METHOD OF EVALUATING A GOLF CLUB

• US 20110028248A1
• Filed: 07/30/2010
• Published: 02/03/2011
• Est. Priority Date: 07/31/2009
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Dunlop Sports Co. Ltd. (Sumitomo Rubber Industries Limited)
• Inventors: UEDA, Masahiko
• Granted Patent: US 8,475,300 B2
• Time in Patent Office: Days
• US Class Current: 473/409
• CPC Class Codes: A63B 2024/0009 Computerised real time comparison with previous movements or motion sequences of the user
• CPC Class Codes: A63B 2024/0028 Tracking the path of an object, e.g. a ball inside a soccer pitch
• CPC Class Codes: A63B 2024/0056 for statistical or strategic analysis
• CPC Class Codes: A63B 2024/0068 Comparison to target or threshold, previous performance or not real time comparison to other individuals
• CPC Class Codes: A63B 2071/0647 Visualisation of executed movements
• CPC Class Codes: A63B 2220/58 Measurement of force related parameters by electric or magnetic means
• CPC Class Codes: A63B 2220/62 Time or time measurement used for time reference, time stamp, master time or clock signal
• CPC Class Codes: A63B 2220/806 Video cameras
• CPC Class Codes: A63B 69/3605 Golf club selection aids informing player of his average or expected shot distance for each club
• CPC Class Codes: A63B 69/3614 using electro-magnetic, magnetic or ultrasonic radiation emitted, reflected or interrupted by the golf club
• CPC Class Codes: A63B 69/3632 Clubs or attachments on clubs, e.g. for measuring, aligning A63B69/3614 takes precedence; clubs for swinging exercises in general A63B15/00

Abstract

A method of evaluating a golf club is disclosed. The method includes a step (St1) of determining motions of the golf club during a swinging motion of a golf player including a period ranging from a time (Ts) to a time (Tf); a step (St2) of obtaining in a time series power index values (Pw) during the period ranging from the time (Ts) to the time (Tf), based on the result of the determination; a step (St3) of obtaining a power integration value (Sp) by integrating the power index values (Pw) during the period ranging from the time (Ts) to the time (Tf); a step (St4) of calculating club energy (Eg) of the golf club at the time (Tf); and a step (St5) of quantitatively evaluating club suitability based on the power integration value (Sp) and the club energy (Eg). Each of the power index values (Pw) is a value which is correlated to a power of a work provided from the golf player to the golf club.

Claims

1. A method of evaluating a golf club comprising the steps of:

a step (St1) of determining motions of the golf club during a swinging motion of a golf player including a period ranging from a time (Ts) to a time (Tf);

a step (St2) of obtaining power index values (Pw) in a time series during the period ranging from the time (Ts) to the time (Tf), based on the result of the determination;

a step (St3) of obtaining a power integration value (Sp) by integrating the power index values (Pw) during the period ranging from the time (Ts) to the time (Tf);

a step (St4) of calculating club energy (Eg) of the golf club at the time (Tf); and

a step (St5) of quantitatively evaluating club suitability based on the power integration value (Sp) and the club energy (Eg);

wherein each of the power index values (Pw) is a value which is correlated to power of a work provided from the golf player to the golf club.

2. The method according to claim 1, wherein the club suitability is evaluated based on a ratio (Sp/Eg) of the power integration value (Sp) relative to the club energy (Eg).

3. The method according to claim 1, wherein the power index value (Pw) is calculated according to the Equation (1) as below:

Pw=M·

({umlaut over (r)}−

g)·

{dot over (r)}+Tg·

ω

 

 

(1)

where, in the equation (1), “

M”

is a weight of the golf club;

“

{umlaut over (r)}”

(with two dots appended thereto) is an acceleration of the center of gravity of the golf club;

“

g”

is an acceleration of gravity;

“

{dot over (r)}”

(with one dot appended thereto) is a velocity of the center of gravity of the golf club;

“

Tg”

is a torque acting around a rotation axis (Z1) extending perpendicularly to a virtual swinging plane (PL1) and passing through the golf grip; and

“

ω

”

is an angular velocity of the golf grip.

