Golf club shaft structure

Abstract

We provide shaft structures for golf clubs. [Solution] The shaft structure is composed of alternating overlaps of carbon fiber layers 20" and at least one layer of plastic film 21", and / or metal sheets 22" with a thickness of less than 0.2 mm (200 μm; 0.0079 inch), with all material layers in contact with a thermosetting epoxy resin or thermoplastic matrix substrate, and formed by heat curing. In this way, the dissimilar materials of the entire shaft are bonded together to provide suitable elasticity, high toughness, excellent vibration damping ability, and create higher power transmission and operability, making it easier to accurately control long-distance drivers and short-distance putters, and providing vibration damping ability and a unique shot feel for long-distance drivers.

Description

Technical Field

[0001] This application claims priority based on Utility Model Registration No. 114201500, a Taiwan application filed on February 13, 2025, and incorporates by reference all the descriptions contained in the current Taiwan application.

Background Art

[0002] The present invention relates to golf supplies, and more particularly to a shaft structure of a golf club that has the characteristics of metal, carbon fiber, and plastic materials and can provide excellent elasticity, toughness, flexibility, vibration damping, a unique shot feeling, and control force for the shaft of a golf club.

[0003] In golf, different golf clubs are used according to the differences in the required shots. Therefore, there are also differences in the design of the heads of golf clubs. For example, in the case of the "driver" used first, since it is necessary to hit the shot to a position close to the green hole, the head shape is different from the design of the "putter" used near the green hole. There are already many new structures in such head designs. Also, regarding the shaft of a golf club, the initial single-material carbon fiber material has been continuously improved to the current one manufactured from a plurality of materials with a carbon fiber material added to a metal material. Starting from the thermosetting epoxy resin (Thermoset, TS) of the prepreg base material being heated and cured to be stably cured integrally to form a carbon fiber layer, it provides various choices for golf enthusiasts.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when using a golf club shaft, the user's own feel and force were extremely important for the accuracy and stability of ball control, especially when using a putter or driver. Aside from daily practice, the combination of materials used for the club head and shaft also had a direct impact. For example, using a metal shaft made it heavier, increasing the stability of the expected shot trajectory and spin for both putters and drivers (though the ball's spin and flight distance were shortened). Using a carbon fiber shaft made it lighter, increasing the expected spin and flight distance for both putters and drivers (though the stability of the ball's trajectory and spin decreased). Thus, by selecting a shaft (metal or carbon fiber) that suits the individual's shot stance and force, ideal ball control could be nearly achieved. However, for beginner golfers, selecting a suitable shaft (metal or carbon fiber) based on their shot stance and force was extremely difficult. For experienced players, the ability to choose a shaft that suits them is a plus; however, the shafts are limited to metal or carbon fiber materials, making it more difficult to control the ball's spin on expected shots with a putter or driver. In particular, the stability of the driver's trajectory and spin, as well as long shots and accuracy, have become even more difficult to control.

[0005] Furthermore, the shafts of the aforementioned golf clubs utilize carbon fiber materials in addition to metal materials, offering golfers another option. On the surface, a "putter" or "driver" that combines the aforementioned metal material with carbon fiber material appears to comprehensively enhance the stability of the golf ball's trajectory and spin, or its long shots and accuracy. However, this is not actually the case. The difference in thermal expansion coefficients between the carbon fiber layer and the metal material layer of the composite material is extremely large, resulting in a very large difference in volume change between the two. This leads to very large delamination stresses between the layers of different materials, causing delamination at the contact surface between the two different materials. This makes the bonding between the carbon fiber layer and the metal material layer of the composite material unstable, significantly affecting performance, and in the worst case, compromising safety. During use over a certain period, the aforementioned golf club receives a strong impact force at the moment of a shot. Because the metal layer is too thick, when the golf shaft is subjected to the high stress and instantaneous intensity and impact force of a shot on a daily basis, an extremely large difference in the coefficient of thermal expansion occurs between each carbon fiber layer and the metal material layer. This huge difference in volume change between the two materials results in very large delamination stress between the layers of different materials, causing delamination to occur at the contact surface between each carbon fiber layer and the metal material layer. This has a serious impact on performance, and the entire structure of the golf shaft becomes unusable. In short, the thickness of the metal material layer in the golf club shaft directly affects the stability of the bond at the joint surface with the carbon fiber layer.

