Iron-type golf club head

Abstract

To provide an iron-type golf club head capable of controlling thinning of a face part and handleability of the golf club head.SOLUTION: An iron-type golf club head 10 according to one embodiment of the present disclosure includes a face part 1 and a sole part 2 that extends rearward from a lower edge of the face part 1, and further includes a bridge 8 that has a first end part 8a connected to a rear surface 1b of the face part 1, and a second end part 8b connected behind the face part 1 with a gap with the face part 1. The first end part 8a and the face part 1 are connected within an elliptical region R surrounded by a first circle C1 with a radius of 10 mm centered at a projection point where a centroid of the rear surface 1b of the face part 1 or a centroid of a front surface 1a of the face part 1 is projected onto the rear surface 1b, a second circle C2 with a radius of 10 mm centered at the projection point where a center of gravity of the golf club head is projected onto the rear surface 1b and two line segments L1, L2 circumscribed to the first circle C1 and the second circle C2 and parallel to each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to iron-type golf club heads. [Background technology]

[0002] In iron-type golf club heads, the lower the center of gravity of the head, the easier it is to launch the ball into the air, and the deeper the center of gravity of the head, the greater the forgiveness. Therefore, the lower and deeper the center of gravity of the head, the easier it is to use the iron. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-65468 Summary of the Invention [Problem to be solved by the invention]

[0004] In an iron-type golf club head, in order to lower and deepen the center of gravity of the head, it is effective to reduce the thickness of the face portion.

[0005] Patent Document 1 describes that in an iron-type golf club head, thinning the face portion leads to a poor hitting feel due to a decrease in the rigidity of the face portion. Patent Document 1 also describes that by providing a rib that is connected to the sole portion and disposed on the back surface of the face portion, the hitting feel can be improved while thinning the face portion.

[0006] However, the configuration described in Patent Document 1 has room for further improvement in terms of controlling the thinning of the face portion and ease of handling of the golf club head.

[0007] The present disclosure has been made based on the above circumstances, and one aspect of the present disclosure has an object to provide an iron-type golf club head that is capable of controlling the thinning of the face portion and the ease of handling of the golf club head. [Means for solving the problem]

[0008] (1) An iron-type golf club head according to one embodiment of the present disclosure is an iron-type golf club head including a face portion and a sole portion extending rearward from a lower edge of the face portion, and further including a bridge having a first end portion connected to a rear surface of the face portion and a second end portion connected to the rear of the face portion with a gap therebetween, and the first end portion and the face portion are connected to each other by an elliptical region surrounded by a first circle with a radius of 10 mm centered on the centroid of the rear surface of the face portion or the centroid of the front surface of the face portion projected onto the rear surface, a second circle with a radius of 10 mm centered on the projection point of the center of gravity of the golf club head projected onto the rear surface, and two parallel line segments circumscribing the first circle and the second circle.

[0009] (2) In (1) above, the first end and the face portion may be connected within a first circle having a radius of 10 mm and centered at the projection point of the centroid of the front surface of the face portion projected onto the back surface of the face portion.

[0010] (3) In (1) or (2), the second end is located lower than the first end, and when viewed from behind, an angle between an imaginary line extending vertically through the first end and the central axis of the bridge is 45 degrees or less.

[0011] (4) In the configuration (3) above, the second end may be disposed on the toe side of the imaginary line in a rear view.

[0012] (5) In any one of (1) to (4) above, the bridge may be spaced apart from the face portion over the entire area between the first end and the second end.

[0013] (6) In any one of (1) to (5) above, the second end portion may be connected to the sole portion.

[0014] (7) In any of (1) to (6) above, a rear wall portion may be provided that is spaced apart from the face portion and protrudes upward from the rear end portion of the sole portion, and the second end portion may be connected to the rear wall portion.

[0015] (8) In any of (1) to (7), the bridge has a plate-shaped portion whose longitudinal direction is the direction connecting the first end and the second end, whose thickness direction is the toe-heel direction, and whose width direction is perpendicular to both the longitudinal direction and the thickness direction, and the length of the plate-shaped portion in the width direction is greater than the length in the thickness direction.

[0016] (9) In any of (1) to (8), the bridge may have a first portion extending rearward from the first end and a second portion extending upward from the second end and connected to the first portion.

[0017] (10) In the above (9), the rear edge of the second portion may extend upward from the rear end of the sole portion.

