Golf Club

Abstract

A golf club 2 is provided with a head 4, a shaft 6, a grip body 8a, and an extending member 8b. The extending member 8b is detachably mounted to a back end of the grip body 8a. A length of a grip holding surface 8m can be adjusted by mounting and dismounting the extending member 8b. Preferably, the grip body 8a has a hard base body h1. Preferably, the extending member 8b has a hard connector h2. Preferably, the extending member 8b can be mounted to the back end of the grip body 8a by connecting the hard base body h1 and the hard connector h2 to each other. The number of the extending member 8b may be 1 or equal to or greater than 2. Preferably, the extending members are detachably mounted to each other.

Description

[0001] The application claims priority on Patent Application No. 2009-298971 filed in JAPAN on Dec. 28, 2009, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a golf club capable of adjusting a club length.

[0004] 2. Description of the Related Art

[0005] An optimal length of a golf club is different at every golf player. Generally, the golf player selects and purchases a golf club having a length suitable for the golf player. However, options of a club length in a commercial item are limited. It is useful to easily adjust the club length.

[0006] The club length can be adjusted by shaft replacement. In a normal golf club, a head and a shaft are bonded to each other by using an adhesive. For this reason, the shaft replacement is not easy in the normal golf club. Therefore, the adjustment of the club length is not also easy.

[0007] Japanese Patent Application Laid-Open (JP-A) No. 2006-42951 and Japanese Patent Application National Publication (Laid-Open) No. 2005-533626 disclose golf clubs in which a head and a shaft are connected to each other by screw connection. In the golf clubs, the mounting and dismounting of the shaft are easy. A length of the golf club can be changed by exchanging the shaft to a shaft having a different length.

[0008] JP-A No. 2008-29691 discloses a golf club in which a collar member is attached to an outer circumference of a tip part of a shaft. The collar member can adjust a relative position of the shaft with a shaft hole in an axial direction. In the golf club, a club length can be adjusted by changing an inserting length of the shaft to a head.

[0009] JP-A No. 2005-160689 discloses a golf putter in which a length of a shaft inserted into a grip can be adjusted. In the golf club, a club length can be adjusted by changing an inserting length of the shaft to the grip.

[0010] Japanese Utility Model Application Publication (JP-Y) No. 3052104 discloses a hitting club having a shaft overlapping part in which two shafts having different apertures are overlapped. union coupling is used for the hitting club. In the golf club, a slide mechanism can adjust a length of the shaft itself.

SUMMARY OF THE INVENTION

[0011] When the shaft is exchanged to the other shaft having a different length, a new shaft for the exchange is required. Generally, a shaft is expensive. The use of the shaft for the exchange causes expense increase. When the inserting length of the shaft to the head is changed, a swing weight (swing balance) may be fluctuated, or shaft strength may be insufficient. When the length of the shaft inserted into the grip is adjusted, the swing weight is apt to be fluctuated. Grip rigidity of a portion into which the shaft is not inserted is apt to be insufficient. The insufficient rigidity may destabilize a swing and a club behavior.

[0012] It is an object of the present invention to provide a golf club facilitating adjust of a club length and capable of suppressing disadvantages caused by the adjustment of the club length.

[0013] A golf club according to the present invention is provided with a head, a shaft, a grip body, and an extending member. The extending member is detachably mounted to a back end of the grip body. A length of a holding surface of a gap can be adjusted by mounting and dismounting the extending member.

[0014] A preferable golf club is further provided with a hard base body. Preferably, the extending member has a hard connector. Preferably, the extending member can be mounted to the back end of the grip body by connecting the hard base body and the hard connector to each other.

[0015] Preferably, the extending member has a hard connector. Preferably, the grip body has a cavity part having an undercut structure. Preferably, the cavity part is made of rubber. Preferably, the hard connector can be mounted to the cavity part by using elastic deformation of the rubber. Preferably, due to the undercut structure, the hard connector can be less likely to come off the cavity part.

[0016] Preferably, the hard base body and the shaft are separated from each other. Preferably, rubber exists between the hard base body and the shaft.

[0017] Preferably, the hard base body and the hard connector are separated from each other with the extending member mounted to the grip body. Preferably, rubber exists between the hard base body and the hard connector.

[0018] A preferable golf club is provided with the plurality of extending members. Preferably, the extending members are detachably mounted to each other. Preferably, a length of the grip can be adjusted by connecting number of the extending members.

[0019] Preferably, the hard connectors are separated from each other with the extending members connected to each other. Preferably, rubber exists between the hard connectors.

[0020] Preferably, each of the plurality of extending members has a cavity part having an undercut structure. Preferably, the cavity part is made of rubber. Preferably, the hard connector of the first extending member can be mounted to the cavity part of the second extending member by using elastic deformation of the rubber. Preferably, due to the undercut structure, the second extending member can be less likely to come off the first extending member.

[0021] A preferable golf club is provided with the plurality of extending members having lengths different from each other. Preferably, a length of the grip can be adjusted by selection or combination of the extending members.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a view showing a golf club according to a first embodiment of the present invention;

[0023] FIG. 2 is an enlarged view showing a vicinity of a grip end of the golf club of FIG. 1;

[0024] FIG. 3 is a cross sectional view of FIG. 2;

[0025] FIG. 4 is an exploded view of FIG. 2;

[0026] FIG. 5 is a cross sectional view of FIG. 4;

[0027] FIG. 6 is an enlarged view showing a vicinity of a grip end of a golf club of a second embodiment;

[0028] FIG. 7 is a cross sectional view of FIG. 6;

[0029] FIG. 8 is an exploded view of FIG. 6;

[0030] FIG. 9 is an exploded view of a golf club of a third embodiment;

[0031] FIG. 10 is an enlarged view showing a vicinity of a grip end of a golf club according to a fourth embodiment of the present invention;

[0032] FIG. 11 is a view for explaining a method for measuring an out-of-plane primary attenuation rate;

[0033] FIG. 12 is a view for explaining a method for calculating an out-of-plane primary attenuation rate;

[0034] FIG. 13 is an enlarged view showing a vicinity of a grip end of a golf club of example 2;

[0035] FIG. 14 is a cross sectional view of FIG. 13;

[0036] FIG. 15 is an exploded view of FIG. 13, and is a partial cross sectional view;

[0037] FIG. 16 is a side view independently showing a hard connector used in an embodiment of FIG. 13;

[0038] FIG. 17 is an enlarged view showing a vicinity of a grip end of a golf club of example 4;

[0039] FIG. 18 is a cross sectional view of FIG. 17;

[0040] FIG. 19 is an exploded view of FIG. 17, and is a partial cross sectional view; and

[0041] FIG. 20 is a side view independently showing a hard connector used in an embodiment of FIG. 17.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] The present invention will be described below in detail based on preferred embodiments with reference to the drawings.

