This apparatus is designed to study the working and characteristics of slider crank mechanism. Connecting rod and crankshaft are used in engines to convert linear motion of piston into rotational motion of crankshaft etc.
The unit consists of two arms connected to each other by a sliding link. This arm is termed as crank and the other arm is called slider arm or connecting rod. The scale on slider arm is used to measure the linear displacement while the scale on the circular disc shows the angular displacement.