MECHANISMS THAT CONTROL MOTION

DIRECTION CONTROL:RATCHETS

A ratchet is a mechanisms that controls the direction of motion. It allows motion in one direction, but not in the other, as you can see the  picture.

Some ratchets are reversible, so they can turn and loc in one direction to another.

 

SPEED REDUCTION:BRAKES

Brakes use friction to reduce speed. They are activated by certain levers. The lever transmits forcé to an output receptor, which puts pressure on the Wheel. This produces friction, which slows down the Wheel.

There are various types of brake systems according to where the friction is produced:

Ø  Disc brakes: A disc is connected to an axle. Brake pads apply pressure to the disc.

Ø  Brand brakes: A drum is connected to an axle. A fexible band applies pressure to the outside of the drum. These brake were used in carriages and they depended on the sttrength of the driver.

Ø  Drum brakes: A drum is connected to the axle. A pair of brake shoes apply pressure to the inside of the drum.