Golf club and weight member for golf club

Abstract

To provide a golf club, etc. including a weight member stably held inside a shaft without sacrificing productivity.SOLUTION: A golf club comprises a pipe-like shaft 2 including a first end 2a with a first inside diameter D1, a second end opposite thereto and a hollow part i in the inside thereof, and a weight member 5 mounted on the first end 2a side of the shaft 2. The weight member 5 includes an insertion part 51 disposed in the hollow part i, an engagement part 52 being engaged with the first end 2a at the outside of the shaft 2, and a plurality of projections 53 projecting from the insertion part 51 in the shaft radial direction. Each of the projections 53 includes a tapered portion 6, where the projection height t from the insertion part 51 in the shaft radial direction decreases toward the second end side. The height Lt of the tapered portion 6 along a shaft axis direction is larger than 50% of the maximum length L of the projections 53 along the shaft axis direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a golf club and a weight member for a golf club.

Background Art

[0002] The club balance of a golf club affects the swing. A club balance suitable for a golfer varies depending on the golfer's strength and the like. To adjust the club balance, a golf club with a weight member attached to one end side of the shaft has been proposed, for example, in Patent Document 1 below.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When industrially producing a golf club as described above, in order to attach the weight member to the hollow portion of the shaft, the outer diameter of the weight member needs to be formed with high precision so as to match the inner diameter of the shaft. On the other hand, such a weight member makes it difficult to insert into the shaft, which may deteriorate productivity. Further, the weight member needs to be stably held inside the shaft even when receiving an impact force during ball striking.

[0005] The present disclosure has been devised in view of the above circumstances, and the main object thereof is to provide a golf club or the like in which a weight member is stably held inside a shaft without deteriorating productivity.

Means for Solving the Problems

[0006] The present disclosure relates to a golf club including a pipe-shaped shaft having a first end with a first inner diameter D1 and a second end on the opposite side thereof and having a hollow portion inside, and a weight member attached to the side of the first end of the shaft. The weight member includes an insertion portion disposed in the hollow portion, an engagement portion that engages with the first end outside the shaft, and a plurality of protrusions protruding in the shaft radius direction from the insertion portion. Each of the protrusions is made of an elastically deformable material. In a state before the weight member is attached to the shaft, an outer diameter D2 of the insertion portion is smaller than the first inner diameter D1 of the shaft, and a maximum outer diameter D3 of the insertion portion including the protrusions is larger than the first inner diameter D1. Each of the protrusions includes a tapered portion in which a protruding height in the shaft radius direction from the insertion portion decreases toward the second end side, and a length Lt of the tapered portion along the shaft axis direction is larger than 50% of a maximum length L of the protrusion along the shaft axis direction. In a state after the weight member is attached to the shaft, at least a part of each of the plurality of protrusions is in contact with an inner peripheral surface of the shaft in a state of being elastically compressed and deformed.

Advantages of the Invention

[0007] By adopting the above configuration, the golf club of the present disclosure can stably hold the weight member inside the shaft without deteriorating productivity. Further, by adopting the above configuration, the weight member for the golf club of the present disclosure can be stably held inside the shaft without impairing the productivity of the golf club.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. This specification is not intended to limit the present disclosure in any way. Also, each embodiment can be used alone or in various combinations. Further, throughout this specification, the same or common elements are given the same reference numerals, and duplicate descriptions are omitted.

[0010] FIG. 1 is a perspective view of a golf club 1 showing an embodiment of the present disclosure. As shown in FIG. 1, the golf club 1 includes, for example, a shaft 2, a golf club head 3, a grip 4, and a weight member 5.

[0011] [Shaft] FIG. 2 shows a cross-sectional view (a cross-sectional view including the shaft axis center line) on the grip 4 side of FIG. 1. As shown in FIGS. 1 and 2, the shaft 2 is formed in a pipe shape having a hollow portion i inside. More specifically, in a cross-section orthogonal to the shaft axis direction, both the outer peripheral surface 2o and the inner peripheral surface 2i of the shaft 2 are circular. Therefore, the shaft 2 has a cylindrical shape. The shaft 2 of the present embodiment is formed of, for example, a fiber-reinforced resin. In other embodiments, the shaft 2 may be a metal material.