[0043] In the present application, an "axial direction" means a direction of a central axial line of a shaft unless particularly described.

[0044] As shown in FIG. 1, a golf club 2 has a golf club head 4, a golf club shaft 6, and a golf club grip 8. The head 4 is mounted to one end part of the shaft 6. The grip 8 is mounted to the other end part of the shaft 6.

[0045] The head 4 is not limited. A wood type head, an iron type head, and a putter head are exemplified as the head 4. The wood type head is illustrated in FIG. 1. The shaft 6 is not limited. A so-called a steel shaft and a so-called carbon shaft are exemplified as the shaft 6.

[0046] FIG. 2 is an enlarged view of a vicinity of a grip end of FIG. 1. Grooves are formed on an external surface (grip holding surface) of the grip 8. However, the description of the grooves is omitted in the drawings of the present application. The grip holding surface is a surface capable of being brought into contact with a golf player's hand when using the golf club 2. A side surface of the grip 8 is the grip holding surface. In the present application, the grip holding surface is also merely referred to as a holding surface.

[0047] The shaft 6 is cylindrical although not shown in the drawings. The grip 8 is approximately cylindrical although not shown in the drawings. A holding surface 8m of the grip 8 is a curved surface having an approximately circumferential surface shape.

[0048] The grip 8 may have a so-called back line. In this case, after the shaft 6 is inserted into the grip 8, a sectional shape of the holding surface 8m of the grip 8 is not a true circle. The grip 8 may not have a so-called back line.

[0049] The grip 8 has a grip body 8a and two extending members 8b. The two extending members 8b are mounted to a back end of the grip body 8a.

[0050] The grip body 8a is fixed to a back end part of the shaft 6 by using a double-faced adhesive tape. An adhesion method using the double-faced adhesive tape is the same as that of a normal adhesion method of a grip.

[0051] A first extending member 8b is mounted to the back end of the grip body 8a. A second extending member 8b is mounted to a back end of the first extending member 8b.

[0052] A part of the holding surface 8m of the grip 8 is formed by the grip body 8a. A part of the holding surface 8m is formed by the extending members 8b.

[0053] An external surface 8a1 of the grip body 8a and an external surface 8b1 of the extending member 8b are substantially steplessly connected. The holding surface 8m is formed by the external surface 8a1 and the external surfaces 8b1.

[0054] FIG. 3 is a cross sectional view of FIG. 2; FIG. 4 is an exploded view of FIG. 2; and FIG. 5 is a cross sectional view of FIG. 4. Sectional positions of the cross sectional views of the present application are positions including a shaft axial line.

[0055] As shown in FIGS. 3, 4, and 5, the grip 8 has a connecting member 8c in addition to the grip body 8a and the extending members 8b. In the embodiment, the connecting member 8c is a screw. The connecting member 8c has a head part 8c1 and a screw part 8c2.

[0056] The grip body 8a has a rubber part g1 and a hard base body h1. The rubber part g1 and the hard base body h1 may be separated from each other.

[0057] A material of the rubber part g1 is rubber. The rubber part g1 has a cavity part cv1 (see FIGS. 4 and 5).

[0058] The hard base body h1 is provided inside the rubber part g1. The external surface 8a1 of the grip body 8a is an external surface of the rubber part g1.

[0059] The cavity part cv1 has an inner diameter enlarging part e1 having an inner diameter d2 greater than an opening diameter d1 (see FIG. 5). The cavity part cv1 has an undercut structure. The undercut structure is not limited to the form of FIG. 5.

[0060] The hard base body h1 has a screw hole sc1 (see FIG. 5). A lower part of the hard base body h1 is disposed inside the shaft 6. The hard base body h1 may be bonded to the shaft 6.

[0061] The rubber part g1 and the hard base body h1 may be separable from each other. When the grip body 8a is attached to the shaft 6, the hard base body h1 may be first mounted to the shaft 6, and the rubber part g1 may be then mounted to the shaft 6 with the hard base body h1.

[0062] The first extending member 8b is located between the grip body 8a and the second extending member 8b.

[0063] The first extending member 8b has a rubber part g2 and a hard connector h2.

[0064] A material of the rubber part g2 is rubber. The rubber part g2 has a cavity part cv2.

[0065] The hard connector h2 is provided inside the rubber part g2. The rubber part g2 covers a part of the hard connector h2. The external surface 8b1 of the extending member 8b is an external surface of the rubber part g2.

[0066] The cavity part cv2 has an inner diameter enlarging part e2 having an inner diameter d2 greater than an opening diameter d1 (see FIG. 5). The cavity part cv2 has an undercut structure. The undercut structure is not limited to the form of FIG. 5.

[0067] The hard connector h2 has a screw hole sc2 (see FIG. 5). The hard connector h2 is mounted to the cavity part cv1 described above. The hard connector h2 is fitted into the cavity part cv1 of the grip body 8a.

[0068] The hard connector h2 has a small diameter part h21 and a great diameter part h22 (see FIGS. 3 and 4). The hard connector h2 has an exposed part ex1 (see FIG. 4). The exposed part ex1 is not covered with the rubber part g2. The exposed part ex1 is projected from the rubber part g2.

[0069] An outer diameter of the small diameter part h21 corresponds to the opening diameter d1 of the cavity part cv1. The outer diameter of the small diameter part h21 is equal to the opening diameter d1 of the cavity part cv1, or is equal to or less than the opening diameter d1 of the cavity part cv1.

[0070] An outer diameter of the great diameter part h22 corresponds to the inner diameter d2 of the inner diameter enlarging part e1. The outer diameter of the great diameter part h22 is approximately equal to the inner diameter d2 of the inner diameter enlarging part e1.

[0071] The second extending member 8b is located on a grip back end side of the first extending member 8b. The second extending member 8b is the extending member 8b located on the backmost side.

[0072] The second extending member 8b is the same as the first extending member 8b described above. Therefore, the description of the second extending member 8b is omitted.

[0073] The mounting order of the second extending member 8b and the first extending member 8b can be switched. That is, the second extending member 8b can be mounted to the back end of the grip body 8a, and the first extending member 8b can be mounted to the back end of the second extending member 8b.

