Patent Publication Number: US-10307646-B2

Title: Golf club

Description:
The present application claims priority on Patent Application No. 2016-257165 filed in JAPAN on Dec. 29, 2016, 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 in which a shaft is detachably attached to a head has been proposed. As disclosed in US2009/0286618 and U.S. Pat. No. 9,364,723, a sleeve is fixed to the tip end portion of a shaft, and the sleeve is fixed to a head with a screw. In these golf clubs, a mechanism (rotation-preventing mechanism) for preventing a rotation of the sleeve with respect to the head is used. 
     SUMMARY OF THE INVENTION 
     It was considered that the rotation-preventing mechanism in above-mentioned literatures functions completely. However, the inventor of the present application has found that there is room to improve the rotation-preventing mechanism. 
     The present disclosure shows a golf club in which a shaft is detachably attached to a head and which can eliminate a strange feeling upon impact. 
     In one aspect, a golf club may include a shaft, a head having a hosel hole, a sleeve fixed to a tip end portion of the shaft, and a screw which can be screw-connected to the sleeve. The sleeve may have an engaging projection part. The head may have an engaging recess part. A rotation of the sleeve with respect to the hosel hole may be regulated based on an engagement between the engaging projection part and the engaging recess part. Falling off of the sleeve from the hosel hole may be regulated based on a connection between the screw and the sleeve inserted into the hosel hole. The engaging projection part may have a first side surface located on a side which receives a rotating force caused by hitting, a second side surface located on an opposite side to the first side surface, and an outer surface which extends between the first side surface and the second side surface. The engaging recess part may have a first opposed surface opposed to the first side surface, a second opposed surface opposed to the second side surface, and an inner surface opposed to the outer surface. The engaging projection part may have a tapered projection part formed such that a distance between the first side surface and the second side surface decreases toward a tip end of the sleeve. The tapered projection part may have a maximum width of equal to or greater than an opening width of the engaging recess part. The outer surface may have an outer inclination surface inclined so as to go toward a radial-direction inner side as approaching to the tip end of the sleeve. 
     In another aspect, the engaging recess part may have a tapered recess part formed such that a distance between the first opposed surface and the second opposed surface decreases toward the tip end of the sleeve. 
     In another aspect, the inner surface may have an inner inclination surface inclined so as to go toward the radial-direction inner side as approaching to the tip end of the sleeve. 
     In another aspect, at least one of the first side surface and the first opposed surface may extend along an axial direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a golf club according to a first embodiment; 
         FIG. 2  is an exploded view of the golf club in  FIG. 1 ; 
         FIG. 3  is a sectional view of the golf club in  FIG. 1 ; 
         FIG. 4  is a perspective view of a head according to the first embodiment; 
         FIG. 5  is a plan view of the head in the vicinity of a hosel according to the first embodiment; 
         FIG. 6  is a sectional view of a head body according to the first embodiment; 
         FIG. 7  is a perspective view of a sleeve according to the first embodiment; 
         FIG. 8  is a side view of the sleeve in  FIG. 7 ; 
         FIG. 9  is a bottom view of the sleeve in  FIG. 7 ; 
         FIG. 10  is a sectional view of the sleeve in  FIG. 7 ; 
         FIG. 11  is a sectional view taken along line A-A in  FIG. 8 ; 
         FIG. 12  shows a golf club according to a second embodiment; 
         FIG. 13  is an exploded view of the golf club in  FIG. 12 ; 
         FIG. 14  is a sectional view of the golf club in  FIG. 12 ; 
         FIG. 15  is a sectional view of a head body according to the second embodiment; 
         FIG. 16  is a perspective view of a sleeve according to the second embodiment; 
         FIG. 17  is a side view of the sleeve in  FIG. 16 ; 
         FIG. 18  is a bottom view of the sleeve in  FIG. 16 ; 
         FIG. 19  is a sectional view of the sleeve in  FIG. 16 ; 
         FIG. 20  is a sectional view taken along line A-A in  FIG. 19 ; 
         FIG. 21  is a side view of an engaging member according to the second embodiment, 
         FIG. 22  is a plan view of the engaging member in  FIG. 21 ; 
         FIG. 23  is a side view of the sleeve according to another embodiment; 
         FIG. 24  is a sectional view of a head body according to the embodiment of  FIG. 23 ; 
         FIG. 25  is a schematic view showing an engaging projection part and an engaging recess part according to another embodiment; 
         FIG. 26( a )  is a schematic view showing an engaging projection part and an engaging recess part according to another embodiment;  FIG. 26( b )  is a schematic view showing an engaging projection part and an engaging recess part according to another embodiment, and  FIG. 26( c )  is a schematic view showing an engaging projection part and an engaging recess part according to another embodiment; and 
         FIG. 27( a )  is a schematic view showing an engaging projection part and an engaging recess part according to another embodiment, and  FIG. 27( b )  is a schematic view showing an engaging projection part and an engaging recess part according to another embodiment. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, the present disclosure will be described in detail according to the preferred embodiments with appropriate references to the accompanying drawings. 
     Unless otherwise described, “an axial direction” in the present application means a direction of a center line of a hosel hole. The axial direction is the direction of a center line z 1  explained later. Unless otherwise described, “a radial direction” in the present application means a radial direction of the hosel hole. Unless otherwise described, “a lower side” in the present application means an axial-direction sole side, and “an upper side” means an axial-direction grip side. 
     First Embodiment 
       FIG. 1  shows a golf club  2  according to a first embodiment.  FIG. 1  shows only the vicinity of a head of the golf club  2 .  FIG. 2  is an exploded view of the golf club  2 . In  FIG. 2 , a shaft and a grip are not shown.  FIG. 3  is a sectional view of the golf club  2 .  FIG. 3  is a sectional view taken along a center line of a sleeve  8 . 
     The golf club  2  has a head  4 , a shaft  6 , the sleeve  8 , and a screw  10 . As shown in  FIG. 2 , the golf club  2  further has an intermediate member  14  and a washer  16 . 
     The head  4  has a face  4   a , a crown  4   b , a sole  4   c , and a hosel  4   d.    
     The head  4  is a wood type head. The head  4  is a driver head. The type of the head  4  is not limited in the present disclosure. Examples of the head  4  include a wood type head, a utility type head, a hybrid type head, an iron type head, and a putter head. The shaft  6  is not limited, and a carbon shaft, a steel shaft, etc. which have been generally used may be used. 
     The sleeve  8  is fixed to a tip end portion of the shaft  6 . The method of the fixation is adhesion with an adhesive. A grip which is not shown in the drawings is attached to a butt end portion of the shaft  6 . The shaft  6  and the sleeve  8  are fixed to each other to form a shaft  12  with the sleeve. 
     The screw  10  has a male screw part  10   a  and a head part  10   b . The male screw part  10   a  can be screw-connected to a screw hole Ht of the sleeve  8 . The head part  10   b  has a recess part  10   c  which receives a tool. In  FIG. 2  and  FIG. 3 , a male screw of the male screw part  10   a  is not depicted. 
     The sleeve  8  (shaft  12  with the sleeve) is fixed to the head  4  by tightening the screw  10 . This fixed state is also referred to as a connected state in the present application.  FIG. 3  is a sectional view in the connected state. The fixation between the head  4  and the shaft  12  with the sleeve is released by loosening the screw  10 . This released state from the fixation is also referred to as a separated state in the present application. The shaft  6  is detachably attached to the head  4 . 
     Unless otherwise described, structures shown in the present application mean a structure in the connected state. 
