This control effect can be got by designing the size of pokedwheel,using the self locking character of worm wheel and worm pole and connecting the pawl mechanism with overtravel ...

• 通过有效设计拨轮的尺寸，利用蜗轮蜗杆的自锁特性，将棘轮机构与行程开关联为一体，达到自动输球控制的目的。