Metal hollow golf club

Abstract

A male thread 75 is formed on the lower end of the outer peripheral surface 72 of a sleeve 7 inserted into an insertion hole formed in a hosel portion of a metal hollow golf club. A female thread 81 of a cap nut 8 is screwed onto the male thread 75 and the sleeve 7 is fixed in the insertion hole consisting of a large diameter circular hole 31, a step portion 32 and a small diameter circular hole 33. The cap nut is fastened to the lower end portion 35 of the hosel portion 3 via a washer 82.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the priority benefit of Japan application serial No. 2024-122099, filed on Jul. 29, 2024. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this application.TECHNICAL FIELD

[0002] The disclosure relates to a metal hollow golf club and more particularly relates to a metal hollow golf club with the upper end of the fixing portion of its club shaft disposed adjacent to the impact point (face center) golf club, causing angle of initial flight of a golf ball to be large and spin angular momentum to be decreased, thus enabling flying distance to be elongated.BACKGROUND

[0003] Such a metal hollow golf club has been proposed in which the upper end of the fixing portion of its club shaft is disposed adjacent to the impact point (face center) golf club, thereby increasing initial speed of golf ball, causing angle of initial flight of golf ball to be large and spin angular momentum to be decreased thus enabling golf ball to be driven up to a far position (Patent Document 1). With this metal hollow golf club, the upper end of the club shaft secured with adhesive is caused to be unconstrained and securing portion beneath the upper end (the upper end of adhering portion: fulcrum in connection of the shaft) is disposed adjacent to the impact point, thereby causing angle of initial flight of a golf ball to be large and spin angular momentum to be decreased thus enabling golf ball to be driven up to a far position. The golf club is constituted in such a manner that the tip end of the club shaft 6 is inserted into the sleeve 7 and fixed thereto with adhesive.

[0004] On the other hand, such a golf club has been proposed in which a sleeve screw hole 6h is formed in the lower end portion of a sleeve 5 to which a tip end portion of a shaft 4 is secured with adhesive and the shaft 4 is fixed to a head 2 screwing a bolt 6 into the sleeve screw hole 6h (Patent Document 2). Furthermore, such a golf club is also known in which a fixing male screw 36 is fixed to a tip end portion of a shaft holding cylinder 32 to which a tip end portion of the shaft 14 and the shaft 14 is fixed to a club head 12 with a fixing nut 44 screwed onto the fixing male screw 36 (Patent Document 3).PRIOR ART DOCUMENT[Patent Document 1] WO2017 / 073705 A1

[0006] [Patent Document 2] JP, Published Patent Application 2017-124092 A1

[0007] [Patent Document 3] JP, Published Patent Application 2006-334142 A1

[0008] With the securing constitution of the shaft in the metal hollow golf club disclosed in the above Patent Document 1, a fulcrum in connection of the shaft cannot be lower than the impact point in constitution even though the former can be disposed adjacent to the latter. Due to this, with the metal hollow golf club disclosed in the Patent Document 1, there is a restriction in enlarging angle of initial flight of a golf ball and also there is a restriction in causing spin angular momentum to be decreased. Further, the fixing constitution of the shaft 4 with the sleeve disclosed in the Patent Document 2 has a sleeve screw hole 6h as a female screw requiring a certain length at a lower end portion of the sleeve 5, so that a fulcrum in connection of the shaft cannot be disposed adjacent to the impact point in constitution. Furthermore, with the fixing constitution of the shaft 14 with the shaft holding cylinder 32 of the golf club disclosed in the Patent Document 3, the shaft 14 is fixed to a club head 12 with a fixing nut 44 with a fixing nut 44 screwed onto the fixing male screw 36, so that a fulcrum in connection of the shaft cannot be disposed adjacent to the impact point due to existence of the fixing male screw 36.

[0009] The disclosure provides a metal hollow golf club, with which the fulcrum in connection of the shaft can be disposed adjacent to the impact point.

[0010] The disclosure provides a metal hollow golf club, with which the fulcrum in connection of the shaft can be set to be lower than the height of the impact point.

[0011] The disclosure provides a metal hollow golf club enabling angle of initial flight of a golf ball to be large and spin angular momentum to be decreased.SUMMARY

[0012] The disclosure provides the following means to solve the above-mentioned problems.

[0013] That is, the metal hollow golf club according to the disclosure 1 comprises:

[0014] a head body provided with a face portion for hitting a golf ball,

[0015] a hosel portion formed in the head body and having an insertion hole in which a tip end portion of a club shaft is inserted to be fixed thereto, and

[0016] securing means of the club shaft equipped with a sleeve inserted into the insertion hole in the hosel portion that can secure only a tip end portion of the club shaft at an arbitrary position of in the axial direction by adhesion of the tip end portion of the club shaft with adhesive within the inner peripheral hole of the sleeve so that the club shaft is unconstrained at any position beyond the upper end of the secured portion in the tip end portion of the club shaft;

[0017] wherein the upper end portion of the secured portion is disposed at a position lower than an impact point of a golf ball by a golf player.

[0018] The metal hollow golf club according to the disclosure 2 is characterized in that, in the disclosure 2, the club shaft is unconstrained outside of the insertion hole in the hosel portion.

[0019] The metal hollow golf club according to the disclosure 3 is characterized in that, in any one of the disclosures 1 and 2, a male thread is formed on the lower end portion of the outer peripheral surface of the sleeve, and a nut having a female thread formed therein is screwed onto the male thread formed on the lower end portion of the sleeve.

