Golf club shaft and golf club

Abstract

To provide a shaft for a golf club having high vibration attenuation effect, capable of adjusting the weight balance easily, and not causing discomfort during its use.SOLUTION: In a shaft 10 for a golf club formed by connecting three or more shaft parts 11, 12, 13 in the axial direction. Adjacent shaft parts are not superposed in the axial direction, and joining members 20, 30 are provided to allow edges of each shaft part to abut thereon so as to be fixed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a shaft for a golf club, and more particularly to a shaft for a golf club made up of a plurality of parts, and a golf club equipped with such a shaft. [Background technology]

[0002] Conventionally, shafts used in golf clubs (especially putter clubs) have been known to be made of FRP, which is formed from a prepreg sheet made of reinforcing fibers impregnated with synthetic resin, or steel.Recently, composite shafts that combine FRP and steel shaft parts have also become known, such as the Stability Shaft developed by BGT (Non-Patent Document 1) and the Stroke Lab Shaft attached to Callaway putter clubs (Non-Patent Document 2).

[0003] The composite shaft is made of FRP from the middle to the handle, and steel from the middle to the tip, with the two parts connected axially by joining materials (joint parts) made of metal, resin, etc. [Prior art documents] [Patent documents]

[0004] [Non-Patent Document 1] https: / / stabirityshaft.jp [Non-patent document 2] https: / / callawaygolf.jp / special / strokelab#2019 / Summary of the Invention [Problem to be solved by the invention]

[0005] Because the stability shaft is constructed by connecting two shafts (one made of FRP and the other made of steel) axially with a joint, the difference in shaft diameter at the joint is large, making it difficult to see when setting up and prone to feeling uncomfortable. The Stroke Lab shaft, on the other hand, has a small difference in diameter at the joint, but the shaft is thin, resulting in a large difference in thickness between the grip and the shaft, which also tends to feel uncomfortable. Furthermore, because the composite shaft connects the two shafts on both sides of the joint (two joints), it has little vibration damping effect. Furthermore, because the heavier shafts are located in the middle or near the grip end, it is difficult to achieve an appropriate weight balance, taking into account the club's center of gravity, etc.

[0006] The present invention has been made in light of the above-mentioned problems, and aims to provide a golf club shaft and a golf club that have a high vibration damping effect, are easy to adjust the weight balance, and do not cause any discomfort when used. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the golf club shaft of the present invention is characterized in that it has three or more shaft parts connected in the axial direction, and has joining members that abut and fix the end edges of each shaft part without adjacent shaft parts overlapping in the axial direction.

[0008] The above-mentioned golf club shaft is divided into three or more shafts, and adjacent shaft parts are fixed with joining members, so it is possible to reduce the difference in diameter between adjacent shafts (difference in outer diameter of the shaft at the joint), and discomfort during use is suppressed. Furthermore, because three or more shafts are joined and fixed, the vibration damping effect is enhanced, and the number of positions for the joining members increases, making it easier to adjust the weight balance.

[0009] The present invention is also characterized by a golf club having the shaft of the above-described configuration. In this case, golf clubs include iron clubs, wood clubs (drivers, fairway woods, utilities), putter clubs, etc., but this configuration is particularly suitable for putter clubs because it makes it easy to see the shaft during a swing and enables a stable stroke to be achieved. [Effects of the Invention]

[0010] According to the present invention, a golf club shaft and a golf club can be obtained that have a high vibration damping effect, are easy to adjust the weight balance, and do not cause discomfort when used. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram showing an embodiment of a golf club (putter club) according to the present invention. [Figure 2] (a) is a side view of the joint member (base joint member) used in the golf club shown in Figure 1, (b) is a view of Figure (a) from the tip side, and (c) is a view of Figure (a) from the base side. [Figure 3] (a) is a side view of the joint member (tip joint member) used in the golf club shown in Figure 1, (b) is a view of Figure (a) from the tip side, and (c) is a view of Figure (a) from the base side. [Figure 4] 10A and 10B are diagrams showing another embodiment of the present invention, in which (a) is a side view showing the tip-side joining member, (b) is a diagram of (a) as seen from the tip side, and (c) is a diagram of (a) as seen from the base end side. [Figure 5] 5 is a diagram showing a golf club (putter club) on which the tip-side joining member of FIG. 4 is disposed. [Figure 6] 1 is a graph showing an example of weight distribution of a golf club shaft. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a golf club shaft and a golf club according to the present invention will be described with reference to the accompanying drawings. 1 is a diagram showing an embodiment of a golf club. The golf club 1 according to this embodiment is configured as a putter club with a head 50 attached to the tip of a shaft 10, and a grip 60 attached to the base end of the shaft 10.

