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System and apparatus for program controlled delivery of game balls

Image Number 7 for United States Patent #4269163.

An ejector for a sequence of game balls has variable device for setting a different trajectory for each ball and for varying the time interval between each ball delivery. A controller includes an input device used by the tennis player or instructor to enter the court and ball data for each of a sequence of balls; a converter for changing the court and ball data to corresponding trajectory data used in setting the ball ejector; and a digital memory for storing the data for each ball. The controller is switched to a programming mode for setting up the court and ball data for the sequence of balls to be delivered and to an operating mode in which the balls are delivered in accordance with the set program.

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