[0020] The metal hollow golf club according to the disclosure 4 is characterized in that, in the disclosure 3, the nut is a cap nut in which the threaded screw hole is closed.

[0021] The metal hollow golf club according to the disclosure 5 is characterized in that, in the disclosure 4, a socket head cap screw for rotating the cap nut is formed on the cap nut.(Regarding Lie Angle θ)

[0022] The above matter “the upper end portion of the secured portion is disposed at a position lower than an impact point of a golf ball by a golf player” for the metal hollow golf club of the disclosure means one regarding to a position where a player gave impact to a golf ball, and supposed lie angleθ becomes 51° to 54° in a case where preset lie angle is 59° to 60°.

[0023] With the metal hollow golf club according to the disclosure, fulcrum in connection of the shaft can be disposed adjacent to the impact point, angle of initial flight of a golf ball can be enlarged and spin angular momentum can be decreased, thus enabling flying distance to be elongated.BRIEF DESCRIPTION OF DRAWINGS

[0024] FIG. 1 is a front view showing a club head body of a metal hollow golf club according to the first embodiment of the disclosure partially in section.

[0025] FIG. 2 is an enlarged longitudinal sectional view showing a portion near a hosel portion of the head body shown in FIG. 1.

[0026] FIG. 3 is a perspective view in disassembled state showing a portion near the hosel portion shown in FIG. 2.

[0027] FIG. 4 is a right-side view of FIG. 1.

[0028] FIG. 5 is a front view showing a club head body of a metal hollow golf club according to the second embodiment of the disclosure partially in section.

[0029] FIG. 6 is an enlarged longitudinal sectional view showing a portion near a hosel portion of the head body shown in FIG. 5.

[0030] FIG. 7 is a perspective view in disassembled state showing a portion near the hosel portion shown in FIG. 6.DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS(First Embodiment of Metal Hollow Golf Club)

[0031] The first embodiment of the disclosure will be explained referring the drawings below. FIG. 1 is a front view showing a club head body of the metal hollow golf club according to the first embodiment of the disclosure partially in section, FIG. 2 is an enlarged longitudinal sectional view showing a portion near a hosel portion of the head body shown in FIG. 1, and FIG. 3 is a perspective view in disassembled state showing a portion near the hosel portion shown in FIG. 2. The head body 1 shown in FIGS. 1 to 3 is one as an example applied for a metal wood club. The head body 1 shown in FIG. 1 is set with a lie angle supposed at a time of actual impact given by a player, not with a lie angle of 60° with which a golf club is set under Rules of Golf. Generally, a player swings a golf club from an address with the toe side raised by 14° to 16° upward than the designed lie angle (59° to 60°) of the head raised upward. However, the player does not give impact to a ball as it is. When the player swings the golf club actually, toe down phenomenon is created where toe side is lowered by 6° to 8° due to warping of the shaft, etc.

[0032] From the above reason, a supposed lie angle θ at a time when the player gave impact to a golf ball becomes 51° to 54° in a case where the designed lie angle is 59° to 60°. A face portion 2 having a hitting face of impact for applying impact to a ball on the front side, a hosel portion 3 as a shaft connecting portion on the shaft side, a crown portion 4 on the upper side and a sole portion on the bottom side to abut on ground are formed in the head body 1, and a club shaft 6 is inserted into the hosel portion 3 to be secured thereto. The face portion 2, the hosel portion 3, the crown portion 4 and the sole portion 5 are formed of titanium or titanium alloy through press forming thereof and these constituent portions are welded mutually along their edges to form an integral hollow club head body 1 in this example.

[0033] An insertion hole consisting of a large diameter circular hole 31, a step portion 32 and a small diameter circular hole 33 sequentially from upper side is formed in the hosel portion 3. A hollow cylindrical sleeve 7 made of a metal (for example aluminum) is inserted into the large diameter circular hole 31, the step portion 32 and the small diameter circular hole 33. A tip end portion (lower end portion) of a club shaft 6 is fixed to the inner peripheral hole 71 of the sleeve 7 by adhesion with adhesive of epoxy resin, etc. The diameter of the inner peripheral hole 71 of the sleeve 7 is formed to be somewhat larger than the diameter of the tip end portion of the club shaft 6, and adhesive penetrates into the gap between the inner peripheral hole 71 and the outer peripheral surface of the tip end portion of the club shaft 6 to secure the tip end portion of the club shaft 6 to the sleeve 7. A guard portion 73 is formed at the upper end of the outer peripheral surface 72 of the sleeve 7, and the outer peripheral surface of the guard portion 73 closely fits into the large diameter circular hole 31. Two male splines 74 are formed downwards from the lower end of the guard portion 73 on the outer peripheral surface 72 of the sleeve 7. The two male splines 74 are formed with a distance of 180° between them on the circular outer peripheral surface 72 of the sleeve 7. The male splines 74 are formed up to midway of the axial length of the outer peripheral surface 72 of the sleeve 7. Two female splines 34 are formed on the lower end side of the large diameter circular hole 31 with a distance of 180° between them and engaged with the male splines respectively to prevent the sleeve from rotating. Further, the lower end surfaces 741 of the male splines 74 abut on the step portion 32 to restrict downward movement of the sleeve 7.

