GOLF CLUB

The present application claims priority on Patent Application No. 2013-155141 filed in JAPAN on Jul. 26, 2013, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a golf club.

2. Description of the Related Art

A golf club having adjustability has been proposed. The adjustability facilitates fitting.

US2013/0017901 and US7980959 disclose golf clubs including a head and a shaft detachably attached to the head. In these golf clubs, a sleeve is attached to a tip part of the shaft, and a shaft hole formed in the sleeve is inclined. In these golf clubs, a loft angle, a lie angle, and a face angle can be adjusted by circumferential direction fixed positions of the sleeve.

SUMMARY OF THE INVENTION

In respect of convenience, it is preferable that a state of adjustment can be easily understood. It is an object of the present invention to provide a golf club having excellent adjustment convenience.

A preferable golf club includes a shaft; a head including a hosel; a sleeve fixed to a tip part of the shaft; a grip fixed to a back end part (butt end part) of the shaft; and a connecting member which can be connected to the sleeve. The shaft is detachably attached to the head. The sleeve can be fixed to the head at a plurality of circumferential direction fixed positions. A three-dimensional angle of the shaft to the head is changed depending on the circumferential direction fixed positions of the sleeve. The shaft includes an exposed part exposed to the outside. The exposed part includes a shaft marking for confirming the circumferential direction fixed positions.

Preferably, the head includes a head marking. Preferably, the head marking is disposed on the hosel. Preferably, the shaft marking is disposed on a tip part of the exposed part.

Preferably, the grip includes a grip marking for confirming the circumferential direction fixed positions.

Preferably, the grip marking is disposed on a tip part of the grip.

Preferably, the shaft marking is formed after the sleeve is fixed to the shaft.

Preferably, the shaft marking is formed after the sleeve fixed to the shaft is attached to the head.

Preferably, the shaft marking is formed by a laser.

Another preferable golf club includes a shaft; a head including a hosel; a sleeve fixed to a tip part of the shaft; a grip fixed to a back end part of the shaft; and a connecting member which can be connected to the sleeve. The shaft is detachably attached to the head. The sleeve can be fixed to the head at a plurality of circumferential direction fixed positions. A three-dimensional angle of the shaft to the head can be changed depending on the circumferential direction fixed positions of the sleeve. The shaft includes an exposed part exposed to the outside. The exposed part includes a shaft marking. The head includes a head marking. The head marking is disposed on the hosel. The shaft marking is disposed on a tip part of the exposed part.

Preferably, a color of the shaft marking changes depending on the angle of viewing. A color of the shaft marking viewed from an angle of a standard address viewpoint is defined as SR1; a color of the shaft marking viewed from the front is defined as SR2; a color of the shaft around the shaft marking is defined as SR3; a color difference between the color SR1 and the color SR3 is defined as ΔEa; and a color difference between the color SR2 and the color SR3 is defined as ΔEb. Preferably, ΔEa is less than ΔEb.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a golf club according to a first embodiment, and shows only a vicinity of a head;

FIG. 2 is an exploded view of FIG. 1;

FIG. 3 is a cross-cross-sectional view of FIG. 1;

FIG. 4 is a perspective view showing an example of a sleeve;

FIG. 5 is a bottom view of the sleeve of FIG. 4;

FIG. 6 is a cross-cross-sectional view taken along line VI-VI of FIG. 5;

FIG. 7 is a cross-cross-sectional view taken along line VII-VII of FIG. 5;

FIG. 8 is a cross-cross-sectional view taken along line F8-F8 of FIG. 3;

FIG. 9 is a side view of the golf club of FIG. 1 viewed from a heel side, and a sole is positioned on an upper side in FIG. 9;

FIG. 10 is a view showing a golf club according to a second embodiment;

FIG. 11 is a side view of the golf club of FIG. 10 viewed from a heel side, and a sole is positioned on an upper side in FIG. 11 as in FIG. 9; and

FIG. 12 is a developed view of a shaft marking (and/or a grip marking) according to a modification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

Unless otherwise described, “a circumferential direction” in the present application means a circumferential direction of a shaft. Unless otherwise described, “an axial direction” in the present application means an axial direction of the shaft.

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

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

The head 4 includes a head body 14 and an engaging member 16. The head body 14 includes a hosel 17. The hosel 17 has a hosel hole 18 into which the sleeve 8 is inserted.

The head body 14 has a through hole 19 into which the screw 10 is inserted. The through hole 19 passes through a bottom part of the hosel hole 18. The head body 14 has a sole opening 20 (see FIG. 3). The sole opening 20 and the hosel hole 18 are continued through the through hole 19. The head body 14 has a hollow part.

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

The shaft 6 is not limited. A generalized carbon shaft, and a steel shaft or the like can be used. The shaft 6 of the embodiment is a carbon shaft.

The shaft 6 includes an exposed part Ex and an unexposed part Ey (see FIG. 3). The exposed part Ex is exposed to the outside. The exposed part Ex is recognized from the outside. The unexposed part Ey is not exposed to the outside. The unexposed part Ey is covered with the sleeve 8, the ferrule 12, or the grip.

