| 摘要 |
PROBLEM TO BE SOLVED: To prevent a trainee from discomfort feeling by making noise by spring vibration not last for a long time during ball throwing of a throwing machine to throw a ball by elastic energy by tension of a spring. SOLUTION: A rotation shaft 24 is rotatably supported by a rack 4. A drive means 40 to rotate the rotation shaft 24 in one direction against tension of a spring 34 within a part of angle rangeαof the rotation shaft 24 is provided. This machine is constructed so that the rotation shaft 24 is rotate with in the other part of angle rangeβby tension of the spring 34 together with a throwing arm 26 in a direction same as the above to throw a ball 2 forward. Viewing in the visual line along the axis of the rotation shaft 24, a regulating body 51 is equipped to regulate moving of the rotation shaft 24 in the direction crossing the longitudinal direction by pressing the midway part 50 in the longitudinal direction of the spring 34 equipped within the interval of the rotation shat 24 in a part of angle rangeα.
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