JP2007136067A - Golf club - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf club facilitating the swinging despite of its long size and helpful to increasing a carry. <P>SOLUTION: This golf club has a shaft, a golf club head fixed to its tip side, and a grip provided in the rear end side of the shaft, its overall length is 46-48 inches, a swing balance is C5 to D0 by the 14-inch balance measuring method, an inertia moment of the club at the rear end of the grip is 2,850-3,000 kg×cm<SP>2</SP>, the distance of the gravity center of the golf club head is 30-35 mm, and the inertia moment of the golf club head around the center line of the shaft is 5,500-6,000 g×cm<SP>2</SP>. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a golf club, and more particularly to a golf club that is long and easy to swing, and that is useful for increasing a flight distance.

  Wood-type golf clubs such as drivers and fairway woods are required to have a flight distance capability that allows the ball to fly farther. In general, it is effective to increase the initial speed of the ball to be launched, and the means of the flying distance is, for example, improvement of the resilience performance of the head, improvement of head kinetic energy by increasing the head weight, or lengthening of the club. Is known to improve the head speed (see, for example, Patent Documents 1 and 2 below).

JP 11-99231 A JP 2004-201111 A

  However, the coefficient of restitution of the head tends to be regulated as seen in USGA and R & A. Therefore, there is a possibility that a head whose resilience performance is excessively improved cannot be used for a formal competition in the future.

  In addition, the other two methods have a drawback that it is difficult to swing the club. For example, an increase in the length of a club tends to provide the advantage of improving the head speed, but it is difficult to swing and it is difficult to control the head (face surface). For this reason, many golfers often hit the ball with the head open. As a result, the hit ball is in the right direction (hereinafter, unless otherwise specified, Slices that fly are likely to occur.

  In view of this, the inventors have attempted to make swinging easier for the elongated golf club in order to take advantage of the improvement in head speed.

  Generally, in a series of swing motions from back swing (take back) to hit (impact), there are two moments that particularly affect the ease of swing. One is the start of a backswing when moving a stationary club, and the other is the moment immediately before hitting the ball. At any moment, the vicinity of the tip of the golfer's right hand holding the grip becomes the fulcrum that supports the club, in other words, the center of the club's rotational movement. Therefore, it is considered that at these two moments, it is possible to make the swing easier by improving the operability of the club.

  Therefore, the inventors used a swing balance based on a 14-inch balance method, which represents a weight at the time of swing with a position relatively close to the right hand as a fulcrum, as a parameter for quantifying the operability of the club at the two moments. Adopted and tried to limit this.

  In the swing motion, during the period from the second half of the backswing to the start of the downswing (also referred to as “turning back”), the club rotates with the golfer's left hand position as a fulcrum. Therefore, in order to improve the ease of swinging the club, it is necessary to improve the operability of the club with the left hand position of the golfer holding the grip as a fulcrum in addition to the above improvement. In the present invention, as a parameter for quantifying the operability of the club during these exercises, the moment of inertia of the club at the rear end of the grip relatively close to the left hand is adopted and an attempt was made to limit it. .

  Further, in a golf club having a long length, when the ball is hit, the golf club head often fails to return to the addressed state and hits with the face open. Therefore, in order to take advantage of the lengthening of the club, it is necessary to improve the motion characteristics of such a head.

  In addition to simultaneously satisfying the above two parameters, that is, the swing balance by the 14-inch balance measurement method and the preferable range of the moment of inertia of the club at the rear end of the grip, the center of gravity distance and the moment of inertia of the golf club head are satisfied. It is an object to provide a golf club that can fly a ball to a farther distance by making it easy to swing while being long, and to easily return to the position that the head has addressed, based on what is prescribed. It is said.

The invention according to claim 1 of the present invention is a golf club having a shaft, a golf club head fixed to the front end side thereof, and a grip provided on the rear end side of the shaft, wherein the total length of the club is 46-48 inch, 14-inch balance measuring method is C5-D0, the moment of inertia of the club at the rear end of the grip is 2850-3000 kg · cm ² , the center of gravity distance of the golf club head is 30-35 mm, and the shaft The moment of inertia of the golf club head around the axial center line is 5500 to 6000 g · cm ² .

  Here, the above-mentioned “club total length” is measured based on “c. Length” in the attached rule II “1. club” in the JGA (Japan Golf Association) golf rules. Specifically, the lengths of the wood-type and iron-type clubs are measured by placing the club 1 on the horizontal plane HP as shown in FIG. To be done. The total length of the club is measured as a distance L from the intersection Y of the two surfaces HP and IP to the rear end 4e of the grip 4.