The screw 10 includes a head part 22 and an axis part 24 (see FIG. 2). The screw 10 passes through the through hole 19 from the sole opening 20, and leads to a screw hole 32 (to be described later). The screw 10 is connected to the sleeve 8 in a screwing manner. The head part 22 has a rotating recess 26 (see FIG. 3). The screw 10 positioned in the head body 14 can be axially rotated by using a tool fitted into the recess 26. This axial rotation enables attachment and detachment of the sleeve 8. The screw 10 is an example of a connecting member which can be connected to the sleeve 8. The connection is mechanical connection.

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

The engaging member 16 includes a rotation-preventing part. The rotation-preventing part is formed in the inner surface of the engaging member 16. The rotation-preventing part will be described later.

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

The sleeve 8 has a shaft hole 30 and the screw hole 32 (FIGS. 6 and 7). The shaft hole 30 is opened to one side (an upper side). The screw hole 32 is opened to other side (a lower side). The screw hole 32 is disposed on the lower side of the shaft hole 30.

The sleeve 8 further includes a circumferential surface 34, an inclined surface 35, an exposed surface 36, and a rotation-preventing part 38. The circumferential surface 34 is a portion having a fixed outer diameter. A step surface 39 exists on the lower end of the exposed surface 36.

An attached state where the shaft 6 is attached to the head 4 is shown in FIGS. 1 and 3. In the attached state, the exposed surface 36 is exposed to the outside. An outer diameter of a lower end of the exposed surface 36 is substantially equal to an outer diameter of a hosel end surface 37. An outer diameter of an upper end of the exposed surface 36 is substantially equal to an outer diameter of a lower end of the ferrule 12. The exposed surface 36 and the ferrule 12 look like a general ferrule as a whole. The exposed surface 36 enhances appearance.

A lower portion of the sleeve 8 than the exposed surface 36 is inserted into the hosel hole 18 (see FIG. 3). A shape of the inclined surface 35 corresponds to a shape of a chamfering part 41 of the hosel hole 18.

As shown in FIG. 6, an axis line h1 of the shaft hole 30 is inclined to an axis line z1 of an outer surface of the sleeve 8. Therefore, an axis line s1 of the shaft 6 is inclined to the axis line z1. An axis line e1 of the hosel hole 18 coincides with the axis line z1. The axis line s1 of the shaft 6 is inclined to the axis line e1 of the hosel hole 18.

An angle between the axis line e1 and the axis line s1 is shown by a double pointed arrow 91 in FIG. 6. In respect of appropriate adjustability, the inclination angle θ1 is preferably 0.5 degree or greater and 2 degrees or less.

The tip part of the shaft 6 is fixed to the shaft hole 30. The fixation is achieved by bond using an adhesive agent. An outer surface of the shaft 6 is bonded to an inner surface of the shaft hole 30. The fixation may be achieved by means other than bond.

The prevention of coming off of the sleeve 8 is achieved by screw connection. As shown in FIG. 3, the screw hole 32 of the sleeve 8 is connected to the screw 10 in a screwing manner. The screw connection prevents the coming off of the sleeve 8. An axial force caused by the screw connection is balanced with pressure between the hosel end surface 37 and the step surface 39. In order to secure the axial force, a clearance K1 exists between a tip of the screw 10 and a bottom surface of the screw hole 32 in a state where the screw connection is completed (see FIG. 3).

As shown in FIGS. 4 and 5, the rotation-preventing part 38 of the sleeve 8 includes a plurality of projections t2. The rotation-preventing part 38 includes twelve projections t2. The plurality of projections t2 are equally disposed in a circumferential direction. In the embodiment, the plurality of projections t2 are disposed at intervals of 30 degrees.

The rotation-preventing part 38 has rotational symmetric property with the axis line z1 as a rotational symmetric axis. The rotational symmetric property means that the shape of the rotation-preventing part rotated by (360/W) degrees about the rotational symmetric axis coincides with the shape of the unrotated rotation-preventing part. W is an integer of equal to or greater than 2. The coincidence of the shape of the rotation-preventing part 38 rotated by (360/W) degrees about the rotational symmetric axis with the shape of the unrotated rotation-preventing part 38 is also referred to as “W-fold rotation-symmetry”. The rotation-preventing part 38 of the embodiment has twelve-fold rotation-symmetry with respect to the axis line z1.

FIG. 8 is a cross-cross-sectional view taken along line F8-F8 of FIG. 3.

An outer surface of the engaging member 16 is a circumferential surface having a fixed outer diameter. Meanwhile, a rotation-preventing part 48 is provided inside of the engaging member 16. The rotation-preventing part 48 has twelve recesses r2. These recesses r2 are disposed at equal intervals in a circumferential direction. The engaging member 16 may be integrally formed with the head body 14.

