| 摘要 |
<p>A device (10) for practicing playing a ball game, such as tennis, comprises an arm (29) one end portion of which carries a ball (31), such that the ball (31) is rotatable retained relative to the arm (29), and a remote end portion of which is secured to a face of a toothed pulley wheel (25) which is rotatable mounted on a swingable link means (16, 17, 18) pivotally mounted on a shaft (13). A second, larger, toothed pulley wheel (14) is rotatably mounted on the shaft (13), there being resilient means (23) for restraining such rotation. The toothed pulley wheels (14, 25) are engaged by a toothed endless belt (26). The arrangement is such that, when the arm (29) pivots relative to the axis of rotation of the smaller toothed pulley wheel (25) as a result of the ball (31) being hit in a direction (A), the smaller pulley wheel (25) moves in the same direction and the resultant trajectory of the ball (31) is closer to a typical trajectory of a tennis ball passing over a net in a game over a net in a game of tennis than would be the situation with tennis practice device known hitherto.</p> |
