JP5729939B2 - Golf club - Google Patents

Description

  The present invention relates to a golf club. Specifically, the present invention relates to a golf club in which a head and a shaft can be attached and detached.

  A golf club in which the head and the shaft can be attached and detached has been proposed. The ease of attaching and detaching the head and shaft is beneficial for several reasons. If it is easy to attach and detach, the golfer can easily change the head and shaft. For example, it becomes easy for a golfer who is not satisfied with the performance of a purchased golf club to change the head and shaft himself. In addition, the golfer himself can easily assemble an original golf club in which a favorite head and a favorite shaft are combined. Golfers can purchase their favorite heads and favorite shafts and assemble them themselves. In addition, a golf club store can select and sell a combination of a head and a shaft that is appropriate for the golfer. The easily removable head and shaft facilitate custom-made golf clubs.

  JP-T-2008-520274, JP-T-2005-533626, and JP-A-2006-42951 disclose structures in which the head and the shaft are easily attached and detached.

  Furthermore, golf clubs in which an inclination angle θ1 is provided between the shaft axis and the hosel axis in a mechanism for attaching and detaching the head and the shaft are disclosed in JP 2000-5349 A, JP 2005-270402 A, and WO 2009/009291. (PCT application). In these inventions, the loft angle, lie angle, and hook angle (face angle) can be adjusted according to the circumferential position of the shaft.

  On the other hand, a shaft having a property of causing twisting in conjunction with bending (bending) has been proposed. This property is also referred to as “anisotropic” in the present application, and a shaft having this anisotropy is also referred to as “anisotropic shaft”. This anisotropic shaft is disclosed in JP-A-3-227616, JP-A-11-76480, JP-A-11-299944, and JP-A-2003-265661. These anisotropic shafts can correct hooks and slices.

Special table 2008-520274 gazette JP-T-2005-533626 JP 2006-42951 A JP 2000-5349 A JP 2005-270402 A WO2009 / 009291 JP-A-3-227616 Japanese Patent Laid-Open No. 11-76480 JP-A-11-299944 JP 2003-265661 A

  In the golf club having the inclination angle θ1, the angle adjustment corresponding to the golfer can be performed by changing the circumferential position of the shaft. For example, the hook angle (face angle) can be adjusted. However, when the tilt angle θ1 is large, a strange feeling is likely to occur in appearance. Due to this discomfort, the golfer may find it difficult to hold. This sense of incongruity and difficulty in holding can hinder a smooth swing.

  On the other hand, since the anisotropic shaft is the same as a normal shaft in appearance, it does not cause a sense of incongruity. However, in the manufacture of the shaft using the anisotropically-expressing sheet, labor is required for cutting and bonding the prepreg, and the work process is increased. Moreover, when the width | variety of an anisotropic expression sheet | seat is narrow, the continuity of a fiber will be lost and the twist strength and bending strength of a shaft will fall easily. As will be described later, the anisotropic expression sheet is usually used together with a hoop layer sheet. This hoop layer sheet is relatively expensive.

  In order to increase the effect of correcting hooks and slices, it is necessary to arrange many anisotropically developed sheets in the shaft. However, when there are many anisotropic expression sheets, intensity | strength falls easily and the manufacturing process of a shaft becomes complicated. A shaft using many anisotropically developed sheets has low productivity and high manufacturing cost. On the other hand, when there are few anisotropic expression sheets, the amount of bending twist tends to fall. When the amount of bending twist is small, the effect of correcting hooks and slices decreases.

  An object of the present invention is to provide a golf club capable of various adjustments and capable of suppressing a sense of incongruity at the time of addressing.

  The golf club of the present invention can attach and detach the head 4 having a hosel hole, the shaft 6, the sleeve 8 positioned between the hosel hole 18 and the shaft 6, and the head 4 and the sleeve 8. And an attaching / detaching mechanism. The attachment / detachment mechanism can fix the shaft 6 to the hosel hole 18 of the head 4 at a plurality of sleeve positions. The axis of the shaft 6 is inclined with respect to the axis of the hosel hole 18 at an inclination angle θ1. The shaft 6 has anisotropy in which twisting occurs in conjunction with bending.

  Preferably, the inclination angle θ1 is not less than 0.2 ° and not more than 1.0 °.

  Preferably, the attachment / detachment mechanism includes a sleeve 8 fixed to a tip portion of the shaft 6, a rotation preventing portion that restricts relative rotation between the sleeve 8 and the hosel hole 18, and the sleeve 8 and the hosel hole 18. And a slip-out preventing portion for restricting relative movement in the axial direction. Preferably, the rotation preventing portion and the slipping preventing portion can be fixed at a plurality of the sleeve positions.

  Preferably, the amount of bending twist of the shaft is not less than 0.5 ° and not more than 3.0 °.

Preferably, the sleeve is fixed to the shaft to form a shaft-sleeve assembly. Preferably, in the shaft-sleeve assembly, the circumferential relative position between the shaft and the sleeve is set so that the next club position a1 is possible.
[Club position a1]: In the sleeve position where the hook angle is maximized, the shaft position is positioned so that the head is twisted in the closing direction due to the bending in the toe-down direction.

Preferably, the sleeve is fixed to the shaft to form a shaft-sleeve assembly. Preferably, in the shaft-sleeve assembly, the circumferential relative position between the shaft and the sleeve is set so that the next club position b1 is possible.
[Club position b1]: At the sleeve position where the hook angle is the minimum, the shaft position is positioned so that the head is twisted in the opening direction due to bending in the toe-down direction.

  A golf club that can be adjusted in various ways with little discomfort at the time of addressing can be obtained.

FIG. 1 is a view showing a golf club according to an embodiment of the present invention. FIG. 2 is an exploded view of FIG. 3 is a cross-sectional view of the head of FIG. 1 in the vicinity of the hosel. FIG. 4 is a perspective view showing an example of a sleeve. FIG. 5 is a bottom view of the sleeve of FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 9 is a cross-sectional view taken along line F9-F9 in FIG. FIG. 10 is a development view showing an example of a prepreg configuration of the shaft according to the present invention. FIG. 11 is a diagram illustrating a state in which the anisotropic expression sheet is bonded to the hoop layer sheet. FIG. 12 is a development view showing another example of the prepreg configuration of the shaft according to the present invention. FIG. 13 is a diagram illustrating a state in which the anisotropic expression sheet is bonded to the hoop layer sheet. FIG. 14 is a conceptual diagram showing the arrangement of the anisotropically developed sheet in the circumferential direction. FIG. 15 is a development view showing another example of the prepreg configuration of the shaft according to the present invention. FIG. 16 is a diagram for explaining the shaft position and the sleeve position. FIG. 17 is a diagram for explaining a method of measuring the amount of bending twist. FIG. 18 is a diagram for explaining a method of measuring the amount of bending twist. FIG. 19 is a graph showing the relationship between the bending direction and the twist angle.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  FIG. 1 shows a golf club 2 according to an embodiment of the present invention. FIG. 1 shows only the vicinity of the head of the golf club 2. FIG. 2 is an exploded view of the golf club 2. FIG. 3 is a cross-sectional view of the golf club 2. FIG. 3 is a sectional view taken along the central axis of the sleeve 8.

  The golf club 2 has a head 4, a shaft 6, a sleeve 8, a screw 10 and a ferrule 12. A sleeve 8 is fixed to the tip of the shaft 6. A grip (not shown) is attached to the rear end of the shaft 6.

  The head 4 has a head main body 14 and an engaging member 16. The head main body 14 has a hosel hole 18 for inserting the sleeve 8 and a through hole 19 for inserting the screw 10 (see FIG. 3). The through hole 19 passes through the bottom of the hosel hole 18. The head body 14 has a sole hole 20 that opens to the sole (see FIG. 3). The sole hole 20 and the hosel hole 18 are continuous by the through hole 19. The head body 14 has a hollow portion.

  The type of the head 4 is not limited. The head 4 of this embodiment is a wood type golf club. The head 4 may be a hybrid head, a utility head, an iron head, a putter head, or the like.

  The shaft 6 is preferably a carbon shaft.

  The screw 10 has a head portion 22 and a shaft portion 24 (see FIG. 2). The screw 10 passes from the sole hole 20 through the through hole 19 and reaches a screw hole 32 (described later). The shaft portion 24 is screwed to the sleeve 8 (details will be described later). The head 22 has a wrench recess 26 (see FIG. 3). By using a wrench (such as a hexagon wrench or a dedicated wrench) suitable for the recess 26, the screw 10 positioned inside the head main body 14 can be pivoted. The screw mechanism using the screw 10 enables the sleeve 8 to be attached and detached.

