| 摘要 |
A ball throwing apparatus has two opposed drive wheels, one on each side of an open-ended barrel. The peripheries of both drive wheels extend into the barrel in opposing fashion, the wheels being slightly offset so that the second periphery frictionally engages the ball before the first periphery does. This directs the ball initially on a path divergent from the barrel axis. The drive wheels are rotated at dissimilar speeds and/or the diameters of the wheels are not the same so that the peripheral speeds of the two drive wheels are different. This imparts a spin to the ball and gives it a curved flight path. The barrel is rotatably mounted to allow the barrel to be rotated about its longitudinal axis to any angular position. The barrel mounting is attached to a tripod, and the mounting can be adjusted to alter the attitude of the barrel to change the trajectory of the ball.
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