[0012] The shaft 2 has a first end 2a and a second end 2b on the opposite side in the shaft axis direction. The first end 2a of the shaft 2 has a first inner diameter D1. In this embodiment, the first inner diameter D1 of the shaft 2 is, for example, about 12 to 16 mm. The shaft 2 may be configured with a constant outer diameter and inner diameter. In this embodiment, the first end 2a of the shaft 2 has an outer diameter and an inner diameter larger than those of the second end 2b.

[0013] [Golf club head] As shown in FIG. 1, the golf club head 3 is for hitting a ball. In this embodiment, the golf club head 3 is fixed to the second end 2b of the shaft 2. The golf club head 3 is configured as, for example, a wood type. In other embodiments, the golf club head 3 may be an iron type, a hybrid type or a putter type.

[0014] [Grip] As shown in FIG. 1, in this embodiment, the grip 4 is fixed to the first end 2a side of the shaft 2. As shown in FIG. 2, the grip 4 includes, for example, a cylindrical grip portion 4a which is the portion where the golfer holds, and a rear end portion 4b provided on one end side of the grip portion 4a.

[0015] The grip portion 4a has a substantially cylindrical shape and is, for example, tapered so as to taper off as it moves away from the rear end portion 4b. Also, the other end side of the grip portion 4a is an opening into which the shaft 2 can be inserted.

[0016] The rear end portion 4b covers the first end 2a of the shaft 2. The rear end portion 4b is provided with, for example, a through hole 4c for venting air when the shaft 2 is inserted.

[0017] [Weight member] As shown in FIGS. 1 and 2, the weight member 5 of the present embodiment is attached to the side of the first end 2a of the shaft 2. For example, the weight member 5 of the present embodiment is provided on the side opposite to the golf club head 3 of the shaft 2. Such a weight member 5 helps to provide, for example, a counterbalanced golf club 1. Note that, with respect to the weight member 5, the side of the first end 2a of the shaft 2 may be referred to as the "rear end side", and the side of the second end 2b of the shaft 2 may be referred to as the "front end side".

[0018] The weight member 5 of the present embodiment includes an insertion portion 51 disposed in the hollow portion i of the shaft 2, an engagement portion 52 that engages with the first end 2a outside the shaft 2, and a plurality of protrusions 53 that locally protrude radially from the shaft from the insertion portion 51.

[0019] [Insertion portion] FIG. 3 shows a side view of the state before the weight member 5 is attached to the shaft 2. FIG. 4 is a side view in which the shaft 2 and the weight member 5 are separated with their centers aligned. Further, FIG. 5 is a cross-sectional view taken along line V-V of FIG. 4.

[0020] As shown in FIGS. 3 to 5, the insertion portion 51 is, for example, a heavy object having a length in the shaft axis direction. The insertion portion 51 of the present embodiment is formed in a cylindrical shape. In other embodiments, the insertion portion 51 may be cylindrical or prismatic. Although not particularly limited, the total weight of the weight member 5 is preferably about 1 to 100 g, for example.

[0021] In the state before the weight member 5 is attached to the shaft 2, the outer diameter D2 (FIG. 4) of the insertion portion 51 (excluding the protrusions 53) is formed smaller than the first inner diameter D1 of the first end 2a of the shaft 2. The outer diameter D2 of the insertion portion 51 may be constant or may vary in the shaft axis direction. When the outer diameter of the insertion portion 51 varies, the outer diameter D2 means the maximum outer diameter.

[0022] [Engagement portion] The engaging portion 52 is formed, for example, to protrude outward in the shaft radial direction on the rear end side of the insertion portion 51. As shown in FIG. 4, the engaging portion 52 of the present embodiment is formed in a flange shape having an outer diameter D5. The outer diameter D5 of the engaging portion 52 is larger than the first inner diameter D1 of the first end 2a of the shaft 2. Therefore, as shown in FIG. 2, the engaging portion 52 engages with the end face of the first end 2a outside the shaft 2 and is located outside the shaft 2. In a preferred embodiment, the engaging portion 52 is sandwiched and held between the rear end portion 4b of the grip 4 and the end face of the first end 2a of the shaft 2. In other embodiments, the engaging portion 52 may be a plurality of protruding pieces that protrude outward in the shaft radial direction from the insertion portion 51.

[0023] [Projection] In the present embodiment, the plurality of protrusions 53 are formed at positions on the engaging portion 52 side rather than the tip of the insertion portion 51 in the shaft axial direction. Further, the protrusions 53 are formed at a position separated from the engaging portion 52 by a distance Y in the shaft axial direction. As shown in FIG. 5, it is desirable that the plurality of protrusions 53 are arranged at equal intervals in the shaft circumferential direction.