The rotation-preventing part 48 has rotational symmetric property with the axis line z1 as a rotational symmetric axis. The rotation-preventing part 48 has twelve-fold rotation-symmetry with respect to the axis line z1. The shape of the rotation-preventing part 48 corresponds to the shape of the rotation-preventing part 38.

Regulation of relative rotation between the sleeve 8 and the hosel hole 18 is achieved by the engagement between the rotation-preventing part 38 and the rotation-preventing part 48. The rotation-preventing part 38 and the rotation-preventing part 48 are engaged with each other. The relative rotation between the head 4 and the shaft 6 is regulated by the engagement. The rotation of the sleeve 8 to the head 4 is regulated by the engagement between the rotation-preventing part 48 and the rotation-preventing part 38. The shaft 6 is not rotated with respect to the head 4 by hitting.

The sleeve 8 can be fixed at a plurality of circumferential direction fixed positions. In the embodiment, the sleeve 8 has twelve circumferential direction fixed positions. In other words, the number of the circumferential direction relative positions in which the rotation-preventing part 38 and the rotation-preventing part 48 can be engaged with each other is twelve. If the circumferential direction fixed position of the sleeve 8 is changed, a three-dimensional angle of the shaft 6 to the head 4 is changed depending on the inclination angle θ1. A loft angle, a lie angle, and a hook angle are changed by the change in the three-dimensional angle.

Examples of the number of the circumferential direction fixed positions of the sleeve 8 include 4, 5, 6, and 8 besides 12. In respect of improving adjustability, the number of the circumferential direction fixed positions of the sleeve 8 is preferably equal to or greater than 4, and more preferably equal to or greater than 8. In respect of preventing the shape of the rotation-preventing part from being complicated, the number of the circumferential direction fixed positions of the sleeve 8 is preferably equal to or less than 24, and more preferably equal to or less than 20.

FIG. 9 is a side view of the golf club 2 viewed from a heel side. A sole of the golf club 2 is positioned on an upper side in FIG. 9.

As described above, the sleeve 8 can be fixed to the head 4 at the plurality of circumferential direction fixed positions. The three-dimensional angle of the shaft 6 to the head 4 is changed depending on the circumferential direction fixed positions of the sleeve 8. A real loft angle, a lie angle, and a face angle are changed due to the change in the three-dimensional angle. Thus, the golf club 2 has an angle adjusting function which can adjust the real loft angle, the lie angle, and the face angle.

As shown in FIG. 9, the head 4 includes a head marking Hm. The head marking Hm is provided on the hosel 17. The head marking Hm is provided on an outer peripheral surface of the hosel 17. The head marking Hm is provided at one place in the circumferential direction. The head marking Hm may be provided at a plurality of places in the circumferential direction.

In the embodiment, the head marking Hm is a star sign. A shape of the head marking Hm is not limited. The head marking Hm can be recognized by viewing.

As shown in FIG. 9, the shaft 6 includes a shaft marking Sm. The shaft marking Sm is provided in order to confirm a circumferential direction fixed position Pv of the sleeve 8.

The shaft marking Sm is provided on the surface of the shaft 6. The shaft marking Sm is provided on a tip part of the exposed part Ex. The shaft marking Sm is provided at one place in the circumferential direction. The shaft marking Sm may be provided at a plurality of places in the circumferential direction.

In the embodiment, the shaft marking Sm is a line. A shape of the shaft marking Sm is not limited. The shaft marking Sm can be recognized by viewing.

If the sleeve 8 is positioned at the at least one circumferential direction fixed position, a relative position between the head marking Hm and the shaft marking Sm can be confirmed by viewing. As shown in FIG. 9, both the head marking Hm and the shaft marking Sm can be recognized from one viewpoint. Therefore, the relative position between the head marking Hm and the shaft marking Sm is confirmed.

Hereinafter, a circumferential direction position of the sleeve 8 is defined as Pv. Hereinafter, a circumferential direction position of the head marking Hm is defined as Ph. Hereinafter, a circumferential direction position of the shaft marking Sm is defined as Ps. Hereinafter, a circumferential direction position of a grip marking Gm (to be described later) is defined as Pg.

In the state of FIG. 9, the circumferential direction position Ph of the head marking Hm and the circumferential direction position Ps of the shaft marking Sm coincide with each other. Preferably, the circumferential direction fixed position Pv of the sleeve 8 at which the circumferential direction position Ph and the circumferential direction position Ps coincide with each other exists. In the embodiment, the number of the circumferential direction fixed positions Pv is 12. The circumferential direction position Ph and the circumferential direction position Ps coincide with each other at one circumferential direction fixed position Pv.

The circumferential direction fixed position Pv of the sleeve 8 can be easily recognized by the relative position between the head marking Hm and the shaft marking Sm. Therefore, the real loft angle, the lie angle, and the face angle are easily adjusted.

FIG. 10 shows a golf club 52 of a second embodiment. The golf club 52 includes a head 54, a shaft 56, a sleeve 58, a grip 60, a screw (not shown), and a ferrule 62.