[0074] In the second extending member 8b, an outer diameter of a small diameter part h21 corresponds to the opening diameter d1 of the cavity part cv2 of the first extending member 8b. An outer diameter of the small diameter part h21 is approximately equal to the opening diameter d1 of the cavity part cv2, or is equal to or less than the opening diameter d1 of the cavity part cv2.

[0075] In the second extending member 8b, an outer diameter of the great diameter part h22 corresponds to the inner diameter d2 of the inner diameter enlarging part e2 of the first extending member 8b. The outer diameter of the great diameter part h22 is approximately equal to the inner diameter d2 of the inner diameter enlarging part e2.

[0076] As shown in FIG. 3, the hard connector h2 of the extending member 8b (first extending member 8b) is fitted into the cavity part cv1 of the grip body 8a. Furthermore, the hard connector h2 of the second extending member 8b is fitted into the cavity part cv2 of the first extending member 8b.

[0077] Thus, the grip body 8a has the cavity part cv1 having the undercut structure. Each of the extending members 8b has the cavity part cv2 having the undercut structure. The exposed parts ex1 of the hard connectors h2 are fitted into the cavity part cv1 and the cavity part cv2.

[0078] Since the opening diameter d1 is smaller than the outer diameter of the great diameter part h22, the hard connector h2 (exposed part ex1) cannot be fitted into the cavity part cv1 unless the cavity part cv1 is deformed. Since the cavity part cv1 is made of rubber, the cavity part cv1 can be elastically deformed. The hard connector h2 is mounted to the cavity part cv1 by using the elastic deformation of rubber. Due to the undercut structure, the hard connector h2 (exposed part ex1) is less likely to come off the cavity part cv1 in a state where the mounting is completed (a state of FIG. 3). Thus, the hard connector h2 is less likely to come off the cavity part cv1.

[0079] The undercut structure is utilized also for connecting the extending members 8b to each other.

[0080] Since the opening diameter d1 is smaller than the outer diameter of the great diameter part h22, the hard connector h2 (exposed part ex1) of the second extending member 8b cannot be fitted into the cavity part cv2 unless the cavity part cv2 of the first extending member 8b is deformed. Since the cavity part cv2 is made of rubber, the cavity part cv2 can be elastically deformed. The hard connector h2 of the second extending member 8b is mounted to the cavity part cv2 of the first extending member 8b by using the elastic deformation of the rubber. Due to the undercut structure, the hard connector h2 (exposed part ex1) is less likely to come off the cavity part cv2 in a state where the mounting is completed (a state of FIG. 3). Thus, the hard connector h2 is less likely to come off the cavity part cv2.

[0081] In the embodiment, connection by the connecting member 8c is used in addition to the connection of the cavity part cv1 and the hard connector h2, and the connection of the cavity part cv2 and the hard connector h2. As shown in FIG. 3, the connecting member 8c penetrates the extending members 8b to reach the hard base body h1. The connecting member 8c is screwed to the screw holes sc2 of all the extending members 8b. Furthermore, the connecting member 8c is screwed to the screw hole sc1 of the hard base body h1. The hard base body h1 and the hard connectors h2 are connected to each other by the connecting member 8c. The connection is further strengthened by the connecting member 8c.

[0082] The head part 8c1 of the connecting member 8c is housed in the cavity part cv2 of the extending member 8b (second extending member 8b) placed at the backmost end (see FIG. 3). That is, the head part 8c1 is not projected to the outside. The connecting member 8c is not a hindrance in the use of the golf club.

[0083] In the first embodiment, the connection of the hard connector h2 and the cavity part is used in combination with the connection by the connecting member 8c. The combined use ensures the connection. Either the connection of the hard connector h2 and the cavity part or the connection by the connecting member 8c may be used.

[0084] In the first embodiment, the extending members 8b are detachably mounted. When the extending members 8b are removed, the connecting member 8c is first removed, and the hard connectors h2 are then removed from the cavity parts (cv1, cv2) by using the elastic deformation of the rubber. A length Lg (see FIG. 1) of a grip holding part can be adjusted by mounting and dismounting the extending members 8b.

[0085] In the embodiment, the case where the number of the extending members 8b is two is shown. The length Lg of the grip holding part can be changed by changing the number of the extending members 8b. When the number of the extending members 8b is 0, the length Lg can be shortened. The number of the extending members 8b may be 1. The length Lg is measured along the axial direction.

[0086] The number of the extending members 8b may be equal to or greater than 3. Since the connecting structure of the extending members 8b is the same, the number of the extending members 8b to be connected can be optionally selected.

[0087] Preferably, the length of the connecting member 8c is made different according to the number of the extending members 8b to be connected.

[0088] FIG. 6 is an enlarged view showing a vicinity of a grip end of a grip 10 of a second embodiment. FIG. 7 is a cross sectional view of the grip 10 of FIG. 6. FIG. 8 is an exploded view of the grip 10 of FIG. 6.

[0089] The grip 10 has a grip body 10a and two extending members 10b. The two extending members 10b are mounted to a back end of the grip body 10a.

[0090] The grip body 10a is fixed to a back end part of a shaft 6 by using a double-faced adhesive tape. An adhesion method of the double-faced adhesive tape is the same as a normal adhesion method of a grip.

[0091] The first extending member 10b is mounted to the back end of the grip body 10a. The second extending member 10b is mounted to a back end of the first extending member 10b.

[0092] As shown in FIG. 6, a part of a holding surface 10m of the grip 10 is formed by the grip body 10a. A part of the holding surface 10m is formed by the extending members 10b.

[0093] An external surface 10a1 of the grip body 10a and an external surface 10b1 of the extending member 10b are substantially steplessly connected. Furthermore, the external surfaces 10b1 of the extending members 10b are substantially steplessly connected. The holding surface 10m is formed by the external surface 10a1 and the two external surfaces 10b1.

[0094] The grip body 10a has a rubber part g3 and a hard base body h3. A material of the rubber part g3 is rubber.

[0095] The hard base body h3 is provided inside the rubber part g3. The rubber part g3 covers the hard base body h3. The external surface 10a1 of the grip body 10a is an external surface of the rubber part g3.

[0096] As shown in FIGS. 7 and 8, the hard base body h3 has a screw hole sc3. The hard base body h3 has a cylinder part h31 and a bottom face part h32. An inner surface of the cylinder part h31 is the screw hole sc3. The screw hole sc3 is opened upward.

[0097] The hard base body h3 is fixed to the rubber part g3. The fixing method is not limited. For example, the fixing method is adhesion by an adhesive.