[0034] A male thread 75 is formed on the lower end portion of the outer peripheral surface 72 of the sleeve 7. A female thread 81 of a metal cap nut 8 is screwed onto the male thread 75, thereby holding the sleeve 7 to be fixed in the insertion hole consisting of the large diameter circular hole 31, the step portion 32 and the small diameter circular hole 33. The cap nut 8 is fastened via a metal washer onto the lower end portion 35 of the hosel portion 3. A socket head cap screw 83 for rotating the cap nut 8 is formed on the cap nut 8. A wrench (not shown) adapted to the socket head cap screw 83 formed in a hexagonal shape, a star shape, a flower shape, etc., may be used. Instead of a wrench, a screw driver may be used. The cap nut 8 is favorable as the lower end of the female thread 81 is closed so that dust such as earth does not penetrate into the female thread 81 or the male thread 75. A cylindrical elastomer member 91 having rubber elasticity is inserted into the large diameter circular hole 31 and the lower end surface 912 of the elastomer member 91 abuts onto the upper end surface 76 of the sleeve 7. Further, a cylindrical ferrule 92 is attached to the elastomer member 91 on the upper side thereof with the lower end surface 922 of the ferrule 92 abutting onto the upper end surface 913 of the elastomer member 91. The elastomer member 91 and the ferrule 92 serve as cushioning materials mitigating strong load applied to the club shaft in the course of swing and impact.

[0035] Diameter of the inner peripheral hole 911 of the elastomer member 91 and diameter of the inner peripheral hole 921 of the ferrule 92 are formed to be somewhat large than the diameter of the tip end portion of the club shaft 6. Consequently, for the tip end portion of the club shaft 6, only the portion corresponding to the whole axial length of the inner peripheral hole 71 of the sleeve 7 is secured (adheres) thereto and the portion within the inner peripheral hole 911 of the elastomer member 91 and the portion within the inner peripheral hole 921 of the ferrule 92 are not secured (does not adhere) thereto. That is, the upper portion of the tip end portion of the club shaft 6 beyond the upper end of securing portion (the upper end surface 76 of the sleeve 7) is unconstrained within the hole for insertion in the hosel portion 3. Whole axial length of the inner peripheral hole 71 of the sleeve 7 is set to secure sufficient adhesion strength between the club shaft 6 and the sleeve 7 for enduring impact force. In the embodiment of the disclosure, the lower end portion 77 of the inner peripheral hole 71 of the sleeve 7 can be disposed below the lower end portion 35 of the hosel portion 3, so that the upper end of the securing portion of the tip end portion of the club shaft 6 (the upper end surface 76 of the sleeve 7) can be set to be lower than the impact point of a golf ball.

[0036] The head body 1 shown in FIG. 1 is set on a horizontal plane with a loft angle and lie angle at a time of actual impact given by a player, not with a loft angle and a lie angle preset under Rules of Golf. FIG. 4 is a right side view of FIG. 1. As shown in FIGS. 1 and 4, a horizontal line 22 passing through the point of impact 21 on the face portion 2 at a time of impact of a golf ball 63 is depicted. Further, a crosspoint 62 of the tip end of the securing portion of portion of the club shaft 6 (the upper end surface 76 of the sleeve 7) with the axis line 61 of the shaft 6 is acquired. In this, a horizontal line 23 passing through this crosspoint 62 is beneath the horizontal line 22 passing through the point of impact 21 (face center) (in a case of lie angle θ supposed as explained above). As a consequence of this, action of slackening of impact loft (increasing of loft angle: arrow A in FIG. 4) is created at a time of impact, thus enlarging angle of initial flight (arrow B in FIG. 4). Further, as spin angular momentum can be decreased due to gear effect (arrow C in FIG. 4), flying distance is elongated. As an effect of this, impact to a golf ball 63 is given with a loft angle larger than an indicated loft angle. Due to this, angle of initial flight can be enlarged, which is favorable for a golf player having a relatively slow head speed as he can carry a golf ball 63 to a long distant position.(Second Embodiment of Metal Hollow Golf Club)

[0037] The second embodiment of the disclosure will be explained referring the drawings below. FIG. 5 is a front view showing a club head body 100 of the metal hollow golf club according to the second embodiment of the disclosure partially in section, FIG. 6 is an enlarged longitudinal sectional view showing a portion near a hosel portion 3 of the head body 100 shown in FIG. 5, and FIG. 7 is a perspective view in disassembled state showing a portion near the hosel portion 3 shown in FIG. 6. Lie angle θ shown in FIG. 5 is same as the supposed lie angle (θ) at a time when a player actually gave impact in the first embodiment explained above. The metal hollow golf club in the second embodiment is of an example in which shape on the heel side of the crown portion 4 and shape of the hosel portion 3 are changed and the upper end of the securing portion in the tip end portion of the club shaft 6 is disposed on the outside of the head body 100. That is, this is a constitution in which the boundary point in connection of the club shaft 6 with the head body portion is disposed on the outside of the head body portion. As shown in FIGS. 5, 6, axial length of the large diameter circular hole 31 in the hosel portion 3 is formed to be short and total axial length of the insertion hole consisting of the large diameter circular hole 31, the step portion 32 and the small diameter circular hole 33 is formed to be short in the second embodiment.

[0038] Further, outer diameter dimension of the guard portion 73 at the upper end of the sleeve 7 inserted into the large diameter circular hole 31, the step portion 32 and the small diameter circular hole 33 is formed to be of a diameter larger than inner diameter dimension of the large diameter circular hole 31. Lower end surface 731 of the guard portion 73 abuts onto the upper end portion 36 of the hosel portion 3 to restrict downward movement of the sleeve 7. Two male splines 74 are formed downwards from the lower end surface 731 of the guard portion 73 on the outer peripheral surface 72 of the sleeve 7. The two male splines 74 are formed with a distance of 180° between them on the circular outer peripheral surface 72 of the sleeve 7. The male splines 74 are formed up to midway of the axial length of the outer peripheral surface 72 of the sleeve 7. Two female splines 34 are formed on the whole axial length of the large diameter circular hole 31 with a distance of 180° between them and engaged with the male splines 74 respectively to prevent the sleeve 7 from rotating. Further, the lower end surfaces 741 of the male splines 74 abut on the step portion 32 to restrict downward movement of the sleeve 7.

