Patent Application
20100120556
The present application claims priorities on Japanese Patent Application No. 2008-290447 filed on Nov. 13, 2008. The whole contents of the Japanese Patent Application are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a hollow golf club head.
2. Description of the Related Art
A hollow golf club head has been known. The hollow structure increases a head volume and a moment of inertia. A so-called wood type golf club head is usually hollow. The volume of a hollow part is increased and the thickness of the head is thinned with the increase in size of the head. When the hollow part is great, a hitting sound is loud. Since the vibration of the head is great when the thickness is thin, the hitting sound is loud. The head increased in size causes a loud hitting sound.
A golf club head for obtaining a good hitting sound is disclosed. The invention considering the hitting sound is proposed. Japanese Patent Application Laid-Open No. 2006-204604 (US2006/0172818 Al) discloses a curved rib extending to a heel side edge part from a toe side edge part of a sole. Japanese Patent Application Laid-Open No. 2003-102877 discloses a rib provided on an abdominal part of an out-of-plane secondary bending vibration in a sole part.
The hollow golf club head with a great volume has a drawback that the hitting sound is excessively lowered. A higher hitting sound is preferable in order to obtain a good hitting sound. Preferably, the hitting sound is further enhanced by the rib provided on the inner surface of the head.
It is an object of the present invention to provide a golf club head capable of improving a hitting sound.
A golf club head according to a first aspect of the present invention includes: a face; a sole; a crown; and a side extending between the crown and the sole. A rib is provided on an inner surface of the head. The rib has a toe side part located on an inner surface of a side of a toe side, a sole disposing part located on an inner surface of a sole, and a heel side part located on a side of a heel side. The toe side part, the sole disposing part and the heel side part are continuously provided. The toe side part, the sole disposing part and the heel side part are linearly continuously provided. The toe side part, the sole disposing part and the heel side part are provided in a line. The head is hollow.
Preferably, a ratio (Wb/Wa) of a face-back direction distance Wb (mm) between a forefront point of the head and a point R1 belonging to the rib to a width Wa (mm) of the head is 0.25 or greater and 0.50 or less in all the points R1.
Preferably, an average height of the rib is 2 mm or greater and 6 mm or less. Preferably, an average width of the rib is 0.5 mm or greater and 1.5 mm or less.
Preferably, a ratio (Wr/Wc) of a length Wr (mm) of the rib to a length Wc (mm) of the head is equal to or greater than 0.80.
Preferably, the rib has further a crown disposing part located on the inner surface of the crown; and the crown disposing part is provided on a heel side and/or a toe side of the rib.
Preferably, a rib length Lc of the crown disposing part on the heel side is equal to or less than 10 mm; and the rib length Lc of the crown disposing part on the toe side is equal to or less than 10 mm.
Preferably, the toe side of the rib terminates at the side, and the heel side of the rib terminates at the crown.
Preferably, a root of the rib has a roundness having a curvature radius rx; and the curvature radius rx is 0.5 mm or greater and 3.0 mm or less.
Preferably, an edge of an upper surface of the rib has a roundness having a curvature radius ry; and the curvature radius ry is equal to or greater than 0.2 mm.
Preferably, a width Wa of the head is 100 mm or greater and 127 mm or less.
Preferably, a length Wc of the head is 100 mm or greater and 127 mm or less.
Preferably, a volume of the head is 400 cc or greater and 470 cc or less.
Preferably, a weight Mh of the head is 175 g or greater and 205 g or less.
Preferably, a weight Mr of the rib is 1.0 g or greater and 5.0 g or less.
Preferably, a ratio (Mr/Mh) of the weight Mr of the rib to the weight Mh of the head is 0.008 or greater and 0.025 or less.
Preferably, a maximum value of a rib height HR of the rib is 3 mm or greater and 10 mm or less.
Preferably, a primary natural frequency obtained by exciting the sole is 3000 Hz or greater and 5000 Hz or less.
Preferably, the number of the ribs is equal to or less than 2.
A golf club head according to a second aspect of the present invention includes a face, a sole, a crown and a side extending between the crown and the sole. The golf club head is hollow. A rib is provided on the inner surface of the golf club head. In the golf club head, a primary natural frequency obtained by exciting the sole is 3000 Hz or greater and 5000 Hz or less.
The present invention can attain the enhancement of the hitting sound.
Hereinafter, the present invention will be described in detail according to the preferred embodiments with appropriate references to the drawings.
As shown in
As shown in
The head 2 is constituted by bonding a face member 14, a crown member 15 and a head body 16 (see
The face member 14 constitutes the whole face 4. Furthermore, the face member 14 constitutes a part of the crown 6, a part of the sole 8 and a part of the side 10. The face member 14 is approximately dish-shaped (cup-shaped). The face member 14 may be referred to as a cup face.
