JP2013208366A - Golf club shaft fitting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fitting method of a golf club shaft for selecting a shaft matching a golfer based on a swing of the golfer.SOLUTION: A method includes a step of obtaining measurement values from a sensor by hitting a golf ball using a golf club with the sensor attached to a grip of the golf club, the sensor measuring an angular velocity around three axes; a step of determining address, top, and impact of a swing from the measurement values; and a step of selecting a shaft matching a golfer by using at least two swing feature values among the swing feature values obtained from the measurement values.

Description

  The present invention relates to a method for fitting a shaft of a golf club.

  It is an eternal theme for golfers to extend the distance of the ball and to fly it in the direction and angle aimed at. To that end, it is important to use a golf club that fits your swing.

  Selecting a golf club suitable for a golfer is generally referred to as fitting. In order to perform this fitting effectively, it is necessary to consider various factors such as the total weight of the golf club, the weight of the club head, and the length of the golf club. It greatly affects the quality.

For example, one of the physical properties of the shaft is flex. The flex is representative hardness of the shaft a (rigid), forward flex, as shown in FIG. 21, a point 129mm from the tip end 20a of the shaft 20 and the load point W _1, the load point W _When a load Wt of 2.7 kgf is applied to the load point W ₁ with a point of 824 mm from ₁ to the butt end side of the shaft 20 as a fulcrum A and a position of 140 mm from the fulcrum A to the butt end side as an action point B Of the tip end 20a. With respect to this displacement amount F1 (this value is referred to as a forward flex), the flex is determined by a definition such that a certain value f1 to a certain value f2 is an X shaft.

  In general, flex is recommended to have a hardness suitable for the size of the head speed, and a flexible shaft is recommended for golfers with relatively slow head speeds, while it is hard for golfers with relatively fast head speeds. A shaft is recommended. However, this flex does not have a unified standard, and is defined by different standards for each manufacturer. The selection of a suitable flex value often relies on the experience and intuition of the fitting person (fitter), and the selection result is not objective but has individual differences.

In addition, the physical properties of other shafts are in tune. As shown in FIG. 22, the condition is such that a position 12 mm from the tip end 20 a of the shaft 20 is an action point C, and a point 140 mm from the action point C to the butt end side of the shaft 20 is a fulcrum D. as load point _{W 2} points 776mm to butt end side from D, displacement of the butt end 20b when a load Wt of 1.3kgf to the load point _{W 2} F2 a (the value of the reverse flex) Then, T is calculated from the value of this F2 and the above-mentioned F1 (forward flex) according to the following formula (1), and it is determined whether the value of T is a pretone or a hand tone. .
T = F2 / (F1 + F2) × 100 (1)

  The selection of a golf club using this tone also has to rely on the experience and intuition of the person performing the fitting, as in the case of using the flex described above, and the selection results are not objective and have individual differences.

  Therefore, it has been proposed to have a golfer actually perform a swing when fitting, and to perform the fitting from the measurement result of the swing (see, for example, Patent Documents 1 and 2).

  Patent Document 1 discloses a model generation step for generating a golf club model of a golf club used in a golf swing, and a golf club model given a predetermined boundary condition in order to reproduce a golf swing using the golf club model. A characteristic value calculating step for calculating a swing behavior of the club model and calculating a desired dynamic characteristic value of the golf club model in the golf swing, and repeating this characteristic value calculating step while changing the type of the generated golf club model By repeating the step of obtaining the dynamic characteristic value for each of the plurality of golf club models, and extracting the maximum value and the minimum value of the dynamic characteristic value among the plurality of dynamic characteristic values obtained in this repetition step, Based on the difference between the maximum and minimum values, the characteristics of the golf swing are classified. And a swing evaluation step of evaluating, the evaluation method of the golf swing is disclosed.

  Further, Patent Document 2 is a golf club swing evaluation method having a golf club head having a hosel portion on which a golf club shaft is mounted on a crown portion, and the golf club head is installed in a horizontal plane. The golf club swing speed was measured at two points at least 10 mm apart on the intersecting line that includes the axis of the golf club shaft and intersects the plane perpendicular to the horizontal plane and the crown of the golf club head. A swing evaluation method for evaluating a swing based on the speed of each point is disclosed.

JP 2006-230466 A JP 2009-18043 A

However, the method described in Patent Document 1 has a problem that the installation place is limited and the cost is high because a very special and large-scale computing device is required.
Further, in the method described in Patent Document 2, the evaluation of the swing is performed only by the impact, and the characteristics of the entire swing from the address to the impact through the top are not reflected. Therefore, a shaft suitable for a golfer's swing may not be selected, and an improvement has been desired.

  The present invention has been made in view of such circumstances, and since the apparatus to be used can be reduced in size and weight, the selection range of the installation location is wide and more detailed reflecting the entire swing. An object of the present invention is to provide a golf club shaft fitting method capable of fitting on the basis of various shaft specifications.

(1) A golf club shaft fitting method of the present invention (hereinafter also simply referred to as “fitting method”) is a fitting method for selecting a shaft that matches a golfer based on the golfer's swing,
Hitting a golf ball with a golf club having a sensor capable of measuring angular velocities around three axes attached to the grip to obtain a measured value from the sensor;
Determining an address, top and impact in the swing from the measured values;
Selecting a shaft that matches the golfer using at least two of the following swing feature quantities (a) to (c) obtained from the measurement values:
(A) to (c) are selected to correspond to the bending rigidity of the shaft at three positions of 36 inches, 26 inches and 6 inches from the tip end of the shaft, respectively.
Based on the relationship between each of the swing feature values (a) to (c) and the bending rigidity of the shaft, which were created in advance by trial hits, the swing feature values are divided into a plurality of ranges for each position, and each range is supported. And set the range of bending rigidity of the shaft,
From the measured value, a range of the bending stiffness of the shaft at a position corresponding to the at least two swing feature values among three positions of 36 inches, 26 inches, and 6 inches from the tip end of the shaft is obtained.
A shaft that matches the golf club is selected from a plurality of shafts whose bending rigidity at the three positions has been measured in advance, based on a range of the bending rigidity of the shaft at at least two acquired positions. , Golf club shaft fitting method.
(A) Amount of change in grip angular velocity in the cock direction near the top (b) Average value of grip angular velocity in the cock direction from the top until the grip angular velocity in the cock direction reaches the maximum during the downswing (c ) Average grip angular velocity in the cock direction from top to impact

  In the fitting method of the present invention, the shaft can be selected based on at least two of the three swing feature values reflecting not only the limited aspect during the swing of the golfer but also the entire swing from the top to the impact. As a result, fitting can be performed based on more detailed shaft specifications. As a result, it is possible to provide a shaft with better performance (flying distance, directionality, and ease of swinging) for the golfer.

  Further, in the fitting method of the present invention, the swing characteristics can be quantified by simply attaching a sensor to the grip end of the club, and a large-scale equipment such as a conventional camera is unnecessary, so the cost of equipment for fitting is reduced. Is small. Furthermore, the data can be distributed wirelessly to the data analysis device, and the configuration of the entire facility can be simplified, so that it can be easily carried, installed and removed.

(2) In the fitting method of (1), for each of the bending stiffnesses at the three positions, one of a plurality of rank values is given according to the obtained bending stiffness value,
Rank values at three assigned positions from among a plurality of shafts to which any one of a plurality of rank values is assigned according to the measured bending stiffness values at the three positions. The shaft that matches the golfer can be selected based on the above.

