Ratchet (device)

A catch is a mechanical device which prevents the reverse rotation of a ratchet wheel. As shown in the schematic diagram to the right engages the locking pawl in a ratchet wheel 2 to one asymmetrical tooth flanks. The pawl is mounted rotatably and is pressed by the force of gravity, a spring or other mechanism in the ratchet wheel. The special shape of the teeth allows a smooth forward rotation of the ratchet wheel, but prevents the reverse rotation.

The entire mechanism of ratchet, ratchet and locking spring called ratchet.

Applications

Pawls are used wherever an uncontrolled reverse rotation to be prevented. Examples include winches, ratchet lashing straps, door locks in automobiles, bicycle rear hub with freewheel, scraper floor drive, handcuffs and spring plants in watches.