4. The method according to claim 1, wherein the club energy (Eg) is a sum of the values (E1) and (E2) as below:

(E1);

kinetic energy of the golf club or an approximate value thereof; and

(E2);

rotation energy of the golf club or an approximate value thereof.

5. The method according to claim 1, wherein the time (Tf) is a time when the golf club impacts on a golf ball.

6. The method according to claim 1, wherein the time (Ts) is a time when the golf club is positioned adjacent a top-of-the-swing thereof.

7. The method according to claim 1, wherein during the step (St1), the determination is effected with using a motion capturing system.

8. The method according to claim 7, wherein the motion capturing system has a plurality of cameras, a plurality of markers attached to the golf club, and a data analyzing device;

and wherein the number of the markers ranges from 3 to 10.

9. The method according to claim 8, wherein the markers are provided to the grip, the head and the shaft;

and wherein the golf club includes two markers which are apart from each other at a distance no less than 30 mm.

10. The method according to claim 7, wherein the motion capturing system has a plurality of cameras, a plurality of marks attached to the golf club, and a data analyzing device;

and wherein the number of the marks ranges from 3 to 10.

11. The method according to claim 10, wherein the marks are provided to the grip, the head and the shaft;

and wherein the golf club includes two marks which are apart from each other at a distance no less than 30 mm.

12. The method according to claim 1, wherein the power index value (Pw) is a sum of values (a) and (b) as below:

(a);

a power index value (Pw A) related to a translational motion of the golf club; and

(b);

a power index value (Pw B) related to a rotational motion of the golf club.

13. The method according to claim 1, wherein during the step (St1), the determination is effected as three-dimensional data;

and wherein during the step (St2), the three-dimensional data are converted to use them as two-dimensional data.

14. The method according to claim 1, wherein a three-dimensional determination system is used during the step (St1);

and wherein the step (St2) includes a step (St22) in which a posture of a shaft of the golf club is calculated at each of the times, based on a three-dimensional coordinate obtained by the three-dimensional determination system.

15. The method according to claim 1, wherein a three-dimensional determination system is used during the step (St1);

and wherein the step (St2) includes a step (St23) in which an acceleration value at a center of gravity of the golf club is calculated at each of the times, based on a three-dimensional coordinate obtained by the three-dimensional determination system.

16. The method according to claim 15, wherein during the step (St23), the acceleration value at the center of gravity of the golf club is calculated based on the three-dimensional coordinate of a grip of the golf club.

17. The method according to claim 15, wherein the step (St2) includes a step (St24) in which a torque (Tg) acting at the grip is calculated based on the calculated acceleration value at center of gravity.

18. The method according to claim 1,

wherein when the power index values (Pw) are calculated during the step (St2), an approximate rotation axis of the golf club is set;

wherein the approximate rotation axis is an axis extending perpendicularly to a virtual swinging plane (PL1); and

wherein the virtual swinging plane (PL1) is obtained by approximating the data of the swinging motion determined during the step (St1).

19. A method of evaluating a golf club comprising the steps of:

a step (Stp1) of determining motions of the golf club during a swinging motion of a golf player at least one time (Tt1);

a step (Stp2) of obtaining a power index value (Pw) at least at one time (Tt2) during the swinging motion, based on the result of the determination

a step (Stp3) of calculating club energy (Eg) of the golf club at the time (Tt2); and

a step (Stp4) of quantitatively evaluating club suitability based on the power index value (Pw) and the club energy (Eg),

wherein the power index value (Pw) is a value which is correlated to a power of a work provided from the golf player to the golf club.

20. The method according to claim 19, wherein the time (Tt2) is period ranging from 0.15 second prior to an impact of the golf club on a golf ball, to 0.15 second after the impact.