[0098] The first extending member 10b is located between the grip body 10a and the second extending member 10b. The first extending member 10b has a rubber part g4 and a hard connector h4. A material of the rubber part g4 is rubber. The rubber part g4 covers an upper part of the hard connector h4.

[0099] The hard connector h4 is provided inside the rubber part g4. The external surface 10b1 of the extending member 10b is an external surface of the rubber part g4.

[0100] The hard connector h4 has a cylindrical part h41 and a columnar part h42 (see FIG. 7). An inner surface of the cylindrical part h41 is a screw hole sc4 (female screw). An external surface of the columnar part h42 is a male screw. The cylindrical part h41 and the columnar part h42 are disposed coaxially with each other. The columnar part h42 has an exposed part ex2 exposed from the rubber part g4 (see FIG. 8). At least a part of the columnar part h42 is an exposed part ex. The exposed part ex is projected downward.

[0101] In the connection between the first extending member 10b and the grip body 10a, the columnar part h42 (male screw) is screwed into the screw hole sc3 (female screw) of the grip body 10a. In the connection of the extending members 10b, the columnar part h42 of the second extending member 10b is screwed into the screw hole sc4 of the first extending member 10b.

[0102] All the extending members 10b are common. The screw hole sc3 and the screw hole sc4 are the same kind.

[0103] An axial direction length of the exposed part ex2 is shorter than that of the screw hole sc3. Therefore, a clearance k1 exists between the bottom face part h32 and the columnar part h42 with the grip body 10a and the extending member 10b connected to each other (see FIG. 7). The clearance k1 prevents formation of a gap in a boundary between the external surface 10a1 of the grip body 10a and the external surface 10b1 of the extending member 10b.

[0104] The axial direction length of the exposed part ex2 is shorter than that of the screw hole sc4. Therefore, a clearance k2 exists between an end face of the columnar part h42 and a bottom face of the cylindrical part h41 with the extending members 10b connected to each other (see FIG. 7). The clearance k2 prevents formation of a gap in a boundary between the external surfaces 10b1 of the extending members 10b.

[0105] The second extending member 10b is located on a grip back end side of the first extending member 10b. The second extending member 10b is the extending member 10b located on the backmost side.

[0106] The second extending member 10b is the same as the first extending member 10b described above. Therefore, the description of the second extending member 10b is omitted.

[0107] Thus, in the embodiment, the grip body 10a and the extending member 10b can be connected to each other by the screw connection. Furthermore, the extending members 10b can be connected to each other by the screw connection.

[0108] In the second embodiment, the extending members 10b are detachably mounted. The extending members 10b are removed by rotating the extending members 10b to release the screw connection. A length Lg of a grip holding part can be adjusted by mounting and dismounting the extending members 10b.

[0109] In the embodiment, the case where the number of the extending members 10b is 2 is shown. The length Lg of the grip holding part can be changed by changing the number of the extending members 10b. When the number of the extending members 10b is 0, the length Lg can be shortened. The number of the extending members 10b may be 1.

[0110] The number of the extending members 10b may be equal to or greater than 3. Since the connecting structure of the extending members 10b is the same, the number of the extending members 10b to be connected can be optionally selected.

[0111] FIG. 9 is an exploded view of a grip 12 according to a third embodiment. The grip 12 has a grip body 10a, an extending member 10b and an extending member 12b. The grip body 10a is the same as that of the second embodiment described above. The extending member 10b is the same as that of the second embodiment described above.

[0112] The extending member 12b has a rubber part g5 and a hard connector h4. The hard connector h4 of the extending member 12b is the same as that of the extending member 10b described above. A difference between the extending member 10b and the extending member 12b is only a length of a rubber part.

[0113] A length of a rubber part g4 of the extending member 10b is shown by a double-pointed arrow L1 in FIG. 9. A length of the rubber part g5 of the extending member 12b is shown by a double-pointed arrow L2 in FIG. 9. The length L1 and the length L2 are different from each other. In the embodiment, a length of the grip 12 can be adjusted by selecting either one of the extending members 10b and 12b. Preferably, a ratio (L2/L1) is a noninteger. In this case, a length Lg which is not achieved by connection of the extending member 10b can be achieved by connection of the extending member 12b.

[0114] A material of the hard base body is harder than that of a holding surface of the grip. The use of the hard base body can enhance certainty of the connection and internal rigidity of the grip. A preferable material of the hard base body is a metal or a resin. A more preferable material is the metal. A thermoplastic resin and a carbon-fiber reinforced resin are exemplified as the resin. In respect of processability, nylon, polyether block copolymer (PEBAX), and polycarbonate or the like are exemplified as a desirable resin. Stainless steel, an aluminum alloy, and a titanium alloy or the like are exemplified as the metal. In respect of a swing balance, high specific gravity metals (specific gravity: equal to or greater than 12) such as tungsten and a tungsten alloy can be also used.

[0115] A material of the hard connector is harder than that of the holding surface of the grip. The use of the hard connector can enhance certainty of the connection and internal rigidity of the grip. A preferable material of the hard connector is a metal or a resin. A more preferable material is the metal. A thermoplastic resin and a carbon-fiber reinforced resin are exemplified as the resin. In respect of processability, nylon, polyether block copolymer (PEBAX), and polycarbonate or the like are exemplified as a desirable resin. Stainless steel, an aluminum alloy, and a titanium alloy or the like are exemplified as the metal. In respect of the swing balance, high specific gravity metals (specific gravity: equal to or greater than 12) such as tungsten and a tungsten alloy can be also used.

[0116] Rubber which is a material of the rubber part is not limited. Preferable rubber is a rubber elastic body made of vulcanized rubber or the like. It is natural that a thermoplastic elastomer is also included in the rubber. In respect of slip resistance or the like, natural rubber (specific gravity: 0.91 to 0.93), styrene-butadiene rubber (specific gravity: 0.92 to 0.97), EPDM (specific gravity: 0.86 to 0.87), polyisoprene rubber (specific gravity: 0.92 to 0.93), and a mixture thereof are preferable.

[0117] The rubber is normally a composition. The rubber composition may be mixed with oil. For example, aromatic oil, naphthenic oil, and paraffinic oil or the like can be used as the oil.

[0118] For example, the rubber composition of the grip may be suitably mixed with a reinforcing agent, a filler, a vulcanizing accelerator, and a vulcanizing assistant or the like if needed in addition to the rubber, sulfur, and the oil. Furthermore, the rubber composition may be mixed with an age inhibitor and a processing aid or the like.

