Iron-type golf club head

Abstract

The purpose of the present disclosure is to provide an iron-type golf club head capable of controlling the thickness of a club face part and the ease of operation of the golf club head. An iron-type golf club head according to one embodiment of the present disclosure is provided with a face section, a bottom section extending rearward from the lower edge of the face section, and a bridge section having a first end section connected to the back surface of the face section, and a second end section connected to the rear of the face section at a distance from the face section. The first end portion and the face portion are connected in an oblong region. The first circle has a radius of 10 mm centered on a projection point at which the centroid of the back surface of the face part or the centroid of the front surface of the face part is projected onto the back surface; the second circle has a radius of 10 mm centered on a projection point at which the center of gravity of the golf club head is projected onto the back surface; the two line segments are externally tangent to the first circle and the second circle and are parallel to each other.

Description

Technical Field

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

[0002] In an iron-type golf club head, the lower the center of gravity of the club head is, the easier it is for the ball to rise, and the deeper the center of gravity of the club head is, the higher the tolerance is. Therefore, the lower and deeper the center of gravity of the club head is, the easier it is to operate the iron.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: (Japanese) Patent Publication No. 2022-65468 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] In an iron-type golf club head, in order to lower the center of gravity of the club head and deepen the center of gravity of the club head, it is effective to reduce the thickness of the face portion.

[0008] Patent Document 1 states that in an iron-type golf club head, if the face portion is thinned, the rigidity of the face portion is reduced, resulting in a poor hitting feel. Patent Document 1 states that by providing a rib connected to the sole and arranged on the back of the face portion, the face portion can be thinned and the hitting feel can be improved.

[0009] However, from the viewpoint of thinning the face portion and controlling the ease of handling of the golf club head, the structure described in Patent Document 1 has room for further improvement.

[0010] The present disclosure has been made based on such circumstances, and an object of one aspect of the present disclosure is to provide an iron-type golf club head capable of controlling the thinning of the face portion and the ease of handling of the golf club head.

[0011] Technical solutions for solving technical problems

[0012] (1) An iron-type golf club head according to one aspect of the present disclosure comprises a club face portion and a sole portion extending rearward from a lower edge of the club face portion, and comprises a bridge portion having a first end portion connected to the back surface of the club face portion and a second end portion connected to the rear of the club face portion at a distance from the club face portion, wherein the first end portion and the club face portion are connected in an oblong area, and the oblong area is surrounded by a first circle with a radius of 10 mm centered at a projection point of the back surface of the club face portion or the centroid of the front surface of the club face portion projected onto the back surface, a second circle with a radius of 10 mm centered at a 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.

[0013] (2) In (1) above, the first end portion and the face portion may be connected within a first circle having a radius of 10 mm centered at a projection point obtained by projecting the centroid of the front surface of the face portion onto the back surface of the face portion.

[0014] (3) In (1) or (2), the second end portion may be located below the first end portion, and when viewed from behind, an angle formed by an imaginary line passing through the first end portion and extending in the vertical direction and the central axis of the bridging portion is less than 45 degrees.

[0015] (4) In the above (3), the second end portion may be arranged on the toe side of the imaginary line in a rear view.

[0016] (5) In any one of the above aspects (1) to (4), the bridge portion may be separated from the face portion over the entire region between the first end portion and the second end portion.

[0017] (6) In any one of the above aspects (1) to (5), the second end portion may be connected to the bottom portion.

[0018] (7) In any one of the above aspects (1) to (6), a rear wall portion may be provided which is separated from the face portion and rises upward from a rear end portion of the sole portion, and the second end portion may be connected to the rear wall portion.

[0019] (8) In any one of the aspects (1) to (7), the bridging portion may include a plate-like portion having a length direction in a direction connecting the first end portion and the second end portion, a thickness direction in a toe-to-heel direction, and a width direction perpendicular to both the length direction and the thickness direction, wherein the length of the plate-like portion in the width direction is greater than the length in the thickness direction.

[0020] (9) In any one of the above aspects (1) to (8), the bridge portion may include a first portion extending rearward from the first end portion and a second portion extending upward from the second end portion and connected to the first portion.

[0021] (10) In the above (9), the rear end edge of the second portion may extend upward from the rear end portion of the bottom portion.

[0022] (11) In any one of the above aspects (1) to (10), the bridge portion may include an expanded diameter portion provided around the first end portion so as to increase the diameter of the first end portion and connected to the back surface of the face portion.

