A pulley consists of a wheel turning on a fixed axle, with a groove along the edges to guide a rope or cable. It is also known as a machine made with a rope, chain or belt wrapped around a grooved wheel. A pulley manufacturer modifies the direction of the force, making it easier to lift things. It is a system of ropes and wheels that achieve the purpose of making an object easier to lift. A pulley makes work easier because it changes the direction of motion to work with gravity.
Pulley actually saves effort when you have more than one pulley working together. Pulley can work either on one wheel, two or four wheel by cutting down the effort needed to lift something. By adding pulleys, it increases the mechanical advantage and it becomes very easy to life the same load. Pulley also acts like a lever.