The crown member 15 constitutes a part of the crown 6. The crown member 15 constitutes the central part of the crown 6.
The body 16 constitutes a part of the crown 6, a part of the sole 8, a part of the side 10 and the whole hosel 12. The body 16 has a through-hole (not shown) having a shape corresponding to the shape of the crown member 15. The crown member 15 blocks the through-hole.
As shown in
In the present application, a reference vertical plane, a face-back direction and a toe-heel direction are defined. A reference state denotes a state that the center axial line Z1 is contained in a plane P1 perpendicular to a horizontal plane H and the head is placed on the horizontal plane H at a prescribed lie angle and real loft angle. The reference vertical plane denotes the plane P1.
In the present application, the toe-heel direction is a direction of line of intersection between the reference vertical plane and the horizontal plane H.
In the present application, the face-back direction is a direction perpendicular to the toe-heel direction and parallel to the horizontal plane H.
The head 2 has an inner surface on which a rib 20 is provided. As shown in
A toe side end point tp1 of the rib 20 is an end point of the toe side part 20t. A heel side end point hp1 of the rib 20 is an end point of the heel side part 20h.
The rib 20 is continuously provided without interruption. The rib 20 is continuously provided to the end point hp1 from the end point tp1. The toe side part 20t, the sole disposing part 20s and the heel side part 20h are continuously connected. That is, the toe side part 20t, the sole disposing part 20s and the heel side part 20h are continuously provided.
The number of the ribs 20 is one. The rib 20 extends in the shape of the line. As shown in
The sole 8 vibrates at the time of hitting a ball. The vibration of the sole 8 contributes to the hitting sound. The rib 20 enhances the rigidity of the sole 8. The frequency of the hitting sound is raised by the rib 20. The rib 20 contributes to the improvement of the hitting sound.
The side 10 vibrates at the time of hitting the ball. The vibration of the side 10 contributes to the hitting sound. The rib 20 enhances the rigidity of the side 10. The frequency of the hitting sound is raised by the rib 20. The rib 20 contributes to the improvement of the hitting sound.
In the embodiment, the single rib 20 reinforces the sole 8, the side 10 of the heel side and the side 10 of the toe side. It was found that the high improving effect of the hitting sound is attained by the constitution. It is believed that the vibration of the head at the time of hitting the ball includes a vibrating form in which the central part of the sole 8 is an antinode and the side 10 is a node. It is believed that the rib 20 effectively enhances the frequency of the sound caused by the vibrating form. The rib 20 can enhance the frequency of the hitting sound effectively.
Since the single rib 20 reinforces the sole 8, the side 10 of the heel side, and the side 10 of the toe side, the improvement of the hitting sound is attained while the weight of the rib 20 is suppressed.
The width of the head is shown by numeral character Wa in
Points belonging to the rib 20 are shown by numeral character R1 in
A face-back direction distance between the forefront point e1 and the point R1 is shown by numeral number Wb in
The length of the head is shown by numeral number Wc in
The length of the rib 20 is shown by numeral character Wr in
When a ratio (Wb/Wa) is too small, the rib 20 is separated from the antinode of the vibration, and the effect of suppressing tne vibration is apt to be reduced. In light of suppressing the vibration of the sole 8 and side 10 and of raising the frequency of the hitting sound, the ratio (Wb/Wa) for all the points R1 is preferably equal to or greater than 0.25, and more preferably equal to or greater than 0.29.
When the ratio (Wb/Wa) is too great, the rib 20 is separated from the antinode of the vibration, and the effect of suppressing the vibration is apt to be reduced. In light of suppressing the vibration of the sole 8 and side 10 and of raising the frequency of the hitting sound, the ratio (Wb/Wa) for all the points R1 is preferably equal to or less than 0.50, more preferably equal to or less than 0.46, still more preferably equal to or less than 0.40, and particularly preferably equal to or less than 0.38.
The rib 20 may extend in a curved condition. Even when the rib 20 extends in the curved condition, it is preferable that the ratio (Wb/Wa) for all the points R1 satisfy the preferable range. In light of enhancing a vibration suppressing effect while suppressing the weight of the rib 20, more preferably, the rib 20 extends straightly.
The head 30 has a face 4, a crown 6, a sole 8, a side 10 and a hosel 12. The crown 6 extends toward the back of the head from the upper edge of the face 4. The sole 8 extends toward the back of the head from the lower edge of the face 4. The side 10 extends between the crown 6 and the sole 8. The side 10 extends to a heel side from a toe side via a back side. The head 30 is hollow. The head 30 is a so-called wood type golf club head.