The head 54 is the same as the head 4 described above. The head 54 includes a head marking Hm. The head marking Hm is provided in order to judge a circumferential direction fixed position Pv of the sleeve 58. The shaft 56 is the same as the shaft 6 described above. The shaft 56 includes a shaft marking Sm. The shaft marking Sm is provided in order to judge the circumferential direction fixed position Pv of the sleeve 58. The sleeve 58 is the same as the sleeve 8 described above. The screw (not shown) is the same as the screw 10 described above. The ferrule 62 is the same as the ferrule 12 described above.

FIG. 11 is a side view of the golf club 52 viewed from a heel side. The grip 60 includes a grip marking Gm. The grip marking Gm is provided in order to confirm the circumferential direction fixed position Pv of the sleeve 58. The grip marking Gm is provided on a surface of the grip 60. The grip marking Gm can be visually recognized from the outside. The grip marking Gm is provided at one place in a circumferential direction. The grip marking Gm may be provided at a plurality of places in the circumferential direction.

In the embodiment, the grip marking Gm is a line. A shape of the grip marking Gm is not limited. The grip marking Gm can be recognized by viewing. The grip marking Gm is provided in order to judge the circumferential direction fixed position Pv of the sleeve 58.

In the embodiment, a circumferential direction position Pg of the grip marking Gm is the same as a circumferential direction position Ps of the shaft marking Sm. Therefore, the circumferential direction fixed position Pv of the sleeve 58 is easily recognized. The circumferential direction position Pg may be different from the circumferential direction position Ps.

The shaft marking Sm may be disposed at a position which is less likely to be viewed from a golf player at address. The shaft marking Sm is positioned on a back side as viewed from the golf player at address in a state shown in FIG. 11. The circumferential direction fixed position Pv of the sleeve includes a circumferential direction position where the shaft marking Sm is not viewed from the golf player at address. In the circumferential direction position, the golf player gripping and addressing the golf club 52 cannot view the shaft marking Sm. The shaft marking Sm does not excessively disturb the golf player's concentration at address.

The head marking Hm may be disposed at a position which is less likely to be viewed from the golf player at address. As shown in FIG. 11, the head marking Hm is positioned on a back side as viewed from the golf player at address. The head marking Hm is disposed at a position which is not viewed from the golf player at address. The golf player gripping and addressing the golf club 52 cannot view the head marking Hm. Therefore, the head marking Hm does not disturb the golf player's concentration at address.

The grip marking Gm may be disposed at a position which is less likely to be viewed from the golf player at address. In a state shown in FIG. 11, the grip marking Gm is positioned on a back side as viewed from the golf player at address. The circumferential direction fixed position Pv of the sleeve includes a circumferential direction position where the grip marking Gm is not viewed from the golf player at address. At the circumferential direction position, the golf player gripping and addressing the golf club 52 cannot view the grip marking Gm. Therefore, the grip marking Gm does not excessively disturb the golf player's concentration at address.

The following discriminating method discriminates whether the marking can be viewed from the golf player at address or not. In the discriminating method, a club is set to a reference state, and a standard address viewpoint is set. The discrimination is given by viewing the club set to the reference state from the standard address viewpoint. The discriminate can be given by an image of a camera in which a center of a lens is set to the standard address viewpoint.

In the reference state, the golf club is placed on a level surface HP at a specified lie angle. The axis line s1 of the shaft is disposed in a plane VP perpendicular to the level surface HP. The shaft 6 is supported in a state where the lie angle is held, the shaft can move in the direction of the axis line s1, and the shaft 6 can rotate about the axis line s1. A sole is grounded on the level surface HP so that the head 4 is most stable while the support of the shaft 6 is maintained. The state where the head 4 is most stable is the reference state. In the club set to the reference state, a position separated by 60 cm on an upper side in a vertical direction from a grip end is defined as the standard address viewpoint.

[Axial Direction Position of Shaft Marking Sm]

An axial direction distance between an exposed end of the sleeve 58 and the shaft marking Sm is shown by a double pointed arrow D1 in FIG. 11. The exposed end of the sleeve 58 is an end of a portion exposed in an assembled state. The exposed end is an end of the sleeve 58 on the grip 60 side.

In respect of being capable of easily recognizing the relative position with the head marking Hm, the shaft marking Sm is preferably disposed near the exposed end of the sleeve 58. The term “near” means that the axial direction distance D1 is equal to or less than 15 cm.

In respect of being capable of easily recognizing a relative position with the head marking Hm, the distance D1 is preferably equal to or less than 15 cm, more preferably equal to or less than 13 cm, still more preferably equal to or less than 10 cm, yet still more preferably equal to or less than 5 cm, yet still more preferably equal to or less than 3 cm, and yet still more preferably equal to or less than 1 cm. The distance D1 may be 0 cm.