[0018] (11) In any of (1) to (10), the bridge may have an enlarged diameter portion provided around the first end so as to increase the diameter of the first end and connected to the back surface of the face portion.

[0019] (12) In the above (11), the enlarged diameter portion may have a circular abutment surface with the back surface of the face portion.

[0020] In this disclosure, "front" means the side to be hit, and "rear" means the opposite side. "Front of face" means the area of ​​the front of the golf club head that is toe side of the boundary line of the toe side of the heel part (see the area in the thick frame in FIG. 5). "Rear of face" means the flat surface facing the front of the face (see the area surrounded by the thick solid line and the thick broken line in FIG. 6). Also, "flat surface" includes a shape having irregularities with a height or depth of 0.5 mm or less. "Projection point of the center of gravity of the golf club head projected on the rear" means a projection point of the center of gravity of the golf club head projected in the normal direction of the front of the face part with respect to the rear of the face part. "Rear view" means a rear view in a state where the iron-type golf club head is placed on a horizontal plane so as to have a predetermined lie angle and loft angle (the inherent lie angle and loft angle determined for the iron-type golf club head). The "toe-heel direction" means a horizontal direction perpendicular to the front-to-rear direction when the iron-type golf club head is placed on a horizontal plane to have a predetermined lie angle and loft angle. "The rear edge of the second part extends upward from the rear end of the sole part" includes a configuration in which the rear edge of the second part extends directly from the rear end of the sole part, and a configuration in which a rear wall part protrudes from the rear end of the sole part and the rear edge of the second part extends from this rear wall part. Effect of the Invention

[0021] The iron-type golf club head according to one embodiment of the present disclosure includes the bridge, which can suppress the deflection of the face portion during impact. Therefore, even if the face portion is thinned, the iron-type golf club head can suppress cracks and dents in the face portion. Furthermore, since the second end portion is disposed at a distance from the face portion in the iron-type golf club head, the center of gravity of the entire golf club head can be easily deepened while homogenizing the repulsion performance of the face portion. Therefore, the iron-type golf club head can control the thinning of the face portion and the ease of handling of the golf club head. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic front view (front view) showing an iron-type golf club head according to one embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic rear view of the iron-type golf club head of FIG. [Diagram 3] FIG. 3 is a schematic perspective view of the iron-type golf club head of FIG. 1 as viewed from the rear side. [Figure 4] FIG. 4 is a cross-sectional view of the iron-type golf club head of FIG. 2 taken along line IV-IV. [Diagram 5] FIG. 5 is a schematic diagram for explaining the front surface of the face portion of the iron-type golf club head of FIG. [Figure 6] FIG. 6 is a schematic diagram for explaining the rear surface of the face portion of the iron type golf club head of FIG. [Figure 7] FIG. 7 is a schematic rear view showing a modification of the iron-type golf club head of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. It is possible to adopt only one of the upper limit value and the lower limit value described in the present specification, or to arbitrarily combine the upper limit value and the lower limit value. In this specification, it is assumed that all combinable numerical ranges are described as suitable ranges. In addition, each figure is a schematic diagram and may not match the actual dimensions, ratios, etc. In this disclosure, the descriptions "first" and "second" are intended to distinguish the components to which they are attached, and do not limit the number, order, priority, etc.

[0024] [First embodiment] <Iron-type golf club head> An iron-type golf club head 10 (hereinafter, simply referred to as "golf club head 10") of Figs. 1 to 4 includes a face portion 1 and a sole portion 2 extending rearward from a lower edge of the face portion 1. The golf club head 10 also includes a top portion 3 extending rearward from an upper edge of the face portion 1, a toe portion 4 extending rearward from a toe side (tip side) of the face portion 1, a heel portion 5 provided on a heel side (opposite the tip side) of the face portion 1, and a bosel portion 6 provided continuously with the heel portion 5. The golf club head 10 also includes a rear wall portion 7 that is spaced apart from the face portion 1 and protrudes upward from a rear end portion of the sole portion 2. As shown in Figs. 3 and 4, the golf club head 10 includes a bridge 8 having a first end portion 8a connected to a back surface 1b of the face portion 1 and a second end portion 8b connected to the rear of the face portion 1 with a gap therebetween. The first end 8a and the face portion 1 are connected by an elliptical region R surrounded by a first circle C1 with a radius of 10 mm centered on a projection point G1 obtained by projecting the centroid (not shown) of the back surface 1b of the face portion 1 or the centroid G of the front surface 1a of the face portion 1 onto the back surface 1b, a second circle C2 with a radius of 10 mm centered on a projection point G2 obtained by projecting the center of gravity (not shown) of the golf club head onto the back surface 1b, and two parallel line segments L1 and L2 circumscribing the first circle C1 and the second circle C2. The first circle C1 is a virtual circle drawn on the back surface 1b of the face portion 1 with the projection point G1 as its center. The second circle C2 is a virtual circle drawn on the back surface 1b of the face portion 1 with the projection point G2 as its center.