[0023] (12) In the above (11), the contact surface between the enlarged diameter portion and the back surface of the face portion may be circular.

[0024] It should be noted that in the present disclosure, "front" refers to the side on which the ball is struck, and "rear" refers to the opposite side. "Front face" refers to the area on the toe side of the front face of the golf club head that is closer to the toe side than the boundary line on the toe side of the heel (see Figure 5 The “back side of the club face” refers to the flat surface opposite to the front side of the club face (see the area in the bold frame). Figure 6 The term "flat surface" refers to the area surrounded by thick solid lines and thick dotted lines). In addition, the "flat surface" includes a shape with a concave-convex shape with a height or depth of 0.5 mm or less. "The projection point of the center of gravity of the golf club head onto the back surface" refers to the projection point of the center of gravity of the golf club head in the normal direction in front of the club face relative to the back surface of the club face. "Rear view" refers to the rear view of the iron-type golf club head arranged in a horizontal plane in a manner to achieve a specified elevation angle and inclination angle (the inherent elevation angle and inclination angle specified in the iron-type golf club head). "Toe-heel direction" refers to the horizontal direction orthogonal to the front-to-back direction in a state in which the iron-type golf club head is arranged in a horizontal plane in a manner to achieve a specified elevation angle and inclination angle. "The rear end edge of the second part extends upward from the rear end portion of the bottom" includes: a structure in which the rear end edge of the second part extends directly from the rear end portion of the bottom; and a structure in which the rear wall portion bulges from the rear end portion of the bottom, and the rear end edge of the second part extends from the rear wall portion.

[0025] Effects of the Invention

[0026] The iron-type golf club head of one aspect of the present disclosure is provided with the bridge portion, which can suppress the bending of the club face when hitting. Therefore, even if the wall of the club face is thinned, the iron-type golf club head can suppress cracks and depressions on the club face. In addition, the second end of the iron-type golf club head is arranged at a distance from the club face, so that the rebound performance of the club face can be homogenized, and the center of gravity of the golf club head as a whole can be easily deepened. Therefore, the iron-type golf club head can control the thinning of the club face and the ease of operation of the golf club head. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic front view (front view) showing an iron-type golf club head according to an embodiment of the present disclosure.

[0028] Figure 2 yes Figure 1 A schematic rear view of an iron-type golf club head.

[0029] Figure 3 is from Figure 1 Schematic perspective view of an iron-type golf club head as viewed from the back side.

[0030] Figure 4 yes Figure 2 A cross-sectional view of an iron-type golf club head along line IV-IV.

[0031] Figure 5 It is used to illustrate Figure 1 Schematic diagram of the front of the club face of an iron-type golf club head.

[0032] Figure 6 It is used to illustrate Figure 1 Schematic diagram of the back side of the club face of an iron-type golf club head.

[0033] Figure 7 Yes means Figure 1 A schematic rear view of a modified example of an iron-type golf club head. DETAILED DESCRIPTION

[0034] Hereinafter, the embodiments of the present disclosure will be described in detail with appropriate reference to the accompanying drawings. It should be noted that, for the numerical values ​​recorded in this specification, only one of the upper limit value and the lower limit value recorded may be adopted, or the upper limit value and the lower limit value may be arbitrarily combined. In this specification, all numerical ranges that can be combined are recorded as appropriate ranges. In addition, the figures are schematic and there are cases where they are inconsistent with actual dimensions, ratios, etc. In the present disclosure, the records of "first" and "second" are used to distinguish the constituent elements assigned with "first" and "second", and are not used to limit quantity, order, priority, etc.

[0035] [First embodiment]