  The engaging member 16 is fixed to the head body 14 (see FIG. 3). The fixing method is not limited, and examples thereof include adhesion, welding, fitting, and a combination thereof. The engaging member 16 is inserted into the hosel hole 18 from the upper opening of the hosel hole 18. The engaging member 16 is fixed to the bottom of the hosel hole 18.

  The engaging member 16 has a rotation preventing part. The rotation preventing portion is formed on the inner surface of the engagement member 16. This rotation prevention unit will be described later.

  FIG. 4 is a perspective view of the sleeve 8. FIG. 5 is a bottom view of the sleeve 8. 6 is a cross-sectional view taken along line VI-VI in FIG. 7 is a cross-sectional view taken along line VII-VII in FIG.

  8 is a cross-sectional view taken along line VIII-VIII in FIG. FIG. 8 and FIG. 6 are in a horizontally reversed relationship with each other.

  The sleeve 8 has a shaft hole 30 and a screw hole 32 (FIGS. 6 and 7). The shaft hole 30 is open to one side (upper side). The screw hole 32 opens to the other side (lower side). A screw hole 32 is disposed below the shaft hole 30.

  Furthermore, the sleeve 8 has a constant diameter circumferential surface 34, an inclined surface 35, an exposed surface 36, and a rotation preventing portion 38. The constant diameter circumferential surface 34 is a portion having a constant outer diameter. A stepped surface 39 exists at the lower end of the exposed surface 36.

  In the shaft mounted state (see FIGS. 1 and 3), the exposed surface 36 is exposed to the outside. The outer diameter of the lower end of the exposed surface 36 is substantially equal to the outer diameter of the hosel end surface 37. The outer diameter of the upper end of the exposed surface 36 is substantially equal to the outer diameter of the lower end of the ferrule 12. The exposed surface 36 and the ferrule 12 as a whole look like a conventional ferrule. The exposed surface 36 improves the appearance.

  A portion of the sleeve 8 below the exposed surface 36 is inserted into the hosel hole 18 (see FIG. 3). The shape of the inclined surface 35 corresponds to the shape of the chamfered portion 41 of the hosel hole 18 (see FIG. 3).

  As shown in FIG. 6, the axis h1 of the shaft hole 30 is inclined with respect to the axis z1 of the outer surface of the sleeve. The inclination angle θ1 is the maximum value of the angle formed by the axis h1 and the axis z1. The axis line z1 coincides with the central axis line of the constant-diameter circumferential surface 34. The axis line z1 is substantially equal to the axis line of the hosel hole 18. The axis h1 of the shaft hole 30 is substantially equal to the axis s1 of the shaft 6.

  The shaft 6 is fixed to the shaft hole 30. This fixing is achieved by bonding with an adhesive. The outer surface of the shaft 6 is bonded to the inner surface of the shaft hole 30. It may be fixed by means other than adhesion.

  Preventing the sleeve 8 from coming off is achieved by screw connection. As shown in FIG. 3, the screw hole 32 of the sleeve 8 is screwed to the screw 10. This screw connection prevents the sleeve 8 from coming off. The axial force resulting from this screw connection is balanced with the pressure between the hosel end surface 37 and the step surface 39. In order to secure this axial force, a gap K1 exists between the tip of the screw 10 and the bottom surface of the screw hole 32 in the state where the screw coupling is completed (see FIG. 3). In addition, a gap K2 exists between the bottom surface 43 of the sleeve 8 and the head body 14 in the state where the screw connection is completed (see FIG. 3).

  As shown in FIG. 4, the rotation preventing portion 38 of the sleeve 8 has twelve convex portions t2. The convex parts t2 are evenly arranged in the circumferential direction. The convex part t2 is arrange | positioned every fixed angle (30 degrees).

  The rotation preventing unit 38 has rotational symmetry with the axis line z1 as a rotational symmetry axis. Rotational symmetry means that the shape before rotation is coincident when rotated (360 / W) degrees around the rotational symmetry axis. However, W is an integer of 2 or more. Matching with the shape before the rotation when rotating about the rotational symmetry axis (360 / W) is also referred to as “W-fold rotational symmetry”. The rotation preventing unit 38 is 12 times rotationally symmetric with respect to the axis line z1.

  9 is a cross-sectional view taken along line F9-F9 in FIG.

  The outer surface of the engaging member 16 is a circumferential surface having a constant outer diameter. On the other hand, an anti-rotation portion 48 is provided inside the engagement member 16. The rotation preventing part 48 is formed by twelve concave parts r2. These recesses r2 are arranged at equal intervals in the circumferential direction. The engaging member 16 may be integrally formed with the head body 14.

  The rotation prevention unit 48 has rotational symmetry with the axis line z1 as a rotational symmetry axis. The rotation prevention unit 48 is 12-fold rotationally symmetric with respect to the axis line z1. The shape of the rotation prevention unit 48 corresponds to the shape of the rotation prevention unit 38.

  The engaging member 16 separated from the head main body 14 is easily molded with high accuracy. For example, the engaging member 16 that is a separate body from the head main body 14 is easily cut. Since the engaging member 16 is separated from the head main body 14, the dimensional accuracy of the rotation preventing portion 48 of the engaging member 16 can be improved.

  The rotation prevention of the sleeve 8 is achieved by the engagement between the rotation preventing portion 38 and the rotation preventing portion 48. The rotation prevention unit 38 and the rotation prevention unit 48 are engaged so as to restrict relative rotation between the head 4 and the shaft 6.

  There are 12 circumferential relative positions at which the rotation preventing portion 38 and the rotation preventing portion 48 can be engaged. When the circumferential relative position is changed, the loft angle, the lie angle, and the hook angle can be changed. These changes in angle are caused by the inclination angle θ1 described above. In the present embodiment, the loft angle, the lie angle, and the hook angle can be adjusted due to the 12 circumferential relative positions. Loft angle, lie angle and hook angle suitable for each golfer can be selected.

  The number of the relative positions in the circumferential direction that can be engaged is not limited to twelve, but four, five, six, eight, sixteen, twenty-four, and the like are exemplified.

  The inclination angle θ1 is not limited. When the inclination angle θ1 is excessive, an uncomfortable appearance is likely to occur and is difficult to hold. Such a sense of incongruity and difficulty in holding can inhibit a smooth swing. From the viewpoint of suppressing the uncomfortable feeling and difficulty in holding, the inclination angle θ1 is preferably 1.0 ° or less, more preferably 0.9 ° or less, and particularly preferably 0.8 ° or less. From the viewpoint of increasing the degree of freedom in adjusting the hook angle, loft angle, and lie angle and improving the hitting direction, the inclination angle θ1 is preferably 0.2 ° or more, more preferably 0.3 ° or more, and 0.4 °. The above is particularly preferable.

  In a general golf club, when the shaft is removed from the head, the adhesive bonding the two is destroyed by heating. However, in this golf club 2, the head body 14 and the shaft 6 can be attached and detached without breaking the adhesive.

  In the present invention, the shaft 6 has anisotropy. In the present application, “anisotropic” means a property in which twisting occurs in conjunction with bending (bending). The manufacturing method and structure of the shaft having this anisotropy are described in, for example, the above-mentioned Japanese Patent Application Laid-Open No. 11-299944 or Japanese Patent Application Laid-Open No. 2003-265661. The shaft 6 of the present application can also be manufactured by the manufacturing method described in these publications.

  FIG. 10 is a development view showing an example (first laminated structure) of the laminated structure of the shaft 6 that can be used in the present invention.

  The shaft 6 is manufactured by a so-called sheet winding method. In manufacturing the shaft 6, first, the prepreg is cut to prepare the prepreg sheet shown in FIG. The angle described in FIG. 10 indicates the fiber orientation angle Ag with respect to the longitudinal direction of the shaft. In the embodiment of FIG. 10, 21 sheets are used.

  Next, a bonding process is performed. FIG. 11 shows the united sheet obtained by the bonding process.

  In this bonding step, the sheet s3 and the sheet s4 are bonded to the sheet s5 to obtain a combined sheet bs3. Similarly, the sheet s6 and the sheet s7 are bonded to the sheet s8 to obtain a combined sheet bs6. Similarly, the sheet s9 and the sheet s10 are bonded to the sheet s11 to obtain a combined sheet bs9. Similarly, the sheet s12 and the sheet s13 are bonded to the sheet s14 to obtain a combined sheet bs12. Similarly, the sheet s15 and the sheet s16 are bonded to the sheet s17 to obtain a combined sheet bs15.

