ratchet

棘轮；棘齿英释中释na machine part consisting of a wheel or bar with teeth on it, which allows movement in only one direction

安装棘轮于；松脱中释v

1 ratchet wheel,n. [机]棘轮

2 ratchet effect,齿轮效应

3 ratchet up,逐渐升高；略微调高

1 The chair has a ratchet below it to adjust the height..这把椅子下面有一个棘轮来调整高度。