Patent Publication Number: US-10328318-B2

Title: Golf club

Description:
The present application claims priority on Patent Application No. 2017-110201 filed in JAPAN on Jun. 2, 2017, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a golf club. 
     Description of the Related Art 
     A golf club including a head and a shaft detachably attached to the head has been proposed. 
     Each of US2013/0017901 and U.S. Pat. No. 7,980,959 discloses a golf club including a head and a shaft detachably attached to the head. In these golf clubs, a sleeve is attached to a tip end portion of the shaft, and a shaft hole provided in the sleeve is inclined. In these golf clubs, an inclination direction of a shaft axis is changed depending on a fixed position of the sleeve in a circumferential direction. This change enables a loft angle, a lie angle, and a face angle to be adjusted. 
     Japanese patent No. 5645936 (US2010/0197423) discloses a golf club having a shaft adapter and a head adapter. The degree of freedom of an inclination direction of a shaft axis can be improved by the shaft adapter and the head adapter. 
     Japanese Patent Application Publication No. 2006-42950 discloses a golf club including: a retaining part bonded to a tip end portion of a shaft; a pair of angle adjustment parts which externally surround the retaining part, and a fixing nut which is screw-connected to male screw parts formed on upper end portions of the angle adjustment parts. 
     SUMMARY OF THE INVENTION 
     In a conventional technique, a sleeve is fixed to a head by using a screw that is screw-connected to the sleeve. The screw requires high strength. In addition, the conventional technique places a significant burden on the screw. Furthermore, the degree of freedom of angle adjustment is limited. 
     A possible solution for these problems is to use a configuration using reverse-tapered fitting. However, the reverse-tapered fitting may cause backlash. Tightening the reverse-tapered fitting to solve the problem of backlash makes it difficult to release the fitting. 
     It is an object of the present disclosure to provide a golf club capable of enjoying the advantage of the reverse-tapered fitting while solving the problem thereof. 
     In one aspect, a golf club may include: a head having a hosel part; a shaft; a tip engagement part having a reverse-tapered shape and being disposed at a tip end portion of the shaft; and a screw member. The tip engagement part may include a sleeve having a reverse-tapered shape and being fixed to the tip end portion of the shaft. The hosel part may include a hosel hole. The hosel hole may include a reverse-tapered hole having a shape corresponding to a shape of an outer surface of the tip engagement part. The tip engagement part may be fitted to the reverse-tapered hole. The sleeve may have a sleeve-side connection part at a tip end portion thereof. The screw member may have a screw-side connection part that can be detachably connected to the sleeve-side connection part, and a male screw part. The head may have, on a lower side of the hosel hole, a female screw part that can be screw-connected to the male screw part. When the male screw part is rotated in a first direction with respect to the female screw part, the screw member may press the tip engagement part in an engaging direction. When the male screw part is rotated in a second direction with respect to the female screw part while maintaining connection between the sleeve-side connection part and the screw-side connection part, the screw member may pull the tip engagement part in an engagement releasing direction. 
     In another aspect, by the rotation in the first direction, the screw member may press the tip engagement part in the engaging direction, and the sleeve-side connection part may be inserted to the screw-side connection part. The connection may be automatically completed by the sleeve-side connection part being inserted to the screw-side connection part. 
     In another aspect, the screw member may include: a screw body having the male screw part; a first member constituting an outer circumferential surface of the screw-side connection part; a second member positioned inside the first member; a third member positioned inside the second member; a first elastic body that is disposed between the first member and the second member, and biases the first member to a sleeve side with respect to the second member; a second elastic body that biases the third member to the sleeve side; and an engagement ball disposed in a ball housing hole penetrating between an inner surface and an outer surface of the second member. The sleeve-side connection part may have an engagement recess. In a non-connected state, the engagement ball may be projected outside the second member by the third member being positioned inside the engagement ball, and, by the projected engagement ball, the first member may be located at a first position at which movement thereof to the sleeve side is regulated. In a connected state in which the connection has been achieved, the third member may be moved to a position at which the third member is removed from inside of the engagement ball by the sleeve-side connection part, the engagement ball may fall in the engagement recess of the sleeve-side connection part, and the movement regulation on the first member by the engagement ball may be released, whereby the first member may be moved to a second position at which the projection of the engagement ball to the outside is prevented. 
     In another aspect, the screw member may include: a screw body part having the male screw part; an elastic deformation part extending from the screw body part to a sleeve side and constituting the screw-side connection part; and a rotating engagement part to which a wrench for rotating the screw member can be inserted. The rotating engagement part may have a through hole penetrating the screw body part, and an inner surface of the elastic deformation part that extends continuously with the through hole. The elastic deformation part may have an engagement projection at an end portion thereof on a sleeve side, and the end portion on the sleeve side is a free end. The sleeve-side connection part may have a hollow portion opened on a side of the screw member, an inner surface defining the hollow portion, and an engagement recess provided on the inner surface. In a natural state, the elastic deformation part including the engagement projection may exhibit a shape that can be inserted to the hollow portion with rotation of the screw member in the first direction. When the wrench is inserted to a position at which the wrench abuts on the inner surface of the elastic deformation part, the elastic deformation part may be elastically deformed so as to be positioned at a position at which the engagement projection of the elastic deformation part can be engaged with the engagement recess. 
     In one aspect, a screw member may be used for a golf club including: a head having a hosel part; a shaft; and a tip engagement part having a reverse-tapered shape and being disposed at a tip end portion of the shaft. The tip engagement part may include a sleeve having a reverse-tapered shape and being fixed to the tip end portion of the shaft. The hosel part may include a hosel hole. The hosel hole may include a reverse-tapered hole having a shape corresponding to a shape of an outer surface of the tip engagement part. The tip engagement part may be fitted to the reverse-tapered hole. The sleeve may have a sleeve-side connection part at a tip end portion thereof. The screw member may have a screw-side connection part that can be detachably connected to the sleeve-side connection part, and a male screw part. The head may have, on a lower side of the hosel hole, a female screw part that can be screw-connected to the male screw part. When the male screw part is rotated in a first direction with respect to the female screw part, the screw-side connection part may be connected to the sleeve-side connection part with progression of the screw-connection. When the male screw part is rotated in a second direction with respect to the female screw part, while maintaining connection between the sleeve-side connection part and the screw-side connection part, the screw member may pull the tip engagement part in an engagement releasing direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a golf club according to a first embodiment; 
         FIG. 2  is a perspective view of the golf club in  FIG. 1  as viewed from a sole side; 
         FIG. 3  is an exploded perspective view of the golf club in  FIG. 1 ; 
         FIG. 4  is an assembling process view of the golf club in  FIG. 1 ; 
         FIG. 5  is a sectional view of the golf club in  FIG. 1 , and  FIG. 5  is the sectional view at a hosel part; 
         FIG. 6  is a bottom view in the vicinity of a tip engagement part according to a first embodiment; 
         FIG. 7  is a bottom view of the vicinity of a tip engagement part according to a modification example; 
         FIG. 8  is a perspective view of a spacer; 
         FIG. 9( a )  is a sectional view of the spacer in  FIG. 8 ,  FIG. 9( b )  is a partial sectional view of a spacer of a modification example, and  FIG. 9( c )  is a partial sectional view of a spacer of a modification example; 
         FIG. 10  is a perspective view of a spacer according to a modification example; 
         FIG. 11  is a sectional view of a golf club according to a modification example; 
         FIG. 12  is plan views showing the position of a lower end surface of the tip engagement part, and shows variations of a position of a center line of the shaft, and  FIG. 12  to  FIG. 15  show 16 kinds of constitutions which can be set when the number of spacers is one; 
         FIG. 13  is also plan views showing the position of the lower end surface of the tip engagement part, and shows variations of the position of the center line of the shaft; 
         FIG. 14  is also plan views showing the position of the lower end surface of the tip engagement part, and shows variations of the position of the center line of the shaft; 
         FIG. 15  is also plan views showing the position of the lower end surface of the tip engagement part, and shows variations of the position of the center line of the shaft; 
         FIG. 16  is plan views showing the position of the lower end surface of the tip engagement part, and shows variations of the position of the center line of the shaft; 
         FIG. 16  and  FIG. 17  show 8 kinds out of 64 kinds of constitutions which can be set when the number of spacers is two; 
         FIG. 17  is also plan views showing the position of the lower end surface of the tip engagement part, and shows variations of the position of the center line of the shaft; 
         FIG. 18  is plan views of nine sleeves; 
         FIG. 19  is sectional views (radial-direction sectional views) for illustrating a club length adjustment mechanism by changing a rotation position; 
         FIG. 20  is sectional views (axial-direction sectional views) for illustrating the club length adjustment mechanism by changing the rotation position; 
         FIG. 21  is a perspective view of a sleeve according to another embodiment; 
         FIG. 22( a )  is a top view of the sleeve shown in  FIG. 21 ,  FIG. 22( b )  is a sectional view taken along line B-B in  FIG. 21 ,  FIG. 22( c )  is a sectional view taken along line C-C in  FIG. 21 , and  FIG. 22( d )  is a bottom view of the sleeve; 
         FIG. 23( a )  to  FIG. 23( d )  show a hosel hole corresponding to the sleeve shown in  FIG. 21 ,  FIG. 23( a )  is a plan view of an upper end of the hosel hole,  FIG. 23( b )  and  FIG. 23( c )  are sectional views of the hosel hole, and  FIG. 23( d )  is a plan view of a lower end of the hosel hole; 
         FIG. 24( a )  is a plan view of a sleeve and a hosel hole in an engagement state (a second phase state), and  FIG. 24( b )  is a bottom view of the sleeve and the hosel hole in the engagement state (the second phase state); 
         FIG. 25  is a sectional view taken along line A-A in  FIG. 24( a ) , and  FIG. 25  is also a sectional view taken along line A-A in  FIG. 24( b ) ; 
         FIG. 26  is a plan view showing a relationship between a bottom surface of the sleeve the upper end of the hosel hole in a first-phase state, and  FIG. 26  shows a most difficult situation for inserting the sleeve into the hosel hole; 
         FIG. 27  is a front view of a golf club according to another embodiment; 
         FIG. 28  is an exploded perspective view of the golf club in  FIG. 27 ; 
         FIG. 29  is an assembling process view of the golf club in  FIG. 27 ; 
         FIG. 30  is a sectional view of a screw member according to a first embodiment, and  FIG. 30  is a sectional view in a non-connected state; 
         FIG. 31  is a sectional view when the screw member in  FIG. 30  is brought into a connected state; 
         FIG. 32  is a sectional view showing a screw member and a sleeve according to another embodiment; 
         FIG. 33  is a sectional view when the screw member and the sleeve in  FIG. 32  are brought into the connected state; 
         FIG. 34  is sectional views including a sleeve according to another embodiment, the sleeve according to  FIG. 34  has a movable connection part, the movable connection part constitutes a sleeve-side connection part, and  FIG. 34  is sectional views for illustrating movements of the movable connection part; and 
         FIG. 35  is sectional views for illustrating movements of the movable connection part, as with  FIG. 34 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, preferred embodiments will be described in detail with appropriate references to the accompanying drawings. 
     Unless otherwise described, “a circumferential direction” in the present application means a circumferential direction of a shaft. Unless otherwise described, “an axial direction” in the present application means a direction of a center line of the shaft or a hosel hole. Unless otherwise described, “an axial perpendicular direction” in the present application means a direction orthogonally crossing the axial direction of the shaft. Unless otherwise described, a section in the present application means a section along a plane perpendicular to the center line of the shaft. Unless otherwise described, a grip side is defined as an upper side, and a sole side is defined as a lower side. 
       FIG. 1  shows a golf club  100  which is a first embodiment.  FIG. 1  shows only the vicinity of a head of the golf club  100 .  FIG. 2  is a perspective view of the golf club  100  as viewed from a sole side.  FIG. 3  is an exploded perspective view of the golf club  100 . 
     The golf club  100  has a head  200 , a shaft  300 , a sleeve  400 , a spacer  500 , and a grip (not shown in the drawings). The sleeve  400  and the spacer  500  constitute the tip engagement part RT. The tip engagement part RT is disposed at a tip end portion of the shaft  300 . An outer surface of the tip engagement part RT is formed by the spacer  500 . 
     The type of the head  200  is not limited. The head  200  of the present embodiment is a wood type head. The head  200  may be a hybrid type head, an iron type head, a putter head or the like. The wood type head may be a driver head, or may be a head of a fairway wood. 
     The shaft  300  is not limited, and a commonly used shaft may be used. For example, a carbon shaft and a steel shaft may be used. 
     Although not shown in the drawings, the shaft  300  has a diameter varying with an axial direction position thereof. The diameter of the shaft  300  is increased toward the grip side. The sleeve  400  is fixed to the tip end portion of the shaft  300 . The tip end portion of the shaft  300  is the thinnest portion in the shaft  300 . 
     In the present embodiment, the number of the spacers  500  is one. The spacer  500  may not be present. The number of the spacers may be two. That is, two spacers may be stacked. In other words, the spacer may be double-layered. The number of the spacers may be three or more. For example, three spacers may be stacked. In other words, the spacer may be triple-layered. 
     The head  200  has a hosel part  202 . The hosel part  202  has a hosel hole  204 . The hosel hole  204  has a reverse-tapered hole  206 . The shape of the reverse-tapered hole  206  corresponds to the shape of the outer surface of the tip engagement part RT. The shape of the reverse-tapered hole  206  corresponds to the shape of the outer surface of the spacer  500 . In an engagement state, the outer surface of the tip engagement part RT (the outer surface of the spacer  500 ) is brought into surface-contact with the reverse-tapered hole  206 . The outer surface of the tip engagement part RT has a plurality of (four) planes, and all of the planes are brought into surface-contact with the reverse-tapered hole  206 . 
     The hosel part  202  (reverse-tapered hole  206 ) exists over the whole circumferential direction. The hosel part  202  (reverse-tapered hole  206 ) is continuous without a gap in the whole circumferential direction. The hosel part  202  is not split in the circumferential direction. The hosel part  202  does not have a slit (hosel slit) formed such that a part of the hosel part in the circumferential direction is lacking. The hosel part may have the slit. An embodiment having the slit will be described later. 
     As with a usual head, the head  200  has a crown  208 , a sole  210 , and a face  212  (see  FIGS. 1 to 3 ). 
     As shown in  FIG. 3 , the sleeve  400  has an inner surface  402  and an outer surface  404 . The inner surface  402  forms a shaft hole. The sectional shape of the inner surface  402  is a circle. The shape of the inner surface  402  corresponds to the shape of an outer surface of the shaft  300 . The inner surface  402  is fixed to the tip end portion of the shaft  300 . That is, the sleeve  400  is fixed to the tip end portion of the shaft  300 . An adhesive is used for the fixation. 
     The outer surface  404  is a pyramid surface. The outer surface  404  is a four-sided pyramid surface. The sectional shape of the outer surface  404  is a non-circle. The sectional shape of the outer surface  404  is a polygon (regular polygon). The sectional shape of the outer surface  404  is a tetragon. The sectional shape of the outer surface  404  is a square. The area of a figure formed by a sectional line of the outer surface  404  is increased toward a tip side of the shaft  300 . That is, the sleeve  400  has a reverse-tapered shape. 
     The sleeve  400  has a sleeve-side connection part  410 . The sleeve-side connection part  410  is provided at a tip end portion (lower end portion) of the sleeve  400 . The sleeve-side connection part  410  has a cylindrical shape as a whole. The sleeve-side connection part  410  has an engagement recess  412 . The engagement recess  412  is provided on an outer circumferential surface of the sleeve-side connection part  410 . The engagement recess  412  is a circumferential groove. 
     As shown in  FIG. 3 , the spacer  500  has an inner surface  502  and an outer surface  504 . The inner surface  502  forms a sleeve hole. The sectional shape of the inner surface  502  corresponds to the sectional shape of the outer surface  404  of the sleeve  400 . The outer surface  404  of the sleeve  400  is fitted to the inner surface  502 . In other words, the sleeve  400  is fitted inside the spacer  500 . The spacer  500  is not bonded to the sleeve  400 . The spacer  500  merely abuts on the sleeve  400 . 
     The shape of the inner surface  502  corresponds to the shape of the outer surface  404  of the sleeve  400 . The inner surface  502  is a pyramid surface. The inner surface  502  is a four-sided pyramid surface. The sectional shape of the inner surface  502  is a non-circle. The sectional shape of the inner surface  502  is a polygon (regular polygon). The sectional shape of the inner surface  502  is a tetragon. The sectional shape of the inner surface  502  is a square. The area of a figure formed by a sectional line of the inner surface  502  is increased toward the tip side of the shaft  300 . 
     The shape of the outer surface  504  (outer surface of the tip engagement part RT) corresponds to the shape of the reverse-tapered hole  206 . The outer surface  504  is a pyramid surface. The outer surface  504  is a four-sided pyramid surface. The sectional shape of the outer surface  504  is a non-circle. The sectional shape of the outer surface  504  is a polygon (regular polygon). The sectional shape of the outer surface  504  is a tetragon. The sectional shape of the outer surface  504  is a square. The area of a figure formed by a sectional line of the outer surface  504  is increased toward the tip side of the shaft  300 . That is, the spacer  500  has a reverse-tapered shape. The sleeve  400  and the spacer  500  constitute the tip engagement part RT. 
