There are two types of links alternating in the bush roller chain. The first type is internal links, having two inner plates held jointly by two sleeves or bushings where rotate two rollers. Internal links alternate with the next type, the external links, comprising two external plates held together by pins moving through the bushings of the internal links. The “bushingless” roller chain is similar in operation though not in structure; instead of separate bushings or sleeves holding the inner plates collectively, the plate has a tube stamped involved with it protruding from the hole which serves the same purpose. This has the advantage of removing one part of assembly of the chain.
The roller chain design reduces friction in comparison to simpler designs, leading to higher efficiency and less wear. The initial power transmission chain types lacked rollers and bushings, with both inner and outer plates kept by pins which directly contacted the sprocket teeth; however this configuration exhibited extremely rapid put on of both sprocket teeth, and the plates where they pivoted on the pins. This problem was partially solved by the development of Auto Chain bushed chains, with the pins keeping the outer plates moving through bushings or sleeves connecting the inner plates. This distributed the use over a greater area; however the tooth of the sprockets still wore more rapidly than is desirable, from the sliding friction against the bushings. The addition of rollers around the bushing sleeves of the chain and supplied rolling contact with one’s teeth of the sprockets leading to excellent resistance to wear of both sprockets and chain aswell. There is even suprisingly low friction, provided that the chain is usually sufficiently lubricated. Constant, clean, lubrication of roller chains is definitely of principal importance for efficient procedure as well as correct tensioning