The head 30 has an inner surface on which a rib 32 is provided. The rib 32 continuously extends to the side 10 of the heel side from the side 10 of the toe side via the sole 8.
The difference between the head 30 and the head 2 is the extending direction of the rib. The extending direction of the rib 32 is inclined relative to a toe-heel direction. In the present invention, such constitution is also possible. In all points R1 of the rib 32, a ratio (Wb/Wa) is 0.25 or greater and 0.50 or less.
Thus, the rib 36 has a heel side end extending to the crown 6. In the rib 36, the toe side part 36t, the sole disposing part 36s, the heel side part 36h and the crown disposing part 36c are continuously provided. In the present invention, such constitution is also possible. In the head 34, the crown disposing part 36c is provided on the heel side only. The crown disposing part 36c may be provided on the toe side. That is, the toe side end of the rib may extend to the crown 6. The crown disposing part 36c may be provided on the toe side and the heel side. That is, the toe and heel side ends of the rib may extend to the crown 6.
At the time of hitting a ball, the crown 6 may be compressed and deformed. A loft angle is increased due to the compressive deformation of the crown 6. When the rib located on the crown 6 is too long, the compressive deformation of the crown 6 may be excessively suppressed to reduce a launch angle. The reduction of the launch angle is apt to decrease a flight distance. When the rib located on the crown 6 is too long, the weight of the head is apt to increase. When the rib located on the crown 6 is too long, the position of center of gravity of the head is apt to be raised. The launch angle is apt to be reduced due to the high position of center of gravity. In this case, the flight distance is apt to be reduced. From these viewpoints, a length Lc of the rib on the crown 6 is preferably equal to or less than 10 mm, more preferably equal to or less than 5 mm, and still more preferably equal to or less than 3 mm. In
On the other hand, in light of the improvement of a hitting sound, it is preferable that the rib extends to the crown 6. That is, in light of the improvement of the hitting sound, it is preferable that the crown disposing part 36c is provided. The rib existing on the crown 6 can further raise the frequency of the hitting sound. When the hitting sound is emphasized, it is preferable that at least one of the toe and heel sides of the rib extends to the crown 6. In this case, it is more preferable that the toe side of the rib terminates at the side 10 and the heel side of the rib terminates at the crown 6. That is, the crown disposing part 36c is preferably provided on the heel side only. The center of gravity of the head is located closer to the heel by extending only the heel side to the crown 6. The head is likely to be closed at the time of impact by locating the center of gravity of the head closer to the heel, and thereby slice can be suppressed, and hitting directivity can be stabilized.
Cracks may be generated in the rib by repeated hitting. As shown in an enlarged view of
As shown in the enlarged view of
The width Wa of the head is not limited. In light of deepening a depth of center of gravity and of increasing a moment of inertia, the width Wa of the head is preferably equal to or greater than 100 mm, more preferably equal to or greater than 107 mm, and still more preferably equal to or greater than 115 mm. In light of observance of the rules for the golf club, the width Wa of the head is preferably equal to or less than 127 mm, and particularly preferably 125 mm when the error of measurement of 2 mm is considered.
The length Wc of the head is not limited. In light of widening the face and of increasing the moment of inertia, the length Wc of the head is preferably equal to or greater than 100 mm, more preferably equal to or greater than 107 mm, and still more preferably equal to or greater than 115 mm. In light of observance of the rules for the golf club, the length Wc of the head is preferably equal to or less than 127 mm, and particularly preferably 125 mm when the error of measurement of 2 mm is considered.
The volume of the head is not limited. In light of the increase of the moment of inertia and of the enlargement of an sweet area, the volume of the head is preferably equal to or greater than 400 cc, more preferably equal to or greater than 420 cc, and still more preferably equal to or greater than 440 cc. In light of observance of the rules for the golf club, the volume of the head is preferably equal to or less than 470 cc, and particularly preferably 460 cc when the error of measurement of 10 cc is considered.
The weight Mh of the head is not limited. In light of swing balance, the weight Mh of the head is preferably equal to or greater than 175 g, more preferably equal to or greater than 180 g, and still more preferably equal to or greater than 185 g. In light of the swing balance, the weight Mh of the head is preferably equal to or less than 205 g, more preferably equal to or less than 200 g, and still more preferably equal to or less than 195 g.