[0036] <Iron-type golf club heads>

[0037] Figures 1 to 4 An iron-type golf club head 10 (hereinafter, also simply referred to as "golf club head 10") includes a club face portion 1 and a sole portion 2 extending rearward from the lower edge of the club face portion 1. In addition, the golf club head 10 includes: a top portion 3 extending rearward from the upper edge of the club face portion 1; a toe portion 4 extending rearward from the toe side (front end side) of the club face portion 1; a heel portion 5 provided on the heel side (opposite side to the front end side) of the club face portion 1; and a neck portion 6 provided continuously with the heel portion 5. Furthermore, the golf club head 10 includes a rear wall portion 7 which is separated from the club face portion 1 and bulges upward from the rear end portion of the sole portion 2. Figure 3 and Figure 4 As shown in FIG. 1 , the golf club head 10 includes a bridge portion 8 having a first end portion 8a connected to the back surface 1b of the face portion 1 and a second end portion 8b connected to the back of the face portion 1 at a distance from the face portion 1. The first end portion 8a is connected to the face portion 1 in an oblong region R, and the oblong region R is surrounded by a first circle C1 with a radius of 10 mm centered on a projection point G1 where 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 is projected onto the back surface 1b, a second circle C2 with a radius of 10 mm centered on a projection point G2 where the center of gravity (not shown) of the golf club head is projected onto the back surface 1b, and two parallel line segments L1 and L2 circumscribed to the first circle C1 and the second circle C2. The first circle C1 is an imaginary circle drawn on the back surface 1b of the face portion 1 with the projection point G1 as the center. In addition, the second circle C2 is an imaginary circle drawn on the back surface 1b of the face portion 1 with the projection point G2 as the center.

[0038] The golf club head 10 is used as an iron-type golf club in a state where a shaft (not shown) is connected to the hosel 6. The iron-type golf club is one embodiment of the present disclosure.

[0039] The golf club head 10 can suppress the bending of the face 1 when hitting by having the bridge 8. Therefore, the golf club head 10 can suppress cracks and depressions in the face 1 even when the face 1 is thinned. In addition, since the second end 8b of the golf club head 10 is arranged at a distance from the face 1, the rebound performance of the face 1 can be homogenized, and the center of gravity of the golf club head as a whole can be easily deepened. That is, if the front edge of the bridge (or rib) is closely attached to the face in the entire area between the first end and the second end, the bending of the face is restricted, and the rebound performance of each part of the face is easily uneven. In contrast, the golf club head 10 can homogenize the rebound performance of the face 1 as a whole, and 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 1 and the bridge 8, the center of gravity of the bridge 8 itself is easily located behind 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.

[0040] The golf club head 10 can also achieve a lower center of gravity and a deeper center of gravity of the entire golf club head, for example. Such a golf club head is sometimes preferred in terms of its ease of operation. In this regard, according to the golf club head 10, the ease of operation can be further improved by homogenizing the rebound performance of the entire golf club head.

[0041] The golf club head 10 is mainly composed of a metal such as iron, stainless steel or an alloy. That is, the bridge portion 8 can be formed mainly of a metal such as iron, stainless steel or an alloy. It should be noted that the "main component" refers to the component with the largest content in terms of mass conversion.

[0042] (Club Face)

[0043] The face portion 1 has a front surface 1a constituting a striking surface (see Figure 5 The area within the thick frame) and the back side 1b opposite to the front side 1a (refer to Figure 6 A plurality of scoring lines 11 are provided on the front surface 1a. The plurality of scoring lines 11 extend in the toe-heel direction at intervals in the up-down direction.

[0044] As the thickness T of the face portion 1 (the plate thickness between the front surface 1a and the back surface 1b. Figure 4 ), is not particularly limited, but is preferably 1.9 mm, more preferably 1.7 mm, and further preferably 1.5 mm. Since the golf club head 10 includes the bridge portion 8, cracks and depressions in the face portion 1 can be suppressed even if the thickness T of the face portion 1 is set below the upper limit. 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 sufficient durability to the face portion 1.

[0045] (bottom)

[0046] The sole 2 extends rearward from the lower edge of the face portion 1 and is connected to the toe portion 4 at the toe side end and to the heel portion 5 at the heel side end. The sole 2 is in the shape of a thin plate having a length direction in the toe-heel direction and a width direction in the front-rear direction.

[0047] like Figures 2 to 4 As shown, the sole 2 has a groove 2a extending in the toe-heel direction. The sole 2 has the groove 2a, so that the weight of the sole 2 is reduced, and the degree of freedom of weight distribution of the entire golf club head is improved.

[0048] like Figure 3 and Figure 4 As shown, the groove 2a may be directly connected to the back surface 1b of the face portion 1. That is, the back surface 1b of the face portion 1 may also serve as the front side surface of the groove 2a. According to this structure, the weight of the sole portion 2 can be sufficiently reduced.