     The golf club  100  has a screw member  600 . The screw member  600  has a screw-side connection part  602  and a male screw part  604 . The screw-side connection part  602  is positioned on the sleeve side (upper side) of the male screw part  604 . The male screw part  604  constitutes a rear end portion (lower end portion) of the screw member  600 . The screw-side connection part  602  can be detachably connected to the sleeve-side connection part  410 . As a result, the screw member  600  can be detachably connected to the sleeve  400 . The connection between the sleeve  400  and the screw member  600  can be easily made. The connection can be achieved by simply pressing the screw member  600  against the sleeve  400 . In other words, the screw member  600  can be connected to the sleeve  400  by a one-touch operation. The connection is automatically completed by simply inserting the sleeve-side connection part  410  to the screw-side connection part  602 . In addition, the connection can be easily released. The screw member  600  can also be easily removed from the sleeve  400 . The details of the connecting mechanism between the sleeve  400  and the screw member  600  will be described later. 
       FIG. 4  shows a procedure of mounting the shaft  300  to the head  200 . 
     In the mounting procedure, an intermediate body  350  is first prepared (step (a) in  FIG. 4 ). The intermediate body  350  has a shaft  300  and a sleeve  400 . In the intermediate body  350 , the sleeve  400  is fixed (bonded) to the tip end portion of the shaft  300 . 
     Next, the sleeve  400  of the intermediate body  350  is made to pass through the hosel hole  204  (step (b) in  FIG. 4 ). The sleeve  400  is made to completely pass through the hosel hole  204 . The sleeve  400  is inserted to the hosel hole  204  from the upper side and is made to come out from the lower side of the hosel hole  204 . The sleeve  400  is moved to a lower side of the sole  210  by the passing (step (b) in  FIG. 4 ). 
     Next, the spacer  500  is attached to the sleeve  400  (step (b) in  FIG. 4 ). The spacer  500  is attached to the sleeve  400  in a state where the sleeve  400  has passed through the hosel hole  204 . The spacer  500  is externally attached to the sleeve  400 . The spacer  500  is attached to externally cover the sleeve  400 . The tip engagement part RT is completed by attaching the spacer  500  to the sleeve  400 . As described later, the spacer  500  has a divided structure. This divided structure makes it possible to attach the spacer  500  externally to the sleeve  400 . 
     Next, the intermediate member  350  is moved to the upper side with respect to the head  200 , whereby the tip engagement part RT (spacer  500 ) is fitted to the reverse-tapered hole  206  (step (c) in  FIG. 4 ). As a result, the shaft  300  is attached to the head  200 . The mounting of the shaft  300  to the head  200  is achieved by the fitting. In other words, an engagement state is achieved by the fitting. The engagement state is a state where the shaft  300  is fixed to the head  200 . In the engagement state, the golf club  100  can be used. In the engagement state, all reverse-tapered fittings are achieved. All reverse-tapered fittings mean: a fitting between the outer surface  404  and the inner surface  502 ; and a fitting between the outer surface  504  and the reverse-tapered hole  206 . 
     Next, the screw member  600  is attached to a head  200  (step (d) in  FIG. 4 ). The screw member  600  is attached to the head  200  from the lower side. The screw member  600  is rotated in a first direction, and is screwed into a female screw part of the head  200 . For the rotation, a tool such as a wrench may be used. The first direction is a direction in which the screw member  600  is fastened. As the screw-connection progresses, the screw member  600  is moved to a direction (the upper side) approaching the hosel hole  204 . With this movement, the screw member  600  presses the tip engagement part RT in an engaging direction (to the upper side). The pressing ensures the above-described engagement state. The pressing makes it possible to eliminate backlash. 
     The screw member  600  has a rotating engagement part  606  for engaging the tool (see  FIG. 2 ). The rotating engagement part  606  is a non-circular hole. 
     Thus, the shaft  300  is easily attached to the head  200 . 
     As described above, the screw member  600  presses the tip engagement part RT. Simultaneously with the pressing, the screw member  600  is connected to the sleeve  400 . When the screw member  600  is moved toward the tip engagement part RT, the sleeve-side connection part  410  is inserted to the screw-side connection part  602  of the screw member  600 . By this insertion, the sleeve-side connection part  410  is automatically connected to the screw-side connection part  602 . As a result, the sleeve  400  is connected to the screw member  600 . 
     The connection between the sleeve  400  and the screw member  600  facilitates the removal of the shaft  300 . To detach the shaft  300  from the head  200 , the above-described procedure is performed in the reverse order. In the reverse procedure, first, the screw member  600  is rotated in a second direction. The second direction is a direction opposite to the first direction. The second direction is a direction in which the screw member  600  is loosened. By this rotation, the screw member  600  is moved to the lower side. The screw member  600  is moved in a direction away from the hosel hole  204 . At this time, the connection between the sleeve  400  and the screw member  600  is maintained. While maintaining the connection between the sleeve  400  and the screw member  600 , the screw member  600  is rotated in the second direction. By this movement, the screw member  600  pulls the tip engagement part RT in an engagement releasing direction. The tip engagement part RT is pulled out from the hosel hole  204  by the screw member  600 . 
     Thus, the shaft  300  can also be removed from the head  200  easily. 
     As described above, in the golf club  100 , the shaft  300  is detachably attached to the head  200 . The shaft  300  can be removed and attached easily. 
       FIG. 5  is a sectional view of the golf club  100  taken along the axial direction.  FIG. 5  is an enlarged sectional view of the vicinity of the tip engagement part RT.  FIG. 6  is a sectional view taken along line A-A in  FIG. 5 . In  FIG. 6 , the hatching is omitted. 
     As shown in  FIG. 5 , the head  200  has a female screw part  220 . The female screw part  220  is coaxial with the reverse-tapered hole  206 . That is, the center line of the female screw part  220  coincides with a center line Z 6  of the reverse-tapered hole  206 . The male screw part  604  of the screw member  600  is screw-connected to the female screw part  220 . The details of the screw-connection will be described later. 
     As described above, in order to press the sleeve  400  in the engaging direction by the screw member  600 , the screw member  600  is rotated in a first direction DR 1 , whereby the screw member  600  is screwed into the female screw part  220  (see  FIG. 5 ). In contrast, in order to pull the sleeve  400  in the engagement releasing direction by the screw member  600 , the screw member  600  is rotated in a second direction DR 2 . 
     In the present embodiment, a center line Z 1  of the inner surface  402  of the sleeve  400  is not inclined with respect to a center line Z 2  of the outer surface  404  of the sleeve  400 . The center line Z 1  conforms to the center line Z 2 . A center line Z 3  of the shaft  300  is not inclined with respect to the center line Z 2  of the outer surface  404  of the sleeve  400 . The center line Z 3  conforms to the center line Z 2 . A center line Z 4  of the inner surface  502  of the spacer  500  is not inclined with respect to a center line Z 5  of the outer surface  504  of the spacer  500 . The center line Z 4  conforms to the center line Z 5 . The center line Z 4  of the inner surface  502  of the spacer  500  is not inclined with respect to a center line Z 6  of the reverse-tapered hole  206  of the head  200 . The center line Z 4  conforms to the center line Z 6 . The center line Z 3  of the shaft  300  is not inclined with respect to the center line Z 6  of the reverse-tapered hole  206  of the head  200 . The center line Z 3  conforms to the center line Z 6 . 
     A double-pointed arrow D 1  in  FIG. 5  shows the minimum width of the hosel hole  204 . In the present embodiment, the sectional shape of the hosel hole  204  is a square, and the minimum width D 1  is the length of one side of the square at the upper end surface of the hosel hole  204 . 
     A double-pointed arrow D 2  in  FIG. 5  shows the maximum width of the sleeve  400 . In the present embodiment, the sectional shape of the outer surface  404  of the sleeve  400  is a square, and the maximum width D 2  is the length of one side of the square at the lower end surface of the sleeve  400 . 
     In the present embodiment, the minimum width D 1  is larger than the maximum width D 2 . In other words, the minimum value of the sectional area of the hosel hole  204  is larger than the maximum value of the sectional area of the sleeve  400 . The lower end of the sleeve  400  can pass through an opening of the upper end of the hosel hole  204 . As a result, the sleeve  400  can pass through the hosel hole  204 . The sleeve  400  can be inserted to the hosel hole  204  from the upper side, pass through the hosel hole  204 , and come out from the lower side of the hosel hole  204 . The thickness of the spacer  500  is set such that the minimum width D 1  is larger than the maximum width D 2 . 
       FIG. 7  is a sectional view of a head having a tip engagement part RTa according to a modification example.  FIG. 7  is a sectional view corresponding to  FIG. 6 . In  FIG. 7 , the hatching is also omitted. The tip engagement part RTa has a sleeve  400   a  and a spacer  500   a . The sleeve  400   a  and the spacer  500   a  constitute the tip engagement part RTa. 
     The sleeve  400   a  has an inner surface  402   a  and an outer surface  404   a . The inner surface  402   a  forms a shaft hole. The sectional shape of the inner surface  402   a  is a circle. The shape of the inner surface  402   a  corresponds to the shape of the outer surface of the shaft  300 . The inner surface  402   a  is fixed to the tip end portion of the shaft  300 . That is, the sleeve  400   a  is fixed to the tip end portion of the shaft  300 . An adhesive is used for the fixation. 
     The outer surface  404   a  is a pyramid surface. The outer surface  404   a  is an eight-sided pyramid surface. The sectional shape of the outer surface  404   a  is a non-circle. The sectional shape of the outer surface  404   a  is a polygon (regular polygon). The sectional shape of the outer surface  404   a  is an octagon. The sectional shape of the outer surface  404   a  is a regular octagon. The area of a figure formed by a sectional line of the outer surface  404   a  is increased toward the tip side of the shaft  300 . That is, the sleeve  400   a  has a reverse-tapered shape. 
     The spacer  500   a  has an inner surface  502   a  and an outer surface  504   a . The inner surface  502   a  forms a sleeve hole. The sectional shape of the inner surface  502   a  corresponds to the sectional shape of the outer surface  404   a  of the sleeve  400   a . The outer surface  404   a  of the sleeve  400   a  is fitted to the inner surface  502   a . In other words, the sleeve  400   a  is fitted inside the spacer  500   a . The spacer  500   a  is not bonded to the sleeve  400   a . The spacer  500   a  is merely brought into contact with the sleeve  400   a.    
     The shape of the inner surface  502   a  corresponds to the shape of the outer surface  404   a  of the sleeve  400   a . The inner surface  502   a  is a pyramid surface. The inner surface  502   a  is an eight-sided pyramid surface. The sectional shape of the inner surface  502   a  is a non-circle. The sectional shape of the inner surface  502   a  is a polygon (regular polygon). The sectional shape of the inner surface  502   a  is an octagon. The sectional shape of the inner surface  502   a  is a regular octagon. The area of a figure formed by a sectional line of the inner surface  502   a  is increased toward the tip side of the shaft  300 . 
     The shape of the outer surface  504   a  (outer surface of the tip engagement part RTa) corresponds to the shape of a reverse-tapered hole. The outer surface  504   a  is a pyramid surface. The outer surface  504   a  is an eight-sided pyramid surface. The sectional shape of the outer surface  504   a  is a non-circle. The sectional shape of the outer surface  504   a  is a polygon (regular polygon). The sectional shape of the outer surface  504   a  is an octagon. The sectional shape of the outer surface  504   a  is a regular octagon. The area of a figure formed by a sectional line of the outer surface  504   a  is increased toward the tip side of the shaft  300 . 
       FIG. 8  is a perspective view of the spacer  500 .  FIG. 9( a )  is a sectional view taken along line A-A in  FIG. 8 . As described above, the spacer  500  has the inner surface  502  and the outer surface  504 . 
     The spacer  500  has a divided structure. The spacer  500  has a first divided body  510  and a second divided body  520 . A divisional line d 1  is shown in  FIG. 8 . The divisional line d 1  is a boundary between the first divided body  510  and the second divided body  520 . 
     The spacer  500  has a connecting part  530 , although not shown in the drawings except  FIG. 8 . In the present embodiment, the connecting part  530  is a plate spring. The plate spring is an elastic body. In the present embodiment, two connecting parts  530  are provided. One side of each of the connecting parts  530  is fixed to the first divided body  510 , and the other side of each of the connecting parts  530  is fixed to the second divided body  520 . 
     The connecting parts  530  are housed in respective recessed parts provided on the outer surface  504 . The connecting parts  530  are not projected outside the outer surface  504 . The connecting parts  530  do not hamper contact between the reverse-tapered hole  206  and the outer surface  504 . 
     Although the step (b) in  FIG. 4  shows that the first divided body  510  and the second divided body  520  are separated from each other, the spacer  500  is actually configured to open and close. The connecting parts  530  play the role of a hinge. The spacer  500  opens on the connecting parts  530 . The spacer  500  opens by applying an external force. This opened state is shown by two-dot chain lines in  FIG. 9( a ) . The spacer  500  opens by bending the connecting parts  530  (plate springs). In this opened state, a gap gp is produced between the first divided body  510  and the second divided body  520 . The sleeve  400  can be put inside the spacer  500  through the gap gp. The spacer  500  is closed in a state where the sleeve  400  is put inside the spacer. The plate springs  530  bias the spacer  500  so that the spacer  500  is in a closed state. Therefore, the spacer  500  is (automatically) closed if the external force is lost. 
     The connecting parts  530  can maintain a connected state in which the first divided body  510  is connected to the second divided body  520 . The spacer  500  is in the connected state when an external force does not act on the spacer  500 . The connected state is a state of the spacer  500  in the golf club  100  usable as a club. 
     The spacer  500  has a position adjusting structure to prevent a positional displacement between the first divided body  510  and the second divided body  520 . As the position adjusting structure, a plate splicing structure may be applied. The embodiment of  FIG. 9( a )  includes an example of the position adjusting structure. In the position adjusting structure, the first divided body  510  has an abutting surface m 1  which prevents the positional displacement in a thickness direction, and an abutting surface m 2  which prevents the positional displacement in an axial direction. Similarly, the second divided body  520  has the abutting surface m 1  which prevents the positional displacement in the thickness direction, and the abutting surface m 2  which prevents the positional displacement in the axial direction. In the spacer  500  in the closed state, the abutting surface m 1  of the first divided body  510  abuts on the abutting surface m 1  of the second divided body  520 , and the abutting surface m 2  of the first divided body  510  abuts on the abutting surface m 2  of the second divided body  520 . Therefore, the positional displacements in the thickness direction and the axial direction are prevented. 
     The spacer  500  can fulfill the function thereof even if the spacer  500  does not have the position adjusting structure because the spacer  500  is fitted to the outer surface of the sleeve, the inner surface of the hosel hole, etc. In comparison between the abutting surfaces m 1  and the abutting surfaces m 2 , the abutting surfaces m 2  which prevent the positional displacement in the axial direction is more effective. This is because the spacer  500  is fitted to the outer surface of the sleeve, the inner surface of the hosel hole, etc., and thus the positional displacement in the thickness direction is less likely to occur. In this respect, the position adjusting structure preferably includes the abutting surfaces m 2  which prevent the positional displacement in the axial direction, and more preferably includes the abutting surfaces m 2  which prevent the positional displacement in the axial direction, and the abutting surfaces m 1  which prevent the positional displacement in the thickness direction. 
     As shown in  FIG. 9( a ) , the divisional line d 1  of the spacer  500  includes a first divisional line d 11  and a second divisional line d 12 . The first divisional line d 11  is a divisional line on which the connecting parts  530  are not present. The second divisional line d 12  is a divisional line on which the connecting parts  530  are present. In  FIG. 9( a ) , the above-described position adjusting structure provided on the first divisional line d 11  is shown. Preferably, the position adjusting structure is provided also on the second divisional line d 12 . 
       FIG. 9( b )  shows another position adjusting structure. In this position adjusting structure, a projection of a first member Pt 1  and a recess of a second member Pt 2  are butted against each other. The center side in a thickness direction of the first member Pt 1  is overlapped with an inner side and an outer side in a thickness direction of the second member Pt 2 . The first member Pt 1  is either one of the first divided body  510  and the second divided body  520 . The second member Pt 2  is the other of the first divided body  510  and the second divided body  520 . 
       FIG. 9( c )  shows another position adjusting structure. In this position adjusting structure, a projection of a first member Pt 1  and a recess of a second member Pt 2  are butted against each other. The section of the projection of the first member Pt 1  is constituted by slopes. The section of the recess of the second member Pt 2  is constituted by slopes. The center side in a thickness direction of the first member Pt 1  is overlapped with an inner side and an outer side in a thickness direction of the second member Pt 2 . The first member Pt 1  is either one of the first divided body  510  and the second divided body  520 . The second member Pt 2  is the other of the first divided body  510  and the second divided body  520 . 
     The position adjusting structures shown in  FIG. 9( b )  and  FIG. 9( c )  can also prevent the positional displacement in the axial direction in addition to the positional displacement in the thickness direction. For example, when such a position adjusting structure as shown in  FIG. 9( b )  or  FIG. 9( c )  is adopted only at a part of the axial direction, an abutting surface capable of preventing the positional displacement in the axial direction can be formed at a termination position of the position adjusting structure. Therefore, the positional displacement in the axial direction can be prevented. 