The weight Mr of the rib is not limited. In light of suppressing the vibrations of the sole and side to obtain a high hitting sound, the weight Mr of the rib is preferably equal to or greater than 1.0 g, more preferably equal to or greater than 1.2 g, and still more preferably equal to or greater than 1.5 g. When the weight of the rib is excessive, the weight capable of being distributed to the head body decreases, and the moment of inertia is reduced. From this viewpoint, the weight Mr of the rib is preferably equal to or less than 5.0 g, more preferably equal to or less than 4.0 g, and still more preferably equal to or less than 3.0 g.
A ratio (Mr/Mh) of the weight Mr of the rib to the weight Mh of the head is not limited. In light of obtaining the high hitting sound, the ratio (Mr/Mh) is preferably equal to or greater than 0.008, more preferably equal to or greater than 0.009, and still more preferably equal to or greater than 0.010. When the weight of the rib is excessive, the weight capable of being distributed to the head body decreases, and the moment of inertia is reduced. From this viewpoint, the ratio (Mr/Mh) is preferably equal to or less than 0.025, more preferably equal to or less than 0.020, and still more preferably equal to or less than 0.015.
The height of the rib is shown by a double-pointed arrow HR in an enlarged view of
In light of enhancing the hitting sound, the maximum value of the height HR of the rib is preferably equal to or greater than 3 mm, more preferably equal to or greater than 3.5 mm, and still more preferably equal to or greater than 4 mm. In light of suppressing the weight of the rib, the maximum value of the height HR of the rib is preferably equal to or less than 10 mm, more preferably equal to or less than 9 mm, and still more preferably equal to or less than 8 mm.
In light of enhancing the hitting sound, the average value of the height HR of the rib on the sole is preferably equal to or greater than 3 mm, more preferably equal to or greater than 3.5 mm, and still more preferably equal to or greater than 4 mm. In light of suppressing the weight of the rib, the average value of the height HR of the rib on the sole is preferably equal to or less than 7 mm, more preferably equal to or less than 6 mm, and still more preferably equal to or less than 5 mm.
In light of suppressing the weight of the rib while suppressing the vibration of the side on the heel side, preferably, the height HR of the rib in the heel side end part of the rib is gradually or stepwisely reduced toward the heel side. In light of suppressing the weight of the rib while suppressing the vibration of the side on the toe side, preferably, the height HR of the rib in the toe side end part of the rib is gradually or stepwisely reduced toward the toe side.
In light of suppressing the weight of the rib while suppressing the vibration of the side, the average value of the height HR of the rib on the side is preferably smaller than the average value of the height HR of the rib on the sole.
The width of the rib is shown by a double-pointed arrow BR in the enlarged view of
The ratio (Wr/Wc) of the length Wr of the rib to the length Wc of the head is not limited. In light of enhancing the effect caused by the rib, the ratio (Wr/Wc) is preferably equal to or greater than 0.80, more preferably equal to or greater than 0.85, and still more preferably equal to or greater than 0.90. It is difficult to set the ratio (Wr/Wc) to 1. From this viewpoint, the ratio (Wr/Wc) is preferably equal to or less than 0.98, and more preferably equal to or less than 0.95.
“A primary natural frequency” obtained by exciting the sole is not limited. The hitting sound is connected with the vibrations of the sole or side. The primary natural frequency correlates with the hitting sound.
When the primary natural frequency is high, the hitting sound in actual hitting also is likely to be raised. From this viewpoint, the primary natural frequency is preferably equal to or greater than 3000 Hz, more preferably equal to or greater than 3400 Hz, and still more preferably equal to or greater than 3500 Hz. When the primary natural frequency is too high, resilience performance may be reduced, and there is limit on the design of the head. From these viewpoints, the primary natural frequency can be also set to 5000 Hz or less, and further 4000 Hz or less. The measuring method of the primary natural frequency is described later.
The number of the ribs is not limited. In light of suppressing the weight of the rib, the number of the ribs leading to the side of the heel side from the side of the toe side via the sole is preferably equal to or less than 2, and particularly preferably 1. In addition to the rib leading to the side of the heel side from the side of the toe side via the sole, the other rib may be provided. The rib leading to the side of the heel side from the side of the toe side via the sole may be connected to the other rib. In light of suppressing the weight of the rib, it is also preferable that a rib other than the rib leading to the side of the heel side from the side of the toe side via the sole is not provided on the sole and the side.