[0013] The head 50 is made of metal and has a ball-striking surface 51, and a hosel portion 52 is formed on the upper surface on the heel side so as to protrude upward. A shaft connecting portion (socket) 53 having a shaft fixing hole is provided at the tip of the hosel portion 52, and the tip side of the shaft 10 is fitted into and fastened to the shaft fixing hole, thereby integrating the head 50 and the shaft 10. Note that the configuration (shape, size, etc.) of the head 50 and the method of fixing the head 50 and the shaft 10 can be modified in various ways and are not limited to a specific structure.

[0014] The shaft 10 is constructed by connecting three or more shaft parts in the axial direction, and in this embodiment, it is constructed by three shaft parts. Hereinafter, with regard to these three shaft parts, the part to which the grip 60 is attached will be referred to as the base shaft 11, the part to which the head 50 is attached will be referred to as the tip shaft 13, and the shaft disposed between them will be referred to as the intermediate shaft 12. These divided shaft parts are constructed as a single shaft by disposing joining members 20, 30 between the base shaft 11 and the intermediate shaft 12, and between the intermediate shaft 12 and the tip shaft 13, which connect and fix the shafts together.

[0015] The three or more shaft parts include those made of FRP, which is formed from prepreg sheets made of fiber-reinforced resin material in which reinforcing fibers are impregnated with synthetic resin. In this embodiment, all three shaft parts are configured as FRP tubular bodies. The shaft parts may also include steel tubular bodies. For example, if the shaft of a golf club that has been used until now is made of steel, cutting the tip end of the shaft, installing a joining member in that section, and connecting and fixing an FRP intermediate shaft and base shaft further rearward makes it possible to easily adjust the balance (customize) of the existing golf club.

[0016] The FRP shaft parts can be modified as needed in terms of length, weight, thickness, the configuration of the reinforcing fibers in the prepreg sheets, the amount of resin impregnation, the number of windings, the arrangement pattern, etc. The shaft parts may also be solid.

[0017] The joining members 20, 30 that connect and fix the adjacent shafts together are configured so that the edges of the adjacent shaft parts abut and are fixed together without overlapping in the axial direction. In other words, in the connected and fixed state, the edges of the adjacent shafts are spaced apart (separated) in the axial direction by the joining members, which increases the damping effect of vibrations when hitting the ball with the head and makes it possible to improve the feel on impact.

[0018] The joint member 20 disposed between the butt end shaft 11 and the intermediate shaft 12 is preferably located closer to the grip than the middle of the shaft. Also, the joint member 30 disposed between the intermediate shaft 12 and the tip shaft 13 is preferably located closer to the tip than the middle of the shaft. By disposing the joint members 20, 30 on both sides of the middle of the shaft in this way, it becomes possible to stabilize the stroke of a putter club. In particular, by setting the center of gravity of the golf club to the position of the joint member 30, the player can visually become aware of the center of gravity position (heavy part), which makes it possible to stabilize the stroke.

[0019] Next, the configuration of the joining members 20 and 30 will be described with reference to FIG. 2 and FIG. 3 in addition to FIG. The weight of the joining members 20, 30 is determined appropriately in consideration of the specifications of the golf club, the specifications of the shaft, the weight of the head, the overall shaft balance, etc., with 10 to 20 g being used for the tip joining member 30 and 20 to 30 g or 20 to 40 g being used for the butt joining member 20. In this case, the constituent material of the joining members 20, 30 is not particularly limited, but they can be integrally formed from hard resin, metal, etc.

