JP2992470B2 - Golf club set - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In a golf club set comprising a plurality of clubs formed such that the length of the shaft gradually decreases as the loft of the head gradually increases, the moment of inertia around the shaft axis of the head and the shaft axis of the club It is an invention relating to the torsional frequency around.

[0002]

2. Description of the Related Art With respect to golf clubs, the shape, structure, material, and the like are defined in the Rules of Golf, and performances that are essentially contrary to tradition and customs cannot be used. Club, the length of the shaft follows the head loft increases gradually is divided by the length of the formed shaft for gradually decreasing, smaller numbers from the longer of the shaft is attached as count.

The contents of a general set in a wood club are basically set from No. 1 called a driver to No. 5 called a clique, and are provided as a wood set. On the other hand, the contents of a general set of iron clubs are divided into long irons, middle irons, short irons, and wedges, which are special irons. , 1st, 2nd, 3rd for long irons (hereinafter referred to as 1I, 2I, 3I)
And the middle irons are numbered 4, 5, and 6 (hereinafter 4
I, 5I, and 6I), short irons have 7, 8, and 9 (hereinafter, 7I, 8I, and 9I), wedges have sand wedges and pitching wedges, and these are called iron sets. Called and provided.

[0004] Wood clubs are required to have a good hitting distance and a good hitting direction. In an iron club, a golfer hits a ball at various hitting positions to determine how the player intends. It is required that the club be able to approach and stop the ball, and the ball struck by the player in a predetermined swing will fly with a predetermined ball trace (trajectory) and fly to reach the desired position The set is referred to as a golf club set (hereinafter referred to as a set) and is generally provided.

[0005] However, it is generally said that a club having a lower number in the set is more difficult to swing than a club having a higher number. The reason is that the club is long and the loft angle of the head is small, so that it is more difficult to keep the face condition normal at impact compared to a club with a shorter shaft, and it is difficult to meet accurately. Is a factor. In addition to this, especially for clubs having a small number of clubs, there are golfers who express themselves as "clubs with easy head return" or "clubs with difficult head return", and this is due to the elasticity and rigidity of the shaft. It is known to be related.

Therefore, when a conventional head is examined,
In general heads, the smaller the count, the lighter the weight and the smaller the distance from the shaft axis to the center of gravity,
The moment of inertia about the shaft axis of the head is also reduced. Therefore, before the impact of a general golfer's swing, in a club of a small golf club, the head does not return and the hit ball flies with a ball trace that generally flies rightward (this is called a slice ball). In many cases, head returns between sets were not constant.

[0007] The cause is also in the manufacturing method of the shaft.
The shaft was manufactured to be long according to the club with the smallest number, and this long shaft was cut off the head side and the grip side so as to fit the large club, so when looking at the whole set, Inevitably, a club having a larger number, ie, a club having a shorter shaft, has a higher torsional rigidity, while a club having a smaller number, ie, a club having a longer shaft, has a lower torsional rigidity, and a club having a smaller number has a higher tendency to be twisted. Therefore, when the ball is hit, the head tends to open, and a phenomenon has occurred that the head is difficult to return.

[0008] Therefore, regarding the phenomenon of head return, FIG. 1 shows a swinger type right-handed average golfer with a head speed of 35 to 40 m / s using clubs of 9I, 6I and 3I among the set of conventional clubs. When the amount of opening of the head at the time of impact is measured by an experiment according to the method shown in the above, the club having a smaller number has a smaller torsional rigidity than a club having a larger number.
The smaller the club number, the slower the head returns compared to the larger club number, the head is generally open to the right with respect to the swing trajectory at impact, and the hit ball flies with a ball trace that generally flies to the right I do.

FIG. 3 shows the time change of the torsion angle of the shaft with respect to the grip during the downswing. In the conventional club, the shaft is hardly twisted until the cock is released during the downswing, and after the cock is released. Once turned to the right with respect to the swing trajectory,
It can be seen that the head is heading roughly in the direction of the swing trajectory before impact.