[0039] Axial length of a cylindrical elastomer member 91 having rubber elasticity is formed to be short and lower end surface 912 of the elastomer member abuts onto the upper end surface 76 of the sleeve 7. Further, a cylindrical ferrule 92 is attached to the elastomer member 91 on the upper side thereof with the lower end surface 922 of the ferrule 92 abutting onto the upper end surface 913 of the elastomer member 91. The upper portion of the tip end portion of the club shaft 6 beyond the upper end of the securing portion (the upper end surface 76 of the sleeve 7) is disposed outside of the head body 100. With the second Embodiment of the disclosure, the lower end portion 77 of the inner peripheral hole 71 of the sleeve 7 can be disposed below the lower end portion 35 of the hosel portion 3, so that the upper end of the securing portion of the tip end portion of the club shaft 6 (the upper end surface 76 of the sleeve 7) can be brought near to a level below the impact point 21 of a golf ball.(Trial Hitting Test)

[0040] Performance evaluation was conducted for comparing the metal hollow golf club fabricated according to the above Second Embodiment with prior golf clubs. Table 1 shows result of conducted trial hitting test.TABLE 1Result of trial hitting testClubActualAngle ofLength ofloftFlyinginitialInitialMaximumClubangleCTdistanceH / SBackspinflightspeedheightUnitinch(60 degmethod)degμsy (yard)m / secrpmdegm / secmEmbodiment45.7510.5245.0264.043.0175013.763.024.5Comparative45.7510.5245.0254.742.6255312.363.125.1example

[0041] As the golf clubs used for the trial hitting test shown in Table 1, golf club of Embodiment and golf club of Comparative Example are drivers as metal hollow golf clubs that are of same material, club length, loft angle and CT. In this, CT is a contact time when a metal ball swinging like a pendulum is caused to collide with the club face and its substantial upper limit in Rule is up to 257 μs. As the golf club of Comparative Example, a driver with a trade name “EF-02D” (sold by Epon Golf Co. Ltd. (Main Company in Niigata, Japan)) was used. The golf club of Embodiment is one in which upper portion of the tip end portion of the club shaft is caused to be unconstrained within the hole for insertion in the hosel portion as in the Embodiment explained above. In manner of the test, a person conducted actual hitting test. Trial hitting was conducted 5 times for each case, and averaged values of obtained data thereof are shown in Table 1. Measurement of flying distance, head speed (H / S), etc., in Table 1 was conducted with Trackman 4 (Registered Trade Mark). It was confirmed that, with the driver club of Embodiment used for trial hitting test, flying distance is elongated, backspin angular momentum becomes decreased and angle of initial flight becomes large.

Examples

first embodiment

(First Embodiment of Metal Hollow Golf Club)

[0031]The first embodiment of the disclosure will be explained referring the drawings below. FIG. 1 is a front view showing a club head body of the metal hollow golf club according to the first embodiment of the disclosure partially in section, FIG. 2 is an enlarged longitudinal sectional view showing a portion near a hosel portion of the head body shown in FIG. 1, and FIG. 3 is a perspective view in disassembled state showing a portion near the hosel portion shown in FIG. 2. The head body 1 shown in FIGS. 1 to 3 is one as an example applied for a metal wood club. The head body 1 shown in FIG. 1 is set with a lie angle supposed at a time of actual impact given by a player, not with a lie angle of 60° with which a golf club is set under Rules of Golf. Generally, a player swings a golf club from an address with the toe side raised by 14° to 16° upward than the designed lie angle (59° to 60°) of the head raised upward. However, the player doe...

second embodiment

(Second Embodiment of Metal Hollow Golf Club)

[0037]The second embodiment of the disclosure will be explained referring the drawings below. FIG. 5 is a front view showing a club head body 100 of the metal hollow golf club according to the second embodiment of the disclosure partially in section, FIG. 6 is an enlarged longitudinal sectional view showing a portion near a hosel portion 3 of the head body 100 shown in FIG. 5, and FIG. 7 is a perspective view in disassembled state showing a portion near the hosel portion 3 shown in FIG. 6. Lie angle θ shown in FIG. 5 is same as the supposed lie angle (θ) at a time when a player actually gave impact in the first embodiment explained above. The metal hollow golf club in the second embodiment is of an example in which shape on the heel side of the crown portion 4 and shape of the hosel portion 3 are changed and the upper end of the securing portion in the tip end portion of the club shaft 6 is disposed on the outside of the head body 100. Th...

