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, the easier it is to lift the ball, and the deeper the center of gravity of the club head, the better the tolerance. Therefore, the lower and deeper the center of gravity of the club head, the easier it is to operate the iron.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-65468 Utility Model Content

[0006] Technical problems to be solved by the utility model

[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 thinning the face portion of an iron-type golf club head reduces the rigidity of the face portion, resulting in a poorer feel at impact. Patent Document 1 states that thinning the face portion and improving the feel at impact can be achieved by providing a rib connected to the sole and disposed on the back of the face portion.

[0009] However, from the viewpoint of reducing the thickness of the face portion and controlling the operability 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 the above 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 operation of the golf club head.

[0011] Technical solutions to 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 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 having a radius of 10 mm centered at a projection point of the back of the club face portion or the centroid of the front of the club face portion projected onto the back, a second circle having a radius of 10 mm centered at a projection point of the center of gravity of the golf club head projected onto the back, and two parallel line segments circumscribing the first circle and the second circle.

[0013] (2) In (1), 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 imaginary line passing through the first end portion and extending in the vertical direction forms an angle of less than 45 degrees with the central axis of the bridging portion.

[0015] (4) In (3) above, the second end portion may be arranged on the toe side of the imaginary line when viewed from behind.

[0016] (5) In any one of (1) to (4) above, 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 (1) to (5) above, 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 bulges upward from the 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 connecting the first end portion and the second end portion, a thickness direction in the toe-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 (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 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.

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

[0024] It should be noted that in this disclosure, "front" refers to the side where 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 surface of the club face” refers to the flat surface opposite to the front surface of the club face (see the area within the thick frame). Figure 6 The area surrounded by the thick solid line and the thick dotted line). In addition, the "flat surface" includes a shape with a concave and 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" refers to the projection point of the center of gravity of the golf club head in the normal direction of the front of the club face relative to the back of the club face. The "rear view" refers to the rear view of the iron-type golf club head in a state where it is arranged on a horizontal plane in a manner to have a prescribed elevation angle and loft angle (the inherent elevation angle and loft angle prescribed in the iron-type golf club head). The "toe-heel direction" refers to the horizontal direction orthogonal to the front-to-back direction in a state where the iron-type golf club head is arranged on a horizontal plane in a manner to have a prescribed elevation angle and loft angle. The "rear end edge of the second part extends upward from the rear end portion of the sole" includes: a structure in which the rear end edge of the second part extends directly from the rear end portion of the sole; and a structure in which the rear wall portion bulges from the rear end portion of the sole, and the rear end edge of the second part extends from the rear wall portion.

[0025] Beneficial effects

[0026] The iron-type golf club head disclosed herein, in one aspect, comprises the bridge portion, which suppresses deflection of the face portion during impact. Consequently, even when the face portion is thinned, cracks and dents can be suppressed. Furthermore, the second end portion of the iron-type golf club head is spaced apart from the face portion, thereby achieving uniform rebound performance across the face portion and facilitating a deeper center of gravity for the entire golf club head. Consequently, the iron-type golf club head can control the thinning of the face portion and improve 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 one 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 It is from Figure 1 A 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 taken along line IV-IV.

[0031] Figure 5 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 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 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 the actual dimensions, ratios, etc. In the present disclosure, the records of "first" and "second" are used to distinguish the constituent elements assigned "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 The iron-type golf club head 10 (hereinafter also referred to as the "golf club head 10") includes a club face 1 and a sole 2 extending rearward from the lower edge of the club face 1. In addition, the golf club head 10 includes: a top 3 extending rearward from the upper edge of the club face 1; a toe 4 extending rearward from the toe side (front end side) of the club face 1; a heel 5 provided on the heel side (opposite side of the front end side) of the club face 1; and a hosel 6 provided continuously with the heel 5. Furthermore, the golf club head 10 includes a rear wall 7 separated from the club face 1 and bulging upward from the rear end portion of the sole 2. Figure 3 and Figure 4 As shown, the golf club head 10 includes a bridge portion 8 having a first end 8a connected to the back surface 1b of the face portion 1 and a second end 8b spaced apart from the face portion 1 and connected to the rear of the face portion 1. The first end 8a and the face portion 1 are connected in an oblong region R. This oblong region R is surrounded by a first circle C1 with a radius of 10 mm centered at a projection point G1, which is the centroid of the back surface 1b of the face portion 1 (not shown) or the centroid G of the front surface 1a of the face portion 1, projected onto the back surface 1b; a second circle C2 with a radius of 10 mm centered at a projection point G2, which is the center of gravity of the golf club head (not shown) projected onto the back surface 1b; and two parallel line segments L1 and L2 circumscribing the first and second circles C1 and 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 its center. Furthermore, 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 its 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. This iron-type golf club is one embodiment of the present disclosure.

