| 摘要 |
<P>PROBLEM TO BE SOLVED: To precisely pitch a ball, to reduce the weight and sizes of a spring, and to improve the life of a ball pitching arm when rotating the ball pitching arm at high speed by the biasing force of the spring so as to pitch the ball. Ž<P>SOLUTION: The ball pitching arm projects outward from the side of a shaft 8 extending to the right and left, and can be rotated at high speed by the biasing force of the spring 22 in a predetermined rotation range α in rotation in one direction A around the shaft 8. A ball receiving part 15, where the ball 2 can be placed just before the predetermined rotation range α, is generated at the projecting end of the ball pitching arm 10. By the high-speed rotation of the ball pitching arm 10, the ball 2 placed on the ball receiving part 15 is pitched forward. The ball receiving part 15 is formed of reinforced resin 30 so as to have a hollow structure. The ball pitching arm 10 positioned just before the predetermined rotation range α is V-shaped in the cross section of the ball receiving part 15 in a cross-sectional view (Fig.5) viewed by the eyes along the longitudinal direction thereof. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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