[0006] Furthermore, referring to Figure 1, the structure of a golf club shaft that incorporates carbon fiber material in addition to other metal materials is further understood to be comprised of an inner carbon fiber layer 51 and an outer metal layer 52, where the carbon fiber layer 51 is composed of multiple carbon fiber prepregs having different angles. The metal layer 52 is formed by metal threads spirally wound around the outer surface of the carbon fiber layer 51, so the entire shaft structure is not completely covered by the metal threads, but rather a net-like surface is formed. Thus, the carbon fiber layer 51 is not completely covered by the metal threads, and the net-like gaps in the metal layer 52 make it difficult to control the spin of the ball on a shot expected by a putter or driver. In particular, the stability of the golf ball's spin on a driver's trajectory, or the control of long shots and accuracy, has become difficult. The main reason for this was that after a shot, only a portion of the force received by the carbon fiber layer 51 of the entire shaft 5 was absorbed by the metal threads wrapped around the outer surface of the carbon fiber layer 51 of the metal layer 52, while the majority of the force was released by passing through the gaps in the net-like surface of the metal layer 52. This is because the thermoplastic PVB film was not sandwiched "entirely" between the two glass intermediate layers, and only something similar to a net was added between the intermediate layers, leaving gaps where, upon impact, the impact would pass through and be released, scattering glass fragments. Therefore, in such a shaft 5, the effect of absorbing the impact force of the shot, which is achieved by adding the metal threads to the outer surface of the carbon fiber layer 51, was not realized, and the golf ball control effect was basically equivalent to that before the metal threads were wrapped around it.

[0007] Furthermore, in golf, when hitting the ball with a driver, there is an impact force, and this impact force can cause injury to the player. Therefore, while there are already related designs and technical literature for conventional golf club grips that can absorb this impact force (vibration damping), golf club shafts have lacked such vibration damping functionality. If vibration damping capability could be added to the shaft, the overall vibration damping effect of the golf club, its unique shot feel, and operability could be further improved. In addition, conventional golf club shafts, manufactured from multi-layer carbon fiber prepregs and thermosetting epoxy resin (Thermoset, TS) matrix materials, did not meet environmental protection standards and the materials could not be recycled. Moreover, their elasticity, toughness, and vibration damping capabilities were not ideal, and improvements were desperately needed.

[0008] Therefore, the inventor believed that the above-mentioned shortcomings could be improved, and after diligent consideration, arrived at the proposal of this invention, which effectively improves the above-mentioned problems through a rational design.