     The intermediate member  14  is a ring-shaped member. The outer surface of the intermediate member  14  is a circumferential surface. Although not shown in the drawings, the inner surface of the intermediate member  14  forms a female screw. The intermediate member  14  has a function of preventing the screw  10  from falling off. This function is detailed later. 
     Needless to say, the intermediate member  14  may not be present. When a falling-off prevention function for the screw  10  is unnecessary, the intermediate member  14  is also unnecessary. Even when a falling-off prevention function for the screw  10  is required, the intermediate member  14  might be unnecessary. For example, a head body  18  may include a flange having the same shape as the shape of the intermediate member  14 . An O-ring may be used instead of the intermediate member  14 . A falling-off prevention function can be fulfilled by setting the inner diameter of the O-ring such that the male screw part  10   a  of the screw  10  is inserted into and retained by the O-ring. 
       FIG. 4  is a perspective view showing a hosel part of the head  4 .  FIG. 5  is a plan view of the hosel part of the head  4 .  FIG. 6  is a sectional view of the head body  18 . 
     The head  4  is a hollow golf club head. The head  4  has the head body  18  and a cylindrical member  20  (see  FIG. 2 ). 
     The head body  18  has a hosel hole  22  (see  FIG. 4 ,  FIG. 5 , and  FIG. 6 ). The sleeve  8  is inserted to the hosel hole  22 . The sleeve  8  is supported by the hosel hole  22  in the connected state. The head body  18  has a through-hole  24  to which the screw  10  is inserted (see  FIG. 3  and  FIG. 6 ). The through-hole  24  penetrates through a bottom part of the hosel hole  22  to reach the sole. The through-hole  24  is opened toward the lower side. 
     As shown in  FIG. 3  and  FIG. 6 , the head body  18  has a flange  26 . In the connected state, the flange  26  is located on the lower side of the sleeve  8 . As shown in  FIG. 3 , the inner diameter of the flange  26  is greater than the outer diameter of the washer  16 . As shown in  FIG. 3 , the outer diameter of the intermediate member  14  is greater than the inner diameter of the flange  26 . 
     As shown in  FIG. 4 ,  FIG. 5 , and  FIG. 6 , the head  4  (hosel hole  22 ) has an engaging recess part R 1 . The engaging recess part R 1  is provided on (the inner surface of) the hosel hole  22 . The engaging recess part R 1  is provided at an upper end of the hosel hole  22 . 
     A plurality of engaging recess parts R 1  are provided. The engaging recess parts R 1  are arranged at equal intervals in a circumferential direction. The engaging recess parts R 1  are arranged at intervals of a predetermined angle in the circumferential direction. In the present embodiment, four engaging recess parts R 1  are provided. The engaging recess parts R 1  are arranged at 90-degree intervals in the circumferential direction. The plurality of (four) engaging recess parts R 1  have the same shape. The plurality of engaging recess parts R 1  are varied only in their circumferential-direction positions. 
     The outer surface of the cylindrical member  20  is a circumferential surface. As shown in  FIG. 2 , the outer surface of the cylindrical member  20  has a larger-diameter part and a smaller-diameter part. Although not shown in the drawing, the inner surface of the cylindrical member  20  is a circumferential surface. The inner diameter of the circumferential surface corresponds to the outer diameter of a lower part  34  (described later) of the sleeve  8 . 
     Needless to say, the cylindrical member  20  may not be present. For example, the head body  18  may have a shape equivalent to the cylindrical member  20 . Since a middle part  32  of the sleeve  8  is supported by the hosel hole  22 , there is no problem even if there is no support by the cylindrical member  20 . 
       FIG. 7  is a perspective view of the sleeve  8 .  FIG. 8  is a side view of the sleeve  8 .  FIG. 9  is a bottom view of the sleeve  8 .  FIG. 10  is a sectional view of the sleeve  8 .  FIG. 11  is a sectional view taken along line A-A in  FIG. 8 . 
     The sleeve  8  has an upper part  30 , the middle part  32 , and the lower part  34 . A step surface  36  exists at a boundary between the upper part  30  and the middle part  32 . The sleeve  8  has a shaft hole Hs and the screw hole Ht. The shaft hole Hs is located inside the upper part  30  and the middle part  32 . The shaft hole Hs is opened toward one side (upper side) of the sleeve  8 . The screw hole Ht is opened toward the other side (lower side) of the sleeve  8 . The screw hole Ht is located inside the lower part  34 . 
     The upper part  30  is exposed in the connected state. In the connected state, the step surface  36  does not abut on a hosel end surface  40  of the head  4 . A (slight) gap is present between the step surface  36  and the hosel end surface  40 . Upper ends of the engaging recess parts R 1  are located at the hosel end surface  40 . 
     As shown in  FIG. 1 , the outer diameter of a lower end of the upper part  30  is substantially equal to the outer diameter of the hosel end surface  40 . In the connected state, the upper part  30  has an appearance like a ferrule. In the connected state, the middle part  32  and the lower part  34  are located inside the hosel hole  22 . 
     The outer surface of the middle part  32  of the sleeve  8  has a circumferential surface  50 . In the connected state, the circumferential surface  50  is brought into contact with the hosel hole  22 . The circumferential surface  50  is brought into surface-contact with a circumferential surface of the hosel hole  22 . This contact contributes to holding of the sleeve  8 . 
     The outer surface of the lower part  34  of the sleeve  8  is a circumferential surface. The lower part  34  of the sleeve  8  has a screw-hole containing part  52 . The screw-hole containing part  52  contains the screw hole Ht inside thereof. In  FIG. 10 , a female screw in the screw hole Ht is not depicted. 
     As shown in  FIG. 10 , a center line h 1  of the shaft hole Hs is inclined with respect to a center line z 1  of the outer surface (circumferential surface  50 ) of the sleeve  8 . An inclination angle  81  shown in  FIG. 10  is an angle between the center line h 1  and the center line z 1 . In the connected state, the center line z 1  is equal to the center line of the hosel hole  22 . The center line h 1  of the shaft hole Hs is equal to the center line of the shaft  6 . A loft angle, a lie angle, and a face angle can be adjusted by the inclination angle θ 1 . 
     The sleeve  8  has an engaging projection part P 1 . The engaging projection part P 1  is provided on an outer circumferential surface of the sleeve  8 . The engaging projection part P 1  is provided on the circumferential surface  50 . The engaging projection part P 1  is provided at an upper end of the circumferential surface  50 . An upper end of the engaging projection part P 1  is located at the step surface  36 . 
     A plurality of engaging projection parts P 1  are provided on the sleeve  8 . The engaging projection parts P 1  are arranged at equal intervals in the circumferential direction. The engaging projection parts P 1  are arranged at intervals of a predetermined angle in the circumferential direction. In the present embodiment, four engaging projection parts P 1  are provided. The engaging projection parts P 1  are arranged at 90-degree intervals in the circumferential direction. The plurality of (four) engaging projection parts P 1  have the same shape. The plurality of engaging projection parts P 1  are varied only in their circumferential-direction positions. 
     These engaging projection parts P 1  are engaged with the above-mentioned engaging recess parts R 1 . The engaging projection parts P 1  are engaged with the respective engaging recess parts R 1 . A rotation of the sleeve  8  with respect to the head  4  is regulated by the engagement. 
     As shown in  FIG. 3 , the cylindrical member  20  is fixed to (a lower part of) the hosel hole  22 . The fixation can be attained by adhesion, welding, etc. The lower part  34  of the sleeve  8  is inserted to the cylindrical member  20  in the connected state. The cylindrical member  20  supports the lower part  34 . 