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the priority benefit of Japan application serial No. 2024-122099, filed on Jul. 29, 2024. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this application.TECHNICAL FIELD

[0002] The disclosure relates to a metal hollow golf club and more particularly relates to a metal hollow golf club with the upper end of the fixing portion of its club shaft disposed adjacent to the impact point (face center) golf club, causing angle of initial flight of a golf ball to be large and spin angular momentum to be decreased, thus enabling flying distance to be elongated.BACKGROUND

[0003] Such a metal hollow golf club has been proposed in which the upper end of the fixing portion of its club shaft is disposed adjacent to the impact point (face center) golf club, thereby increasing initial speed of golf ball, causing angle of initial flight of golf ball to be large and spin angular momentum to be decreased thus enabling golf ball to be driven up to a far position (Patent Document 1). With this metal hollow golf club, the upper end of the club shaft secured with adhesive is caused to be unconstrained and securing portion beneath the upper end (the upper end of adhering portion: fulcrum in connection of the shaft) is disposed adjacent to the impact point, thereby causing angle of initial flight of a golf ball to be large and spin angular momentum to be decreased thus enabling golf ball to be driven up to a far position. The golf club is constituted in such a manner that the tip end of the club shaft 6 is inserted into the sleeve 7 and fixed thereto with adhesive.

[0004] On the other hand, such a golf club has been proposed in which a sleeve screw hole 6h is formed in the lower end portion of a sleeve 5 to which a tip end portion of a shaft 4 is secured with adhesive and the shaft 4 is fixed to a head 2 screwing a bolt 6 into the sleeve screw hole 6h (Patent Document 2). Furthermore, such a golf club is also known in which a fixing male screw 36 is fixed to a tip end portion of a shaft holding cylinder 32 to which a tip end portion of the shaft 14 and the shaft 14 is fixed to a club head 12 with a fixing nut 44 screwed onto the fixing male screw 36 (Patent Document 3).PRIOR ART DOCUMENT[Patent Document 1] WO2017 / 073705 A1

[0006] [Patent Document 2] JP, Published Patent Application 2017-124092 A1

[0007] [Patent Document 3] JP, Published Patent Application 2006-334142 A1

[0008] With the securing constitution of the shaft in the metal hollow golf club disclosed in the above Patent Document 1, a fulcrum in connection of the shaft cannot be lower than the impact point in constitution even though the former can be disposed adjacent to the latter. Due to this, with the metal hollow golf club disclosed in the Patent Document 1, there is a restriction in enlarging angle of initial flight of a golf ball and also there is a restriction in causing spin angular momentum to be decreased. Further, the fixing constitution of the shaft 4 with the sleeve disclosed in the Patent Document 2 has a sleeve screw hole 6h as a female screw requiring a certain length at a lower end portion of the sleeve 5, so that a fulcrum in connection of the shaft cannot be disposed adjacent to the impact point in constitution. Furthermore, with the fixing constitution of the shaft 14 with the shaft holding cylinder 32 of the golf club disclosed in the Patent Document 3, the shaft 14 is fixed to a club head 12 with a fixing nut 44 with a fixing nut 44 screwed onto the fixing male screw 36, so that a fulcrum in connection of the shaft cannot be disposed adjacent to the impact point due to existence of the fixing male screw 36.

[0009] The disclosure provides a metal hollow golf club, with which the fulcrum in connection of the shaft can be disposed adjacent to the impact point.

[0010] The disclosure provides a metal hollow golf club, with which the fulcrum in connection of the shaft can be set to be lower than the height of the impact point.

[0011] The disclosure provides a metal hollow golf club enabling angle of initial flight of a golf ball to be large and spin angular momentum to be decreased.SUMMARY

[0012] The disclosure provides the following means to solve the above-mentioned problems.

[0013] That is, the metal hollow golf club according to the disclosure 1 comprises:

[0014] a head body provided with a face portion for hitting a golf ball,

[0015] a hosel portion formed in the head body and having an insertion hole in which a tip end portion of a club shaft is inserted to be fixed thereto, and

[0016] securing means of the club shaft equipped with a sleeve inserted into the insertion hole in the hosel portion that can secure only a tip end portion of the club shaft at an arbitrary position of in the axial direction by adhesion of the tip end portion of the club shaft with adhesive within the inner peripheral hole of the sleeve so that the club shaft is unconstrained at any position beyond the upper end of the secured portion in the tip end portion of the club shaft;

[0017] wherein the upper end portion of the secured portion is disposed at a position lower than an impact point of a golf ball by a golf player.

[0018] The metal hollow golf club according to the disclosure 2 is characterized in that, in the disclosure 2, the club shaft is unconstrained outside of the insertion hole in the hosel portion.

[0019] The metal hollow golf club according to the disclosure 3 is characterized in that, in any one of the disclosures 1 and 2, a male thread is formed on the lower end portion of the outer peripheral surface of the sleeve, and a nut having a female thread formed therein is screwed onto the male thread formed on the lower end portion of the sleeve.

[0020] The metal hollow golf club according to the disclosure 4 is characterized in that, in the disclosure 3, the nut is a cap nut in which the threaded screw hole is closed.

[0021] The metal hollow golf club according to the disclosure 5 is characterized in that, in the disclosure 4, a socket head cap screw for rotating the cap nut is formed on the cap nut.(Regarding Lie Angle θ)

[0022] The above matter “the upper end portion of the secured portion is disposed at a position lower than an impact point of a golf ball by a golf player” for the metal hollow golf club of the disclosure means one regarding to a position where a player gave impact to a golf ball, and supposed lie angleθ becomes 51° to 54° in a case where preset lie angle is 59° to 60°.

[0023] With the metal hollow golf club according to the disclosure, fulcrum in connection of the shaft can be disposed adjacent to the impact point, angle of initial flight of a golf ball can be enlarged and spin angular momentum can be decreased, thus enabling flying distance to be elongated.BRIEF DESCRIPTION OF DRAWINGS

[0024] FIG. 1 is a front view showing a club head body of a metal hollow golf club according to the first embodiment of the disclosure partially in section.

