centring spring

例句：

1. 1.The clock's mechanism is made up of a central spring and a gear train.
   这个钟的机构由一个中心弹簧和齿轮传动系统组成。
2. 2. The new model car has a more powerful central spring than its predecessor.
   新款汽车比前一代拥有更强大的中心弹簧。
3. 3. The spring in the mattress is designed to distribute weight evenly and prevent sinking.
   床垫中的弹簧设计用来均匀分布重量，防止下沉。