(3) In the fitting method of (1), when the swing feature value (a) is 360 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <68.5, and the swing feature When the amount (a) is larger than 360 (deg / s), the bending rigidity EI (N · m ² )> 60.0 is classified,
When the swing feature value (b) is 550 (deg / s) or less, it is classified as bending rigidity EI (N · m ² ) <47.5, and the swing feature value (b) is 550 (deg / s). Is larger, the bending stiffness is classified as EI (N · m ² )> 42.5, and
When the swing feature value (c) is 400 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (a) is more than 400 (deg / s). In the case of large 800 or less, it is classified as 23.0 <bending rigidity EI (N · m ² ) <27.5, and the bending rigidity EI when the swing feature value (c) is larger than 800 (deg / s). It can be classified as (N · m ² )> 25.5.

(4) In the fitting method of (3), when selecting a shaft that matches a golfer using the three swing feature amounts, bending stiffness at three positions corresponding to the three swing feature amounts is measured in advance. Among the plurality of shafts, when there is no shaft that fits the entire range of the bending rigidity of the shaft obtained from each swing feature value, the bending of the shaft obtained from the swing feature value of (c) above. According to the priority order of adaptation of the stiffness range, adaptation of the bending stiffness range of the shaft obtained from the swing feature value of (a), and adaptation of the bending stiffness range of the shaft obtained from the swing feature value of (b). The shaft can be selected.

(5) In the fitting method of (3), when selecting a shaft that matches a golfer using the three swing feature amounts, bending stiffness at three positions corresponding to the three swing feature amounts is measured in advance. Among the plurality of shafts, when there is no shaft that fits all of the range of the bending rigidity of the shaft obtained from each swing feature value, the bending of the shaft obtained from the swing feature value of (a) above. According to the priority order of the fitting of the rigidity range, the fitting of the bending rigidity range of the shaft obtained from the swing feature value of (b), and the fitting of the bending rigidity range of the shaft obtained from the swing feature value of (c). The shaft can be selected.

(6) In the fitting method of (1), for a golfer with a head speed of less than 45.5 m / s,
When the swing feature value (a) is 350 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <60.0, and the swing feature value (a) is from 350 (deg / s). Bend rigidity EI (N · m ² )> 55.5,
When the swing feature value (b) is 550 (deg / s) or less, it is classified as bending rigidity EI (N · m ² ) <45.0, and the swing feature value (b) is 550 (deg / s). Is also larger than 42.5 <bending rigidity EI (N · m ² ) <52.0, and
When the swing feature value (c) is 500 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (c) is more than 500 (deg / s). If the swing feature value (c) is greater than 800 (deg / s) when the swing characteristic amount (c) is greater than 800 (deg / s), the load characteristic is classified as 23.0 <bending rigidity EI (N · m ² ) <26.5. 5 <Bending rigidity EI (N · m ² ) <28.5.

(7) In the fitting method of (1) above, for a golfer with a head speed of 45.5 m / s or more,
When the swing feature value (a) is 360 (deg / s) or less, the swing feature value (a) is classified as 51.0 <bending rigidity EI (N · m ² ) <73.0, and the swing feature value (a) is 360 ( deg / s), it is classified as bending stiffness EI (N · m ² )> 64.0,
When the swing feature value (b) is 550 (deg / s) or less, it is classified as 40.0 <bending rigidity EI (N · m ² ) <50.0, and the swing feature value (b) is 550 ( deg / s), it is classified as 42.5 <bending rigidity EI (N · m ² ), and
When the swing feature value (c) is 300 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (c) is more than 300 (deg / s). If the swing feature value (c) is greater than 550 (deg / s) and less than or equal to 800, it is classified as 23.0 <bending rigidity EI (N · m ² ) <26.5. 24.0 <bending rigidity EI (N · m ² ) <28.5, and when the swing feature (c) is greater than 800 (deg / s), 26.0 <bending rigidity EI ( N · m ² ).

(8) In the fitting method of (6) or (7), when selecting a shaft that matches a golfer using the three swing feature values, bending at three positions corresponding to the three swing feature values in advance is selected. Among the plurality of shafts whose rigidity has been measured, when there is no shaft that fits the entire range of the bending rigidity of the shaft obtained from each swing feature amount, it is obtained from the swing feature amount of (c). Adaptation of the bending stiffness range of the shaft obtained, Adaptation of the range of bending stiffness of the shaft obtained from the swing feature value of (a), and Adaptation of the bending stiffness range of the shaft obtained from the swing feature value of (b) The shaft can be selected according to the priority order.

(9) In the fitting method of (6) or (7), when selecting a shaft that matches a golfer using the three swing feature values, bending at three positions corresponding to the three swing feature values in advance is selected. Among the plurality of shafts whose rigidity has been measured, when there is no shaft that fits all of the bending rigidity range of the shaft obtained from each swing feature amount, it is obtained from the swing feature amount of (a). Adaptation of the bending rigidity range of the shaft obtained, Adaptation of the range of bending rigidity of the shaft obtained from the swing feature value of (b), and Adaptation of the bending rigidity range of the shaft obtained from the swing feature value of (c) The shaft can be selected according to the priority order.

(10) In the fitting method of (1) to (9), when the length of the golf club of the user is different from the length of the golf club having a shaft selected from the plurality of shafts, It is preferable to change the total weight of the golf club based on the difference.

  According to the fitting method of the present invention, the apparatus to be used can be reduced in size and weight, so that the selection range of the installation location is wide and the fitting is performed based on a more detailed shaft specification reflecting the entire swing. Can do.

It is a figure explaining the behavior of the deflection of the shaft during swing. It is a figure explaining three positions of the shaft in which bending rigidity is measured in the fitting method of the present invention. It is a figure explaining the measuring method of the bending rigidity in this invention. It is a figure explaining the method of measuring the swing feature-value in this invention. It is a partially expanded perspective view of a golf club to which a sensor is attached. (A) is a top view of the sensor shown by FIG. 5, (b) is a side view of the sensor. It is a figure which shows the address and takeback in a swing. It is a figure which shows the top and downswing in a swing. It is a figure which shows the downswing and impact in a swing. It is a figure which shows the follow through and finish in a swing. It is a figure which shows the change according to the time passage of the angular velocity of the cock direction in a swing. It is a figure explaining the evaluation criteria of ease of swing. It is a figure which shows the relationship between the swing feature-value (3) and the bending rigidity (EI value) in the measurement point of "6 inches". It is a figure which shows the relationship between the swing feature-value (2) and bending rigidity (EI value) in the measurement point of "26 inches". It is a figure which shows the relationship between the swing feature-value (1) and the bending rigidity (EI value) in the measurement point of "36 inches". It is a flowchart which shows an example of a shaft selection process. It is a flowchart which shows an example of the shaft selection process in the case of low head speed. It is a flowchart which shows an example of the shaft selection process in the case of high head speed. It is explanatory drawing of the flex and tone of five shafts used for verification of the effect of this invention. It is a figure which shows an example of a verification result. It is a figure explaining the measuring method of a forward type flex. It is a figure explaining the measuring method of a reverse type flex.

Hereinafter, embodiments of the fitting method of the present invention will be described in detail with reference to the accompanying drawings.
[Principle of the fitting method of the present invention]
Before describing the embodiment of the fitting method of the present invention, the principle or theoretical background of the fitting method of the present invention will be described. The inventors of the present invention have focused on the fact that the bending of the shaft of the golf club is transmitted from the hand side to the tip side of the shaft as the swing proceeds from the top toward the impact. An assumption is made that there is a correlation between the swing characteristic of a certain golfer from the top to the impact (the details of the swing characteristic will be described later) and the hardness of the shaft matched to the golfer per inch. As a result of extensive research and examination, the present invention has been completed.

  In other words, the golfer's swing when hitting the ball changes from address → top → impact, but the golf club shaft has a relatively heavy head at the tip of the golf club. Bending occurs due to inertia. This bending does not occur in the same part of the shaft in the entire swing process, but is transmitted from the proximal side to the distal end side of the shaft from the top toward the impact as shown in FIG. In other words, as the swing advances from the top toward the impact, the bending position on the shaft moves from the proximal side to the distal end side of the shaft.