[0049] (Rear wall)

[0050] The rear wall portion 7 is arranged behind the face portion 1 and is separated from the face portion 1, thereby contributing to a deep center of gravity of the golf club head 10. In addition, the rear wall portion 7 is connected to the sole 2, thereby contributing to a low center of gravity of the golf club head 10. The front surface of the rear wall portion 7 also serves as the side surface of the rear side of the groove 2a. The rear wall portion 7 has a high rigidity portion 7a having a higher rigidity than other portions on the toe side in the toe-heel direction. The high rigidity portion 7a is, for example, an expanded portion in which the cross-sectional area perpendicular to the toe-heel direction is expanded.

[0051] (Bridge)

[0052] like Figure 3 and Figure 4 As shown, the bridge portion 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 portion 8 is connected to the back surface 1b of the club face 1, and the second end 8b is connected to the rear of the club face 1, and the portion between the first end 8a and the second end 8b is arranged at a distance from the club face 1. The bridge portion 8 is preferably separated from the club face 1 in the entire area between the first end 8a and the second end 8b. By configuring in this way, the deflection of the club face 1 is difficult to be constrained by the bridge portion 8, and the rebound performance of the club face 1 is easily maintained uniformly. In addition, it is easy to displace the weight of the entire golf club head to the rear, and it is easy to achieve a deep center of gravity of the golf club head 10.

[0053] like Figure 3 and Figure 4As shown in the figure, a gap 12 extending upward from the sole 2 is provided between the bridge portion 8 and the back surface 1b of the face portion 1 (more specifically, between the second portion 22 described later and the back surface 1b of the face portion 1). The gap 12 is, for example, elongated with the vertical direction as the length direction. The lower edge of the gap 12 is defined by the sole 2, and the upper edge of the gap 12 is defined by the first portion 21 described later of the bridge portion 8. The gap 12 is set to a size that the face portion 1 does not contact the bridge portion 8 when the face portion 1 is bent during impact.

[0054] like Figure 3 and Figure 4 As shown, the bridge portion 8 has a main body 13 connecting the first end 8a and the second end 8b and an expanded diameter portion 14 extending from the circumference of the first end 8a. The main body 13 can also be a plate-like portion with the direction connecting the first end 8a and the second end 8b as the length direction, the toe-heel direction as the thickness direction, and the direction perpendicular to both the length direction and the thickness direction as the width direction. The plate-like portion is, for example, a flat plate. The length of the width direction of the plate-like portion can also be greater than the length in the thickness direction. The bridge portion 8 has the plate-like portion, thereby making it easy to suppress the deflection of the club face 1 during impact. In addition, according to this structure, it is possible to suppress the weight of the bridge portion 8 from becoming too large, and it is easy to increase the freedom of weight distribution of the entire golf club head.

[0055] 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 can suppress the stress applied to the face portion 1 from being locally increased by including the enlarged diameter portion 14. As a result, cracks and depressions of the face portion 1 can be more easily suppressed.

[0056] The shape of the contact surface of the expanded diameter portion 14 that contacts the back surface 1b of the face portion 1 may be circular, polygonal, etc. Among them, a circular shape is preferred because it can promote the homogenization of the stress applied to the face portion 1. In the present disclosure, "circular" includes a perfect circle, an ellipse, an oblong, etc., among which a perfect circle is preferred.

[0057] The lower limit of the average diameter of the expanded diameter portion 14 is preferably 10 mm, more preferably 15 mm, and further preferably 17 mm from the viewpoint of achieving homogenization of 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 the thickness of the face portion 1 from being substantially thickened due to the expanded diameter portion 14. It should be noted that the “average diameter” refers to the diameter converted into a perfect circle.

[0058] The diameter of the expanded diameter portion 14 may be gradually increased toward the back surface 1b of the face portion 1. Such a shape may be, for example, a trumpet shape. By configuring the expanded diameter portion 14 in this way, it is possible to suppress the thickness of the face portion 1 from being substantially thickened due to the expanded diameter portion 14, and to easily achieve homogenization of the stress applied to the face portion 1.

[0059] As described above, the first end 8a of the bridge 8 is connected to the back surface 1b of the face portion 1 in the oval region R. More specifically, at least a portion of the first end 8a of the body 13 (a plate-shaped portion in this embodiment) is connected to the back surface 1b of the face portion 1 in the oval region R.

