There are two types of links alternating in the bush roller chain. The initial type is internal links, having two inner plates held collectively by two sleeves or bushings where rotate two rollers. Internal links alternate with the second type, the external links, consisting of two outer plates held jointly by pins passing through the bushings of the internal links. The “bushingless” roller chain is comparable in procedure though not in construction; instead of Drive Chain individual bushings or sleeves keeping the inner plates collectively, the plate has a tube stamped into it protruding from the hole which serves the same purpose. This has the benefit of removing one step in assembly of the chain.
The roller chain design reduces friction compared to simpler designs, resulting in higher efficiency and less wear. The original power transmission chain types lacked rollers and bushings, with both inner and outer plates held by pins which directly contacted the sprocket the teeth; nevertheless this configuration exhibited extremely rapid wear of both sprocket teeth, and the plates where they pivoted on the pins. This problem was partially solved by the advancement of bushed chains, with the pins holding the outer plates moving through bushings or sleeves connecting the inner plates. This distributed the wear over a greater area; however the tooth of the sprockets still wore quicker than is attractive, from the sliding friction against the bushings. The addition of rollers encircling the bushing sleeves of the chain and supplied rolling contact with one’s teeth of the sprockets resulting in excellent resistance to wear of both sprockets and chain as well. There is even suprisingly low friction, so long as the chain can be sufficiently lubricated. Constant, clean, lubrication of roller chains is usually of principal importance for efficient operation and also correct tensioning.