  Specifically, when the take-back is performed from the address and the top is reached (the time indicated by (1) in FIG. 1), bending occurs near the hand of the shaft. Next, when turning back and reaching the initial stage of the downswing (at the time indicated by (2) in FIG. 1), the bending moves slightly toward the tip side of the shaft. Further, at the time when the golfer's arm becomes horizontal (the time indicated by (3) in FIG. 1), the bending moves to the tip side from the center of the shaft. And just before the impact (at the time indicated by (4) in FIG. 1), the bending moves to the vicinity of the tip of the shaft.

  In view of the fact that the bending of the shaft at the time of swinging is transmitted from the proximal side to the distal end side of the shaft from the top toward the impact, the inventor has characterized the swing characteristics of the golfer in the time zones (1) to (4). Attempts were made to select the optimal bending stiffness for each inch of the shaft.

Specifically, as shown in FIG. 2, the shaft 20 was divided into three regions, and the bending rigidity at one point in each region was defined. In the present embodiment, a point 36 inches from the tip end 20a of the shaft 20 is a measurement point (1), a point 26 inches is a measurement point (2), and a point 6 inches is a measurement point (3). Then, the bending stiffness at the three measurement points of the shaft 20 is measured and digitized. In this specification, “for every inch” does not mean 1 inch, 2 inches,..., “For a plurality of locations at a distance of a predetermined inch from one end of the shaft, The “predetermined inches” in the present embodiment are 36 inches, 26 inches, and 6 inches from the tip end 20a of the shaft 20 as described above. In this embodiment, three measurements for measuring the bending rigidity of the shaft are 36 inches, 26 inches, and 6 inches from the tip end of the shaft. However, the number of inches is particularly limited in the present invention. It can be changed within a width of ± several inches for each inch. For example, the measurement point (1) can be 36 ± 3 inches from the tip end of the shaft.
Further, in addition to the three measurement points, for example, a point 16 inches from the tip end of the shaft can be used as the measurement point.

The bending rigidity (EI value: N · m ² ) per inch of the shaft can be measured as shown in FIG. 3 using, for example, a 2020 type measuring machine (maximum load 500 kgf) manufactured by Intesco.

  Specifically, the deflection amount α when the load F is applied to the measurement point P from above is measured while supporting the shaft 20 from below at the two support points 11 and 12. In the present embodiment, there are three measurement points P, 36 inches, 26 inches, and 6 inches from the tip end 20a of the shaft 20. The distance (span) between the support point 11 and the support point 12 is 200 mm. Further, the measurement point P is an intermediate point between the support point 11 and the support point 12. The tip of the indenter 13 to which the load F is applied from above is rounded so as not to damage the shaft 20. The cross-sectional shape of the tip of the indenter 13 has a radius of curvature of 10 mm in a cross section parallel to the shaft axial direction. In the cross section perpendicular to the shaft axis direction, the cross-sectional shape of the tip of the indenter 13 is a straight line, and its length is 45 mm.

  The support 14 supports the shaft 20 from below at the support point 11. The tip of the support 14 has a convex roundness. The cross-sectional shape of the tip of the support 14 has a radius of curvature of 15 mm in a cross section parallel to the shaft axial direction. In the cross section perpendicular to the shaft axial direction, the cross-sectional shape of the tip of the support 14 is a straight line, and its length is 50 mm. The shape of the support 15 is the same as that of the support 14. The support 15 supports the shaft 20 from below at the support point 12. The tip of the support 15 has a convex roundness. The cross-sectional shape of the tip of the support 15 has a radius of curvature of 15 mm in a cross section parallel to the shaft axial direction. In the cross section perpendicular to the shaft axial direction, the cross-sectional shape of the tip of the support 15 is a straight line, and its length is 50 mm.

The indenter 13 is moved downward at a speed of 5 mm / min while the support 14 and the support 15 are fixed. Then, when the load F reaches 20 kg, the movement of the indenter 13 is terminated. The deflection amount α (mm) of the shaft 20 at the moment when the movement of the indenter 13 is finished is measured, and the bending stiffness EI (N · m ² ) is calculated according to the following equation (2).
Flexural rigidity EI (N · m ² ) = 32.7 / α (2)

  Then, fitting is performed using the measured bending rigidity of the shaft per inch as an index. The hardness (bending rigidity) of the shaft per inch has a correlation with the swing characteristic with time from the top to the impact, and if the swing characteristic of each golfer is known, the shaft of the shaft per inch suitable for the characteristic is correlated. Hardness can be determined. As described above, the bending or deformation (deflection amount) of the shaft during the swing is transmitted from the top side to the tip side of the shaft from the top to the downswing. In the present invention, focusing on the propagation of this bending, the amount of deflection of the shaft near the top is related to the fast and slow behavior of the grip near the top (angular velocity). Provide a softer shaft for slower golfers.

  In the present embodiment, any one of the rank values in a plurality of stages is given according to the bending rigidity of the shaft measured for each inch by the method described above. Specifically, any one of 10 levels of IFCs is assigned according to the bending rigidity. This IFC is an abbreviation for International Flex Cord, and is an index proposed by the present applicant as representing the hardness of the shaft.

  Tables 1 to 3 below are conversion tables from the EI value of the shaft to the IFC at the measurement points (1) to (3), respectively. The range of shafts that Fitter has prepared to provide to users in consideration of the frequency of use and the method of dividing the shaft hardness into 10 steps for all commercially available shafts. Several methods such as a method of dividing into 10 stages are conceivable. In this embodiment, the latter method is used for fitting. It should be noted that a similar conversion table can be created at other measurement points (for example, 16 inches from the tip end of the shaft described above).

[Swing feature]
In the present invention, as shown in FIG. 4, a golfer who wants to fit a golf club actually makes a swing, and the swing feature value specific to the golfer is measured from the swing. As shown in FIGS. 5 to 6, a sensor 2 capable of measuring angular velocities around three axes is attached to the grip end of the golf club 1 via an adapter 3. The sensor 2 includes a casing 2a made of a box having a square shape in plan view. The casing 2a can be fixed to the grip end by double-sided tape, adhesive, screwing, or the like. In the example shown in FIG. 4, the golfer G is right-handed and is in an address state immediately before starting a swing for hitting the ball B set at a predetermined position.

In order to improve the fitting accuracy, if the length of the user's My Club is different from the length of the golf club based on the shaft stored in the database, the total club weight equivalent to the club length prepared in the database By changing to, a shaft that matches the user can be selected. For example, if the length of a club stored in the database is 45 inches and the user's club length A (mm) is different from 45 inches (= 1143 mm), the total weight of the club swinging for measurement is calculated. The fitting is performed by changing to the one calculated by the following formula (total weight corresponding to 45 inches).
(Total club weight used for measurement) = (A-1143) × 0.377 + (total club weight of my club)

  The sensor 2 is wireless, and the measured data is transmitted wirelessly to a wireless reception device (not shown) built in the computer 10 as a data analysis device. As the wireless communication, for example, Bluetooth (Bluetooth (Bluetooth is a registered trademark)) standard and technology can be used.

  The sensor 2 incorporates an angular velocity sensor (not shown) that can measure angular velocities about three axis directions (x-axis direction, y-axis direction, and z-axis direction). The sensor 2 further includes an A / D converter, a CPU, a wireless interface, a wireless antenna, and a power source. As the power source, for example, a button-type lithium ion battery or the like can be used. The battery may be rechargeable. The sensor 2 may include a charging circuit for charging the battery. An example of the sensor 2 that can be used is WAA-010 (trade name) manufactured by Wireless Technology.

  The wireless receiving device that receives a signal from the sensor 2 includes a wireless antenna, a wireless interface, a CPU, and a network interface.