  The bias sheet s3 alone is difficult to wind. Similarly, the bias sheet s4 is difficult to wind alone. It is because it is easy to tear along the fiber direction when wound alone. Therefore, these are attached to the sheet s5 which is a hoop layer sheet, and are wound as a united sheet bs3. As shown in FIG. 11, the sheet s3 and the sheet s4 are arranged on the sheet s5 with no gap therebetween and are bonded together. The contour shape of the sheet s5 substantially matches the contour shape obtained by arranging the sheet s3 and the sheet s4 without gaps. The fiber orientation of the sheet s3 and the fiber orientation of the sheet s4 are opposite to each other. This united sheet bs3 is subjected to a winding process.

  The bias sheet s6 is difficult to wind alone. Similarly, the bias sheet s7 is difficult to wind alone. These are affixed on the sheet | seat s8 which is a sheet | seat for hoop layers, and are wound as the united sheet | seat bs6. As shown in FIG. 11, on the sheet s8, the sheet s6 and the sheet s7 are arranged with no gap and bonded together. The contour shape of the sheet s8 substantially matches the contour shape obtained by arranging the sheet s6 and the sheet s7 without gaps. The fiber orientation of the sheet s6 and the fiber orientation of the sheet s7 are opposite to each other. This united sheet bs6 is subjected to a winding process.

  The bias sheet s9 is difficult to wind alone. Similarly, the bias sheet s10 is difficult to wind alone. These are affixed on the sheet s11 which is a hoop layer sheet, and are wound as a united sheet bs9. As shown in FIG. 11, on the sheet s11, the sheet s9 and the sheet s10 are arranged with no gap and bonded together. The contour shape of the sheet s11 substantially matches the contour shape obtained by arranging the sheet s9 and the sheet s10 without gaps. The fiber orientation of the sheet s9 and the fiber orientation of the sheet s10 are opposite to each other. This united sheet bs9 is subjected to a winding process.

  The bias sheet s12 is difficult to wind alone. Similarly, the bias sheet s13 is difficult to wind alone. These are affixed on the sheet s14 which is a hoop layer sheet, and are wound as a united sheet bs12. As shown in FIG. 11, the sheet s12 and the sheet s13 are arranged on the sheet s14 without any gap and are bonded together. The contour shape of the sheet s14 substantially matches the contour shape obtained by arranging the sheet s12 and the sheet s13 without gaps. The fiber orientation of the sheet s12 and the fiber orientation of the sheet s13 are opposite to each other. This united sheet bs12 is subjected to a winding process.

  The bias sheet s15 is difficult to wind alone. Similarly, the bias sheet s16 is difficult to wind alone. These are attached to the sheet s17 which is a hoop layer sheet, and are wound as a united sheet bs15. As shown in FIG. 11, on the sheet s17, the sheet s15 and the sheet s16 are arranged with no gap therebetween and bonded together. The contour shape of the sheet s17 substantially matches the contour shape obtained by arranging the sheet s15 and the sheet s16 without gaps. The fiber orientation of the sheet s15 and the fiber orientation of the sheet s16 are opposite to each other. This united sheet bs15 is subjected to a winding process.

  The united sheet bs3, united sheet bs6, united sheet bs9, united sheet bs12, and united sheet bs15 are the same except for a slight difference in dimensions.

  Next, a winding process is performed. In this winding step, the sheets are wound around the mandrel in the order shown in FIG. The sheet shown on the upper side in FIG. 10 is wound earlier.

  Next, the wrapping tape is wound. Next, a heating process is performed. A heating furnace is used for the heating step. By this heating step, the matrix resin of the prepreg is cured. Next, the wrapping tape is removed and the mandrel is pulled out. Next, the front end and the rear end are cut. Next, surface polishing is performed. Finally, painting is done.

  In the winding step, the united sheet bs3, the united sheet bs6, the united sheet bs9, the united sheet bs12, and the united sheet bs15 are wound from the same circumferential position.

  The number of windings of the sheet s3 is 0.5 ply. That is, the installation range in the circumferential direction of the sheet s3 is about 180 °. The number of windings of the sheet s4 is 0.5 ply. The number of windings of the sheet s6 is 0.5 ply. The number of windings of the sheet s7 is 0.5 ply. The number of windings of the sheet s9 is 0.5 ply. The number of windings of the sheet s10 is 0.5 ply. The number of windings of the sheet s12 is 0.5 ply. The number of windings of the sheet s13 is 0.5 ply. The number of windings of the sheet s15 is 0.5 ply. The number of windings of the sheet s16 is 0.5 ply. The reason why these are set to 0.5 ply is to efficiently develop anisotropy.

  In the sheet configuration of FIG. 10, the first group of sheets including the sheet s3, the sheet s6, the sheet s9, the sheet s12, and the sheet s15 are arranged at the same circumferential position. On the other hand, the second group of sheets including the sheet s4, the sheet s7, the sheet s10, the sheet s13, and the sheet s16 are arranged at the same circumferential position. In the sheets belonging to the first group, the fiber orientation is the same. In the sheets belonging to the second group, the fiber orientation is the same. The orientation of the fibers of the sheet belonging to the first group and the orientation of the fibers of the sheet belonging to the second group are opposite to each other. The first group of sheets and the second group of sheets are arranged at different circumferential positions. If the first group of sheets is arranged at a circumferential position of 0 ° to 180 °, the second group of sheets is arranged at a circumferential position of 180 ° to 360 °. In this configuration, the inclination direction of the bias layer is opposite every other half circumference. This configuration contributes to the efficient expression of anisotropy. This configuration contributes to an increase in the amount of bending twist.

  FIG. 12 is a development view showing another example (second laminated structure) of the laminated structure of the shaft 6. In the embodiment of FIG. 12, 14 sheets are used.

  In the embodiment of FIG. 12, the number of sheets that exhibit anisotropy (hereinafter also referred to as an anisotropic expression sheet) is smaller than in the embodiment of FIG. In the embodiment shown in FIG. 12, the number of hoop layer sheets is small as compared with the embodiment shown in FIG. In the embodiment of FIG. 12, the steps for cutting the prepreg and the bonding step are fewer as compared with the embodiment of FIG. Therefore, the embodiment of FIG. 12 is excellent in productivity and can reduce the manufacturing cost.

  Also in this embodiment, a 0.5 ply anisotropic expression sheet is used. Also in this embodiment, the anisotropic expression layer is wound in a state of being attached to the prepreg for the hoop layer. FIG. 13 shows a united sheet obtained by the bonding process.

  Also in this embodiment, the bonding step is performed after the step of cutting the prepreg. In this bonding step, the sheet t5 and the sheet t6 are bonded to the sheet t7 to obtain a combined sheet bt5. Similarly, the sheet t8 and the sheet t9 are bonded to the sheet t10 to obtain a combined sheet bt8.

  In this embodiment, anisotropic expression sheets t3 and t4 are used. In the bonding step, the sheet t3 and the sheet t4 are bonded together. The sheet t4 is bonded to the sheet t3 while being turned over. Therefore, the sheet t3 and the sheet t4 are opposite to each other in the orientation angle Ag. That is, when the orientation angle Ag of the sheet t3 is −30 °, the orientation angle Ag of the sheet t4 is + 30 °. In FIG. 12, the sheet t4 is illustrated in a state where it is not turned over.

  The winding start position of the sheet t3 is different from the winding start position of the sheet t4 by about 180 °. Bonding is performed so that the difference in winding start position is approximately 180 °.

  The number of plies (number of windings) of the sheet t3 is 1.5. In the sheet t3, 0.5 plies out of 1.5 plies function as an anisotropic expression part. This anisotropic expression part is arrange | positioned in the same circumferential direction position as the 1st group mentioned later.

  The number of plies (number of windings) of the sheet t4 is also 1.5. In the sheet t4, 0.5 plies out of 1.5 plies function as an anisotropic expression part. This anisotropic expression part is arrange | positioned in the same circumferential direction position as the 2nd group mentioned later.

  Since the sheet t3 and the sheet t4 are 1.5 plies, the fibers are longer in the circumferential direction than the 0.5 ply anisotropic sheet. The sheet t3 and the sheet t4 contribute to torsional strength, bending strength, and torsional rigidity. The sheet t3 and the sheet t4 can improve strength while exhibiting anisotropy.