When the torsion angle of the head with respect to the grip of the conventional club immediately before impact is measured by the method shown in FIG. 1, 3I is 2.0 degrees open and 6I is 1.0 degrees.
9I was opened 1.7 degrees.
Therefore, in order to measure the torsional angle and torsional rigidity of only the shaft of this club, a portion 840 mm from the tip of the shaft is fixed by the method shown in FIG.
A torsional moment of 1 ft · lb was applied to a part of mm. At this time, 3I is 3.06 degrees, 6I is 2.88 degrees, 9
I was 2.70 degrees, and it was found that the club having a longer shaft had lower torsional rigidity.

The torsion angle and the like of the club head portion during the downswing can be analyzed using the following equation 1, and can be considered together with the results of the above experiment.

(Equation 1)

The contents of the symbols used in Equation 1 are as follows.

G: lateral elastic modulus of the shaft, I: secondary moment of area of the shaft, 1: club length, ω _n : torsional frequency of the golf club, J: moment of inertia of the head around the shaft axis, κ: The constant if the shaft is twisted,
T: The strength of the torque applied by the golfer to the grip from the waist, shoulders, arms, and wrists during the downswing. Ω: The rotation of the golfer to rotate the grip from the waist, shoulders, arms, and wrists around the axis during the downswing. Speed, t: time during downswing, Tsin ωt: torque applied to the grip by the golfer, θ: twist angle of the club head, GI:
The torsional rigidity of the shaft .

The rotational motion of the club head during the downswing can be analyzed using equation (1). FIG. 2 is a schematic diagram illustrating the rotational movement of the club head during a downswing. The time t = 0 during the downswing. The torsion angle θ of the club head is 0. If dθ (0) / dt = 0, the torsional angle θ (t) of the club head at the time t during the downswing is It looks like an expression. According to the formula, it is understood that the return of the head depends on the magnitude of the torque T applied to the grip portion by the golfer from the waist, shoulders, arms, and wrists during the downswing. The return of the head depends on various characteristics of the club, that is, the torsional frequency ω _n of the golf club, the torsional rigidity GI of the shaft, the moment of inertia J of the head about the shaft axis, the torsional spring constant κ of the shaft, and the like. I understand that. Next, the relationship between various characteristics of the club will be described. Assuming that the torsional rigidity of the shaft is GI, the relationship between the torsional rigidity GI and the torsional spring constant κ of the shaft is given by an equation. Here, the torsional rigidity GI of the shaft is given by the product of the lateral elastic modulus G of the shaft and the secondary moment of area I of the shaft. It can be seen from the equation that the torsional rigidity GI of the shaft reflects the torsional constant κ of the shaft. On the other hand, the twist constant κ of the shaft and the torsional frequency ω _{n of the} golf club
Is related to the moment of inertia J around the shaft axis of the head.
And is given by the equation: The method of measuring the torque of the shaft itself (the expression of this torque is not the physical term torque but refers to the torsional rigidity of the shaft in the golf goods industry belonging to the present invention) is shown in FIG. It can be measured by the method.

[0015] These, head it can be seen that all the count is returned in the same way if the properties of the shaft axis of the moment of inertia J of the head, the vibration frequency omega _n twist golf club club same between count. Furthermore, in order to improve the head return for a club having a smaller number, it is necessary to use a golf club.
The torsional vibration number ω _n of love, it can be seen that there is a need to be larger as the count is small club. Also, for this purpose, the spring rate κ if torsion of the shaft, fixed between count, or, must be large enough count is smaller clubs, shea
It can be seen that the torsional rigidity GI of the shaft needs to be increased as the club number becomes smaller.

A prior application relating to the change rate of the torsional frequency of the shaft between the counts is disclosed in Japanese Patent Application Laid-Open No. 60-25647.
The invention of No. 1 "golf club set" is provided.
In the claims of the present invention, "the rate of change of the torsional frequency of the shaft between the clubs with respect to the change of the number of counts is substantially constant", or "the rate of change of the torsional frequency of the shaft is 0", or , "A golf club set characterized in that the rate of change of the torsional frequency of the shaft is a value larger than 0" or "the rate of change of the torsional frequency of the shaft is set to a value smaller than 0", As an effect, it is described that "the face surface is formed so that the orientation of the face surface at the time of impact with respect to the downswing characteristic between the counts can be made constant".