[0039] The golf club head 10, by including the bridge portion 8, can suppress deflection of the face portion 1 during impact. Therefore, even with a thinner face portion 1, cracks and dents can be suppressed. Furthermore, because the second end portion 8b of the golf club head 10 is spaced apart from the face portion 1, the rebound performance of the face portion 1 is homogenized, and the center of gravity of the entire golf club head is easily increased. Specifically, if the front edge of the bridge portion (or rib) is in close contact with the face portion across the entire area between the first and second ends, deflection of the face portion is limited, and the rebound performance of each part of the face portion tends to become uneven. In contrast, the golf club head 10 can achieve homogenized rebound performance across the entire face portion 1, making it easier to handle. Furthermore, because the golf club head 10 has a gap between the face portion 1 and the bridge portion 8, the center of gravity of the bridge portion 8 itself tends to be 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 operation of the golf club head.

[0040] For example, the golf club head 10 can also achieve a lower and deeper center of gravity for the entire golf club head. Such a golf club head is sometimes preferred for ease of operation. In this regard, the golf club head 10 can further improve ease of operation 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.

[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 scored lines 11 are provided on the front face 1a. The plurality of scored lines 11 extend in the toe-heel direction at intervals in the vertical direction.

[0044] As the thickness T of the face portion 1 (the plate thickness between the front face 1a and the back face 1b. Figure 4 The upper limit of the thickness T is not particularly limited, but is preferably 1.9 mm, more preferably 1.7 mm, and even more preferably 1.5 mm. Because the golf club head 10 includes the bridge portion 8, cracks and dents 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, for example, to 1.0 mm to ensure sufficient durability of the face portion 1.

[0045] (bottom)

[0046] The sole 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 2 is in the shape of a thin plate having a length in the toe-heel direction and a width in the front-back 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, thereby reducing the weight of the sole 2 and improving the freedom of weight distribution of the entire golf club head.

[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. With this structure, the weight of the sole portion 2 can be sufficiently reduced.

[0049] (Rear wall)

[0050] The rear wall portion 7 is disposed behind the face portion 1, separately from the face portion 1, thereby contributing to a lower center of gravity for the golf club head 10. Furthermore, the rear wall portion 7 is connected to the sole portion 2, thereby contributing to a lower center of gravity for 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-to-heel direction, which is more rigid than the other portions. The high-rigidity portion 7a is, for example, an expanded portion having an expanded cross-sectional area perpendicular to the toe-to-heel direction.

[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. The portion between the first end 8a and the second end 8b is spaced apart 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. With this structure, the deflection of the club face 1 is less likely to be constrained by the bridge portion 8, making it easier to maintain the rebound performance of the club face 1 uniformly. In addition, it is easier to shift the weight of the entire golf club head rearward, making it easier to achieve a deep center of gravity for the golf club head 10.

[0053] like Figure 3 and Figure 4As shown, 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 its length in the vertical 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 sized so that the face portion 1 and the bridge portion 8 do not contact each other when the face portion 1 flexes during impact.

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

[0055] The expanded diameter portion 14 is provided around the first end portion 8a to increase the diameter of the first end portion 8a and is connected to the back surface 1b of the face portion 1. The expanded diameter portion 14 in the golf club head 10 can prevent localized increases in stress applied to the face portion 1. As a result, cracks and dents in 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 can be circular or polygonal. A circular shape is preferred because it promotes uniformity of stress applied to the face portion 1. In this disclosure, the term "circular" includes a perfect circle, an ellipse, an oblong, and the like, with a perfect circle being preferred.