  In the winding process, the sheets are wound around the mandrel in the order shown in FIG. The sheets are sequentially wound from the sheet shown on the upper side in FIG. In this winding step, the united sheet bt5 and the united sheet bt8 are wound from the same circumferential position.

  Except for the sheet t3 and the sheet t4, the arrangement of the anisotropically-expressing sheet is similar to the first laminated structure. That is, the first group including the sheet t5 and the sheet t8 is arranged at the same circumferential position. The second group consisting of the sheet t6 and the sheet t9 is arranged at the same circumferential position. The first group of sheets and the second group of sheets are arranged at different circumferential positions. If the first group of sheets is arranged at a circumferential position of 0 ° to 180 °, the second group of sheets is arranged at a circumferential position of 180 ° to 360 °. In this configuration, the fiber orientation angle Ag is reversed every other half circumference. This configuration contributes to the efficient expression of anisotropy. This configuration contributes to an increase in the amount of bending twist.

  FIG. 14 is a conceptual diagram showing the arrangement in the circumferential direction of the anisotropically-expressing sheet in the shaft having the sheet configuration of FIG. In FIG. 14, the edge of the sheet is displayed in a round shape. In this configuration, the first group of anisotropically developed sheets (sheet t5 and sheet t8) are arranged at circumferential positions from 0 ° to 180 °, and the second group of anisotropically developed sheets (sheet t6 and sheet t9). ) Are arranged at circumferential positions from 180 ° to 360 °. Between the first group of anisotropic expression sheets and the second group of anisotropic expression sheets, the fiber orientation is reversed. This configuration is set over the entire longitudinal direction of the shaft.

  An anisotropic expression part t31 of the sheet t3 is indicated by a bold line in FIG. The anisotropic expression part t31 is disposed at the same circumferential position as the first group of anisotropic expression sheets. The anisotropic expression part t31 contributes to an increase in the amount of bending twist.

  An anisotropic expression portion t41 of the sheet t4 is indicated by a bold line in FIG. The anisotropic expression part t41 is arranged at the same circumferential position as the second group of anisotropic expression sheets. The anisotropic expression part t41 contributes to an increase in the amount of bending twist.

  FIG. 15 is a development view showing another example (third laminated structure) of the laminated structure of the shaft 6. In the embodiment of FIG. 15, 11 sheets are used.

  In the embodiment of FIG. 15, the number of sheets that exhibit anisotropy (hereinafter also referred to as an anisotropic expression sheet) is smaller than that of the embodiment of FIG. 12. The embodiment of FIG. 15 is excellent in productivity and can reduce the manufacturing cost.

  In this embodiment, a 0.5 ply anisotropic expression sheet is not used. In this embodiment, there is no hoop layer to be bonded to the anisotropic expression sheet. In this embodiment, there is little effort of bonding. Furthermore, in this embodiment, the use of a hoop layer is suppressed.

  Also in this embodiment, the bonding step is performed after the step of cutting the prepreg. In this bonding step, the sheet r4 is bonded to the sheet r3 to obtain a combined sheet (not shown). Similarly, the sheet r6 is bonded to the sheet r5 to obtain a combined sheet.

  The sheet r4 is bonded to the sheet r3 while being turned over. Therefore, the sheet r3 and the sheet r4 have the opposite orientation angles Ag. That is, when the orientation angle Ag of the sheet r3 is −30 °, the orientation angle Ag of the sheet r4 is + 30 °. In FIG. 15, the sheet r4 is shown in a state where it is not turned over. Similarly, the sheet r6 is bonded to the sheet r5 while being turned over.

  The winding start position of the sheet r3 is different from the winding start position of the sheet r4 by about 180 °. Bonding is performed so that the difference in winding start position is approximately 180 °. Similarly, the winding start position of the sheet r5 is different from the winding start position of the sheet r6 by about 180 °. Bonding is performed so that the difference in winding start position is approximately 180 °.

  The number of plies (the number of windings) of the sheet r3 is 1.5. In the sheet r3, 0.5 plies out of 1.5 plies function as an anisotropic expression part. The number of plies (number of windings) of the sheet r4 is also 1.5. In the sheet r4, 0.5 plies out of 1.5 plies function as an anisotropic expression part.

  The number of plies (number of windings) of the sheet r5 is 1.5. In the sheet r5, 0.5 plies out of 1.5 plies function as an anisotropic expression part. The number of plies (number of windings) of the sheet r6 is also 1.5. In the sheet r6, 0.5 plies out of 1.5 plies function as an anisotropic expression part.

  The circumferential position (position P1) is the same in the anisotropy developing portion of the sheet r3 and the anisotropy developing portion of the sheet r5. These form a plurality of anisotropic expression layers. The plurality of anisotropic expression layers contributes to an increase in the amount of bending twist.

  The circumferential position (position P2) is the same in the anisotropy developing portion of the sheet r4 and the anisotropy developing portion of the sheet r6. These form a plurality of anisotropic expression layers. The plurality of anisotropic expression layers contributes to an increase in the amount of bending twist.

  The position P1 and the position P2 are arranged at circumferential positions that are 180 degrees different from each other. With this configuration, the amount of bending twist is improved.

  Since the sheet r3 and the sheet r4 are 1.5 plies, the fibers are longer in the circumferential direction than the 0.5 ply anisotropic sheet. The sheet r3 and the sheet r4 contribute to torsional strength, bending strength, and torsional rigidity. The sheets r3 and r4 can improve strength while exhibiting anisotropy. Similarly, the sheet r5 and the sheet r6 can improve strength while exhibiting anisotropy.

  In addition to the sheet configuration described above, for example, the sheet configuration described in Japanese Patent Laid-Open No. 11-299944 or Japanese Patent Laid-Open No. 2003-265661 described above may be employed.

FIG. 16 is a diagram for explaining the relationship among the head 4, the shaft 6, and the sleeve 8. The twist angle of the anisotropic shaft differs depending on the direction of bending. Further, since the sleeve 8 has the inclination angle θ1, the direction of the shaft hole 30 is changed by the rotation in the circumferential direction. Therefore, in the golf club 2, the following relative relationship A and relative relationship B are considered.
[Relative relationship A] relative positional relationship in the circumferential direction between the hosel hole 18 of the head 4 and the shaft 6 [relative relationship B] circumferential direction between the hosel hole 18 of the head 4 and the sleeve 8 Relative positional relationship in

  In the present application, the relative relationship A is also referred to as a shaft position. In the present application, the relative relationship B is also referred to as a sleeve position. The combination of shaft position and sleeve position is infinite. These combinations enable various club adjustments.

  Here, from the viewpoint of facilitating the following description, a circumferential reference position Ch1 is defined for the head 4 (see FIG. 16). When the head 4 is grounded to the horizontal plane sh1 according to the real loft angle and the lie angle, a plane PL1 including the axis of the hosel hole and perpendicular to the horizontal plane sh1 is considered. There are two intersection lines between the plane PL1 and the inner surface of the hosel hole 18, and the position of the intersection line on the toe side is the circumferential reference position Ch1 (see FIG. 16). When the hosel hole 18 is viewed from above (grip side), the position 90 ° clockwise from the circumferential reference position Ch1 is the circumferential position Ch2 (see FIG. 16). When the hosel hole 18 is viewed from above (grip side), the position 180 ° clockwise from the head circumferential reference position Ch1 is the circumferential position Ch3. When the hosel hole 18 is viewed from above (grip side), the position 270 ° clockwise from the circumferential reference position Ch1 is the circumferential position Ch4.

  In the present application, “bending in the toe-down direction” means that the distal end side of the shaft is bent downward with the circumferential reference position Ch1 directly above.

  Furthermore, from the viewpoint of facilitating the following description, a circumferential reference position Cv1 is defined for the sleeve 8 (see FIG. 16). At the sleeve position where the real loft angle of the head 4 is maximized, the position corresponding to the circumferential reference position Ch1 is the circumferential reference position Cv1. That is, when the sleeve 8 is mounted in the hosel hole 18 so that the circumferential reference position Cv1 coincides with the circumferential reference position Ch1, the real loft angle is maximized. When the real loft angle is maximum, the hook angle is also maximum. As shown in the cross-sectional view of FIG. 16, when the sleeve 8 is viewed from the grip side (the side where the shaft hole 30 is open), the position 90 ° clockwise from the circumferential reference position Cv1 is the circumferential position Cv2. It is. When the sleeve 8 is viewed from the grip side, a position 180 ° clockwise from the circumferential reference position Cv1 is the circumferential position Cv3. When the sleeve 8 is viewed from the grip side, a position of 270 ° clockwise from the circumferential reference position Cv1 is the circumferential position Cv4.