[0020] 2, the joining member 20 includes an exposed main body portion 21 and protruding portions 22, 23 that protrude from the main body portion 21 on both sides in the axial direction and are joined to the inner circumferential surfaces of the shaft parts (the base shaft 11 and the intermediate shaft 12). The tip side of the base shaft 11 is fitted into the protruding portion 22, and the base end side of the intermediate shaft 12 is fitted into the protruding portion 23. In this case, the end edges 11a, 12a of the fitted shafts 11, 12 abut against step portions 22b, 23b formed on both axial sides of the main body portion 21, and the surfaces of the respective shafts are configured to be flush with the surface of the main body portion 21 when they are in contact with the step portions.

[0021] In this embodiment, the inner circumferential surfaces of the shafts 11, 12 and the outer circumferential surfaces of the protrusions 22, 23 are fixed to each other by adhesive. For this reason, it is preferable to form, for example, irregularities 22a, 23a that are continuous along the axial direction on the surfaces of the protrusions 22, 23 to enhance the anchoring effect. Such irregularities can be appropriately modified, for example, by forming them in a ring shape or a spiral shape that is continuous along the axial direction, as shown in Figure 2, or by roughening the surface. Alternatively, by forming a female thread on the inner peripheral surface of each shaft 11, 12 and a male thread on the outer peripheral surface of the protrusions 22, 23 to form a detachable structure by a screw-engagement structure, it becomes possible to easily replace and disassemble the shaft parts and connecting members. Also, the screw-engagement method using a male thread and a female thread can be implemented in the internal structure of the main body 21.

[0022] Here, specific dimensions of the diameters of the shaft parts 11, 12, and 13 and the joining members 20 and 30 will be described with reference to FIGS. 2 and 3. FIG. In this embodiment, the base shaft 11, the intermediate shaft 12, and the tip shaft 13 are configured as straight tubular bodies, but they may also be configured to have a tapered shape.

[0023] The inner diameter D1 of the base shaft 11 (outer diameter of the protruding portion 22 of the joining member 20) is 12.80 mm, and its outer diameter D2 (outer diameter of the stepped portion 22b of the joining member 20) is 15.00 mm. Therefore, the thickness of the base shaft 11 is 2.20 mm. The edge 11a of the thick base shaft 11 abuts against the stepped portion 22b, so that the surface of the base shaft 11 and the main body 21 are flush with each other. Note that there is a slight clearance (for example, about 0.1 mm) between the inner diameter of the base shaft 11 and the outer diameter D1 of the protruding portion 22 of the joining member 20 so that the base shaft can be inserted. In other words, the inner diameter of the base shaft 11 and the outer diameter D1 of the protruding portion 22 of the joining member 20 do not need to strictly match.

[0024] The inner diameter D3 of the intermediate shaft 12 (the outer diameter of the protrusion 23 of the joining member 20) is 7.80 mm, and its outer diameter D4 (the outer diameter of the step 23b of the joining member 20) is 12.00 mm. Therefore, the thickness of the intermediate shaft 12 is 4.20 mm. The edge 12a of the intermediate shaft 12, which has this thickness, abuts against the step 23b, so that the surface of the intermediate shaft 12 and the main body 21 are flush with each other. According to the above-described configuration, the base shaft 11 is formed to have a larger diameter and a thinner wall thickness than the intermediate shaft 12.

[0025] The main body 21 of the joining member 20 has a tapered surface so that the difference in outer diameter between the base shaft 11 and the intermediate shaft 12 (the difference in outer diameter between 15.00 mm and 12.00 mm; 3.00 mm) appears visually natural. In this case, the axial length L of the main body 21 depends on the thickness and diameter of the shafts 11 and 12. If the length is too short, the difference in diameter becomes easily noticeable, while if the length is too long, the weight becomes too heavy (the weight of the shaft after the individual parts are joined). Therefore, it is preferable that the axial length L of the main body 21 is in the range of 10 mm to 50 mm. In this embodiment, the axial length L of the main body 21 is set to 30 mm, which allows the difference in outer diameter between the base shaft 11 and the intermediate shaft 12, which are formed in a straight shape, to be seamlessly connected.