  A computer 10 serving as a data analysis apparatus includes an input unit 6 including a keyboard 4 and a mouse 5 and a display unit 7. Although not shown, the computer 10 includes a hard disk, a memory, a CPU, and a network interface.

  The sensor 2 detects angular velocities around the x-axis, y-axis, and z-axis. These angular velocities are obtained as analog signals, and the analog signals are converted into digital signals by an A / D converter built in the sensor 2. The output from the A / D converter is transmitted to the CPU, and arithmetic processing such as primary filtering is executed. The data thus processed in the sensor 2 is transmitted from the wireless antenna to the wireless reception device built in the computer 10 via the wireless interface.

  The data transmitted from the sensor 2 is received by the wireless interface via the wireless antenna on the wireless receiving device side. The received data is processed by the CPU of the computer 10.

  Data sent to the computer 10 is recorded in a memory resource such as a hard disk. The hard disk stores programs and data necessary for data processing and the like. This program causes the CPU to execute necessary data processing. The CPU can execute various arithmetic processes, and the calculation results are output by the display unit 7 or a printing device (not shown).

  When the sensor 2 is attached to the grip end, the relationship between the measurement axis and the golf club 1 is considered. In the present embodiment, the z axis of the sensor 2 coincides with the shaft axis of the golf club 1. The x axis of the sensor 2 is oriented along the toe heel direction of the head 1 a of the golf club 1. The y-axis of the sensor 2 is oriented so as to be along the normal direction of the face surface of the head 1a. By attaching the sensor 2 in this way, the calculation can be simplified.

  In this embodiment, a local coordinate system is considered, and the x-axis, y-axis, and z-axis of this local coordinate system are a three-dimensional orthogonal coordinate system. In the present embodiment, the z axis is the shaft axis of the golf club 1, and the x axis is oriented along the toe heel direction of the head 1a. The y-axis is oriented along the normal direction of the face surface of the head 1a.

  That is, the z axis of the local coordinate system matches the z axis of the sensor 2, and the y axis of the local coordinate system matches the y axis of the sensor 2. Further, the x-axis of the local coordinate system matches the x-axis of the sensor 2.

  The sensor 2 can obtain a plurality of continuous data in time series. The number of data per unit time depends on the sampling frequency.

  7 to 10 are diagrams for explaining a swing from an address to a finish by a golfer. The swing includes a fall-through after impact. In the present invention, attention is paid to the characteristics of the swing from address to impact.

  FIGS. 7-10 is the figure which looked at the golfer from the front. The beginning of the swing is the address, and the end of the swing is called the finish. The swing proceeds in the order of (S1), (S2), (S3), (S4), (S5), (S6), (S7), and (S8). In FIG. 7, (S1) is an address, and (S2) is a takeback. (S3) in FIG. 8 is the top (top of swing). Usually, at the top, the moving speed of the head during the swing is minimum. (S4) in FIG. 8 is a downswing. Although (S5) in FIG. 9 is also a downswing, the downswing is more advanced than in (S4) in FIG. (S6) in FIG. 9 is an impact, which is the moment when the head 1a of the golf club 1 and the ball B collide. In FIG. 10, (S7) is a follow-through, and (S8) is a finish. At the finish, the swing ends.

  In the present embodiment, attention is paid to the angular velocity ωy in the cock direction during the downswing from the vicinity of the top to the impact among the various stages of the swing described above, and the angular velocity ωy is subdivided and quantified as time elapses. In the present specification, “near the top” means a time period including a predetermined time immediately before the top and a predetermined time immediately after the top. Specifically, for example, 100 ms from the top −50 ms to the top +50 ms. Means the time zone.

  FIG. 11 shows the relationship between the time (s) from the address to the impact in a certain swing and the angular velocity ωy (deg / s) in the cock direction. In the present embodiment, as shown in FIG. 11, three swing features (1) to (3) are set according to the passage of time of the swing, and each swing feature is quantified.

  The swing feature quantity (1) as the swing feature quantity (a) is the inclination (change amount) of the angular velocity ωy in the cock direction near the top. For example, the angular velocity ωy 50 ms before the top and the angular velocity ωy 50 ms after the top. And the sum. This swing feature quantity (1) has a correlation with the bending stiffness at the measurement point 36 inches from the tip end of the shaft described above.

  The swing feature value (2) as the swing feature value (b) is an average value of the angular velocity ωy from the top to the time point when the angular velocity ωy becomes maximum. The maximum value of the angular velocity ωy from the top to the impact is obtained, and the average value is obtained by dividing the cumulative value of the angular velocity ωy from the top to the time when the maximum value is reached by the time from the top to the time when the maximum value is reached. The value can be determined. This swing feature amount (2) has a correlation with the bending stiffness at the measurement point 26 inches from the tip end of the shaft described above.

  The swing feature value (3) as the swing feature value (c) is an average value of the angular velocity ωy from the top to the impact, and the cumulative value of the angular velocity ωy from the top to the impact is divided by the time from the top to the impact. Thus, the average value can be obtained. This swing feature amount (3) has a correlation with the bending rigidity at the measurement point 6 inches from the tip end of the shaft described above.

  As another swing feature amount, there is an average value of the angular velocity ωy from the time when the angular velocity ωy becomes maximum to the impact. This average value can be obtained by dividing the cumulative value of the angular velocity ωy from the time when the maximum value is reached until the impact by the time from the time when the maximum value is reached until the impact. Although this swing feature amount is not as large as the swing feature amounts (1) to (3), it has been found that there is a correlation with the bending stiffness at the measurement point of 16 inches from the tip end of the shaft. Therefore, it is possible to perform fitting by additionally using this swing feature amount.

  The above swing feature values (1) to (3) are obtained by giving a golfer who desires fitting a predetermined number of balls, for example, five balls, and calculating the average of the swing feature values calculated at the time of each shot. It can be set as a swing feature value.

[Calculation of shaft rigidity per inch]
Next, based on the calculated swing feature values (1) to (3), the shaft rigidity per inch suitable for the golfer is calculated. Prior to this calculation, an approximate expression representing the relationship between the swing feature value and the preferred shaft bending stiffness (EI value) is obtained in advance for each swing feature value. This approximate expression is created based on data collected by having a plurality of testers make trial runs. From the viewpoint of improving the reliability of the approximate expression, it is preferable that the number of testers is large. In the present embodiment, the tester is an intermediate or advanced handicap of 20 or less. For each tester, several golf clubs are selected based on the weight, length, and flex (or tone) of the golf club that is usually used from a plurality of golf clubs (drivers) prepared in advance. Each of several golf clubs was given a test of several balls, for example, six balls (excluding miss shots), and golf clubs that were easy to hit were selected according to the criteria described later.

  Golf clubs that are easy to hit are scored according to the evaluation criteria shown in Table 4 below for the three items of “flying distance”, “direction”, and “easy to swing”, and the total score is 1.5 points or more It is judged that this club is easy to hit. Several selected golf clubs were painted black on the shaft portion and were randomly provided to the testers. This made it impossible for the tester to determine which club is hitting. Trial hits were performed in two sets of 3 balls x number of clubs, and a questionnaire on ease of swinging was asked to check the score each time a 3-ball trial was made for a certain club.

  FIG. 13 is a diagram showing the relationship between the swing feature (3) and the bending stiffness (EI value) at the “6 inch” measurement point created in advance as described above, and FIG. FIG. 15 is a diagram showing the relationship between the swing feature value (2) and the bending rigidity (EI value) at the “26 inch” measurement point created in advance. FIG. It is a figure which shows the relationship between the swing feature-value (1) and the bending rigidity (EI value) in the measurement point of "36 inches".

