The Roller chain reference article from the English Wikipedia on 24-Apr-2004
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Roller chain

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Roller chain is the most common type of chain used for transmission of mechanical power in industrial and agricultural machinery.

Each link in the chain is made up two inner sides, two outer sides, two pins, two sleeves, and two rollers. The use of rollers reduces friction, resulting in less wear on both the chain and the sprocket than is the case with simpler types.

Roller chain is ordinarily spliced using a master link, which has additional parts to allow it to be inserted or removed with simple tools. Half links are available, and are used to increase the length of the chain by a single roller.

Roller chain is used in low- to mid-speed drives. At higher speeds, v-belts are quieter and wear better.

Roller chain is made in several sizes, the most common being 10, 20, 40, 60, and 60H. Most roller chain is made from steel. Stainless steel is used in food processing machinery, and nylon and brass are occasionally seen.

Bicycle chain is a form of roller chain, but flexes from side to side more so that it can be used with a cluster sprocket and derailleur.