[Sleeve position]
Due to the inclination angle θ1 of the sleeve, the hook angle and the like vary depending on the sleeve position. In the above embodiment, 12 sleeve positions are possible. The following seven positions are exemplified as this sleeve position.
(NU): Sleeve position with maximum lie angle. In other words, the sleeve position in which the circumferential position Cv4 coincides with the head circumferential direction reference position Ch1.
(Fa): A sleeve position obtained by rotating the sleeve at the above position (NU) counterclockwise by 30 ° as viewed from the grip side.
(Fb): A sleeve position obtained by rotating the sleeve at the position (NU) by 60 ° counterclockwise as viewed from the grip side.
(Fc): Sleeve position with maximum hook angle. In other words, the sleeve position obtained by rotating the sleeve at the above-mentioned position (NU) 90 ° counterclockwise as viewed from the grip side. In other words, the sleeve position where the circumferential position Cv1 coincides with the head circumferential direction reference position Ch1 (see FIG. 16).
(Sa): A sleeve position obtained by rotating the sleeve of the above position (NU) clockwise by 30 ° as viewed from the grip side.
(Sb): A sleeve position obtained by rotating the sleeve at the position (NU) by 60 ° clockwise as viewed from the grip side.
(Sc): Sleeve position at which the hook angle is minimized. In other words, the sleeve position obtained by rotating the sleeve at the above position (NU) 90 ° clockwise as viewed from the grip side. In other words, the sleeve position in which the circumferential position Cv3 coincides with the head circumferential direction reference position Ch1.

[Bending twist amount]
An anisotropic shaft twists in conjunction with bending (bending). This property is quantitatively evaluated by the “bending twist amount”. 17 and 18 are diagrams for explaining a method of measuring the bending twist amount. FIG. 17 is a side view showing a state of measurement, and FIG. 18 is a front view of the shaft 6 viewed from the tip Tp side. The upper side of FIG. 18 shows a state before the weight 52 is suspended, and the lower side of FIG. 18 shows a state after the weight 52 is suspended.

  In the measurement of the amount of bending twist, a jig 100 for fixing the rear end portion of the shaft, a straight bar 50, and a weight 52 are prepared.

  In the measurement of the bending twist amount, first, the rear end portion of the shaft 6 is fixed. The fixed range is a range from the rear end Bt of the shaft to 150 mm (see FIG. 17). Next, the rod 50 is fixed at a specific position in the circumferential direction of the shaft 6. The rod 50 is fixed to the uppermost side in the circumferential direction of the shaft 6 (see FIG. 18). This fixing is performed by, for example, an adhesive. In a state before the weight 52 is suspended, the bar 50 is horizontal (see FIG. 18). The rod 50 is fixed at a point 25 mm away from the shaft tip Tp (see FIG. 17). In FIG. 18, the bar 50 is a single straight line.

  Next, the weight 52 is suspended. The weight of the weight 52 is adjusted so that the amount of deflection is 60 mm. This amount of deflection is the movement distance of the rod 50 in the vertical direction (see FIGS. 17 and 18). The position (load point) of the weight 52 is a point separated by 50 mm from the shaft tip Tp (see FIG. 17). The shaft 6 is bent by the load of the weight 52. The shaft 6 is stopped in a bent state, and the inclination angle θt of the rod 50 is read (see FIG. 18). The maximum value of the inclination angle θt is the amount of bending twist. From the viewpoint of reading accuracy, the rod 50 should be relatively long, for example, 140 mm (see FIG. 18).

  The amount of bending twist can also be measured using a commercially available clinometer.

  In determining the amount of bending twist, the direction of twist is considered. In the measurement of FIG. 17, when the shaft 6 is viewed from the grip side (shaft rear end Bt side), the shaft 6 is twisted clockwise or counterclockwise due to bending by the weight 52. When viewed from the grip side, when the shaft 6 is twisted counterclockwise due to bending by the weight 52, the twist angle θt is positive. On the contrary, when viewed from the grip side, the twist angle θt is negative when the shaft 6 is twisted clockwise due to the bending by the weight 52. FIG. 18 shows a case where the twist angle θt is negative because the shaft 6 is viewed from the head side. The maximum value of the twist angle θt is the bending twist amount.

  As described above, the circumferential position of the shaft 6 as shown in FIG. 16 is defined. The shaft circumferential reference position Cs1 is a circumferential position where the twist angle θt becomes maximum when the weight is hung with the circumferential position directly above. On the other hand, when the measurement is performed with the circumferential position Cs3 directly above, the twist angle θt is minimum (a negative value). The twist angle θt is zero when measured with the circumferential position Cs2 that is 90 degrees apart from the circumferential reference position Cs1 in the circumferential direction directly above. The twist angle θt is also zero when measured with the circumferential position Cs4 separated by 270 ° in the circumferential direction from the shaft circumferential reference position Cs1 as just above.

  The twist angle θt varies depending on the bending direction. FIG. 19 is a graph showing the relationship between the bending direction and the twist angle θt. In this graph, the shaft circumferential direction reference position Cs1 corresponds to “90 °” on the horizontal axis of the graph. As shown in this graph, when the shaft circumferential reference position Cs1 is directly above and bent downward, the twist angle θt is the maximum. This maximum value is the amount of bending twist.

  From the viewpoint of improving the hit ball directivity while suppressing the tilt angle θ1, the bending twist is preferably 0.5 ° or more, more preferably 0.7 ° or more, and more preferably 0.9 ° or more. From the viewpoint of increasing the shaft strength and suppressing the production cost, the amount of bending twist is preferably 3.0 ° or less, more preferably 2.8 ° or less, and further preferably 2.6 ° or less.

[Shaft position]
The twist of the shaft at the impact changes depending on the shaft position. The following 12 positions are exemplified as this shaft position.
(N1): A shaft position obtained by rotating the shaft circumferential reference position Cs1 90 ° clockwise with respect to the head circumferential reference position Ch1 when viewed from the grip side. In other words, the shaft position in which the shaft circumferential direction reference position Cs1 is matched with the head circumferential direction position Ch2.
(F1): A shaft position obtained by rotating the shaft circumferential reference position Cs1 by 60 ° clockwise with respect to the head circumferential reference position Ch1 when viewed from the grip side.
(F2): A shaft position obtained by rotating the shaft circumferential reference position Cs1 clockwise by 30 ° with respect to the head circumferential reference position Ch1 when viewed from the grip side.
(F3): A shaft position in which the shaft circumferential reference position Cs1 is made to coincide with the head circumferential position Ch1 (see FIG. 16).
(F4): A shaft position obtained by rotating the shaft circumferential reference position Cs1 30 degrees counterclockwise with respect to the head circumferential reference position Ch1 when viewed from the grip side.
(F5): A shaft position obtained by rotating the shaft circumferential reference position Cs1 by 60 ° counterclockwise with respect to the head circumferential reference position Ch1 when viewed from the grip side.
(S1): A shaft position obtained by rotating the shaft circumferential reference position Cs1 clockwise by 120 ° with respect to the head circumferential reference position Ch1 when viewed from the grip side.
(S2): A shaft position obtained by rotating the shaft circumferential reference position Cs1 clockwise by 150 ° with respect to the head circumferential reference position Ch1 when viewed from the grip side.
(S3): A shaft position obtained by rotating the shaft circumferential reference position Cs1 180 degrees clockwise relative to the head circumferential reference position Ch1 when viewed from the grip side. In other words, the shaft position in which the shaft circumferential reference position Cs1 is made to coincide with the head circumferential position Ch3.
(S4): A shaft position obtained by rotating the shaft circumferential reference position Cs1 counterclockwise by 150 ° with respect to the head circumferential reference position Ch1 when viewed from the grip side.
(S5): A shaft position obtained by rotating the shaft circumferential reference position Cs1 counterclockwise by 120 ° with respect to the head circumferential reference position Ch1 when viewed from the grip side.
(N2): A shaft position obtained by rotating the shaft circumferential reference position Cs1 by 90 ° counterclockwise with respect to the head circumferential reference position Ch1 when viewed from the grip side. In other words, the shaft position in which the shaft circumferential direction reference position Cs1 is matched with the head circumferential direction position Ch4.

  The shaft position (N1) and the shaft position (N2) are positions where the shaft is not twisted due to bending in the toe-down direction.

