A sprocket[1] or sprocket-wheel[2] is a profiled wheel with the teeth, or cogs,[3][4] 
that mesh with a chain, track or other perforated or indented materials.[5][6] The name ‘sprocket’ applies generally to any wheel upon which radial projections engage a chain moving over it. It is distinguished from a equipment in that sprockets are never meshed together straight, and differs from a pulley for the reason that sprockets have tooth and pulleys are even.
Sprockets are found in bicycles, motorcycles, cars, tracked automobiles, and other machinery either to transmit rotary movement between two shafts where gears are unsuitable or to impart linear motion to a track, tape etc. Maybe the most typical form of chain sprocket sprocket may be found in the bicycle, in which the pedal shaft bears a huge sprocket-wheel, which drives a chain, which, in turn, drives a small 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 varied designs, no more than efficiency getting claimed for every by the originator. Sprockets typically don’t have a flange. Some sprockets used in mixture with timing belts possess flanges to keep the timing belt centered. Sprockets and chains are also utilized for power transmission in one shaft to some other where slippage isn’t admissible, sprocket chains getting used rather than belts or ropes and sprocket-wheels instead of pulleys. They may be run at high speed and some kinds of chain are so built as to be noiseless also at high speed.