JPS60256471A - Tennis racket - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a golf club set.

[Conventional technology and problems]

A golf club cent is made up of a plurality of clubs of various counts. Wood clubs are generally available from No. 1 for long distances to No. 7 for short distances, and iron clubs range from No. 1 for long distances to No. 7 for short distances. up to the 9th one in terms of club length, and pinching wedges (10 in terms of club length).
(equivalent to club number) and number wedge (equivalent to number one in terms of club length)
(corresponding to number 0) etc. are prepared. A golf club cent can be made by arbitrarily combining clubs of various counts as necessary.

By the way, the golf swing is made up of five consecutive movements: ■Address, ■Takeback, ■Downswing, ■Impact, and ■Follow-through. Among these movements, particularly during the downswing, a large acceleration is applied to the head. As a result, the shaft causes torsional vibration during the downswing, and at the same time, the head also causes torsional vibration around the axis of the shaft. The head makes an impact while generating these torsional vibrations. If the address and takeback are performed normally, and the time required for the downswing is an integral multiple of the half period of torsional vibration, the direction of the face of the head at impact will be perpendicular to the direction of travel of the head, and the ball will The ball will be launched in the direction of travel of the head. However, if the time required for the downswing is not an integral multiple of the half period of the torsional vibration, the face surface will turn to the right or left with respect to the direction of travel of the head, and the pole will be launched to the right or left. Each shaft number in a golf club set has a unique torsional vibration frequency, but in conventional golf club sets, the torsional vibration frequency of the shaft is not considered at all, and each number of shaft has a unique torsional vibration frequency. have a number.

The reason why the torsional vibration frequency of each number of shaft differs is
The following factors may be considered.

■ Because the shaft length of each count is different.

In other words, the longer the shaft length, the lower the frequency of torsion.

■ This is because the moment of inertia of each shaft around its longitudinal axis is different.

■ This is because the moment of inertia of each shaft number is different.

■ Because the head weight of each count is different.

■ This is because the moment of inertia of the heel around the longitudinal axis of each number of shafts is different.

If the torsional vibration frequency of the shaft of each number is different in this way, in order to keep the direction of the face constant at the time of impact, the time required for the downswing must be adjusted to the torsional vibration frequency of the shaft of each number. However, such adjustments are difficult for ordinary golf players and cause the golf swing to become unstable.
(□In order to stabilize the golf swing, it is desirable to make the time required for the downswing of all clubs the same or to make the rate of change in the downswing constant between clubs. It is desirable that the shaft be formed so that the direction of the face surface at the time of impact can be made constant in response to the downswing characteristics of each club.

[Means for solving problems]

As a means for solving the above-mentioned problems, the present invention calculates the rate of change in the torsional vibration frequency of the shaft between each club with respect to a change in the number of clubs in a golf club centrifuge consisting of a plurality of clubs of various numbers of clubs. To provide a golf club cent characterized by being substantially constant.

[Effect]

In the above means according to the present invention, if the rate of change in the torsional vibration frequency of the shaft between each club is O, then since the torsional vibration frequency of the shaft of each club is the same, the time required for downswing is the same for all clubs. This makes it suitable for golf players.

On the other hand, if the rate of change in the torsional vibration frequency of the shaft between each club as the number of clubs increases is set to a value greater than O, this is suitable for players whose downswing time becomes longer as the number of clubs increases. becomes.

Furthermore, if the rate of change in the torsional vibration frequency of the shaft between each club with respect to the increase in the number of clubs is set to a value smaller than 0, it is suitable for players whose downswing time becomes shorter as the number of clubs increases. Become.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the relationship between the number of clubs, the magnitude f of the torsional frequency of the shaft, and the club length l in a golf club set according to the first embodiment of the present invention. In this figure, the horizontal axis represents the number of the wood club (W) and iron club (1). Here, seven wood clubs (W) are prepared as golf clubs, from the first club for long distances to the seventh club for short distances, and the iron club (1) is for long distances. From the 1st club for golf, to the 9th club for short distances, the pitching wedge (Pw) (equivalent to the 10th club in terms of club length), and the sand wedge (Sw) (equivalent to the 10th club in terms of club length) A total of 11 books have been prepared. In the figure, a solid line I schematically shows the change characteristic of the torsional frequency f of the shaft, and a broken line ■ schematically shows the change characteristic of the club length l. As can be seen from this figure, in this embodiment, the torsional vibration frequencies of the shafts of all clubs are set to be the same (fl), that is, the rate of change of the shaft torsional vibrations between the clubs is set to 0.

