A sprocket[1] or sprocket-wheel[2] is a profiled wheel with the teeth, or cogs,[3][4] that mesh with a chain, monitor or other perforated or indented materials.[5][6] The name ‘sprocket’ applies generally to any wheel upon which radial projections engage a chain passing over it. It really is distinguished from a gear in that sprockets are never meshed together directly, and differs from a pulley in that sprockets have the teeth and pulleys are smooth.
Sprockets are found in bicycles, motorcycles, vehicles, tracked automobiles, and other machinery either to transmit rotary motion between two shafts where gears are unsuitable or even to impart linear motion to a track, tape etc. Perhaps the most sprockets common form of sprocket may be within the bicycle, where the pedal shaft bears a big sprocket-wheel, which drives a chain, which, in 
turn, drives a little sprocket on the axle of the trunk wheel. Early automobiles had been also largely driven by sprocket and chain mechanism, a practice largely copied from bicycles.
Sprockets are of various designs, no more than efficiency getting claimed for every by its originator. Sprockets typically do not have a flange. Some sprockets used with timing belts have flanges to keep the timing belt centered. Sprockets and chains are also utilized for power transmission in one shaft to some other where slippage is not admissible, sprocket chains getting used rather than belts or ropes and sprocket-wheels rather than pulleys. They can be run at high speed plus some types of chain are so built concerning be noiseless even at high speed.