An axial direction distance between a tip of the exposed part Ex of the shaft 56 and the shaft marking Sm is shown by a double pointed arrow D5 in FIG. 11. In respect of being capable of easily recognizing the relative position with the head marking Hm, the distance D5 is preferably equal to or less than 10 cm, more preferably equal to or less than 8 cm, still more preferably equal to or less than 7 cm, yet still more preferably equal to or less than 5 cm, yet still more preferably equal to or less than 3 cm, yet still more preferably equal to or less than 1 cm, and yet still more preferably equal to or less than 0.5 cm. In the embodiment of FIG. 11, the distance D5 is 0 cm.

In respect of being capable of easily recognizing the relative position with the head marking Hm, the shaft marking Sm is preferably disposed on the tip part of the exposed part Ex. If the distance D5 is equal to or less than 10 cm, the shaft marking Sm is determined to be disposed on the tip part of the exposed part Ex.

[Axial Direction Position of Head Marking Hm]

An axial direction distance between a hosel end surface and the head marking Hm is shown by a double pointed arrow D2 in FIG. 11. In respect of being capable of easily recognizing the relative position with the shaft marking Sm, the distance D2 is preferably equal to or less than 3 cm, more preferably equal to or less than 2 cm, and still more preferably equal to or less than 1 cm. The distance D2 may be 0 cm.

[Axial Direction Position of Grip Marking Gm]

An axial direction distance between a tip 66 of the grip 60 and the grip marking. Gm is shown by a double pointed arrow D3 in FIG. 11. The tip 66 is a head side end surface. In respect of being capable of easily recognizing the circumferential direction fixed position Pv, the distance D3 is preferably equal to or less than 3 cm, more preferably equal to or less than 2 cm, and still more preferably equal to or less than 1 cm. The distance D3 may be 0 cm. In the embodiment of FIG. 11, the distance D3 is 0 cm. In other words, the grip marking Gm border the tip 66.

In respect of being capable of easily recognizing the circumferential direction fixed position Pv, the grip marking Gm is preferably disposed on the tip part of the grip 60. If the distance D3 is equal to or less than 3 cm, the grip marking Gm is determined to be disposed on the tip part of the grip 60.

An axial direction distance between the head marking Hm and the shaft marking Sm is shown by a double pointed arrow D4 in FIG. 11. In respect of being capable of easily recognizing a positional relationship between the marking Hm and the marking Sm, the distance D4 is preferably equal to or less than 20 cm, more preferably equal to or less than 15 cm, still more preferably equal to or less than 10 cm, yet still more preferably equal to or less than 5 cm, and yet still more preferably equal to or less than 3 cm. In light of the existence of the ferrule and the sleeve, the distance D4 is preferably equal to or greater than 0.5 cm.

[Method for Forming Shaft Marking Sm]

A method for forming the shaft marking Sm is not limited. One recognized by viewing can function as the shaft marking Sm. The shaft marking Sm may be two-dimensional indication or three-dimensional indication. Examples of the three-dimensional indication include a recess (including a groove) and a projection. The three-dimensional indication may be formed by the shaft itself, or may be formed by an indication member attached to the shaft. Examples of the indication member include a seal applied on the shaft. Examples of the method for forming the two-dimensional indication include a method using a laser, ink-jet printing, coating, and screen printing.

A preferable example of the shaft marking Sm is formed by a laser. In the method, the shaft marking Sm is formed by the irradiation of the laser. For example, a commercially available laser marker may be used. The marking can be simply, correctly, and rapidly formed by the laser. The method using the laser can be easily applied also to the assembled club, for example. Therefore, the method using the laser is suitable for the following items (a) and (b).

(a) After the sleeve is fixed to the shaft, the shaft marking Sm is formed; and

(b) After the sleeve fixed to the shaft is attached to the head, the shaft marking Sm is formed.

Since the shaft marking Sm is applied after the sleeve is fixed in the case of the item (a), the relative position of the shaft marking Sm to the sleeve is accurately set.

Since the shaft marking Sm is applied after the shaft is fixed to the head in the case of the item (b), the relative position of the shaft marking Sm to the head and the sleeve is accurately set.

The shaft marking Sm may be printed by ink jet. A commercially available ink-jet printer can be used.

[Method for Forming Head Marking Hm]

A method for forming the head marking Hm is not limited. One recognized by viewing can function as the head marking Hm. The head marking Hm may be two-dimensional indication or three-dimensional indication. Examples of the three-dimensional indication include a recess (including a groove), a through hole, and a projection. Examples of the three-dimensional indication include a notch formed in the hosel end surface. The three-dimensional indication may be formed by the head itself, or may be formed by an indication member attached to the head. Examples of the indication member include a seal applied on the head. Examples of the method for forming the two-dimensional indication include a method using a laser, ink-jet printing, coating, and screen printing.

Preferable examples of the method for forming the head marking Hm include a method using a laser. In the method, the head marking Hm is formed by the irradiation of the laser. For example, a commercially available laser marker may be used. The marking can be simply, correctly, and rapidly formed by the laser. The method using the laser can be easily applied also to the assembled club, for example. Therefore, the method using the laser is suitable for the following item (c).

Since the head marking Hm is applied after the shaft is fixed to the head in the case of the item (c), the relative position of the head marking Hm to the shaft and the sleeve is accurately set.

