A sprocket[1] or sprocket-wheel[2] is a profiled wheel with 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 where radial projections engage a chain moving over it. It chain sprocket really is distinguished from a equipment in that sprockets should never be 
meshed together straight, and differs from a pulley in that sprockets have tooth and pulleys are clean.
Sprockets are found in bicycles, motorcycles, vehicles, tracked automobiles, and other machinery either to transmit rotary movement between two shafts where gears are unsuitable or to impart linear movement to a track, tape etc. Perhaps the most typical form of sprocket could be found in the bicycle, where the pedal shaft bears a large 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 system, a practice mainly copied from bicycles.
Sprockets are of various designs, no more than efficiency becoming claimed for every by the originator. Sprockets typically don’t have a flange. Some sprockets used in combination with timing belts possess flanges to keep carefully the timing belt centered. Sprockets and chains are also utilized for power transmission from one shaft to another where slippage isn’t admissible, sprocket chains getting used instead of belts or ropes and sprocket-wheels instead of pulleys. They can be run at high speed plus some forms of chain are so constructed as to be noiseless actually at high speed.