[0009] This invention was made in view of the above circumstances, and one of its objectives is to solve the problems described above. Specifically, this invention aims to provide a shaft structure for a golf club. The shaft structure combines the properties of metal, carbon fiber, and plastic materials, and can provide the shaft with suitable elasticity, toughness, flexibility, vibration damping effect, a unique shot feel, and operability. As for the metal material, the sheet is designed to have a thickness of less than 0.2 mm (200 μm; 0.0079 inch), and alternating layers of metal sheets and carbon fiber layers are installed to completely cover the shaft, effectively solving the problem of delamination between different materials due to the extremely large difference in expansion coefficients. In other words, in the golf club shaft according to this invention, a percentage of the carbon fiber material is replaced with metal sheet material in a conventional all-carbon fiber structure, and because the metal sheet (thin metal sheet design) and the thickness of the metal sheet are much thinner than the carbon fiber layer, the change in the expansion coefficient of the total volume of each layer of metal sheet is small. By doing so, the delamination stress generated by volume expansion between the carbon fiber layer and the metal sheet layer is relatively small, and the metal sheet is unable to exert an effective influence on the overall structural stress. This resolves the delamination phenomenon caused by the lack of robustness of the bonding surface due to the extremely large difference in volume expansion coefficients between the carbon fiber layer and the metal layer due to the difference in materials. Furthermore, the shaft of the golf club according to this disclosure is adjusted by adjusting the mixing ratio of carbon fiber and metal material. In other words, because the volume change of the metal sheet material is small, when the coated material is carbon fiber, the delamination stress generated in the metal sheet material is relatively small, and delamination at the contact surface of different materials (carbon fiber material and metal material) is effectively resolved. Conversely, a metal layer that is too thick cannot resolve the serious effects caused by delamination at the contact surface. In addition, the carbon fiber material is completely covered by the metal sheet material, and when subjected to the impact force of a shot, the impact force is absorbed completely and effectively. Therefore, unlike conventional methods where the metal threads are wound spirally, the problem of the force passing through gaps and not being absorbed occurs, making it easier to control long shots and accuracy with a golf club driver.Furthermore, because the aforementioned plastic material employs a thin-film design, its isotropic properties, high vibration damping, and toughness improve upon the shortcomings of unidirectional carbon fiber materials, which can only absorb impact in one direction. This allows for more effective dispersion of the impact force of the shot, providing a comfortable shot feel, vibration damping effect, and improved operability when the golf club shaft grips and hits the driver. [Means for solving the problem]

[0010] To achieve the above objective, a golf club shaft structure according to one aspect of the present invention is characterized in that the shaft structure comprises a carbon fiber layer and at least one layer of plastic film, the carbon fiber layer is at least one layer of carbon fiber prepreg, and is formed by overlapping alternately with the at least one layer of plastic film so as to completely cover it, and all spaces between each material layer are covered with a matrix substrate, and by heat curing.

[0011] In a preferred example of the present invention, the thickness of the carbon fiber layer is greater than the thickness of the plastic film. The matrix substrate is made of a thermosetting epoxy resin (Thermoset, TS) or a thermoplastic (Thermoplastic, TP). The plastic film is made of a plastic material film that can withstand high temperatures, with a melting temperature (Tm) exceeding 150°C.

[0012] In a preferred example of the present invention, the shaft structure further comprises at least one metal layer, the metal layer overlapping alternately with three different materials: the carbon fiber layer and the plastic film, and all spaces between each material layer are covered and in contact with a matrix substrate. Furthermore, if necessary, the alternately overlapping carbon fiber layers and at least one metal sheet are locally punctured by a jig, facilitating exhaust. In addition, the original appearance of the golf club shaft is pre-formed and covered, and then the cross-sectional structure of the entire shaft is formed to resemble the annual rings of a tree, and is formed through heat curing. By bonding different materials, the advantages of each material enhance the unique feel of the golf club shaft, and furthermore, more suitable vibration damping and handling precision effects are achieved.

[0013] In a preferred example of the present invention, the metal layer is a metal sheet, the thickness of the carbon fiber layer is greater than the thickness of the metal sheet, and the metal sheet can be selected from aluminum, aluminum alloy, copper, steel, titanium, titanium alloy, and magnesium-aluminum alloy, with a thickness of less than 0.2 mm (200 μm; 0.0079 inch), and is wrapped around the entire carbon fiber layer and plastic film of the shaft during the heat curing process. In this way, the cross-sectional structure of the entire shaft resembles the annual rings of a tree.

[0014] In a preferred example of the present invention, the thickness of each layer metal sheet is most preferably in the range of 0.004 mm (4 μm; 0.00016 inch) to 0.006 mm (6 μm; 0.00024 inch).