[0025] FIG. 2 is an enlarged longitudinal sectional view showing a portion near a hosel portion of the head body shown in FIG. 1.

[0026] FIG. 3 is a perspective view in disassembled state showing a portion near the hosel portion shown in FIG. 2.

[0027] FIG. 4 is a right-side view of FIG. 1.

[0028] FIG. 5 is a front view showing a club head body of a metal hollow golf club according to the second embodiment of the disclosure partially in section.

[0029] FIG. 6 is an enlarged longitudinal sectional view showing a portion near a hosel portion of the head body shown in FIG. 5.

[0030] FIG. 7 is a perspective view in disassembled state showing a portion near the hosel portion shown in FIG. 6.DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS(First Embodiment of Metal Hollow Golf Club)

[0031] The first embodiment of the disclosure will be explained referring the drawings below. FIG. 1 is a front view showing a club head body of the metal hollow golf club according to the first embodiment of the disclosure partially in section, FIG. 2 is an enlarged longitudinal sectional view showing a portion near a hosel portion of the head body shown in FIG. 1, and FIG. 3 is a perspective view in disassembled state showing a portion near the hosel portion shown in FIG. 2. The head body 1 shown in FIGS. 1 to 3 is one as an example applied for a metal wood club. The head body 1 shown in FIG. 1 is set with a lie angle supposed at a time of actual impact given by a player, not with a lie angle of 60° with which a golf club is set under Rules of Golf. Generally, a player swings a golf club from an address with the toe side raised by 14° to 16° upward than the designed lie angle (59° to 60°) of the head raised upward. However, the player does not give impact to a ball as it is. When the player swings the golf club actually, toe down phenomenon is created where toe side is lowered by 6° to 8° due to warping of the shaft, etc.

[0032] From the above reason, a supposed lie angle θ at a time when the player gave impact to a golf ball becomes 51° to 54° in a case where the designed lie angle is 59° to 60°. A face portion 2 having a hitting face of impact for applying impact to a ball on the front side, a hosel portion 3 as a shaft connecting portion on the shaft side, a crown portion 4 on the upper side and a sole portion on the bottom side to abut on ground are formed in the head body 1, and a club shaft 6 is inserted into the hosel portion 3 to be secured thereto. The face portion 2, the hosel portion 3, the crown portion 4 and the sole portion 5 are formed of titanium or titanium alloy through press forming thereof and these constituent portions are welded mutually along their edges to form an integral hollow club head body 1 in this example.

[0033] An insertion hole consisting of a large diameter circular hole 31, a step portion 32 and a small diameter circular hole 33 sequentially from upper side is formed in the hosel portion 3. A hollow cylindrical sleeve 7 made of a metal (for example aluminum) is inserted into the large diameter circular hole 31, the step portion 32 and the small diameter circular hole 33. A tip end portion (lower end portion) of a club shaft 6 is fixed to the inner peripheral hole 71 of the sleeve 7 by adhesion with adhesive of epoxy resin, etc. The diameter of the inner peripheral hole 71 of the sleeve 7 is formed to be somewhat larger than the diameter of the tip end portion of the club shaft 6, and adhesive penetrates into the gap between the inner peripheral hole 71 and the outer peripheral surface of the tip end portion of the club shaft 6 to secure the tip end portion of the club shaft 6 to the sleeve 7. A guard portion 73 is formed at the upper end of the outer peripheral surface 72 of the sleeve 7, and the outer peripheral surface of the guard portion 73 closely fits into the large diameter circular hole 31. Two male splines 74 are formed downwards from the lower end of the guard portion 73 on the outer peripheral surface 72 of the sleeve 7. The two male splines 74 are formed with a distance of 180° between them on the circular outer peripheral surface 72 of the sleeve 7. The male splines 74 are formed up to midway of the axial length of the outer peripheral surface 72 of the sleeve 7. Two female splines 34 are formed on the lower end side of the large diameter circular hole 31 with a distance of 180° between them and engaged with the male splines respectively to prevent the sleeve from rotating. Further, the lower end surfaces 741 of the male splines 74 abut on the step portion 32 to restrict downward movement of the sleeve 7.

[0034] A male thread 75 is formed on the lower end portion of the outer peripheral surface 72 of the sleeve 7. A female thread 81 of a metal cap nut 8 is screwed onto the male thread 75, thereby holding the sleeve 7 to be fixed in the insertion hole consisting of the large diameter circular hole 31, the step portion 32 and the small diameter circular hole 33. The cap nut 8 is fastened via a metal washer onto the lower end portion 35 of the hosel portion 3. A socket head cap screw 83 for rotating the cap nut 8 is formed on the cap nut 8. A wrench (not shown) adapted to the socket head cap screw 83 formed in a hexagonal shape, a star shape, a flower shape, etc., may be used. Instead of a wrench, a screw driver may be used. The cap nut 8 is favorable as the lower end of the female thread 81 is closed so that dust such as earth does not penetrate into the female thread 81 or the male thread 75. A cylindrical elastomer member 91 having rubber elasticity is inserted into the large diameter circular hole 31 and the lower end surface 912 of the elastomer member 91 abuts onto the upper end surface 76 of the sleeve 7. Further, a cylindrical ferrule 92 is attached to the elastomer member 91 on the upper side thereof with the lower end surface 922 of the ferrule 92 abutting onto the upper end surface 913 of the elastomer member 91. The elastomer member 91 and the ferrule 92 serve as cushioning materials mitigating strong load applied to the club shaft in the course of swing and impact.

