ratchet wheel pawl pin

例句：

1. 1. The car's engine is a ratchet wheel that engages with the gears to start the engine.
   汽车的发动机是一个棘轮，它与齿轮啮合以启动发动机。
2. 2.The lock has a pawl that prevents it from being opened accidentally.
   这把锁有一个棘爪，防止它不小心被打开。
3. 3. The pin was used to secure the bolt in place.
   这个销钉用来固定螺栓到位。