[0024] Each of the plurality of protrusions 53 is made of an elastically deformable material. In a preferred embodiment, the protrusion 53 is formed of a rubber-like elastic body. The rubber-like elastic body is a material having rubber elasticity, and includes, in addition to vulcanized rubber, an elastomer made of a resin-based material. The protrusion 53 of the present embodiment is formed of, for example, vulcanized rubber. In the present embodiment, not only the protrusion 53 but also the insertion portion 51 and the engaging portion 52 are formed of a rubber-like elastic body. Although not shown, a metal material or the like may be combined inside the insertion portion 51 in order to provide a larger weight.

[0025] As shown in FIG. 4, in the state before the weight member 5 is attached to the shaft 2, the maximum outer diameter D3 of the insertion portion 51 including the plurality of protrusions 53 is formed larger than the first inner diameter D1 of the first end 2a of the shaft 2. Here, the "maximum outer diameter D3 of the insertion portion 51 including the plurality of protrusions 53" is equal to twice the distance from the axial center of the insertion portion 51 to the outermost position of the protrusion 53 in the shaft radial direction.

[0026] As shown in FIGS. 3 and 4, in the state before the attachment of the weight member 5 to the shaft 2, each of the protrusions 53 includes a tapered portion 6. In the tapered portion 6, the protruding height t in the radial direction of the shaft from the insertion portion 51 decreases toward the second end 2b side of the shaft 2. Further, in the weight member 5 of the present embodiment, the length Lt of the tapered portion 6 along the shaft axis direction is formed to be larger than 50% of the maximum length L of the protrusion 53 along the shaft axis direction, preferably 95% or more of the maximum length L, more preferably substantially 100% of the maximum length L.

[0027] [Operation of the weight member of the present embodiment] In the weight member 5 configured as described above, since the outer diameter D2 of the insertion portion 51 is formed to be smaller than the first inner diameter D1 of the shaft, the insertion portion 51 can be easily inserted into the hollow portion i of the shaft 2 from the first end 2a side of the shaft 2. This helps to streamline the operation process of inserting the weight member 5 into the hollow portion i of the shaft 2 and improve the productivity of the golf club 1. Although not particularly limited, in order to enhance such an effect, it is desirable that the outer diameter D2 of the insertion portion 51 is formed to be about 0.10 to 0.15 mm smaller than the first inner diameter D1 of the first end 2a of the shaft 2.

[0028] When the insertion portion 51 of the weight member 5 is further inserted into the hollow portion i of the shaft 2, the engaging portion 52 engages with the first end 2a outside the shaft 2, and the insertion position of the weight member 5 is determined. Thereby, it becomes possible to always attach the weight member 5 to the shaft 2 at a fixed position. This helps to keep the balance of the golf club 1 constant.

[0029] Further, for the weight member 5, the maximum outer diameter D3 of the insertion portion 51 including the protrusions 53 is formed to be larger than the first inner diameter D1 of the shaft 2. Therefore, as shown in FIG. 2, in the state after the weight member 5 is attached to the shaft 2, at least a part of each of the plurality of protrusions 53 is in contact with the inner peripheral surface 2i of the shaft 2 in a state of being elastically deformed by compression. Accordingly, due to the frictional force and the vertical resistance force between the protrusions 53 and the inner peripheral surface 2i of the shaft 2, the weight member 5 can be stably held in the shaft circumferential direction, the shaft axial direction, and the shaft radial direction.

[0030] Furthermore, for the protrusions 53 of the present embodiment, the length Lt of the tapered portion 6 is formed to be larger than 50% of the maximum length L of the protrusions 53. For this reason, the weight member 5 of the present embodiment can have each protrusion 53 contact the inner peripheral surface 2i of the shaft 2 over a wider range without deteriorating the workability of inserting the weight member 5 into the shaft 2, and thus, a large holding force can be generated. In addition, the shape of the protrusions 53 of the present embodiment can position the center of gravity of each individual protrusion 53 on the first end 2a side of the weight member 5 as a relative one. This can position the center of gravity of the weight member 5 on the first end 2a side of the shaft 2, and thus, the counterbalance effect of the golf club 1 can be enhanced.