[0015] To solve the above problems, another embodiment of the present invention, a golf club shaft structure, comprises a carbon fiber layer and at least one metal sheet. The carbon fiber layer is at least one carbon fiber prepreg, which overlaps alternately with the at least one metal sheet to completely cover it, and all spaces between the material layers are covered with a matrix substrate. If necessary, the overlapping carbon fiber layers and at least one metal sheet can be locally punctured by a jig to facilitate exhaust. Furthermore, the basic appearance of the golf club shaft is pre-formed and covered, and then the cross-sectional structure of the entire shaft is formed to resemble the annual rings of a tree and undergoes heat curing.

[0016] In a preferred example of the present invention, the thickness of the carbon fiber layer is greater than the thickness of the metal sheet. The matrix substrate is made of a thermosetting epoxy resin (Thermoset, TS) or a thermoplastic (Thermoplastic, TP).

[0017] In a preferred example of the present invention, the metal sheet can be selected from aluminum, aluminum alloy, copper, steel, titanium, titanium alloy, and magnesium-aluminum alloy, and its thickness is less than 0.2 mm (200 μm; 0.0079 inch), and the entire carbon fiber layer and matrix substrate of the shaft are completely covered.

[0018] In a preferred example of the present invention, when the metal sheets are tightly laminated to one another, the thickness of each layer of metal sheet is most preferably in the range of 0.004 mm (4 μm; 0.00016 inch) to 0.006 mm (6 μm; 0.00024 inch).

[0019] To solve the above-mentioned problems and achieve the objective, yet another embodiment of the present invention provides a golf club shaft structure comprising a carbon fiber layer and at least one metal net, wherein the carbon fiber layer is at least one carbon fiber prepreg, which alternately overlaps with the at least one metal net, and all spaces between the material layers are in contact with and covered by thermoplastic (TP), and after being covered, the cross-sectional structure of the entire shaft resembles the annual rings of a tree and is formed by heat curing. When thermoplastic (TP) material is used for the matrix base material, due to the properties of the plastic material itself, it is difficult to adhere to the metal surface to be fixed. Therefore, due to the properties of the metal net, it is heated to a high temperature, completely melted into a liquid state with high viscosity, passes through the gaps in the metal net, and is fixed by being tightly fused to become one with the carbon fiber material.

[0020] The following information will become clear from the description in the specification and drawings described later. [Brief explanation of the drawing]

[0021] [Figure 1] This is a schematic diagram showing how a conventional golf club is constructed by wrapping metal wire around the surface of a carbon fiber material. [Figure 2] This is an external perspective view showing the shaft structure of a golf club and the assembly of the iron head and grip of a golf club according to one embodiment of the present invention. [Figure 2A] This is an external perspective view showing the shaft structure of a golf club and the assembly of the wooden head and grip of a golf club according to one embodiment of the present invention. [Figure 2B] This is an external perspective view showing the shaft structure of a golf club and the assembly of the putter head and grip of a golf club according to one embodiment of the present invention. [Figure 3] This is a cross-sectional view showing the shaft structure of a golf club according to the first embodiment of the present invention. [Figure 4]It is a cross-sectional view showing the shaft structure of a golf club according to a second embodiment of the present invention. [Figure 5] It is a cross-sectional view showing the shaft structure of a golf club according to a third embodiment of the present invention. [Figure 6] It is a cross-sectional view showing the shaft structure of a golf club according to a fourth embodiment of the present invention.

Mode for Carrying Out the Invention

[0022] Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution means of the invention.

[0023] FIG. 2 is an external perspective view showing the assembly of the shaft structure of a golf club, an iron head of a golf club, and a grip according to an embodiment of the present invention. FIG. 2A is an external perspective view showing the assembly of the shaft structure of a golf club, a wood head of a golf club, and a grip according to an embodiment of the present invention. FIG. 2B is an external perspective view showing the assembly of the shaft structure of a golf club, a putter head of a golf club, and a grip according to an embodiment of the present invention.

