... Golf club heads 102, 202... Face section 102a, 202a...Hitting face (face surface) 104, 204, 304... sole 104a, 204a, 304a... sole surface 120, 220, 320...ridgeline 122, 222, 322... Additional surface 122t, 222t... Tow portion of the added surface 122h, 222h... Additional surface heel portion gv...scoreline gv1...Longest scoreline HL... Leading edge height Le···Leading Edge Te···trailing edge

Claims

1. It comprises a striking face having multiple scorelines, a sole surface, a leading edge forming the front edge of the sole surface, a trailing edge forming the rear edge of the sole surface, and a scoreline center position determined based on the scorelines. The sole surface has a ridge extending from the toe side to the heel side and an additional surface that is flat or concave. In the region where the additional surface exists, the ridge line is interrupted. The aforementioned ridge is composed of a heel ridge located on the heel side of the added surface and a toe ridge located on the toe side of the added surface. An iron-type golf club head in which, in a plan view, the line segment connecting the toe-side endpoint of the heel ridge and the heel-side endpoint of the toe ridge intersects the added surface.

2. The golf club head according to claim 1, wherein the additional surface is the concave surface.

3. The additional surface includes a toe portion located to the toe side of the scoreline center position and a heel portion located to the heel side of the scoreline center position. The golf club head according to claim 1 or 2, wherein the toe-heel length of the heel portion is greater than the toe-heel length of the toe portion.

4. When the height of the lowest point of the leading edge from the ground plane in the reference state of the head is defined as the leading edge height, The golf club head according to claim 1 or 2, wherein the reduction in the leading edge height due to the added surface is 0.5 mm or more and 2.0 mm or less.

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