       FIG. 10  is a perspective view of a spacer  700  according to another modification example. The spacer  700  has an inner surface  702  and an outer surface  704 . 
     The spacer  700  has a divided structure. The spacer  700  has a first divided body  710  and a second divided body  720 . A divisional line d 1  is shown in  FIG. 10 . The divisional line d 1  is a boundary between the first divided body  710  and the second divided body  720 . 
     The spacer  700  has ring-shaped elastic bodies  730  and  740 . The spacer  700  further has circumferential grooves  750  and  760 . The elastic bodies  730  and  740  are fitted to the circumferential grooves  750  and  760 , respectively. The elastic bodies  730  and  740  are not projected outside the outer surface  704 . The elastic bodies  730  and  740  do not hamper contact between the outer surface  704  and a reverse-tapered surface to which the outer surface  704  is fitted. The reverse-tapered surface to which the outer surface  704  is fitted is the reverse-tapered hole of the head or an inner surface of another spacer. The elastic bodies  730  and  740  are an example of a connecting part capable of maintaining a connected state in which the first divided body  710  and the second divided body  720  are connected to each other. 
     The elastic bodies  730  and  740  can be removed by applying an external force to stretch the elastic bodies  730  and  740 . The first divided body  710  and the second divided body  720  can be separated from each other by removing the elastic bodies  730  and  740 . On the contrary, the elastic bodies  730  and  740  can be attached after butting the first divided body  710  and the second divided body  720  against each other. The elastically contractile force of the elastic bodies  730  and  740  biases the divided bodies  710  and  720  so that the two divided bodies  710  and  720  are abutted against each other. For example, this spacer  700  also enables to replace a spacer. 
     Thus, the spacer  500  and the spacer  700  each have the divided structure. The spacer  500  and the spacer  700  each have the first divided body and the second divided body. The spacer  500  and the spacer  700  each have the connecting part capable of maintaining the connected state in which the first divided body is connected to the second divided body. In the spacer  500  and the spacer  700 , the mutual transition between the connected state in which the first divided body and the second divided body are connected to each other, and a separated state in which a gap is formed between the first divided body and the second divided body is enabled. In the separated state, the sleeve can be disposed inside the spacer by allowing the sleeve to pass through the gap. In the separated state, the spacer can be detached from or attached to the shaft  300  to which the sleeve  400  is fixed. 
       FIG. 11  is a sectional view of a golf club  100   b  according to another embodiment.  FIG. 11  is an enlarged sectional view of the vicinity of a tip engagement part RTb. 
     In the present embodiment, a center line Z 1  of an inner surface  402   b  of a sleeve  400   b  is inclined with respect to a center line Z 2  of an outer surface  404   b  of the sleeve  400   b . The inclination angle is θ degree. The center line Z 3  of the shaft  300  is inclined with respect to the center line Z 2  of the outer surface  404   b  of the sleeve  400   b . The inclination angle is θ degree. A center line Z 4  of an inner surface  502   b  of a spacer  500   b  is not inclined with respect to a center line Z 5  of an outer surface  504   b  of the spacer  500   b . The center line Z 4  conforms to the center line Z 5 . The center line Z 4  of the inner surface  502   b  of the spacer  500   b  is not inclined with respect to a center line Z 6  of a reverse-tapered hole  206   b  of a head  200   b . The center line Z 4  conforms to the center line Z 6 . The center line Z 3  of the shaft  300  is inclined with respect to the center line Z 6  of the reverse-tapered hole  206   b . The inclination angle is θ degree. 
     Thus, in the embodiment of  FIG. 11 , the center line Z 1  of the inner surface  402   b  of the sleeve  400   b  is inclined with respect to the center line Z 6  of the reverse-tapered hole  206   b . Therefore, a loft angle and a lie angle can be changed based on a rotation position of the sleeve  400   b . The embodiment of  FIG. 11  has an angle adjusting function. 
     The center line Z 4  of the inner surface  502   b  of the spacer  500   b  may be inclined with respect to the center line Z 5  of the outer surface  504   b  of the spacer  500   b . The inclination between the center line Z 1  of the inner surface  402   b  of the sleeve  400   b  and the center line Z 2  of the outer surface  404   b  is defined as an inclination A, and the inclination between the center line Z 4  of the inner surface  502   b  of the spacer  500   b  and the center line Z 5  of the outer surface  504   b  is defined as an inclination B. The inclination A and the inclination B may be used alone or in combination. This combination enhances the degree of freedom of angle adjustment. 
     Although not shown in the drawings, the sleeve  400   b  also has a sleeve-side connection part. In the present embodiment, the position of the sleeve-side connection part changes because of the inclination. To address the change, a sleeve including an adjustment mechanism in which the sleeve-side connection part is movable with respect to the sleeve body may be used, for example. Such a sleeve will be described later. 
     [Rotation Position of Sleeve] 
     The sleeve can be rotated about the center line of the sleeve itself. The rotation position of the sleeve is changed by the rotation. In the engagement state, the sleeve can take a plurality of rotation positions. The number of the rotation positions which can be taken is set based on the shape of the outer surface of the sleeve. 
     [Rotation Position of Spacer] 
     The spacer can be rotated about the center line of the spacer itself. The rotation position of the spacer is changed by the rotation. In the engagement state, the spacer can take a plurality of rotation positions. The number of the rotation positions which can be taken is set based on the shape of the outer surface of the spacer. 
     [Adjustment of Position and Direction of Center Line of Shaft] 
     The center line of the shaft hole (the center line of the shaft) can be displaced with respect to the center line of the outer surface of the sleeve. These center lines may be inclined with respect to each other, or may be displaced in parallel to each other (parallel and eccentric). Inclination and eccentricity may be combined. In this case, the direction and/or the position of the center line of the shaft can be changed by the rotation position of the sleeve. 
     The center line of the inner surface of the spacer can be displaced with respect to the center line of the outer surface of the spacer. These center lines may be inclined with respect to each other, or may be displaced in parallel to each other (parallel and eccentric). Inclination and eccentricity may be combined. In this case, the direction and/or the position of the center line of the shaft can be changed by the rotation position of the spacer. 
     The rotation position of the spacer can be selected independently of the rotation position of the sleeve. In addition, when a plurality of spacers are used, rotation positions of the respective spacers can be selected independently of each other. The degree of freedom of the adjustment is enhanced by the spacer. The degree of freedom of the adjustment is further enhanced by using a plurality of spacers. In these respects, the number of the spacers which are stacked is preferably one or two or more. In view of complexity of adjustment and downsizing of the hosel part, the number of the spacers which are stacked is preferably one or two. 
       FIG. 12  to  FIG. 17  are plan views showing the position of a lower end surface of the tip engagement part. The illustration of the sleeve-side connection part is omitted in these plan views. Changes in the position and the direction of the center line of the shaft will be explained using these plan views. 
     In  FIG. 12  to  FIG. 17 , the following abbreviations are used.
         LI: lie angle   LF: loft angle   FP: face progression   DC: distance of the center of gravity   L: large   M: medium   S: small       

       FIG. 12  to  FIG. 15  show an embodiment A in which the number of the spacers is one. In this embodiment, a sleeve sv 1  and a spacer sp 1  are used. A position Zs of the center line of the shaft at the lower end of the hosel hole is shown by the intersection point of solid lines. The intersection point of one-dot chain lines shows a position of the center line of the shaft at the upper end of the hosel hole. In this embodiment, the position of the center line of the shaft at the upper end of the hosel hole is not changed regardless of the rotation positions of the sleeve sv 1  and the spacer sp 1 . 
     The embodiment A shown in  FIG. 12  to  FIG. 15  satisfies the following (A1) and (A2). 
     (A1) A center line of an inner surface of the sleeve sv 1  (that is, the center line of the shaft) is inclined with respect to a center line of an outer surface of the sleeve sv 1 . 
     (A2) A center line of an inner surface of the spacer sp 1  is inclined with respect to a center line of an outer surface of the spacer sp 1 . 
     In the embodiment A, the outer surface of the sleeve sv 1  is a four-sided pyramid surface, each of the inner surface and the outer surface of the spacer sp 1  is also a four-sided pyramid surface, and a reverse-tapered hole is also a four-sided pyramid surface. Therefore, the number of the rotation positions of the sleeve sv 1  is four, and the number of the rotation positions of the spacer sp 1  is also four. In the embodiment A, the number of kinds of combinations of the rotation positions of the sleeve sv 1  and the rotation positions of the spacer sp 1  is: 4×4=16. A golf club according to the embodiment A is excellent in degree of freedom of adjustment.  FIG. 12  to  FIG. 15  show all the 16 kinds of combinations. 
     In state (a) of  FIG. 12 , the rotation position of the sleeve sv 1  is a first position, and the rotation position of the spacer sp 1  is a first position. In state (b) of  FIG. 12 , the rotation position of the sleeve sv 1  is a second position, and the rotation position of the spacer sp 1  is the first position. In state (c) of  FIG. 12 , the rotation position of the sleeve sv 1  is a third position, and the rotation position of the spacer sp 1  is the first position. In state (d) of  FIG. 12 , the rotation position of the sleeve sv 1  is a fourth position, and the rotation position of the spacer sp 1  is the first position. 
     In state (a) of  FIG. 13 , the rotation position of the sleeve sv 1  is the first position, and the rotation position of the spacer sp 1  is a second position. In state (b) of  FIG. 13 , the rotation position of the sleeve sv 1  is the second position, and the rotation position of the spacer sp 1  is a second position. In state (c) of  FIG. 13 , the rotation position of the sleeve sv 1  is the third position, and the rotation position of the spacer sp 1  is the second position. In state (d) of  FIG. 13 , the rotation position of the sleeve sv 1  is the fourth position, and the rotation position of the spacer sp 1  is the second position. 
     In state (a) of  FIG. 14 , the rotation position of the sleeve sv 1  is the first position, and the rotation position of the spacer sp 1  is a third position. In state (b) of  FIG. 14 , the rotation position of the sleeve sv 1  is the second position, and the rotation position of the spacer sp 1  is the third position. In state (c) of  FIG. 14 , the rotation position of the sleeve sv 1  is the third position, and the rotation position of the spacer sp 1  is the third position. In state (d) of  FIG. 14 , the rotation position of the sleeve sv 1  is the fourth position, and the rotation position of the spacer sp 1  is the third position. 
     In state (a) of  FIG. 15 , the rotation position of the sleeve sv 1  is the first position, and the rotation position of the spacer sp 1  is a fourth position. In state (b) of  FIG. 15 , the rotation position of the sleeve sv 1  is the second position, and the rotation position of the spacer sp 1  is the fourth position. In state (c) of  FIG. 15 , the rotation position of the sleeve sv 1  is the third position, and the rotation position of the spacer sp 1  is the fourth position. In state (d) of  FIG. 15 , the rotation position of the sleeve sv 1  is the fourth position, and the rotation position of the spacer sp 1  is the fourth position. 
     These 16 kinds of combinations include 9 kinds of positions Zs. That is, the center line of the shaft can take nine different positions. 
     In  FIG. 12  to  FIG. 15 , the transverse direction of the drawing is a face-back direction. The right side of the drawing is a face side, and the left side of the drawing is a back side. As the position Zs is closer to the rightmost side, the loft angle is smaller. As the position Zs is closer to the leftmost side, the loft angle is larger. The golf club according to the present embodiment is right-handed. 
     In  FIGS. 12 to 15 , the lengthwise direction of the drawing is a toe-heel direction. The upper side of the drawing is a toe side, and the lower side of the drawing is a heel side. As the position Zs is closer to the uppermost side, the lie angle is smaller. As the position Zs is closer to the lowermost side, the lie angle is larger. 
     According to the 9 kinds of positions of the center line of the shaft, specifications of the combinations of the loft angles and the lie angles are the following 9 kinds. 
     (Specification 1) The lie angle is small and the loft angle is small. 
     (Specification 2) The lie angle is small and the loft angle is medium. 
     (Specification 3) The lie angle is small and the loft angle is large. 
     (Specification 4) The lie angle is medium and the loft angle is small. 
     (Specification 5) The lie angle is medium and the loft angle is medium. 
     (Specification 6) The lie angle is medium and the loft angle is large. 
     (Specification 7) The lie angle is large and the loft angle is small. 
     (Specification 8) The lie angle is large and the loft angle is medium. 
     (Specification 9) The lie angle is large and the loft angle is large. 
     In the golf club according to the embodiment A, an independent variability of the loft angle is achieved. In the golf club according to the embodiment A, an independent variability of the lie angle is achieved. In the embodiment A, the direction (phase) of the reverse-tapered hole (hosel hole) is set so that the independent variability of the loft angle and the independent variability of the lie angle are achieved. 
     For example, among the specifications 1, 2, and 3, the loft angle is changed without changing the lie angle. This is one example of the independent variability of the loft angle. The same independent variability is provided also among the specifications 4, 5, and 6. The same independent variability is provided also among the specifications 7, 8, and 9. 
     For example, among the specifications 1, 4, and 7, the lie angle is changed without changing the loft angle. This is one example of the independent variability of the lie angle. The same independent variability is provided also among the specifications 2, 5, and 8. The same independent variability is provided also among the specifications 3, 6, and 9. 
     The independent variability of the loft angle means that the loft angle is changed without substantially changing the lie angle. The phrase “without substantially changing” means that change in the lie angle is equal to or less than 20% based on the amount of change in the loft angle. The independent variability of the lie angle means that the lie angle is changed without substantially changing the loft angle. The phrase “without substantially changing” means that change in the loft angle is equal to or less than 20% based on the amount of change in the lie angle. 
       FIG. 16  and  FIG. 17  show an embodiment B in which the number of the spacers is 2 (double-layered). In the present embodiment, a sleeve sv 1 , a first spacer sp 1 , and a second spacer sp 2  are used. A position Zs of the center line of the shaft at the lower end of the hosel hole is shown by the intersection point of thick solid lines. The intersection point of one-dot chain lines shows the position of the center line of the outer surface of the sleeve sv 1  at the lower end of the hosel hole. The intersection point of thin solid lines shows the position of the center line of the outer surface of the spacer sp 1  at the lower end of the hosel hole. The intersection point of dashed lines shows the position of the center line of the outer surface of the spacer sp 2  at the lower end of the hosel hole. Regardless of the rotation positions of the sleeve sv 1 , the spacer sp 1 , and the spacer sp 2 , the three center lines cross at one point at the position of the upper end of the hosel hole. 
     In the embodiment B, the outer surface of the sleeve sv 1  is a four-sided pyramid surface. Each of inner and outer surfaces of the first spacer sp 1  is also a four-sided pyramid surface, and each of inner and outer surfaces of the second spacer sp 2  is also a four-sided pyramid surface. A reverse-tapered hole is also a four-sided pyramid surface. Therefore, the number of the rotation positions of the sleeve sv 1  is four, the number of the rotation positions of the first spacer sp 1  is also four, and the number of the rotation positions of the second spacer sp 2  is also four. In the embodiment B, the number of kinds of combinations of the three members&#39; rotation positions is 4×4×4=64. A golf club according to the embodiment B has an excellent degree of freedom of adjustment. 
     The embodiment B shown in  FIG. 16  and  FIG. 17  satisfies the following (B1) to (B3). 
     (B1) A center line of an inner surface of the sleeve sv 1  (that is, the center line of the shaft) is parallel and eccentric to a center line of the outer surface of the sleeve sv 1 . 
     (B2) A center line of the inner surface of the first spacer sp 1  is inclined with respect to a center line of the outer surface of the first spacer sp 1 . 
     (B3) A center line of the inner surface of the second spacer sp 2  is inclined with respect to a center line of the outer surface of the second spacer sp 2 . 
     The phrase “parallel and eccentric” means eccentricity in which center lines are parallel to each other. 
     The relation between the first spacer sp 1  and the second spacer sp 2  in the embodiment B is the same as the relation between the sleeve sv 1  and the spacer sp 1  in the above-mentioned embodiment A. Therefore, 9 kinds of combinations of the loft angles and the lie angles are achieved by the first spacer sp 1  and the second spacer sp 2 . Furthermore, in the embodiment B, adjustment because of the sleeve sv 1  is added. Since the sleeve sv 1  is parallel and eccentric, each of the nine positions of the shaft axis can be further moved in parallel. The parallel movement of the shaft axis can change face progression. The parallel movement can achieve the movement of the shaft axis in the face-back direction. Furthermore, the parallel movement can achieve the movement of the shaft axis in the toe-heel direction. In the embodiment B, the degree of freedom of adjustment of the shaft axis is further improved by the two spacers. 
       FIG. 16  and  FIG. 17  show only eight kinds of the above-mentioned 64 kinds. 
     In states (a) to (d) in  FIG. 16 , the rotation position of the first spacer sp 1  is a first position, and the rotation position of the second spacer sp 2  is also the first position. In states (a) to (d) in  FIG. 16 , only the rotation position of the sleeve sv 1  is changed without changing the rotation positions of the first spacer sp 1  and the second spacer sp 2 . In state (a) in  FIG. 16 , the rotation position of the sleeve sv 1  is a first position. In state (b) in  FIG. 16 , the rotation position of the sleeve sv 1  is a second position. In state (c) in  FIG. 16 , the rotation position of the sleeve sv 1  is a third position. In state (d) in  FIG. 16 , the rotation position of the sleeve sv 1  is a fourth position. 