[0025] The golf club head 10 is used as an iron-type golf club with a shaft (not shown) connected to the ball section 6. The iron-type golf club is one embodiment of the present disclosure.

[0026] The golf club head 10 includes the bridge 8, which can suppress the bending of the face portion 1 during impact. Therefore, even if the face portion 1 is thinned, the golf club head 10 can suppress cracks and dents in the face portion 1. In addition, since the second end portion 8b of the golf club head 10 is disposed at a distance from the face portion 1, the center of gravity of the entire golf club head can be easily deepened while homogenizing the repulsion performance of the face portion 1. In other words, if the front edge portion of the bridge (or rib) is in close contact with the face portion over the entire area between the first end portion and the second end portion, the bending of the face portion is restricted, which tends to make the repulsion performance of each portion of the face portion uneven. In contrast, the golf club head 10 can homogenize the repulsion performance of the entire face portion 1, which can improve the ease of handling of the golf club head. In addition, since the golf club head 10 has a gap between the face portion 1 and the bridge 8, the center of gravity of the bridge 8 itself tends to be located at the rear of the golf club head. Therefore, the golf club head 10 can control the thinning of the face portion 1 and the ease of handling of the golf club head.

[0027] The golf club head 10 may have a lower and deeper center of gravity for the entire golf club head. Such a golf club head may be preferred for its ease of use. In this regard, the golf club head 10 can further improve ease of use by homogenizing the repulsion performance of the entire golf club head.

[0028] The golf club head 10 is mainly composed of a metal or alloy such as iron or stainless steel. That is, the bridge 8 can be formed mainly of a metal or alloy such as iron or stainless steel. Here, the term "main component" refers to the component with the largest content by mass.

[0029] (Face) The face portion 1 has a front surface 1a (see the area within the thick frame in FIG. 5) that constitutes a hitting surface, and a back surface 1b (see the area surrounded by the thick solid line and the thick broken line in FIG. 6) on the opposite side of the front surface 1a. A plurality of scorelines 11 are provided on the front surface 1a. The plurality of scorelines 11 extend in the toe-heel direction at intervals in the up-down direction.

[0030] The upper limit of the thickness T of the face portion 1 (plate thickness between the front surface 1a and the rear surface 1b; see FIG. 4) is not particularly limited, but is preferably 1.9 mm, more preferably 1.7 mm, and even more preferably 1.5 mm. Since the golf club head 10 includes the bridge 8, even if the thickness T of the face portion 1 is set to be equal to or less than the upper limit, cracks and dents in the face portion 1 can be suppressed. On the other hand, the lower limit of the thickness T can be set to, for example, 1.0 mm, from the viewpoint of providing the face portion 1 with sufficient durability.

[0031] (Sole) The sole portion 2 extends rearward from the lower edge of the face portion 1, and is connected at its toe-side end to the toe portion 4 and at its heel-side end to the heel portion 5. The sole portion 2 is in the form of a thin plate with the toe-heel direction as its longitudinal direction and the front-to-rear direction as its width direction.

[0032] 2 to 4, the sole portion 2 has a groove 2a extending in the toe-heel direction. The groove 2a reduces the weight of the sole portion 2, increasing the degree of freedom in weight distribution of the entire golf club head.

[0033] 3 and 4, the groove 2a may be directly connected to the back surface 1b of the face portion 1. In other words, the back surface 1b of the face portion 1 may also serve as the front side surface of the groove 2a. With this configuration, the weight of the sole portion 2 can be made sufficiently small.

[0034] (rear wall) The rear wall portion 7 is disposed behind the face portion 1 and spaced apart from it, thereby contributing to a deeper center of gravity of the golf club head 10. The rear wall portion 7 is also connected to the sole portion 2, thereby contributing to a lower center of gravity of the golf club head 10. The front surface of the rear wall portion 7 also serves as the rear side surface of the groove 2a. The rear wall portion 7 has a high rigidity portion 7a on the toe side in the toe-heel direction, which has greater rigidity than other portions. The high rigidity portion 7a is, for example, an extended portion whose cross-sectional area perpendicular to the toe-heel direction is extended.