[0024] As shown in the figure, the golf club 1 has a shaft structure according to the present invention, and referring also to Figure 3 (see the first embodiment of the present invention), the shaft 2 comprises a carbon fiber layer 20 and a plastic film 21, the thickness of the carbon fiber layer 20 being greater than that of the plastic film 21. The carbon fiber layer 20 is formed by winding at least one layer of carbon fiber prepreg in a layered manner and superimposed on the plastic film 21. All spaces between each material layer are in contact with a matrix substrate (not shown), and through the winding process, each carbon fiber layer 20 and the plastic film 21 can be integrally fused, and a complete shaft is formed after heat curing. The aforementioned matrix substrate (Matrix) is made of thermosetting epoxy resin (Thermoset, TS) or thermoplastic (Thermoplastic, TP), and all the spaces between the aforementioned material layers are covered and in contact with the matrix substrate (Matrix). During the winding process, each carbon fiber prepreg is heated and wound to form a carbon fiber layer 20 with high elasticity and toughness, and the plastic film 21 is added during the winding process. The plastic film 21 is made of a heat-resistant plastic material film with a melting temperature (Tm) of over 150°C, such as a PVB film, PEEK plastic material film, PC plastic material film, or PI thermosetting film, and its thickness T1 is less than 0.2 mm (200 μm; 0.0079 inch), most preferably in the range of 0.004 mm (4 μm; 0.00016 inch) to 0.006 mm (6 μm; 0.00024 inch). When the plastic film 21 and the carbon fiber layer 20 of the entire shaft 2 are in contact and heat-cured, the cross-sectional structure of the entire shaft 2 resembles the annual rings of a tree after processing is complete. In this way, the shaft 2 can be given high elasticity, toughness, and excellent vibration damping ability, and the golf club 1 further provides vibration damping ability and a unique shot feel for long-distance drivers.Incidentally, the thermoplastic (TP) matrix substrate is a recyclable material and has high vibration damping, elasticity, and toughness. Therefore, the aforementioned plastic film is not added to the shaft structure of the first embodiment, and only multiple layers of carbon fiber prepreg are alternately stacked, with the thermoplastic (TP) matrix substrate covering all the spaces between the carbon fiber prepreg layers, and the golf club shaft is formed after heat curing. In this way, high elasticity, toughness, and excellent vibration damping ability can be similarly imparted to the golf club, and the golf club further provides vibration damping ability and a unique shot feel to drivers for long distances.

[0025] Figure 4 is a cross-sectional view showing the shaft structure of a golf club according to a second embodiment of the present invention. As shown in the figure, the structure of the shaft 2 according to the second embodiment is substantially the same as that of the first embodiment, and the second embodiment can further improve the overall structural function of the shaft, in addition to having the functions of the structural features of the first embodiment. That is, the shaft 2 according to the second embodiment similarly comprises a carbon fiber layer 20 and a plastic film 21, and further comprises a metal sheet 22, and the carbon fiber layer 20 has at least one layer of carbon fiber prepreg wound in a layered manner. The plastic film 21 is made of a heat-resistant plastic material film with a melting temperature (Tm) of more than 150°C. The metal sheet 22 is selected from aluminum, aluminum alloy, copper, steel, titanium, titanium alloy, and magnesium aluminum alloy, and its thickness T2 is less than 0.2 mm (200 μm; 0.0079 inch), most preferably in the range of 0.004 mm (4 μm; 0.00016 inch) to 0.006 mm (6 μm; 0.00024 inch), and the overall thickness is less than the thickness of the carbon fiber layer 20. All layers of each material are in contact with a matrix substrate (Matrix, not shown), and if necessary, the alternatingly overlapping carbon fiber layers 20 and at least one layer of metal sheet 22 are locally punctured by a jig to facilitate exhaust. Furthermore, after the prototype appearance of the golf club shaft is pre-formed and covered, the overall cross-sectional structure of the shaft resembles the annual rings of a tree, and through the winding process, each carbon fiber layer 20, the plastic film 21, and the metal sheet 22 can be integrally fused together, and after heat curing, a complete shaft 2 is formed. In other words, by designing the metal sheet 22 to be thin T2, the bonding of the surfaces that are joined together between each carbon fiber layer 20 and the metal sheet 22 becomes strong, the delamination stress between layers of different materials does not become maximum, and delamination does not occur at the contact surfaces between each carbon fiber layer 20 and the metal sheet 22, so that the performance is not significantly affected.