  The rear end 4e of the grip means the rearmost end of the grip 4, but when the bulge that protrudes rearward is provided at the end of the grip as shown in FIG. 1, the radius becomes the largest. The rear edge of the grip is the rear edge of the grip.

  The “swing balance” (sometimes referred to as “swing weight”) represents the weight that is felt when the club is swung, and as shown in FIG. Using the position of 14 inches from the end 4e along the shaft axis as a fulcrum, multiply the distance X (unit: inch) in the shaft axis direction from the fulcrum to the center of gravity G of the club by the total club weight (unit: ounce). It is calculated based on the numerical value (unit: inch ounce).

  The numerical value indicating the swing balance is classified into six stages A to F according to the conversion table, and indicates that the weight increases from “A” to “F”. Further, each of the sections A to F is further divided into 10 parts from 0 to 9, which means that they become heavier from “0” to “9”. The final swing balance is displayed by a symbol in which any one of the numbers 0 to 9 is added to the alphabets A to F indicating the sections, such as A0 and C6.

  In this specification, the swing balance is measured by using a 14-inch balance measuring instrument (not shown) and reading the scale indicated by the pointer. As shown schematically in FIG. 4, the measurement scale of the swing balance measuring instrument has a width between the minimum reading scales (for example, C7, C8, C9, etc.), so that the pointer j is located between the scales C7 and C8. May show. In this specification, in such a case, the swing balance having the smaller scale (in this example, C7) is employed. When the pointer j points between the scales and other than the intermediate position, the scale closer to the pointer j is read as the swing balance.

  Table 1 shows the correspondence between the symbol of the swing balance and the numerical value (inch / ounce) for reference. In the club 1 of the present invention, the numerical value (inch ounce) is generally included in the range of 204.75 to 213.5.

Further, as shown in FIG. 5, the “moment of inertia of the club at the rear end of the grip” is obtained by the inertia moment measuring device 20 (for example, INERTIA DYNAMICS Inc.) so that the axis center line CL of the shaft 2 is horizontal. The club 1 is balanced and supported on the measuring jig 21 of a measuring device (such as MODEL NUMBER RK / 005-002). At this time, the center of gravity G of the club 1 is located on the measuring jig 21. Next, the moment of inertia Ia around the center of gravity G of the club 1 (the rotation axis is Z) is measured. The moment of inertia I _G of the club at the rear end of the grip, with a parallel axis theorem, determined by calculation by the following equation.
I _G (kg · cm ² ) = Ia + m · R ²
Here, m is the mass of the club (kg), R is the axial distance (cm) from the rear end 4e of the grip 4 to the center of gravity G of the club 1, and Ia is the moment of inertia around the center of gravity G of the club 1 ( kg · cm ² ).

  Further, as shown in FIGS. 6 (A) and 6 (B), the “center of gravity distance” is obtained by arranging the axis center line CL of the shaft 2 of the golf club head 1 in an arbitrary vertical plane VP and by a prescribed line. In a reference state where the face 3a is held at a specified loft angle (real loft angle) and placed on the horizontal plane HP while being tilted at an angle α, a perpendicular line N is drawn from the center of gravity HG of the golf club head 1 to the vertical plane VP. The intersection of the perpendicular N and the vertical plane VP is defined as a projection head barycentric point VHG. The shortest distance HGL between the projection head barycentric point VHG and the axial center line CL of the shaft 2 is defined as the barycentric distance.

  The “moment of inertia of the golf club head around the axis center line of the shaft” is measured, for example, by the moment of inertia measuring instrument in a state where the shaft is removed from the golf club head. In addition, although the painting of a golf club head is included, when a cone-shaped ferrule or the like is attached to the connecting portion with the shaft, the moment of inertia is measured by removing it.

  The invention according to claim 2 is the golf club according to claim 1, wherein the total weight of the club is 285 to 300 g.

The invention according to claim 3 is the golf club according to claim 1 or 2, wherein the moment of inertia of the club at the rear end of the grip is 2900 to 2980 kg · cm ² .

  The invention according to claim 4 is the golf club according to any one of claims 1 to 3, wherein the swing balance is C6 to C9.

