An idler sprocket is a gadget used to keep the strain in a chain or chain get system. Often consisting of nothing more than a sprocket installed on a spring tensioned arm, the idler sprocket pulls against 
the chain in a continuous manner to keep carefully the chain restricted at all times. How big is the sprocket found in an idler sprocket assembly does not have any effect on the performance of the chain travel; however; a larger 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 no more than an occasional greasing of the sprocket’s bearings.
When driving a machine simply by chain, the tension of the chain should be kept at a continuous to avoid the chain coming from the get sprockets. By setting up an idler sprocket in the drive system, the chain is usually kept taut while not being over-tightened. Operating a chain in an over-restricted condition can result in premature bearing and chain failing while an idler sprocket placed in the machine is often a way to greatly lengthen the life of the chain, sprockets and the bearings on the machine’s sprocket shafts.
The ideal installing the idler sprocket is on the opposite side of the chain between your travel 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 main sprockets in a form similar to the letter B. This design will allow the pulleys to draw the chain hard without hindering the idler in any way as the drive chain passes over the sprocket. If a condition occurs which needs the drive to exert surplus pressure on the drive chain, the idler will flex against the chain, and can expand while remaining in touch with the drive sprockets.
While the vast majority of idler sprockets are manufactured of steel, many materials are used to produce an idler sprocket. Many poly or composite sprockets have been used in combination with great achievement plus some wooden sprockets have also been used on some machinery without issue. Many machines, so that they can reduce the use on the drive chain, use an lightweight aluminum, cast iron or steel sprocket coated in a nylon materials. The metallic hub enables the idler sprocket to remain very strong as the nylon covering is soft on the chain links.