Abstract:
A wrist watch which instantaneously displays the velocity of the service ball in kilometers or miles for its manual or electronic display during competitions.

Description:
BACKGROUND OF THE INVENTION 
     It is important for the player and the spectator to know the speed of the serve ball. Radar installations are not within the reach of the majority of tennis clubs, and amateurs wish to know their performances. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention concerns a wristwatch which allows immediate reading of the speed. The watch of the present invention is independent of the system which calculates this speed, and is only a practical and elegant support. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of the watch of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     This is how the spectator should operate the watch of FIG.  1 . Each pressure on the push-button ( 1 ) allows to display alternatively the calculated distance in kilometers or in miles in display ( 2 ). The distance covered by the ball is shown as 18 m50 in display ( 3 ) and is selected thorough a side push-button ( 4 ) which allows to scroll the distances in one direction or the other. Then, the spectator presses push-button ( 5 ) a first time at the moment when the racket hits the ball and a second time when the ball touches the serve square. The watch, which includes a system of microprocessors and software, stores this interval in memory, and after a simple calculation, displays the speed in kilometers as shown by ( 6 ). The visualization in miles requires an additional division by 1,609. The results are rounded to the closest kilometer or mile number. For a time of one second the calculation is 18.5×1×3600=67 kmh, or 41 miles. In the case of an aborted serve, one push on the push-button ( 7 ) annuls the calculations. In any event, the display is erased automatically after ten seconds without manipulation. 
     This watch can be used in other games and sports with distances up to 100 meters and up to a time of one minute, in athletics, cycling, golf etc. The results during a competition can be displayed in a matter of seconds by a manual display panel or by electronic means with telecontrol.