  A fifth aspect of the present invention is the golf club according to any one of the first to fourth aspects, wherein the weight of the golf club head is 180 to 195 g.

  The invention according to claim 6 is characterized in that a weight member having a weight of 2 to 9% of the weight of the golf club head is disposed on the rear end side of the shaft or the rear end side of the grip. The golf club according to any one of Items 1 to 5.

  The golf club of the present invention is easy to swing while being 46 to 48 inches long. Therefore, both improvement in head speed and excellent head control can be achieved. Therefore, it is possible to fly the ball accurately and further in the intended direction.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall front view of a golf club (hereinafter, simply referred to as “club”) 1 of the present embodiment. The club 1 of the present invention has a total length of 46 to 48 inches, a swing balance of C5 to D0 by a 14 inch balance measurement method, a club inertia moment of 2850 to 3000 kg · cm ² at the rear end 4e of the grip 4, and a golf club. The center-of-gravity distance of the head is 30 to 35 mm, and the moment of inertia of the golf club head around the axial center line of the shaft is 5500 to 6000 g · cm ² .

  The club 1 has a shaft 2, a golf club head (hereinafter simply referred to as “head”) 3 fixed to the tip 2 </ b> A of the shaft 2, and a head 3 from a rear end 2 </ b> B of the shaft 2. And a grip 4 that is provided in a predetermined area and is gripped by the player. The club 1 of the present embodiment is a wood type including at least a driver (# 1), a plush (# 2), a spoon (# 3), a buffy (# 4), a creek (# 5), and the like. The present invention is particularly suitable for a wood-type golf club that requires such a flight distance.

  The club 1 has a total club length of 46 to 48 inches. The head speed when hitting the ball increases in proportion to the overall length of the club. For this reason, when the total length of the club is less than 46 inches, it is not possible to sufficiently expect an improvement in the head speed for realizing a significant increase in the flight distance. On the other hand, if the total length of the club exceeds 48 inches, the operability of the club 1 is lowered and the golf rules are violated. Although not particularly limited, the total length L of the club is preferably 46.5 inches or more, and more preferably 47 inches or more.

  As shown in FIG. 1, FIG. 6, or FIG. Accordingly, the weight can be reduced. Although it does not specifically limit as said metal material, For example, one or more, such as an aluminum alloy, titanium, a titanium alloy, stainless steel, or a magnesium alloy, is preferable. The head 3 of this embodiment is composed of a titanium alloy that is entirely made of Ti-6Al-4V. At least a part of the head 3 may be made of a non-metallic material such as a fiber reinforced resin. Such an aspect is preferable in that the head 3 can be further reduced in weight.

  The head 3 includes a face portion 3a having a face surface F that forms a striking surface for hitting a ball, a crown portion 3b that is continuous with the face portion 3a and that forms the top surface of the head, and a sole portion that is continuous with the face portion 3a and forms the bottom surface of the head. 3c, a side portion 3d extending between the crown portion 3b and the sole portion 3c from the toe side edge of the face surface F through the back face to the heel side edge of the face surface F, and the heel of the crown portion 3b And a cylindrical shaft insertion portion 3e into which the distal end side of the shaft 2 is inserted.

  As shown in FIG. 7, the face portion 3a includes, for example, a central portion 3a1 having a large thickness t1, and a peripheral portion extending annularly so as to surround the central portion 3a1 and having a thickness t2 smaller than the thickness t1. 3a2. Such a face portion 3a is capable of maximizing the coefficient of restitution of the head within the range of, for example, a golf rule, because the peripheral portion 3a2 having a small thickness is greatly bent when the ball is hit. This reduces the weight of 3a and helps to reduce the weight of the head 3. The central portion 3a1 having a large thickness is useful for improving the durability of the face portion 3a.

  From the above viewpoint, the thickness t1 of the central portion 3a1 is preferably 2.7 mm or more, more preferably 2.8 mm or more, and the upper limit is preferably 3.1 mm or less, more preferably 3.0 mm or less. Is desirable. Similarly, the thickness t2 of the peripheral portion 3a2 is, for example, 1.9 mm or more, more preferably 2.0 mm or more, and the upper limit is preferably 2.5 mm or less, more preferably 2.4 mm or less. In addition, the face portion 3a is preferably provided with a thickness transition portion 3a3 between the central portion 3a1 and the peripheral portion 3a2 that smoothly changes in thickness and connects the two portions. This prevents stress concentration at the boundary between the central portion 3a1 and the peripheral portion 3a2 and helps improve durability.

