US20090137338A1

US20090137338A1 - Wood-type golf club head

Info

Publication number: US20090137338A1
Application number: US12/212,223
Authority: US
Inventors: Ryota Kajita
Original assignee: Bridgestone Sports Co Ltd
Current assignee: Bridgestone Sports Co Ltd
Priority date: 2007-11-27
Filing date: 2008-09-17
Publication date: 2009-05-28

Abstract

According to one embodiment, a wood-type golf club head includes: a face portion; a sole portion; a crown portion; a leading edge defined between the face portion and the sole portion; an upper edge defined between the face portion and the crown portion; wherein, at a basic state that the golf club head is set on a horizontal plane, a contact point between the horizontal plane and the sole portion is defined as a ground point, wherein a plane passing through the ground point and extending in a direction of a target line is defined as a vertical plane, wherein a height from the horizontal plane to a first intersection point where the face upper edge intersects the vertical plane is defined as a face height H1, and wherein a height H3 from the horizontal plane to a second intersection point where the vertical plane intersects the leading edge is defined in a range between ⅓ and ½ of the face height H1.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2008-124280, filed May 12, 2008, and Japanese Patent Application No. 2007-305227, filed Nov. 27, 2007, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a wood-type golf club head. In particular, the present invention relates to a golf club head for promoting, as a driver head, the increase in flight distance.
Flight distance in golf is determined by a ball initial velocity, a launch angle and a spin rate. In general, the higher the ball initial velocity, the greater the flight distance, and there exist a launch angle and a spin rate which make the most of the ball initial velocity. On the other hand, the current golf ball development aims at improvement of ball initial velocity and lower spin (reduction in spin rate) in order to obtain longer flight. More specifically, it is said that, current balls have spin rates too high to hit a long ball, and it is also said that a combination of current golf club and golf ball does not realize a launch angle and a spin rate which make the most of a ball initial velocity.
As one of golf club design techniques concerning flight, there is a technique for optimizing a launch angle and a spin rate by utilizing gear effect resulting from the specialty of a wood-type golf club head, which has a deep center of gravity. The launch angle and spin rate at each position on a hitting plane (face) are determined by a loft angle at this point (each position); however, in the face design of a wood club head, a loft angle at each point of the face is determined so as to provide the launch angle and spin rate at which the flight distance is maximized, and then, upon connecting each point of the face vertically so that the determined loft angle at each point of the face becomes tangential, a curve is formed longitudinally, which is a roll design. In other words, this technique is a face roll design technique provided in consideration of impact factors such as the center of gravity and moments of inertia. Further, in a head of a wood-type golf club, having a deep center of gravity, a position at which the maximum flight is obtained is generally located above a perpendicular line drawn from the center of gravity of the head onto a face plane as shown in FIG. 11. This is because, with the position of the perpendicular line drawn from the center of gravity of the head onto the face plane defined as a boundary, the spin in a topspin direction and the spin in a backspin direction act as gear effects at the upper side and the lower side, respectively, and the backspin at the upper side is reduced, which leads to the increase in flight.
On the other hand, in view of hitting points of golfers, most of professional and advanced golfers each apparently hit a ball with a face center at the sight of their club faces. Among them, there are some golfers who empirically know that the maximum flight point is located above the face center, but the aim of the hitting point in a stable game is hitting of the face center. Next, FIG. 12 shows the location of the position of the center of gravity on the face plane, which is the position of the perpendicular line drawn perpendicularly from the center of the gravity of the head onto the face plane, with respect to the face center. “DYG” in FIG. 12 indicates the difference between the position of the perpendicular line drawn from the center of gravity of the head onto the face plane and the face center (in units of mm), and shows that most of the positions of the center of gravity on the face are located 4 to 8 mm above the face center, and that the greater the loft angle of the face, the greater the “DYG”. Furthermore, the relationship between the face height and the “DYG” is shown in FIG. 13, from which it can be understood that the height of the center of gravity is located 4 to 8 mm above the center of the face regardless of the face height, and that the height of the center of gravity with respect to the face height is substantially constant.
