| 摘要 |
An improved apparatus for propelling balls such as baseballs and softballs with accurate and predetermined spins, speeds and placements which includes a pair of opposed spinning wheels, a guide to insert the ball to be thrown between the wheels and a motor which by means of a belt and pulleys, drives the two wheels at least at two predetermined ratios or speeds to impart the proper motion to the ball. The wheels are mounted so that the distance therebetween can be adjusted for balls of different diameters. A base is also included which optionally may include pivot means so that the plane of rotation of the spinning wheels can be rotated about the path of the ball to change the direction of the spin on the thrown ball and an automatic feed mechanism.
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