A loop of flexible material used to link two or more rotating shafts mechanically, most often parallel can be called as belts. Belts may be used as a source of motion, to transmit power efficiently or to track relative movement. Belts are divided into 3 main categories.

• Flat belts: They were the simple system of the power transmission. Flat belts were widely used in the 19th and early 20th centuries in line shafting to transmit power in factories. Although they were frequently used in farming, mining, and logging applications in those times; today it is not used as much as they were. The disadvantage of flat belt is when they forced to be under high loads, they can be slipped off the shafts.

• V-belts: They act as a transmitting belts. V belts transmit power that comes from engine to the parts like alternator and hydraulic steering pump. V belts solved the slippage and alignment problem of flat belts. V belts are the main belts in power transmission. They provide the best combination of traction, speed of movement, load of the bearings, and long service life.

• Timing Belts: They provide the positive and synchronized power transmission in car engines. Most important aim of timing belt is to ensure that the camshaft, injection pump, balancing shaft and other auxiliary components work in harmony. These belts have teeth that fit into a matching toothed pulley.