[0119] For example, carbon and silica or the like can be used as the reinforcing agent. For example, hard clay, calcium carbonate, magnesium carbonate, and clay or the like are used as the filler. For example, zinc oxide and stearic acid or the like are used as the vulcanizing assistant. The vulcanizing accelerator can be suitably selected in response to rubber to be used, according to a known method.

[0120] The rubber may be a resin composition. Examples of the resin contained in the resin composition include a thermoplastic resin. The thermoplastic resin can be used for injection molding. A thermoplastic elastomer is preferable as the thermoplastic resin. A thermoplastic elastomer containing a soft segment and a hard segment is more preferable. In respect of coexistence of grip property and abrasion resistance, a urethane-based thermoplastic elastomer is more preferable.

[0121] As a preferable mixing ratio based on 100 parts by mass of the rubber, a mixing ratio of the reinforcing agent is 5 to 70 parts by mass; a mixing ratio of the filler is 10 to 70 parts by mass; a mixing ratio of the vulcanizing accelerator is 0.1 to 3 parts by mass; and a mixing ratio of the vulcanizing assistant is 1 to 10 parts by mass. However, the mixing ratio is not limited to the ratios thereof.

[0122] A process for producing the grip body is not limited. The grip body can be produced by a known method. Press forming and injection molding are exemplified as the method. A producing method including the step of setting a separately formed hard base body in a mold for a grip body and the step of fixing the hard base body to the grip body concurrently with molding the grip body in the mold can be also employed.

[0123] In the press forming, the mold is filled with the rubber composition. The mold filled with the rubber composition is pressurized and heated. A heating temperature is normally set to 130 to 200.degree. C., but the heating temperature is not limited thereto. A heating time is normally set to 3 to 15 minutes, but the heating time is not limited thereto.

[0124] A method for producing the extending member is not limited. Press forming and injection molding are exemplified as the method for producing the extending member. A producing method including the step of setting a separately formed hard connector in a mold for a rubber part and the step of fixing the hard connector to the rubber part concurrently with molding the rubber part in the mold may be employed.

[0125] Extension of a club length increases a swing balance. In the present invention, the mass of the hard connector offsets the increase in the swing balance with the increase in the club length. That is, the mass of the hard connector causes the suppression of the increase in the swing balance. In this respect, the specific gravity of the hard connector is preferably greater than the specific gravity of the rubber part. The specific gravity of the hard connector is more preferably equal to or greater than 1.5, still more preferably equal to or greater than 2.0, and yet still more preferably equal to or greater than 2.5. In respect of suppressing a club weight, the specific gravity of the hard connector is preferably equal to or less than 20.

[0126] The extending member of the embodiment is considered to operate as a dynamic vibration absorber. The form in which the hard connector is disposed inside the rubber part is considered to produce an operation as the dynamic vibration absorber. As a result, the extending member was found to be able to enhance vibration absorptivity of the grip.

[0127] In the grip 10 of the second embodiment, the hard base body h3 and the shaft 6 are separated from each other. Rubber exists between the hard base body h3 and the shaft 6 (see FIG. 7). The rubber can enhance the operation as the dynamic vibration absorber. The rubber can enhance the vibration absorptivity of the grip 10.

[0128] A thickness of rubber existing between the hard base body h3 and the shaft 6 is shown by a double-pointed arrow A1 in FIG. 7. In respect of the vibration absorptivity, the thickness A1 is preferably equal to or greater than 1 mm, more preferably equal to or greater than 1.5 mm, and still more preferably equal to or greater than 2 mm. When a central part of the grip is deformed, holding is not stabilized. In this respect, the thickness A1 is preferably equal to or less than 5 mm, more preferably equal to or less than 4 mm, and still more preferably equal to or less than 3 mm.

[0129] In the embodiment of FIG. 3, the hard base body h1 and the hard connector h2 are separated from each other. Rubber exists between the hard base body h1 and the hard connector h2. The rubber can enhance the operation as the dynamic vibration absorber. The rubber can enhance the vibration absorptivity of the grip 8.

[0130] In the embodiment of FIG. 3, the hard connectors h2 are separated from each other. Rubber exists between the hard connectors h2. The rubber can enhance the operation as the dynamic vibration absorber. The rubber can enhance the vibration absorptivity of the grip 8.

[0131] A thickness of the rubber existing between the hard base body h1 and the hard connector h2 is shown by a double-pointed arrow A2 in FIG. 3. In respect of the vibration absorptivity, the thickness A2 is preferably equal to or greater than 1 mm, more preferably equal to or greater than 1.5 mm, and still more preferably equal to or greater than 2 mm. When a central part of the grip is deformed, holding is not stabilized. In this respect, the thickness A2 is preferably equal to or less than 5 mm, more preferably equal to or less than 4 mm, and still more preferably equal to or less than 3 mm.

[0132] A thickness of the rubber existing between the hard connectors h2 is shown by a double-pointed arrow A3 in FIG. 3. In respect of the vibration absorptivity, the thickness A3 is preferably equal to or greater than 1 mm, more preferably equal to or greater than 1.5 mm, and still more preferably equal to or greater than 2 mm. When a central part of the grip is deformed, holding is not stabilized. In this respect, the thickness A3 is preferably equal to or less than 5 mm, more preferably equal to or less than 4 mm, and still more preferably equal to or less than 3 mm.

[0133] The thickness A1, the thickness A2, and the thickness A3 are measured with the extending member attached.

[0134] A total sum At of the rubber thickness is calculated by the following formula. That is, the total sum At (mm) of the rubber thickness is a total of the thickness A1 (mm), the thickness A2 (mm), and the thickness A3 (mm). In the calculation of the total sum At, the thickness A1, the thickness A2 or the thickness A3 may be 0.

At=A1+A2+A3

[0135] In respect of the vibration absorptivity, the thickness At is preferably equal to or greater than 1 mm, more preferably equal to or greater than 2 mm, and still more preferably equal to or greater than 3 mm. When a central part of the grip is deformed, holding is not stabilized. In this respect, the thickness At is preferably equal to or less than 10 mm, more preferably equal to or less than 9 mm, and still more preferably equal to or less than 8 mm.

[0136] As in all the embodiments described above, the connecting structure of the grip body and the extending member is preferably the same as the connecting structure of the extending members. When the plurality of extending members exist, the connecting structures thereof are preferably the same. The structures can enhance a freedom degree of the connection. The structures can enhance a freedom degree related to the connection order and the connecting number of the extending members.