  In the present embodiment, as shown in FIGS. 13 to 15, although there is a certain correlation between the swing feature value and the bending stiffness at the measurement point per inch, the golfers far from the average group also Considering the fact that there are not a few, instead of expressing the relationship between swing feature quantity and bending stiffness with an approximate expression, at each measurement point, the swing feature quantity is divided into a plurality of ranges and a shaft corresponding to each range. Set the bending stiffness range.

  The number of ranges to be divided for each swing feature amount is not particularly limited in the present invention, and can be appropriately selected within a range of 2 to 4, for example.

For example, the swing feature value (3) related to FIG. 13 is classified as bending stiffness EI (N · m ² ) <24.5 when the swing feature value (3) is 400 (deg / s) or less. When the swing feature value (a) is greater than 400 (deg / s) and less than or equal to 800, it is classified as 23.0 <bending rigidity EI (N · m ² ) <27.5, and the swing feature value (c ) Is greater than 800 (deg / s), it can be classified as bending stiffness EI (N · m ² )> 25.5. The range of bending stiffness is selected so as to slightly overlap with the range of adjacent bending stiffness. In FIG. 13 and FIGS. 14 to 15 to be described later, the unit of EI on the vertical axis is “N · m ² ”, and the value obtained by multiplying the numerical value of the scale by 9.8 is the flexural rigidity (N · m ² ). It becomes.

Further, the swing feature value (2) related to FIG. 14 is classified as bending stiffness EI (N · m ² ) <47.5 when the swing feature value (2) is 550 (deg / s) or less. When the swing feature value (b) is larger than 550 (deg / s), it can be classified as bending rigidity EI (N · m ² )> 42.5.

Further, the swing feature value (1) related to FIG. 15 is classified as bending stiffness EI (N · m ² ) <68.5 when the swing feature value (1) is 360 (deg / s) or less. When the swing feature value (a) is less than 360 (deg / s), the bending rigidity EI (N · m ² )> 60.0 can be classified.

In addition, the present inventor divided the golfers into two groups according to the head speed, and examined the correlation between the swing feature amount and the bending rigidity in each group. We found that the correlation was higher when evaluated in each group.
Therefore, considering the magnitude of the head speed, the above-described range (classification) of the swing feature amount and the bending rigidity can be performed.

  For example, when the golfers are divided into two groups based on the head speed of 45.5 m / s, the range of the swing feature amount and the bending rigidity can be divided as follows.

[Head speed less than 45.5m / s]
For a golfer with a head speed of less than 45.5 m / s, for example, when the swing feature value (3) is 500 (deg / s) or less, the bending stiffness is classified as EI (N · m ² ) <24.5. When the swing feature value (3) is greater than 500 (deg / s) and less than or equal to 800, it is classified as 23.0 <bending rigidity EI (N · m ² ) <26.5, and the swing feature value (3) Can be classified as 25.5 <flexural rigidity EI (N · m ² ) <28.5.

Further, when the swing feature value (2) is 550 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <45.0, and the swing feature value (2) is 550 (deg / s). Can be classified as 42.5 <flexural rigidity EI (N · m ² ) <52.0.

Further, when the swing feature value (1) is 350 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <60.0, and the swing feature value (1) is 350 (deg / s). Can be classified as bending stiffness EI (N · m ² )> 55.5.

[Head speed of 45.5m / s or more]
For golfers with a head speed of 45.5 m / s or more, for example, when the swing feature (3) is 300 (deg / s) or less, the bending rigidity EI (N · m ² ) <24.5 is classified. When the swing feature value (3) is greater than 300 (deg / s) and equal to or less than 550, the swing feature value (3) is classified as 23.0 <bending rigidity EI (N · m ² ) <26.5, and the swing feature value (3) Is larger than 550 (deg / s) and 800 or less, it is classified as 24.0 <bending rigidity EI (N · m ² ) <28.5, and the swing feature (3) is 800 (deg / s). ), It can be classified as 26.0 <bending rigidity EI (N · m ² ).

When the swing feature value (2) is 550 (deg / s) or less, it is classified as 40.0 <bending rigidity EI (N · m ² ) <50.0, and the swing feature value (2) is 550. When it is larger than (deg / s), it can be classified as 42.5 <bending rigidity EI (N · m ² ).

When the swing feature value (1) is 360 (deg / s) or less, it is classified as 51.0 <bending rigidity EI (N · m ² ) <73.0, and the swing feature value (1) is 360. When it is larger than (deg / s), it can be classified as bending stiffness EI (N · m ² )> 64.0.

[Calculation of IFC per inch]
With respect to the range of the EI value of the shaft selected for each inch by the above-described method, for example, the conversion table shown in Tables 1 to 3 is used to select the range corresponding to the 10 stages of IFC. In the present embodiment, as described above, in consideration of the frequency of use and the like, a method of dividing into 10 stages within the range of the shaft prepared by the fitter to be provided to the user is adopted.

For example, if the swing feature value (1) is 450 (deg / s) and the bending rigidity at 36 inches is classified as larger than 60 (N · m ² ) from this value, the range of this range is determined from Table 1. The IFC corresponding to the bending stiffness can be selected to be “4” or more from 60 ÷ 9.8≈6.12. Similarly, when the swing feature value (1) is 300 (deg / s) and the bending stiffness at 36 inches is classified as less than 68.5 (N · m ² ) from this value, from Table 1 The IFC corresponding to the bending rigidity in this range can be selected to be 68.5 / 9.8≈6.99 to “6” or less.

[Selection of shaft]
As described above, the IFC for each inch is calculated for the golfer performing the fitting. Examples of the calculated IFC range include 36 inches: 5 to 9, 26 inches: 0 to 6, and 6 inches: 1 to 7.

  Then, the shaft that most closely matches the calculation result is selected from the database. The database stores data such as IFC for each inch and weight measured in advance for a plurality of types of shafts. As will be described later, when a plurality of shafts are selected, the “matching degree” shown in the following formula (3) is calculated, and the club with the smallest value is proposed to the golfer. As used herein, “degree of coincidence” does not mean the degree of coincidence, but, as is clear from Equation (3), the smaller the value, the closer the shaft has bending rigidity to the calculation result. It is an index that means that. A degree of coincidence of 0 means that the shaft has the same bending rigidity per inch as the calculation result.

  Further, when there are a plurality of shafts having the same degree of coincidence, a plurality of shafts may be proposed to the user, or may be narrowed down to one in consideration of the user's request. As a standard for narrowing down, focusing on ease of swinging, priority is given to a method of giving priority to the degree of IFC coincidence at “36 inches” or “26 inches” on the shaft side, and performance (flight distance, directionality). There is a method of giving priority to the degree of coincidence of IFC in “6 inches” on the shaft tip side.

  Further, in the present embodiment, when selecting based on the above-mentioned “coincidence”, hearing of the weight of my club is performed for a golfer who performs fitting in advance. Based on the result of the hearing, fitting is performed from the shafts within the range of the golf club my club weight ± 5 g from the plurality of shafts stored in the database. If the weight of the golf club with the selected shaft changes significantly compared to the weight of the My Club that we normally use, it will be difficult to take timing and swing, so there is a possibility that the golfer's performance cannot be demonstrated. is there. In order to prevent this reliably, it is preferable to perform fitting from the shaft within the range of the golf club's My Club weight of ± 5 g.

  Hereinafter, a specific example of the selection method will be described with reference to a flowchart. FIG. 16 is a flowchart illustrating an example of the shaft selection process. In this example, when performing the fitting, the selection flow differs depending on whether the golfer attaches importance to performance (flying distance, directionality) or ease of swinging. Priorities are assigned to the swing feature amounts (1) to (3) obtained by trial hits, and shafts are selected according to the priorities. This selection method fits all of the range of bending stiffness of the shaft obtained from each swing feature amount from among the multiple shafts whose bending stiffness at three positions corresponding to the three swing feature amounts has been measured in advance. This is particularly effective when there is no shaft to perform.