[0057] The lower limit of the average diameter of the expanded diameter portion 14 is preferably 10 mm, more preferably 15 mm, and even more preferably 17 mm, from the perspective of achieving uniform stress applied to the face portion 1. On the other hand, the upper limit of the average diameter is preferably 30 mm, and more preferably 25 mm, from the perspective of preventing the face portion 1 from substantially increasing in thickness due to the expanded diameter portion 14. It should be noted that the "average diameter" refers to the diameter converted to a perfect circle.

[0058] The diameter of the expanded diameter portion 14 may also gradually increase toward the back surface 1b of the face portion 1. Such a shape may be, for example, a trumpet shape. This configuration of the expanded diameter portion 14 can prevent the face portion 1 from substantially increasing in thickness due to the expanded diameter portion 14 and facilitates uniformity of stress applied to the face portion 1.

[0059] As described above, the first end 8a of the bridge portion 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 face 1 at a position suitable for suppressing deflection of the face 1. To explain in more detail, in an iron-type golf club, when the face 1 deflects about the club and the heel 5 extending therefrom, the centroid G of the front face 1a of the face 1 can be the portion of the face 1 most susceptible to vibration. Furthermore, the area of contact between the front face 1a of the face 1 and the ball during impact is typically a circle with a radius of approximately 10 mm. Therefore, the first circle C1 corresponds to the area most susceptible to vibration during impact. Furthermore, for example, if the lateral moment of inertia is increased in this golf club head 10, the rigidity near the projection point G2 may decrease. Therefore, the second circle C2 corresponds to the area of the face 1 most susceptible to vibration. Based on these considerations, the oblong area R enclosed by the first circle C1, the second circle C2, and the two parallel line segments L1 and L2 circumscribing these circles C1 and C2 corresponds to the area of the face 1 most susceptible to vibration in this golf club head 10.

[0061] The first end portion 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, which is the centroid G of the front face portion 1a of the face portion 1 projected onto the back face portion 1b of the face portion 1. Furthermore, the connection between the first end portion 8a and the face portion 1 preferably includes the projection point G1. This configuration can easily suppress deflection of the face portion 1 during impact. Consequently, 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 also be connected to the rear end portion of the sole 2 (in this embodiment, the rear end portion of the groove 2a). This configuration facilitates increasing the front-to-back length of the bridge portion 8. As a result, deflection of the face portion 1 during impact can be more reliably suppressed.

[0064] The second end portion 8b is connected to the rear wall portion 7. That is, in this embodiment, the second end portion 8b is connected to both the sole portion 2 and the rear wall portion 7. With the second end portion 8b connected to the rear wall portion 7, the golf club head 10 can increase the front-to-back length of the bridge portion 8, while also supporting the bridge portion 8 from behind via the rear wall portion 7. As a result, deflection of the face portion 1 during impact can be more easily and reliably suppressed.

[0065] like Figure 2 As shown, in a rear view, the angle α formed between an imaginary line V extending vertically through the first end portion 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 perspective of promoting a low center of gravity for the golf club head. Specifically, assuming that the central axis is tilted to the toe with respect to the imaginary line V as + and tilted to the heel with respect to the imaginary line V as -, the angle α is preferably within the range of -45 degrees to +45 degrees, and more preferably within the range of -35 degrees to +35 degrees.

[0066] In rearview, the second end portion 8b can be positioned on the imaginary line V or toe-side relative to the imaginary line V, more preferably toe-side relative to the imaginary line V. That is, the angle α formed can be between 0 degrees and +45 degrees, more preferably between 0 degrees and +45 degrees. Furthermore, the upper limit of the angle α can be 35 degrees. By positioning the second end portion 8b toe-side relative to the imaginary line V, the golf club head 10 can be connected to a portion where stress is less likely to concentrate during impact. As a result, the bridge portion 8 can further enhance its ability to suppress deflection of the face portion 1.

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

[0068] like Figure 4 As shown, the bridge portion 8 includes a first portion 21 extending rearward from the first end portion 8a. Furthermore, the bridge portion 8 includes a second portion 22 extending upward from the second end portion 8b and connected to the first portion 21. This configuration increases the length of the portion extending rearward from the back surface 1b of the face portion 1. As a result, deflection of the face portion 1 during impact can be more reliably suppressed.