  The combination of the shaft position and the sleeve position is not limited. Various combinations (fitting) are possible by this combination. The shaft position and the sleeve position can be adjusted to be suitable for each golfer, for example. Highly accurate custom fitting is possible by combining the shaft position and sleeve position.

  An example of the adjustment is to determine the shaft position and the sleeve position so that the trajectory is less bent. In this adjustment, for example, one golfer performs a test shot using a plurality of shaft-sleeve assemblies in which the relative positions in the circumferential direction of the shaft and the sleeve are different. In this trial hit, the golfer can try multiple sleeve positions in each of the multiple shaft-sleeve assemblies. The golfer has a shaft position and a sleeve position at which the best hitting result is obtained, and is suitable for the golfer.

  In the present application, the term “club position” is used in addition to the shaft position and the sleeve position. The club position is determined by a combination of the shaft position and the sleeve position.

  In the above embodiment, the sleeve 8 is bonded to the shaft 6. Preferably, the circumferential relative position of the sleeve 8 and the shaft 6 in this shaft-sleeve assembly is determined so that the preferred shaft position and the preferred sleeve position described above can be achieved.

  In the shaft-sleeve assembly, the circumferential relative position between the shaft and the sleeve is fixed. This fixing restricts the free combination of shaft position and sleeve position.

  When the golf club is commercially available, the shaft and the sleeve form a shaft-sleeve assembly. Typically, one shaft-sleeve assembly and one head are set and marketed. It is difficult and troublesome to separate and re-bond the shaft and sleeve once bonded. Therefore, it is difficult to change the circumferential relative position between the shaft and the sleeve. In the shaft-sleeve assembly, it is important that the circumferential relative position between the shaft and the sleeve is set within a preferable range.

From the viewpoint of suppressing slicing, in a preferable golf club, the sleeve and the shaft are fixed (adhered) so as to enable the following club position a1.
[Club position a1]: At the sleeve position (Fc) at which the hook angle is maximized, the shaft position is positioned so that the head is twisted in the closing direction due to bending in the toe-down direction.

From the viewpoint of further improving the correction of the slice, more preferably, the sleeve and the shaft are fixed (adhered) so as to enable the following club position a2.
[Club position a2]: When the sleeve position is the position (Fc), the shaft position is within the range from the position (F5) to the position (F1) (with an angular width of 120 degrees).

From the viewpoint of further improving the correction of the slice, more preferably, the sleeve and the shaft are fixed (adhered) so as to enable the following club position a3.
[Club position a3]: When the sleeve position is the position (Fc), the shaft position is within the range from the position (F4) to the position (F2) (within an angular width of 60 degrees).

From the viewpoint of further improving the correction of the slice, it is particularly preferable that the sleeve and the shaft are fixed (adhered) so as to enable the following club position a4.
[Club position a4]: When the sleeve position is the position (Fc), the shaft position is within the range of the position (F3) ± 10 °. In other words, at the sleeve position (Fc) at which the hook angle is maximum, the shaft position is within the range of an angular width of 20 degrees centered on the position (F3).

From the viewpoint of suppressing the hook, in the preferred golf club, the sleeve and the shaft are fixed (adhered) so as to enable the following club position b1.
[Club position b1]: At the sleeve position (Sc) at which the hook angle is minimum, the shaft position is positioned so as to be twisted in the direction in which the head opens due to bending in the toe-down direction.

From the viewpoint of further improving the correction of the hook, more preferably, the sleeve and the shaft are fixed (adhered) so as to enable the following club position b2.
[Club position b2]: At the sleeve position (Sc) at which the hook angle is minimum, the shaft position is within the range from the position (S5) to the position (S1) (the angular width is within a range of 120 degrees).

From the viewpoint of further improving the correction of the hook, more preferably, the sleeve and the shaft are fixed (adhered) so as to enable the following club position b3.
[Club position b3]: At the sleeve position (Sc) at which the hook angle is minimum, the shaft position is within the range from the position (S4) to the position (S2) (within an angular width of 60 degrees).

From the viewpoint of further improving the hook correction, it is particularly preferable that the sleeve and the shaft are fixed (adhered) so as to enable the following club position b4.
[Club position b4]: At the sleeve position (Sc) at which the hook angle is minimum, the shaft position is within the range of the position (S3) ± 10 °. In other words, at the sleeve position (Sc) at which the hook angle is minimum, the shaft position is within the range of an angular width of 20 degrees with the position (S3) as the center.

  As described above, the fixing of the shaft and the sleeve restricts the free combination of the shaft position and the sleeve position. However, even under this constraint, a single shaft-sleeve assembly can provide both a club position for a slicer and a club position for a hooker. From this viewpoint, the following embodiment is preferable.

  From the viewpoint of increasing the degree of freedom of club adjustment, it is preferable that the sleeve is fixed (adhered) to the shaft so that the club position a1 and the club position b1 are possible.

  From the viewpoint of further increasing the degree of freedom in adjusting the club, it is preferable that the sleeve is fixed (adhered) to the shaft so that the club position a2 and the club position b2 are possible.

  From the viewpoint of further increasing the degree of freedom in adjusting the club, it is preferable that the sleeve is fixed (adhered) to the shaft so that the club position a3 and the club position b3 are possible.

  From the viewpoint of particularly increasing the degree of freedom in adjusting the club, it is preferable that the sleeve is fixed (adhered) to the shaft so that the club position a4 and the club position b4 are possible.

  The shaft position can be determined taking into account the bending of the shaft on impact. The shaft position is determined such that bending of the shaft at impact causes the shaft to twist as intended.

  A typical example of shaft bending at impact is shaft bending due to toe down. By considering toe down, many golfers can obtain a hook or slice correction effect.

  FIG. 16 shows a case where the shaft circumferential direction reference position Cs1 is matched with the head circumferential direction reference position Ch1. That is, in FIG. 16, the shaft position (F3) is shown. In this case, twisting that closes the face surface in conjunction with the deflection of the shaft 6 accompanying the toe-down phenomenon occurs most effectively.

  FIG. 16 shows a case where the sleeve circumferential reference position Cv1 is made to coincide with the head circumferential reference position Ch1. This sleeve position maximizes the hook angle. That is, in FIG. 16, the sleeve position (Fc) is shown.

  As described above, in FIG. 16, the position (F3) is adopted as the shaft position, and the position (Fc) is adopted as the sleeve position. The configuration of FIG. 16 is suitable for a golfer who can easily slice a hit ball.

  Even the same golfer may have different trajectories (ballistic trajectories) depending on the day of play. For example, in a certain golf player X, there are cases where the degree of slicing is large and when the degree of slicing is small. In such a case, by changing the shaft position and the sleeve position, the degree of the slice correction effect due to anisotropy can be adjusted, and the hook angle can be adjusted.

  As the bending (deflection) of the shaft at the time of impact, bending due to a so-called toe-down phenomenon can be considered, but other bendings can also be considered. This bend at the time of impact can vary from golfer to golfer. Golfers can make trials at several club positions. Based on the results of this trial, you can find a club position that suits you.

  The material of the head body 14 is not limited. Examples of preferable materials include metals, CFRP (carbon fiber reinforced plastics), and combinations thereof, and metals are more preferable. Examples of the metal include titanium alloy, stainless steel, aluminum alloy, magnesium alloy, and combinations thereof. The manufacturing method of each member which comprises the head main body 14 is not limited, Forging, casting, a press, and these combination are illustrated. The head body 14 may be formed by joining a plurality of members.

  The material of the shaft 6 is preferably CFRP (carbon fiber reinforced plastic).

  The material of the sleeve 8 is not limited. Preferred materials include titanium alloy, stainless steel, aluminum alloy, magnesium alloy and resin. From the viewpoint of strength and lightness, for example, an aluminum alloy and a titanium alloy are more preferable. As the resin, a resin excellent in mechanical strength is preferable, and for example, a resin called engineering plastic or super engineering plastic is preferable.

  The material of the engaging member 16 is not limited. Preferred materials include titanium alloy, stainless steel, aluminum alloy, magnesium alloy and resin. As the resin, a resin excellent in mechanical strength is preferable, and for example, a resin called engineering plastic or super engineering plastic is preferable. As described above, the engaging member 16 may be integrally formed with the head body. More preferably, from the viewpoint of securing the engagement member 16, the engagement member 16 may be formed of a material that can be welded to the head body 14.