First, in step S1, the length and weight of the my club that the golfer performing the fitting usually uses are confirmed. As described above, in order to prevent the golfer from failing to perform, the fitting is performed from the shaft within the range of the golf club's My Club weight ± 5 g. In order to improve the fitting accuracy, if the length of the user's My Club is different from the length of the golf club based on the shaft stored in the database, the total club weight equivalent to the club length prepared in the database The shaft that matches the user is selected. For example, if the length of a club stored in the database is 45 inches and the user's club length A (mm) is different from 45 inches (= 1143 mm), the total weight of the club swinging for measurement is calculated. The fitting is performed by changing to the one calculated by the following formula (total weight corresponding to 45 inches).
(Total club weight used for measurement) = (A-1143) × 0.377 + (total club weight of my club)

  Next, in step S2, it is checked whether the item that the golfer attaches importance to fitting is performance or ease of swinging. If the golfer places importance on ease of swinging, the process proceeds to step S3. On the other hand, if the golfer places importance on performance, the process proceeds to step S6.

In step S3, the bending stiffness EI (N · m ² ) at a location 36 inches from the tip end of the shaft is determined from the swing feature value (1). When the swing feature value (1) is 360 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <68.5, and the swing feature value (1) is more than 360 (deg / s). If it is large, it is classified as bending rigidity EI (N · m ² )> 60.0. Then, a range of IFC values corresponding to the classified bending stiffness range is selected according to Table 1. The shaft within the selected IFC range is then squeezed. If the shaft is narrowed down to one by the selection in step S1 and the classification and narrowing in step S3, it is assumed that the fitting is not good, and the fitting is finished in this step S3. After confirming and changing the conditions, the fitting is performed again. I do. Also in the following Steps S4 to S8, the IFC value range corresponding to the classified bending stiffness range is selected according to Tables 1 to 3, as in Step S3. The shaft within the selected IFC range is then squeezed.

In step S4, the bending stiffness EI (N · m ² ) at a location 26 inches from the tip end of the shaft is determined from the swing feature value (2). When the swing feature value (2) is 550 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <47.5, and the swing feature value (2) is more than 550 (deg / s). If it is large, it is classified as bending rigidity EI (N · m ² )> 42.5. When the shaft is narrowed down to one by the selection in step S1 and the classification in steps S3 to S4, the fitting ends in this step S4.

In step S5, the bending stiffness EI (N · m ² ) at a location 6 inches from the tip end of the shaft is determined from the swing feature value (3). When the swing feature value (3) is 400 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (3) is more than 400 (deg / s). In the case of large 800 or less, it is classified as 23.0 <bending rigidity EI (N · m ² ) <27.5, and when the swing feature value (3) is larger than 800 (deg / s), the bending rigidity EI Classify as (N · m ² )> 25.5.

On the other hand, in step S6 when emphasizing performance, unlike the case where emphasis is placed on ease of swinging, first, the bending stiffness EI (N · m ² ) at a location 6 inches from the tip end of the shaft is determined as a swing feature (3). Determine from. When the swing feature value (3) is 400 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (3) is more than 400 (deg / s). In the case of large 800 or less, it is classified as 23.0 <bending rigidity EI (N · m ² ) <27.5, and when the swing feature value (3) is larger than 800 (deg / s), the bending rigidity EI Classify as (N · m ² )> 25.5. If the shaft is narrowed down to one by the selection in step S1 and the classification and narrowing down in step S6, it is assumed that the fitting is not good, and the fitting is finished in this step S6, and after confirming and changing the conditions, the fitting is performed again. I do.

In step S7, the bending stiffness EI (N · m ² ) at a location 36 inches from the tip end of the shaft is determined from the swing feature value (1). When the swing feature value (1) is 360 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <68.5, and the swing feature value (1) is more than 360 (deg / s). If it is large, it is classified as bending rigidity EI (N · m ² )> 60.0. If the shaft is narrowed down to one by the selection in step S1 and the classification in steps S6 to S7, the fitting ends in this step S4.

In step S8, the bending stiffness EI (N · m ² ) at a location 26 inches from the tip end of the shaft is determined from the swing feature value (2). When the swing feature value (2) is 550 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <47.5, and the swing feature value (2) is more than 550 (deg / s). If it is large, it is classified as bending rigidity EI (N · m ² )> 42.5.

  When a plurality of shafts are selected through step S5 or step S8, the “coincidence” is calculated according to the above-described equation (3), and the shaft with the smallest coincidence is selected. In this case, the IFC selected in steps S3 to S8 ranges from a certain value to a certain value. Therefore, using the intermediate value in this range, the degree of coincidence can be calculated according to Equation (3).

  FIG. 17 is a flowchart showing an example of the shaft selection process when the head speed is small (less than 45.5 m / s).

  First, in step S11, as in step S1 in the selection process shown in FIG. 16 described above, the length and weight of the my club normally used by the golfer performing the fitting are confirmed. Then, fitting is performed from the shaft within the range of club weight ± 5 g converted to 45 inches.

  Next, in step S12, it is confirmed whether the item that the golfer attaches importance to fitting is performance or ease of swinging. If the golfer places importance on ease of swinging, the process proceeds to step S13. On the other hand, if the golfer places importance on performance, the process proceeds to step S16.

In step S13, the bending stiffness EI (N · m ² ) at a location 36 inches from the tip end of the shaft is determined from the swing feature value (1). When the swing feature value (1) is 350 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <60.0, and the swing feature value (1) is more than 350 (deg / s). When it is large, it is classified as bending rigidity EI (N · m ² )> 55.5. Then, a range of IFC values corresponding to the classified bending stiffness range is selected according to Table 1. The shaft within the selected IFC range is then squeezed. If the shaft is narrowed down to one by the selection in step S11 and the classification and narrowing in step S13, it is determined that the fitting is not successful, and the fitting ends in this step S13, and after confirming and changing the conditions, the fitting is performed again. I do. Also in the following steps S14 to S18, the IFC value ranges corresponding to the classified bending stiffness ranges are selected according to Tables 1 to 3, as in step S13. The shaft within the selected IFC range is then squeezed.

In step S14, the bending stiffness EI (N · m ² ) at a location 26 inches from the tip end of the shaft is determined from the swing feature value (2). When the swing feature value (2) is 550 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <45.0, and the swing feature value (2) is more than 550 (deg / s). When larger, it is classified as 42.5 <bending rigidity EI (N · m ² ) <52.0. If the shaft is narrowed down to one by the selection in step S11 and the classification in steps S13 to S14, the fitting ends in this step S14.

In step S15, the bending stiffness EI (N · m ² ) at a position 6 inches from the tip end of the shaft is determined from the swing feature value (3). When the swing feature value (3) is 500 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (3) is more than 500 (deg / s). If it is large and 800 or less, it is classified as 23.0 <bending rigidity EI (N · m ² ) <26.5, and if the swing feature (3) is larger than 800 (deg / s), 25. 5 <Bending rigidity EI (N · m ² )

On the other hand, in step S16 when emphasizing performance, unlike when emphasizing ease of swinging, first, the bending stiffness EI (N · m ² ) at a position 6 inches from the tip end of the shaft is determined as a swing feature (3). Determine from. When the swing feature value (3) is 500 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (3) is more than 500 (deg / s). If it is large and 800 or less, it is classified as 23.0 <bending rigidity EI (N · m ² ) <26.5, and if the swing feature (3) is larger than 800 (deg / s), 25. 5 <Bending rigidity EI (N · m ² ) If the shaft is narrowed down to one by the selection in step S11 and the classification and narrowing in step S16, the fitting is not successful, the fitting ends in this step S16, the condition is confirmed / changed, and the fitting is performed again. I do.