[0031] [Preferred Embodiment] FIG. 6 shows a side view of the protrusions 53 as viewed from the tangential direction in the shaft circumferential direction. In the state before the weight member 5 is attached to the shaft 2, it is desirable that the centroid Z of the protrusion side shape of the protrusions 53 as viewed from the tangential direction in the shaft circumferential direction is positioned on the first end 2a side of the shaft 2 rather than at the central position of the maximum length L along the shaft axial direction of the protrusions 53. Thereby, the center of gravity of the weight member 5 can be more reliably positioned on the first end 2a side of the shaft 2, and thus, the counterbalance effect of the golf club 1 can be further enhanced.

[0032] The distance Y in the shaft axis direction between the protrusion 53 and the engaging portion 52 is, for example, 1 mm or more, more preferably 2 mm or more. When the protrusion 53 is separated from the engaging portion 52, a space is formed between the two, enabling elastic deformation of the protrusion 53 using this space. Therefore, in such a manner, the weight member 5 can be inserted into the shaft 2 up to the position where the engaging portion 52 abuts against the end face of the first end 2a of the shaft 2.

[0033] As shown in FIG. 6, the protrusion 53 of the present embodiment includes a first surface 5a facing the inner peripheral surface 2i of the shaft 2. In the present embodiment, the entire first surface 5a is a surface inclined with respect to the shaft axis direction so as to form a tapered portion 6.

[0034] Further, the protrusion 53 of the present embodiment includes a second surface 5b and a third surface 5c on both sides of the first surface 5a in the shaft axis direction.

[0035] The second surface 5b defines the end on the tapered tip side of the protrusion 53, and in the present embodiment, it is a surface along the shaft radial direction (for example, a surface with an angle of 5 degrees or less with respect to the shaft radial direction, and the same applies hereinafter). In the present embodiment, at the shaft axis direction position of the second surface 5b, the protruding height t of the protrusion 53 is minimized. Although not particularly limited, at the position of the second surface 5b, the outer diameter D4 of the insertion portion 51 including the protrusion 53 may be formed to be smaller than the first inner diameter D1 of the shaft 2, for example. In this case, when the weight member 5 is inserted into the hollow portion i of the shaft 2, contact between the second surface 5b of the protrusion 53 and the end face of the first end 2a of the shaft 2 can be prevented, and a smoother insertion operation can be realized.

[0036] The third surface 5c defines the end on the tapered rear end side of the protrusion 53, and in this embodiment, it is a surface along the radial direction of the shaft. In this embodiment, at the axial position of the shaft of the third surface 5c, the protruding height t of the protrusion 53 is the maximum. And at the position of the third surface 5c, the outer diameter of the insertion portion 51 including the protrusion 53 forms the maximum outer diameter D3. In this case, in a state where the weight member 5 is inserted into the hollow portion i of the shaft 2, at least the vicinity of the third surface 5c of the protrusion 53 can be elastically compressed and deformed.

[0037] Also, in a state where the weight member 5 is attached to the shaft 2, it is preferable that the entire first surface 5a of the protrusion 53 is in contact with the inner peripheral surface 2i of the shaft 2 (see FIG. 2). In this case, a large contact area between the tapered portion 6 of the protrusion 53 and the inner peripheral surface 2i of the shaft 2 can be ensured, and the weight member 5 can be firmly attached to the inner peripheral surface 2i of the shaft 2. Such an embodiment can be easily realized by adjusting the maximum outer diameter D3 of the weight member 5 and the taper angle of the tapered portion 6 with respect to the first inner diameter D1 of the shaft 2.

[0038] In the golf club 1 of this embodiment, it is desirable that the crushing rate of the protrusion 53 defined by the following formula (1) is 1% to 25%. Crushing rate (%) = (D3 - D1) / D3 * 100 …(1)

[0039] In the above formula (1), D1 is the first inner diameter of the shaft 2, and D3 is the maximum outer diameter of the insertion portion 51 including the protrusion 53. By specifying the crushing rate of the protrusion 53, the insertion operation of the weight member 5 into the shaft 2 and the holding force of the weight member 5 can be optimized. For example, when the crushing rate is less than 1%, the holding force of the weight member 5 with respect to the shaft 2 tends to be small, and there is a possibility that the weight member 5 may fall off or abnormal sounds may occur during swinging during use. From such a viewpoint, the crushing rate is more preferably 5% or more, and even more preferably 10% or more. On the contrary, if the crushing rate exceeds 25%, the insertion operation of the weight member 5 into the shaft 2 may become significantly difficult. From such a viewpoint, the crushing rate is more preferably 20% or less, and even more preferably 15% or less.