[0026] Thus, in addition to the thinning design of the thickness T2 of each metal sheet 22 throughout the shaft 2, the overall thickness becomes less than that of the carbon fiber layer 20. As a result, the volume change of the metal sheet 22 caused by the difference in the coefficients of thermal expansion of the different materials of the carbon fiber layer 20 and the metal sheet 22 is reduced, and the delamination stress generated by the volume change of the carbon fiber layer 20 and the metal sheet 22 is also reduced accordingly. This strengthens the bond between the surfaces of the carbon fiber layer 20 and the metal sheet 22 that are joined together, preventing the delamination stress between different material layers from being maximized. Delamination does not occur at the contact surfaces between the layers of the carbon fiber layer 20 and the metal sheet 22, and thus the delamination between the contact surfaces of different materials is effectively resolved without significantly affecting performance. Conversely, if a metal layer that is too thick is used, it becomes impossible to resolve the significant effects of delamination at the contact surfaces. In this invention, the metal sheet 22 has a reduced thickness T2, and its overall thickness is less than that of the carbon fiber layer 20, thereby providing a strong bond between the surfaces of the carbon fiber layer 20 and the metal sheet 22 that are joined to each other. Thus, in the shaft 2 according to the second embodiment, the carbon fiber layer 20, the plastic film 21, and the metal sheet 22 are alternately overlapped, and all the spaces between each material layer are in contact with and covered by a matrix substrate (Matrix) (TS / TP). After being covered, the cross-sectional structure of the entire shaft resembles the annual rings of a tree, and after heat curing, the shaft 2 can further possess suitable elasticity and toughness, providing precision that facilitates control of long-distance drivers or short-distance putters, and further providing vibration damping capabilities and a unique shot feel.

[0027] Therefore, as can be seen from the description of Figures 3 and 4 above, the structure of the golf club shaft 2 according to the present invention combines the advantages of multiple different materials such as carbon fiber material, plastic material, and metal material, and can impart high elasticity and toughness to the shaft 2, making it easier to control long shots and accuracy with a driver, and further providing vibration damping ability and a unique shot feel to long-distance drivers. In other words, the structure of the golf club shaft 2 according to the present invention is completely covered by the carbon fiber layer 20 and the metal sheet 22, and can provide ease of control of the expected ball rotation after a shot with a putter or driver. In particular, it makes it easier to control the trajectory and rotation stability of a driver, or long shots and accuracy. The plastic film 21 can impart high elasticity, toughness, excellent vibration damping ability, and a unique shot feel to the shaft 2, and the golf club 1 can further provide vibration damping ability to long-distance drivers, and the golf club shaft 2 provides a comfortable and unique shot feel feedback effect when a driver is gripped.

[0028] Furthermore, a metal net is also used in the metal layer of the golf club shaft according to the present invention, and the metal net structure strengthens the adhesive fixing force between the thermoplastic (TP) and carbon fibers on the surface. That is, the shaft structure according to the present invention comprises a carbon fiber layer and at least one metal net, the carbon fiber layer is similarly at least one carbon fiber prepreg, and it overlaps alternately with the at least one metal net, and all the spaces between each material layer are in contact with the thermoplastic (TP) so as to cover them. When a thermoplastic (TP) material is used for the matrix base material, due to the properties of the plastic material itself, it is difficult to bond it to the metal surface so as to fix it in place. In this case, by utilizing the properties of the metal net structure and heating it at a high temperature, the thermoplastic is completely dissolved into a liquid state with high viscosity, passes through the gaps in the metal net, and is fixed so as to be tightly fused and integrated with the carbon fiber material. In this way, it is possible to impart high elasticity and toughness to the shaft, providing vibration damping ability and excellent flexibility.