     In states (a) to (d) in  FIG. 17 , the rotation position of the first spacer sp 1  is the second position, and the rotation position of the second spacer sp 2  is the first position. Also in states (a) to (d) in  FIG. 17 , only the rotation position of the sleeve sv 1  is changed without changing the rotation positions of the first spacer sp 1  and the second spacer sp 2 . In state (a) in  FIG. 17 , the rotation position of the sleeve sv 1  is the first position. In state (b) in  FIG. 17 , the rotation position of the sleeve sv 1  is the second position. In state (c) in  FIG. 17 , the rotation position of the sleeve sv 1  is the third position. In state (d) in  FIG. 17 , the rotation position of the sleeve sv 1  is the fourth position. 
     In comparing  FIG. 16  with  FIG. 17 , in states (a) to (d) in  FIG. 16 , the rotation position of the first spacer sp 1  is the first position, in contrast, in states (a) to (d) in  FIG. 17 , the rotation position of the first spacer sp 1  is the second position. Because of the difference, the loft angle in each of states (a) to (d) in  FIG. 17  is decreased to medium as compared with the large loft angle in each of states (a) to (d) in  FIG. 16 . 
     In states (a) to (d) in  FIG. 16 , the rotation position of the sleeve sv 1  changes from the first position to the fourth position. Because of the change, face progression (FP), which is an index showing the position of the center line of the shaft in the face-back direction, changes in order from large (L), medium (M), small (S), to medium (M). Simultaneously, the distance of the center of gravity which is an index showing the position of the center line of the shaft in the toe-heel direction changes in order from medium (M), small (S), medium (M), to large (L). The distance of the center of gravity is a distance between the center of gravity of the head and the center line of the shaft. The distance is measured in an image projected to a plane which is parallel to the toe-heel direction and includes the center line of the shaft. 
     Therefore, for example, in comparison between state (a) and state (c) in  FIG. 16 , the position of the center line of the shaft (the position of the center line of the shaft at the upper end of the hosel hole) moves in the face-back direction while maintaining the inclination of the center line of the shaft so that the lie angle is small and the loft angle is large. In addition, in state (a) and state (c) of  FIG. 16 , the distance of the center of gravity is medium without change. 
     In comparison between state (b) and state (d) in  FIG. 16 , the position of the center line of the shaft (the position of the center line of the shaft at the upper end of the hosel hole) moves in the toe-heel direction while maintaining the inclination of the center line of the shaft so that the lie angle is small and the loft angle is large. In addition, in state (b) and state (d) of  FIG. 16 , the face progression is medium without change. 
     Also in states (a) to (d) in  FIG. 17 , the rotation position of the sleeve sv 1  changes from the first position to the fourth position. Because of the change, the face progression changes in order from large, medium, small, to medium. Simultaneously, the distance of the center of gravity changes in order from medium, small, medium, to large. 
     Therefore, for example, in comparison between state (a) and state (c) in  FIG. 17 , the position of the center line of the shaft (the position of the center line of the shaft at the upper end of the hosel hole) moves in the face-back direction while maintaining the inclination of the center line of the shaft so that the lie angle is small and the loft angle is medium. In addition, in state (a) and state (c) of  FIG. 17 , the distance of the center of gravity is medium without change. 
     In comparison between state (b) and state (d) in  FIG. 17 , the position of the center line of the shaft (the position of the center line of the shaft at the upper end of the hosel hole) moves in the toe-heel direction while maintaining the inclination of the center line of the shaft so that the lie angle is small and the loft angle is medium. In addition, in state (b) and state (d) of  FIG. 17 , the face progression is medium without change. 
     Although the axis displacement of the sleeve sv 1  is parallel eccentricity in the present embodiment, the axis displacement may be naturally inclination, for example. Of course, parallel eccentricity may be adopted for the spacer. 
     As shown in  FIG. 12  to  FIG. 17 , the position of the center line of the shaft on the sole side can be variously changed. Since the present embodiment eliminates the need for screw fixation, the degrees of freedom of the position and the inclination of the center line of the shaft are high. Therefore, the range of angle adjustment can be increased. The range of adjustment for the loft angle, the lie angle, the face angle, the face progression, etc., can be increased. 
     Each of nine drawings shown in  FIG. 18  is a plan view (drawing viewed from above) of the sleeve which can be applied to the present embodiment. In  FIG. 18 , examples of the sectional shape of the outer surface of the sleeve include a tetragon (square), a hexagon (regular hexagon), and an octagon (regular octagon). Axis coincidence, axis parallel eccentricity, and axis inclination are shown as the form of the axis displacement of the sleeve in  FIG. 18 . 
     In a sleeve sv 11 , the sectional shape of the outer surface of the sleeve is tetragon (square); the outer surface of the sleeve is a four-sided pyramid surface; and the center line of the inner surface of the sleeve (the center line of the shaft) coincides with the center line of the outer surface of the sleeve. In a sleeve sv 12 , the sectional shape of the outer surface of the sleeve is a hexagon (regular hexagon); the outer surface of the sleeve is a six-sided pyramid surface; and the center line of the inner surface of the sleeve (the center line of the shaft) coincides with the center line of the outer surface of the sleeve. In a sleeve sv 13 , the sectional shape of the outer surface of the sleeve is an octagon (regular octagon); the outer surface of the sleeve is an eight-sided pyramid surface; and the center line of the inner surface of the sleeve (the center line of the shaft) coincides with the center line of the outer surface of the sleeve. 
     In a sleeve sv 14 , the sectional shape of the outer surface of the sleeve is a tetragon (square); the outer surface of the sleeve is a four-sided pyramid surface; and the center line of the inner surface of the sleeve (the center line of the shaft) is parallel and eccentric to the center line of the outer surface of the sleeve. In a sleeve sv 15 , the sectional shape of the outer surface of the sleeve is a hexagon (regular hexagon); the outer surface of the sleeve is a six-sided pyramid surface; and the center line of the inner surface of the sleeve (the center line of the shaft) is parallel and eccentric to the center line of the outer surface of the sleeve. In a sleeve sv 16 , the sectional shape of the outer surface of the sleeve is an octagon (regular octagon); the outer surface of the sleeve is an eight-sided pyramid surface; and the center line of the inner surface of the sleeve (the center line of the shaft) is parallel and eccentric to the center line of the outer surface of the sleeve. 
     In a sleeve sv 17 , the sectional shape of the outer surface of the sleeve is a tetragon (square); the outer surface of the sleeve is a four-sided pyramid surface; and the center line of the inner surface of the sleeve (the center line of the shaft) is inclined with respect to the center line of the outer surface of the sleeve. In a sleeve sv 18 , the sectional shape of the outer surface of the sleeve is a hexagon (regular hexagon); the outer surface of the sleeve is a six-sided pyramid surface; and the center line of the inner surface of the sleeve (the center line of the shaft) is inclined with respect to the center line of the outer surface of the sleeve. In a sleeve sv 19 , the sectional shape of the outer surface of the sleeve is an octagon (regular octagon); the outer surface of the sleeve is an eight-sided pyramid surface; and the center line of the inner surface of the sleeve (the center line of the shaft) is inclined with respect to the center line of the outer surface of the sleeve. 
     Thus, various sleeves may be used. Of course, these sleeves shown in  FIG. 18  are merely exemplified. Similarly, various forms may be adopted also for the spacer. 
     From the viewpoint of preventing an excessively large hosel, the amount of eccentricity of parallel eccentricity in the sleeve is preferably equal to or less than 5 mm, more preferably equal to or less than 2 mm, and still more preferably equal to or less than 1.5 mm. From the viewpoint of adjusting properties, the amount of eccentricity of parallel eccentricity in the sleeve is preferably equal to or greater than 0.5 mm, and more preferably equal to or greater than 1.0 mm. 
     From the viewpoint of preventing an excessively large hosel, the inclination angle θ 1  of the center line of the shaft with respect to the center line of the outer surface of the sleeve is preferably equal to or less than 5 degrees, more preferably equal to or less than 3 degrees, and still more preferably equal to or less than 2 degrees. From the viewpoint of adjusting properties, the inclination angle θ 1  is preferably equal to or greater than 0.5 degrees, more preferably equal to or greater than 1 degree, and still more preferably equal to or greater than 1.5 degrees. 
     From the viewpoint of preventing an excessively large hosel, the amount of eccentricity of parallel eccentricity in the spacer is preferably equal to or less than 5 mm, more preferably equal to or less than 2 mm, and still more preferably equal to or less than 1.5 mm. From the viewpoint of adjusting properties, the amount of eccentricity of parallel eccentricity in the spacer is preferably equal to or greater than 0.5 mm, and more preferably equal to or greater than 1.0 mm. 
     From the viewpoint of preventing an excessively large hosel, the inclination angle θ 2  of the center line of the inner surface of the spacer with respect to the center line of the outer surface of the spacer is preferably equal to or less than 5 degrees, more preferably equal to or less than 3 degrees, and still more preferably equal to or less than 2 degrees. From the viewpoint of adjusting properties, the inclination angle θ 2  is preferably equal to or greater than 0.5 degrees, more preferably equal to or greater than 1 degree, and still more preferably equal to or greater than 1.5 degrees. 
     An engagement releasing direction and an engaging direction are defined in the present application. In the present application, the engagement releasing direction is a direction in which the tip engagement part RT moves toward the sole side with respect to the reverse-tapered hole  206 . In other words, the engagement releasing direction means a direction in which the reverse-tapered hole  206  moves toward the grip side with respect to the tip engagement part RT. If the tip engagement part RT is moved in the engagement releasing direction, the tip engagement part RT comes out of the reverse-tapered hole  206 . On the other hand, the engaging direction in the present application means a direction in which the tip engagement part RT moves toward the grip side with respect to the reverse-tapered hole  206 . In other words, the engaging direction means a direction in which the reverse-tapered hole  206  moves toward the sole side with respect to the tip engagement part RT. 
     In the golf club in the engagement state, the reverse-tapered fitting is formed between the tip engagement part RT and the reverse-tapered hole  206 . A force in the engaging direction cannot release the reverse-tapered fitting, and on the contrary, enhances the contact pressure of the reverse-tapered fitting. The force in the engaging direction further ensures the engagement between the tip engagement part RT and the reverse-tapered hole  206 . 
     A large force acting on the head is a centrifugal force during swinging, and an impact shock force upon impact. Of the forces, the centrifugal force is the above-mentioned force in the engaging direction. Because of a loft angle of the head, a component force of the impact shock force in the axial direction is also the force in the engaging direction. Therefore, the centrifugal force and the impact shock force cannot release the engagement between the tip engagement part RT and the reverse-tapered hole  206 , and further ensures the engagement conversely. Since each of the tip engagement part RT and the reverse-tapered hole  206  has a non-circular sectional shape, relative rotation between the two cannot occur. As a result, although the tip engagement part RT and the reverse-tapered hole  206  are not fixed by an adhesive or the like, retention and anti-rotation required as a golf club are achieved. The structure of the reverse-tapered fitting can achieve both holding properties and attaching/detaching easiness. 
     Therefore, the screw member  600  is not necessarily needed. 
     However, the result of the studies made by the inventor has demonstrated the effectiveness of the screw member  600 . It has been found that high dimensional accuracy is required to bring the outer surface of the tip engagement part RT into complete surface-contact with the inner surface of the hosel hole  204 . It has been found that even a slight dimensional error could cause backlash. The backlash results in a sense of discomfort during hitting. 
     It has been found that as a result of the screw member  600  pressing the tip engagement part RT in the engaging direction, elastic deformation occurs in the tip engagement part RT and/or the hosel hole  204 , thus eliminating the backlash. 
     Furthermore, the inventor has found another effect of the screw member  600 . The tip engagement part RT pressed by the screw member  600  is firmly engaged with the hosel hole  204  with elastic deformation. It has been found that the tip engagement part RT that has been fitted with elastic deformation is less likely to come out from the hosel hole  204 . As described above, the sleeve  400  is connected to the screw member  600 , and therefore, moves together with the screw member  600 . When the screw member  600  is moved to the lower side as the screw-connection is released, the sleeve  400  is pulled to the lower side. As a result, by simply rotating the screw member  600  in the second direction DR 2 , the tip engagement part RT is pulled to the lower side, and is pulled out from the hosel hole  204 . Thus, the screw member  600  facilitates the removal of the shaft  300 . 
     In situations other than swinging, a force in the engagement releasing direction may act on the golf club. Examples of the situations include a state where the golf club is inserted into a golf bag. In this state, the golf club is stood with the head up. In this case, the gravity acting on the head acts as the force in the engagement releasing direction. The screw member  600  can prevent the falling-off of the head. 
     From the viewpoint of the Golf Rules, the screw member  600  is preferably configured so as not to be rotated by bare hands. From the viewpoint of the Golf Rules, it is preferable that a special tool is required for rotating the screw member  600 . 
     The golf club may be configured such that its club length can be adjusted. For example, a plurality of spacers having different wall thicknesses may be prepared. By replacing the spacer, the wall thickness of the spacer is changed, and the axial direction position of the tip engagement part RT is changed. Therefore, the club length can be adjusted. In this case, extending the axial installation range of the female screw part enables the screw member to follow the change of the axial direction position of the tip engagement part RT. 
       FIG. 19  is sectional views of a golf club  1600  according to another embodiment. In the golf club  1600 , the club length can be changed without replacing a spacer. 
       FIG. 19  shows two states of the golf club  1600 . A state (a) in  FIG. 19  shows a first state of the golf club  1600 . A state (b 1 ) in  FIG. 19  shows a second state of the golf club  1600 . The club length of the golf club  1600  in the first state is shorter than the club length of the golf club  1600  in the second state. In the golf club  1600 , two kinds of length can be selected. 
       FIG. 20  is sectional views at a tip engagement part RT of the golf club  1600 , which illustrates a length adjustment mechanism. 
     A state (a) in  FIG. 20  is a sectional view in the first state (short state). As shown in the state (a) of  FIG. 20 , the tip engagement part RT of the golf club  1600  includes a sleeve  1700  and a spacer  1800 . 
     The sleeve  1700  has a sleeve-side connection part  1710 . The structure of the sleeve-side connection part  1710  is the same as that of the above-described sleeve-side connection part  410 . The sleeve  1700  is bonded to the tip end portion of the shaft  300 . In the golf club  1600 , the above-described screw member  600  is also used. 
     The spacer  1800  has a divided structure. The sleeve  1700  can be made to pass through a hosel hole (not shown in the drawing). The golf club  1600  can be assembled by the procedure shown in  FIG. 4 . 
     As shown in  FIG. 19 , the inner surface of the spacer  1800  has a first abutting face S 1  and the second abutting face S 2 . 
     A plurality of (four) first abutting faces S 1  are provided on the inner surface of the spacer  1800 . A plurality of (four) second abutting faces S 2  are provided on the inner surface of the spacer  1800 . The first abutting faces S 1  and the second abutting faces S 2  are alternately arranged. In the present embodiment, the number of the first abutting faces S 1  is four, and the number of the second abutting faces S 2  is four. The sum of the number of the first abutting faces S 1  and the number of the second abutting faces S 2  is eight. 
     As shown in the state (a) of  FIG. 19 , the first abutting faces S 1  coincide with respective alternate sides of a regular polygon (regular octagon). The regular polygon (regular octagon) coinciding with the first abutting faces S 1  is defined as a first virtual regular polygon (not shown in the drawing). As shown in the state (a) in  FIG. 19 , the second abutting faces S 2  coincide with respective alternate sides of a regular polygon (regular octagon). The regular polygon (regular octagon) coinciding with the second abutting faces S 2  is defined as a second virtual regular polygon (not shown in the drawing). 
     A radial direction position of the second abutting faces S 2  is outside with respect to a radial direction position of the first abutting faces S 1 . The first virtual regular polygon (virtual regular octagon) is smaller than the second virtual regular polygon (virtual regular octagon). The first virtual regular polygon (virtual regular octagon) and the second virtual regular polygon (virtual regular octagon) have the common central point and the same phase. 
     Thus, the first abutting faces S 1  and the second abutting faces S 2  are alternately arranged along respective sides of a regular polygon (regular octagon), and the radial direction position of the first abutting faces S 1  is (slightly) inside of the radial direction position of the second abutting faces S 2 . A step surface S 3  is formed on each boundary between the first abutting faces S 1  and the second abutting faces S 2 . The step surface S 3  may not be present. 
     As shown in the state (a) in  FIG. 19 , the outer surface of the sleeve  1700  includes an abutting engagement face T 1  and a non-abutting engagement face T 2 . 
     A plurality of (four) abutting engagement faces T 1  are provided on the outer surface of the sleeve  1700 . A plurality of (four) non-abutting engagement faces T 2  are provided on the outer surface of the sleeve  1700 . The abutting engagement faces T 1  and the non-abutting engagement faces T 2  are alternately arranged. In the present embodiment, the number of the abutting engagement faces T 1  is four, and the number of the non-abutting engagement faces T 2  is four. The sum of the number of the abutting engagement faces T 1  and the number of the non-abutting engagement faces T 2  is eight. 