[0040] Further, in the golf club 1 of the present embodiment, when the weight of the weight member 5 is W (g) and the total contact area between the plurality of protrusions 53 and the inner peripheral surface 2i of the shaft 2 is S (cm 2 ), it is desirable to satisfy the following formula (2). 2.0 ≦ W / S ≦ 25.0 …(2)

[0041] Formula (2) specifically specifies the weight of the weight member 5 borne by the unit contact area of the protrusion 53. By specifying the ratio W / S in this way, while maintaining the smooth insertion operation of the weight member 5 into the hollow portion i of the shaft 2, it is possible to ensure a high holding force for the weight member 5 having a large weight and suppress dropping off or the like. For example, when the ratio W / S is small, there is no particular problem with the stability after the attachment of the weight member. Practically, it is 2.0 (g / cm 2 ) or more, more preferably 5 (g / cm 2 ) or more, and even more preferably 10 (g / cm 2 ) or more. Conversely, when the ratio W / S exceeds 25.0 (g / cm 2 ), the contact area of the protrusion 53 becomes too small compared to the weight of the weight member 5. As a result, there is a risk of the weight member 5 dropping off or abnormal noise occurring during swinging during use, and the stability after the attachment of the weight member 5 may deteriorate. From such a viewpoint, the ratio W / S is more preferably 20 (g / cm 2 ) or less, and even more preferably 15 (g / cm 2 ) or less.

[0042] In addition, in order to satisfy formula (2), the area of the first surface 5a of the protrusion 53 and / or the number of protrusions 53 may be adjusted in consideration of the weight of the weight member 5. For example, when the area of the first surface 5a is large, as shown in FIG. 7(A), the number of protrusions 53 can be decreased. Conversely, when the area of the first surface 5a is large, as shown in FIG. 7(B), the number of protrusions 53 can be increased.

[0043] [Dimensions of protrusions, etc.] The maximum length L of each protrusion 53 is preferably, for example, 2 mm or more, more preferably 5 mm or more, and even more preferably 10 mm or more in order to obtain a sufficient contact area with the shaft 2. Similarly, in order to impart appropriate compressive rigidity to the protrusion 53, the width of the protrusion measured in the tangential direction in the circumferential direction of the shaft of each protrusion 53 is preferably, for example, 2 mm or more, more preferably 4 mm or more, and even more preferably 6 mm or more.

[0044] [Modified Examples of the Side Shape of the Protrusion] FIGS. 8(A) to (D) show modified examples of the side shape of the protrusion.

[0045] In FIG. 8(A), the side shape of the protrusion is triangular. In this example, the second surface 5b is not substantially present. In this example, since the tapered tip side of the protrusion 53 is connected to the insertion portion 51 without a step, the durability of the protrusion 53 can be improved.

[0046] FIG. 8(B) is a further modification of FIG. 8(A), and the side shape of the protrusion is trapezoidal. For example, in this example, the first surface 5a is formed to constitute a tapered portion 6 and a non-tapered portion 7 having a constant protruding height t in the shaft axis direction. In this example,

[0047] FIGS. 8(C) and (D) are modifications of FIG. 3, in which a groove 9 extending in the circumferential direction of the shaft is formed in the protrusion 53. The cross section of the groove 9 is triangular in FIG. 8(C) and semi-circular in FIG. 8(D). Such a groove 9 helps to promote the deformation of the protrusion 53 and provides a smoother insertion operation.

[0048] Although some embodiments of the present disclosure have been described in detail above, it goes without saying that the present disclosure is not limited to the above specific embodiments and can be implemented in various modes.

Example

[0049] To confirm the effects of the present disclosure, multiple types of weight members were prototyped based on the specifications in Table 1. And the following tests were conducted on them.

[0050] <Assembly workability> Each of the five workers inserted 30 weight members into the shaft and performed an assembly operation of attaching the grip in the next process. The average value of the working time for each weight member (n = 5) was obtained. The results are expressed as an index with Example 3 being 100, indicating that the smaller the numerical value, the better.

[0051] <Mounting stability of the weight member> Using the golf club with each weight member mounted, 3000 balls were struck. Then, the grip was removed and the state of the weight member was checked. The displacement (in the shaft axis direction and the shaft radial direction) from the initial mounting was measured. The results are expressed as an index with Example 3 being 100, indicating that the smaller the numerical value, the better.

