An idler sprocket is a device used to maintain the strain in a chain or chain drive system. Often comprising only a sprocket mounted on a spring tensioned arm, the idler sprocket pulls against the chain in a continuous manner to keep the chain limited all the time. The size of the sprocket used in an idler sprocket assembly does not have any influence on the overall performance of the chain travel; however; a more substantial sprocket will often last longer because of the slower rate of the sprocket, which saves use on the sprocket’s bearings. Maintenance for the idler assembly is commonly only an occasional greasing of the sprocket’s bearings.

When driving a machine by chain, the strain of the chain must be held at a constant in order to avoid the chain approaching from the get sprockets. By installing an idler sprocket in the travel program, the chain is certainly kept taut without being over-tightened. Operating a chain in an over-restricted condition can lead to premature bearing and chain failure while an idler sprocket positioned in the machine is often a method to greatly expand the life of the chain, sprockets and the bearings on the machine’s sprocket shafts.

The ideal installation of the idler sprocket is on the opposite side of the chain between the drive sprocket and the driven sprocket. The application should place the idler sprocket in a position that has the sprocket pressing or pulling the chain towards itself as it loops the two major sprockets in a shape similar to the letter B. This design allows the pulleys to pull the chain hard without hindering the idler at all as the drive chain passes over the sprocket. If a condition occurs which needs the drive to exert surplus strain on the drive chain, the idler will flex against the chain, allowing it to expand while staying in touch with the travel sprockets.

While the vast majority of idler sprockets are manufactured of steel, many materials are accustomed to produce an idler sprocket. Many poly or composite sprockets have been used in combination with great success plus some wooden sprockets have also been applied to some machinery without concern. Many machines, so that they can reduce the put on on the drive chain, use an aluminium, cast iron or metal sprocket covered in a nylon material. The metallic hub enables the idler sprocket to stay very strong while the nylon covering is gentle on the chain links.