[0035] (bridge) As shown in FIG. 3 and FIG. 4, the bridge 8 has a first end 8a located at the front end and a second end 8b located at the lower end. The first end 8a of the bridge 8 is connected to the back surface 1b of the face portion 1, and the second end 8b is connected to the rear of the face portion 1, and the portion between the first end 8a and the second end 8b is disposed at a distance from the face portion 1. It is preferable that the bridge 8 is spaced apart from the face portion 1 over the entire area between the first end 8a and the second end 8b. With this configuration, the deflection of the face portion 1 is less likely to be restricted by the bridge 8, and the repulsion performance of the face portion 1 is easily maintained uniformly. In addition, the weight of the entire golf club head is easily shifted backward, making it easier to achieve a deeper center of gravity of the golf club head 10.

[0036] As shown in Figs. 3 and 4, a gap 12 extending upward from the sole portion 2 is provided between the bridge 8 and the back surface 1b of the face portion 1 (more specifically, between a second portion 22 described below and the back surface 1b of the face portion 1). The gap 12 is elongated, for example, with the vertical direction as the longitudinal direction. The lower edge of the gap 12 is defined by the sole portion 2, and the upper edge of the gap 12 is defined by a first portion 21 of the bridge 8 described below. The gap 12 is provided to have a size such that the face portion 1 and the bridge 8 do not come into contact with each other when the face portion 1 is deflected upon impact.

[0037] As shown in FIG. 3 and FIG. 4, the bridge 8 has a main body 13 connecting the first end 8a and the second end 8b, and an expanded diameter portion 14 provided by expanding from the peripheral surface of the first end 8a. The main body 13 may be a plate-shaped portion having a longitudinal direction in the direction connecting the first end 8a and the second end 8b, a thickness direction in the toe-heel direction, and a width direction perpendicular to both the longitudinal direction and the thickness direction. The plate-shaped portion is, for example, flat. The length of the width direction of this plate-shaped portion may be greater than the length of the thickness direction. Since the bridge 8 has the plate-shaped portion, it can easily suppress the deflection of the face portion 1 at the time of impact. In addition, according to this configuration, it is possible to suppress the weight of the bridge 8 from becoming too large, and it is easy to increase the degree of freedom of weight distribution of the entire golf club head.

[0038] The enlarged diameter portion 14 is provided around the first end portion 8a so as to increase the diameter of the first end portion 8a, and is connected to the back surface 1b of the face portion 1. The golf club head 10 has the enlarged diameter portion 14, which makes it possible to prevent the stress applied to the face portion 1 from becoming locally large. As a result, cracks and dents in the face portion 1 can be more easily prevented.

[0039] The shape of the contact surface of the expanded diameter portion 14 with the back surface 1b of the face portion 1 may be a circle, a polygon, or the like. Among them, a circle is preferable because it can promote homogenization of the stress applied to the face portion 1. In this disclosure, the term "circle" includes a perfect circle, an ellipse, an oval, and the like, and among these, a perfect circle is preferable.

[0040] The lower limit of the average diameter of the enlarged diameter portion 14 is preferably 10 mm, more preferably 15 mm, and even more preferably 17 mm, from the viewpoint of homogenizing the stress applied to the face portion 1. On the other hand, the upper limit of the average diameter is preferably 30 mm, more preferably 25 mm, from the viewpoint of suppressing a substantial increase in the thickness of the face portion 1 due to the enlarged diameter portion 14. Here, the "average diameter" means the diameter converted into a perfect circle.

[0041] The diameter of the expanded diameter portion 14 may gradually increase toward the back surface 1b of the face portion 1. An example of such a shape is a trumpet shape. By configuring the expanded diameter portion 14 in this manner, it is possible to suppress a substantial increase in the thickness of the face portion 1 due to the expanded diameter portion 14, and to easily homogenize the stress applied to the face portion 1.

[0042] As described above, the first end 8a of the bridge 8 is connected to the back surface 1b of the face portion 1 through the oval region R. More specifically, at least a portion of the first end 8a of the main body 13 (a plate-shaped portion in this embodiment) is connected to the back surface 1b of the face portion 1 through the oval region R.