     As shown in  FIG. 3 , the intermediate member  14  is located between the cylindrical member  20  and the flange  26 . An axial-direction distance between the cylindrical member  20  and the flange  26  is greater than an axial-direction length of the intermediate member  14 . The intermediate member  14  is not fixed to the hosel hole  22 . The intermediate member  14  can move between the cylindrical member  20  and the flange  26 . 
     In the connected state shown in  FIG. 3 , an axial force caused by tightening the screw  10  is transmitted to the cylindrical member  20  through the washer  16  and the intermediate member  14 . The cylindrical member  20  receives the upward axial force. 
     The intermediate member  14  prevents the screw  10  in the separated state from falling off. The screw  10  is tightened in the connected state shown in  FIG. 3 . The screw  10  moves toward the lower side with respect to the sleeve  8  as the screw  10  is loosened. When the screw  10  is further loosened, the male screw part  10   a  of the screw  10  reaches the intermediate member  14 . As above mentioned, the inner surface of the intermediate member  14  is a female screw. The female screw conforms to the male screw part  10   a . When the screw  10  is further loosened, the male screw part  10   a  is screw-connected to the intermediate member  14 . When the male screw part  10   a  comes out of the screw hole Ht, the male screw part  10   a  is screw-connected to the intermediate member  14 . Even when the male screw part  10   a  is come out of the screw hole Ht and the shaft  12  with the sleeve is detached from the head  4 , the screw  10  which is screw-connected to the intermediate member  14  does not fall off from the head  4 . Since the screw  10  is held by the head  4 , re-connection can be performed smoothly. In addition, the loss of the screw  10  is prevented. 
     Second Embodiment 
       FIG. 12  is a front view of a golf club  102  according to a second embodiment.  FIG. 12  shows only the vicinity of a head of the golf club  102 .  FIG. 13  is an exploded view of the golf club  102 . A shaft and a grip are not shown in  FIG. 13 .  FIG. 14  is a sectional view of the golf club  102 .  FIG. 14  is a sectional view taken along a center line of a sleeve  108 . 
     The golf club  102  has a head  104 , a shaft  106 , the sleeve  108 , and a screw  110 . As shown in  FIG. 13 , the golf club  102  further has an intermediate member  114  and a washer  116 . 
     The head  104  has a face  104   a , a crown  104   b , a sole  104   c , and a hosel  104   d.    
     The head  104  is a wood type head. The head  104  is a driver head. The type of the head  104  is not limited in the present disclosure. Examples of the head  104  include a wood type head, a utility type head, a hybrid type head, an iron type head, and a putter head. The shaft  106  is not limited, and a carbon shaft, a steel shaft, etc. which have been generally used may be used. 
     The sleeve  108  is fixed to a tip end portion of the shaft  106 . A grip which is not shown in the drawings is attached to a butt end portion of the shaft  106 . The shaft  106  and the sleeve  108  are fixed to each other to form a shaft  112  with the sleeve. 
     The screw  110  has a male screw part  110   a  and a head part  110   b . The male screw part  110   a  can be screw-connected to a screw hole Ht of the sleeve  108 . The head part  110   b  has a recess part  110   c  which receives a tool. In  FIG. 13  and  FIG. 14 , a male screw of the male screw part  110   a  is not depicted. 
     The sleeve  108  (shaft  112  with the sleeve) is fixed to the head  104  by tightening the screw  110  thereby to achieve the connected state.  FIG. 14  is a sectional view in the connected state. The fixation between the head  104  and the shaft  112  with the sleeve is released by loosening the screw  110  thereby to achieve the separated state. The shaft  106  is detachably attached to the head  104 . 
     The intermediate member  114  is a ring-shaped member. The outer surface of the intermediate member  114  is a circumferential surface. Although not shown in the drawings, the inner surface of the intermediate member  114  forms a female screw. The intermediate member  114  has a function of preventing the screw  110  from falling off. This function is detailed later. 
     Needless to say, the intermediate member  114  may not be present. When a falling-off prevention function for the screw  110  is unnecessary, the intermediate member  114  is also unnecessary. Even if a falling-off prevention function for the screw  110  is required, the intermediate member  114  might be unnecessary. For example, a head body  118  may have a flange having the same shape as the shape of the intermediate member  114 . An O-ring may be used instead of the intermediate member  114 . A falling-off prevention function can be fulfilled by setting the inner diameter of the O-ring such that the male screw part  110   a  of the screw  110  is inserted into and retained by the O-ring. 
     As shown in  FIG. 13  and  FIG. 14 , the head  104  has the head body  118  and an engaging member  120 . 
       FIG. 14  is a sectional view of the head body  118 . 
     The head body  118  has a hosel hole  122  (see  FIG. 14  and  FIG. 15 ). The sleeve  108  is inserted to the hosel hole  122 . The head body  118  has a through-hole  124  to which the screw  110  is inserted. The through-hole  124  penetrates through a bottom part of the hosel hole  122  to reach the sole. The through-hole  124  is opened toward the lower side. The head body  118  has a hollow part. 
     As shown in  FIG. 15 , the head body  118  has a flange  126 . In the connected state, the flange  126  is located on the lower side of the sleeve  108 . As shown in  FIG. 14 , the inner diameter of the flange  126  is greater than the outer diameter of the washer  116 . As shown in  FIG. 14 , the outer diameter of the intermediate member  114  is greater than the inner diameter of the flange  126 . 
     As shown in  FIG. 13  and  FIG. 14 , the engaging member  120  has an outer surface  120   a  and an inner surface  120   b . The outer surface  120   a  is a circumferential surface. The outer surface  120   a  has a shape corresponding to a shape of the hosel hole  122  at a position where the engaging member  120  is fixed to the hosel hole  122 . The inner surface  120   b  is a circumferential surface. The inner diameter of the circumferential surface  120   b  corresponds to the outer diameter of a circumferential outer surface  135  provided on a lower part  134  (described later) of the sleeve  108 . The engaging member  120  is fixed to the head body  118 . 
     As shown in  FIG. 13 , the engaging member  120  has an engaging recess part R 1 . The engaging recess part R 1  is formed on an upper end surface of the engaging member  120 . The engaging member  120  is fixed to the head body  118  to form the engaging recess part R 1  in the head  104 . 
     Needless to say, the engaging member  120  may not be present. For example, the engaging member  120  may be integrated with the head body  118 . In other words, the head body  118  may have a shape equivalent to the engaging member  120 . 
       FIG. 16  is a perspective view of the sleeve  108 .  FIG. 17  is a side view of the sleeve  108 .  FIG. 18  is a bottom view of the sleeve  108 .  FIG. 19  is a sectional view of the sleeve  108 .  FIG. 20  is a sectional view taken along line A-A in  FIG. 19 .  FIG. 21  is a side view of the engaging member  120 .  FIG. 22  is a plan view of the engaging member  120 . 
     The sleeve  108  has an upper part  130 , a middle part  132 , and the lower part  134 . A step surface  136  is present on a boundary between the upper part  130  and the middle part  132 . A step surface  138  is present on a boundary between the middle part  132  and the lower part  134 . 
     The sleeve  108  has a shaft hole Hs and the screw hole Ht. The shaft hole Hs is located inside the upper part  130  and the middle part  132 . The shaft hole Hs is opened toward one side (upper side) of the sleeve  108 . The screw hole Ht is opened toward the other side (lower side) of the sleeve  108 . The screw hole Ht is located inside the lower part  134 . 
     In the connected state, the upper part  130  is exposed (see  FIG. 12 ). In the connected state, the step surface  136  does not abut on a hosel end surface  140  of the head  104 . A (slight) gap is present between the step surface  136  and the hosel end surface  140 . 