In this example, since the club length decreases as the club number increases, the moment of inertia around the longitudinal axis of each shaft (~) and the cross-sectional area of each shaft are adjusted so that the torsional frequency of each shaft is constant. The second moment, the head weight of each club, the moment of inertia of the head around the shaft axis, etc. may be adjusted.

FIG. 4 shows the first golf club (
This figure shows the state of torsional vibration of the shaft 2 and head 3 in the wood club (1).

Referring to this figure, during downswing, the shaft 2 and head 3 torsionally vibrate in the directions of arrows A and B around the longitudinal axis (shaft axis) X of the shaft 2.

FIG. 5 shows the state of torsional vibration of the shaft from time t1 during downswing to time t2 at impact. Here, the shaft undergoes two cycles of torsional vibration between time t1 and time t2.

FIG. 6 uses arrows to indicate changes in the direction of the club face of the golf club having the characteristics shown in FIG. 5 FIIJ. The arrow along the horizontal axis corresponds to the swing direction of the club. As is clear from this figure, the time required for the downswing is the torsional vibration of the shaft.
Since the face surface of the 1-swing ball faces in the same direction as at the start of the downswing, the direction of the ball's flight can always be kept constant.

The golf club set according to this embodiment is suitable for a player who performs a golf swing such that the time required for mid-down swing is the same for all clubs of all numbers.

That is, here, since the torsional vibration frequency of the shaft of each club is the same, a club with a torsional vibration frequency that matches the player's swing is selected so that the required downswing time is an integral multiple of the half period of the torsional vibration. If selected, the direction of the face surface at the time of ball impact will be constant for all clubs, and the direction of ball flight will be constant.

Since the time required for a downswing differs depending on the player, it is desirable to have golf club cents with several types of torsional frequencies available.

FIG. 2 shows a second embodiment of the invention.

In this embodiment, the types of counts of the wood club (W) and iron club (I) of the golf club cents are the same as in the first embodiment. Further, in the figure, a solid line I represents a change characteristic of the torsional frequency f, and a broken line ■ represents a change characteristic of the club length β.

Here, the torsional vibration frequency f of the shaft of each club number is
1~fiO increases at a constant rate of change as the number of counts increases, and pitching wedge PW and sand wedge S
The torsional vibration frequency f10°fil of w is the same. Furthermore, the torsional vibration frequencies of the wood club (W) and the iron club (I), which have the same number of clubs, are the same value.

The golf club set according to the second embodiment is suitable for a player who performs a golf swing such that the time required for a downswing increases as the club number increases. In other words, here, since the torsional vibration frequency of the shaft increases as the number of clubs increases, even if the required downswing time increases with the increase in the number of clubs, the downswing time for each club increases. The time can be adjusted to an integral multiple of the period of torsional vibration of each shaft. therefore,
The same effects as in the first embodiment can be obtained.

FIG. 3 shows a third embodiment of the present invention.

In this embodiment, the types of counts of the wood club (W) and iron club (I) of the golf club cents are the same as in the first embodiment. Further, in the figure, the solid line ■ represents the change characteristic of the torsional frequency f, and the broken line ■ represents the change characteristic of the club length l.

Here, the torsional vibration frequency f of the shaft of each club number is
1 to f10 decrease at a constant rate of change as the number of numbers increases, and pitching wedge PW and sand wedge S
The torsional vibration frequency f10°fll of w is the same. Furthermore, the torsional vibration frequencies of the wood club (W) and the iron club (1), which have the same number of clubs, are the same.

The golf club cent according to the third embodiment is suitable for a player who performs a golf swing such that the time required for a downswing decreases as the club number increases. In other words, here, the torsional vibration frequency of the shaft decreases as the number of clubs increases, so even if the time required for downswing decreases as the number of clubs increases, the downswing of each club The required time can be adjusted to an integral multiple of the period of torsional vibration of each shaft. Therefore, the same effects as in the first embodiment can be obtained.

Note that the types of clubs and types of clubs in the golf club cent according to the present invention are not limited to the embodiments described above. Further, the relationship between the torsional vibration frequency and the club number is not limited to the aspect of the above illustrated embodiment. For example, when the rate of change of the torsional vibration frequency of the shaft is greater than 0 or less than 0, The torsion frequency may be set so that the characteristic line of change in the shaft torsion frequency of the wood club and the characteristic line of the shaft torsion frequency of the iron club are aligned in a straight line.

