Measurement of the coefficient of restitution of a golf club
AssigneeCallaway Golf Company
InventorsMatthew J. Erickson, Pin Fan, Steven M. Ehlers, John B. Kosmatka
Life of this patent
Estimating the term…
Abstract
A method (100) and system (20) for predicting a coefficient of restitution (COR) of a golf club (30) or golf club head (36) is disclosed herein. The system (20) and method (100) are able to predict the COR in a non-destructive manner for a particular golf ball and impact speed. The system (20) and method (100) utilize a vibration sensor (24) attached to the face (34) of a golf club (30). The vibration sensor (24) is excited with an excitation device (26), and data is transmitted to an analyzer (22). A mathematical model of the golf club (30) is created allowing for the coefficient of restitution to be predicted without destroying the golf club (30).
Claims9
A method for predicting a coefficient of restitution (COR) of a golf club, the method comprising:
- attaching a vibration sensor to a face of the golf club;
- impacting the attached vibration sensor with an excitation device to generate vibrations in the face;
- transmitting a force of excitation from the excitation device and the vibrations measured by the vibration sensor to an analyzer to generate frequency domain data for the golf club;
- generating a graph of frequency versus magnitude of transfer accelerance from the frequency domain data;
- analyzing the phase of the graph of frequency to determine when the face of the golf club is traveling inward and outward for determining a contact point velocity;
- selecting a frequency band to minimize noise, the frequency band ranging from 500 Hertz to a first inflection point of the graph;
- calculating a transfer function from the frequency band of the graph;
- and
- inputting a golf ball model for a specific golf ball and an impact speed into the transfer function that contains an acceleration magnitude and direction of the face of the golf club in order to generate a predicted COR for the golf club at the impact speed with the specific golf ball, the golf ball model comprising a contact duration of the specific ball, a contact force of the specific ball, a COR of the specific ball and a mass of the specific ball.
A method for predicting a coefficient of restitution (COR) of a golf club head, the method comprising:
- attaching an accelerometer to a face of the golf club head;
- impacting the attached accelerometer with an impact device to generate vibrations in the face;
- transmitting a force of impact from the impact device and the vibrations measured by the accelerometer to an analyzer to generate frequency domain data for the golf club head;
- generating a graph of frequency versus magnitude of transfer accelerance from the frequency domain data;
- analyzing the phase of the graph of frequency to determine when the face of the golf club is traveling inward and outward for determining a contact point velocity;
- analyzing the graph of frequency to determine a first anti-resonance;
- selecting a frequency band to minimize noise, the frequency band ranging from 500 Hertz to a first inflection point of the graph;
- calculating a transfer function from the frequency band of the graph;
- and
- inputting a golf ball model for a specific golf ball and an impact speed into the transfer function that contains an acceleration magnitude and direction of the face of the golf club in order to generate a predicted COR for the golf club head at the impact speed with the specific golf ball, the golf ball model comprising a contact duration of the specific ball, a contact force of the specific ball, a COR of the specific ball and a mass of the specific ball.
Dependencies are inferred from the claim text.