[0060] The first end 8a is selectively connected to the back surface 1b of the club face 1 at a position suitable for suppressing the deflection of the club face 1. To explain in more detail, in an iron-type golf club, when the club face 1 is deflected with the club and the heel 5 continuous from the club as an axis, the centroid G of the front 1a of the club face 1 can become the part of the club face 1 that is most likely to vibrate. In addition, the contact range between the front 1a of the club face 1 and the ball when hitting the ball is usually a circle with a radius of about 10mm. Therefore, the first circle C1 corresponds to the area that is most likely to vibrate when hitting the ball. In addition, for example, when the lateral moment of inertia is increased in the golf club head 10, the rigidity near the projection point G2 sometimes decreases. Therefore, the second circle C2 corresponds to the area where the club face 1 is likely to vibrate. Based on these matters, the oblong area R surrounded by the first circle C1, the second circle C2 and the two parallel line segments L1 and L2 circumscribed with the two circles C1 and C2 corresponds to the area of ​​the club face 1 that is likely to vibrate in the golf club head 10.

[0061] The first end 8a and the face portion 1 are preferably connected within a first circle C1 having a radius of 10 mm centered at a projection point G1 where the centroid G of the front face portion 1a is projected onto the back face portion 1b of the face portion 1. In addition, the projection point G1 is preferably included in the connection portion between the first end 8a and the face portion 1. By configuring in this way, the bending of the face portion 1 during hitting a ball can be easily suppressed. As a result, the thinning of the face portion 1 can be more easily achieved.

[0062] The second end portion 8b is located below the first end portion 8a. In addition, the second end portion 8b is connected to the sole 2. Thus, by connecting the second end portion 8b to the sole 2, it is easy to freely design the structure of the entire golf club head.

[0063] When the second end portion 8b is connected to the sole 2, the second end portion 8b may be connected to the rear end portion of the sole 2 (the rear end portion of the groove 2a in this embodiment). With such a configuration, it is easy to increase the front-to-back length of the bridge portion 8. As a result, the deflection of the face portion 1 when hitting a ball can be more reliably suppressed.

[0064] The second end portion 8b is connected to the rear wall portion 7. That is, in the present embodiment, the second end portion 8b is connected to both the sole 2 and the rear wall portion 7. The golf club head 10 can increase the length of the bridge portion 8 in the front-to-back direction by connecting the second end portion 8b to the rear wall portion 7, and the bridge portion 8 is supported from the rear by the rear wall portion 7. As a result, the deflection of the face portion 1 when hitting a ball can be more easily and reliably suppressed.

[0065] like Figure 2 As shown in FIG. 1 , in a rear view, the angle α formed by the imaginary line V extending in the vertical direction through the first end 8a and the central axis of the bridge portion 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 low center of gravity of the golf club head. That is, when the central axis is tilted toward the toe side relative to the imaginary line V as + and tilted toward the heel side as −, the angle α is preferably within the range of -45 degrees or more and +45 degrees or less, and more preferably within the range of -35 degrees or more and +35 degrees or less.

[0066] When viewed from behind, the second end portion 8b can be arranged on the imaginary line V or at a position closer to the toe side than the imaginary line V, and more preferably at a position closer to the toe side than the imaginary line V. That is, the angle α formed can be greater than 0 degrees and less than +45 degrees, and more preferably greater than 0 degrees and less than +45 degrees. In addition, the upper limit of the angle α formed can also be 35 degrees. By arranging the second end portion 8b at a position closer to the toe side than the imaginary line V, the golf club head 10 can connect the second end portion 8b to a portion where stress is difficult to concentrate when hitting a ball. As a result, the deflection suppression effect of the bridge portion 8 on the club face portion 1 can be further improved.

[0067] In the toe-to-heel direction when viewed from behind, the second end 8b may be disposed between both ends of the enlarged diameter portion 14. This configuration can easily prevent the bridge portion 8 from becoming too long and improve the degree of freedom in weight distribution of the entire golf club head.

[0068] like Figure 4 As shown in FIG. 1 , the bridge portion 8 includes a first portion 21 extending rearward from the first end portion 8a. In addition, the bridge portion 8 includes a second portion 22 extending upward from the second end portion 8b and connected to the first portion 21. By configuring in this way, the length of the portion extending rearward from the back surface 1b of the face portion 1 can be increased. As a result, the deflection of the face portion 1 during a ball strike can be more reliably suppressed.

[0069] The first portion 21 preferably extends in a direction perpendicular to the back surface 1b of the face portion 1. By configuring in this way, it is easy to improve the effect of suppressing the deflection of the face portion 1. It should be noted that "the first portion extends in a direction perpendicular to the back surface of the face portion" means that the angle formed by the back surface of the face portion and the central axis of the first portion is greater than 80 degrees and less than 90 degrees, preferably greater than 85 degrees and less than 90 degrees, and more preferably 90 degrees.

