sliding contact gears

例句：

1. 1. The new elevator has a sliding contact gear system that makes it easy to move up and down.
   新电梯有一个滑动接触齿轮系统，使得上下移动变得容易。
2. 2.The machine's design features a sliding contact gear for smooth operation.
   机器的设计特点包括一个滑动接触齿轮，以实现平滑操作。
3. 3. In the old days, people used to use sliding contact gears for power transmission.
   在旧时代，人们使用滑动接触齿轮进行动力传输。