[0026] If the axial lengths L1, L2 of the protrusions 22, 23 are too short, the joint strength will be weak and the shaft will be prone to bending, while if they are too long, the weight will increase, so it is preferable that they be formed in the range of 40 mm to 60 mm in the axial direction. In this embodiment, the axial lengths L1, L2 of the protrusions 22, 23 are both set to 50 mm, which increases the joint strength and prevents the shaft from bending. It should be noted that the protrusion can be made long in the axial direction and hollowed out to reduce its weight, thereby making it possible to increase the axial length.

[0027] 3, the joining member 30 includes an exposed main body portion 31 and protruding portions 32, 33 that protrude from the main body portion 31 on both sides in the axial direction and are joined to the inner circumferential surfaces of the shaft parts (intermediate shaft 12 and tip shaft 13). The tip side of the intermediate shaft 12 is fitted into the protruding portion 32, and the base end side of the tip shaft 13 is fitted into the protruding portion 33. In this case, the respective end edges 12a, 13a of the fitted shaft parts 12, 13 are abutted against step portions 32b, 33b of the main body portion 31, and the surfaces of the shafts are configured to be flush with the surface of the main body portion 31 when abutting against the step portions.

[0028] The inner peripheral surfaces of the shafts 12, 13 and the outer peripheral surfaces of the protrusions 32, 33 are fixed together by adhesive. For this reason, it is preferable to form, for example, irregularities 32a, 33a that are continuous along the axial direction on the surfaces of the protrusions 32, 33 to enhance the anchoring effect. Such irregularities can be appropriately modified, for example, by forming them in a ring shape or a spiral shape that is continuous along the axial direction, as shown in Figure 3, or by roughening the surface. Alternatively, by forming a female thread on the inner peripheral surface of each shaft 12, 13 and a male thread on the outer peripheral surface of the protrusions 32, 33 to form a detachable structure by a screw-engagement structure, it becomes possible to easily replace and disassemble the shaft parts and connecting members. Also, the screw-engagement method using a male thread and a female thread can be implemented in the internal structure of the main body 31.

[0029] The proximal end side of the joining member 30 is fitted with and fixed to the tip portion of the straight intermediate shaft 12, and therefore the outer diameter D3 of the protruding portion 32 of the joining portion 30 and the outer diameter D4 of the step portion 32b are set to be the same as the outer diameter D3 of the protruding portion 23 of the joining member 20 and the outer diameter D4 of the step portion 23b. However, this is not limited to the case where the intermediate shaft 12 has a tapered shape.

[0030] The proximal end portion of the straight tip shaft 13 is fitted and fixed to the distal end side of the joining member 30. The inner diameter D5 of the tip shaft 13 (the outer diameter of the protruding portion 33 of the joining member 30) is 4.80 mm, and the outer diameter D6 (the outer diameter of the stepped portion 33b of the joining member 30) is 9.40 mm. Therefore, the thickness of the tip shaft 13 is 4.60 mm. The thick edge 13a of the tip shaft 13 abuts against the stepped portion 33b, so that the surface of the tip shaft 13 and the main body portion 31 are flush with each other. Note that a small clearance (e.g., about 0.1 mm) is provided between the inner diameter of the tip shaft 13 and the outer diameter D5 of the protruding portion 33 of the joining member 30 to allow insertion of the tip shaft. In other words, the inner diameter of the tip shaft 13 and the outer diameter D5 of the protruding portion 33 of the joining member 30 do not need to strictly match.

[0031] According to the above configuration, the tip shaft 13 is formed to have a smaller diameter and a thicker wall thickness than the intermediate shaft 12. That is, the above-described three shaft parts 11 to 13 are formed so that the thickness of the base shaft 11 < the thickness of the intermediate shaft 12 < the thickness of the tip shaft 13, and so that the outer diameter of the base shaft 11 > the outer diameter of the intermediate shaft 12 > the outer diameter of the tip shaft 13.