[0043] The first end 8a is selectively connected to the back surface 1b of the face portion 1 at a position suitable for suppressing the bending of the face portion 1. More specifically, in an iron-type golf club, when the face portion 1 bends around the shaft and the heel portion 5 continuing from the shaft, the centroid G of the front surface 1a of the face portion 1 can be the part of the face portion 1 that is most likely to vibrate. Also, the contact area of ​​the front surface 1a of the face portion 1 with the ball at the time of impact is usually a circle with a radius of about 10 mm. Therefore, the first circle C1 corresponds to the area that is most likely to vibrate at the time of impact of the ball. Also, for example, when the lateral moment of inertia is increased in the golf club head 10, the rigidity in the vicinity of the projection point G2 may be reduced. Therefore, the second circle C2 corresponds to the area where the face portion 1 is most likely to vibrate. From these points, it is found that the elliptical region R surrounded by the first circle C1, the second circle C2, and two parallel line segments L1, L2 circumscribing these two circles C1, C2 corresponds to the region of the face portion 1 in the golf club head 10 that is prone to vibration.

[0044] It is preferable that the first end 8a and the face portion 1 are connected within a first circle C1 having a radius of 10 mm and centered on a projection point G1 obtained by projecting the centroid G of the front surface 1a of the face portion 1 onto the back surface 1b of the face portion 1. It is also preferable that the projection point G1 is included in the connection portion between the first end 8a and the face portion 1. With this configuration, it is possible to easily suppress the deflection of the face portion 1 at the time of impact. As a result, it is possible to more easily make the face portion 1 thinner.

[0045] The second end 8b is located lower than the first end 8a. In addition, the second end 8b is connected to the sole portion 2. By connecting the second end 8b to the sole portion 2 in this manner, it becomes easier to freely design the configuration of the entire golf club head.

[0046] When the second end 8b is connected to the sole portion 2, the second end 8b may be connected to the rear end of the sole portion 2 (the rear end of the groove 2a in this embodiment). This configuration makes it easy to increase the length of the bridge 8 in the front-to-rear direction. As a result, it is possible to more reliably suppress the deflection of the face portion 1 at the time of impact.

[0047] The second end 8b is connected to the rear wall portion 7. That is, in this embodiment, the second end 8b is connected to both the sole portion 2 and the rear wall portion 7. In the golf club head 10, since the second end 8b is connected to the rear wall portion 7, the length of the bridge 8 in the front-to-rear direction is increased and the bridge 8 can be supported from the rear by the rear wall portion 7. As a result, the deflection of the face portion 1 at the time of impact can be more easily and reliably suppressed.

[0048] 2, in rear view, the angle α between an imaginary line V that passes through the first end 8a and extends vertically and the central axis of the bridge 8 (the central axis of the main body 13) is preferably 45 degrees or less, and more preferably 35 degrees or less, from the viewpoint of promoting a lower center of gravity of the golf club head. In other words, when the angle α is defined as + when the central axis is inclined toward the toe side from the imaginary line V and - when the central axis is inclined toward the heel side, it is preferably within a range of -45 degrees or more and +45 degrees or less, and more preferably within a range of -35 degrees or more and +35 degrees or less.

[0049] In the rear view, the second end 8b may be disposed on the imaginary line V or on the toe side of the imaginary line V, and is more preferably disposed on the toe side of the imaginary line V. That is, the angle α may be 0 degrees or more and +45 degrees or less, and is more preferably more than 0 degrees and +45 degrees or less. The upper limit of the angle α may be 35 degrees. In the golf club head 10, the second end 8b is disposed on the toe side of the imaginary line V, and therefore the second end 8b can be connected to a portion where stress is less likely to concentrate during impact. As a result, the effect of the bridge 8 in suppressing the deflection of the face portion 1 can be further enhanced.

[0050] In addition, in the toe-heel direction in rear view, the second end 8b may be disposed between both ends of the enlarged diameter portion 14. This configuration prevents the bridge 8 from becoming too long, and makes it easy to increase the degree of freedom in weight distribution of the entire golf club head.

[0051] As shown in Fig. 4, the bridge 8 has a first portion 21 extending rearward from a first end portion 8a. The bridge 8 also has a second portion 22 extending upward from a second end portion 8b and connected to the first portion 21. This configuration makes it possible to increase the length of the portion extending rearward from the back surface 1b of the face portion 1. As a result, it is possible to more reliably suppress the deflection of the face portion 1 at the time of impact.