[0029] Figure 5 is a cross-sectional view showing the shaft structure of a golf club according to a third embodiment of the present invention. Figure 6 is a cross-sectional view showing the shaft structure of a golf club according to a fourth embodiment of the present invention. As shown in Figure 5, the structure of the shaft 2' of the golf club according to the present invention is mainly a variation from the first embodiment in Figure 3, with two or more layers of the plastic film 21' located within the carbon fiber layer 20'. That is, during the winding and heat curing process, the carbon fiber layer 20' is located as the outermost layer of the shaft 2', and its thickness T1 is less than 0.2 mm (200 μm; 0.0079 inch), as in Figure 3, and most preferably in the range of 0.004 mm (4 μm; 0.00016 inch) to 0.006 mm (6 μm; 0.00024 inch). Similarly, as shown in Figure 6, the structure of the golf club shaft 2'' according to the present invention is mainly composed of variations of the different embodiments shown in Figures 3 and 4, with the plastic film 21'' and metal sheet 22'' being placed in the carbon fiber layer 20'' in a multilayer manner, overlapping alternately with gaps between them. The thickness T3 of the metal sheet 22'' is less than 0.2 mm (200 μm; 0.0079 inch), most preferably in the range of 0.004 mm (4 μm; 0.00016 inch) to 0.006 mm (6 μm; 0.00024 inch), and the overall thickness is less than the thickness of the carbon fiber layer 20. That is, during the winding and heat curing process, the plastic film 21'' and metal sheet 22'' are continuously wound, and the carbon fiber layer 20'' is located as the outermost layer of the shaft 2''. Thus, the transverse cross-sectional structure in Figures 5 and 6 can be made to more closely resemble the annual rings of a tree, and the thin design of the metal sheet 22'' with a thickness T3 results in a stronger bond between the surfaces joined to each other between each carbon fiber layer 20'' and the metal sheet 22'', preventing the delamination stress between different materials from being maximized, and preventing delamination from occurring at the contact surfaces between the layers of each carbon fiber layer 20'' and the metal sheet 22'', thus not significantly affecting performance.Therefore, it is possible to impart high elasticity and toughness to all shafts 2' and 2'', further providing vibration damping ability and a unique shot feel. When a driver is gripped by the shaft 2'' of the golf club, it provides comfortable shot feel feedback, vibration damping effect, and improved operability.

[0030] In summary, the above explanation is intended to describe the present invention and should not be interpreted as limiting or restricting the scope of the invention described in the claims for utility model registration. Furthermore, it goes without saying that the configuration of each part of the present invention is not limited to the above embodiments and can be modified in various ways within the technical scope described in the claims for utility model registration. [Explanation of Symbols]

[0031] 1 Golf Club 2 shafts 2' shaft 2'' shaft 20 Carbon fiber layer 20' carbon fiber layer 20'' carbon fiber layer 21 Plastic film 21' Plastic film 21'' Plastic film 22 Metal sheet 22' Metal Sheet 22'' Metal Sheet T1 Plastic film thickness T2 Metal sheet thickness T3 metal sheet thickness

Claims

1. A golf club shaft structure comprising a carbon fiber layer and at least one layer of plastic film, wherein the carbon fiber layer is at least one layer of carbon fiber prepreg, and is alternately overlapped with the at least one layer of plastic film so as to completely cover it, and all spaces between each material layer are in contact with a matrix substrate so as to cover it, and after being covered, the cross-sectional structure of the entire shaft resembles the annual rings of a tree and is formed by heat curing.

2. The shaft structure of a golf club according to claim 1, characterized in that the thickness of the carbon fiber layer is greater than that of the plastic film.

3. The golf club shaft structure according to claim 2, characterized in that the plastic film is made of a plastic material film that can withstand high temperatures with a melting point exceeding 150°C.