  Further, the thicknesses t3 and t5 of the crown portion 3b and the side portion 3d are not particularly limited. However, if the thickness is too large, the head weight increases and the swing balance tends to be difficult to adjust, and the thickness is small. If too much, the durability of the head 3 tends to be lowered. From such a viewpoint, the thicknesses t3 and t5 are preferably 0.7 mm or more, more preferably 0.8 mm or more, and the upper limit is preferably 1.1 mm or less, more preferably 1.0 mm or less. Is desirable.

  Further, the sole portion 3c has an opportunity to come into contact with the ground during a swing. For this reason, in order to ensure durability, it is desirable to form with thickness t4 larger than crown part 3b preferably. On the other hand, if the thickness t4 is too large, the head weight tends to increase, which is not preferable. From such a viewpoint, the thickness t4 of the sole portion 3c is preferably 0.9 mm or more, more preferably 1.1 mm or more, and the upper limit is preferably 1.5 mm or less, more preferably 1.3 mm or less. Is desirable.

  The weight of the head 3 is not particularly limited, but if it is too small, the kinetic energy of the head 3 at the time of swing is relatively lowered, and there is a tendency that the effect of increasing the flight distance due to the lengthening of the club cannot be exhibited sufficiently. is there. On the other hand, if the weight of the head 3 is too large, it tends to be difficult to realize a club specification that is easy to swing as described later. From such a viewpoint, the weight of the head 3 is preferably 180 g or more, more preferably 185 g or more, and the upper limit is 195 g or less, more preferably 193 g or less, and further preferably 191 g or less.

The volume of the head 3 is not particularly limited, but if it is too small, it tends to be difficult to increase the moment of inertia of the head, and conversely, if it is too large, the air resistance tends to increase and it is difficult to swing. From this point of view, the volume of the head 3, preferably 350 cm ³ or more, more preferably 400 cm ³ or more, more preferably 420 cm ³ or more is desirable, the upper limit is preferably 470 cm ³ or less, more preferably 460 cm ³ or less Is desirable.

  The head 3 as described above can be manufactured by various methods. For example, it can be manufactured by preparing a plurality (for example, 2 to 4) of head components and joining them appropriately. The head component can be formed by, for example, casting, forging, press forming, or a combination thereof. Further, as a method for joining the head components, for example, welding, adhesion, brazing, diffusion joining, caulking, or the like can be used. As shown in FIG. 7, the head 3 of the present embodiment is made up of a head main body portion 3 </ b> A made of an integrally cast product having an opened sole portion, and a sole plate portion 3 </ b> B fitted into the opening and welded. Yes.

  The shaft 2 is made of, for example, fiber reinforced resin. The shaft 2 made of a fiber reinforced resin is formed by, for example, laminating and vulcanizing a sheet-like prepreg (in which an uncured or semi-cured thermosetting resin is impregnated with parallel reinforcing fibers). Can be formed. Since such a shaft 2 is lightweight, it is easy to swing out and has a high degree of design freedom that can easily set the weight balance of the shaft, which is useful for free adjustment of swing balance.

  As a specific manufacturing method of the shaft 2 described above, a step of winding a plurality of prepregs around a mandrel to form a cylindrical prepreg laminate, a step of removing the prepreg laminate from the mandrel, and the inside of the prepreg laminate Examples thereof include an internal pressure molding method including a step of inserting an expandable bladder and the like and a step of applying heat and pressure to the bladder to press the prepreg laminate against the inner surface of the mold and heat molding. Thereby, the shaft 2 is configured as a tapered pipe body whose outer diameter is smoothly reduced from the rear end 2B to the front end 2A. In addition to this, for example, a tape winding method or a filament winding method can be adopted as a method for manufacturing the shaft 2.

  The reinforcing fiber of the prepreg is not particularly limited. For example, in addition to carbon fiber and glass fiber, metal fiber such as amorphous, poron, titanium, tungsten or stainless steel, or organic such as aramid or polyparaphenylenebenzobisoxazole (PBO). A fiber etc. can also be used, Preferably a carbon fiber is desirable. An epoxy resin is suitable for the matrix resin of the prepreg.