The head marking Hm may be printed by ink jet. A commercially available ink-jet printer can be used.

[Method for Forming Grip Marking Gm]

A method for forming the grip marking Gm is not limited. One recognized by viewing can function as the grip marking Gm. The grip marking Gm may be two-dimensional indication or three-dimensional indication. Examples of the three-dimensional indication include a recess (including a groove), a through hole, and a projection. Examples of the three-dimensional indication include a groove formed in a surface of the grip. Paint may be disposed in the groove. The three-dimensional indication may be formed by the grip itself, or may be formed by an indication member attached to the grip. Examples of the method for forming the two-dimensional indication include a method using a laser, ink-jet printing, coating, and screen printing.

The grip marking Gm may be formed according to the difference of the material. For example, in the grip formed of rubber, the grip marking Gm may be formed by differentiating the color of the rubber.

In respect of fitting the circumferential direction position of the grip marking Gm to the circumferential direction position of the shaft marking Sm, the following method (d) or (e) may be used.

(d) After the grip including the grip marking Gm is fixed to the shaft, the shaft marking Sm is formed.

(e) The grip including the grip marking Gm is attached to the shaft including the shaft marking Sm. In the attachment, the relative position between the grip marking Gm and the shaft marking Sm is adjusted.

In the case of the methods (d) and (e), the relative position of the shaft marking Sm to the grip marking Gm is accurately set.

[Comparison Between Markings]

The shape of the shaft marking Sm may be the same as or different from the shape of the head marking Hm. In the embodiment of FIG. 11, the shapes of the markings are different from each other. That is, in the embodiment, the head marking Hm has a star shape, and the shaft marking Sm has a rectangle shape. If the shapes of the markings are different from each other, the markings are easily discriminated. If the shapes are the same, the relative positions of the markings may be easily determined.

A shape of the shaft marking Sm may be the same as or different from a shape of the grip marking Gm. In the embodiment of FIG. 11, the shapes of the markings are the same. That is, in the embodiment, the grip marking Gm has a rectangle shape, and the shaft marking Sm also has a rectangle shape. Thus, if the markings are the same, it is easy to be understood that both the markings are markings for recognizing the circumferential direction fixed position Pv.

The axial direction length of the shaft marking Sm may be the same as or different from the axial direction length of the head marking Hm. In the embodiment of FIG. 11, these axial direction lengths are different from each other. That is, as shown in FIG. 11, an axial direction length LH of the head marking Hm is different from an axial direction length LS of the shaft marking Sm. If the length LH are different from the length LS, the markings are easily discriminated.

In the embodiment of FIG. 11, the length LS is greater than the length LH. If the circumferential direction fixed position Pv of the sleeve is changed, the circumferential direction position Ps of the shaft marking Sm moves. The length LS is greater than the length LH, and thereby the movement of the circumferential direction position Ps is easily discriminated. Therefore, the circumferential direction fixed position Pv can be easily recognized.

An axial direction length of the shaft marking Sm may be the same as or different from an axial direction length of the grip marking Gm. In the embodiment of FIG. 11, these axial direction lengths are the same. That is, as shown in FIG. 11, an axial direction length LG of the grip marking Gm is the same as the axial direction length LS. If the length LS is the same as the length LG, it is easy to be understood that both the markings are markings for recognizing the circumferential direction fixed position Pv.

The length LS may be greater than the length LG, and the length LG may be greater than the length LH. The circumferential direction position Ps of the shaft can be easily discriminated by the greater length LS. At address, a distance between the grip marking Gm and the golf player's eyes is shorter than a distance between the shaft marking Sm and the golf player's eyes. Therefore, if the length LG is excessively great, the grip marking Gm may be over-prominent at address. The length LG is set to be less than the length LS, and thereby the grip marking Gm is less likely to be excessively prominent at address.

An area of the shaft marking Sm is defined as As; an area of the head marking Hm is defined as Ah; and an area of the grip marking Gm is defined as Ag. In respect of being capable of easily determining the circumferential direction position Ps of the shaft, the area As is preferably greater than the area Ah. In the same respect, the area As may be set to be greater than the area Ag.

The color of the shaft marking Sm may be the same as the color of the head marking Hm. In this case, the relative position between the marking Sm and the marking Hm is easily discriminated. In the present application, the “same color” means that a color difference ΔE is equal to or less than 10, and more preferably equal to or less than 3.

The color difference ΔE is calculated on the basis of the following mathematical formula.

ΔE=(ΔL*)²+(Δa*)²+(Δb*)²)^1/2

In the mathematical formula, ΔL* is the difference between lightness indexes L* of a first color and a second color. In the mathematical formula, Δa* is the difference between an index a* of the first color and an index a* of the second color. In the mathematical formula, Δb* is the difference between an index b* of the first color and an index b* of the second color. L*, a*, and b* are indexes in the CIELAB color system. The indexes L*, a*, and b* are calculated by the following mathematical formulas.

