Method and apparatus for measuring aerodynamic characteristics of a golf ball

• US 6,286,364 B1
• Filed: 09/17/1999
• Issued: 09/11/2001
• Est. Priority Date: 09/18/1998
• Status: Expired due to Term

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Costa, George, Gobush, William, Days, Charles A., Aoyama, Steven, Pelletier, Diane I.
• Primary Examiner(s): NOORI, MAX H
• Application Number:
  US09/397,497
• Time in Patent Office: 725 Days
• Field of Search: 73/650.3, 473/140, 473/152, 473/156, 473/198, 473/199
• US Class Current: 73/65.03
• CPC Class Codes: A63B 43/008 with means for improving visibility, e.g. special markings or colours illuminating or reflecting means A63B43/06
• CPC Class Codes: A63B 69/3614 using electro-magnetic, magnetic or ultrasonic radiation emitted, reflected or interrupted by the golf club
• CPC Class Codes: G01P 3/366 by using diffraction of light for measuring speed of fluids G01P5/26
• CPC Class Codes: G01P 3/38 using photographic means
• CPC Class Codes: G01P 3/44 for measuring angular speed G01P3/56 takes precedence
• CPC Class Codes: G01P 3/56 for comparing two speeds

Abstract

A method and a system for measuring the spin decay rate of a golf ball. The system includes an indoor testing area, a launching device, and a measuring device positioned at a final position along the ball'"'"'s flight path. When the ball is launched by the launching device, the measuring device measures the spin rate and speed at the final position. Then, the launching device can launch the ball at the speed and spin rate of the final position and a new final speed and spin rate are measured again. The spin rate difference from launching to the final position is used to determine the spin decay rate. By using discrete spin decay rate measurements, the spin decay rate profile of a golf ball during its entire flight can be measured in the indoor area.

Claims

1. A method of determining a spin decay rate of a golf ball along a flight path, wherein the method comprises the steps of:

a. providing a launching device for launching the golf ball along the flight path at an initial speed and initial spin rate;

b. launching the golf ball along the flight path at the initial speed and the initial spin rate;

c. measuring a final spin rate at a final position spaced from the launching device, wherein the step of measuring further includes taking two images of the ball at the final position;

d. timing the flight of the ball from the launching to the final position; and

e. determining the spin decay rate using the images at the final position.

6. The method of claim 1, wherein the step of determining the spin decay rate further includes automatically calculating the spin decay rate from the images.

21. The system of claim 1, wherein the initial speed and the initial spin rate are known at launching the golf ball, wherein the step of determining the spin decay rate further includes using the initial speed and the initial spin rate.

2. A method of determining a spin decay rate of a golf ball along a flight path, wherein the method comprises the steps of:

a. providing a launching device for launching the golf ball along the flight path;

b. repeatedly launching the golf ball along the flight path at a plurality of different initial speeds and spin rates;

c. after each launching measuring a final spin rate at a final position spaced from the launching device, wherein the step of measuring further includes taking two images of the ball at the final position, where the first initial spin rate equals a predetermined value and each subsequent initial spin rate equals the previous final spin rate;

d. timing the flight of the ball from the launching to the final position;

e. determining the spin decay rate using the images at the final position; and

f. combining the spin decay rates for each launching to form the spin decay rate profile for the ball along the flight path.

3. The method of claim 2, wherein the step of measuring further includes measuring at least one intermediate spin rate at an associated intermediate position spaced between the launching device and the final position;

and the step of timing further including timing the flight of the ball from the first intermediate position to the final position for each launching; and

the step of determining the spin decay rate for each launching further including using the images at the intermediate and final positions for each launching.

4. The method of claim 3, further including measuring at least two intermediate spin rates at at least two intermediate positions spaced from the launching device and one another;

after each launching, measuring a final spin rate at a final position spaced further from the launching device than the intermediate positions, where the first initial spin rate equals a predetermined value and each subsequent initial spin rate equals the previous final spin rate;

timing the flight of the ball from the first intermediate position to second intermediate position;

timing the flight of the ball from the second intermediate position to the final position for each launching;

determining the spin decay rate for each launching using the intermediate spin rates and the final spin rate for each launching; and

combining the spin decay rates for each launching to form the spin decay rate profile for the ball along the flight path.

5. The method of claim 3, wherein the step of measuring the intermediate and final spin rates further includes taking two images of the ball at the intermediate and final positions.

7. A system for measuring a spin decay rate for a golf ball along a flight path having a plurality of flight intervals, wherein the system comprises:

a launching device for launching the golf ball along the flight path at an initial spin rate;

a timer for measuring a time interval for the flight of the golf ball between a first position and a spaced second position; and

a first measuring device located at the first position for determining a first spin rate of the golf ball at the first position; and

a computer for using the first spin rate to determine the spin decay rate for at least one flight interval.

8. The system of claim 7, further including a second measuring device located at the second position for determining a second spin rate of the golf ball at the second position;

wherein the first and second spin rates and the time interval are used to determine the spin decay rate for at least one flight interval.

9. The system of claim 8, wherein the first and second spin rates and the time interval are used to determine the spin decay rate for all of the flight intervals.

10. The system of claim 8, further including a timer actuator coupled to the timer, so that when the golf ball is in flight the timer starts when the golf ball reaches the first position and stops when the golf ball reaches the second position.

11. The system of claim 10, further including a third measuring device located at a third position for determining a third spin rate of the golf ball at the third position, so that the spin decay rate is determined between the first and second positions and between the second and third positions.

12. The system of claim 8, wherein the first and second positions form a line parallel to the flight path.

13. The system of claim 8, wherein the launching device includes two belts for launching the golf ball.

14. The system of claim 10, wherein each measuring device further includes a movable tower and a monitor supported by the tower.

15. The system of claim 14, wherein each tower further includes a frame and a platform movable vertically on the frame, said platform supports the associated monitor and allows the platform to be vertically adjustable.

16. The system of claim 14, wherein the timer actuator further includes two pairs of light beams and sensors, the first pair of light beams and sensors being coupled to the tower at the first position and the second pair of light beams and sensors being coupled to the tower at the second position;

wherein the first sensors send a signal to the timer to start and the second sensors send a signal to the timer to stop.

17. The system of claim 14, wherein each monitor further includes:

a support structure;

a first light-reflecting element disposed on the support structure;

a lighting unit disposed on the support structure and directing light into a predetermined field-of-view along the flight path of the ball;

a first camera unit disposed on the support structure and pointed toward the predetermined field-of-view to create at least two images of the golf ball while moving in the predetermined field-of-view; and

computer to control the system and determine the flight characteristics of the golf ball from said images.

18. The system of claim 17, wherein the computer includes means for determining the first spin rate of the golf ball from the images at the first position and the second spin rate of the golf ball from the images at the second position.

19. The system of claim 18, wherein the computer includes means for determining the spin decay rate from the first spin rate and the second spin rate.

20. The system of claim 19, wherein the computer further includes the timer.

22. The system of claim 14, wherein the first measuring device is a monitor for taking at least two images of the golf ball, the first spin rate is determined using the images.