[0137] In the embodiment described above, the plurality of extending members exist, and all the extending members are made same. In this case, since the extending members are the same, the mounting order of the extending members is optional, and the freedom degree for the adjustment of the grip is high.

[0138] On the other hand, the plurality of extending members may exist, and the outer diameters of the extending members may be different from each other. Examples thereof include a grip 14 shown in FIG. 10.

[0139] The grip 14 has a grip body 14a, a first extending member 14b, and a second extending member 14c. In the grip 14, outer diameters of the first extending member 14b and that of the second extending member 14c are different from each other. Internal structures of the grip body 14a and the extending members 14b and 14c are made to be similar to those of the grip 8 or the grip 10.

[0140] A holding surface 14m is formed by the grip body 14a and all the extending members 14b and 14c. The holding surface 14m is substantially steplessly formed. An external surface 14a1 of the grip body 14a and an external surface 14b1 of the extending member 14b adjacent to the grip body 14a are substantially steplessly connected. The external surface 14b1 and an external surface 14c1 of the mutually adjacent extending members are substantially steplessly connected.

[0141] In the grip 14, the outer diameter of the grip is increased as approximating to the grip end with the extending members 14b and 14c attached. The shape can contribute to easy-to-hold. Preferably, the difference of the outer diameter is achieved by the thickness of the rubber part. A difference between the outer shapes of the extending members is achieved by only the rubber part. In this case, the hard connector is made common in the first extending member 14b and the second extending member 14c.

EXAMPLES

[0142] Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be interpreted in a limited way based on the description of the examples.

[Evaluation]

[0143] A valuation method is as follows.

[Measurement of Swing Weight]

[0144] A swing weight was measured by using "BANCER-14" (trade name) manufactured by DAININ Corporation. The swing weight is a 14-inch type. The measured values are shown in the following Table 1.

[Measurement of Out-of-Plane Primary Vibration Attenuation Rate]

[0145] FIG. 11 shows a situation where an out-of-plane primary vibration attenuation rate is measured. In the measurement, a shaft 51 with a grip in which a grip 48 is attached to a shaft 6 is used. A string 50 is mounted to a grip side edge part of the shaft 51 with the grip. An acceleration pickup meter 52 is mounted to a spot of 370 mm from a grip end. The shaft 51 with the grip is hung by using the string 50. In a state where the shaft 51 with the grip is hung, the opposite side (back side) of the acceleration pickup meter 52 is hammered by an impact hammer 54 to excite the shaft 51 with the grip. Input vibration F is measured by a force pickup meter 56 mounted to the impact hammer 54. Response vibration .alpha. is measured by the acceleration pickup meter 52. The response vibration .alpha. is inputted into a frequency analysis device 62 via an amplifier 58. The input vibration F is inputted into the frequency analysis device 62 via an amplifier 60. A dynamic single analyzer (HP3562A) manufactured by Hewlett Packard Development Company was used as the frequency analysis device 62. A transfer function in a frequency region obtained in analysis was determined to obtain a vibration number of the shaft 51 with the grip. A vibration attenuation rate (.zeta.) determined by the following formula is an out-of-plane primary vibration attenuation rate.

.zeta.=(1/2).times.(.DELTA..omega./.omega.n)

To=Tn.times. 2

[0146] However, as shown in a graph of FIG. 12, con is a frequency of the primary maximum value. Meanings of .DELTA..omega., Tn and T0 are shown in the graph of FIG. 12.

[Sensuous Evaluation of Vibration Absorptivity by Actual Shot]

[0147] Each of twenty-five intermediate- or high-level golf players (satisfying conditions where the players have golf experience of more than 10 years and play golf at least once a month at present) hit balls by using clubs to which grips of the examples and the comparative example were attached. Each of the players hit five balls using each of the clubs and conducted sensuous evaluation of each of the clubs in terms of vibration absorptivity at five stages of a one score to a five score. A club thought to have higher vibration absorptivity provides a higher score. The average of the scores is shown in the following Table 1.

[Grip 70 according to Examples 1 and 2]

[0148] FIG. 13 is an enlarged view showing a vicinity of a grip end of a grip 70 according to example. FIG. 14 is a cross sectional view of FIG. 13. FIG. 15 is an exploded view of a grip 70.

[0149] The grip 70 has a structure similar to that of the grip 8 according to the first embodiment described above.

[0150] The grip 70 has a grip body 70a and two extending members 70b. The two extending members 70b are mounted to a back end of the grip body 70a.

[0151] The grip body 70a is fixed to a back end part of the shaft 6 by using a double-faced adhesive tape. An adhesion method of the double-faced adhesive tape is the same as a normal adhesion method of a grip.

[0152] The grip 70 has a connecting member 70c in addition to the grip body 70a and the extending members 70b. The connecting member 70c is a screw.

[0153] The grip body 70a has a rubber part g1 and a hard base body h1. A material of the rubber part g1 is rubber. The rubber part g1 has a cavity part cv1 (see FIG. 15). The hard base body h1 is provided inside the rubber part g1. The hard base body h1 is provided inside the shaft 6.

[0154] A producing method of the rubber part g1 is as follows.

[0155] Natural rubber (NR) and ethylene-propylene-diene rubber (EPDM) were mixed at a mass ratio of 65:35. Furthermore, sulfur, carbon black, and an inorganic component were suitably mixed therein to obtain a rubber composition. A press mold was filled with the rubber composition. The press mold filled with the rubber composition was then pressurized at 150.degree. C. for 10 minutes to obtain the rubber part g1 vulcanized and molded.

[0156] A length extended by one extending member 70b was set to 0.5 inch (12.7 mm). As shown in FIG. 13, when the two extending members 70b are attached, a club length is extended by 1.0 inch (25.4 mm).

[0157] The cavity part cv1 has an inner diameter enlarging part e1 having an inner diameter greater than an opening diameter (see FIG. 15). The cavity part cv1 has an undercut structure.

[0158] The first extending member 70b has a rubber part g2 and a hard connector h2. A material of the rubber part g2 is rubber. The rubber part g2 has a cavity part cv2. The hard connector h2 is provided inside the rubber part g2. The rubber part g2 covers a part of the hard connector h2.

[0159] The cavity part cv2 has an inner diameter enlarging part e2 having an inner diameter greater than an opening diameter. The cavity part cv2 has an undercut structure.