Further, the description of "torsional vibration of the shaft during the downswing leading to ball impact" indicates that the shaft exhibits a sinusoidal torsion during the downswing in the description "indicating periodicity". However, as a result of an experiment conducted by the method shown in FIG. 1 described above, a sine wave is not obtained as shown in FIG. Furthermore, the torsional behavior of the shaft is dominated by the forcible torque applied to the grip by the golfer, and the torsional vibration of the club is attenuated by the golfer's hand. It can not be said that it is formed so that the orientation of the face surface at the time of impact on the swing characteristics can be made constant.

Japanese Patent Application Laid-Open No. 56-16106 discloses a prior application regarding torsional rigidity and torsional frequency of a club shaft.
The invention of No. 8 "Golf club shaft" is provided. Claim 3 of the invention states that "the torsional stiffness of each club or shaft is substantially constant or increases substantially uniformly as the length increases throughout the set. a is described as a golf club or shaft that of the one-set "which is characterized, furthermore,
Claim 7 states that "one set of golf clubs or shafts thereof, in which the frequency of the torsional vibration of each club or shaft is substantially constant throughout the entire set," In order to manufacture a shaft, there is described that "the outer diameter of the shaft and the thickness of the wall thickness are changed along the longitudinal direction of the shaft, and the material of the shaft is selected", and an embodiment thereof is disclosed.

[0019]

When attention is paid to the return of the head immediately before impact during a downswing, even if the rate of change of the "torsion frequency of the shaft" between the counts is constant, the type of the head and the shaft Due to the peripheral moment of inertia, it cannot always be said that it is possible to "form so that the orientation of the face surface at the time of impact on the downswing characteristics between the counts can be made constant".

[0020] Also, a one-set golf club characterized in that the torsional stiffness of each club or shaft is substantially constant or increases substantially uniformly as the length increases throughout the set. Clubs or shafts thereof '' or `` one set of golf clubs or shafts in which the frequency of the torsional vibration of each club or shaft is substantially constant throughout the set ''
By "changing the outer diameter of the shaft and the thickness of the wall thickness along the longitudinal direction of the shaft", it is certain that "the torsional stiffness of the shaft is substantially constant or substantially increased as the length increases throughout the set. Or "the frequency of the torsional vibration of each club or shaft is
Although it becomes "substantially constant throughout the entire set", the bending stiffness (flexural rigidity) and weight of the shaft change, causing a problem that the feeling changes when swinging with a club equipped with this shaft, In the phenomenon of return, there is a part that does not elucidate the relationship with the torsional rigidity and torsional frequency, and a part that does not mention the relationship with the moment of inertia about the shaft axis of the head, and this shaft has a `` stepped This is a method that is not compatible with fiber-reinforced plastic shafts (hereinafter referred to as FRP shafts).

[0021]

SUMMARY OF THE INVENTION According to the present invention, the phenomenon of head return is formed in a harmonious state in the entire set, and a ball hit by a player in a predetermined swing is set to a predetermined trajectory of a flying ball (trajectory). ), The golf club set designed to fly and reach a desired position can be provided, and the opening amount of the head at the time of hitting the ball, that is, the twist angle of the head portion of the club, is determined for each count. Is set intentionally.

Therefore, according to the present invention, in accordance with the opening amount of the head, the club having a smaller inner number in the set has a constant moment of inertia about the shaft axis of the head and the club having a smaller number of clubs than the club having a larger number. An object of the present invention is to solve the above-mentioned problem by keeping the torsional frequency around the shaft axis constant or increasing the torsional frequency without significantly changing the bending characteristics of the shaft.
Also, according to the present invention, in accordance with the opening amount of the head, the club having the smaller internal number in the set has a constant moment of inertia about the shaft axis of the head as compared with the club having the larger internal number, and the club has a smaller axial moment. The object of the present invention is to solve the above-mentioned problem without increasing the bending characteristics of the shaft by increasing the torsional rigidity of the shaft in order to make the torsional frequency constant or increase the torsional frequency of the shaft.