[0070] The rear end edge of the second portion 22 extends upward from the rear end of the bottom portion 2. By configuring in this manner, the length of the first portion 21 can be easily increased.

[0071] [Second Embodiment]

[0072] <Iron-type golf club heads>

[0073] Figure 7 The iron-type golf club head 30 (hereinafter, also referred to as the "golf club head 30") has Figures 1 to 4 The golf club head 10 is a golf club head 10 and a cover 40 that closes the rear opening (an opening defined by the top 3, the toe 4, the heel 5, and the inner periphery of the rear wall 7) of the golf club head 10. 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 cover 40. The cover 40 has a cutout 41 for exposing the bridge 8.

[0074] In the golf club head 30, the bridge portion 8 is exposed from the cover portion 40, so that the length of the bridge portion 8 in the front-rear direction is increased. Therefore, the golf club head 30 can easily and reliably suppress the deflection of the face portion 1 when hitting a ball.

[0075] [Other embodiments]

[0076] The above embodiments do not limit the structure of the present invention. Therefore, the above embodiments can omit, replace or add the constituent elements of each part of the above embodiments based on the description of this specification and technical common sense, and all of them should be interpreted as belonging to the scope of the present invention.

[0077] From the viewpoint of increasing the degree of freedom of weight distribution of the entire golf club head, the golf club head preferably has only a single bridge portion. In addition, preferably, no components other than the bridge portion (such as ribs, etc.) are arranged on the back of the face portion. However, other components may be arranged on the back of the face portion within the range in which the desired quality can be maintained in an iron-type golf club head.

[0078] From the viewpoint of promoting the lower center of gravity of the golf club head as a whole, the angle formed by the imaginary line V and the central axis of the bridge portion is preferably less than 45 degrees. However, by thinning the wall of the face portion of the golf club head, the degree of freedom of weight distribution of the golf club head as a whole can be increased. Therefore, the angle formed can be set according to the quality required of the golf club head.

[0079] Preferably, the bridge portion is designed not to restrict the deflection of the face portion. However, the present disclosure does not intend to exclude a structure in which a portion between the first end and the second end of the bridge portion contacts the back surface of the face portion.

[0080] In the above embodiment, the second end portion is described as being connected to both the bottom portion and the rear wall portion. However, the second end portion may be connected to only the bottom portion or only the rear wall portion. In addition, if the quality required for the golf club head can be satisfied, the second end portion may be connected to either the toe portion or the heel portion.

[0081] The shape of the main body of the bridge portion is not limited to the plate-shaped portion. For example, the main body may be in the shape of a round rod. In addition, when the main body is a plate-shaped portion, the length in the width direction of the plate-shaped portion may be less than the length in the thickness direction.

[0082] The bridge portion may also be a shape that does not have either or both of the first portion and the second portion. For example, the bridge portion may be provided in a manner that linearly connects the back surface of the face portion to the rear wall portion. In addition, another portion may be provided between the first portion and the second portion.

[0083] The bridge portion may be configured not to have the enlarged diameter portion as long as cracks or depressions in the face portion can be suppressed.

[0084] The specific structure of the bottom is not limited to the structure described in the above embodiment. For example, the bottom may not have a groove extending in the toe-heel direction. In addition, even if the bottom has a groove, the groove may be formed at a position away from the back of the face portion, for example.

[0085] [Example]

[0086] Hereinafter, the present disclosure will be described in detail based on examples, but the present disclosure is not to be construed as being limited to the description of the examples.

[0087] (Iron golf club head)

[0088] Iron-type golf club heads No. 1 and No. 2 were prepared. The golf club head No. 2 did not have a bridge portion on the back of the face portion. The golf club head No. 1 had the same structure as the golf club head No. 2 except that it had a bridge portion on the back of the face portion. As the bridge portion of the golf club head No. 1, Figures 1 to 4 The first end of the bridge portion is arranged at a projection point where the centroid of the front of the club face is projected onto the back of the club face. The bridge portion has an expanded diameter portion around the first end. The contact surface between the expanded diameter portion and the back of the club face is a perfect circle. In addition, the diameter of the expanded diameter portion is 20 mm.