[0160] A producing method of the rubber part g2 is as follows. Natural rubber (NR) and ethylene-propylene-diene rubber (EPDM) were mixed at a mass ratio of 65:35. Furthermore, sulfur, carbon black, and an inorganic component were suitably mixed therein to obtain a rubber composition. A press mold was filled with the rubber composition. The press mold filled with the rubber composition was pressurized at 150.degree. C. for 10 minutes to obtain the rubber part g2 vulcanized and molded.

[0161] Differences between the grip 8 described above and the grip 70 according to the example 1 are a shape of the rubber part g1, a shape of the hard connector h2, and a shape of the rubber part g2. In the grip 70, a rubber thickness A2 (see FIG. 3) is 0 mm, and a rubber thickness A3 (see FIG. 3) is 0 mm. That is, in the grip 70, the hard base body h1 and the hard connector h2 are brought into contact with each other, and the hard connectors h2 are also brought into contact with each other. Regarding the other points, the grip 8 is the same as the grip 70. Also in the grip 70, the connection by the screw and the connection using the undercut structure are employed.

[0162] A metal was used as a material of the hard base body h1. An aluminum alloy was used as the metal.

[0163] A metal was used as a material of the hard base body h2. An aluminum alloy was used as the metal. An adhesive was used for connecting the hard connector h2 and rubber part g2 to each other.

[0164] FIG. 16 is a view independently showing the hard connector h2 used for the extending member 70b. The hard connector h2 has a great diameter part h21, an inclined part h22, an intermediate diameter part h23, and a small diameter part h24. The great diameter part h21 is cylindrical. The inclined part h22 is conical. The intermediate diameter part h23 is cylindrical. The small diameter part h24 is cylindrical. The great diameter part h21, the inclined part h22, the intermediate diameter part h23, and the small diameter part h24 are disposed coaxially with each other. Although not shown in the drawings, a screw hole is formed at a center of the hard connector h2.

[0165] A length d21 of the great diameter part h21 was set to 1.0 mm; a length d22 of the inclined part h22 was set to 1.0 mm; a length d23 of the intermediate diameter part h23 was set to 1.5 mm; and a length d24 of the small diameter part h24 was set to 9.2 mm. The length d21, the length d22, the length d23, and the length d24 were measured along a central axial line of the hard connector h2. The drawings such as FIG. 16 do not reflect the ratios of the lengths.

Example 1

[0166] "SRIXON ZR-700 Driver" (trade name) manufactured by SRI Sports Limited was used. A grip of the "SRIXON ZR-700 Driver" was removed. In place of the grip, the grip body 70a was mounted. One of the extending members 70b was attached to the grip body 70a to obtain a golf club of example 1. Evaluation of the example 1 is shown in the following Table 1.

Example 2

[0167] One more extending member 70b was further mounted to the grip of the example 1 to obtain a golf club of example 2. In the grip of the example 2, as shown in FIG. 14, the two extending members 70b are attached. Evaluation of the example 2 is shown in the following Table 1.

[0168] s[Grip 80 according to Examples 3 and 4]

[0169] FIG. 17 is an enlarged view showing a vicinity of a grip end of a grip 80 according to example. FIG. 18 is a cross sectional view of FIG. 17. FIG. 19 is an exploded view of the grip 80.

[0170] The grip 80 is the same type as the grip 8 according to the first embodiment described above.

[0171] The grip 80 has a grip body 80a and two extending members 80b. The two extending members 80b are mounted to a back end of the grip body 80a.

[0172] The grip body 80a is fixed to a back end part of a shaft 6 by using a double-faced adhesive tape. An adhesion method of the double-faced adhesive tape is the same as a normal adhesion method of a grip.

[0173] The grip 80 has a connecting member 80c in addition to the grip body 80a and the extending members 80b. The connecting member 80c is a screw.

[0174] The grip body 80a has a rubber part g1 and a hard base body h1. A material of the rubber part g1 is rubber. The rubber part g1 has a cavity part cv1 (see FIG. 19). The rubber part g1 was produced as in the rubber part g1 of the grip body 70a.

[0175] The hard base body h1 is provided inside the rubber part g1. An axial direction length A4 (see FIG. 19) of the hard base body h1 was set to 5.0 mm.

[0176] A length extended by one extending member 80b was set to 0.5 inch (12.7 mm). As shown in FIG. 17, when the two extending members 80b are attached, a club length is extended by 1.0 inch.

[0177] The cavity part cv1 has an inner diameter enlarging part e1 having an inner diameter greater than an opening diameter (see FIG. 19). The cavity part cv1 has an undercut structure.

[0178] The first extending member 80b has a rubber part g2 and a hard connector h2. A material of the rubber part g2 is rubber. The rubber part g2 has a cavity part cv2. The hard connector h2 is provided inside the rubber part g2. The rubber part g2 covers a part of the hard connector h2.

[0179] The cavity part cv2 has an inner diameter enlarging part e2 having an inner diameter greater than an opening diameter. The cavity part cv2 has an undercut structure.

[0180] The rubber part g2 was produced as in the rubber part g2 of the grip body 70b.

[0181] Differences between the grip 8 described above and the grip 80 according to the example 1 are a shape of the rubber part g1, a shape of the hard connector h2, and a shape of the rubber part g2. In the grip 80, a rubber thickness A2 (see FIGS. 3 and 18) is 0 mm, and a rubber thickness A3 (see FIGS. 3 and 18) is 4 mm. That is, in the grip 80, the hard base body h1 and the hard connector h2 are brought into contact with each other. However, the hard connectors h2 are not brought into contact with each other. Rubber having a thickness A3 of 4 mm is interposed between the hard connectors h2. Regarding the other points, the grip 80 is the same as the grip 8. Also in the grip 80, the connection by the screw and the connection using the undercut structure are employed.

[0182] A metal was used as a material of the hard base body h1. An aluminum alloy was used as the metal.

[0183] A metal was used as a material of the hard base body h2. An aluminum alloy was used as the metal. An adhesive was used for connecting the hard connector h2 and rubber part g2 to each other.

[0184] FIG. 20 is a view independently showing the hard connector h2 used for the extending member 80b. The hard connector h2 has a great diameter part h25, an inclined part h26, an intermediate diameter part h27, and a small diameter part h28. The great diameter part h25 is cylindrical. The inclined part h26 is conical. The intermediate diameter part h27 is cylindrical. The small diameter part h28 is cylindrical. The great diameter part h25, the inclined part h26, the intermediate diameter part h27, and the small diameter part h28 are disposed coaxially with each other. Although not shown in the drawings, a screw hole is formed at a center of the hard connector h2.