Moreover, FIG. 11 shows that the above-mentioned maximum flight distance point on the face is located above the position of the perpendicular line drawn from the center of gravity of the head onto the face plane; however, it can be assumed that the maximum flight distance point often significantly differs from the hitting point at which professional and advanced golfers aim, i.e., the face center. In other words, it can be said that the hitting with the face center, at which many professional and advanced golfers aim, induces the action of gear effect in a direction in which backspin is increased, leading to the reduction in flight distance. In order to hit a long ball, it is necessary to hit the ball with a point located above the face center. Even though professional and advanced golfers know this, the hitting point in a stable game is the face center. It is an object of the present inventor to make the hitting area of a golfer, i.e., the face center, coincide with the maximum flight distance point. To achieve this object, the position of the center of gravity of a head has to be lowered by 10 mm or more. Conventional techniques for lowering the center of gravity of a wood head include ones in which attempts are made to daringly change head shape (see JP-A-H07-178207 (Page 3, FIG. 1) and JP-A-2000-262657 (Page 2, FIG. 1)).
In a wood-type golf club head disclosed in each of JP-A-H07-178207 and JP-A-2000-262657, an intersection point of a perpendicular line from the center of gravity with respect to a face plane, i.e., a sweet spot, is to be located at the center of the face plane (face center); however, the head has an unusual shape such as a vault shape or a potbellied shape, and a golfer has felt the difficulty of coming to the ready because of the unduly peculiar shape when the golfer has seen the head from above at address.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, there is provided a golf glove including: a main body that includes a palm side portion and a back side portion, the palm side portion being configured to closely fit to a palm of a hand of a golfer, the back side portion being configured to closely fit to a back side of the hand; a first slip preventive element placed at least on a first area that is interior of a grip receiving area on an outer surface of the main body, where a grip portion of a golf club is in contact with the main body when the golfer grips the golf club; wherein the first slip preventive element has a larger slip resistance to sweat of the hand and water coming into an inside of the golf glove than the main body.
According to another aspect of the present invention, there is provided a golf glove including: a main body that includes a palm side portion and a back side portion, the palm side portion being configured to closely fit to a palm of a hand of a golfer, the back side portion being configured to closely fit to a back side of the hand; a second slip preventive element placed on a second area that is interior of an intermediate portion area in the main body, the intermediate area being positioned at a substantially intermediate between a lowermost position of a little finger portion of the main body and a wrist portion of the main body, so as to extend from the palm side portion to the back side portion; wherein the second slip preventive element is made of a porous elastic resin film.
According to another aspect of the present invention there is provided a golf glove including: a main body that includes a palm side portion and a back side portion, the palm side portion being configured to closely fit to a palm of a hand of a golfer, the back side portion being configured to closely fit to a back side of the hand; a third slip preventive element including a traversing portion and a lower portion, the traversing portion placed on an interior of the palm side portion so as to traverse bases of finger portions except thumb portion in the main body, the lower portion placed on the interior of the palm side portion so as to extend along a life line on the palm of the golfer in a direction reverse to an extending direction of the life line; wherein the third slip preventive element is made of a resin foam film.
According to another aspect of the present invention there is provided a golf glove including: a main body that includes a palm side portion and a back side portion, the palm side portion being configured to closely fit to a palm of a hand of a golfer, the back side portion being configured to closely fit to a back side of the hand, the back side portion including an access opening formed at a lower position thereof; a locking belt that is sewn to the back side, the locking belt for closing the access opening; a forth slip preventive element placed on a forth area that is interior of the back side portion, the forth area extending from a lowermost position of an index finger portion of the back side portion toward the locking belt, the forth slip preventive element including minute projections and made of an artificial leather.
In this way, the invention is characterized in that the preventive elements which exhibit the high resistance to slip relative to water secreted from the hand of the golfer and water which penetrates into the golf glove in wet weather are affixed to the specific locations on the inner surface of at least the portions on the palm side area or the back side area of the glove main body with which the grip portion of the golf club is brought into abutment, whereby the stable grip is obtainable under every condition, thereby making it possible to prevent effectively an error in hitting a ball.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other object and advantages of this invention will become more fully apparent from the following detailed description taken with the accompanying drawings in which:

FIG. 1 is a lateral view of a golf club head according to exemplary embodiment of the invention.