     As shown in the state (a) in  FIG. 19 , the abutting engagement faces T 1  coincide with respective alternate sides of a regular polygon (regular octagon). The regular polygon (regular octagon) coinciding with the abutting engagement faces T 1  is defined as a third virtual regular polygon (not shown in the drawing). As shown in the state (a) in  FIG. 19 , the non-abutting engagement faces T 2  coincide with respective alternate sides of a regular polygon (regular octagon). The regular polygon (regular octagon) coinciding with the non-abutting engagement faces T 2  is defined as a fourth virtual regular polygon (not shown in the drawing). 
     A radial direction position of the abutting engagement faces T 1  is outside with respect to a radial direction position of the non-abutting engagement faces T 2 . Therefore, the third virtual regular polygon (virtual regular octagon) is greater than the fourth virtual regular polygon (virtual regular octagon). The third virtual regular polygon (virtual regular octagon) and the fourth virtual regular polygon (virtual regular octagon) have the common central point and the same phase. 
     Thus, the abutting engagement faces T 1  and the non-abutting engagement faces T 2  are alternately arranged along respective sides of a regular polygon (regular octagon), and the radial direction position of the abutting engagement faces T 1  is (slightly) outside of the radial direction position of the non-abutting engagement faces T 2 . A step surface T 3  is formed on each boundary between the abutting engagement faces T 1  and the non-abutting engagement faces T 2 . The step surface T 3  may not be present. 
     The state (a) in  FIG. 19  is a sectional view in the first state (a state where the club length is short). In the first state, the sleeve  1700  is set on a first rotation position. 
     In the first state, the abutting engagement faces T 1  abut on the respective first abutting faces S 1 . In the first state, the abutting engagement faces T 1  are opposed to the respective first abutting faces S 1 , and the non-abutting engagement faces T 2  are opposed to the respective second abutting faces S 2 . While the abutting engagement faces T 1  abut on the respective first abutting faces S 1 , the non-abutting engagement faces T 2  do not abut on the respective second abutting faces S 2 . A gap is formed each between the non-abutting engagement faces T 2  and the respective second abutting faces S 2 . 
     A state (b 1 ) in  FIG. 19  is a sectional view showing a shifting state for shifting to the second state. In the state (b 1 ) of  FIG. 19 , the sleeve  1700  is set on a second rotation position. 
     The shifting state for shifting to the second state means a state in which the sleeve  1700  is rotated by a predetermined angle θ (45 degrees) without changing the axial direction position of the sleeve  1700  with respect to the spacer  1800 . The shifting state is depicted in order to facilitate the understanding of the length adjustment mechanism. When the rotation of the predetermined angle θ is actually performed, the rotation can be made after once moving the tip engagement part RT in the engagement releasing direction. The rotation position of the sleeve  1700  is shifted to the second rotation position from the first rotation position by rotating the sleeve  1700  by the predetermined angle θ. 
     In the shifting state, the abutting engagement faces T 1  are opposed to the respective second abutting faces S 2 , and the non-abutting engagement faces T 2  are opposed to the respective first abutting faces S 1 . In this state, the abutting engagement faces T 1  do not abut on the respective second abutting faces S 2 . As a matter of course, the non-abutting engagement faces T 2  do not abut on the respective first abutting faces S 1 , either. A width of each gap gp between the abutting engagement face T 1  and the second abutting face S 2  is smaller than a width of each gap between the non-abutting engagement face T 2  and the first abutting face S 1 . 
     The fact that the abutting engagement faces T 1  do not abut on the respective second abutting faces S 2  in the state (b 1 ) (shifting state) of  FIG. 19  indicates the feasibility of two kinds of club lengths. That is, the gap gp realizes a second club length (greater club length). This point is explained below by using  FIG. 20 . 
     A state (a) in  FIG. 20  is a sectional view taken along line A-A in the state (a) of  FIG. 19 . A state (b 1 ) in  FIG. 20  is a sectional view taken along line B-B in the state (b 1 ) of  FIG. 19 . As also shown in the state (b 1 ) in  FIG. 20 , in the shifting state, a gap gp is present between the abutting engagement faces T 1  and the respective second abutting faces S 2 . For eliminating the gap to make the abutting engagement faces T 1  abut on the respective second abutting faces S 2 , the shaft  300  to which the sleeve  1700  is fixed should be moved to the axial-direction upper side. That is, the abutting engagement faces T 1  abut on the respective second abutting faces S 2  by moving the sleeve  1700  in the shifting state to the axial-direction upper side with respect to the spacer  1800 . As a result, the second state is realized. A state (b 2 ) in  FIG. 20  shows the second state. 
     As described above, in the golf club  1600 , the axial direction position of the sleeve  1700  with respect to the spacer  1800  in the first state is different from that of the second state. The first state in which the club length is short and the second state in which the club length is long are realized by the difference. In the golf club  1600 , a mutual shifting between the first state and the second state is enabled by rotating the sleeve  1700  with respect to the spacer  1800 . 
     Extending the axial installation range of the female screw part enables the screw member to follow the change of the axial direction position of the sleeve-side connection part  1710 . 
     Thus, in the present embodiment, the sleeve  1700  having a reverse-tapered outer surface and the spacer  1800  having a reverse-tapered inner surface are used. Either one of the reverse-tapered outer surface and the reverse-tapered inner surface includes the abutting engagement faces T 1 . The other of the reverse-tapered outer surface and the reverse-tapered inner surface includes the first abutting faces S 1  and the second abutting faces S 2 . The first state in which the abutting engagement faces T 1  abut on the respective first abutting faces S 1  is formed when the reverse-tapered outer surface is set on the first rotation position. In addition, the second state in which the abutting engagement faces T 1  abut on the respective second abutting faces S 2  is formed when the reverse-tapered outer surface is set on the second rotation position. An axial direction position of the reverse-tapered outer surface with respect to the reverse-tapered inner surface in the first state is different from that of the second state, and a club length is adjusted by the difference. Preferably, the reverse-tapered outer surface includes the non-abutting engagement faces T 2  in addition to the abutting engagement faces T 1 . Preferably, the reverse-tapered outer surface is a pyramid outer surface, and the abutting engagement faces and the non-abutting engagement faces are alternately arranged on the pyramid outer surface. Preferably, the radial direction position of the abutting engagement faces is located outside with respect to the radial direction position of the non-abutting engagement faces. Preferably, the reverse-tapered inner surface may be a pyramid inner surface corresponding to the pyramid outer surface, and the first abutting faces and the second abutting faces are alternately arranged on the pyramid inner surface. Preferably, the pyramid outer surface is an eight-sided pyramid surface. Preferably, the pyramid inner surface is an eight-sided pyramid surface. 
       FIG. 21  is a perspective view of a sleeve  2000  according to another embodiment.  FIG. 22( a )  is a plan view of the sleeve  2000 .  FIG. 22( b )  is a sectional view taken along line B-B in  FIG. 21 .  FIG. 22( c )  is a sectional view taken along line C-C in  FIG. 21 .  FIG. 22( d )  is a bottom view of the sleeve  2000 . 
     The sleeve  2000  has an inner surface  2002 , an outer surface  2004 , an upper end surface  2006  and a lower end surface  2008 . The inner surface  2002  is a circumferential surface. A shaft is bonded to the inner surface  2002 . 
     The sleeve  2000  further has a sleeve-side connection part  2009 . The configuration of the sleeve-side connection part  2009  is the same as that of the above-described sleeve-side connection part  410 . 
     In the present embodiment, the above-described screw member  600  is also used. The screw member  600  can be connected to the sleeve-side connection part  2009 . 
     The outer surface  2004  has reverse-tapered engagement faces K 1 . The reverse-tapered engagement faces K 1  are arranged at a plurality of positions in the circumferential direction. The reverse-tapered engagement faces K 1  are arranged at equal intervals in the circumferential direction. The reverse-tapered engagement faces K 1  are arranged at intervals of a predetermined angle (90 degree) in the circumferential direction. 
     The outer surface  2004  has non-engagement faces K 2 . The non-engagement faces K 2  are arranged at a plurality of positions in the circumferential direction. The non-engagement faces K 2  are arranged at equal intervals in the circumferential direction. The non-engagement faces K 2  are arranged at intervals of a predetermined angle (90 degree) in the circumferential direction. 
     The reverse-tapered engagement faces K 1  and the non-engagement faces K 2  are alternately arranged in the circumferential direction. 
     As understood from  FIG. 22( a )  to  FIG. 22( d ) , the sectional area of the outer surface  2004  is increased as going to the lower end surface  2008  from the upper end surface  2006 . In the sectional shape of the outer surface  2004 , the reverse-tapered engagement faces K 1  are shifted toward the radially outward direction as going to the lower side. As a result, the reverse-tapered engagement faces K 1  becomes reverse-tapered surfaces (see  FIG. 21 ). 
     The sectional shape of the non-engagement faces K 2  is the same regardless of the axial direction position thereof. The sectional shape of the non-engagement faces K 2  is along a polygon (regular polygon). The sectional shape of the non-engagement faces K 2  is along an octagon (regular octagon). The sectional shape of the non-engagement faces K 2  coincides with respective alternate sides of the regular polygon. The radial direction position of the non-engagement faces K 2  remains the same at any axial direction position. At any axial direction position, the reverse-tapered engagement faces K 1  are located outside of the non-engagement faces K 2  in the radial direction. 
     The sectional shape of the outer surface  2004  has a rotation symmetric property at any axial direction position. At any axial direction position, the sectional shape of the outer surface  2004  has 4-fold rotation symmetry. When the sectional shape of the outer surface  2004  has n-fold rotation symmetry (n is an integer of equal to or greater than 2), n is preferably equal to or greater than 3 and equal to or less than 12, and more preferably equal to or greater than 4 and equal to or less than 8. In the present application, n means the maximum value in values n can take. For example, a square has 4-fold rotation symmetry, and also has 2-fold rotation symmetry. However, n of the square is the maximum value in the values n can take, that is, 4. 
       FIG. 23( a )  to  FIG. 23( d )  shows a hosel hole  2010 .  FIG. 23( a )  is a plan view of the hosel hole  2010 , and shows the upper end surface of the hosel hole  2010 .  FIG. 23( d )  is a bottom view of the hosel hole  2010 , and shows the lower end surface of the hosel hole  2010 .  FIG. 23( b )  and  FIG. 23( c )  are sectional views of the hosel hole  2010 .  FIG. 23( b )  is a sectional view of the hosel hole  2010  at a position corresponding to line B-B in  FIG. 21 .  FIG. 23( c )  is a sectional view of the hosel hole  2010  at a position corresponding to line C-C in  FIG. 21 . 
     The hosel hole  2010  corresponds to the sleeve  2000 . The sleeve  2000  is fixed to a tip end portion of a shaft (not shown in the drawings). The shaft to which the sleeve  2000  is fixed is fixed to the hosel hole  2010  of the head. The hosel hole  2010  is provided on a hosel part  2012  of the head. 
     The hosel hole  2010  has reverse-tapered hole faces J 1 . The reverse-tapered hole faces J 1  are faces corresponding to the respective reverse-tapered engagement faces K 1 . The reverse-tapered hole faces J 1  are arranged at a plurality of positions in the circumferential direction. The reverse-tapered hole faces J 1  are arranged at equal intervals in the circumferential direction. The reverse-tapered hole faces J 1  are arranged at intervals of a predetermined angle (90 degree) in the circumferential direction. 
     The hosel hole  2010  has interference-avoiding faces J 2 . The interference-avoiding faces J 2  are arranged at a plurality of positions in the circumferential direction. The interference-avoiding faces J 2  are arranged at equal intervals in the circumferential direction. The interference-avoiding faces J 2  are arranged at intervals of a predetermined angle (90 degree) in the circumferential direction. 
     The reverse-tapered hole faces J 1  and the interference-avoiding faces J 2  are alternately arranged in the circumferential direction. 
     As understood from  FIG. 23( a )  to  FIG. 23( d ) , the sectional area of the hosel hole  2010  is increased as going to the lower end surface from the upper end surface. In the sectional shape of the hose hole  2010 , the reverse-tapered hole faces J 1  are shifted toward the radially outward direction as going to the lower side. The reverse-tapered hole faces J 1  are reverse-tapered surfaces. 
     The radial direction position and orientation of the interference-avoiding faces J 2  are the same regardless of the axial direction position thereof. The sectional shape of the interference-avoiding faces J 2  is along a polygon (regular polygon). The sectional shape of the interference-avoiding faces J 2  is along an octagon (regular octagon). The sectional shape of the interference-avoiding faces J 2  coincide with respective alternate sides of the regular polygon. The radial direction position of the interference-avoiding faces J 2  remains the same at any axial direction position. At any axial direction position other than lower end surfaces of the interference-avoiding faces J 2 , the interference-avoiding faces J 2  are positioned outside of the reverse-tapered hole faces J 1  in the radial direction. 
     The sectional shape of the hosel hole  2010  has a rotation symmetric property at any axial direction position. At any axial direction position, the sectional shape of the hosel hole  2010  has 4-fold rotation symmetry. When the sectional shape of the hosel hole  2010  has n-fold rotation symmetry (n is an integer of equal to or greater than 2), n is preferably equal to or greater than 3 and equal to or less than 12, and more preferably equal to or greater than 4 and equal to or less than 8. 
       FIG. 24( a )  and  FIG. 24( b )  each show the sleeve  2000  and the hosel hole  2010  in the engagement state.  FIG. 24( a )  is a plan view as viewed from the upper side, and  FIG. 24( b )  is a bottom view as viewed from the lower side.  FIG. 25  is a sectional view taken along line A-A in  FIG. 24( a )  and  FIG. 24( b ) . The golf club according to the present embodiment becomes usable by the engagement state. In the bottom view in  FIG. 24( b ) , the illustration of the sleeve-side connection part  2009  is omitted. 
     In the engagement state, the reverse-tapered engagement faces K 1  abut on the respective reverse-tapered hole faces J 1 . All the reverse-tapered engagement faces K 1  abut on the respective reverse-tapered hole faces J 1 . The reverse-tapered engagement faces K 1  are fitted to the reverse-tapered hole faces J 1 . 
     In the engagement state, the non-engagement faces K 2  are opposed to the respective interference-avoiding faces J 2 . All the non-engagement faces K 2  are opposed to the respective interference-avoiding faces J 2 . A gap (space) is present each between the non-engagement faces K 2  and the respective interference-avoiding faces J 2 . 
       FIG. 26  is a plan view showing the sleeve  2000  and the hosel hole  2010  in a process of passing the sleeve  2000  through the hosel hole  2010 .  FIG. 26  shows a state at a starting time of the passing process.  FIG. 26  shows the upper end surface of the hosel hole  2010  ( FIG. 23( a ) ) and the lower end surface  2008  of the sleeve  2000 . 
     In the present embodiment, a spacer is not used. In the present embodiment, only the sleeve  2000  constitutes the tip engagement part RT. 
     As explained in  FIG. 26 , the tip engagement part RT can be made to pass through the hosel hole  2010 .  FIG. 26  shows the fact that the passing can be performed. The sleeve  2000  has the maximum sectional area at the lower end surface  2008  thereof. On the other hand, the hosel hole  2010  has the minimum sectional area at the upper end thereof.  FIG. 26  shows that the lower end surface  2008  having the maximum sectional area can pass through the upper end of the hosel hole  2010  which has the minimum sectional area. The sleeve  2000  can pass through the hosel hole  2010 . The sleeve  2000  can be inserted to the hosel hole  2010  from the upper side and can come out from the lower side of the hosel hole  2010 . 
     In the present application, a first phase state PH 1  and a second phase state PH 2  are defined. The first phase state PH 1  and the second phase state PH 2  show relative phase relationships between the hosel hole  2010  and the sleeve  2000 . A mutual shifting between the first phase state PH 1  and the second phase state PH 2  can be performed by rotating the sleeve  2000  with respect to the hosel hole  2010 . 
     In the first phase state PH 1 , the reverse-tapered engagement faces K 1  are opposed to the respective interference-avoiding faces J 2 .  FIG. 26  shows the first phase state PH 1 . As described above, in the first phase state PH 1  ( FIG. 26 ), the hosel hole  2010  allows the tip engagement part RT (sleeve  2000 ) to pass through the hosel hole  2010 . Although not clearly shown in  FIG. 26 , a (slight) clearance is present each between the reverse-tapered engagement faces K 1  and the respective interference-avoiding faces J 2 . 
     In the first phase state PH 1 , the non-engagement faces K 2  are opposed to the respective reverse-tapered hole faces J 1 . In the first phase state PH 1 , a gap is present each between the non-engagement faces K 2  and the reverse-tapered hole faces J 1 . 
     In the second phase state PH 2 , the reverse-tapered engagement faces K 1  are opposed to the respective reverse-tapered hole faces J 1 .  FIG. 24( a )  and  FIG. 24( b )  show the second phase state PH 2 . In the second phase state PH 2 , the engagement state is achieved. As described above, in the engagement state, the reverse-tapered engagement faces K 1  are brought into surface-contact with the respective reverse-tapered hole faces J 1 . In the second phase state PH 2 , the reverse-tapered engagement faces K 1  can be fitted to the respective reverse-tapered hole faces J 1 . 