The torsional frequency of the club is constant or
As a means to increase, also, the present invention as a means to increase the stiffness twist shaft, the free range varying much bending characteristics and weight of the shaft, slightly increasing the outer diameter and wall thickness of the shaft smaller clubs of count This is a club set to which a shaft is manufactured by using a method of causing the head to have a constant moment of inertia about the shaft axis of the head between the counts. Further, the present invention is applicable to a means for increasing or decreasing the torsional frequency of a club and for increasing the torsional rigidity of a shaft.
When referring to the P-shaft, a fiber having a smaller orientation number as a club has an orientation angle.
A fiber having a high elastic modulus is used to increase the torsional rigidity. -The smaller the club number, the greater the number of turns of the fiber layer having the orientation angle to increase the torsional rigidity. The torsional rigidity is increased by making the winding angle of the fiber layer having an orientation angle closer to ± 45 degrees with respect to the axis in the longitudinal direction of the shaft as the club number becomes smaller. (The relationship between the transverse elastic modulus G of the FRP shaft and the winding angle of the FRP fiber layer having the orientation angle is approximately sinusoidal as the winding angle increases from 0 degrees as shown in FIG. It is known that the shaft is manufactured using such means as a peak at a degree, and the club set is equipped with a head in which the moment of inertia around the shaft axis of the head is kept constant between counts. is there.

Examples of the method of manufacturing the FRP shaft include a sheet winding method in which a prepreg obtained by impregnating a thermoset resin in a aligned carbon fiber or glass fiber is wound around a mandrel as a core metal, and the mandrel is removed after heat curing. Similarly, it is manufactured by impregnating thermosetting resin into aligned carbon fiber and glass fiber filament fibers, winding directly on the mandrel as the core metal, heating and curing, and then removing the mandrel using the filament winding method or any other means. It is possible to

[0025]

According to the present invention, functionally, the torsional vibration frequency of the club is set to be constant or larger as compared with a club with a larger club number, in accordance with the opening amount of the head. In addition, since it is a club set equipped with the moment of inertia around the shaft axis of the head fixed between the counts, the head return phenomenon is harmonized with the entire set, or the club returns with the smaller number of clubs The ball hit by a predetermined swing by the player flies with a predetermined ball trace (trajectory) of the flying ball, and has an effect of reaching a desired position.

[0026]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram relating to a method of measuring the return of a head at the time of impact. FIG. 2 is a schematic diagram illustrating a rotational motion of a club head during a downswing. FIG. 3 is an explanatory diagram of a time transition of a twist angle of a head with respect to a grip portion during a downswing in a conventional club. FIG. 4 is an explanatory diagram of a time transition of a twist angle of a head with respect to a grip portion during a downswing in a club according to the present invention. FIG. 5 is an explanatory diagram related to a method for measuring a torsional frequency around a shaft axis of a club. FIG. 6 is an explanatory diagram relating to a method of measuring “torque” of a shaft. FIG. 7 is an explanatory diagram related to a method for measuring a torsional rigidity distribution of a shaft. FIG. 8 is an explanatory diagram relating to experimental values of a conventional club torsional frequency and “torque” of a shaft. FIG. 9 is an explanatory diagram relating to experimental values of the torsional frequency of the club and the “torque” of the shaft according to the present invention. FIG.
FIG. 4 is an explanatory diagram relating to measured values of a torsional rigidity distribution of a shaft according to the present invention. FIG. 11 is an explanatory diagram showing a relationship between a transverse elastic coefficient of an FRP shaft and a winding angle of an FRP fiber layer having an orientation angle.

Examples of the method of manufacturing the FRP shaft include a sheet winding method in which a prepreg obtained by impregnating a thermoset resin in a aligned carbon fiber or glass fiber is wound around a mandrel as a core metal, and after heating and curing, the mandrel is removed. Similarly, it is manufactured by impregnating thermosetting resin into aligned carbon fiber and glass fiber filament fibers, winding directly on the mandrel as the core metal, heating and curing, and then removing the mandrel using the filament winding method or any other means. It is possible to

In the following, embodiments of the present invention will be described with a main example of a method of manufacturing using a prepreg in which a thermosetting resin is impregnated into a aligned carbon fiber or glass fiber, which is most commonly employed.