In step S17, the bending stiffness EI (N · m ² ) at a location 36 inches from the tip end of the shaft is determined from the swing feature (1). When the swing feature value (1) is 350 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <60.0, and the swing feature value (1) is larger than 350 (deg / s). The case is classified as bending stiffness EI (N · m ² )> 55.5. If the shaft is narrowed down to one by the selection in step S11 and the classification in steps S16 to S17, the fitting ends in this step S17.

In step S18, the bending stiffness EI (N · m ² ) at a location 26 inches from the tip end of the shaft is determined from the swing feature value (2). When the swing feature value (2) is 550 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <45.0, and the swing feature value (2) is more than 550 (deg / s). When larger, it is classified as 42.5 <bending rigidity EI (N · m ² ) <52.0.

  When a plurality of shafts are selected through step S15 or step S18, the “coincidence” is calculated according to the above-described equation (3), and the shaft with the smallest coincidence is selected. In this case, the IFC selected in steps S13 to S18 ranges from a certain value to a certain value. Therefore, using the intermediate value in this range, the degree of coincidence can be calculated according to Equation (3).

  FIG. 18 is a flowchart showing an example of the shaft selection process when the head speed is high (45.5 m / s or more).

  First, in step S21, as in step S1 in the selection process shown in FIG. 16 described above, the length and weight of the my club normally used by the golfer performing the fitting are confirmed. Then, fitting is performed from the shaft within the range of club weight ± 5 g converted to 45 inches.

  In step S22, it is checked whether the item that the golfer attaches importance to fitting is performance or ease of swinging. If the golfer places importance on ease of swinging, the process proceeds to step S23. On the other hand, if the golfer places importance on performance, the process proceeds to step S26.

In step S23, the bending stiffness EI (N · m ² ) at a location 36 inches from the tip end of the shaft is determined from the swing feature value (1). When the swing feature value (1) is 360 (deg / s) or less, it is classified as 51.0 <bending rigidity EI (N · m ² ) <73.0, and the swing feature value (1) is 360 (deg). / S), it is classified as bending stiffness EI (N · m ² )> 64.0. Then, a range of IFC values corresponding to the classified bending stiffness range is selected according to Table 1. The shaft within the selected IFC range is then squeezed. If the shaft is narrowed down to one by the selection in step S21 and the classification and narrowing in step S23, it is assumed that the fitting is not successful, and the fitting is finished in this step S23, and after confirming / changing the conditions, the fitting is performed again. I do. Also in the following steps S24 to S28, the IFC value range corresponding to the classified bending stiffness range is selected according to Tables 1 to 3, as in step S23. The shaft within the selected IFC range is then squeezed.

In step S24, the bending rigidity EI (N · m ² ) at a location 26 inches from the tip end of the shaft is determined from the swing feature value (2). When the swing feature value (2) is 550 (deg / s) or less, it is classified as 40.0 <bending rigidity EI (N · m ² ) <50.0, and the swing feature value (2) is 550 (deg). / S), it is classified as 42.5 <bending rigidity EI (N · m ² ). If the shaft is narrowed down to one by the selection in step S21 and the classification in steps S23 to S24, the fitting ends in this step S24.

In step S25, the bending stiffness EI (N · m ² ) at a position 6 inches from the tip end of the shaft is determined from the swing feature value (3). When the swing feature value (3) is 300 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (3) is more than 300 (deg / s). In the case of large 550 or less, it is classified as 23.0 <bending rigidity EI (N · m ² ) <26.5, and when the swing feature value (3) is larger than 550 (deg / s) and 800 or less. 24.0 <bending rigidity EI (N · m ² ) <28.5, and when the swing feature value (3) is greater than 800 (deg / s), 26.0 <bending rigidity EI ( N · m ² ).

On the other hand, in step S26 when performance is emphasized, unlike the case where emphasis is placed on ease of swinging, first, the bending stiffness EI (N · m ² ) at a location 6 inches from the tip end of the shaft is determined as a swing feature (3). Determine from. When the swing feature value (3) is 300 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (3) is more than 300 (deg / s). In the case of large 550 or less, it is classified as 23.0 <bending rigidity EI (N · m ² ) <26.5, and when the swing feature value (3) is larger than 550 (deg / s) and 800 or less. 24.0 <bending rigidity EI (N · m ² ) <28.5, and when the swing feature value (3) is greater than 800 (deg / s), 26.0 <bending rigidity EI ( N · m ² ). If the shaft is narrowed down to one by the selection in step S21 and the classification or narrowing in step S26, it is determined that the fitting is not successful, and the fitting ends in this step S26, and after confirming and changing the conditions, the fitting is performed again. I do.

In step S17, the bending stiffness EI (N · m ² ) at a location 36 inches from the tip end of the shaft is determined from the swing feature (1). When the swing feature value (1) is 360 (deg / s) or less, it is classified as 51.0 <bending rigidity EI (N · m ² ) <73.0, and the swing feature value (1) is 360 (deg). / S), the bending stiffness is classified as EI (N · m ² )> 64.0. When the shaft is narrowed down to one by the selection in step S21 and the classification in steps S26 to S27, the fitting ends in this step S27.

In step S28, the bending stiffness EI (N · m ² ) at a location 26 inches from the tip end of the shaft is determined from the swing feature value (2). When the swing feature value (2) is 550 (deg / s) or less, it is classified as 40.0 <bending rigidity EI (N · m ² ) <50.0, and the swing feature value (2) is 550 (deg). / S), it is classified as bending rigidity EI (N · m ² )> 42.5.

  When a plurality of shafts are selected through step S25 or step S28, the “coincidence” is calculated according to the above-described equation (3), and the shaft with the smallest coincidence is selected. In this case, the IFC selected in steps S23 to S28 ranges from a certain value to a certain value. Therefore, using the intermediate value in this range, the degree of coincidence can be calculated according to Equation (3).

〔inspection result〕
A shaft exchange type golf club capable of freely changing the shaft was produced, and the effectiveness of the fitting method according to the present embodiment was verified using this golf club.

  Experiments were conducted on single equivalent testers using S or X shafts. The number of testers was 17, and the head speed was about 41 to 51 m / s.

  First, a golf ball having a sensor attached to a grip is used for trial hitting, a swing feature amount of the tester is measured, and a single shaft having a bending rigidity matching the tester is calculated from the swing feature amount in a database. Determined from. This database stores data of 59 shafts for which IFC for each inch has been calculated in advance.

  Next, among the 59 shafts, the tester used 5 shafts within the tester My Club ± 5 g and different shaft characteristics (flex, tone). As shown in FIG. 19, the five shafts have a soft and medium tone, a soft and medium tone, a medium tone with a medium hardness, and a soft and medium tone. And a soft and handy characteristic. A shaft having the characteristics of these five patterns was prepared according to weight.

  As a result of the test hit, if there is a large flight distance, the ball does not bend, and one of the five easy-to-swing clubs is present, whether or not a shaft close to the shaft characteristics of the club has been selected exists. In this case, whether the selected shaft is included in the ellipse including those shafts (see the hatched portion in FIG. 19) or whether it exists in the vicinity is used as an evaluation criterion.

  FIG. 20 is a diagram showing an example of the verification result. FIG. 20A shows that the selected club G is within the box surrounded by a broken line, indicating that the fitting is appropriate, and FIG. 20B shows the selected club. Is out of the dashed box, indicating that the fitting was not appropriate.

  For 17 testers, the case where the fitted club was included in the ellipse was defined as “correct”. The results confirmed that 15 out of 17 testers were correctly fitted. The accuracy rate was (15/17) × 100≈88%. And about 15 persons who had an effect (it was a correct answer), it was confirmed how much effect it had regarding flight distance, directionality, and ease of swinging. As an average value of 15 people, it was confirmed that the flight distance was increased by 5.1 yards, the directionality was 7.4 yards toward the center, and the ease of swinging was improved by 1.7 points. Note that the evaluation of ease of swinging is based on a nine-level evaluation ("5" is neither), as shown in FIG.