     Thus, in assembling the golf club according to the present embodiment, the sleeve  2000  is fixed (bonded) to the tip end portion of a shaft. Next, the sleeve  2000  is inserted to the hosel hole  2010  from above, and is made to completely pass through the hosel hole  2010 . By the passing, the sleeve  2000  reaches the lower side of the sole, and the shaft is inserted to the hosel hole  2010 . In the passing process, the first phase state PH 1  is adopted (see  FIG. 26 ). Next, the sleeve  2000  fixed to the shaft is rotated so that the first phase state PH 1  is shifted to the second phase state PH 2 . The sleeve  2000  is exposed to the outside, and thus can be freely rotated. In the present embodiment, the angle of the rotation is 45 degrees. Finally, the shaft to which the sleeve  2000  is fixed is pulled up, and the reverse-tapered engagement faces K 1  are fitted to the respective reverse-tapered hole faces J 1 . This final state is shown in  FIG. 24( a ) ,  FIG. 24( b )  and  FIG. 25 . 
     Thus, the first phase state PH 1  enables the sleeve  2000  to pass through the hosel hole  2010 . The second phase state PH 2  enables the sleeve  2000  to be fitted to the hosel hole  2010 . 
     In the sleeve  2000 , a center line of the sleeve inner surface  2002  is not inclined with respect to a center line of the sleeve outer surface. Of course, the center line of the sleeve inner surface  2002  may be inclined with respect to the center line of the sleeve outer surface. The center line of the sleeve inner surface  2002  may be parallel and eccentric with respect to the center line of the sleeve outer surface. 
     In the present embodiment, a spacer is not used. However, a spacer can be provided. For example, the shape of the sleeve  2000  can be formed by a spacer and a sleeve. In this case, the outer shape of the sleeve may be a regular eight-sided pyramid having a reverse-tapered shape. The spacer suited to the sleeve may have an inner shape of a regular eight-sided pyramid corresponding to the outer shape of the sleeve, and may have an outer shape which is the same as the shape of the sleeve  2000 . When a spacer is used, an inclination angle can be set between the center line of the inner shape of the sleeve and the center line of the outer shape of the sleeve, and an inclination angle can be set between the center line of the inner shape of the spacer and the center line of the outer shape of the spacer. In this case, as described above, an independent variability of the loft angle and an independent variability of the lie angle can be attained. 
     A taper ratio of the reverse-tapered fitting is not limited. When the taper ratio is excessively small, it may be difficult to release the reverse-tapered fitting. Meanwhile, when the taper ratio is excessively large, the size of the fitting portion becomes large. An excessively large fitting portion deteriorates the degree of freedom of design of the golf club. In this respect, the taper ratio is preferably set within a predetermined range. 
     In the above-explained respects, the outer surface of the sleeve has a taper ratio of preferably equal to or greater than 0.2/30, more preferably equal to or greater than 0.5/30, and still more preferably equal to or greater than 1.0/30. In the above-explained respects, the taper ratio of the outer surface of the sleeve is preferably equal to or less than 5/30, more preferably equal to or less than 4/30, and still more preferably equal to or less than 3.5/30. 
     In the above-explained respects, the inner surface of the spacer has a taper ratio of preferably equal to or greater than 0.2/30, more preferably equal to or greater than 0.5/30, and still more preferably equal to or greater than 1.0/30. In the above-explained respects, the taper ratio of the inner surface of the spacer is preferably equal to or less than 5/30, more preferably equal to or less than 4/30, and still more preferably equal to or less than 3.5/30. 
     In the above-explained respects, the outer surface of the spacer has a taper ratio of preferably equal to or greater than 0.2/30, more preferably equal to or greater than 0.5/30, and still more preferably equal to or greater than 1.0/30. In the above-explained respects, the taper ratio of the outer surface of the spacer is preferably equal to or less than 10/30, more preferably equal to or less than 7/30, and still more preferably equal to or less than 5/30. 
     In the above-explained respects, the reverse-tapered hole has a taper ratio of preferably equal to or greater than 0.2/30, more preferably equal to or greater than 0.5/30, and still more preferably equal to or greater than 1.0/30. In the above-explained respects, the taper ratio of the reverse-tapered hole is preferably equal to or less than 10/30, more preferably equal to or less than 7/30, and still more preferably equal to or less than 5/30. 
     In the above-explained respects, the reverse-tapered engagement faces have a taper ratio of preferably equal to or greater than 0.2/30, more preferably equal to or greater than 0.5/30, and still more preferably equal to or greater than 1.0/30. In the above-explained respects, the taper ratio of the reverse-tapered engagement faces is preferably equal to or less than 10/30, more preferably equal to or less than 7/30, and still more preferably equal to or less than 5/30. 
     In the above-explained respects, the reverse-tapered hole faces have a taper ratio of preferably equal to or greater than 0.2/30, more preferably equal to or greater than 0.5/30, and still more preferably equal to or greater than 1.0/30. In the above-explained respects, the taper ratio of the reverse-tapered hole faces is preferably equal to or less than 10/30, more preferably equal to or less than 7/30, and still more preferably equal to or less than 5/30. 
     The definition of the taper ratio is as follows. When a length in an axial direction of the tapered surface is represented by Da, and a varied width in a direction perpendicular to the axial direction is represented by Db, then the taper ratio is Db/Da. In the taper ratio, varied amount in both sides, not an inclination (gradient) in one side, is considered. For example, in a case of a circular cone, the varied width Db is a varied amount of a diameter thereof, not a radius thereof. For example, in a case of a regular quadrangular pyramid, although the sectional shape of the regular quadrangular pyramid is a square, the varied width Db is a varied amount of the length of one side of the square. 
     The sectional area of the reverse-tapered hole is gradually increased toward the lower side (sole side). The sectional shape of the reverse-tapered hole is a non-circle. The sectional shape of the non-circle prevents relative rotation between the hosel hole and the tip engagement part. The non-circle includes all shapes other than a circle. For example, the non-circle may be a shape having a projection, a recess, or a flat portion at at least a part in the circumferential direction of a circle. The sectional shape of the reverse-tapered hole may be a polygon. Examples of the polygon include a triangle, a tetragon, a pentagon, a hexagon, a heptagon, an octagon, and a dodecagon. The polygon may be an N-sided polygon in which N is an even number, and examples of the N-sided polygon include the tetragon, the hexagon, the octagon, and the dodecagon. In light of anti-rotation, the tetragon, the hexagon and the octagon are preferable. The sectional shape of the reverse-tapered hole may be a regular polygon. Preferable examples of the regular polygon include a regular triangle, a regular tetragon (square), a regular pentagon, a regular hexagon, a regular heptagon, a regular octagon, and a regular dodecagon. The regular polygon is more preferably a regular N-sided polygon in which N is an even number, and examples of the regular N-sided polygon include the regular tetragon (square), the regular hexagon, the regular octagon, and the regular dodecagon. In light of anti-rotation, the regular tetragon, the regular hexagon, and the regular octagon are more preferable. 
     The reverse-tapered hole preferably includes a plurality of faces. Each of the faces may be a plane face, or may be a curved face. From the viewpoint of ensuring surface-contact with the tip engagement part, each of these faces is preferably a plane face. From the viewpoint of ensuring surface-contact with the tip engagement part, the reverse-tapered hole may be a pyramid surface. The pyramid surface means a part of the outer surface of a pyramid. Examples of the pyramid surface include a three-sided pyramid surface, a four-sided pyramid surface, a five-sided pyramid surface, a six-sided pyramid surface, a seven-sided pyramid surface, an eight-sided pyramid surface, and a twelve-sided pyramid surface. The pyramid surface is more preferably an N-sided pyramid surface in which N is an even number, and examples of the N-sided pyramid surface include the four-sided pyramid surface, the six-sided pyramid surface, the eight-sided pyramid surface, and the twelve-sided pyramid surface. In light of anti-rotation, the four-sided pyramid surface, the six-sided pyramid surface and the eight-sided pyramid surface are more preferable. 
     When the reverse-tapered hole faces J 1  are adopted as in the embodiment of  FIG. 21  to  FIG. 26 , each of the reverse-tapered hole faces J 1  may be a plane face, or may be a curved face. From the viewpoint of ensuring surface-contact with the reverse-tapered engagement faces K 1 , each of the reverse-tapered hole faces J 1  is preferably a plane face. From the viewpoint of ensuring surface-contact with the reverse-tapered engagement faces K 1 , the reverse-tapered hole faces J 1  may constitute a pyramid surface. The pyramid surface means a part of the outer surface of a pyramid. Examples of the pyramid surface include a three-sided pyramid surface, a four-sided pyramid surface, a five-sided pyramid surface, a six-sided pyramid surface, a seven-sided pyramid surface, an eight-sided pyramid surface, and a twelve-sided pyramid surface. The pyramid surface is more preferably an N-sided pyramid surface in which N is an even number, and examples of the N-sided pyramid surface include the four-sided pyramid surface, the six-sided pyramid surface, the eight-sided pyramid surface, and the twelve-sided pyramid surface. In light of anti-rotation, the four-sided pyramid surface, the six-sided pyramid surface, and the eight-sided pyramid surface are more preferable. 
     The area of a figure formed by a sectional line of the outer surface of the sleeve is gradually increased toward the lower side (sole side). The sectional shape of the outer surface of the sleeve is a non-circle. The sectional shape of the non-circle prevents relative rotation between the sleeve and an abutting portion. The abutting portion is the inner surface of the spacer or the reverse-tapered hole. When a plurality of spacers are present, the abutting portion is the inner surface of the innermost spacer. The non-circle includes all shapes other than a circle. For example, the non-circle may be a shape having a projection, a recess, or a flat portion at at least a part in the circumferential direction of a circle. The sectional shape of the outer surface of the sleeve may be a polygon. Examples of the polygon include a triangle, a tetragon, a pentagon, a hexagon, a heptagon, an octagon, and a dodecagon. The polygon is preferably an N-sided polygon in which N is an even number, and examples of the N-sided polygon include the tetragon, the hexagon, the octagon, and the dodecagon. In light of anti-rotation, the tetragon, the hexagon, and the octagon are preferable. The sectional shape of the outer surface of the sleeve may be a regular polygon. Preferable examples of the regular polygon include a regular triangle, a regular tetragon (square), a regular pentagon, a regular hexagon, a regular heptagon, a regular octagon, and a regular dodecagon. The regular polygon is more preferably a regular N-sided polygon in which N is an even number, and examples of the regular N-sided polygon include the regular tetragon (square), the regular hexagon, the regular octagon, and the regular dodecagon. In light of anti-rotation, the regular tetragon, the regular hexagon, and the regular octagon are more preferable. 
     The outer surface of the sleeve preferably includes a plurality of faces. Each of the faces may be a plane face, or may be a curved face. From the viewpoint of ensuring surface-contact with the abutting portion, each of these faces is preferably a plane face. From the viewpoint of ensuring surface-contact with the abutting portion, the outer surface of the sleeve is preferably a pyramid surface. Examples of the pyramid surface include a three-sided pyramid surface, a four-sided pyramid surface, a five-sided pyramid surface, a six-sided pyramid surface, a seven-sided pyramid surface, an eight-sided pyramid surface, and a twelve-sided pyramid surface. The pyramid surface is more preferably an N-sided pyramid surface in which N is an even number, and examples of the N-sided pyramid surface include the four-sided pyramid surface, the six-sided pyramid surface, the eight-sided pyramid surface, and the twelve-sided pyramid surface. In light of anti-rotation, the four-sided pyramid surface, the six-sided pyramid surface and the eight-sided pyramid surface are more preferable. 
     As described above, the golf club may have one or more spacers. The inner surface of the spacer has the same shape as the shape of an outer surface of a member (inner member) fitted inside the spacer. The inner member is the sleeve or another spacer. 
     The area of a figure formed by a sectional line of the inner surface of the spacer is gradually increased toward the lower side (sole side). The sectional shape of the inner surface of the spacer is a non-circle. The sectional shape of the non-circle prevents relative rotation between the spacer and the inner member. When a plurality of spacers are present, the inner member is another spacer. The non-circle includes all shapes other than a circle. For example, the non-circle may be a shape having a projection, a recess, or a flat portion at at least a part in the circumferential direction of a circle. The sectional shape of the inner surface of the spacer may be a polygon. Examples of the polygon include a triangle, a tetragon, a pentagon, a hexagon, a heptagon, an octagon, and a dodecagon. The polygon is preferably an N-sided polygon in which N is an even number, and examples of the N-sided polygon include the tetragon, the hexagon, the octagon, and the dodecagon. In light of anti-rotation, the tetragon, the hexagon, and the octagon are preferable. The sectional shape of the inner surface of the spacer may be a regular polygon. Preferable examples of the regular polygon include a regular triangle, a regular tetragon (square), a regular pentagon, a regular hexagon, a regular heptagon, a regular octagon, and a regular dodecagon. The regular polygon is more preferably a regular N-sided polygon in which N is an even number, and examples of the regular N-sided polygon include the regular tetragon (square), the regular hexagon, the regular octagon, and the regular dodecagon. In light of anti-rotation, the regular tetragon, the regular hexagon, and the regular octagon are more preferable. 
     The inner surface of the spacer preferably includes a plurality of faces. Each of the faces may be a plane face, or may be a curved face. From the viewpoint of ensuring surface-contact with the inner member, each of these faces is preferably a plane face. From the viewpoint of ensuring surface-contact with the inner member, the inner surface of the spacer may be a pyramid surface. Examples of the pyramid surface include a three-sided pyramid surface, a four-sided pyramid surface, a five-sided pyramid surface, a six-sided pyramid surface, a seven-sided pyramid surface, an eight-sided pyramid surface, and a twelve-sided pyramid surface. The pyramid surface is more preferably an N-sided pyramid surface in which N is an even number, and examples of the N-sided pyramid surface include the four-sided pyramid surface, the six-sided pyramid surface, the eight-sided pyramid surface, and the twelve-sided pyramid surface. In light of anti-rotation, the four-sided pyramid surface, the six-sided pyramid surface and the eight-sided pyramid surface are more preferable. 
     As described above, the club of the present disclosure includes a tip engagement part. The tip engagement part may be constituted with only the sleeve, or may by constituted with the sleeve and one or more spacers. When the spacer is not used, the outer surface of the tip engagement part is the outer surface of the sleeve. When one spacer is used, the outer surface of the tip engagement part is the outer surface of the spacer. When two or more spacers are used, the outer surface of the tip engagement part is the outer surface of the outermost spacer. 
     The area of a figure formed by a sectional line of the outer surface of the tip engagement part is gradually increased toward the lower side (sole side). The sectional shape of the outer surface of the tip engagement part is a non-circle. The sectional shape of the non-circle prevents relative rotation between the tip engagement part and the reverse-tapered hole. The non-circle includes all shapes other than a circle. For example, the non-circle may be a shape having a projection, a recess, or a flat portion at at least a part in the circumferential direction of a circle. The sectional shape of the outer surface of the tip engagement part may be a polygon. Examples of the polygon include a triangle, a tetragon, a pentagon, a hexagon, a heptagon, an octagon, and a dodecagon. The polygon is preferably an N-sided polygon in which N is an even number, and examples of the N-sided polygon include the tetragon, the hexagon, the octagon, and the dodecagon. In light of anti-rotation, the tetragon, the hexagon, and the octagon are preferable. The sectional shape of the outer surface of the tip engagement part may be a regular polygon. Preferable examples of the regular polygon include a regular triangle, a regular tetragon (square), a regular pentagon, a regular hexagon, a regular heptagon, a regular octagon, and a regular dodecagon. The regular polygon is more preferably a regular N-sided polygon in which N is an even number, and examples of the regular N-sided polygon include the regular tetragon (square), the regular hexagon, the regular octagon, and the regular dodecagon. In light of anti-rotation, the regular tetragon, the regular hexagon, and the regular octagon are more preferable. 
     The outer surface of the tip engagement part preferably includes a plurality of faces. Each of the faces may be a plane face, or may be a curved face. From the viewpoint of ensuring surface-contact with the reverse-tapered hole, each of these faces is preferably a plane face. From the viewpoint of ensuring surface-contact with the reverse-tapered hole, the outer surface of the tip engagement part may be a pyramid surface. Examples of the pyramid surface include a three-sided pyramid surface, a four-sided pyramid surface, a five-sided pyramid surface, a six-sided pyramid surface, a seven-sided pyramid surface, an eight-sided pyramid surface, and a twelve-sided pyramid surface. The pyramid surface is more preferably an N-sided pyramid surface in which N is an even number, and examples of the N-sided pyramid surface include the four-sided pyramid surface, the six-sided pyramid surface, the eight-sided pyramid surface, and the twelve-sided pyramid surface. In light of anti-rotation, the four-sided pyramid surface, the six-sided pyramid surface and the eight-sided pyramid surface are more preferable. 
     When the tip engagement part RT is the sleeve  2000  ( FIG. 21 ), the outer surface of the reverse-tapered engagement faces K 1  preferably includes a plurality of faces. Each of the faces may be a plane face, or may be a curved face. From the viewpoint of ensuring surface-contact with the reverse-tapered hole faces J 1 , each of these faces is preferably a plane face. From the viewpoint of ensuring surface-contact with the reverse-tapered hole faces J 1 , the outer surface of the reverse-tapered engagement faces K 1  preferably constitutes a pyramid surface. Examples of the pyramid surface include a three-sided pyramid surface, a four-sided pyramid surface, a five-sided pyramid surface, a six-sided pyramid surface, a seven-sided pyramid surface, an eight-sided pyramid surface, and a twelve-sided pyramid surface. The pyramid surface is more preferably an N-sided pyramid surface in which N is an even number, and examples of the N-sided pyramid surface include the four-sided pyramid surface, the six-sided pyramid surface, the eight-sided pyramid surface, and the twelve-sided pyramid surface. In light of anti-rotation, the four-sided pyramid surface, the six-sided pyramid surface and the eight-sided pyramid surface are more preferable. 