[0089] (Durability test)

[0090] A predetermined number of golf balls were directly hit on the golf club heads No. 1 and No. 2. As a result, even when the thickness of the face portion of the golf club head No. 1 was set to 1.3 mm, no cracks or depressions were generated on the face portion. On the other hand, when the thickness of the face portion of the golf club head No. 2 was less than 2.0 mm, cracks and depressions were generated on the face portion. The results of the durability test are shown in Table 1.

[0091]

Table 1

[0092]

[0093] As shown in Table 1, the golf club head No. 1 having a bridge portion can reduce the thickness of the face portion by 0.7 mm compared to the golf club head No. 2. As a result, the weight of the golf club head can be reduced by 10.3 g. It can be seen that by providing a bridge portion on the back of the face portion, both the thinning of the face portion and the control of the center of gravity of the golf club head can be achieved.

[0094] Description of Reference Numerals

[0095] 1: Club face

[0096] 1a: Front

[0097] 1b: Back side

[0098] 2: Bottom

[0099] 2a: Slot

[0100] 3: Top

[0101] 4: Toe

[0102] 5: Heel

[0103] 6: The neck

[0104] 7: Rear wall

[0105] 7a: High rigidity part

[0106] 8: Bridge

[0107] 8a: First end

[0108] 8b: Second end

[0109] 10, 30: Iron-type golf club heads

[0110] 11: Score line

[0111] 12: Gap

[0112] 13: Main body

[0113] 14: Expansion section

[0114] 21: Part 1

[0115] 22: Part 2

[0116] 40: cover

[0117] 41: Incision

[0118] C1: First circle

[0119] C2: Second circle

[0120] G: The centroid of the front of the club face

[0121] G1: Project the centroid of the front of the club face to the projection point on the back

[0122] G2: The projection point of the center of gravity of the golf club head onto the back of the club face

[0123] L1, L2: Line segments circumscribed to the first and second circles

[0124] R: oblong area

[0125] T: Thickness of the face

[0126] V: an imaginary line passing through the first end and extending in the vertical direction

[0127] α: An angle formed between an imaginary line passing through the first end portion and extending in the vertical direction and the central axis of the bridge portion.

Claims

1. An iron-type golf club head, comprising a club face portion and a sole portion extending rearward from a lower edge of the club face portion, A bridge portion is provided, the bridge portion having a first end portion connected to the back surface of the face portion and a second end portion connected to the face portion at a distance from the face portion and behind the face portion, The first end portion and the club face portion are connected in an oblong area, and the oblong area is surrounded by a first circle with a radius of 10 mm centered on a projection point where the centroid of the back side of the club face portion or the centroid of the front side of the club face portion is projected onto the back side, a second circle with a radius of 10 mm centered on a projection point where the center of gravity of the golf club head is projected onto the back side, and two parallel line segments circumscribed to the first circle and the second circle.

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

3. The iron-type golf club head according to claim 1 or 2, The second end portion is located below the first end portion. In a rear view, an angle formed by an imaginary line extending in a vertical direction and passing through the first end portion and a central axis of the bridge portion is 45 degrees or less.

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

5. The iron-type golf club head according to claim 1 or 2, The bridge portion is separated from the face portion over the entire region between the first end portion and the second end portion.

6. The iron-type golf club head according to claim 1 or 2, The second end is connected to the bottom.

7. The iron-type golf club head according to claim 1 or 2, A rear wall portion is provided, the rear wall portion being separated from the face portion and protruding upward from a rear end portion of the sole portion, The second end portion is connected to the rear wall portion.

8. The iron-type golf club head according to claim 1 or 2, The bridge portion includes a plate-shaped portion, wherein the plate-shaped portion has a direction connecting the first end portion and the second end portion as a length direction, a toe-to-heel direction as a thickness direction, and a direction perpendicular to both the length direction and the thickness direction as a width direction. The length of the plate-shaped portion in the width direction is greater than the length in the thickness direction.

9. The iron-type golf club head according to claim 1 or 2, The bridge portion includes a first portion extending rearward from the first end portion and a second portion extending upward from the second end portion and connected to the first portion.

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

11. The iron-type golf club head according to claim 1 or 2, The bridge portion includes an enlarged diameter portion that is provided around the first end portion so as to increase the diameter of the first end portion and is connected to the back surface of the face portion.

12. The iron-type golf club head according to claim 11, The contact surface between the enlarged diameter portion and the back surface of the face portion is circular.

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