[0032] The main body 31 of the joining member 30 has a tapered surface so that the difference in outer diameter between the intermediate shaft 12 and the tip shaft 13 (12.00 mm and 9.40 mm) appears visually natural. In this case, the axial length L of the main body 31 depends on the thickness and diameter of the shafts 12 and 13. If the length is too short, the difference in diameter becomes easily noticeable, while if the length is too long, the weight becomes too heavy (the weight of the shaft after the parts are joined). Therefore, it is preferable that the axial length L of the main body 31 is in the range of 10 mm to 40 mm. In this embodiment, the axial length L of the main body 31 is set to 20 mm, which allows the difference in outer diameter between the straight-shaped intermediate shaft 12 and the tip shaft 13 to seamlessly transition.

[0033] Furthermore, if the axial lengths L1, L2 of the protrusions 32, 33 are too short, the joint strength will be weak and the shaft will be prone to bending, while if they are too long, the weight will increase, so they are preferably formed in the axial range of 40 mm to 60 mm. In this embodiment, the axial lengths L1, L2 of the protrusions 32, 33 are both set to 50 mm, which increases the joint strength and prevents bending of the shaft. It is also possible to reduce the weight of the protruding portion by forming it long in the axial direction and forming the inside of it hollow.

[0034] The proximal end portion of the straight tip shaft 13 is fitted and fixed into the protruding portion 33 on the tip side of the joining member 30. Not only a shaft with a normal outer diameter of about 9.4 mm, but also a thick-walled shaft with a large diameter (over-hosel type) may be used. For example, a large-diameter shaft, such as a tip shaft with an outer diameter of 12.0 mm, can be used for the tip shaft 13. By using such a large-diameter shaft, it becomes possible to provide a large-diameter shaft or a highly rigid shaft (tip shaft) in the tip portion, which is prone to bending and twisting in conventional shafts. When using a large-diameter tip shaft or a tip shaft with a small diameter difference from the intermediate shaft, the shape and diameter of the main body 31 of the joining member 30 and the outer diameters of the protruding portions 32 and 33 can be appropriately modified.

[0035] As described above, by making the shaft of a golf club (putter club) into a three-piece structure (three straight shaft parts: base shaft 11, intermediate shaft 12, and tip shaft 13), and connecting and fixing each shaft with joining members 20 and 30, the following effects can be obtained.

[0036] As described above, by connecting and fixing the three shaft parts with two joining members, the base shaft 11 to which the grip 60 is attached can be made thick, and the tip shaft 13 can be made thin so that the head can be attached. Moreover, because the intermediate shaft 12 is provided, even if there is a large difference in outer diameter between the base and tip ends, the tapered main bodies 21, 31 exposed by the joining members 20, 30 can provide a shaft structure that feels natural.

[0037] Furthermore, because the joining members 20 and 30 connect and fix the edge portions of adjacent shaft parts in a separated state (a state in which different materials are separated) without overlapping, the vibration damping effect is enhanced and the hitting feel is improved. In particular, because the shaft is composed of five parts (two joining members and three shaft parts), the vibration damping effect is enhanced compared to a conventional two-piece shaft structure.

[0038] Furthermore, because the connecting members 20 and 30 are heavy, concentrating the weight of the shaft at the connecting members and reducing the weight of each shaft part eliminates the need to increase the total weight of the shaft. In this case, for example, as shown in FIG. 6, in a putter club, the shaft length is approximately 850 mm, and connecting member 30 is disposed within a range of approximately 100 to 210 mm from the tip, and connecting member 20 is disposed within a range of approximately 380 to 500 mm from the tip. This allows the shaft to have areas where weight is concentrated at the tip end (head side) and the base end (grip side). In particular, by positioning the weight of connecting member 20 directly below the portion where grip 60 is attached, unnecessary movement during the swing is reduced, resulting in a simpler stroke and a more stable feel.

[0039] Furthermore, by positioning the weight by the joint member 30 at the tip side, the trajectory of the head is stabilized, and the stroke can be stabilized. In this case, by setting the center of gravity of the golf club to be the position of the joint member 30, the player can be made aware of the center of gravity position (heavy part) visually, and with golf clubs such as putter clubs, the stroke can be made more stable.