     Each of the above-mentioned numbers N is preferably an integer of equal to or greater than 3. 
     Thus, the reverse-tapered fitting is formed by the sleeve and the reverse-tapered hole while the spacer is interposed as necessary. 
       FIG. 27  shows a golf club  3100  which is another embodiment.  FIG. 27  shows only the vicinity of a head of the golf club  3100 .  FIG. 28  is an exploded perspective view of the golf club  3100 . 
     The golf club  3100  has a head  3200 , a shaft  3300 , a sleeve  3400 , a spacer  3500 , and a grip (not shown in the drawings). The sleeve  3400  and the spacer  3500  constitute a tip engagement part RT. 
     The head  3200  has a hosel part  3202 . The hosel part  3202  has a hosel hole  3204 . The hosel hole  3204  has a reverse-tapered hole  3206 . The shape of the reverse-tapered hole  3206  corresponds to the shape of the outer surface of the tip engagement part RT. In other words, the shape of the reverse-tapered hole  3206  corresponds to the shape of the outer surface of the spacer  3500 . 
     The hosel part  3202  has a hosel slit  3206 . The hosel slit  3206  is provided lateral to the hosel part  3202 . The hosel slit  3206  is an opening formed between the inside of the hosel hole  3204  and the outside of the head. The hosel slit  3206  is opened to the axial-direction upper side, and is also opened to the axial-direction lower side. The hosel slit  3206  is provided on a heel side of the hosel part  3202 . Because of the hosel slit  3206 , a part of the reverse-tapered hole  3206  is lacking. 
     The head  3200  has a female screw part  3220 . The female screw part  3220  is provided on the lower side of the hosel part  3202 . The female screw part  3220  is provided on the lower side of the hosel hole  3204 . 
     Because of the presence of the slit  3206 , a part in the circumferential direction of the female screw part  3220  is lacking. However, the lack does not affect the screw-connection to the screw member  600 . The female screw part  3220  can be screw-connected to the male screw part  604  of the screw member  600 . The screw member  600  can be connected to the sleeve  3400  (sleeve-side connection part  3410 ). 
       FIG. 28  shows a width Ws of the hosel slit  3206 . The width Ws is larger than the diameter of the shaft  3300 . The width Ws is larger than at least the diameter of the thinnest portion of the shaft  3300 . Therefore, the hosel slit  3206  allows the shaft  3300  to pass therethrough. The hosel slit  3206  allows the shaft  3300  moving in the axial perpendicular direction to pass therethrough. 
     Because of the hosel slit  3206 , a part in the circumferential direction of the hosel hole  3204  is lacking. From the viewpoint of enhancing the retention for the tip engagement part RT, the width Ws is preferably small. For example, the width Ws may be larger than the diameter of the thinnest portion of an exposed part of the shaft  3300 . The exposed part means a part to which a sleeve and a grip are not attached, and is exposed to the outside. Needless to say, the width Ws is set so as not to allow passage of the tip engagement part RT. The tip engagement part RT cannot pass through the hosel slit  3206 . 
     The sleeve  3400  is the same as the above-described sleeve  400 . The sleeve  3400  has a sleeve-side connection part  3410 . The sleeve-side connection part  3410  is the same as the above-described sleeve-side connection part  410 . The sleeve  3400  is fixed to a tip end portion of the shaft  3300 . An adhesive is used for the fixation. 
     The shape of the spacer  3500  is the same as that of the above-described spacer  500 . However, the spacer  3500  does not have a divided structure. The spacer  3500  is an integral body as a whole. 
       FIG. 29  shows a procedure of mounting the shaft  3300  of the golf club  3100  to the head  3200 . 
     In the mounting procedure, a shaft assembly  3700  is prepared first (step (a) in  FIG. 29 ). The shaft assembly  3700  has a shaft  3300 , a sleeve  3400 , and a spacer  3500 . After the shaft  3300  has been inserted to the spacer  3500 , the sleeve  3400  is fixed to the tip end portion of the shaft  3300 , whereby the shaft assembly  3700  is obtained. In the shaft assembly  3700 , the sleeve  3400  is fixed to the shaft  3300 , but the spacer  3500  is not fixed to the shaft  3300 . In a state in which the shaft  3300  is inserted, the spacer  3500  can be moved in the axial direction (see step (a) in  FIG. 29 ). However, because of the presence of the sleeve  3400 , the spacer  3500  will not fall off from the shaft  3300 . 
     Next, in the shaft assembly  3700 , the spacer  3500  is moved until it abuts on the outer surface of the sleeve  3400  (step (b) in  FIG. 29 ). That is, the spacer  3500  is moved to the most distal side of the shaft assembly  3700 . This movement causes the spacer  3500  to be engaged with the sleeve  3400 , whereby the tip engagement part RT is formed. 
     Next, the shaft  3300  is made to pass through the hosel slit  3206 , whereby the shaft  3300  is moved to the inside of the reverse-tapered hole  3206  (step (c) in  FIG. 29 ). As a result of the movement of the shaft  3300 , the tip engagement part RT is moved to the sole side of the head  3200 . 
     Next, the shaft  3300  (shaft assembly  3700 ) is moved to the grip side along the axial direction, whereby the tip engagement part RT is fitted to the reverse-tapered hole  3206  (step (d) of  FIG. 29 ). 
     Finally, the screw member  600  is screwed to the female screw part  3220 . The male screw part  604  of the screw member  600  is screw-connected to the female screw part  3220 . By the screw-connection, the screw member  600  presses the tip engagement part RT to the upper side, whereby the engagement state is ensured. In addition, the screw member  600  is automatically connected to the sleeve  3400 . 
     In the present embodiment, the hosel slit  3206  is provided, and the shaft  3300  can pass through the hosel slit  3206 . Therefore, the sleeve  3400  may not be allowed to pass through the hosel hole  3204 . The spacer  3500  may not have a divided structure. 
       FIG. 30  is a sectional view of the screw member  600 .  FIG. 31  is a sectional view showing a state in which the screw member  600  is connected to the sleeve  400 . In these sectional views, a center line CL of the screw member  600  is indicated by a one-dot chain line, and the illustration of portions on the lower side of the center line CL is omitted. The actual sectional views are line-symmetric about the center line CL as an axis of symmetry. 
     As described above, the screw member  600  has the screw-side connection part  602 , the male screw part  604 , and the rotating engagement part  606 . A detailed structure of the screw member  600  will be explained below. 
     The screw member  600  has a screw body  610 . A male screw part  604  is formed on an outer circumferential surface of the screw body  610 . The rotating engagement part  606  is provided on a bottom surface  612  of the screw body  610 . The rotating engagement part  606  is a recess having a non-circular sectional shape. By inserting a wrench to the rotating engagement part  606 , the screw body  610  can be rotated about the center line CL. The wrench preferably has a torque limiter. With the torque limiter, the force with which the screw member  600  presses the tip engagement part RT can be adjusted. From the viewpoint of the Golf Rules, the wrench is preferably used exclusively for the screw member  600 . 
     The screw-side connection part  602  has a first member  620 , a second member  622 , and a third member  624 . The first member  620 , the second member  622 , and the third member  624  each have a cylindrical shape as a whole. The first member  620  is exposed to the outside. The second member  622  is positioned inside the first member  620 . The second member  622  is fixed to the screw body  610 . The second member  622  may be integral with the screw body  610 . The second member  622  rotates with the rotation of the screw body  610 . The third member  624  is positioned inside the second member  622 . The first member  620  can be slidably moved with respect to the second member  622 . The third member  624  can be slidably moved with respect to the second member  622 . 
     The screw-side connection part  602  has a first elastic body  630  and a second elastic body  632 . The first elastic body  630  is a coil spring. The first elastic body  630  is a compression spring. The second elastic body  632  is a coil spring. The second elastic body  632  is a compression spring. 
     The screw-side connection part  602  has a ball  634 . The ball  634  is a steel ball. In the present application, the ball  634  is also referred to as an engagement ball. 
     The second member  622  has a ball housing hole  636 . The ball housing hole  636  is a through hole. The engagement ball  634  is disposed in the ball housing hole  636 . The diameter of the ball housing hole  636  is substantially equal to the diameter of the ball  634 . The engagement ball  634  can pass through the ball housing hole  636 . 
     The diameter of the ball  634  is larger than the depth of the ball housing hole  636 . For this reason, the ball  634  housed in the ball housing hole  636  is in a state of being projected inside or outside the second member  622 . In  FIG. 30 , the ball  634  is projected outside the second member  622 . 
     Although not shown in the drawings, the ball housing holes  636  are provided at a plurality of positions in the circumferential direction. The ball housing holes  636  are uniformly arranged in the circumferential direction. In the present embodiment, four ball housing holes  636  are arranged at 90° intervals. One ball  634  is disposed in each of the ball housing holes  636 . Here, the circumferential direction means the circumferential direction of the screw member  600 . 
     The second member  622  has a stopper  638 . The stopper  638  is an annular member disposed in a circumferential groove provided on the outer circumferential surface of the second member  622 . A circlip is used as the annular member. 
     The first elastic body  630  is disposed between (a step surface of) the first member  620  and (a step surface of) the second member  622 . The first elastic body  630  biases the first member  620  to a sleeve side (the right side in  FIG. 30 ) with respect to the second member  622 . 
     The second elastic body  632  is disposed between (a step surface of) the screw body  610  and (a bottom surface of) of the third member  624 . The second elastic body  632  biases the third member  624  to the sleeve side (the right side in  FIG. 30 ) with respect to the screw body  610 . 
     In the following, the state of the screw member  600  shown in  FIG. 30  is also referred to as a non-connected state, and the state of the screw member  600  shown in  FIG. 31  is also referred to as a connected state. The sleeve side is also referred to as an upper side, and the sole side is also referred to as a lower side. The right side in  FIG. 30  and  FIG. 31  is the upper side, and the left side in  FIG. 30  and  FIG. 31  is the lower side. 
     In the non-connected state ( FIG. 30 ), the third member  624  is pressed to the upper side by the second elastic body  632 , and is located at a position P 1  on a relatively front side. In the position P 1 , the third member  624  abuts on the step surface of the second member  622 . 
     The third member  624  located at the position P 1  has a portion positioned inside the ball housing hole  636 . The third member  624  located at the position P 1  prevents the ball  634  from being projected inside. Therefore, in the non-connected state, the ball  634  is projected outside the second member  622 . 
     In the non-connected state ( FIG. 30 ), the first member  620  is pressed to the upper side by the first elastic body  630 , but its movement to the upper side is regulated by the ball  634  being projected outside. As a result, in the non-connected state, the first member  620  is located at a position Px on a relatively lower side. 
     The first member  620  has an inclined surface  640 . The inclined surface  640  is a conical concave surface. The inclined surface  640  is inclined so as to extend toward the radially outward direction as going to the upper side. The radial direction means the radial direction of the screw member  600 . In the non-connected state, the inclined surface  640  abuts on the ball  634 . 
     When the male screw part  604  of the screw body  610  is screwed into the female screw part  220  (see  FIG. 5 ) of the head by rotating the screw member  600  (screw body  610 ) in the first direction, the screw body  610  is moved to the upper side, and the second member  622  is also positioned on the upper side by being pressed by the screw body  610 . As a result, the entire screw member  600  is moved to the upper side. 
     When the movement of the screw member  600  to the upper side progresses as the rotation of the crew member  600  in the first direction is continued, the sleeve-side connection part  410  of the sleeve  400  is inserted inside the screw member  600 . More specifically, the sleeve-side connection part  410  is inserted inside the second member  622 . In the insertion, (a lower end surface of) the sleeve-side connection part  410  presses the third member  624  to the lower side against the biasing force of the second elastic body  632 . By the insertion of the sleeve-side connection part  410 , the third member  624  is moved to a position P 2  on a relatively lower side. 
     By this movement, the abutment between the third member  624  and the ball  634  is released. In place of the third member  624 , the engagement recess  412  of the sleeve-side connection part  410  reaches the same axial direction position as that of the ball  634 . 
     As described above, the ball  634  receives a pressing force from the inclined surface  640  by the biasing force of the first elastic body  630 , and the pressing force includes a component force to the inner side in the radial direction. Accordingly, the ball  634  falls in the engagement recess  412  that has been moved to the inner side in the radial direction of the ball  634  ( FIG. 31 ). A part of the ball  634  is located within the engagement recess  412 , and the other parts thereof are located within the ball housing hole  636 . Therefore, the ball  634  locks the sleeve-side connection part  410  to the screw-side connection part  602 . 
     When the ball  634  falls in the engagement recess  412 , the abutment between the ball  634  and the first member  620  is released. As a result, the first member  620  is moved to a second position Py on a relatively upper side by the biasing force of the first elastic body  630 . At the second position Py, the first member  620  abuts on the stopper  638 . The connected state is achieved by the movement of the first member  620 . 
     As shown in  FIG. 31 , the first member  620  located at the second position Py prevents the ball  634  from being projected outside. Therefore, the state in which the ball  634  falls in the engagement recess  412  is maintained. That is, the connected state is maintained. As long as the second position Py of the first member  620  is maintained, it is not possible to pull out the sleeve-side connection part  410  from the screw member  600 . 
     Thus, by simply rotating the screw member  600  in the first direction with respect to the female screw part  220 , the sleeve  400  and the screw member  600  are automatically connected to each other, whereby the connected state is achieved ( FIG. 31 ). In the connected state, the third member  624  is located at the position P 2 , the first member  620  is located at the position Py, and the ball  634  is engaged with the engagement recess  412 . 
     In the connected state, the screw member  600  presses the sleeve  400  to the upper side. Specifically, an upper end surface  642  of the second member  622  presses the sleeve  400 . As a result, the screw member  600  presses the sleeve  400  in the engaging direction. Therefore, the tip engagement part RT including the sleeve  400  is reliably fitted to the hosel hole  204 , whereby backlash resulting from the dimensional error can be eliminated. 
     Elimination of backlash is accompanied by the elastic deformation of the tip engagement part RT or the hosel hole  204 . Once fitting accompanied by the elastic deformation has been achieved, it will be difficult to release the fitting. That is, the tip engagement part RT is fitted into the hosel hole  204 , and thus is difficult to be pulled out from the hosel hole  204 . The connection between the screw member  600  and the sleeve  400  can solve this problem. When the screw member  600  is rotated in the second direction while maintaining the connected state, the screw member  600  is moved to the lower side, and the sleeve  400  is pulled in the engagement releasing direction by the screw member  600 . As a result, the tip engagement part RT including the sleeve  400  is pulled out from the hosel hole  204 . 
     As described above, the connection is maintained unless the first member  620  located at the second position Py is moved. Therefore, the connection is maintained when the screw member  600  is simply rotated in the second direction. The pulling-out of the tip engagement part RT is achieved by simply rotating the screw member  600  in the second direction. 
     To release the connection, the first member  620  may be moved to the lower side. The connected state can be released by moving the first member  620  to the position Px so as to bring about a state in which the ball  634  can be projected outside. The movement of the first member  620  is achieved by an external force. For example, the connected state can be released by simply moving the first member  620  to the lower side by fingers. The first member  620  can be moved by applying an external force greater than the biasing force of the first elastic body  630 . 
     Thus, the connection can be easily released. The connection may be released upon confirmation of pulling out of the tip engagement part RT including the sleeve  400  from the hosel hole  204 . 
     As explained above, in the present embodiment, by the rotation in the first direction DR 1 , the screw member  600  presses the tip engagement part RT in the engaging direction, and the sleeve-side connection part  410  is inserted to the screw-side connection part  602 . The connection between the sleeve-side connection part  410  and the screw-side connection part  602  is automatically completed by the sleeve-side connection part being inserted to the screw-side connection part. Therefore, by simply screwing the screw member  600 , the backlash between the tip engagement part RT and the head is eliminated, and the above-described connection that is effective for pulling out the tip engagement part RT is completed simultaneously. 
     In the present embodiment, the screw member  600  includes the screw body  610  having the male screw part  604 ; the first member  620  constituting an outer circumferential surface of the screw-side connection part  602 ; the second member  622  positioned inside the first member  620 ; and the third member  624  positioned inside the second member  622 . The screw member  600  further includes the first elastic body  630  that is disposed between the first member  620  and the second member  622 , and biases the first member  620  to the sleeve side (upper side) with respect to the second member  622 ; the second elastic body  632  that biases the third member  624  to the sleeve side (upper side); and the engagement ball  634  disposed in the ball housing hole  636 . The sleeve-side connection part  410  has the engagement recess  412 . In a non-connected state, the ball  634  is projected outside the second member  622  by the third member  624  being positioned inside the ball  634 , and by the projected ball  634 , the first member  620  is located at a first position Px at which movement thereof to the sleeve side is regulated. In a connected state in which the connection has been achieved, the third member  624  is moved to a position at which the third member  624  is removed from inside of the engagement ball  634  by the sleeve-side connection part  410 , the engagement ball  634  falls in the engagement recess  412 , and the movement regulation on the first member  620  by the engagement ball  634  is released, whereby the first member  620  is moved to a second position Py at which the first member  620  prevents the engagement ball  634  from projecting to the outside. Therefore, the above-described automatic connection is reliably achieved, and the connection can be easily released. 
