Reciprocating rotary-linear transformation

Crank and rod mechanisms 

This mechanisms was important for the first steam engines. Today we find cranks and rods in internal combustion engines, as well as windsceen wiper mechanisms.

Crankshaft mechanism 

We can connect multiple rods to one shaft. The rods are connected to cranks, and the cranks are connected to the crankshaft. We use crankshaft for combustion motors that use pistons. We also use them for sewing machines.

Cam mechanisms

A cam is an irregulary shaped device that rotates on a shaft. When the cam rotates, it pushes a special bar called a follower. The follower can move other parts or it can turn a switch on and off. In some mechanisms, a spring pushes the follower back to its original position. We can find camshaftsin toys, automatic tools and combustion motors. There are often eccentric cams in sewing machines and other devices that transform rotary motion to linear motion.