[0052] It is preferable that the first portion 21 extends in a direction perpendicular to the back surface 1b of the face portion 1. This configuration makes it easier to improve the effect of suppressing the deflection of the face portion 1. Note that "the first portion extends in a direction perpendicular to the back surface of the face portion" means that the angle between the back surface of the face portion and the central axis of the first portion is 80 degrees or more and 90 degrees or less, preferably 85 degrees or more and 90 degrees or less, and more preferably 90 degrees.

[0053] The rear edge portion of the second portion 22 extends upward from the rear end portion of the sole portion 2. With this configuration, the length of the first portion 21 can be easily increased.

[0054] [Second embodiment] <Iron-type golf club head> The iron-type golf club head 30 in Fig. 7 (hereinafter, also simply referred to as "golf club head 30") includes the golf club head 10 in Figs. 1 to 4 and a lid portion 40 that closes a rear opening of the golf club head 10 (an opening defined by the inner peripheral edges of the top portion 3, the toe portion 4, the heel portion 5 and the rear wall portion 7). In the golf club head 30, the rear end edge of the bridge 8 (more specifically, the rear end edge of the second portion 22) is exposed from the lid portion 40. The lid portion 40 has a notch 41 for exposing the bridge 8.

[0055] In the golf club head 30, the bridge 8 is exposed from the cover portion 40, so that the length of the bridge 8 in the front-rear direction is large. Therefore, the golf club head 30 can easily and reliably suppress the bending of the face portion 1 at the time of impact.

[0056] [Other embodiments] The above-described embodiments do not limit the configuration of the present invention. Therefore, the above-described embodiments may include omissions, substitutions, or additions of components of each part of the embodiments based on the description in this specification and common technical knowledge, and all of these should be interpreted as falling within the scope of the present invention.

[0057] From the viewpoint of increasing the degree of freedom in weight distribution of the entire golf club head, it is preferable that the golf club head has only a single bridge. It is also preferable that no members other than the bridge (e.g., ribs, etc.) are arranged on the back surface of the face portion. However, it is also possible to arrange other members on the back surface of the face portion within a range that allows the desired quality to be maintained in an iron-type golf club head.

[0058] From the viewpoint of promoting a lower center of gravity of the entire golf club head, it is preferable that the angle between the imaginary line V and the center axis of the bridge is 45 degrees or less. However, the golf club head can improve the degree of freedom of weight distribution of the entire golf club head by thinning the face portion. Therefore, the angle can be set according to the quality required for the golf club head.

[0059] The bridge is preferably designed to not constrain flexure of the face, although this disclosure is not intended to exclude configurations in which a portion of the bridge between the first and second ends contacts the back surface of the face.

[0060] In the above embodiment, the second end portion is connected to both the sole portion and the rear wall portion. However, the second end portion may be connected only to the sole portion or only to the rear wall portion. Furthermore, the second end portion may be connected to the toe portion or the heel portion as long as the quality required for the golf club head can be satisfied.

[0061] The shape of the body of the bridge is not limited to the plate-like portion described above. For example, the body may be a round bar. Even if the body is a plate-like portion, the length in the width direction of the plate-like portion may be equal to or less than the length in the thickness direction.

[0062] The bridge may be shaped so as not to have either or both of the first and second parts. For example, the bridge may be provided so as to linearly connect the back surface of the face part and the rear wall part. Also, another part may be disposed between the first and second parts.

[0063] The bridge may be configured without the enlarged diameter portion so long as cracks or dents in the face portion can be suppressed.

[0064] The specific configuration of the sole part is not limited to the configuration described in the above embodiment. For example, the sole part may not have a groove extending in the toe-heel direction. Even if the sole part has a groove, the groove may be formed, for example, at a position away from the back surface of the face part. EXAMPLES

[0065] Hereinafter, the present disclosure will be described in detail based on examples, but the present disclosure should not be construed as being limited based on the description of these examples.

[0066] (Iron type golf club head) Iron-type golf club heads No. 1 and No. 2 were prepared. Golf club head No. 2 does not have a bridge on the back surface of the face. Golf club head No. 1 has the same structure as golf club head No. 2, except that it has a bridge on the back surface of the face. The bridge in golf club head No. 1 has the shape shown in Figs. 1 to 4. The first end of this bridge is located at the projection point of the centroid of the front surface of the face onto the back surface of the face. This bridge has an enlarged diameter portion around the periphery of the first end. The contact surface of this enlarged diameter portion with the back surface of the face is a perfect circle. The diameter of this enlarged diameter portion is 20 mm.