     As shown in  FIG. 12 , the outer diameter of a lower end of the upper part  130  is substantially equal to the outer diameter of the hosel end surface  140 . In the connected state, the upper part  130  has an appearance like a ferrule. In the connected state, the middle part  132  and the lower part  134  are located inside the hosel hole  122 . 
     The outer surface of the middle part  132  of the sleeve  108  has a circumferential surface  150 . In the connected state, the circumferential surface  150  is brought into contact with the hosel hole  122 . The circumferential surface  150  is brought into surface-contact with a circumferential surface  122   a  of the hosel hole  122 . This contact contributes to holding of the sleeve  108 . 
     As well shown in  FIG. 16  and  FIG. 17 , the sleeve  108  has an engaging projection part P 1 . The engaging projection part P 1  is provided on the lower part  134  of the sleeve  108 . The outer surface of the lower part  134  has a circumferential outer surface  135 . The circumferential outer surface  135  is brought into contact with the inner surface  120   b  of the engaging member  120  ( FIG. 14 ). The lower part  134  of the sleeve  108  has a screw-hole containing part  152 . The screw-hole containing part  152  includes the screw hole Ht. In  FIG. 19 , a female screw in the screw hole Ht is not depicted. 
     As shown in  FIG. 19 , a center line h 1  of the shaft hole Hs is inclined with respect to a center line z 1  of the outer surface (circumferential surface  150 ) of the sleeve  108 . An inclination angle  81  shown in  FIG. 19  is an angle between the center line h 1  and the center line z 1 . In the connected state, the center line z 1  is equal to the center line of the hosel hole  122 . The center line h 1  of the shaft hole Hs is equal to the center line of the shaft  106 . A loft angle, a lie angle, and a face angle can be adjusted by the inclination angle  81 . 
     The sleeve  108  has the engaging projection part P 1 . The engaging projection part P 1  is provided on an outer circumferential surface of the sleeve  108 . The engaging projection part P 1  is provided on the circumferential surface  135 . The engaging projection part P 1  is provided on the lower part  134 . The engaging projection part P 1  is provided at an upper end of the lower part  134 . An upper end of the engaging projection part P 1  is located at the step surface  138 . 
     A plurality of engaging projection parts P 1  are provided on the sleeve  108 . As well shown in  FIG. 18 , the plurality of engaging projection parts P 1  are arranged at equal intervals in the circumferential direction. The engaging projection parts P 1  are arranged at intervals of a predetermined angle in the circumferential direction. In the present embodiment, four engaging projection parts P 1  are provided. The engaging projection parts P 1  are arranged at 90-degree intervals in the circumferential direction. The plurality of (four) engaging projection parts P 1  have the same shape. The plurality of engaging projection parts P 1  are varied only in their circumferential-direction positions. 
     As shown in  FIG. 21 , the engaging recess part R 1  is formed toward the lower side from an upper end surface  120   c  of the engaging member  120 . In the engaging member  120 , the engaging recess part R 1  is formed as a cutout. The engaging member  120  is fixed inside the hosel hole  122 . As a result, the engaging recess part R 1  is formed inside (on the inner surface of) the hosel hole  122 . 
     In the engaging member  120 , a plurality of engaging recess parts R 1  are provided. As well shown in  FIG. 22 , the plurality of engaging recess parts R 1  are arranged at equal intervals in the circumferential direction. The engaging recess parts R 1  are arranged at intervals of a predetermined angle in the circumferential direction. In the present embodiment, four engaging recess parts R 1  are provided. The engaging recess parts R 1  are arranged at 90-degree intervals in the circumferential direction. The plurality of (four) engaging recess parts R 1  have the same shape. The plurality of engaging recess parts R 1  are varied only in their circumferential-direction positions. 
     As shown in  FIG. 14 , the engaging member  120  is fixed to (a lower part of) the hosel hole  122 . The engaging member  120  is located on a lower side relative to the hosel end surface  140 . The engaging member  120  is located on a lower side relative to the circumferential surface  122   a  of the hosel hole  122 . Fixation of the engaging member  120  can be attained by adhesion, welding, etc. 
     In the connected state, the lower part  134  of the sleeve  108  is inserted to the engaging member  120  ( FIG. 14 ). The inner surface  120   b  of the engaging member  120  is brought into contact with the circumferential surface  135  of the sleeve  108 . The engaging member  120  holds the lower part  134 . 
     Furthermore, in the connected state, the engaging projection parts P 1  of the sleeve  108  are engaged with the engaging recess parts R 1  of the engaging member  120 . The engaging projection parts P 1  are engaged with the respective engaging recess parts R 1 . A rotation of the sleeve  108  with respect to the head  104  is regulated by the engagement. 
     As shown in  FIG. 14 , the intermediate member  114  is located between the engaging member  120  and the flange  126 . An axial-direction distance between the engaging member  120  and the flange  126  is greater than an axial-direction length of the intermediate member  114 . The intermediate member  114  is not fixed to the hosel hole  122 . The intermediate member  114  can move between the engaging member  120  and the flange  126 . 
     In the connected state shown in  FIG. 14 , an axial force caused by tightening the screw  110  is transmitted to the engaging member  120  through the washer  116  and the intermediate member  114 . The engaging member  120  receives the upward axial force. 
     The intermediate member  114  prevents the screw  110  in the separated state from falling off. In the connected state shown in  FIG. 14 , the screw  110  is tightened. The screw  110  moves toward the lower side with respect to the sleeve  108  as the screw  110  is loosened. When the screw  110  is further loosened, the male screw part  110   a  of the screw  110  reaches the intermediate member  114 . As above mentioned, the inner surface of the intermediate member  114  is a female screw. The female screw conforms to the male screw part  110   a . When the screw  110  is further loosened, the male screw part  110   a  is screw-connected to the intermediate member  114 . When the male screw part  110   a  comes out of the screw hole Ht, the male screw part  110   a  is screw-connected to the intermediate member  114 . Even when the male screw part  110   a  is come out of the screw hole Ht and the shaft  112  with the sleeve is detached from the head  104 , the screw  110  which is screw-connected to the intermediate member  114  does not fall off from the head  104 . Since the screw  110  is held by the head  104 , re-connection can be performed smoothly. In addition, the loss of the screw  110  is prevented. 
     [Details of the Engaging Projection Parts P 1  and the Engaging Recess Parts R 1 ] 
     In the above-described first and second embodiments, regulation of falling off (axial-direction movement) of the sleeve with respect to the head is attained by connection between the sleeve and the screw. Regulation of rotation of the sleeve with respect to the head is attained by the engagement between the engaging projection parts P 1  and the respective engaging recess parts R 1 . 
     Hereinafter, the engaging projection parts P 1  and the engaging recess parts R 1  in these embodiments are explained in detail. 
     [Engaging Projection Parts P 1  of the First Embodiment] 
     As shown in  FIG. 8 , in the first embodiment, each of the engaging projection parts P 1  has a first side surface P 11 , a second side surface P 12 , and an outer surface P 13 . The engaging projection part P 1  further has a lower edge P 14 . 
     The first side surface P 11  is a side surface on one side of the engaging projection part P 1 . The second side surface P 12  is a side surface on the other side of the engaging projection part P 1 . 
     A rotating force (relative rotating force) acts between the sleeve  8  and the hosel hole  22  in hitting. A hitting point is located apart from the axis line of the shaft. Therefore, a force which the face receives from a ball at the hitting point produces a rotation moment about the axis line of the shaft. The rotation moment produces the rotating force. 