[0069] The first portion 21 preferably extends perpendicularly to the back surface 1b of the face portion 1. This configuration enhances the effect of suppressing deflection of the face portion 1. It should be noted that "the first portion extends perpendicularly to the back surface of the face portion" means that the angle formed between the back surface of the face portion and the central axis of the first portion is greater than or equal to 80 degrees and less than or equal to 90 degrees, preferably greater than or equal to 85 degrees and less than or equal to 90 degrees, and more preferably 90 degrees.

[0070] The rear end edge of the second portion 22 extends upward from the rear end portion 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 "golf club head 30") has Figures 1 to 4 The golf club head 10 is provided with a cover 40 that closes the rear opening of the golf club head 10 (the opening defined by the crown 3, toe 4, heel 5, and the inner periphery of the rear wall 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 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, thereby increasing the length of the bridge portion 8 in the front-rear direction. 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 components 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 perspective of increasing the degree of freedom in weight distribution throughout the golf club head, the golf club head preferably includes only a single bridge portion. Furthermore, preferably, no components other than the bridge portion (e.g., ribs) are disposed on the back of the face portion. However, other components may be disposed on the back of the face portion within the range that maintains the desired quality of an iron-type golf club head.

[0078] To lower the 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 45 degrees or less. However, by thinning the face portion of the golf club head, the degree of flexibility in overall weight distribution can be increased. Therefore, the angle can be set based on the required quality 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 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, if the required quality of the golf club head is met, 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 of the plate-shaped portion in the width direction may be less than the length in the thickness direction.

[0082] The bridge portion may also have a shape that does not include either or both of the first and second portions. For example, the bridge portion may be provided so as to linearly connect the back surface of the face portion to the rear wall portion. Alternatively, another portion may be provided between the first and second portions.

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

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

[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 these Examples.

[0087] (Iron-type golf club head)

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

[0089] (Durability test)

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

[0091]

Table 1

[0092]

[0093] As shown in Table 1, golf club head No. 1, which includes a bridge portion, can reduce the thickness of the face portion by 0.7 mm compared to golf club head No. 2. Consequently, the weight of the golf club head can be reduced by 10.3 g. This demonstrates that providing a bridge portion on the back of the face portion allows for both thinning the face portion and controlling the center of gravity of the golf club head.

[0094] Description of Reference Numerals

[0095] 1: Club face

[0096] 1a: Front

[0097] 1b: Back

[0098] 2: Bottom

[0099] 2a: Slot

[0100] 3: Top

[0101] 4: Toe

[0102] 5: Heel

[0103] 6: The hosel

[0104] 7: Posterior wall

[0105] 7a: High rigidity part

[0106] 8: Bridging part

[0107] 8a: First end

[0108] 8b: Second end

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

[0110] 11: Scribe Line

[0111] 12: Gap

[0112] 13: Main body

[0113] 14: Expanded diameter

[0114] 21: Part 1

[0115] 22: Part 2

[0116] 40: cover

[0117] 41: Incision

[0118] C1: First circle

[0119] C2: Second circle

[0120] G: Centroid of the front of the clubface

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

[0122] G2: The point where the center of gravity of the golf club head is projected 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 face portion and a sole portion extending rearward from a lower edge of the face portion, wherein: 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 therefrom 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 of the centroid of the back surface of the club face portion or the centroid of the front surface of the club face portion onto the back surface, a second circle with a radius of 10 mm centered on a projection point of the center of gravity of the golf club head onto the back surface, 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, wherein: The first end portion and the face portion are connected within a first circle with 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, wherein: The second end portion is located below the first end portion. In a rear view, an angle formed between 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, wherein: 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, wherein: 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, wherein: The second end portion is connected to the bottom portion.

7. The iron-type golf club head according to claim 1 or 2, wherein: A rear wall portion is provided, the rear wall portion being separated from the face portion and bulging upward from the 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, wherein: The bridge portion includes a plate-shaped portion having a length 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. 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, wherein: 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, wherein: 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, wherein: The bridge portion includes an expanded 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, wherein: The contact surface between the enlarged diameter portion and the rear surface of the face portion is circular.

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