[0067] (Durability test) A set number of golf balls were hit directly against the golf club heads No. 1 and No. 2, and the golf club head No. 1 did not develop any cracks or dents in the face even though the face thickness was 1.3 mm. On the other hand, the golf club head No. 2 developed cracks and dents in the face when the face thickness was made less than 2.0 mm. The results of this durability test are shown in Table 1.

[0068] [Table 1]

[0069] As shown in Table 1, the No. 1 golf club head with a bridge has a face thickness that is 0.7 mm thinner than the No. 2 golf club head. As a result, the weight of the golf club head is reduced by 10.3 g. This shows that providing a bridge on the back surface of the face makes it possible to achieve both a thinner face and control of the center of gravity of the golf club head. [Explanation of symbols]

[0070] 1 Face section 1a Front 1b Back 2 Sole 2a groove 3 Top Section 4 Toe 5 Heel 6 Bosel Club 7 Rear wall 7a High rigidity part 8. Bridge 8a 1st end 8b Second end 10, 30 Iron type golf club head 11 Scoreline 12 void 13 Main unit 14 Expanded diameter part 21 Part 1 22 Part 2 40 Lid 41 Notch C1 First Circle C2 Second Circle G Center of the front of the face G1 Projection point of the center of the front face of the face part onto the back face G2 Projection point of the center of gravity of the golf club head onto the back of the face L1, L2 Line segments circumscribing the first and second circles R Elliptical area T Face thickness V: An imaginary line passing through the first end and extending vertically α is the angle between an imaginary line passing through the first end and extending vertically and the central axis of the bridge

Claims

1. An iron-type golf club head including a face portion and a sole portion extending rearward from a lower edge of the face portion, a bridge having a first end connected to a back surface of the face portion and a second end connected to a rear side of the face portion with a space therebetween; The first end and the face portion are connected by an elliptical region surrounded by a first circle having a radius of 10 mm and centered on the centroid of the back surface of the face portion or the centroid of the front surface of the face portion projected onto the back surface, a second circle having a radius of 10 mm and centered on the projection point of the center of gravity of the golf club head projected onto the back surface, and two parallel line segments circumscribing the first circle and the second circle. Iron type golf club head.

2. 2. The iron-type golf club head according to claim 1, wherein the first end and the face portion are connected within a first circle having a radius of 10 mm and centered at a projection point obtained by projecting the centroid of the front surface of the face portion onto the rear surface of the face portion.

3. The second end is located below the first end, 3. The iron-type golf club head according to claim 1, wherein an angle between an imaginary line passing through said first end and extending in a vertical direction and a central axis of said bridge is 45 degrees or less in rear view.

4. 4. The iron-type golf club head according to claim 3, wherein the second end is located on the toe side of the imaginary line in a rear view.

5. 3. The iron-type golf club head according to claim 1, wherein the bridge is spaced apart from the face portion over the entire area between the first end and the second end.

6. 3. The iron-type golf club head according to claim 1, wherein the second end is connected to the sole portion.

7. a rear wall portion spaced apart from the face portion and protruding upward from a rear end portion of the sole portion, 3. The iron-type golf club head according to claim 1, wherein the second end is connected to the rear wall portion.

8. The bridge has a plate-shaped portion having a longitudinal direction in a direction connecting the first end and the second end, a thickness direction in a toe-heel direction, and a width direction perpendicular to both the longitudinal direction and the thickness direction, 3. The iron-type golf club head according to claim 1, wherein the length in the width direction of the plate-like portion is greater than the length in the thickness direction of the plate-like portion.

9. 3. The iron-type golf club head according to claim 1, wherein the bridge has a first portion extending rearward from the first end and a second portion extending upward from the second end and connected to the first portion.

10. 10. The iron-type golf club head according to claim 9, wherein the rear edge of the second portion extends upward from the rear end of the sole portion.

11. 3. The iron-type golf club head according to claim 1, wherein the bridge has an enlarged diameter portion provided around the first end so as to increase the diameter of the first end and connected to a back surface of the face portion.

12. 12. The iron-type golf club head according to claim 11, wherein the enlarged diameter portion has a circular abutment surface with the rear surface of the face portion.

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