4.1. ROTARY-LINEAR TRANSFORMATION

Wheel

With each rotation, a wheel moves forward a distance that is equal to its circumference(2 times PI times R). As a result, we need less force to move vehicles with larger wheels and they move more quickly.

Rack and pinion mechanism

A rack and pinion mechanism has two parts. The rack is a bar with many teeth and the pinion is a gear with teeth that interlock with the rack.

Nut and bolt mechanism

A nut and bolt mechanism transforms rotary motion into linear motion. It has two parts: a bolt of shaft with a spiral groove and a nut that turns around it.

USES: We use it to hold things together. We can also fin them in scissor jacks for lifting cars, water tap mechanisms and screw-top bottles.

Winch and crank mechanism

A winch is a cilinder that rotates around an horizontal axis. We attach a rope to the winch and to a load. Then we turn the crank to rotate the winch. The rope rolls up around the winch and lifts the load.

F x d = R x r

We use winch and crank mechanism to lift or pull heavy loads.