Roller chain or bush roller chain is the kind of chain drive mostly used for tranny of mechanical power on many kinds of domestic, industrial and agricultural machinery, including conveyors, wire- and tube-drawing machines, printing presses, vehicles, motorcycles, and bicycles. It consists of a series of short cylindrical rollers held with each other by part links. It is powered by a toothed wheel called a sprocket. It really is a simple, reliable, and efficient[1] means of power transmission.
Though Hans Renold is credited with inventing 
the roller chain in 1880, sketches by Auto Chain Leonardo da Vinci in the 16th century show a chain with a roller bearing.