L*=116(Y/Yn)^1/3−16

a*=500((X/Xn)^1/3−(Y/Yn)^1/3)

b*=200((Y/Yn)^1/3−(Z/Zn)^1/3)

In these mathematical formulas, X, Y, and Z are tristimulus values in an XYZ color system, and Xn, Yn, and Zn are tristimulus values of a perfect reflecting diffuser. The CIELAB color system is a standard specified by the International Commission on Illumination (CIE) in 1976. In Japan, the CIELAB color system is used in “JIS Z 8729”. L* is an index of lightness. a* and b* are indexes related to hue and saturation. For a*, a negative value indicates green, and a positive value indicates red. For b*, a negative value indicates blue, and a positive value indicates yellow. The measurement of the indexes is conducted by using the spectrophotometer “CM-3500d” manufactured by Konica Minolta Sensing, Inc. A light receiver is applied to the surface of the object to conduct the measurement. As a light source, “a standard light D₆₅” is used. The color temperature of the light source is 6504 k. As a spectral sensitivity, “a view angle of 2°” is used. As a hole diameter, 8 mm is used.

FIG. 12 shows a shaft marking Sm according to a modification. FIG. 12 is a developed view. In fact, twelve graduation marks of the shaft marking Sm are equally disposed in the circumferential direction of a shaft.

The shaft marking Sm includes indication showing the state of the angle adjusting function. In the embodiment, a character “N” stands for “NEUTRAL”. In the embodiment, a character “R” stands for “RIGHT”. The character “R” means that a face angle is adjusted to the rightmost position. The character “R” means that a hit ball is apt to go to the right. In the embodiment, a character “L” stands for “LEFT”. The character “L” means that the face angle is adjusted to the leftmost position. In other words, the character “L” means that the hit ball is apt to go to the left. In the embodiment, a character “NU” stands for “NEUTRAL UPRIGHT”. The character “NU” means that the face angle is neutral, and a lie angle is the maximum. The state of the angle adjusting function can be recognized based on a relative position between each of these characters and a head marking Hm.

Similarly, a grip marking Gm may include indication showing the state of the angle adjusting function. Similarly, the head marking Hm may include indication showing the state of the angle adjusting function. For example, the grip marking Gm may be indication shown in FIG. 12.

A color of the shaft marking Sm may change depending on the angle of viewing. It is preferable that, based on the change in color, a color of the shaft marking Sm viewed from the angle X of the standard address viewpoint is less prominent than a color of the shaft marking Sm viewed from the front (angle: 90 degrees). In this case, the shaft marking Sm is not prominent at address, and the circumferential direction fixed position Pv can be easily confirmed. In this respect, the following item (S1) is preferable.

(S1) If the color of the shaft marking Sm viewed from the angle X of the standard address viewpoint is defined as SR1; the color of the shaft marking Sm viewed from the front is defined as SR2; a color of the shaft around the shaft marking Sm is defined as SR3; a color difference between the color SR1 and the color SR3 is defined as ΔEa; and a color difference between the color SR2 and the color SR3 is defined as ΔEb, ΔEa is less than ΔEb. The color difference is calculated by the method mentioned above.

If the number of the circumferential direction fixed positions Pv is plural, the plurality of angles X may exist. In this case, preferably, the item (S1) is satisfied in the at least one angle X. More preferably, the item (S1) is satisfied in all the angles X.

For example, a coating material whose color changes depending on the angle of viewing is used in order to form the shaft marking Sm. Examples of the coating material include a polarization coating material. A preferable polarization coating material contains a pigment flake including a plurality of layers. Examples of the polarization coating material include “Maziora” (registered trademark) manufactured by Nippon Paint Co., Ltd.

A color of the grip marking Gm may change depending on the angle of viewing. It is preferable that, based on the change in color, a color of the grip marking Gm viewed from the angle Y of the standard address viewpoint is less prominent than a color of the grip marking Gm viewed from the front (angle: 90 degrees). In this case, the grip marking Gm is not prominent at address, and the circumferential direction fixed position Pv can be easily confirmed. In this respect, the following item (G1) is preferable.

(G1) If the color of the grip marking Gm viewed from the angle Y of the standard address viewpoint is defined as GR1; the color of the grip marking Gm viewed from the front is defined as GR2; a color of the grip around the grip marking Gm is defined as GR3; a color difference between the color GR1 and the color GR3 is defined as ΔEc; and a color difference between the color GR2 and the color GR3 is defined as ΔEd, ΔEc is less than ΔEd.

If the number of the circumferential direction fixed positions Pv is plural, the plurality of angles Y may exist. In this case, preferably, the item (G1) is satisfied in the at least one angle Y. More preferably, the item (G1) is satisfied in all the angles Y.

For example, a coating material whose color changes depending on the angle of viewing is used in order to form the grip marking Gm. Examples of the coating material include a polarization coating material. A preferable polarization coating material contains a pigment flake including a plurality of layers. Examples of the polarization coating material include “Maziora” (registered trademark) manufactured by Nippon Paint Co., Ltd.

