ASA

There are two types of links alternating in the bush roller chain. The first type is inner links, having two inner plates held together by two sleeves or bushings where rotate two rollers. Internal links alternate with the next type, the outer links, consisting of two outer plates held with each other by pins passing through the bushings of the inner links. The “bushingless” roller chain is similar in operation though not in structure; instead of separate 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. It has the advantage of removing one part of assembly of the chain.

The roller chain design reduces friction compared to simpler designs, leading to higher efficiency and less wear. The initial power transmission chain varieties lacked rollers and bushings, with both inner and outer plates held by pins which directly contacted the sprocket teeth; nevertheless this configuration exhibited extremely rapid put on of both sprocket tooth, and the plates where they pivoted on the pins. This issue was partially solved by the development of bushed chains, with the pins holding the outer plates passing through bushings or sleeves connecting the internal plates. This distributed the wear over a greater area; however the tooth of the sprockets still wore quicker than is desired, 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 leading to excellent resistance to wear of both sprockets and chain as well. There is even very low friction, as long as the chain is usually sufficiently lubricated. Continuous, clean, lubrication of roller chains is of main importance for efficient procedure as well as correct tensioning