Mechanisms that control motion

⇨ DIRECTION CONTROL : RATCHETS

A ratchet is a mechanism that controls the direction of motion. Only allows motion in one direction.
Some ratchets are reversible, they can turn to both directions. We find them in watches, cable-tensors and elevator brake systems.


⇨ SPEED REDUCTION : BRAKES

Brakes use friction to reduce speed, and they are activated by levers. The levers transmit force to an output receptor, which puts pressure on the wheel. This produces friction, that slows down the wheel.
There are 3 types:

♦ Disc brakes: It is connected to an axle. The disc has pressure thaks to the brake pads.
♦ Band brakes: A drum is connceted by an axle. A fexible band puts pressure on the outside of the drum. We use them in carriages and they depended on the strength of the driver.
♦ Drum brakes: A pair of brake shoes apply pressure to the inside of the drum.

DRUM BAKE

BAND BRAKE