[0029] First, a club wearing the formed FRP shaft as rigid torsion of FRP shaft smaller the count increases, the shaft axis of inertia Meaux head
Placement is constant, and sets the count is small enough club shaft axis of torsional vibration frequency is greater claim 1, or twisting of the club shaft axis between count
6. The set according to claim 5, wherein the torsional frequency is constant.
explain.・ Regardless of the number of shafts, the FRP should be within the range that does not change the bending characteristics and weight of the shaft so much.
The shaft manufactured using the method of changing the elastic modulus and orientation angle of the reinforcing fiber of the shaft and the moment of inertia around the shaft axis of the head are set to 6000 g · cm ² between the counts,
A set with a fixed one, the torsional vibration frequency of the club was 27.0 between the counts by the measurement method shown in FIG.
Hz, and the torsional frequency of each club was set to 27.0 Hz for 9I, 27.5 Hz for 6I, and 3I.
Was measured at 28.0 Hz.

Next, as a fiber layer having an orientation angle as the club count is smaller as claimed in claim 2 or claim 6, using a fiber having a high elastic modulus as a reinforcing material F
The RP shaft set will be described. Higher-count is smaller clubs, as reinforcing fibers of carbon fibers having a high modulus of elasticity as shown in FIG. 9, the 9I, as reinforcing fibers of carbon fibers having an elastic modulus ^{33.0 × 10 3 kgf / mm 2} , Prepreg material 2 with orientation angle + 45 °
An FRP shaft was formed by winding two sheets and two prepreg materials having an orientation angle of -45 °. At this time, the “torque” of the shaft was 2.70 ° / ft · lb. For 6I, two prepreg materials having an orientation angle of + 45 ° and two prepreg materials having an orientation angle of -45 ° were used as reinforcing fibers made of carbon fibers having an elastic modulus of 40.0 × 10 ³ kgf / mm ^2. A wound FRP shaft was formed. At this time, the “torque” of the shaft was 2.65 ° / ft · lb.
In 3I, two prepreg materials having an orientation angle of + 45 ° and two prepreg materials having an orientation angle of −45 ° were formed using carbon fibers having an elastic modulus of 46.0 × 10 ³ kgf / mm ² as reinforcing fibers. A wound FRP shaft was formed. At this time, the “torque” of the shaft was set to 2.65 ° / ft · lb. Further, as shown in FIG. 10 by the measurement method shown in FIG.
Was set so that 3I was larger than 6I.

A description will now be given a set equipped with a FRP shaft using many fibers the number of turns of the fiber layer having an orientation angle as club count of claim 3 or 7, wherein a small as reinforcement. 9I has an elastic modulus of 33.0 ×
Using carbon fibers having a density of 10 ³ kgf / mm ² as reinforcing fibers, two prepreg materials having an orientation angle of + 45 ° and two prepreg materials having an orientation angle of −45 ° were wound. 6I
Has ^three prepreg materials with carbon fibers having an elastic modulus of 33.0 × 10 ³ kgf / mm ² as reinforcement fibers and an orientation angle of + 45 °, and three synthetic resin prepreg materials with an orientation angle of −45 °. Was wound. 3I has an elastic modulus of 33.0 ×
Four prepreg materials having an orientation angle of + 45 ° and four prepreg materials having an orientation angle of −45 ° were wound around carbon fibers having 10 ³ kgf / mm ² as reinforcing fibers.

Next, the winding angle of the fiber layer having an orientation angle as club count of claim 4 or 8, wherein the smaller ± 45
A description will be given of a set equipped with an FRP shaft using a fiber whose torsional stiffness is increased to a degree as a reinforcing material. 9I has an elastic modulus of 46.0 × 10 ³ kg
two prepreg materials having an orientation angle of + 35 ° using carbon fibers having f / mm ² as reinforcing fibers, and an orientation angle of −35
° and two prepreg materials were wound. 6I, a prepreg material 2 having carbon fiber having an elastic modulus of 46.0 × 10 ³ kgf / mm ² as a reinforcing fiber and having an orientation angle of + 40 °.
And two prepreg materials having an orientation angle of −40 ° were wound. 3I has an elastic modulus of 46.0 × 10 ³ kgf / m.
Carbon fiber having m ² as reinforcement fiber, orientation angle + 45 °
, And two prepreg materials having an orientation angle of -45 ° were wound.