  FIG. 8 shows an example of a configuration diagram in which a prepreg constituting the shaft 2 is developed. In the figure, only numerical values indicate the length and width of the prepreg, and the unit is millimeters. The indication of angle (°) indicates the fiber orientation angle with respect to the axial direction of the shaft. The prepreg constituting the shaft 2 of the present embodiment includes a main prepreg 6 disposed over substantially the entire length of the shaft 2, a small-length front end side auxiliary prepreg 7 disposed only on the front end side 2A, And a rear end side auxiliary prepreg 8 having a small length disposed only on the rear end side 2B. Each prepreg is a unidirectional prepreg in which carbon fibers are aligned in one direction.

  The main prepreg 6 includes at least one straight prepreg 6a in which fibers are arranged parallel to the axial direction of the shaft, and in this embodiment, at least one in which the fibers are inclined with respect to the longitudinal direction of the shaft. In this embodiment, the one including three bias prepregs 6b is exemplified. The bias prepreg 6b in this example includes ones having fiber orientation angles of ± 45 ° and 90 °.

For the straight prepreg 6a, for example, fibers having a tensile elastic modulus of 10,000 to 30,000 kgf / mm ² are preferably used. The bias prepreg 6b includes a fiber having a higher tensile elastic modulus than that of the straight prepreg, in particular, a fiber having 24000 kgf / mm ² or more, more preferably 30000 kgf / mm ² or more and 80000 kgf / mm ² or less, more preferably 60000 kgf / mm ² or less. Is preferred.

In general, the fiber having a higher tensile elastic modulus tends to have a lower tensile strength. For this reason, it is desirable to secure the strength of the shaft 2 by using a fiber having a tensile elastic modulus of 30000 kgf / mm ² or less for the straight prepreg 6a that greatly affects the bending strength of the shaft 2. On the other hand, since the bias prepreg 6b has little influence on the bending strength of the shaft 2, the use of fibers having a large tensile elastic modulus as described above makes the shaft light in weight and small in twist (torque) and excellent in directivity. Can be obtained. In addition, let the tensile elasticity modulus of a fiber be the value measured according to "the carbon fiber test method" of JISR7601.

Moreover, the said front end side auxiliary prepreg 7 consists of four sheets by this embodiment, for example, is formed with the length of the shaft axial direction of 200-350 mm. For the prepreg 7, for example, a fiber having a tensile modulus of about 10,000 to 30,000 kgf / mm ² is preferably used. The orientation angle of the fibers is preferably 0 ° and ± 45 ° with respect to the axial direction of the shaft.

Further, the rear end side auxiliary prepreg 8 is composed of one sheet in the present embodiment. The prepreg 8 is formed from the rear end of the shaft with a length in the shaft axial direction of, for example, 35 to 450 mm. For this prepreg 8, for example, a high elastic fiber having a tensile elastic modulus of about 26000 to 80000 kgf / mm ² is preferably used. The fibers are oriented in the axial direction of the shaft, but are not limited thereto.

  The grip 4 is made, for example, by molding and vulcanizing a material obtained by mixing and kneading oil, carbon black, sulfur and zinc oxide with natural rubber into a predetermined shape. In this embodiment, the grip length is 272 mm (about 10.7 inches) and the grip weight is 40 to 50 g.

  In the club 1 of the present embodiment, as shown in FIG. 9 or FIG. 10, a weight member 9 is arranged on the rear end 2A of the shaft 2 or the rear end 4e side of the grip 4.

  In the embodiment of FIG. 9, the weight member 9 is fixed to the rear end 2 </ b> B of the shaft 2. The weight member 9 of the present embodiment is provided with a base portion 9A that can be inserted into the hollow portion from the rear end 2B of the shaft 2 and a flange portion 9B provided on the base portion 9A. The weight member 9 can be integrally fixed to the shaft 2 so as not to move, for example, by a screw groove and / or an adhesive provided in the base portion 9A. The flange portion 9B serves to prevent the weight member 9 from moving in the shaft 2.

  In the embodiment of FIG. 10, the weight member 9 is fixed to the rear end 4 e side of the grip 4. The weight member 9 in this example has a ring shape, and its center is substantially aligned with the center of the shaft 2. Such a weight member 9 is previously charged in rubber at the time of vulcanization molding of the grip, and can be fixed to the grip 4 so as to be immovable by integral vulcanization.

  The rear end surface of the grip 4 is usually provided with an air vent hole 4H that penetrates the inner surface of the grip. The air vent 4H is provided to exhaust the air between the grip and the shaft 2 to the outside when the grip 4 is attached to the rear end of the shaft 2 and to improve the mounting property. The ring-shaped weight member 9 of the present embodiment does not block the air vent hole provided in the rear end surface of the grip 4, and thus does not impair the grip 4 mountability.