FIG. 2 is a front view of FIG. 1.

FIG. 3 is a lateral view showing a head lower portion rectangularly removed from a leading edge to a sole according to exemplary embodiment of the invention.

FIG. 4 is a lateral view showing a head lower portion removed so that a convex curved surface remains from a leading edge to a sole according to exemplary embodiment of the invention.

FIG. 5 is a lateral view showing a head lower portion triangularly removed from a leading edge to a sole according to exemplary embodiment of the invention.

FIG. 6 is a lateral view of a golf club head according to exemplary embodiment of the invention.

FIG. 7 is a lateral view of a golf club head according to exemplary embodiment of the invention.

FIG. 8 is lateral view of a golf club head according to exemplary embodiment of the invention.

FIG. 9 is lateral view of a golf club head according to exemplary embodiment of the invention.

FIG. 10 is front view of FIG. 9.

FIG. 11 is lateral view showing a conventional example.

FIG. 12 is graph showing the relationship between a loft angle and DYG according to exemplary embodiment of the invention.

FIG. 13 is graph showing the relationship between a face height H1 and DYG according to exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a lateral view of a head body 1, and FIG. 2 shows a front view of the head body 1, with a leading edge 3 formed to be located at a higher position compared with a normal head. In FIG. 1 and FIG. 2, there is shown a state in which the head body 1 is set on a horizontal plane B at predetermined lie angle and loft angle. When the head body 1 is set in this manner, a face center FC is set at the midpoint between an upper edge and a lower edge (leading edge 3) of a face 2, which intersect a vertical plane X (shown as an “X plane” in the diagrams) passing through a ground point A between a sole 4 and the horizontal plane B and extending from the rear of the head in a target line direction serving as a target. A height measured from this ground point A to the upper edge of the face 2 is referred to as a face height H1. Further, a height measured from the leading edge 3 to the upper edge of the face 2 is referred to as a face thickness height H2. The position of a point (midpoint), obtained by bisecting this face thickness height H2, is defined as the face center FC. A height H3 measured from the horizontal plane B to the leading edge 3 is defined as ⅓ to ½ of the face height H1. An intersection point of the face 2 and a perpendicular line, perpendicularly drawn from the center of gravity G of the head body 1 onto the plane of the face 2, is located lower than the height of the face center FC. The face center FC is defined as FC=(H1−H3)/2+H3.
The height H3 may be defined as ⅙ to ½ of the face height H1, or may be defined as ⅛ to ½ thereof. The height H3 is defined as ½ of the face height H1 at the maximum.
FIG. 3 shows an embodiment in which, in order to raise the height of the leading edge 3 from the horizontal plane B, a portion adjacent to a chamfered portion of the underlined part of the face 2 is rectangularly removed, thereby setting a maximum flight distance point at the face center FC. An effective hitting area of the face 2 becomes smaller than before.
A portion adjacent to a chamfered portion is formed into a convex curved surface shape in FIG. 4, and is triangularly removed in FIG. 5, in each of which the maximum flight distance point is set at the face center FC.
FIG. 6 shows an example in which, at a position lower than that of a sole edge line 40 of a normally shaped wood-type head, a second sole 41 is set at the rear of the head. If allowance is made for the head weight, excess weight is put to the inside/outside of the second sole 41, thereby making it possible to set the center of gravity at a low and deep position. Generally, the farther away the center of gravity from a face 2, the greater the gear effect. Accordingly, the present embodiment is effective for a golfer and/or a golf ball who and/or which achieve(s) the maximum flight distance by placing importance on a spin.
In FIG. 6, when a head body 1 is set on a horizontal plane B, a height H1 measured from the horizontal plane B tangent to the edge line of the second sole 41 to the upper edge of the face 2 on a vertical plane X (X plane), a height H3 measured from the horizontal plane B to a leading edge 3, and a face thickness height H2 are similar to those of FIG. 1. In this embodiment, a height H4 measured from the horizontal plane B to the sole edge line 40, and a height H5 of a chamfered surface H5 are provided so that the height H4 is 5 to 20 mm and the height H5 is 2 to 5 mm.
FIG. 7 shows an example in which, at a position lower than that of a sole edge line 40 of a normally shaped wood-type head, a second sole 41 is set at the front of the head. If allowance is made for the head weight, excess weight is put to the inside/outside of the second sole 41, thereby making it possible to set the center of gravity at a low and deep position. Generally, the closer the center of gravity to a face 2, the smaller the gear effect. Accordingly, the present embodiment is effective for a golfer and/or a golf ball who and/or which achieve(s) the maximum flight distance by placing importance on a ball initial velocity.
FIG. 8 shows an example in which, at a position lower than that of a sole edge line 40 of a normally shaped wood-type head, a second sole 41 is set in the entire range including the front and rear of the head. If allowance is made for the head weight, excess weight is concentrated at or dispersedly put at the inside/outside of the second sole 41, thereby making it possible to set the center of gravity at any position, and to set the moment of inertia of the head related to the vertical stability of a trajectory at any value.
FIG. 9 and FIG. 10 each show an example in which, at a position lower than that of a sole edge line 40 of a normally shaped wood-type head, a plurality of second soles 41 having different heights are set at the front and rear of the head. If allowance is made for the head weight, excess weight is put at the inside/outside of the second soles 41, thereby making it possible to set the center of gravity at any position, and to set the moment of inertia of the head related to the vertical stability of a trajectory at any value.
