滑轮

例句：

1. 1. The car's engine is connected to the gearbox through a set of gears, which are controlled by a crankshaft.
   汽车的发动机通过一系列齿轮与变速箱相连，这些齿轮由曲轴控制。
2. 2. A pulley system is used in this machine to lift heavy objects without using any power.
   这个机器使用滑轮系统来举起重物，而不需要任何动力。
3. 3. The engineer adjusted the position of the crankshaft to improve theefficiency of the machine.
   工程师调整曲轴的位置以提高机器的效率。