There are actually two types of links alternating in the bush roller chain. The 1st type is inner links, having two inner plates held jointly by two sleeves or bushings upon which rotate two rollers. Inner links alternate with the second type, the outer links, comprising two external 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 separate bushings or sleeves keeping the inner plates with each other, the plate includes a tube stamped involved with it protruding from the hole which serves the same purpose. This has the benefit 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 the inner and external plates held by pins which straight contacted the sprocket tooth; however this configuration exhibited incredibly rapid put on of both the sprocket the teeth, and the plates where they pivoted on the pins. This problem was partially solved by the advancement of bushed chains, with the pins keeping the outer plates passing through bushings or sleeves linking the inner plates. This distributed the use over a greater area; however the teeth of the sprockets still wore quicker than is desirable, from the sliding friction against the bushings. The addition of rollers encircling the bushing sleeves of the chain and offered rolling contact with the teeth of the sprockets leading to excellent resistance to use of both sprockets and chain as well. There is 
even suprisingly low friction, so long as the chain is definitely sufficiently lubricated. Continuous, clean, lubrication of roller chains is certainly of main importance for Leaf Chain efficient procedure as well as correct tensioning.