[0052] The test results are shown in Table 1.

[0053]

Table 1

[0054] As a result of the test, it was confirmed that the weight members of the examples were stably held inside the shaft without deteriorating productivity.

[0055] [The present disclosure] The present disclosure includes the following aspects. The present disclosure (1) is a golf club, a pipe-shaped shaft having a first end with a first inner diameter D1 and a second end on the opposite side thereof, and having a hollow portion inside, and a weight member mounted on the side of the first end of the shaft, wherein the weight member includes an insertion portion disposed in the hollow portion, an engagement portion that engages with the first end outside the shaft, and a plurality of protrusions protruding in the shaft radial direction from the insertion portion. Each of the protrusions is made of an elastically deformable material, In the state before the weight member is attached to the shaft, The outer diameter D2 of the insertion portion is smaller than the first inner diameter D1 of the shaft, The maximum outer diameter D3 of the insertion portion including the protrusion is larger than the first inner diameter D1, Each of the protrusions includes a tapered portion in which the protruding height in the radial direction of the shaft from the insertion portion decreases toward the second end side, The length Lt of the tapered portion along the shaft axis direction is larger than 50% of the maximum length L of the protrusion along the shaft axis direction, In the state after the weight member is attached to the shaft, at least a part of each of the plurality of protrusions is in contact with the inner peripheral surface of the shaft in a state of being elastically compressed and deformed. It is a golf club.

[0056] The present disclosure (2) is the golf club according to the present disclosure (1), wherein the length Lt of the tapered portion is 95% or more of the maximum length L of the protrusion.

[0057] The present disclosure (3) is the golf club according to the present disclosure (1) or (2), wherein each of the protrusions includes a first surface facing the inner peripheral surface of the shaft, The golf club according to the present disclosure (1) or (2), wherein the entire first surface is in contact with the inner peripheral surface of the shaft.

[0058] The present disclosure (4) is the golf club according to any combination of the present disclosures (1) to (3), wherein the crushing rate of the protrusion defined by the following formula (1) is 1% to 25%. Crushing rate (%) = (D3 - D1) / D3 * 100 …(1) Here, D1 is the first inner diameter of the shaft, and D3 is the maximum outer diameter of the insertion portion including the protrusion.

[0059] The present disclosure (5) is a golf club in any combination with any one of the present disclosures (1) to (4), which satisfies the following formula (2) when the weight of the weight member is W (g) and the total contact area between the plurality of protrusions and the inner peripheral surface of the shaft is S (cm2). 2.0 ≦ W / S ≦ 25.0 …(2)

[0060] The present disclosure (6) is, in the state before the weight member is attached to the shaft, a golf club in any combination with any one of the present disclosures (1) to (5), wherein the centroid of the side surface shape of the protrusion when viewed from the tangential direction in the shaft circumferential direction is located on the first end side rather than the central position of the maximum length along the shaft axial direction of the protrusion.

[0061] The present disclosure (7) is a golf club in any combination with any one of the present disclosures (1) to (6), wherein the protrusions are arranged at equal intervals in the shaft circumferential direction.

[0062] The present disclosure (8) is a weight member for a golf club, wherein the weight member has a first end having a first inner diameter D1 and a second end on the opposite side thereof, and is attached to the side of the first end of a pipe-shaped shaft having a hollow portion inside, the weight member includes an insertion portion for being disposed in the hollow portion, an engagement portion for engaging with the first end outside the shaft, and a plurality of protrusions protruding in the shaft radial direction from the insertion portion, each of the plurality of protrusions is made of an elastically deformable material, the outer diameter D2 of the insertion portion is smaller than the first inner diameter D1 of the shaft, the maximum outer diameter D3 of the insertion portion including the protrusions is larger than the first inner diameter D1, each of the protrusions includes a tapered portion in which the protruding height in the shaft radial direction from the insertion portion decreases toward the second end side, the length Lt of the tapered portion along the shaft axial direction is larger than 50% of the maximum length L of the protrusion along the shaft axial direction, It is a weight member for a golf club.

[0063] The present disclosure (9) is the weight member for a golf club according to the present disclosure (8), wherein the length Lt of the tapered portion is 95% or more of the maximum length L of the protrusion.