An angle (degree) between the extending direction of the projection image Tr of the rib and the toe-heel direction is shown by a double-pointed arrow θ1 in
The material for the head is not limited. As the material of the head, metal and CFRP (Carbon Fiber Reinforced Plastic) or the like are exemplified. As the metal used for the head, one or more kinds of metals selected from pure titanium, a titanium alloy, stainless steel, maraging steel, an aluminium alloy, a magnesium alloy and a tungsten-nickel alloy are exemplified. SUS630 and SUS304 are exemplified as stainless steel. As the specific example of stainless steel, CUSTOM450 (manufactured by Carpenter Company) is exemplified. As the titanium alloy, 6-4 titanium (Ti-6A1-4V) and Ti-15V-3Cr-3Sn-3A1 or the like are exemplified. When the volume of the head is great, the hitting sound is likely to be increased. The present invention is particularly effective in a head having a great hitting sound. From this viewpoint, the material of the head is preferably the titanium alloy. From this viewpoint, the materials of the sole and side are preferably the titanium alloy.
A method for manufacturing the head is not limited. Usually, a hollow head is manufactured by bonding two or more members. A method for manufacturing the members constituting the head is not limited. As the method, casting, forging and press forming are exemplified.
Examples of the structures of the heads include a two-piece structure in which two members integrally formed respectively are bonded, a three-piece structure in which three members integrally formed respectively are bonded, and a four-piece structure in which four members integrally formed respectively are bonded.
The form of the rib is not limited in the present invention. That is, in the present invention, the shape of the rib and the position of the rib or the like are not limited. The rib affects the vibration of the head. The rib affects the hitting sound. The primary natural frequency is likely to be raised by the rib. A head having the primary natural frequency of equal to or greater than 3000 Hz, further equal to or greater than 3400 Hz, and further equal to or greater than 3500 Hz is likely to be attained by providing the rib. Preferably, the rib is provided on the sole. The vibration of the sole at the time of hitting the ball affects the hitting sound. The rib provided on the sole can contribute to a high hitting sound. The rib provided on the sole contributes to the increase of the primary natural frequency. More preferably, the rib has a toe side part located on the inner surface of the side of the toe side, a sole disposing part located on the inner surface of the sole, and a heel side part located on the side of the heel side. More preferable examples of the ribs are the ribs shown in the first, second and third embodiments.
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 Examples.
First, the evaluation method will be described.
The primary natural frequency was measured in a state of a single head body. A measuring method is as follows.
When the attaching position of the acceleration pickup in the item (a) is the position of a node of the primary vibration of the sole, the primary vibration (primary local minimum value) does not appear in the item (f). Therefore, the measurement was performed with the acceleration pickup attached to some positions of the sole, and the position in which the primary vibration (primary local minimum value) appeared was searched. Measurement results in attaching the acceleration pickup to the position in which the primary vibration (primary local minimum value) appeared were adopted. A measuring machine in “an impact hammer method” described in Japanese Patent Application Laid-Open No. 2004-65570 can be used for measuring the primary natural frequency. For example, an adhesive is used for attaching the acceleration pickup to the sole.
Twenty golf players, each with 5 to 25 handicap, hit golf balls to evaluate the golf clubs. The evaluation was performed in five stages. Scale when the evaluation of a hitting sound was the highest was defined as five scores. Scale when the evaluation of the hitting sound was the lowest was defined as one score. The average value of twenty golf players' scales is shown in the following Tables 1 and 2.
A head having the same structure as that of the head 34 according to the third embodiment described above was produced. A head body thereof was obtained by casting a titanium alloy (Ti-6Al-4V). A face member was obtained by forging a round bar of “SuperTI-X51AF” (trade name) manufactured by NIPPON STEEL CORPORATION. A crown member was obtained by pressing a plate material made of a titanium alloy (Ti-15V-3Cr-3Sn-3Al). The head body and the face member were welded, and the head body and the crown member were welded. The welding was performed by laser welding. The outer surface of the head was ground to obtain the head. The weight of the head was 190 g. The volume of the head was 450 cc. The real loft angle of the head was 10 degrees.
As shown in
As shown in
A shaft and grip of the head were attached to obtain a golf club according to Example 1. The specifications and evaluation results of Example 1 are shown in the following Table 1.
A head and a golf club of each of Examples were obtained in the same manner as in Example 1 except for the specifications shown in Table 1 or 2. The specifications and evaluation results of Examples 2 to 8 are shown in the following Table 1 or 2.
A head of Comparative Example 1 is shown in
A head and a golf club of Comparative Example 2 were obtained in the same manner as in Comparative Example 1 except for the specifications shown in Table 2. The specifications and evaluation results of Comparative Example 2 are shown in the following Table 2.
A head of Comparative Example 3 is shown in
As shown in Tables 1 and 2, Examples have higher evaluation than those of Comparative Examples. Advantages of the present invention are clearly indicated by these results of evaluation.
The present invention is applicable to all types of golf clubs such as wood type heads and utility type (hybrid type) heads or the like.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-290447 | Nov 2008 | JP | national |
