Baseball-pitching machine

摘要

A baseball-pitching machine wherein a baseball is delivered into the constricted space between, and thereby gripped frictionally by, to oppositely rotating wheels which throw the ball. A single DC shunt wound motor is used to drive the wheels in cooperation with one variable drive pulley and an assortment of guide pulleys. One wheel is driven at a constant speed by the motor while the speed of the second wheel is adjusted by means of a variable drive pulley. By thus changing the speed of one of the two oppositely rotating wheels, it is possible to impart a variety of spins to the thrown ball and thus simulate curve and slider balls thrown by a professional pitcher. The axis of the variable drive pulley is fixed and the position of the belt within the variable drive pulley is controlled indirectly by means of a belt tensioning pulley operated by a screw.