Each of the embodiments shown in FIG. 6 to FIG. 10 is based on the following findings. Specifically, if a general chamfer height H3 of a general wood-type head is 1 to 2 mm, the chamfer height must be further raised at least twice as high by 8 to 16 mm. In other words, the height H3 is located at a height of 9 to 18 mm in order to make the center (height) of the face 2 coincide with the position of the center of gravity on the plane of the face 2. Further, a large number of dimples are disposed in a golf ball. This ball is hit with the face plane of a golf club head, and the face plane has a loft angle so that it faces upward normally at an angle of 7 degrees to 60 degrees (in the case of a wood club head, the loft angle is about 7 degrees to about 15 degrees). Therefore, the ball hit with the face plane flies with backspin. The golf ball with backspin can fly while obtaining a lift force resulting from the effect of the dimples due to rotation. In order to obtain this lift force, it is effective to hit the ball with the face plane at a position thereon located higher than the center of gravity. Hence, from the above description, the height H3 is preferably located at a height of at least 10 to 20 mm. This height is located at ⅙ to ½ of the face center height in a large hollow golf club head. The large hollow head mentioned herein is generally called a “driver head”, and refers to a head having a head volume of 300 cc or more, preferably 350 cc to 500 cc. Furthermore, a weight material, having a specific gravity greater than that of the head body, is placed onto a sole plane of the hollow head, thereby making it possible to lower the position of the center of gravity. In this case, the chamfer height is allowed to a position of ⅛ of the face height, and can thus be designed to be located at a position of ⅛ to ½ of the face height, including the head of a fairway wood. In this case, when the head body 1 is formed by a titanium alloy, the weight material is preferably a material such as a copper alloy or a tungsten alloy. At least 10 g or more, preferably 20 g to 50 g, of the weight material may be placed. Moreover, in order to adjust the position of the center of gravity, the weight material may be placed at a back portion, or at the boundary between a sole portion and the back portion. Besides, when the position of the center of gravity is located at the heel side, the toe side of the face may be increased in thickness, or the weight material may be additionally placed, thus making it possible to longitudinally adjust the position of the center of gravity.
In general, if a titanium alloy head is designed to have a head volume of 300 cc or more and a face thickness of 3 mm or less, such a design runs counter to the SLE (Spring Like Effect) rule. However, when the chamfer height is raised and the width of the face is reduced in this manner, it becomes difficult for the face to cause deflection, and it is unnecessary to provide a special structure, thus making the cost reasonable. Moreover, until now, the position at which a ball flies farthest (which is located above a sweet spot), and the position of the center of gravity of the face, or the most deflective position of the face have been greatly deviated from each other; however, the adoption of the present method can fly the ball more efficiently. Furthermore, the present invention is implemented as a hollow metal golf club head in which, in particular, a titanium alloy, an aluminum alloy or the like is used as a metal material, and a crown portion and a sole portion each have a thickness of 0.5 mm to 2 mm, preferably 0.7 mm to 1.2 mm. The sole portion has a generally uniform large round, and the round measures about 80 mm to about 125 mm from the toe side to the heel side. On the other hand, in the case of a raised sole, the raised part is solid, and the lowermost portion thereof is preferably formed by a material having a specific gravity greater than that of the head body.
As described with reference to the embodiment, there is provided a wood-type golf club head that eliminates the difficulty of coming to the ready at address, and allows a face center to serve as a maximum flight distance point.
According to the embodiment, when a head body is set on a horizontal plane, a height measured to an intersection point of a face upper edge and a vertical plane, passing through a ground point between this horizontal plane and a sole of the head body and extending from the rear of the head in a target line direction serving as a target, is defined as a face height, and a height measured to an intersection point of the vertical plane and a leading edge is defined as ⅓ to ½ of the face height; thus, if a clear face area is indicated, a professional or advanced golfer who has a high technique of stable hitting with the face center can obtain a maximum flight distance by hitting with the center of the face (face center) because he or she has the technique to hit with the center. Furthermore, when the head is seen from above at address, it has the similar shape as a conventional head, thus preventing the drawback of causing the difficulty of coming to the ready.
Moreover, in the embodiment in which, when the head body is set on the horizontal plane, there is provided an edge line of at least one second sole located 5 to 20 mm below a sole plane extending from the lowermost point of a chamfered surface in the direction opposite to the target line direction, via a plane or a convex curved surface, i.e., a so-called chamfer, extending downward from the lowermost point of the head body and in the direction opposite to the target line direction, it is possible to make the face center coincide with the maximum flight distance point, and to increase the flight distance. Besides, the head appearance has an unprecedentedly peculiar shape that attracts the attention of a bystander, but a golfer who uses this head does not feel the peculiar shape at address.