Although carbon fibers were used as the reinforcing fibers of the prepreg material used above, glass fibers or metal fibers may be used alone or in combination, for example. Regarding the matrix resin used for prepreg,
A thermosetting resin made of an epoxy resin, a polyester resin, or the like is generally used, but a polyamide resin (nylon) having a thermoplastic property, a polycarbonate resin, or a synthetic resin having the same effect as these can be arbitrarily used.

[0034]

As described above, the torsional rigidity of the head is increased as the count becomes smaller in the set, that is, as the iron shifts to short iron, middle iron, and long iron.
I, 6I, 3I clubs, head speed 35
When measured by a method shown in FIG. 1 by a swinger type average golfer of 40 m / s, FIG.
As the time course of the twist angle of the shaft with respect to the grip portion during the downswing in the club according to the present invention indicates , the twist angle of the head portion with respect to the grip of the golf club set of the present invention immediately before impact is 9I. 1.
6I is 0.5 degree open, 7 degree open,
3I is in a state of substantially zero (square), and it is found that the opening degree of the head is corrected as the length of the iron is longer,
This has the effect of reducing the generation of long iron slice balls that are likely to occur in average golfers. When the torsional stiffness of the club used alone in this experiment was measured by the method shown in FIG. 6, the torsional angle of the shaft per unit torsional moment was 9I of 2.70 degrees, and
6I showed a value of 2.65 degrees and 3I showed a value of 2.60 degrees. When the torsional rigidity distribution of the shaft alone was measured by the method shown in FIG. 7, 6I was larger than 9I, and 3I was larger than 6I. Further, for a club equipped with a head having a moment of inertia around the shaft axis of the head of 6000 g · cm ² , the torsional frequency of the club around the shaft axis was measured by the method shown in FIG.
Hz. In the clubs set in this way, the return of the head of each club is formed in a harmonious state in the entire set, so that the ball hit by the player in a predetermined swing draws a predetermined ball trace (ballistic) of the flying ball. It is possible to fly and reach a desired position.

In addition, in production, a club having a smaller number has an orientation angle as a fiber,
In the manufacturing process, the mandrel, etc., which is the core metal, is equipped with a FRP shaft with high torsional rigidity using fibers with high modulus of elasticity. It has manufacturing advantages that do not require equipment.・ The smaller the club number, the more the number of turns of the fiber layer having the orientation angle is increased and the FRP shaft with the increased torsional rigidity is installed, in accordance with the number of turns of the fiber layer having the orientation angle, with respect to the shaft axis. By reducing the number of windings of the fiber layer having an orientation angle of 0 degree, the mandrel, etc., which is the core metal, is conventionally provided only by contrivance such as using a fiber having a high elastic modulus in the fiber layer. This has a manufacturing advantage that does not require special equipment since only those which are used can be used. The smaller the club number, the higher the torsional stiffness of the FRP shaft with the winding angle of the fiber layer having the orientation angle approaching ± 45 degrees with respect to the longitudinal axis of the shaft. Since the torsional stiffness of ± 45 degrees is the highest, the torsional rigidity of the shaft can be changed only by adjusting the winding angle as the number of clubs increases, using this as the club with the smallest number. It has manufacturing advantages that do not require special equipment.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram relating to a method of measuring head return at the time of impact.

FIG. 2 is a schematic diagram illustrating a rotational movement of a club head during a downswing.

FIG. 3 is an explanatory diagram of a time transition of a twist angle of a shaft with respect to a grip portion during a downswing in a conventional club.

FIG. 4 is an explanatory diagram of a time transition of a twist angle of a shaft with respect to a grip portion during a downswing in the club according to the present invention.

FIG. 5 is an explanatory diagram relating to a method of measuring a torsional frequency of a club around a shaft axis.

FIG. 6 is an explanatory diagram relating to a method of measuring “torque” of a shaft.

FIG. 7 is an explanatory diagram relating to a method for measuring a torsional rigidity distribution of a shaft.

FIG. 8 is an explanatory diagram relating to experimental values of the torsional frequency of a conventional club and the “torque” of a shaft.

FIG. 9 is an explanatory diagram relating to experimental values of the torsional frequency of the club and the “torque” of the shaft according to the present invention.

