rocking handle

• 摇柄

rocking handle的用法和样例：

例句

1. You have to wind a handle at the side of your telephone.
   你得转动电话机旁的摇柄。
2. The source is placed to the left, and the observer is directly in front of the handle that turns the screw.
   光源放在左方，观察者就在转动螺旋的摇柄之正前方。