Racket String Tensioning System

Abstract

The present invention is directed at string tensioning system for use in racket stringing machines. The system produces accurate and consistent string tensions, requires minimum maintenance, works with a weak current source, such as a battery, and provides quick adjustment options, all achieved in a low-cost manner. The system may comprise a crank, a control module, a force sensor, and a brake mechanism. The system may further comprise an electric tensioning mechanism. The present invention is further directed at a string tensioning method. The method may comprise: fixing the first end of a racket string to a string holder of the string tensioning system, manually tensioning the racket string using a crank, and, in some embodiments, automatic tensioning of the racket string by an electric tensioning mechanism.

I claim: 
     
         1 . A string tensioning system for use with racket stringing machines, the system comprising:
 a crank;   a force sensor coupled to the control module and configured to produce a tension signal based on a tension of a racket string;   a control module configured to produce a brake signal when the tension of the racket string reaches an intermediate tension; and   a brake mechanism coupled to the control module and configured to stop the crank from rotating upon receiving the brake signal.   
     
     
         2 . The string tensioning system of  claim 1 , further comprising an electric tensioner. 
     
     
         3 . The string tensioning system of  claim 2 , wherein the electric tensioner is configured to tension the racket string from the intermediate tension to a final tension. 
     
     
         4 . The string tensioning system of  claim 3 , wherein the electric tensioner tensions the racket string when the crank cannot rotate. 
     
     
         5 . The string tensioning system of  claim 3 , wherein the electric tensioner automatically tensions the racket string once the tension of the racket string reaches the intermediate tension. 
     
     
         6 . The string tensioning system of  claim 1 , further comprising a tension transfer bar. 
     
     
         7 . The string tensioning system of  claim 6 , where the force sensor senses a force of the tension transfer bar. 
     
     
         8 . The string tensioning system of  claim 1 , further comprising an input module coupled to the control module and configured to receive user inputs, the user inputs including at least the intermediate tension of the racket string and a final tension of the racket string. 
     
     
         9 . The string tensioning system of  claim 8 , wherein the intermediate tension is within 10% of the to the final tension. 
     
     
         10 . The string tensioning system of  claim 2 , wherein the system is operable without a connection to a strong current source. 
     
     
         12 . The string tensioning system of  claim 2 , wherein the electric tensioner is one of an electric motor and an actuator. 
     
     
         13 . The string tensioning system of  claim 2 , wherein the electric tensioner provides a constant pull feature. 
     
     
         14 . A method of tensioning a racket string, the method comprising:
 providing a string tensioning system, the system comprising:
 a crank; 
 a force sensor coupled to the control module and configured to produce a tension signal based on a tension of a racket string; 
 a control module configured to produce a brake signal when the tension of the racket string reaches an intermediate tension; 
 a brake mechanism coupled to the control module and configured to stop the crank from rotating upon receiving the brake signal; 
   fixing a first end of the racket string to a string holder of the string tensioning system, a second end of the racket string fixed to a racket;   manually tensioning the racket string using the crank until the tension of the racket string is equal to the intermediate tension, causing the brake mechanism to stop the crank from rotating.   
     
     
         15 . The method of  claim 14 , wherein the string tensioning system further comprises an electric tensioner configured to tension the racket string from the intermediate tension to a final tension. 
     
     
         16 . The method of  claim 15 , further comprising automatic tensioning of the racket string by the electric tensioner until the tension of the racket string is equal to a final tension. 
     
     
         17 . The method of  claim 16 , wherein the automatic tensioning is performed at least twice. 
     
     
         18 . The method of  claim 16 , wherein the string tensioning system is operable without a connection to a strong current source. 
     
     
         19 . The method of  claim 16 , wherein the electric tensioner is one of an electric motor and an actuator. 
     
     
         20 . The method of  claim 15 , wherein the string tensioning system further comprises an input module coupled to the control module and configured to receive user inputs, the user inputs including at least the intermediate tension of the racket string and the final tension of the racket string.