[0185] A length d25 of the great diameter part h25 was set to 1.0 mm; a length d26 of the inclined part h26 was set to 1.0 mm; a length d27 of the intermediate diameter part h27 was set to 1.5 mm; and a length d28 of the small diameter part h28 was set to 5.2 mm. The length d25, the length d26, the length d27, and the length d28 were measured along a central axial line of the hard connector h2. The drawings such as FIG. 20 do not reflect the ratios of the lengths.

Example 3

[0186] "SRIXON ZR-700 Driver" (trade name) manufactured by SRI Sports Limited was used. A grip of the "SRIXON ZR-700 Driver" was removed. In place of the grip, the grip body 80a was mounted. One of the extending members 80b was attached to the grip body 80a to obtain a golf club of example 3. Evaluation of the example 3 is shown in the following Table 1.

Example 4

[0187] One more extending member 80b was further mounted to the grip of the example 3 to obtain a golf club of example 4. In the grip of the example 4, as shown in FIG. 18, two extending members 80b are attached. Evaluation of the example 4 is shown in the following Table 1.

Example 5

[0188] A golf club of example 5 was obtained in the same manner as in the example 4 except that a rubber part was provided between a hard base body h1 and a hard connector h2 so that a rubber thickness A2 (see FIG. 18) was set to 4.0 mm. Evaluation of the example 5 is shown in the following Table 1.

Example 6

[0189] A golf club of example 6 was obtained in the same manner as in the example 4 except that a thickness of a rubber part g2 was adjusted so that a rubber thickness A3 (see FIG. 18) was set to 1.0 mm. Evaluation of the example 6 is shown in the following Table 1.

Comparative Example 1

[0190] "SRIXON ZR-700 Driver" manufactured by SRI Sports Limited was used as is as a commercial item. A grip of the comparative example 1 is a grip attached to "SRIXON ZR-700 Driver" as standard. Evaluation of the comparative example 1 is shown in the following Table 1.

TABLE-US-00001 TABLE 1 Specifications and evaluation results of examples and comparative examples Comparative Unit Example 1 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Extending member Number Piece 0 1 2 1 2 2 2 Total length inch 0 0.5 1 0.5 1 1 1 Total weight g 0 10 20 11 22 28 21 Club length inch 45 45.5 46 45.5 46 46 46 Club weight g 319 329 339 330 343 349 342 Swing weight 14-inch D2 D2 D2 D2 D2 D3 D2 type Thickness A1 mm -- 0 0 0 0 0 0 Thickness A2 mm -- 0 0 0 0 4 0 Thickness A3 mm -- -- 0 -- 4 4 1 At = A1 + A2 + A3 mm -- 0 0 0 4 8 1 Out-of-plane primary % 0.51 0.86 1.32 1.12 1.48 1.67 1.40 attenuation rate Actual shot evaluation -- 3.0 3.8 4.1 4.0 4.4 4.6 4.2 (vibration absorptivity)

[0191] As shown in Table 1, the examples are high1y evaluated as compared with the comparative examples. From the evaluation results, the advantages of the present invention are apparent.

[0192] The invention described above can be applied to all the golf club. The present invention can be used for a wood type golf club, an iron type golf club, and a putter club or the like.

[0193] The description hereinabove is mere1y for an illustrative example, and various modifications can be made in the scope not to depart from the principles of the present invention.

Claims

1. A golf club comprising: a head; a shaft; a grip body; and an extending member, wherein the extending member is detachably mounted to a back end of the grip body; and a length of a holding surface of a grip can be adjusted by mounting and dismounting the extending member.

2. The golf club according to claim 1, further comprising a hard base body, wherein the extending member has a hard connector; and the extending member can be mounted to the back end of the grip body by connecting the hard base body and the hard connector to each other.

3. The golf club according to claim 1, wherein the extending member has a hard connector; the grip body has a cavity part having an undercut structure; the cavity part is made of rubber; the hard connector can be mounted to the cavity part by using elastic deformation of the rubber; and due to the undercut structure, the hard connector can be less likely to come off the cavity part.

4. The golf club according to claim 2, wherein the hard base body and the shaft are separated from each other; and rubber exists between the hard base body and the shaft.

5. The golf club according to claim 2, wherein the hard base body and the hard connector are separated from each other with the extending member mounted to the grip body; and rubber exists between the hard base body and the hard connector.

6. The golf club according to claim 1, wherein the golf club includes the plurality of extending members; the extending members are detachably mounted to each other; and a length of the grip can be adjusted by connecting number of the extending members.

7. The golf club according to claim 6, wherein the hard connectors are separated from each other with the extending members connected to each other; and rubber exists between the hard connectors.

8. The golf club according to claim 6, wherein each of the plurality of extending members has a cavity part having an undercut structure; the cavity part is made of rubber; the hard connector of the first extending member can be mounted to the cavity part of the second extending member by using elastic deformation of the rubber; and due to the undercut structure, the second extending member can be less likely to come off the first extending member.

9. The golf club according to claim 1, wherein the golf club includes the plurality of extending members having lengths different from each other; and a length of the grip can be adjusted by selection or combination of the extending members.

10. The golf club according to claim 2, wherein the golf club includes the plurality of extending members, and wherein when a thickness of rubber existing between the hard base body and the shaft is defined as A1 (mm); a thickness of rubber existing between the hard base body and the hard connector is defined as A2 (mm); and a thickness of rubber existing between the adjacent hard connectors is defined as A3 (mm), a total sum At of the thickness A1, the thickness A2, and the thickness A3 is 1 mm or greater and 10 mm or less.

11. The golf club according to claim 4, wherein when a thickness of the rubber existing between the hard base body and the shaft is defined as A1 (mm), the thickness A1 is 1 mm or greater and 5 mm or less.

12. The golf club according to claim 5, wherein when a thickness of the rubber existing between the hard base body and the hard connector is defined as A2 (mm), the thickness A2 is 1 mm or greater and 5 mm or less.

13. The golf club according to claim 1, wherein the golf club includes the plurality of extending members; the extending members are detachably mounted to each other; a length of the grip can be adjusted by connecting number of the extending members; each of the extending members has a hard connector; and when a thickness of rubber existing between the adjacent hard connectors is defined as A3 (mm), the thickness A3 is 1 mm or greater and 5 mm or less.

14. The golf club according to claim 1, wherein the grip body and the extending member can be connected to each other by screw connection.

15. The golf club according to claim 6, wherein the extending members can be connected to each other by screw connection.

16. The golf club according to claim 2, further comprising a connecting member, wherein the connecting member connects the hard base body and the hard connector to each other.