  The material of the screw 10 is not limited. Preferred materials include titanium alloy, stainless steel, aluminum alloy, magnesium alloy and the like.

The prepreg that can be used as the material for the shaft is not limited. Table 1 below shows examples of usable prepregs. From the viewpoint of the amount of bending twist and the strength of the shaft, a prepreg having a tensile modulus of fiber of 40 (t / mm ² ) is particularly preferable for the anisotropically expressing sheet.

  From the viewpoint of increasing the amount of bending twist and increasing the twist strength, the absolute value of the fiber orientation angle Ag of the anisotropically-expressing sheet is preferably 10 ° or more, and more preferably 15 ° or more. From the viewpoint of increasing the amount of bending twist and the viewpoint of increasing the bending strength, the absolute value of the fiber orientation angle Ag of the anisotropically developed sheet is preferably 40 ° or less, more preferably 35 ° or less, More preferably, it is 30 ° or less.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Production of shaft]
The shaft E1, the shaft E2, the shaft E3, the shaft E4, and the shaft E5 were produced as follows.

[Shaft E1 (for Example 1)]
A shaft having the laminated structure shown in FIG. 12 was produced, and a shaft having a bending twist of 1.0 ° was obtained. The amount of bending twist was adjusted based on the thickness of the anisotropic expression sheet, the fiber weight of the anisotropic expression sheet, the thickness of the bias layer sheet, and the fiber weight of the bias layer sheet. The sheet t3 and the sheet t4 are bias layer sheets and anisotropic expression sheets.

  A prepreg manufactured by Mitsubishi Rayon Co., Ltd. having a carbon fiber product number “TR50S” was used as the straight layer sheet. The straight layer sheet is a sheet labeled “0 °”.

  A prepreg manufactured by Mitsubishi Rayon Co., Ltd., whose carbon fiber product number is “MR40” was used for the anisotropic expression sheet. As the hoop layer sheet, a trade name “805S-3” manufactured by Toray Industries, Inc. was used. The total length of the shaft was 1143 mm.

  FIG. 12 shows the number of plies (ply number) of each sheet in the shaft E1. On the left side of the seat, the number of plies in the bat Bt is shown. On the right side of the sheet, the number of plies in the chip Tp is shown.

[Shaft E2 (for Example 2)]
A shaft having the laminated structure shown in FIG. 15 was produced, and a shaft having a bending twist of 2.0 ° was obtained. The amount of bending twist was adjusted based on the thickness of the anisotropic expression sheet and the fiber basis weight of the anisotropic expression sheet. The anisotropic expression sheets are the sheet r3, the sheet r4, the sheet r5, and the sheet r6.

  A prepreg manufactured by Mitsubishi Rayon Co., Ltd. having a carbon fiber product number “TR50S” was used as the straight layer sheet. The straight layer sheet is a sheet labeled “0 °”.

  A prepreg manufactured by Mitsubishi Rayon Co., Ltd., whose carbon fiber product number is “MR40” was used for the anisotropic expression sheet. As the hoop layer sheet, a trade name “805S-3” manufactured by Toray Industries, Inc. was used. The total length of the shaft was 1143 mm.

  FIG. 15 shows the number of plies (ply number) of each sheet on the shaft E2. On the left side of the seat, the number of plies in the bat Bt is shown. On the right side of the sheet, the number of plies in the chip Tp is shown.

[Shaft E3 (for Example 3)]
A shaft having the laminated structure shown in FIG. 12 was produced, and a shaft having a bending twist of 2.0 ° was obtained. The amount of bending twist is adjusted by adjusting the fiber elastic modulus (tensile modulus) of the anisotropically expressing sheet, the thickness of the anisotropically expressing sheet, and the fiber basis weight of the anisotropically expressing sheet. A shaft E3 was obtained in the same manner as the shaft E1 except that the angle was set to 0 °.

[Shaft E4 (for Comparative Example 1)]
In the anisotropic expression sheet used in the shaft E1, the arrangement in the circumferential direction was changed. By this arrangement change, a shaft E4 having no anisotropy was obtained. In this shaft E4, 0.5 ply bias layers inclined in the same direction were arranged at a circumferential position from 0 ° to 180 ° and a circumferential position from 180 ° to 360 °. With this arrangement, the anisotropy was canceled between the 0.5 ply bias layers, and a shaft E4 having no anisotropy was obtained.

[Shaft E5 (for Comparative Example 2)]
A shaft having the laminated configuration shown in FIG. 10 was produced, and a shaft E5 having a bending twist of 4.0 ° was obtained. The amount of bending twist was adjusted based on the thickness of the anisotropic expression sheet, the fiber weight of the anisotropic expression sheet, the thickness of the bias layer sheet, and the fiber weight of the bias layer sheet.

  A prepreg manufactured by Mitsubishi Rayon Co., Ltd. having a carbon fiber product number “TR50S” was used as the straight layer sheet. The straight layer sheet is a sheet labeled “0 °”.

  A prepreg manufactured by Mitsubishi Rayon Co., Ltd., whose carbon fiber product number is “MR40” was used for the anisotropic expression sheet. As the hoop layer sheet, a trade name “805S-3” manufactured by Toray Industries, Inc. was used. The total length of the shaft was 1143 mm.

  FIG. 10 shows the number of plies (ply number) of each sheet in the shaft E5. On the left side of the seat, the number of plies in the bat Bt is shown. On the right side of the sheet, the number of plies in the chip Tp is shown.

  In addition, although the shaft E5 is used for the golf club of the comparative example, this shaft E5 can also be used for the golf club according to the present invention.

[Shaft strength]
The strength of each shaft was measured. As the three-point bending strength test, an SG type three-point bending strength test was adopted. This is a test established by the Product Safety Association. In this test, while the shaft is supported from below at two support points, a load F is applied from the top to the bottom at the load point. The position of the load point is a position that bisects the two support points. The load point is the measurement point. The measurement points are T point, A point, B point, and C point. The T point is a point 90 mm from the chip Tp. A point is a point of 175 mm from the chip Tp. B point is a point of 525 mm from the chip Tp. C point is a point of 175 mm from bat Bt. The value (peak value) of the load F when the shaft was broken was measured. When the T point is measured, the distance S between the two support points is 150 mm. When the points A, B, and C are measured, the interval S is set to 300 mm. The results are shown in Table 2 below.

  The SG type torsion test was adopted as a method for measuring the twist fracture strength. This is also a test established by the Product Safety Association. In this test, first, fixing jigs are bonded to both ends of the shaft. Then, torque is applied to the shaft by rotating the jig on the tip side while the jig on the bat side is fixed. The value obtained by multiplying the torque value when the shaft is broken by the twist angle is the twist fracture strength. The results are shown in Table 2 below.

[Shaft-Sleeve Assembly A1 According to Example 1]
A sleeve having the inclination angle θ1 of 0.8 ° was prepared. This sleeve was bonded to the tip end portion of the shaft E1 to obtain a shaft-sleeve assembly A1. The relative position in the circumferential direction between the shaft and the sleeve was determined so that the shaft position and the sleeve position shown in the table to be described later were realized. The length of the shaft-sleeve assembly was set so that the club length was 45.5 inches.

[Shaft-sleeve assembly A2 according to Example 2]
A sleeve having the inclination angle θ1 of 0.4 ° was prepared. This sleeve was bonded to the tip end portion of the shaft E2 to obtain a shaft-sleeve assembly A2. The relative position in the circumferential direction between the shaft and the sleeve was determined so that the shaft position and the sleeve position shown in the table to be described later were realized. The length of the shaft-sleeve assembly was set so that the club length was 45.5 inches.

[Shaft-sleeve assembly A3 according to Example 3]
A sleeve having the inclination angle θ1 of 0.8 ° was prepared. This sleeve was bonded to the tip of the shaft E3 to obtain a shaft-sleeve assembly A3. The relative position in the circumferential direction between the shaft and the sleeve was determined so that the shaft position and the sleeve position shown in the table to be described later were realized. The length of the shaft-sleeve assembly was set so that the club length was 45.5 inches.

[Shaft-sleeve assembly A4 according to comparative example 1]
A sleeve having the inclination angle θ1 of 1.5 ° was prepared. This sleeve was bonded to the tip of the shaft E4 to obtain a shaft-sleeve assembly A4. The relative position in the circumferential direction between the shaft and the sleeve was determined so that the shaft position and the sleeve position shown in the table to be described later were realized. The length of the shaft-sleeve assembly was set so that the club length was 45.5 inches.