[0064] The present disclosure (10) is the golf club according to the present disclosure (8) or (9), wherein the centroid of the side shape of the protrusion as viewed from the tangential direction in the circumferential direction of the shaft is located on the first end side rather than the central position of the maximum length along the shaft axis direction of the protrusion.

Explanation of Signs

[0065] 1 Golf club 2 Shaft 2a First end of the shaft 2b Second end of the shaft 2i Inner circumferential surface of the shaft 5 Weight member 5a First surface of the weight member 6 Tapered portion 51 Insertion portion 52 Engagement portion 53 Protrusion i Hollow portion of the shaft

Claims

1. A golf club, comprising: a pipe-shaped shaft having a first end with a first inner diameter D1 and a second end on the opposite side thereof, and having a hollow portion inside; a weight member attached to the side of the first end of the shaft; the weight member includes an insertion portion disposed in the hollow portion, an engagement portion that engages with the first end outside the shaft, and a plurality of protrusions protruding in the radial direction of the shaft from the insertion portion; each of the protrusions is made of an elastically deformable material; in a state before the weight member is attached to the shaft, the outer diameter D2 of the insertion portion is smaller than the first inner diameter D1 of the shaft; the maximum outer diameter D3 of the insertion portion including the protrusions is larger than the first inner diameter D1; each of the protrusions includes a tapered portion whose protrusion height in the radial direction of the shaft from the insertion portion decreases toward the second end side; the length Lt of the tapered portion along the shaft axis direction is larger than 50% of the maximum length L of the protrusion along the shaft axis direction; in a state after the weight member is attached to the shaft, at least a part of each of the plurality of protrusions is in contact with the inner peripheral surface of the shaft in a state of being elastically compressed and deformed; A golf club.

2. The golf club according to claim 1, wherein the length Lt of the tapered portion is 95% or more of the maximum length L of the protrusion.

3. each of the protrusions includes a first surface facing the inner peripheral surface of the shaft; The golf club according to claim 1 or 2, wherein in a state after the weight member is attached to the shaft, all of the first surfaces are in contact with the inner peripheral surface of the shaft.

4. The golf club according to any one of claims 1 to 3, wherein the crushing rate of the protrusion defined by the following formula (1) is 1% to 25%. Crushing rate (%) = (D3 - D1) / D3 * 100... (1) Here, D1 is the first inner diameter of the shaft, and D3 is the maximum outer diameter of the insertion portion including the protrusions.

5. Let the weight of the hammer member be W (g), and let the total contact area between the plurality of protrusions and the inner peripheral surface of the shaft be S (cm ２ ). The golf club according to any one of claims 1 to 4, which satisfies the following formula (2). 2.0 ≦ W / S ≦ 25.0... (2)

6. In a state before the weight member is attached to the shaft, The golf club according to any one of claims 1 to 5, wherein the centroid of the side surface shape of the protrusion viewed from the tangential direction in the circumferential direction of the shaft is located closer to the first end side than the central position of the maximum length of the protrusion along the shaft axis direction.

7. The golf club according to any one of claims 1 to 6, wherein the protrusions are arranged at equal intervals in the circumferential direction of the shaft.

8. A weight member for a golf club, wherein the weight member has a first end having a first inner diameter D1 and a second end on the opposite side thereof, and is attached to the side of the first end of a pipe-shaped shaft having a hollow portion inside. The weight member includes an insertion portion for arranging inside the hollow portion, an engagement portion for engaging with the first end outside the shaft, and a plurality of protrusions protruding in the radial direction of the shaft from the insertion portion. Each of the plurality of protrusions is made of an elastically deformable material. The outer diameter D2 of the insertion portion is smaller than the first inner diameter D1 of the shaft. The maximum outer diameter D3 of the insertion portion including the protrusions is larger than the first inner diameter D1. Each of the protrusions includes a tapered portion in which the protruding height in the radial direction of the shaft from the insertion portion decreases toward the second end side. The length Lt of the tapered portion along the axial direction of the shaft is larger than 50% of the maximum length L of the protrusion along the axial direction of the shaft. A weight member for a golf club.

9. The weight member for a golf club according to claim 8, wherein the length Lt of the tapered portion is 95% or more of the maximum length L of the protrusion.

10. The golf club according to claim 8 or 9, wherein the centroid of the side shape of the protrusion when viewed from the tangential direction in the circumferential direction of the shaft is located closer to the first end side than the central position of the maximum length of the protrusion along the axial direction of the shaft.

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