FIG. 7 shows an apparatus for measuring the torsional vibration frequency of a shaft in a golf club. Referring to this figure, a grip fixing part 11 for fixing the grip 4 of the golf club 1 is provided on the upper part of the main body 10 of the measuring device. Golf club 1 - A head 3 of a 1° club 1 is suspended directly below a grip 4. The main body 10 is provided with a guide rod 12 extending parallel to the shaft 2.

A detection section 13 having a light emitting section 14 and a light receiving section 15 at both ends is slidably attached to the guide rod 12, and the detection section 13 is placed at an arbitrary position by a stopper (not shown) to stop the guide rod. It can be fixed to A lever 16 is attached to the shaft 2 to block the light emitting section 14 and the light receiving section 15.

Now, in the illustrated state, when a torsional load is applied to the head 3 by hand to cause torsional vibration in the shaft 2, the lever 16 moves between the light emitting part 14 and the light receiving part 15 at a specific period. The detection unit 13 detects the period, performs arithmetic processing, and uses the period to block the optical path of the shaft 2.
Calculate the natural torsional frequency of. Then, the calculated value of the torsional vibration frequency is displayed on the display section 17 provided on the main body 10.

The height position of the detector 13 may be adjusted according to the club length of the golf club held by the fixed part 11.

Using this measuring device, it is possible to accurately and easily confirm the torsional vibration frequency of the shaft in the golf club center.

〔Effect of the invention〕

As is clear from the above description, the present invention is capable of keeping the rate of change in the torsional vibration frequency of the shaft between each club almost constant with respect to a change in the number of clubs in a golf club centrifuge consisting of a plurality of clubs of various numbers of clubs. This feature eliminates the need to irregularly change the time required for downswing for each club size, and it becomes possible to perform a stable golf swing. In particular, if you select a club set with a predetermined rate of change in torsional frequency that corresponds to the rate of change in the time required for downswing with respect to the change in number of clubs, the direction of the face surface at impact will be constant for all clubs. In addition, if you select a club center with a predetermined torsional vibration frequency so that the downswing time is an integral multiple of the half period of the shaft's torsional vibration, the face surface at impact will be reduced for all clubs. Since the ball can be oriented in the direction in which the head travels, it is possible to provide a golf club with a stable ball launch direction that matches the golf player's swing characteristics.

[Brief explanation of the drawing]

FIG. 1 is a graph schematically showing the relationship between the club number, the torsional vibration frequency of the shaft, and the club length in a golf club center according to the first embodiment of the present invention, and FIG. A graph schematically showing the relationship between the number of clubs, the torsional frequency of the shaft, and the club length in the golf club set according to the example; FIG. Figure 4 is a partial plan view showing the state of torsional vibration of the shaft and head in a golf club, and Figure 5 is a graph schematically showing the relationship between the torsional vibration frequency of the shaft and the club length. Figure 6 is a diagram showing the periodicity of the torsional vibration of the shaft during the downswing leading to pole impact. Figure 6 is a diagram showing the change in the direction of the face of the head during the downswing leading to pole impact. Figure 7 is the diagram showing the torsion of the shaft of the golf club. FIG. 1 is a perspective view showing an example of a measuring device for measuring vibration frequency. 1-Golf club 2-Shaft, 3-Head. Patent applicant: Maruman Golf Co., Ltd. Patent agent: Akira Aoki, patent attorney: Nishidate, Japanese patent attorney: Hyakumon, patent attorney: Kuniaki, patent attorney: Akira Yamaguchi, patent attorney: Masaya Hyakude. 1st club number 2nd number 5678 Number 3~ “): Moaning mint” Pw 5w l; Figure 4 Figure 5 Figure 7

Claims (1)

[Scope of Claims] 1. In a golf club set consisting of a plurality of clubs of various club counts, the rate of change in the torsional vibration frequency of the shaft between each club with respect to changes in club counts is made approximately constant. Golf club set. 2. The golf club set according to claim 1, wherein the rate of change in the torsional vibration frequency of the shaft between the respective clubs is set to zero. 3. The golf club set according to claim 1, wherein the rate of change in the torsional vibration frequency of the shaft between the respective clubs with respect to an increase in the number of clubs is set to a value greater than zero. Become. 4. The golf club cent according to claim 1, wherein the rate of change in the torsional vibration frequency of the shaft between the respective clubs with respect to an increase in the number of clubs is set to a value smaller than zero.