     The rotating force acts between the engaging projection part P 1  and the corresponding engaging recess part R 1 . Of the two side surfaces in the engaging projection part P 1 , the rotating force acts on the first side surface P 11 . The first side surface P 11  make a greater contribution to the regulation of the rotation as compared with the second side surface P 12 . 
     Thus, the first side surface P 11  is a side surface located on a side which receives the rotating force caused by hitting. The second side surface P 12  is a side surface located on an opposite side to the first side surface P 11 . In a specific engaging projection part P 1 , the first side surface P 11  is a side surface located on an opposite side to the rotating direction of the head (see  FIG. 11 ). 
     The head  4  is right-handed. For this reason, when the head  4  is viewed from the upper side (grip side), the head  4  is rotated in a clockwise direction with respect to the sleeve  8 . As a result, when the sleeve  8  is viewed from the upper side (see  FIG. 11 ), in a specific engaging projection part P 1 , the first side surface P 11  is located on a counter-clockwise side with respect to the second side surface P 12 . In  FIG. 9 , the sleeve  8  is viewed from the lower side. For this reason, the first side surface P 11  is located on the clockwise side with respect to the second side surface P 12 . 
     As shown in  FIG. 8 , the first side surface P 11  is inclined so as to go toward a middle side of the engaging projection part P 1  as approaching to the tip end of the sleeve  8 . The first side surface P 11  is inclined so as to go toward the second side surface P 12  as approaching to the tip end of the sleeve  8 . 
     As shown in  FIG. 8 , the second side surface P 12  is inclined so as to go toward the middle side of the engaging projection part P 1  as approaching to the tip end of the sleeve  8 . The second side surface P 12  is inclined so as to go toward the first side surface P 11  as approaching to the tip end of the sleeve  8 . 
     In light of easy explanation, directions of inclinations (a plus direction and a minus direction) are defined. In the first side surface P 11  and a first opposed surface R 11 , an inclination by which a reaction force caused by the rotating force acts in an engagement releasing direction is defined as a plus-direction inclination. An inclination in an opposite direction to the plus-direction inclination is defined as a minus-direction inclination. In the first side surface P 11  and the first opposed surface R 11 , an inclination by which the reaction force caused by the rotating force acts in an engaging direction is the minus-direction inclination. 
     In the present application, the “engagement releasing direction” means a direction in which the engaging projection part P 1  is extracted from the engaging recess part R 1 , and the “engaging direction” in the present application means a direction in which the engaging projection part P 1  is inserted to (engaged with) the engaging recess part R 1 . 
     In a right-handed golf club as in the present embodiment, as viewed from the upper side (grip side), an inclination inclined so as to go toward the clockwise direction as approaching to the tip end of the sleeve  8  is the plus-direction inclination. As viewed from the upper side, an inclination inclined so as to go toward the counter-clockwise direction as approaching to the tip end of the sleeve  8  is the minus-direction inclination. In a left-handed golf club, as viewed from the upper side, an inclination inclined so as to go toward the counter-clockwise direction as approaching to the tip end of the sleeve  8  is the plus-direction inclination. As viewed from the upper side, an inclination inclined so as to go toward the clockwise direction as approaching to the tip end of the sleeve  8  is the minus-direction inclination. 
     As shown in  FIG. 8 , the first side surface P 11  of the sleeve  8  is inclined in the plus direction. The second side surface P 12  of the sleeve  8  is inclined in the minus direction. 
     A distance between the first side surface P 11  and the second side surface P 12  is decreased toward the tip end of the sleeve  8 . By the structure, a tapered projection part TP 1  is formed on the engaging projection part P 1 . 
     As shown in  FIG. 8  and  FIG. 9 , the outer surface P 13  extends between the first side surface P 11  and the second side surface P 12 . As shown in  FIG. 9 , the outer surface P 13  is a circumferential surface. As shown in  FIG. 8 , the outer surface P 13  has an outer inclination surface K 13  inclined so as to go toward a radial-direction inner side as approaching to the tip end of the sleeve  8 . In the present embodiment, the whole outer surface P 13  is the outer inclination surface K 13 . The outer surface P 13  is a conical projection surface. At the lower edge P 14 , a height of the engaging projection part P 1  is zero. 
     [Engaging Recess Parts R 1  of the First Embodiment] 
     In the first embodiment, each of the engaging recess parts R 1  has the first opposed surface R 11 , a second opposed surface R 12 , and an inner surface R 13 . The engaging recess part R 1  further has a lower edge R 14  (see  FIG. 4 ,  FIG. 5 , and  FIG. 6 ). 
     The first opposed surface R 11  is a side surface of one side of the engaging recess part R 1 . The second opposed surface R 12  is a side surface on the other side of the engaging recess part R 1 . 
     In the connected state, the first opposed surface R 11  is a surface opposed to the first side surface P 11 . The first opposed surface R 11  is brought into contact with the first side surface P 11 . The contact may be surface-contact, may be line-contact, or may be point-contact. 
     In the connected state, the second opposed surface R 12  is a surface opposed to the second side surface P 12 . The second opposed surface R 12  is brought into contact with the second side surface P 12 . The contact may be surface-contact, may be line-contact, or may be point-contact. 
     The above-mentioned rotating force is transmitted to the first side surface P 11  from the first opposed surface R 11 . The first side surface P 11  receives the rotating force. The rotating force is offset between the first side surface P 11  and the first opposed surface R 11 . The rotation of the sleeve  8  is prevented by the engagement between the first opposed surface R 11  and the first side surface P 11 . 
     Thus, of the two side surfaces P 11  and P 12 , the first side surface P 11  is located on a side which receives the rotating force caused by hitting. The first opposed surface R 11  is opposed to the first side surface P 11 . 
     The head  4  is right-handed. For this reason, when the head  4  is viewed from the upper side (grip side), the head  4  is rotated in the clockwise direction with respect to the sleeve  8 . As a result, when the hosel hole  22  is viewed from the upper side (see  FIG. 5 ), in a specific engaging recess part R 1 , the first opposed surface R 11  is located on the counter-clockwise side with respect to the second opposed surface R 12 . 
     As shown in  FIG. 6 , the first opposed surface R 11  is inclined so as to go toward a middle side of the engaging recess part R 1  as approaching to the tip end of the sleeve  8 . The first opposed surface R 11  is inclined so as to go toward the second opposed surface R 12  as approaching to the tip end of the sleeve  8 . 
     As shown in  FIG. 6 , the second opposed surface R 12  is inclined so as to go toward the middle side of the engaging recess part R 1  as approaching to the tip end of the sleeve  8 . The second opposed surface R 12  is inclined so as to go toward the first opposed surface R 11  as approaching to the tip end of the sleeve  8 . The first opposed surface R 11  of the sleeve  8  is inclined in the plus direction. The second opposed surface R 12  of the sleeve  8  is inclined in the minus direction. 
     A distance between the first opposed surface R 11  and the second opposed surface R 12  is decreased toward the tip end of the sleeve  8 . In other words, the distance between the first opposed surface R 11  and the second opposed surface R 12  is decreased as going to the lower side. By this structure, a tapered recess part TR 1  is formed on the engaging recess part R 1 . 
     In the connected state, the inner surface R 13  is a surface opposed to the outer surface P 13  (see  FIG. 3 ). The inner surface R 13  is brought into contact with the outer surface P 13 . The contact may be surface-contact, may be line-contact, or may be point-contact. In the embodiment of  FIG. 3 , the contact between the inner surface R 13  and the outer surface P 13  is surface-contact. 