     A mechanism used for a fluid coupling or an instant coupling may be adopted as the connecting structure of the screw-side connection part and the sleeve-side connection part. This mechanism is disclosed in Japanese Unexamined Utility Model Application Publication No. 60-108888, for example. Such a mechanism achieves connection by simply inserting one member into the other member, and the connection can be easily released, and therefore can be applied to the golf club according to the present disclosure. 
       FIG. 32  and  FIG. 33  are sectional views showing a screw member  650  according to another embodiment, and a sleeve  450  corresponding to the screw member  650 .  FIG. 32  shows a non-connected state, and  FIG. 33  shows a connected state. 
     In  FIG. 32  and  FIG. 33 , a center line CL of the screw member  650  is indicated by a one-dot chain line, and the illustration of portions on the lower side of the center line CL is omitted. The actual sectional views are line-symmetric about the center line CL as an axis of symmetry. 
     The screw member  650  has a cylindrical shape as a whole. The screw member  650  includes a screw-side connection part  652  and a male screw part  654 . The screw member  650  further includes a rotating engagement part  656 . The rotating engagement part  656  is a hole coaxial with the center line CL. The sectional shape of the hole is a non-circle. The rotating engagement part  656  penetrates the screw member  650 . 
     The screw member  650  includes a screw body part  660  and an elastic deformation part  662 . The elastic deformation part  662  has an engagement projection  664 . The screw body part  660  has a cylindrical shape. The male screw part  654  is formed on the outer circumferential surface of the screw body part  660 . The elastic deformation part  662  is positioned on the upper side of the screw body part  660 . 
     The elastic deformation part  662  exhibits a shape resembling a bent bar as a whole. The elastic deformation part  662  extends from an upper end surface  666  of the screw body part  660  toward the upper side. The upper end (right end in  FIG. 32 ) of the elastic deformation part  662  is a free end, and the engagement projection  664  is formed at the free end. 
     Although not shown in the drawings, the elastic deformation parts  662  are provided at a plurality of locations in the circumferential direction of the screw body part  660 . In the present embodiment, the elastic deformation parts  662  are provided at four locations in the circumferential direction of the screw body part  660 . All the elastic deformation parts  662  are bent so as to become closer to the center line of the screw member  650  with decreasing distance to the free end. 
     As described above, the rotating engagement part  656  penetrates the screw member  650 . More specifically, the rotating engagement part  656  penetrates the screw body part  660 . That is, the through hole penetrating the screw body part  660  constitutes a part of the rotating engagement part  656 . Furthermore, an inner surface  668  of the elastic deformation part  662  also constitutes a part of the rotating engagement part  656 . The inner surface  668  is continuous with the through hole penetrating the screw body part  660 . 
     The sleeve  450  has a shaft hole  452 . A shaft is inserted and bonded to the shaft hole  452 . In  FIG. 32  and  FIG. 33 , the illustration of the shaft is omitted. 
     The sleeve  450  has a sleeve-side connection part  460 . The sleeve-side connection part  460  has a cylindrical shape. The sleeve-side connection part  460  has a hollow portion  461  and an inner surface  462 . The hollow portion  461  is opened to the screw member  650  side. The inner side of the inner surface  462  constitutes the hollow portion  461 . The inner surface  462  defines the hollow portion  461 . The inner surface  462  is a circumferential surface. The inner surface  462  has an engagement recess  464 . The engagement recess  464  is a circumferential groove. 
       FIG. 32  and  FIG. 33  show a wrench  680  used for rotating the screw member  650 . The sectional shape of the wrench  680  corresponds to the sectional shape of the rotating engagement part  656 . The sectional shape of the wrench  680  is a tetragon (square). As shown in  FIG. 32  and  FIG. 33 , the screw-connection between the male screw part  654  and the female screw part  220  is enabled by inserting the wrench  680  into the rotating engagement part  656  and rotating the wrench  680 . 
     As shown in  FIG. 32 , in a state in which an external force is not applied, the elastic deformation part  662  is bent. The state in which an external force is not applied is also referred to as a natural state. In  FIG. 32 , the wrench  680  is shallowly inserted. The wrench  680  remains at the screw body part  660 , and has not reached the inside of the elastic deformation part  662 . Therefore, the wrench  680  does not abut on the elastic deformation part  662 , and thus does not elastically deform the elastic deformation part  662 . An insertion position at which the elastic deformation part  662  is not elastically deformed is also referred to as a first insertion position Ps. 
     On the other hand, as shown in  FIG. 33 , the elastic deformation part  662  abuts on the wrench  680  when the wrench  680  is deeply inserted. As a result, the elastic deformation part  662  is elastically deformed so as to extend along the wrench  680 . The elastic deformation part  662  is straightened by the elastic deformation. The elastic deformation causes the engagement projection  664  of the elastic deformation part  662  to reach a position at which the engagement projection  664  is engaged with the engagement recess  464  of the sleeve-side connection part  460 . An insertion position at which the engagement projection  664  is engaged with the engagement recess  464  is also referred to as a second insertion position Pd. 
     Although a gap is present between the elastic deformation part  662  and the wrench  680  in  FIG. 33 , the gap is not actually present. The elastic deformation part  662  is deformed to the outer side by abutting on the wrench  680 , and is thereby straightened. 
     Such a screw member  650  can also fulfill the same function as that of the above-described screw member  600 . To press the sleeve  450  in the engaging direction, the screw member  650  is screwed into the female screw part of the head. At this time, the wrench  680  is inserted shallowly. That is, the wrench  680  is positioned at the first insertion position Ps. While maintaining the shallow insertion (first insertion position Ps), the screw member  650  is rotated in the first direction DR 1 . Then, the screw-connection of the screw member  650  progresses while the natural state of the elastic deformation part  662  is maintained. In the elastic deformation part  662  in the natural state, the engagement projection  664  is positioned on the inner side of the inner surface  462 . Therefore, the elastic deformation part  662  is smoothly inserted inside the sleeve-side connection part  460 . Finally, a lower end surface  470  of the sleeve-side connection part  460  abuts on an abutting surface  666  of the screw member  650 , whereby the sleeve  450  is pressed in the engaging direction. 
     To remove the screw member  650 , the wrench  680  is inserted deeply. That is, the wrench  680  is positioned at the second insertion position Pd ( FIG. 33 ). This insertion causes the elastic deformation part  662  to be elastically deformed, whereby the engagement projection  664  is engaged with (caught by) the engagement recess  464 . That is, the screw member  650  is connected to the sleeve  450 . While maintaining the deep insertion (second insertion position Pd), the screw member  650  is rotated in the second direction DR 2 . Then, the screw member  650  is moved to the lower side while the connection between the screw member  650  and the sleeve  450  is maintained. As a result, the tip engagement part RT including the sleeve  450  is pulled out from the hosel hole  204 . The connection between the screw member  650  and the sleeve  450  can be easily released by inserting the wrench  680  shallowly. 
     Thus, the connection can be easily released. The connection may be released upon confirmation of pulling out of the tip engagement part RT including the sleeve  450  from the hosel hole  204 . 
     As explained above, the screw member  650  includes: the screw body part  660  having the male screw part  654 ; the elastic deformation part  662  extending from the screw body part  660  to the sleeve side (upper side) and constituting the screw-side connection part  652 ; and the rotating engagement part  656  to which a wrench  680  for rotating the screw member  650  can be inserted. The rotating engagement part  656  has a through hole  658  penetrating the screw body part  660 , and an inner surface  668  of the elastic deformation part  662  that extends continuously with the through hole  658 . The elastic deformation part  662  has the engagement projection  664  at an end portion thereof on the sleeve side, and the end portion on the sleeve side is a free end. The sleeve-side connection part  460  has the hollow portion  461  opened on the screw member  650  side, the inner surface  462  defining the hollow portion  461 , and the engagement recess  464  provided on the inner surface  462 . In a natural state, the elastic deformation part  662  including the engagement projection  664  exhibits a shape that can be inserted to the hollow portion  461  with rotation of the screw member  650  in the first direction DR 1 . When the wrench  680  is inserted to a position at which the wrench  680  abuts on the inner surface  668  of the elastic deformation part  662 , the elastic deformation part  662  is elastically deformed so as to be positioned at a position at which the engagement projection  664  of the elastic deformation part  662  can be engaged with the engagement recess  464 . 
     With this configuration, the wrench  680  can be inserted shallowly when rotating the screw member  650  in the first direction DR 1 , whereby the pressing of the tip engagement part RT is enabled. The wrench  680  can be inserted deeply when rotating the screw member  650  in the second direction DR 2 , whereby the pulling out of the tip engagement part RT is enabled. 
     A modification example of the embodiment shown in  FIG. 32  and  FIG. 33  is also possible. In the present modification example, the configuration of the embodiment shown in  FIG. 30  and  FIG. 31  is applied to the embodiment shown in  FIG. 32  and  FIG. 33 . In the present modification example, engagement using the engagement ball  634  is used in place of the engagement using the elastic deformation part  662  and the engagement projection  664 . In the present modification example, the engagement ball  634  is disposed at the screw-side connection part  652 . The engagement ball  634  is disposed at the position corresponding to the engagement projection  664 . When the wrench  680  is inserted deeply, the engagement ball  634  is pressed by the wrench  680  from inside so as to be projected outside, and is thereby engaged with the engagement recess  464 . By this engagement, the screw member  650  is connected to the sleeve  450 . Therefore, when the screw member is rotated in the second direction DR 2  while maintaining the deep insertion of the wrench  680 , the sleeve  450  is pulled in the engagement releasing direction. When the wrench  680  is inserted shallowly, the abutment between the wrench  680  and the engagement ball  634  is released so as to bring about a state in which the engagement ball  634  can be retracted inside. By bringing about this state, the connection between the sleeve  450  and the screw member  650  can be released. The screw-side connection part  652  is configured such that the engagement ball  634  does not fall off from the screw-side connection part  652  even in a state in which the wrench  680  is not present. For example, the engagement ball  634  may be disposed in a ball housing hole  636  provided on the screw-side connection part  652 , and (small) stoppers to prevent the falling-off of the engagement ball  634  may be provided on both sides of the ball housing hole  636 . 
     As shown in  FIG. 12  to  FIG. 17  and so forth, the position of the sleeve on the sole side is changed by the above-described angle adjustment. That is, when a spacer that makes the sleeve inclined is used, the position of the lower end of the sleeve is changed. For this reason, the position of the sleeve-side connection part may also be changed. The connecting mechanism of the sleeve-side connection part and the screw member preferably has a mechanism capable of absorbing the position change of the lower end of the sleeve. The sleeve preferably has a displacement mechanism in which the sleeve-side connection part can be displaced with respect to the sleeve body so as to correspond to the position change of the lower end of the sleeve. The displacement mechanism is preferably configured to enable the connection between the sleeve-side connection part and the screw member over the entire movement range of the lower end of the sleeve. 
       FIG. 34  and  FIG. 35  are sectional views of an embodiment including a sleeve sv 1  having the above-described displacement mechanism and a screw member  600   a  corresponding to the sleeve sv 1 . In the present embodiment, one spacer sp 1  is used. 
     The sleeve sv 1  has a sleeve body sv 2  and a movable connection part sv 3 . The sleeve body sv 2  has a movable space r 1 . The sleeve body sv 2  further has an opening r 2  that allows communication between the movable space r 1  and the outside. The movable space r 1  and the opening r 2  are provided at a bottom surface portion of the sleeve body sv 2 . 
     The movable connection part sv 3  has a body sv 31 , a falling-off prevention part sv 32 , and a joining part sv 33 . 
     The body sv 31  constitutes a sleeve-side connection part. The body sv 31  has a tip tapered surface tp 1 . Except for the presence of the tip tapered surface tp 1 , the outer shape of the body sv 31  is the same as that of the above-described sleeve-side connection part  410 . 
     The falling-off prevention part sv 32  is disposed in the movable space r 1 . The falling-off prevention part sv 32  can move inside the movable space r 1 . 
     The joining part sv 33  joins the body sv 31  to the falling-off prevention part sv 32 . 
     The joining part sv 33  penetrates the opening r 2 . The sectional area of the opening r 2  is larger than the sectional area of the joining part sv 33 . The joining part sv 33  can be moved inside the opening r 2 . The movable space r 1  has a dimension that can ensure the necessary movement and inclination of the falling-off prevention part sv 32 . The falling-off prevention part sv 32  has a size that cannot pass through the opening r 2 . 
     The movable connection part sv 3  is held by the sleeve body sv 2  in a state in which it hangs from the sleeve body sv 2 . The movable connection part sv 3  can be moved relative to the sleeve body sv 2  within a range that can follow the position change of the sleeve on the sole side. The movable connection part sv 3  can be inclined relative to the sleeve body sv 2  within a range that can follow the position change of the sleeve on the sole side. 
     The screw member  600   a  has a receiving slope  690 . The receiving slope  690  is a conical concave surface. Except for the presence of the receiving slope  690 , the screw member  600   a  is the same as the above-described screw member  600 . The receiving slope  690  is provided at an upper end surface of the second member  622  (see  FIG. 31 ). The receiving slope  690  is inclined outward as going to the upper side. 
     In state (a) in  FIG. 34 , the center line of the outer surface of the sleeve sv 1  is shifted to the right side with respect to the center line of the screw member  600   a . However, the movable connection part sv 3  can be moved so as to absorb the shift between the center lines. As a result of the movement, the screw member  600   a  can be connected to the sleeve sv 1 . That is, state (b) in  FIG. 34  is realized. The abutment between the tip tapered surface tp 1  and the receiving slope  690  contributes to smooth movement of the movable connection part sv 3 . 
     In state (a) in  FIG. 35 , the center line of the outer surface of the sleeve sv 1  is shifted to the left side with respect to the center line of the screw member  600   a . In this case as well, the movable connection part sv 3  can be moved so as to absorb the shift between the center lines. As a result of the movement, the screw member  600   a  can be connected to the sleeve sv 1 . That is, state (b) in  FIG. 35  is realized. The abutment between the tip tapered surface tp 1  and the receiving slope  690  contributes to smooth movement of the movable connection part sv 3 . 
     As explained above, the sleeve sv 1  has a sleeve body sv 2  and a movable connection part sv 3 , and the movable connection part sv 3  is configured to be movable with respect to the sleeve body sv 2 . When the screw member  600   a  is rotated in the first direction, an upper end portion of the screw member and a lower end portion of the movable connection part abut on each other. By the abutment, the movable connection part is moved to a position at which it can be connected to the screw member  600   a . Therefore, the sleeve and the screw member can be connected to each other even when the position of the lower end of the sleeve is changed. 
     Each of the above-described screw members plays the role (role A) of pressing the tip engagement part RT in the engaging direction, and the role (role B) of pulling the tip engagement part RT in the engagement releasing direction. These screw members can also be used to play only the role B. For example, the role A can be replaced by another screw member that does not have the connecting function to the sleeve. A screw member having the above-described connecting function can be used only when the tip engagement part RT is removed from the reverse-tapered hole. In this case, the screw member mounted to the golf club being used can be a screw member that does not have the connecting function, so that the weight of the golf club can be reduced. 
     The material of the sleeve is not limited. Preferable examples of the material include a titanium alloy, stainless steel, an aluminum alloy, a magnesium alloy, and a resin. From the viewpoint of strength and lightweight properties, for example, the aluminum alloy and the titanium alloy are more preferable. It is preferable that the resin has excellent mechanical strength. For example, the resin is preferably a resin referred to as an engineering plastic or a super-engineering plastic. 
     The material of the spacer is not limited. Preferable examples of the material include a titanium alloy, stainless steel, an aluminum alloy, a magnesium alloy, and a resin. From the viewpoint of strength and lightweight properties, for example, the aluminum alloy and the titanium alloy are more preferable. It is preferable that the resin has excellent mechanical strength. For example, the resin is preferably a resin referred to as an engineering plastic or a super-engineering plastic. From the viewpoint of moldability, the resin is preferable. 
     As described above, the golf clubs may include an adjusting mechanism capable of adjusting the position and/or angle of the center line of the shaft. The adjusting mechanism includes a connecting mechanism between a screw member and a sleeve. This mechanism preferably satisfies the Golf Rules defined by The R&amp;A (The Royal and Ancient Golf Club of St Andrews). That is, the mechanism preferably satisfies requirements specified in “lb. Adjustability” in “1. Clubs” of “Appendix II. Design of Clubs” defined by The R&amp;A. The requirements specified in “lb. Adjustability” are the following items (i), (ii), and (iii): 
     (i) the adjustment cannot be readily made; 
     (ii) all adjustable parts are firmly fixed and there is no reasonable likelihood of them becoming loose during a round; and 
     (iii) all configurations of adjustment conform to the Rules. 
     The disclosure described above can be applied to all golf clubs such as a wood type golf club, a hybrid type golf club, an iron type golf club, and a putter. 
     The above description merely shows illustrative examples, and various modifications can be made.