[0040] In addition, in this embodiment, each shaft part is configured to be straight, which improves moldability and also improves anisotropy. In this case, the tapered main body parts 21, 31 where the joining members 20, 30 are exposed reduce the difference in outer diameter between adjacent shaft parts, improving the appearance. In particular, this effect can be enhanced by increasing the axial length of the main body parts 21, 31.

[0041] Furthermore, it becomes easier to mold shafts with locally changed materials, lengths, weights, rigidity, wall thicknesses, and outer diameters, increasing customizability. For example, by increasing the diameter of the tip shaft 13 or using a highly rigid carbon material, it becomes possible to effectively strengthen parts that are prone to bending and twisting. Furthermore, the joining members 20 and 30 reduce the hollow portion of the shaft, making it easier to set the desired stiffness and torque in that part.

[0042] Furthermore, when using a thin-diameter tip shaft 13, particularly in a putter club, the tip side is likely to buckle, so bonding the tip shaft 13 to the outside can increase its strength against buckling. Also, simply by changing the tip shaft and the joining member, it becomes possible to easily replace it with not only a shaft with a normal outer diameter, but also a shaft with a large diameter.

[0043] Figures 4 and 5 are diagrams showing another embodiment of the present invention, with Figures 4(a) to 4(c) showing a tip-side joining member, and Figure 5 showing a golf club (putter club) provided with the tip-side joining member of Figure 4. Note that parts similar to those in Figure 1 are given the same reference numerals, and detailed explanations will be omitted.

[0044] In this embodiment, the tip-side joining member 40 has an exposed main body portion 41 and an axial hole 43 formed in the main body portion 41 and joining the outer peripheral surface of the base end side of the tip-side shaft 13 .

[0045] The base end side of the tip shaft 13 is fitted into the axial hole 43, and the inner peripheral surface of the axial hole 43 and the base end side outer peripheral surface of the tip shaft 13 are fixed by adhesive with the end edge 13a of the tip shaft 13 abutting against the bottom of the axial hole 43. Also, a protrusion 42 that is fitted into the inner peripheral surface of the intermediate shaft 12 is provided on the base end side of the main body 41, similar to the configuration shown in Fig. 3. The end edge 12a of the intermediate shaft 12 that is fitted into the protrusion 42 abuts against a step 42b of the main body 41 and is configured to be flush with the surface of the main body 41 when abutting against the step.

[0046] 3, it is preferable to form, for example, unevenness 42a continuously along the axial direction on the surface of protrusion 42 to enhance the anchoring effect. It is also preferable to form unevenness (not shown) continuously along the axial direction on the inner peripheral surface of axial hole 43 to enhance the anchoring effect.

[0047] The proximal end portion of the straight tip shaft 13 is fitted and fixed into the axial hole 43 on the tip side of the joining member 40. Specifically, by providing adhesive portions on the outer peripheral surface of the tip shaft 13, it is possible to install a shaft with a small inner diameter that is unsuitable for joining to the protruding portion 33 on the tip side of the joining member 30 (for example, a tip shaft with an outer diameter D5 of 4 mm or less) or a solid shaft. That is, in the configuration of the joining member 30 described above, when a shaft with a small inner diameter is used (which may lead to shaft breakage starting from the boundary with the main body portion 31) or when a solid shaft that does not fit into the protruding portion 33 is used, it is preferable to use the joining member 40 with the configuration described above (the configuration shown in FIG. 4). However, if the joining member 30 is made of a strong material, it is possible to use the joining member 30 even with a shaft with a small inner diameter.

[0048] It is preferable that the inner diameter D7 of the axial hole 43 of the joining member 40 be slightly different from the outer diameter D4 of the step portion 42b of the main body 41 against which the end edge of the intermediate shaft abuts. Specifically, for example, by ensuring that the difference between the inner diameter D7 and the outer diameter D4 (thickness of the main body 41) is 1 mm or more, the thickness of the main body 41 does not become too thin, which would reduce the strength of the main body 41. Of course, if the joining member 40 is made of a strong material, it can be used even if the thickness of the main body 41 is less than 1 mm.