4. The shaft structure of a golf club according to claim 3, characterized in that the matrix substrate is made of a thermosetting epoxy resin or a thermoplastic.

5. The shaft structure of a golf club according to claim 4, further comprising at least one metal layer, wherein the metal layer overlaps alternately with the carbon fiber layer and the plastic film so as to cover the entire surface, and all spaces between each material layer are in contact with a matrix substrate so as to cover and, after being covered, the cross-sectional structure of the entire shaft resembles the annual rings of a tree and is formed by heat curing.

6. The golf club shaft structure according to claim 4, characterized in that the thickness of the plastic film is less than 0.2 mm, the entire carbon fiber layer of the shaft is completely covered, and after covering, the cross-sectional structure of the entire shaft resembles the annual rings of a tree.

7. The golf club shaft structure according to claim 6, characterized in that the thickness of each layer of plastic film is most preferably in the range of 0.004 mm to 0.006 mm.

8. The metal layer is made of a metal sheet, one of which can be selected from aluminum, aluminum alloy, copper, steel, titanium, titanium alloy, and magnesium aluminum alloy, and its thickness is less than 0.2 mm, and the entire carbon fiber layer and plastic film of the shaft are completely covered, and after being covered, the cross-sectional structure of the entire shaft resembles the annual rings of a tree, as described in claim 5.

9. The shaft structure of a golf club according to claim 8, characterized in that the thickness of the carbon fiber layer is greater than that of the metal sheet.

10. The golf club shaft structure according to claim 7, characterized in that the thickness of each layer metal sheet is most preferably in the range of 0.004 mm to 0.006 mm.

11. The metal layer is made of a metal net that overlaps alternately with the carbon fiber layer and the plastic film so as to completely cover it, and the three layers are interconnected with a prepreg substrate and then heat-cured to form the shaft of the golf club, and after molding, the cross-sectional structure of the entire shaft of the golf club resembles the annual rings of a tree, as described in claim 5.

12. A golf club shaft structure, wherein the shaft structure is composed of alternating layers of carbon fiber and at least one metal sheet, the carbon fiber layer being at least one carbon fiber prepreg, alternating with at least one metal sheet having a thickness of less than 0.2 mm so as to completely cover it, and all spaces between each material layer are in contact with a matrix substrate so as to cover it, and after being covered, the cross-sectional structure of the entire shaft resembles the annual rings of a tree and is formed by heat curing.

13. The shaft structure of a golf club according to claim 12, characterized in that the thickness of the carbon fiber layer is greater than that of the metal sheet.

14. The shaft structure of a golf club according to claim 13, characterized in that the matrix substrate is made of a thermosetting epoxy resin or a thermoplastic.

15. The shaft structure of a golf club according to claim 14, characterized in that the metal sheet can be selected from aluminum, aluminum alloy, copper, steel, titanium, titanium alloy, and magnesium aluminum alloy, and the entire carbon fiber layer of the shaft is completely covered, and after being covered, the cross-sectional structure of the entire shaft resembles the annual rings of a tree.

16. The golf club shaft structure according to claim 12, characterized in that the thickness of each layer of metal sheet is most preferably in the range of 0.004 mm to 0.006 mm.

17. A golf club shaft structure, wherein the shaft structure comprises a carbon fiber layer and at least one metal net, the carbon fiber layer being at least one carbon fiber prepreg, overlapping alternately with the at least one metal net, and all spaces between the material layers being in contact with and covered by thermoplastic plastic, and after being covered, the cross-sectional structure of the entire shaft is similar to the annual rings of a tree and is formed by heat curing.

18. A golf club shaft structure, wherein the shaft structure is composed of carbon fiber layers, and the carbon fiber layers are formed by alternating overlapping of at least one layer of carbon fiber prepreg, with all spaces between the carbon fiber prepreg layers being covered and in contact with a thermoplastic matrix substrate, and formed by heat curing.

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