     As shown in  FIG. 4 ,  FIG. 5 , and  FIG. 6 , the inner surface R 13  extends between the first opposed surface R 11  and the second opposed surface R 12 . As shown in  FIG. 5 , the inner surface R 13  is a circumferential surface. As shown in  FIG. 3 , the inner surface R 13  has an inner inclination surface J 13  inclined so as to go toward the radial-direction inner side as approaching to the tip end of the sleeve  8 . The inner inclination surface J 13  is inclined so as to go toward the radial-direction inner side as going to the lower side. In the present embodiment, the whole inner surface R 13  is the inner inclination surface J 13 . The inner surface R 13  is a conical recess surface. At the lower edge R 14 , a depth of the engaging recess part R 1  is zero. 
     [Engaging Projection Parts P 1  of the Second Embodiment] 
     In the second embodiment, although positions of the engaging projection parts P 1  and the engaging recess parts R 1  are different from those of the first embodiment, the shapes and functions of the engaging recess parts R 1  and the engaging projection parts P 1  are the same as those of the first embodiment. 
     As shown in  FIG. 17 , in the second embodiment, each of the engaging projection parts P 1  has a first side surface P 11 , a second side surface P 12 , and an outer surface P 13 . The engaging projection part P 1  further has a lower edge P 14 . 
     The first side surface P 11  is a side surface on one side of the engaging projection part P 1 . The second side surface P 12  is a side surface on the other side of the engaging projection part P 1 . 
     The first side surface P 11  is located on a side which receives the rotating force caused by hitting. The second side surface P 12  is located on the opposite side to the first side surface P 11 . 
     As shown in  FIG. 16  and  FIG. 17 , the first side surface P 11  is inclined so as to go toward the middle side of the engaging projection part P 1  as approaching to the tip end of the sleeve  108 . The first side surface P 11  is inclined so as to go toward the second side surface P 12  as approaching to the tip end of the sleeve  108 . 
     The second side surface P 12  is inclined so as to go toward the middle side of the engaging projection part P 1  as approaching to the tip end of the sleeve  108 . The second side surface P 12  is inclined so as to go toward the first side surface P 11  as approaching to the tip end of the sleeve  108 . 
     The first side surface P 11  of the sleeve  108  is inclined in the plus direction. The second side surface P 12  of the sleeve  108  is inclined in the minus direction. 
     A distance between the first side surface P 11  and the second side surface P 12  is decreased toward the tip end of the sleeve  108 . A tapered projection part TP 1  is formed on the engaging projection part P 1  by this structure. In the present embodiment, the whole engaging projection part P 1  is the tapered projection part TP 1 . 
     The outer surface P 13  extends between the first side surface P 11  and the second side surface P 12 . As shown in  FIG. 18 , the outer surface P 13  is a circumferential surface. As shown in  FIG. 19 , the outer surface P 13  has an outer inclination surface K 13  inclined so as to go toward the radial-direction inner side as approaching to the tip end of the sleeve  108 . In the present embodiment, the whole outer surface P 13  is the outer inclination surface K 13 . The outer surface P 13  is a conical projection surface. A height of the engaging projection part P 1  at the lower edge P 14  is not zero. 
     [The Engaging Recess Parts R 1  of the Second Embodiment] 
     In the second embodiment, the engaging recess parts R 1  are formed by forming recess parts on a member (the engaging member  120 ) that is separately formed from a head body, and fixing the member to the head body. The engaging recess parts R 1  are formed inside the hosel hole. The engaging recess parts R 1  are formed below the hosel end surface. 
     As shown in  FIG. 21  and  FIG. 22 , in the second embodiment, each of the engaging recess parts R 1  has a first opposed surface R 11  and a second opposed surface R 12 . The engaging recess part R 1  further has a lower edge (bottom surface) R 14 . 
     The first opposed surface R 11  is a side surface on one side of the engaging recess part R 1 . The second opposed surface R 12  is a side surface on the other side of the engaging recess part R 1 . 
     In the connected state, the first opposed surface R 11  is a surface opposed to the first side surface P 11 . The first opposed surface R 11  is brought into contact with the first side surface P 11 . The contact may be surface-contact, may be line-contact, or may be point-contact. 
     In the connected state, the second opposed surface R 12  is a surface opposed to the second side surface P 12 . The second opposed surface R 12  is brought into contact with the second side surface P 12 . The contact may be surface-contact, may be line-contact, or may be point-contact. 
     The above-mentioned rotating force is transmitted to the first side surface P 11  from the first opposed surface R 11 . The first side surface P 11  receives the rotating force. The rotating force is offset between the first side surface P 11  and the first opposed surface R 11 . The rotation of the sleeve  108  is prevented by the engagement between the first opposed surface R 11  and the first side surface P 11 . 
     As shown in  FIG. 21 , the first opposed surface R 11  is inclined so as to go toward the middle side of the engaging recess part R 1  as approaching to the tip end of the sleeve  108 . The first opposed surface R 11  is inclined so as to go toward the second opposed surface R 12  as approaching to the tip end of the sleeve  108 . 
     As shown in  FIG. 21 , the second opposed surface R 12  is inclined so as to go toward the middle side of the engaging recess part R 1  as approaching to the tip end of the sleeve  108 . The second opposed surface R 12  is inclined so as to go toward the first opposed surface R 11  as approaching to the tip end of the sleeve  108 . 
     The first opposed surface R 11  of the sleeve  108  is inclined in the plus direction. The second opposed surface R 12  of the sleeve  108  is inclined in the minus direction. 
     The distance between the first opposed surface R 11  and the second opposed surface R 12  is decreased toward the tip end of the sleeve  108 . A tapered recess part TR 1  is formed on the engaging recess part R 1  by this structure. At the lower edge R 14 , the engaging recess part R 1  includes a bottom surface having a width in the radial direction. 
     In the second embodiment, inner surfaces R 13  are not provided. However, even when an engaging member  120  which includes cutout-shaped engaging recess parts R 1  as shown in  FIG. 21  is used, it is possible to form inner surfaces R 13 . For example, of the inner surface of the hosel hole  122  located on a position where the engaging member  120  is fixed, portions which are located between the first opposed surfaces R 11  and the respective second opposed surfaces R 12  can be used as the inner surfaces R 13 . 
       FIG. 23  is a side view of a sleeve  208  which is a modification example. The sleeve  208  is the same as the above-described sleeve  8  except for an angle of the first side surfaces P 11 .  FIG. 24  is a sectional view of a head body  218  suited to the sleeve  208 . The head body  218  is the same as the above-described head body  18  except for an angle of the first opposed surfaces R 11 . 
     A two-dot chain line in  FIG. 23  shows an extending direction of each first side surface P 11 . In the sleeve  208 , the first side surface P 11  extends along the axial direction. The first side surface P 11  is parallel to the axial direction. The first side surface P 11  is not inclined in the plus direction. The first side surface P 11  is not inclined in the minus direction. 
     A two-dot chain line in  FIG. 24  shows an extending direction of each first opposed surface R 11 . In the head body  218 , the first opposed surface R 11  extends along the axial direction. The first opposed surface R 11  is parallel to the axial direction. The first opposed surface R 11  is not inclined in the plus direction. The first opposed surface R 11  is not inclined in the minus direction. 
     [The Effect of the Engaging Projection Part P 1  and the Engaging Recess Part R 1 ] 
     The engaging projection part P 1  and the engaging recess part R 1  in the above-described embodiments can fulfill the following advantageous effects. 
     The rotation of a sleeve with respect to a hosel hole is regulated by the engagement between the engaging recess part R 1  and the engaging projection part P 1 . 
     The engaging projection part P 1  has the tapered projection part TP 1 . Therefore, the engaging projection part P 1  can be entered into the engaging recess part R 1  easily. As a result, detaching/attaching of the sleeve (shaft) from/to the head becomes easy, and thus the connected state can be securely attained. 