[0035] Diameter of the inner peripheral hole 911 of the elastomer member 91 and diameter of the inner peripheral hole 921 of the ferrule 92 are formed to be somewhat large than the diameter of the tip end portion of the club shaft 6. Consequently, for the tip end portion of the club shaft 6, only the portion corresponding to the whole axial length of the inner peripheral hole 71 of the sleeve 7 is secured (adheres) thereto and the portion within the inner peripheral hole 911 of the elastomer member 91 and the portion within the inner peripheral hole 921 of the ferrule 92 are not secured (does not adhere) thereto. That is, the upper portion of the tip end portion of the club shaft 6 beyond the upper end of securing portion (the upper end surface 76 of the sleeve 7) is unconstrained within the hole for insertion in the hosel portion 3. Whole axial length of the inner peripheral hole 71 of the sleeve 7 is set to secure sufficient adhesion strength between the club shaft 6 and the sleeve 7 for enduring impact force. In the embodiment of the disclosure, the lower end portion 77 of the inner peripheral hole 71 of the sleeve 7 can be disposed below the lower end portion 35 of the hosel portion 3, so that the upper end of the securing portion of the tip end portion of the club shaft 6 (the upper end surface 76 of the sleeve 7) can be set to be lower than the impact point of a golf ball.

[0036] The head body 1 shown in FIG. 1 is set on a horizontal plane with a loft angle and lie angle at a time of actual impact given by a player, not with a loft angle and a lie angle preset under Rules of Golf. FIG. 4 is a right side view of FIG. 1. As shown in FIGS. 1 and 4, a horizontal line 22 passing through the point of impact 21 on the face portion 2 at a time of impact of a golf ball 63 is depicted. Further, a crosspoint 62 of the tip end of the securing portion of portion of the club shaft 6 (the upper end surface 76 of the sleeve 7) with the axis line 61 of the shaft 6 is acquired. In this, a horizontal line 23 passing through this crosspoint 62 is beneath the horizontal line 22 passing through the point of impact 21 (face center) (in a case of lie angle θ supposed as explained above). As a consequence of this, action of slackening of impact loft (increasing of loft angle: arrow A in FIG. 4) is created at a time of impact, thus enlarging angle of initial flight (arrow B in FIG. 4). Further, as spin angular momentum can be decreased due to gear effect (arrow C in FIG. 4), flying distance is elongated. As an effect of this, impact to a golf ball 63 is given with a loft angle larger than an indicated loft angle. Due to this, angle of initial flight can be enlarged, which is favorable for a golf player having a relatively slow head speed as he can carry a golf ball 63 to a long distant position.(Second Embodiment of Metal Hollow Golf Club)

[0037] The second embodiment of the disclosure will be explained referring the drawings below. FIG. 5 is a front view showing a club head body 100 of the metal hollow golf club according to the second embodiment of the disclosure partially in section, FIG. 6 is an enlarged longitudinal sectional view showing a portion near a hosel portion 3 of the head body 100 shown in FIG. 5, and FIG. 7 is a perspective view in disassembled state showing a portion near the hosel portion 3 shown in FIG. 6. Lie angle θ shown in FIG. 5 is same as the supposed lie angle (θ) at a time when a player actually gave impact in the first embodiment explained above. The metal hollow golf club in the second embodiment is of an example in which shape on the heel side of the crown portion 4 and shape of the hosel portion 3 are changed and the upper end of the securing portion in the tip end portion of the club shaft 6 is disposed on the outside of the head body 100. That is, this is a constitution in which the boundary point in connection of the club shaft 6 with the head body portion is disposed on the outside of the head body portion. As shown in FIGS. 5, 6, axial length of the large diameter circular hole 31 in the hosel portion 3 is formed to be short and total axial length of the insertion hole consisting of the large diameter circular hole 31, the step portion 32 and the small diameter circular hole 33 is formed to be short in the second embodiment.

[0038] Further, outer diameter dimension of the guard portion 73 at the upper end of the sleeve 7 inserted into the large diameter circular hole 31, the step portion 32 and the small diameter circular hole 33 is formed to be of a diameter larger than inner diameter dimension of the large diameter circular hole 31. Lower end surface 731 of the guard portion 73 abuts onto the upper end portion 36 of the hosel portion 3 to restrict downward movement of the sleeve 7. Two male splines 74 are formed downwards from the lower end surface 731 of the guard portion 73 on the outer peripheral surface 72 of the sleeve 7. The two male splines 74 are formed with a distance of 180° between them on the circular outer peripheral surface 72 of the sleeve 7. The male splines 74 are formed up to midway of the axial length of the outer peripheral surface 72 of the sleeve 7. Two female splines 34 are formed on the whole axial length of the large diameter circular hole 31 with a distance of 180° between them and engaged with the male splines 74 respectively to prevent the sleeve 7 from rotating. Further, the lower end surfaces 741 of the male splines 74 abut on the step portion 32 to restrict downward movement of the sleeve 7.

