speed pulley

• 变速皮带轮

speed pulley的用法和样例：

例句

1. The belt started wrapping up on the tractor pulley.
   皮带开始绕在拖拉机的皮带轮上。
2. Attach the pulley which is held by hand with screws.
   用螺丝安装皮带轮的手持部分。
3. The lifting device is a system of rope and pulley.
   这种起重装置是由缆索和滑轮组成的。
4. A single fixed pulley does not help to save effort.
   一个单独的固定的滑轮不能帮助节省气力。