     The engaging recess part R 1  has the tapered recess part TR 1 . Therefore, the engaging recess part R 1  can accept the engaging projection part P 1  easily. As a result, detaching/attaching of the sleeve (shaft) from/to the head becomes easy, and thus the connected state can be securely attained. 
     [Rotation-Direction Fixing Effect  1 ] 
     By inserting the tapered projection part TP 1  to the engaging recess part R 1 , a slight gap (also referred to as a rotation-direction gap) between the first side surface P 11  and the first opposed surface R 11  can be eliminated. Therefore, a very slight relative rotation between the sleeve and the hosel hole is prevented. In the present application, this effect is also referred to as a rotation-direction fixing effect. 
     [Rotation-Direction Fixing Effect  2 ] 
     By inserting the engaging projection part P 1  to the tapered recess part TR 1 , the rotation-direction gap can be eliminated. Therefore, a very slight relative rotation between the sleeve and the hosel hole is prevented. 
     [Rotation-Direction Fixing Effect  3 ] 
     By inserting the tapered projection part TP 1  to the tapered recess part TR 1 , the synergistic effect of the rotation-direction fixing effect  1  and the rotation-direction fixing effect  2  is fulfilled. For this reason, the rotation-direction gap is further securely eliminated. 
     [Radial-Direction Fixing Effect  1 ] 
     As described above, the outer inclination surface K 13  is formed on the outer surface P 13  of the engaging projection part P 1 . By inserting the engaging projection part P 1  which has the outer inclination surface K 13  to the engaging recess part R 1 , it becomes possible to eliminate a slight gap (also referred to as a radial-direction gap) between the outer surface P 13  and the inner surface R 13 . Therefore, a slight play in the radial direction between the sleeve and the hosel hole is prevented. In the present application, this effect is also referred to as a radial-direction fixing effect. 
     [Radial-Direction Fixing Effect  2 ] 
     As described above, the inner inclination surface J 13  is formed on the inner surface R 13  of the engaging recess part R 1 . By inserting the engaging projection part P 1  to the engaging recess part R 1  which has the inner inclination surface J 13 , it becomes possible to eliminate the radial-direction gap. Therefore, the slight play in the radial direction between the sleeve and the hosel hole is prevented. 
     [Radial-Direction Fixing Effect  3 ] 
     The synergistic effect of the radial-direction fixing effect  1  and the radial-direction fixing effect  2  is fulfilled by inserting the engaging projection part P 1  which has the outer inclination surface K 13  to the engaging recess part R 1  which has the inner inclination surface J 13 . The radial-direction gap is further securely eliminated by the synergistic effect. 
       FIG. 25  is a schematic view showing an engaging projection part P 1  and an engaging recess part R 1  according to a modification example. 
     A double-pointed arrow WP 1  in  FIG. 25  shows a maximum width of a tapered projection part TP 1 . A double-pointed arrow WR 1  in  FIG. 25  shows an opening width of the engaging recess part R 1 . The opening width WR 1  is the maximum width of a portion, in the engaging recess part R 1 , which can be engaged with the engaging projection part P 1 . The opening width WR 1  is a width of the upper end of a portion, in the engaging recess part R 1 , which can be engaged with the engaging projection part P 1 . 
     In light of the rotation-direction fixing effect, the maximum width WP 1  is preferably equal to or greater than the opening width WR 1 , and more preferably greater than the opening width WR 1 . By this structure, the engaging projection part P 1  is surely fitted to the engaging recess part R 1  thereby to securely eliminate the rotation-direction gap. 
     In light of the rotation-direction fixing effect, a difference [WP 1 −WR 1 ] is preferably equal to or greater than 0.05 mm, and more preferably equal to or greater than 0.1 mm. If the difference [WP 1 −WR 1 ] is excessively great, the gap between the hosel end surface and the step surface of the sleeve becomes large, and appearance can deteriorate. In this respect, the difference [WP 1 −WR 1 ] is preferably equal to or less than 4.0 mm, and more preferably equal to or less than 2.0 mm. 
     A double-pointed arrow DP 1  in  FIG. 25  shows an insertable length of the engaging projection part P 1 . The length DP 1  is an inserted length of the engaging projection part P 1  in a state where the engaging projection part P 1  is most deeply inserted to the engaging recess part R 1 . A double-pointed arrow DR 1  in  FIG. 25  shows an axial-direction depth of the engaging recess part R 1 . 
     In light of the rotation-direction fixing effect, the depth DR 1  is preferably greater than the length DP 1 . This structure suppresses deterioration of a contact pressure between the first side surface P 11  and the first opposed surface R 11 , which could be caused by abutment between the lower edge P 14  and the lower edge R 14 . For this reason, the engaging projection part P 1  is surely fitted to the engaging recess part R 1  thereby to securely eliminate the rotation-direction gap. 
     In light of eliminating the rotation-direction gap, the following structure (a) is preferable. 
     (a) In the connected state, a gap is present between the lower edge P 14  of the engaging projection part P 1  and the lower edge R 14  of the engaging recess part R 1 . 
     By the structure (a), the engaging projection part P 1  is surely fitted to the engaging recess part R 1  thereby to securely eliminate the rotation-direction gap. 
     In light of eliminating the rotation-direction gap and the radial-direction gap, the following structure (b) or structure (c) may be adopted. 
     (b) In the connected state, the contact between the engaging projection part P 1  and the engaging recess part R 1  is limited to: a contact between the first side surface P 11  and the first opposed surface R 11 ; a contact between the second side surface P 12  and the second opposed surface R 12 ; and a contact between the outer surface P 13  and the inner surface R 13 . 
     (c) In the connected state, the contact between the engaging projection part P 1  and the engaging recess part R 1  is limited to: a contact between the tapered projection part TP 1  and the tapered recess part TR 1 ; and a contact between the outer inclination surface K 13  and the inner inclination surface J 13 . 
     In light of eliminating the rotation-direction gap, the following structure (d) is preferable. 
     (d) In the connected state, the axial force of the screw creates the contact pressure between the first side surface P 11  and the first opposed surface R 11 . 
     In light of eliminating the radial-direction gap, the following structure (e) is preferable. 
     (e) In the connected state, the axial force of the screw creates a contact pressure between the outer inclination surface K 13  and the inner inclination surface J 13 . 
     The inventor of the present application has found that a conventional club including a sleeve arouses a strange feeling in hitting. The strange feeling is a feeling (feeling of a twist) as if a twist occurs between the sleeve and the hosel hole. The inventor has found that the strange feeling results from the slight rotation-direction gap and a slight radial-direction gap. By the above-mentioned embodiments, the strange feeling in hitting can be eliminated. 
     [Axial-Direction Deviation] 
     The inventor has found that there also is another factor which produces the strange feeling other than the rotation-direction gap and the radial-direction gap. 
     When the first side surface P 11  is an inclination surface having an angle of the plus direction, the reaction force transmitted from the inclination surface acts in the engagement releasing direction. For this reason, the engaging projection part P 1  can be moved toward an axial-direction upper side with respect to the engaging recess part R 1 . This movement is also referred to as an axial-direction deviation. The axial-direction deviation makes the engagement between the engaging recess part R 1  and the engaging projection part P 1  insecure. 
     In light of preventing the axial-direction deviation, the following structure (f), (g), or (h) is preferable. 
     (f) The first side surface P 11  extends along the axial direction (see  FIG. 23 ). 
     (g) The first opposed surface R 11  extends along the axial direction (see  FIG. 24 ). 
