Ratchet wrenches

Ratchet-reversing mechanism

— the presence in the key of a ratchet-reversible, or, as it is also called, a ratchet mechanism. This feature is found mainly among open-end spanners (see the relevant paragraph), and the “ratchet” is installed in the cap; however, there are other types of wrenches with similar equipment (including even open-end wrenches).

The mechanism itself can also have a different device, depending on the type of key. However, the principle of operation is the same everywhere: when turning in one direction, the key engages the fastener and rotates it, when turning in the other direction, it turns idle, so that the fastener remains motionless. So instead of having to rotate the tool a full 360° or constantly rearrange it, all you have to do is place the wrench on the fastener and rock it back and forth. This is especially convenient when working in cramped conditions, where the angle of rotation of the key is very small and without a “ratchet” it would have to be rearranged very often. Note that the direction switch in such devices may be absent: the mechanism works only in one direction, and the direction of rotation is changed by turning the key to the other side.