[Shaft-sleeve assembly A5 according to comparative example 2]
A sleeve having the inclination angle θ1 of 0 ° was prepared. That is, a sleeve having no inclination angle θ1 was prepared. This sleeve was bonded to the tip of the shaft E5 to obtain a shaft-sleeve assembly A5. The relative position in the circumferential direction between the shaft and the sleeve was determined so that the shaft position and the sleeve position shown in the table to be described later were realized. The length of the shaft-sleeve assembly was set so that the club length was 45.5 inches.

[Preparation of head]
The engaging member and the head main body were welded to obtain the head shown in FIGS. This head was a so-called driver (W # 1) head. The volume of this head was 460 cc. The engaging member was disposed at a predetermined position, and this engaging member was welded to the head body. Laser welding was used as the welding method. The same head was used in all examples and comparative examples.

[Golf Clubs of Examples and Comparative Examples]
Each of the above-described shaft-sleeve assemblies A1 to A5 and the above-described head were coupled using screws to obtain a golf club. In all the examples and comparative examples, one head was used in common.

[tester]
Four testers (testers A to D) actually hit golf balls and evaluated them. The average value of 5 balls is shown in the table below. These four testers are all right-handed golfers. The characteristics of each tester are as follows.
[Tester A]: A golfer whose ball is a slice.
[Tester B]: A golfer whose ball is a slice.
[Tester C]: A golfer whose ball is a hook.
[Tester D]: A golfer whose ball is a hook.

  The tester A and the tester B are so-called slicers and easily slice the hit ball. The tester C and the tester D are so-called hookers and easily hook the hit ball.

  The club position according to the characteristics of each tester was adopted, and the straightening effect of the slice or hook was evaluated. This correction effect was confirmed by the arrival point of the ball. The left side of the ball arrival point is that the slice is corrected. The more right the “left / right shift” of the ball arrival point is, the more the hook is corrected. At the same time, “easy to hold” and “laterality” were evaluated as sensory evaluations. This evaluation is a five-step evaluation from 1 to 5, and the higher the score, the higher the evaluation.

[Evaluation by tester A]
Tester A, which is easy to slice, evaluated the straightening effect of the slice. The club positions were four types, “neutral”, “hook 1”, “hook 2” and “hook 3”. The sleeve position and shaft position at each club position are as shown in the table. The evaluation results are shown in Tables 3 and 4 below.

[Evaluation by tester B]
Tester B, which is easy to slice, evaluated the straightening effect of the slice. The club positions were four types, “neutral”, “hook 1”, “hook 2” and “hook 3”. The sleeve position and shaft position at each club position are as shown in the table. The evaluation results are shown in Tables 5 and 6 below.

[Evaluation by tester C]
Tester C, which is easy to hook, evaluated the correction effect of the hook. The club positions were “Neutral”, “Slice 1”, “Slice 2” and “Slice 3”. The sleeve position and shaft position at each club position are as shown in the table. The evaluation results are shown in Table 7 and Table 8 below.

[Evaluation by tester D]
Tester D, which is easy to hook, evaluated the correction effect of the hook. The club positions were “Neutral”, “Slice 1”, “Slice 2” and “Slice 3”. The sleeve position and shaft position at each club position are as shown in the table. The evaluation results are shown in Table 9 and Table 10 below.

  In the example, it was possible to obtain a club excellent in the effect of correcting hooks or slices, ease of holding, and laterality. It is also possible to select a club position depending on whether the priority is given to the correction effect of hooks or slices, ease of holding, or left-right direction.

  In these embodiments, the circumferential relative positions of the shaft and the sleeve in the shaft-sleeve assembly are set appropriately. A preferable range of this setting is as described above.

  The “counterclockwise angle” shown in Table 3 to Table 10 indicates how many times the shaft-sleeve assembly is rotated counterclockwise as viewed from the grip side.

  In all the club positions of the embodiment, the circumferential relative positions of the shaft and the sleeve are common. Thus, the seven club positions shown in the above table are realized by one shaft-sleeve assembly. For example, referring to Example 1, “Neutral”, “Hook 1”, “Hook 2”, “Hook 3”, “Slice 1”, “Slice 2” and “Slice 3” are the shaft-sleeve assemblies described above. This is achieved only by rotating A1. The golf club of the example is effective for both a hooker and a slicer, and has excellent adjustability. In the embodiment, seven club positions are realized simply by rotating the shaft-sleeve assembly. Therefore, adjustment is extremely easy.

  As shown in the above table, the example is superior to the comparative example. The advantages of the present invention are clear.

  The invention described above can be applied to any golf club.

DESCRIPTION OF SYMBOLS 2 ... Golf club 4 ... Head 6 ... Shaft 8 ... Sleeve 10 ... Screw 12 ... Feral 14 ... Head main body 16 ... Engagement member 18 ... Hosel hole DESCRIPTION OF SYMBOLS 19 ... Through-hole 20 ... Sole hole 22 ... Screw head 24 ... Screw axial part 30 ... Shaft hole 32 ... Screw hole s1 to s21 ... Cut prepreg Sheets t1 to t14 ... Cut prepreg sheet r1 to r11 ... Cut prepreg sheet Cs1 ... Shaft circumferential reference position Ch1 ... Head circumferential reference position

Claims (5)

It has a head having a hosel hole, a shaft, and an attaching / detaching mechanism,
The attachment / detachment mechanism has a sleeve positioned between the hosel hole and the shaft;
The head and the sleeve can be attached and detached,
The attachment / detachment mechanism makes it possible to fix the shaft to the hosel hole of the head at a plurality of sleeve positions,
The axis of the shaft is inclined at an inclination angle θ1 with respect to the axis of the hosel hole,
The shaft has anisotropy that causes twisting in conjunction with bending,
The head and the shaft can be attached and detached without breaking the adhesive.
The relative positional relationship in the circumferential direction between the hosel hole of the head and the sleeve is the sleeve position,
When the relative positional relationship in the circumferential direction between the hosel hole of the head and the shaft is a shaft position,
The club position is determined by the combination of the shaft position and the sleeve position.
The sleeve is fixed to the shaft to form a shaft-sleeve assembly,
Due to the multiple sleeve positions, a single shaft-sleeve assembly can provide both the club position for the slicer and the club position for the hooker ,
In the shaft-sleeve assembly, a golf club in which a circumferential relative position between the shaft and the sleeve is set so that the next club position a1 is possible .
[Club position a1]: In the sleeve position where the hook angle is maximum, the shaft position is positioned so that the head is twisted in the closing direction due to bending in the toe-down direction.  It has a head having a hosel hole, a shaft, and an attaching / detaching mechanism,
  The attachment / detachment mechanism has a sleeve positioned between the hosel hole and the shaft;
  The head and the sleeve can be attached and detached,
  The attachment / detachment mechanism makes it possible to fix the shaft to the hosel hole of the head at a plurality of sleeve positions,
  The axis of the shaft is inclined at an inclination angle θ1 with respect to the axis of the hosel hole,
  The shaft has anisotropy that causes twisting in conjunction with bending,
  The head and the shaft can be attached and detached without breaking the adhesive.
  The relative positional relationship in the circumferential direction between the hosel hole of the head and the sleeve is the sleeve position,
  When the relative positional relationship in the circumferential direction between the hosel hole of the head and the shaft is a shaft position,
  The club position is determined by the combination of the shaft position and the sleeve position.
  The sleeve is fixed to the shaft to form a shaft-sleeve assembly,
  Due to the multiple sleeve positions, a single shaft-sleeve assembly can provide both the club position for the slicer and the club position for the hooker,
  In the shaft-sleeve assembly, a golf club in which a circumferential relative position between the shaft and the sleeve is set so that the next club position b1 is possible.
  [Club position b1]: In the sleeve position where the hook angle is minimum, the shaft position is positioned so that the head is twisted in the opening direction due to bending in the toe-down direction. The golf club according to claim 1 or 2 , wherein the inclination angle θ1 is not less than 0.2 ° and not more than 1.0 °. The attachment / detachment mechanism includes the sleeve, a rotation preventing portion that restricts relative rotation between the sleeve and the hosel hole, and a slip prevention portion that restricts relative axial movement of the sleeve and the hosel hole. And
4. The golf club according to claim 1, wherein the rotation preventing portion and the slipping preventing portion can be fixed at a plurality of the sleeve positions. 5. The golf club according to any one of claims 1 to 4 , wherein a bending twist amount of the shaft is not less than 0.5 ° and not more than 3.0 °.

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