FIG. 10 is an explanatory diagram relating to measured values of a torsional rigidity distribution of a shaft according to the present invention.

FIG. 11 is an explanatory diagram showing a relationship between a transverse elastic coefficient of an FRP shaft and a winding angle of an FRP fiber layer having an orientation angle.

[Explanation of symbols]

G: Transverse elastic modulus of the shaft I: Secondary polar moment of the section of the shaft 1: Length of the golf club ω _n : Torsion frequency of the golf club J: Moment of inertia around the axis of the head shaft κ: Torsion constant of the shaft T: The strength of the torque applied by the golfer to the grip from the waist, shoulders, arms, and wrists during the downswing ω: The rotation speed at which the golfer rotates the grip from the waist, shoulders, arms, and wrists around the axis during the downswing t: Time during downswing Tsinωt: Torque applied to the grip by golfer θ: Torsion angle of club head GI: Torsion rigidity of shaft T ′: Torsion moment applied to shaft

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-1359 (JP, A) JP-A-1-1666781 (JP, A) JP-A-60-256471 (JP, A) JP-A-63-1988 49175 (JP, A) JP 56-9349 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) A63B 53/00 A63B 53/10

Claims (8)

(57) [Claims] 1. A golf club set comprising a plurality of clubs formed so that the length of a shaft gradually decreases as the loft of a head gradually increases, wherein the inertia of all clubs constituting the set around the shaft axis of the head. moment is constant, and, at the club wearing the formed fiber-reinforced plastic shaft as rigid torsion of the shaft is increased in accordance with the head loft is gradually reduced, a large number of vibration twisting yarn count as club of the shaft axis smaller A golf club set, characterized in that: 2. A fiber reinforced plastic formed so that the torsional rigidity of the shaft increases as the loft of the head gradually decreases.
Stick shaft, as a fiber layer having an orientation angle as count is smaller clubs, golf club set according to claim 1, characterized by using the fiber as a reinforcing material having a high modulus of elasticity. 3. A fiber reinforced plastic formed so that the torsional rigidity of the shaft increases as the loft of the head gradually decreases.
Stick shaft, golf club set according to claim 1, characterized by using a fiber to increase the number of turns of the fiber layer having an orientation angle as count is smaller clubs as reinforcement. 4. A fiber-reinforced plastics formed as rigid torsion of the shaft is increased in accordance with the loft of the head gradually decreases
For the stick shaft , a fiber having a higher torsional rigidity is used as a reinforcing material so that the winding angle of the fiber layer having an orientation angle becomes smaller ± 45 degrees with respect to the longitudinal axis of the shaft as the club number becomes smaller. Claims characterized by the following:
2. The golf club set according to 1 . 5. A golf club set comprising a plurality of clubs formed so that the length of the shaft gradually decreases as the loft of the head gradually increases, wherein the inertia of all the clubs constituting the set around the shaft axis of the head. The moment that is constant, and the torsional frequency of the club around the shaft axis of the club that constitutes the set with the club equipped with the fiber reinforced plastic shaft formed so that the torsional rigidity of the shaft increases as the loft of the head gradually decreases is constant. A golf club set, comprising: 6. The fiber-reinforced plastics formed as rigid torsion of the shaft is increased in accordance with the loft of the head gradually decreases
6. The golf club set according to claim 5 , wherein the stick shaft uses a fiber having a higher elastic modulus as a reinforcing material as a fiber layer having an orientation angle as the club number is smaller. 7. A fiber reinforced plastic formed so that the torsional rigidity of the shaft increases as the loft of the head gradually decreases.
6. The golf club set according to claim 5 , wherein the stick having a smaller number uses a fiber having a larger number of turns of a fiber layer having an orientation angle as the reinforcing material. 8. Fiber-reinforced plastics formed as rigid torsion of the shaft is increased in accordance with the loft of the head gradually decreases
For the stick shaft , a fiber having a higher torsional rigidity is used as a reinforcing material so that the winding angle of the fiber layer having an orientation angle becomes smaller ± 45 degrees with respect to the longitudinal axis of the shaft as the club number becomes smaller. Claims characterized by the following:
5. The golf club set according to 5 .