Tennis ball throwing machine

Abstract

A tennis ball throwing machine includes a support frame for carrying the machine, a pair of round pitching wheels, and a hopper mounted on the frame and above the pitching wheels. A ball chute connects the bottom of the hopper and a launch point that is proximate the point where the pitching wheels are closest together. The ball chute includes a plurality of guide rails that are spaced apart and open between them such that the guide rails are separated but are close enough together that they may support and carry a ball down the chute. The open rails allow for dirt and other debris to fall through the machine and away from the ball chute.

That which is claimed is: 
     
         1 . A tennis ball throwing machine for throwing balls of a selected substantially uniform compressible type comprising:
 a support frame for carrying a pair of pitching wheels and drive motors;   the pair of pitching wheels being round and with their axes of rotation being substantially parallel, rotatably mounted on the support frame wherein the wheels each comprise a ball engaging peripheral surface and those respective surfaces are adjacent one another and laterally spaced such that a ball is at least slightly compressed when passing between the surfaces;   the pair of drive motors mounted on the support frame and connected one each to the pitching wheels to cause those wheels to rotate in opposite directions at variable speeds;   a hopper mounted on the support frame and above the pitching wheels;   a ball chute positioned in a path from a bottom of the hopper and a launch point that is proximate the point where the peripheral surfaces of the pitching wheels are closest together, wherein the ball chute comprises a plurality of guide rails that are spaced apart and open between them, and the guide rails are separated at a distance apart to support and direct a ball that maybe carried by the rails, whereby debris is free to fall out of and away from the ball chute.   
     
     
         2 . A tennis ball throwing machine as described in  claim 1  wherein the hopper comprises a generally solid base but for a generally ball-sized aperture therein, and the ball chute is connected proximate to the hopper at and around the aperture, and
 wherein the hopper further comprises a rotating turntable mounted on the base of the hopper, and the turntable has a ball-sized opening therein with the opening intersecting the aperture with each revolution of the turntable on the base, whereby the delivery of balls to the chute is controlled by the speed of rotation of the turntable. 
 
     
     
         3 . A tennis ball throwing machine as described in  claim 2 , wherein the turntable comprises multiple openings that intersect with the aperture with each rotation of the turntable on the base. 
     
     
         4 . A tennis ball throwing machine as described in  claim 2 , wherein the base of the hopper further comprises a trigger latch proximate the side of the aperture where balls may be fed into the aperture, the trigger latch adapted to detect the presence or absence of a ball in the turntable opening aligning with the aperture during the rotation of the turntable on the base. 
     
     
         5 . A tennis ball throwing machine as described in  claim 2 , further comprising an electronic processor mounted on the support frame and connected to the drive motors and to the hopper turntable motor, the processor adapted to allow a user to control the speed and position of each of the motors. 
     
     
         6 . A tennis ball throwing machine as described in  claim 1 , wherein the ball chute defines a passageway for a tennis ball in the path from the hopper to the launch point, and further wherein a portion of the passageway is defined by one of the pitching wheels and the diameter of the passageway in this portion is slightly less than the diameter of a tennis ball. 
     
     
         7 . A tennis ball throwing machine as described in  claim 1 , wherein the axes of rotation of the pitching wheels are moveable respective to one another whereby the trajectory of a ball thrown by the machine may be changed. 
     
     
         8 . A tennis ball throwing machine as described in  claim 1 , wherein the guide rails comprise generally parallel, spaced apart, metal blades. 
     
     
         9 . A tennis ball throwing machine as described in  claim 1 , wherein the guide rails comprise generally parallel, spaced apart, metal wires.