[0039] Axial length of a cylindrical elastomer member 91 having rubber elasticity is formed to be short and lower end surface 912 of the elastomer member abuts onto the upper end surface 76 of the sleeve 7. Further, a cylindrical ferrule 92 is attached to the elastomer member 91 on the upper side thereof with the lower end surface 922 of the ferrule 92 abutting onto the upper end surface 913 of the elastomer member 91. The upper portion of the tip end portion of the club shaft 6 beyond the upper end of the securing portion (the upper end surface 76 of the sleeve 7) is disposed outside of the head body 100. With the second Embodiment of the disclosure, the lower end portion 77 of the inner peripheral hole 71 of the sleeve 7 can be disposed below the lower end portion 35 of the hosel portion 3, so that the upper end of the securing portion of the tip end portion of the club shaft 6 (the upper end surface 76 of the sleeve 7) can be brought near to a level below the impact point 21 of a golf ball.(Trial Hitting Test)

[0040] Performance evaluation was conducted for comparing the metal hollow golf club fabricated according to the above Second Embodiment with prior golf clubs. Table 1 shows result of conducted trial hitting test.TABLE 1Result of trial hitting testClubActualAngle ofLength ofloftFlyinginitialInitialMaximumClubangleCTdistanceH / SBackspinflightspeedheightUnitinch(60 degmethod)degμsy (yard)m / secrpmdegm / secmEmbodiment45.7510.5245.0264.043.0175013.763.024.5Comparative45.7510.5245.0254.742.6255312.363.125.1example

[0041] As the golf clubs used for the trial hitting test shown in Table 1, golf club of Embodiment and golf club of Comparative Example are drivers as metal hollow golf clubs that are of same material, club length, loft angle and CT. In this, CT is a contact time when a metal ball swinging like a pendulum is caused to collide with the club face and its substantial upper limit in Rule is up to 257 μs. As the golf club of Comparative Example, a driver with a trade name “EF-02D” (sold by Epon Golf Co. Ltd. (Main Company in Niigata, Japan)) was used. The golf club of Embodiment is one in which upper portion of the tip end portion of the club shaft is caused to be unconstrained within the hole for insertion in the hosel portion as in the Embodiment explained above. In manner of the test, a person conducted actual hitting test. Trial hitting was conducted 5 times for each case, and averaged values of obtained data thereof are shown in Table 1. Measurement of flying distance, head speed (H / S), etc., in Table 1 was conducted with Trackman 4 (Registered Trade Mark). It was confirmed that, with the driver club of Embodiment used for trial hitting test, flying distance is elongated, backspin angular momentum becomes decreased and angle of initial flight becomes large.

Examples

first embodiment

(First Embodiment of Metal Hollow Golf Club)

[0031]The first embodiment of the disclosure will be explained referring the drawings below. FIG. 1 is a front view showing a club head body of the metal hollow golf club according to the first embodiment of the disclosure partially in section, FIG. 2 is an enlarged longitudinal sectional view showing a portion near a hosel portion of the head body shown in FIG. 1, and FIG. 3 is a perspective view in disassembled state showing a portion near the hosel portion shown in FIG. 2. The head body 1 shown in FIGS. 1 to 3 is one as an example applied for a metal wood club. The head body 1 shown in FIG. 1 is set with a lie angle supposed at a time of actual impact given by a player, not with a lie angle of 60° with which a golf club is set under Rules of Golf. Generally, a player swings a golf club from an address with the toe side raised by 14° to 16° upward than the designed lie angle (59° to 60°) of the head raised upward. However, the player doe...

second embodiment

(Second Embodiment of Metal Hollow Golf Club)

[0037]The second embodiment of the disclosure will be explained referring the drawings below. FIG. 5 is a front view showing a club head body 100 of the metal hollow golf club according to the second embodiment of the disclosure partially in section, FIG. 6 is an enlarged longitudinal sectional view showing a portion near a hosel portion 3 of the head body 100 shown in FIG. 5, and FIG. 7 is a perspective view in disassembled state showing a portion near the hosel portion 3 shown in FIG. 6. Lie angle θ shown in FIG. 5 is same as the supposed lie angle (θ) at a time when a player actually gave impact in the first embodiment explained above. The metal hollow golf club in the second embodiment is of an example in which shape on the heel side of the crown portion 4 and shape of the hosel portion 3 are changed and the upper end of the securing portion in the tip end portion of the club shaft 6 is disposed on the outside of the head body 100. Th...

Claims

1. A metal hollow golf club comprising:a head body provided with a face portion for hitting a golf ball,a hosel portion formed in the head body and having an insertion hole in which a tip end portion of a club shaft is inserted to be fixed thereto, andclub shaft securing means equipped with a sleeve inserted into the insertion hole in the hosel portion that is capable of securing only the tip end portion of the club shaft at an arbitrary position in an axial direction, by adhesion of the tip end portion of the club shaft with adhesive, within an inner peripheral hole of the sleeve, so that the club shaft is unconstrained at any position beyond an upper end of a secured portion in the tip end portion of the club shaft;wherein an upper end portion of the secured portion is disposed at a position lower than an impact point of a golf ball by a golf player.

2. The metal hollow golf club according to claim 1,wherein the club shaft is unconstrained outside of the insertion hole in the hosel portion.

3. The metal hollow golf club according to claim 1, comprising:a male thread, formed on an outer periphery of a lower end portion of the sleeve; anda nut, screwed onto the male thread to fix the sleeve to the insertion hole.

4. The metal hollow golf club according to claim 3,wherein the nut is a cap nut in which a screw hole is closed.

5. The metal hollow golf club according to claim 4,wherein a socket head cap screw for rotating the cap nut is formed on the cap nut.

6. The metal hollow golf club according to claim 2, comprising:a male thread, formed on an outer periphery of a lower end portion of the sleeve; anda nut, screwed onto the male thread to fix the sleeve to the insertion hole.

7. The metal hollow golf club according to claim 6,wherein the nut is a cap nut in which a screw hole is closed.

8. The metal hollow golf club according to claim 7,wherein a socket head cap screw for rotating the cap nut is formed on the cap nut.

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