Claims

1. A wood-type golf club head comprising:

a face portion;

a sole portion;

a crown portion;

a leading edge defined between the face portion and the sole portion;

an upper edge defined between the face portion and the crown portion;

wherein, at a basic state that the golf club head is set on a horizontal plane, a contact point between the horizontal plane and the sole portion is defined as a ground point,

wherein a plane passing through the ground point and extending in a direction of a target line is defined as a vertical plane,

wherein a height from the horizontal plane to a first intersection point where the face upper edge intersects the vertical plane is defined as a face height H1, and

wherein a height H3 from the horizontal plane to a second intersection point where the vertical plane intersects the leading edge is defined in a range between ⅓ and ½ of the face height H1.

2. The wood-type golf club head according to claim 1, wherein the height H3 is defined in a range between ⅙ and ½ of the face height H1.

3. The wood-type golf club head according to claim 1, wherein the height H3 is defined in a range between ⅛ and ½ of the height H1.

4. The wood-type golf club head according to claim 1, wherein a third intersection point where the face portion intersects a perpendicular line drawn from a center of gravity of the golf club head onto the face portion is lower than a face center FC of the face portion, the face center FC being defined as

FC=(H1−H3)/2+H3.

5. The wood-type golf club head according to claim 1 further comprising a chamfer portion formed between the leading edge and the sole portion,

wherein the sole portion includes a first sole portion and a second sole portion including the ground point,

wherein a height H0 from the horizontal plane to the ground point is lower than a height H4 from the horizontal plane to a lowermost portion of the first sole portion, and

wherein the height H0 is lower than a height from the horizontal plane to a lowermost point of the chamfered portion;

6. The wood-type golf club head according to claim 5, wherein the height H4 is in a range from 5 mm to 20 mm.

7. The wood-type golf club head according to claim 5, wherein a height H5 from the leading edge to the lowermost portion of the first sole portion is in a range from 2 mm to 5 mm.

8. The wood-type golf club head according to claim 5, wherein the chamfered portion is extend downward from the leading edge and in a direction opposite to the target line direction.