  In any aspect, the weight member 9 is made of a high specific gravity material having a large specific gravity in order to secure a large weight while being small. The high specific gravity material is not particularly limited as long as the specific gravity is higher than that of the shaft 2, but a metal material such as tungsten, a tungsten alloy, a copper alloy, or a nickel alloy can be preferably used, and a specific gravity is particularly preferable. Is preferably 5.0 or more, more preferably 6.0 or more, and even more preferably 7.0 or more. Note that, even if the specific gravity is too large, the workability and productivity of the material are likely to be lowered. Therefore, the specific gravity of the high specific gravity material is preferably 13.0 or less, more preferably 12.0 or less, and even more preferably 11. 0 or less is desirable.

  The weight member 9 is preferably 2% or more of the weight of the head 3, more preferably 3% or more, and still more preferably 4% or more. When the weight member 9 is 2% or less of the weight of the head 3, the effect of reducing the swing balance of the club 1 tends to be insufficient. On the contrary, if the weight member 9 is too heavy, the total weight of the club 1 becomes large, and it becomes difficult to swing despite the small swing balance. From such a viewpoint, the weight of the weight member 9 is preferably 9% or less, more preferably 8% or less of the head weight.

11, a conventional golf club, shows the results of measuring the moment of inertia I _G and the swing balance. As is apparent from FIG. 11, some conventional 45-inch clubs have a swing balance of D0 or smaller, but golf clubs of 46 inches or more have a swing balance exceeding D0. . As for the moment of inertia I _G, can be read increases in almost proportional to the swing balance.

On the other hand, as described above, the club 1 of the present embodiment has a lighter head 3, a lighter shaft 2, an increased relative weight on the rear end side of the shaft 2, and / or a weight member 9. at least one means, such as placement, the swing balance by 14 inches balance measurement method C5～D0, and the moment of inertia I _G of the club at the rear end 4e of the grip 4 is made 2850~3000kg · cm ^2. In other words, while the club entire length from 46 to 48 inches and the long, the moment of inertia I _G and the swing balance at the rear end of the grip, can in clubs and comparable conventional 45 inches.

Such a club 1 can be expected to improve the head speed by increasing the length. Also, the club 1 of the present embodiment, since the swing balance and inertia moment I _G there is no short clubs and emphatic around 45 inches at the beginning of the backswing, at each timing during before and crosscut hits the ball, The operability of the club can be enhanced sufficiently.

From the above viewpoint, the swing balance of the club 1 is particularly preferably C6 to C9. Further, the moment of inertia I _G is especially preferably 2870kg · cm ² or more, more preferably 2900kg · cm ² or more, most preferably 2930kg · cm ² or more is desirable, desirable 2980kg · cm ² or less for the upper limit.

  In addition, as described above, a golf club having a long length often hits with the face open without hitting the golf club head back to the addressed state when hitting a ball. In particular, when the head speed is increased due to the reduced swing balance, such a tendency is more likely to appear. Therefore, in the present invention, the center-of-gravity distance HGL of the head 3 is set to a small value of 35 mm or less. Thereby, since the center of gravity HG of the head 3 is relatively closer to the heel side, the return (or return) of the head 3 during the swing is improved, which is useful for preventing slices and the like.

  In addition, when the center of gravity distance HGL exceeds 35 mm, a so-called “toe down phenomenon” in which the toe side of the head 3 falls during the swing is likely to occur, and as a result, the head 3 is likely to hit the ground. 1 can suppress such duffing. On the other hand, when the center-of-gravity distance HGL is remarkably small, the return of the head 3 is excessively improved, and the directionality of the hit ball is likely to be deteriorated, such as being easily hooked to the hook or the left direction. From such a viewpoint, the center-of-gravity distance HGL is preferably 30 mm or more.

Furthermore, in the present invention, the moment of inertia of the head 3 around the axial center line CL of the shaft ² is set to 5500 to 6000 g · cm ² . This moment of inertia can also optimize the return of the head 3 during the swing. That is, when the moment of inertia of less than 5500 g · cm ^2, the return of the head is excessively increased, the hitting is likely caught in the left direction, when a reverse in excess of 6000 g · cm ^2, the slice is likely to occur. From such a viewpoint, the moment of inertia of the head 3 around the axial center line CL of the shaft 2 is preferably 5600 or more, and 5980 or less.