[0049] The axial length L' of the main body 41 only needs to be the same as the length L2 of the protrusion 33 shown in Fig. 3, and may be in the range of 40 mm to 70 mm in the axial direction. In this embodiment, the axial length L' of the main body 41 is set to 60 mm, including the length of the bonded portion by the axial hole 43, which is approximately 50 mm. This increases the joining strength and prevents bending of the shaft.

[0050] Furthermore, the axial length L1' of the protrusion 42 should be the same as the length L1 of the protrusion 32 shown in Fig. 3, and is preferably formed in the range of 40 mm to 60 mm in the axial direction. The axial length L1' of the protrusion 42 in this embodiment is set to 50 mm, which increases the joining strength and prevents bending of the shaft.

[0051] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be modified in various ways. The present invention is only required to have a structure in which the golf club shaft is divided into three or more pieces (three or more shaft parts) and has joining members that secure the edges of each shaft part by abutting them together, and the configuration of each shaft part (material, thickness, outer diameter, inner diameter, rigidity, etc.) can be modified as appropriate. Furthermore, the number of shaft parts can be four or more, and the position and configuration of the joining members (material, exterior design, weight, length, joining structure with adjacent shaft parts, etc.) can also be modified as appropriate.

[0052] Furthermore, although the joining member in this embodiment is configured so that the edges of adjacent shaft parts abut against the main body to prevent the shaft parts from overlapping in the axial direction, it may be configured so that the edges of adjacent shaft parts abut against each other to connect and fix them. Furthermore, although a putter club is exemplified as a golf club in the above embodiment, the present invention can also be applied to an iron club. [Explanation of symbols]

[0053] 1. Golf club (putter club) 10 shaft 11. Base shaft (shaft part) 12 Intermediate shaft (shaft parts) 13 Tip shaft (shaft part) 20,30 Joint members 50 head 60 Grip

Claims

1. A golf club shaft in which three or more shaft parts are connected in the axial direction, The shaft parts have a joining member that abuts and fixes the edges of the shaft parts together without overlapping with each other in the axial direction, The joining members are arranged in a range of 100 to 210 mm and a range of 380 to 500 mm from the tip of the golf club shaft. A shaft for a golf club.

2. 2. The shaft for a golf club according to claim 1, wherein the three or more shaft parts include parts made of FRP formed from a prepreg sheet of fiber-reinforced resin material in which reinforcing fibers are impregnated with synthetic resin, and parts made of steel.

3. 3. The golf club shaft according to claim 1, wherein the joining member has an exposed main body portion and a protruding portion that protrudes axially from the main body portion and is joined to the inner circumferential surface of the shaft part.

4. 4. The golf club shaft according to claim 3, wherein the outer peripheral surface of the protrusion is formed with unevenness that continues in the axial direction.

5. 4. The golf club shaft according to claim 1, wherein the joining member has an exposed main body portion and an axial hole formed in the main body portion for joining the outer peripheral surface of the shaft part.

6. 6. The golf club shaft according to claim 5, wherein the inner peripheral surface of the axial hole is formed with unevenness that continues in the axial direction.

7. 7. The golf club shaft according to claim 3, wherein the main body portion from which the joining member is exposed has a taper that gradually reduces in diameter toward the tip end.

8. 8. The golf club shaft according to claim 7, wherein the exposed main body portion of the joining member is formed to have an axial length of 10 mm to 70 mm.

9. The shaft parts are composed of three parts: a base shaft to which a grip is attached, a tip shaft to which a head is attached, and an intermediate shaft disposed between them; 9. The golf club shaft according to claim 1, wherein the joint members are disposed between the tip shaft and the intermediate shaft, and between the base shaft and the intermediate shaft.

10. A golf club comprising the golf club shaft according to any one of claims 1 to 9.

11. 11. The golf club according to claim 10, wherein the center of gravity of the golf club is set at the position of the connecting member.

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