     (h) The first side surface P 11  extends along the axial direction, and the first opposed surface R 11  which abuts on the first side surface P 11  extends along the axial direction (see  FIG. 26( a )  described later). 
     A surface which extends along the axial direction does not produce a force acting in the engagement releasing direction. For this reason, the axial-direction deviation can be prevented. 
     The structure (h) is effective. In the structure (h), the first side surface P 11  and the first opposed surface R 11  both extending along the axial direction can be brought into surface-contact with each other. Since the surfaces extending along the axial direction are surfaces perpendicular to the rotation direction, the surfaces can surely receive a force in the rotation direction. Since a force acting in the engagement releasing direction does not arise, the axial-direction deviation is prevented. 
     The structure (f) or (g) can also have a sufficient effect. For example, in the structure (f), a case where the first opposed surface R 11  abutting on the first side surface P 11  is inclined in the plus direction is considered. In this case, the first opposed surface R 11  can produce a force in the engagement releasing direction. However, in this case, the contact between the first side surface P 11  and the first opposed surface R 11  is point-contact or line-contact, not surface-contact. For this reason, the contact pressure increases to increase frictional force. As a result, sliding between the first side surface P 11  and the first opposed surface R 11  is suppressed, and the axial-direction deviation is suppressed. 
     Thus, in light of preventing the axial-direction deviation, the following structure (i) is preferable. 
     (i) In the connected state, the contact between the first side surface P 11  and the first opposed surface R 11  is point-contact or line-contact. 
     In light of attaining the structure (i), the following structure (j) may be adopted. 
     (j) In the connected state, the first side surface P 11  and the first opposed surface R 11  are not parallel to each other. 
     In light of preventing the axial-direction deviation, the following structure (k), (m), or (n) is also preferable. 
     (k) The first side surface P 11  is inclined in the minus direction. 
     (m) The first opposed surface R 11  is inclined in the minus direction. 
     (n) The first side surface P 11  is inclined in the minus direction, and the first opposed surface R 11  which abuts on the first side surface P 11  is inclined in the minus direction. 
     The rotating force acts in the engaging direction by the inclination in the minus direction. Therefore, the axial-direction deviation is prevented. 
       FIG. 26( a ) ,  FIG. 26( b ) ,  FIG. 26( c ) ,  FIG. 27( a ) , and  FIG. 27( b )  are schematic views showing an engaging projection part P 1  and an engaging recess part R 1  according to each modification example. 
     In the embodiment of  FIG. 26( a ) , the first side surface P 11  extends along the axial direction. The first opposed surface R 11  also extends along the axial direction. The second side surface P 12  is inclined in the minus direction. The second opposed surface R 12  is inclined in the minus direction. 
     Since the first side surface P 11  and the first opposed surface R 11  extend along the axial direction, the axial-direction deviation does not arise if the rotating force acts. The rotating force which acts perpendicularly to the axial direction can be surely received by the abutting between the surfaces extending along the axial direction. Therefore, the rotation-direction fixing effect is enhanced. 
     In the embodiment of  FIG. 26( b ) , the first side surface P 11  extends along the axial direction. The first opposed surface R 11  is inclined in the minus direction. The second side surface P 12  is inclined in the minus direction. The second opposed surface R 12  is inclined in the minus direction. 
     The first side surface P 11  and the first opposed surface R 11  are not parallel to each other. In the connected state, the contact between the first side surface P 11  and the first opposed surface R 11  is point-contact or line-contact. In the present embodiment, the axial-direction deviation is prevented. 
     In the embodiment of  FIG. 26( c ) , the first opposed surface R 11  extends along the axial direction. The first side surface P 11  is inclined in the plus direction. The second side surface P 12  is inclined in the minus direction. The second opposed surface R 12  is inclined in the minus direction. 
     The first side surface P 11  and the first opposed surface R 11  are not parallel to each other. In the connected state, the contact between the first side surface P 11  and the first opposed surface R 11  is point-contact or line-contact. In the present embodiment, the axial-direction deviation is prevented. Although the first side surface P 11  is inclined in the plus direction, an increased contact pressure makes frictional force large. For this reason, sliding between the first side surface P 11  and the first opposed surface R 11  can hardly occur. In the present embodiment, the axial-direction deviation is prevented. 
     In the embodiment of  FIG. 27( a ) , the first side surface P 11  is inclined in the minus direction. The first opposed surface R 11  is inclined in the minus direction. The second side surface P 12  is inclined in the minus direction. The second opposed surface R 12  is inclined in the minus direction. In the present embodiment, the axial-direction deviation is prevented. 
     The inclination angle of the first side surface P 11  is smaller than the inclination angle of the second side surface P 12 . Therefore, the engaging projection part P 1  is the tapered projection part TP 1  also in the present embodiment. The inclination angle of the first opposed surface R 11  is smaller than the inclination angle of the second opposed surface R 12 . Therefore, the engaging recess part R 1  is the tapered recess part TR 1  also in the present embodiment. In the present embodiment, when the engaging projection part P 1  is inserted to the engaging recess part R 1 , the sleeve is (slightly) rotated. 
     As shown in the embodiment of  FIG. 27( a ) , even when the first side surface P 11  and the second side surface P 12  are inclined in the same direction, a tapered projection part TP 1  can be formed. Even when the first opposed surface R 11  and the second opposed surface R 12  are inclined in the same direction, a tapered recess part TR 1  can be formed. 
     In the embodiment of  FIG. 27( b ) , the first side surface P 11  extends along the axial direction. The first opposed surface R 11  is inclined in the plus direction. The second side surface P 12  is inclined in the minus direction. The second opposed surface R 12  is inclined in the minus direction. In the connected state, the contact between the first side surface P 11  and the first opposed surface R 11  is point-contact or line-contact. In the present embodiment, the axial-direction deviation is prevented. 
     In the present embodiment, the first opposed surface R 11  is inclined in the plus direction. However, because of the point-contact or line-contact, the contact pressure is increased and thus the frictional force is large. For this reason, sliding between the first side surface P 11  and the first opposed surface R 11  can hardly occur. In the present embodiment, the axial-direction deviation is prevented. 
     The number of the engaging projection parts P 1  may be one, and may be two or more. Even when the number is one, the above-described effects such as the rotation-direction fixing effect are fulfilled. When a plurality of engaging projection parts P 1  are provided, the engaging projection parts  21  are preferably arranged at equal intervals in the circumferential direction. The number of the engaging recess parts R 1  is preferably equal to the number of the engaging projection parts P 1 . 
     Examples of the material of the engaging projection part P 1  include a metal and a resin. Examples of the metal include a titanium alloy, stainless steel, an aluminum alloy, and a magnesium alloy. In light of strength and lightweight properties, the aluminum alloy and the titanium alloy are 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 sleeve having the engaging projection part P 1  can be manufactured by forging, casting, pressing, NC processing, and a combination thereof. 
     Examples of the material of a portion in which the engaging recess part R 1  is formed include a metal and a resin. Examples of the metal include a titanium alloy, stainless steel, an aluminum alloy, and a magnesium alloy. In light of strength and lightweight properties, the aluminum alloy and the titanium alloy are 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 head having the engaging recess part R 1  can be manufactured by forging, casting, pressing, NC processing, and a combination thereof. By using an engaging member  120  which is a separated member from a head body as in the second embodiment, processing of the engaging recess part R 1  is made easy. 
     As shown in the above disclosure, advantages of the embodiments are clear. 
     The golf clubs described above can be applied to all types of golf clubs such as an iron type golf club, a hybrid type golf club, and a wood type golf club. 
     The above description is merely illustrative example, and various modifications can be made without departing from the principles of the present disclosure.