  As described above, the club 1 of the present invention is easy to swing while increasing the head speed. Therefore, accurate back swing and club control can be expected. Further, toe down is prevented and the return of the head during the swing is optimized. As a result, slicing and hooking are suppressed. Therefore, it is possible to fly the ball accurately and farther in the target direction.

  In the present embodiment, the total weight of the club 1 is not particularly limited, but if it is too large, a feeling of weight is likely to occur even if the swing balance is reduced, and conversely, if it is too small, the timing at the time of swinging is difficult to take. There is a tendency to spoil the sex. From such a viewpoint, the total weight of the club 1 is preferably 285 g or more, more preferably 289 g or more, and the upper limit is preferably 300 g or less, more preferably 298 g or less.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  Based on the specifications in Table 2, a wood-type golf club (driver) was prototyped. The basic structure of the club is as described above. Each specification is adjusted by changing the head volume, head weight, shaft weight and / or weight member weight. Each club was tested for ease of swing, flight distance and directionality of the hit ball. The test method is as follows.

<Ease of swinging>
Thirty golfers with a wide skill level of handicap 5 to 30 actually hit golf balls 10 by 10 and performed sensory evaluation on the ease of swinging. The criteria for scoring were as follows and displayed as the average of 30 people. The larger the value, the better.
5: Easy to swing 4: Easy to swing 3: Normal 2: Slightly difficult to swing 1: Very difficult to swing

<Hit distance of hit ball>
Each test club was attached to a swing robot (Golf Laboratories), and the swing speed of the robot was adjusted so that the head speed in Comparative Example 7 was 40 m / s. Then, 10 golf balls were hit at each club, and the average value of carry was displayed. The larger the value, the better.

<Direction of hit ball>
The game was conducted by hitting 10 golf balls for 10 handicap 10-20 intermediate to advanced golfers. Evaluation was made by measuring the deviation of the stop position of the ball with respect to the target flying ball line (the shortest distance measured in the direction perpendicular to the target flying ball line) and displaying the average value. Note that the deviation is a positive value regardless of whether the deviation is in the right direction or the left direction. The smaller the value, the better the directionality.
Table 2 shows the test results.

  As a result of the test, it was confirmed that the head of the example was easier to swing than the comparative example. As a result, it was confirmed that the head was excellent in the flight distance and directionality of the hit ball even though it was long.

1 is a front view of a golf club showing an embodiment of the present invention. It is a diagram explaining the club full length. It is a diagram explaining a swing balance. It is a diagram explaining the scale of a swing balance measuring device. It is a diagram explaining the measuring method of the moment of inertia in the rear end of a grip. The center of gravity distance of the head will be described, in which (A) is a plan view of the golf club in a reference state, and (B) is a cross-sectional view at the vertical plane VP. It is an expanded sectional view of a golf club head. It is an expanded view of the prepreg which comprises a shaft. It is sectional drawing of the rear end side of the club which shows a weight member. It is sectional drawing of the rear end side of the club which shows another weight member. It is a graph which shows the relationship between the moment of inertia in the rear end of a grip, and swing balance about the conventional club.

Explanation of symbols

1 Golf Club 2 Shaft 3 Golf Club Head 4 Grip 4e Grip Rear End

Claims (6)

A golf club having a shaft, a golf club head fixed to the front end side thereof, and a grip provided on the rear end side of the shaft,
The total club length is 46 to 48 inches.
The swing balance by the 14-inch balance measurement method is C5 to D0,
The moment of inertia of the club at the rear end of the grip is 2850 to 3000 kg · cm ² ,
A golf club characterized in that a golf club head has a center-of-gravity distance of 30 to 35 mm, and a golf club head has a moment of inertia of 5500 to 6000 g · cm ² around an axial center line of the shaft.   The golf club according to claim 1, wherein the total weight of the club is 285 to 300 g. The golf club according to claim 1, wherein a moment of inertia of the club at a rear end of the grip is 2900 to 2980 kg · cm ² .   The golf club according to claim 1, wherein the swing balance is C6 to C9.   The golf club according to claim 1, wherein the weight of the golf club head is 180 to 195 g.   6. A weight member having a weight of 2 to 9% of the weight of the golf club head is disposed on the rear end side of the shaft or the rear end side of the grip. Golf club.

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