Roller Chain

—A form of chain used in power transmi ion. It consists of a series of pairs of rollers, known as center blocks, similarly joined by side links. Each roller rotates loosely on a hollow core, which is turned to smaller diameter at either end to fit a perforated side piece joining the rollers into pairs. The side links are set over these side pieces and bolted in place through the cores. In operation, a block chain with generous slack is liable to meet the sprocket with a clapping that at high speed becomes a continuous rattle. The roller chain largely avoids this trouble. Furthermore, being obviously easier in operation, it economizes power. Some authorities estimate its efficiency in driving as high as ninety eight per cent. under favorable conditions.