A color of the head marking Hm may change depending on the angle of viewing. It is preferable that, based on the change in color, a color of the head marking Hm viewed from the angle Z of the standard address viewpoint is less prominent than a color of the head marking Hm viewed from the front (angle: 90 degrees). In this case, the head marking Hm is not prominent at address, and the circumferential direction fixed position Pv can be easily confirmed. In this respect, the following item (H1) is preferable.

(H1) If the color of the head marking Hm viewed from the angle Z of the standard address viewpoint is defined as HR1; the color of the head marking Hm viewed from the front is defined as HR2; a color of the head around the head marking Hm is defined as HR3; a color difference between the color HR1 and the color HR3 is defined as ΔEe; and a color difference between the color HR2 and the color HR3 is defined as ΔEf, ΔEe is less than ΔEf.

For example, a coating material whose color changes depending on the angle of viewing is used in order to form the head marking Hm. Examples of the coating material include a polarization coating material. A preferable polarization coating material contains a pigment flake including a plurality of layers. Examples of the polarization coating material include “Maziora” (registered trademark) manufactured by Nippon Paint Co., Ltd.

As described above, the shaft marking Sm preferably has a viewpoint effect. The viewpoint effect means that the visibility of the shaft marking Sm viewed from the angle of the standard address viewpoint is lower than the visibility of the shaft marking Sm viewed from the front. In the item (S1), the viewpoint effect is achieved by the color. The viewpoint effect may be achieved by a shape. For example, a circumferential direction width of the shaft marking Sm may be smaller as closer to the sleeve. Examples of the shaft marking Sm include a shaft marking Sm having a tapered shape with a tip pointing to a sleeve side.

As described above, the grip marking Gm preferably has a viewpoint effect. In the item (G1), the viewpoint effect is achieved by the color. The viewpoint effect may be achieved by a shape. For example, the circumferential direction width of the grip marking Gm may be smaller as closer to the tip 66 of the grip 60. Examples of the grip marking Gm include a grip marking Gm having a tapered shape with a tip pointing to a sleeve side.

As described above, the head marking Hm preferably has a viewpoint effect. In the item (H1), the viewpoint effect is achieved by the color. The viewpoint effect may be achieved by a shape. For example, the circumferential direction width of the head marking Hm may be smaller as closer to the sole. Examples of the head marking Hm include a head marking Hm having a tapered shape with a tip pointing to a sole side.

EXAMPLES

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.

As Examples, a golf club shown in FIG. 11 was produced.

A rubber raw material was pressurized and heated by a known method to obtain a grip molded body. The grip molded body had a grip marking groove. Paint was applied in the groove to form a grip marking Gm. As shown in FIG. 11, the grip marking Gm was a line extending toward an end of a grip from an end surface of the grip.

The same sleeve as the sleeve 8 was prepared. In the sleeve, the angle θ1 was 1.0 degree. The sleeve was fixed to a tip part of a commercially available carbon shaft. The fixation is achieved by bond using an adhesive agent. The shaft with the sleeve was obtained by the bond.

A head made of a commercially available titanium alloy was prepared. A head marking Hm was formed on the head. The head marking Hm was formed by coating. The shaft with the sleeve was fixed to the head by screw connection to obtain an assembled club. In the club, the sleeve could be fixed at a plurality of circumferential direction fixed positions (12 positions).

A shaft marking Sm was formed on the assembled golf club. The shaft marking Sm was formed by a laser. As shown in FIG. 11, the shaft marking Sm was formed at a position bordered a ferrule. The shaft marking Sm was formed while a relative position between the shaft marking Sm and the head marking Hm was confirmed. The shaft marking Sm was formed at the same circumferential direction position as the circumferential direction position of the head marking Hm. Next, a grip was attached to the golf club. The grip was attached to the golf club while a relative position between the shaft marking Sm and the grip marking Gm was confirmed. The circumferential direction position of the shaft marking Sm coincided with the circumferential direction position of the grip marking Gm.

In the club, the circumferential direction positions of the shaft marking Sm and the grip marking Gm were changed with a change in the circumferential direction fixed position of the sleeve.

FIG. 11 shows a state where the circumferential direction position of the shaft marking Sm coincides with the circumferential direction position of the head marking Hm. In this Example, a face angle and a real loft angle were neutral in the case where the circumferential direction position of the shaft marking Sm coincided with the circumferential direction position of the head marking Hm. The neutral face angle means that the face angle is a central value in an adjusting range. The neutral real loft angle means that the real loft angle is a central value in an adjusting range.

In this Example, a lie angle was the minimum value in an adjusting range in the case where the circumferential direction position of the shaft marking Sm coincided with the circumferential direction position of the head marking Hm.

Since the shaft marking Sm was formed after the club was assembled in this Example, a positional relationship between the marking Hm and the marking Sm was exact. Since the grip was attached while the relative position between the shaft marking Sm and the grip marking Gm was confirmed in this Example, a positional relationship between the marking Sm and the marking Gm was exact.

The invention described above can be applied to all golf clubs.

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

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