  It should be noted that the embodiment disclosed this time is merely an example in all respects and is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Golf club 2 Sensor 2a Casing 10 Computer (data analysis device)
20 Shaft 20a Tip end 20b Butt end G Golfer B Ball

Claims (10)

A method for fitting a shaft of a golf club, which selects a shaft that matches the golfer based on a golfer's swing,
Hitting a golf ball with a golf club having a sensor capable of measuring angular velocities around three axes attached to the grip to obtain a measured value from the sensor;
Determining an address, top and impact in the swing from the measured values;
Selecting a shaft that matches the golfer using at least two of the following swing feature quantities (a) to (c) obtained from the measurement values:
(A) to (c) are selected to correspond to the bending rigidity of the shaft at three positions of 36 inches, 26 inches and 6 inches from the tip end of the shaft, respectively.
Based on the relationship between each of the swing feature values (a) to (c) and the bending rigidity of the shaft, which were created in advance by trial hits, the swing feature values are divided into a plurality of ranges for each position, and each range is supported. And set the range of bending rigidity of the shaft,
From the measured value, a range of the bending stiffness of the shaft at a position corresponding to the at least two swing feature values among three positions of 36 inches, 26 inches, and 6 inches from the tip end of the shaft is obtained.
A shaft that matches the golf club is selected from a plurality of shafts whose bending rigidity at the three positions has been measured in advance, based on a range of the bending rigidity of the shaft at at least two acquired positions. , Golf club shaft fitting method.
(A) Amount of change in grip angular velocity in the cock direction near the top (b) Average value of grip angular velocity in the cock direction from the top until the grip angular velocity in the cock direction reaches the maximum during the downswing (c ) Average grip angular velocity in the cock direction from top to impact For each of the bending stiffnesses at the three positions, any one of a plurality of rank values is given according to the acquired bending stiffness value,
Rank values at three assigned positions from among a plurality of shafts to which any one of a plurality of rank values is assigned according to the measured bending stiffness values at the three positions. The method of fitting a shaft of a golf club according to claim 1, wherein a shaft that matches a golfer is selected based on the golf ball. When the swing feature value (a) is 360 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <68.5, and the swing feature value (a) is 360 (deg / s). Bend rigidity EI (N · m ² )> 60.0,
When the swing feature value (b) is 550 (deg / s) or less, it is classified as bending rigidity EI (N · m ² ) <47.5, and the swing feature value (b) is 550 (deg / s). Is larger, the bending stiffness is classified as EI (N · m ² )> 42.5, and
When the swing feature value (c) is 400 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (a) is more than 400 (deg / s). In the case of large 800 or less, it is classified as 23.0 <bending rigidity EI (N · m ² ) <27.5, and the bending rigidity EI when the swing feature value (c) is larger than 800 (deg / s). The golf club shaft fitting method according to claim 1, wherein the golf club shaft is classified as (N · m ² )> 25.5.   When selecting a shaft that matches a golfer using the three swing feature values, each swing feature is selected from a plurality of shafts whose bending stiffnesses at three positions corresponding to the three swing feature values are measured in advance. If there is no shaft that fits all of the bending stiffness range of the shaft obtained from the amount, the fitting of the bending stiffness range of the shaft obtained from the swing feature amount of (c), the swing feature of (a) The shaft is selected in accordance with the priority order of the bending rigidity range of the shaft obtained from the amount and the conforming range of the bending rigidity of the shaft obtained from the swing characteristic amount of (b). Golf club shaft fitting method.   When selecting a shaft that matches a golfer using the three swing feature values, each swing feature is selected from a plurality of shafts whose bending stiffnesses at three positions corresponding to the three swing feature values are measured in advance. When there is no shaft that fits all of the bending stiffness range of the shaft obtained from the quantity, the fitting of the bending stiffness range of the shaft obtained from the swing feature quantity of (a), the swing feature of (b) The shaft is selected according to the priority order of the bending rigidity range of the shaft acquired from the amount and the matching order of the bending rigidity range of the shaft acquired from the swing characteristic amount of (c). Golf club shaft fitting method. For golfers whose head speed is less than 45.5 m / s,
When the swing feature value (a) is 350 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <60.0, and the swing feature value (a) is from 350 (deg / s). Bend rigidity EI (N · m ² )> 55.5,
When the swing feature value (b) is 550 (deg / s) or less, it is classified as bending rigidity EI (N · m ² ) <45.0, and the swing feature value (b) is 550 (deg / s). Is also larger than 42.5 <bending rigidity EI (N · m ² ) <52.0, and
When the swing feature value (c) is 500 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (c) is more than 500 (deg / s). If the swing feature value (c) is greater than 800 (deg / s) when the swing characteristic amount (c) is greater than 800 (deg / s), the load characteristic is classified as 23.0 <bending rigidity EI (N · m ² ) <26.5. ^2. The golf club shaft fitting method according to claim 1, wherein 5 <bending rigidity EI (N · m ² ) <28.5 is classified. For golfers with a head speed of 45.5 m / s or more,
When the swing feature value (a) is 360 (deg / s) or less, the swing feature value (a) is classified as 51.0 <bending rigidity EI (N · m ² ) <73.0, and the swing feature value (a) is 360 ( deg / s), it is classified as bending stiffness EI (N · m ² )> 64.0,
When the swing feature value (b) is 550 (deg / s) or less, it is classified as 40.0 <bending rigidity EI (N · m ² ) <50.0, and the swing feature value (b) is 550 ( deg / s), it is classified as 42.5 <bending rigidity EI (N · m ² ), and
When the swing feature value (c) is 300 (deg / s) or less, it is classified as bending stiffness EI (N · m ² ) <24.5, and the swing feature value (c) is more than 300 (deg / s). If the swing feature value (c) is greater than 550 (deg / s) and less than or equal to 800, it is classified as 23.0 <bending rigidity EI (N · m ² ) <26.5. 24.0 <bending rigidity EI (N · m ² ) <28.5, and when the swing feature (c) is greater than 800 (deg / s), 26.0 <bending rigidity EI ( The golf club shaft fitting method according to claim 1, wherein the method is classified as N · m ² ).   When selecting a shaft that matches a golfer using the three swing feature values, each swing feature is selected from a plurality of shafts whose bending stiffnesses at three positions corresponding to the three swing feature values are measured in advance. If there is no shaft that fits all of the bending stiffness range of the shaft obtained from the amount, the fitting of the bending stiffness range of the shaft obtained from the swing feature amount of (c), the swing feature of (a) The shaft is selected according to the priority order of the bending rigidity range of the shaft acquired from the amount and the matching order of the bending rigidity range of the shaft acquired from the swing characteristic amount of (b). A method for fitting a shaft of the described golf club.   When selecting a shaft that matches a golfer using the three swing feature values, each swing feature is selected from a plurality of shafts whose bending stiffnesses at three positions corresponding to the three swing feature values are measured in advance. When there is no shaft that fits all of the bending stiffness range of the shaft obtained from the quantity, the fitting of the bending stiffness range of the shaft obtained from the swing feature quantity of (a), the swing feature of (b) The shaft is selected in accordance with the priority order of the bending rigidity range of the shaft obtained from the amount and the conforming range of the bending rigidity range of the shaft obtained from the swing characteristic amount of (c). A method for fitting a shaft of the described golf club.   When the length of the golf club of the user is different from the length of the golf club having a shaft selected from the plurality of shafts, the total weight of the golf club is changed based on a difference between the two lengths. The golf club shaft fitting method according to any one of claims 1 to 9.

Images