Type U Drive Positioner
The Murray Type U drive positioner is a fixed idler bracket which provides support for a chain or belt. Like all Murray tensioners and positioners, it is constructed of structural steel. Available in a wide variety of sizes. Type U positioners can be mounted on any flat, vertical surface.
- Tensioning that is too tight causes excessive wear on chain, belt and bearings.
- Tensioning that is too loose allows belt slippage or chain vibration, causing loss of horsepower or wear.
- Idlers should be located on the slack side of the drive chain or belt.
- The use of idlers on the back of V-belts causes reverse bend, and can reduce belt life. However, when inside idlers are used, the arc of contact is reduced and allowance must be made for horsepower loss.
- Chain idlers should be run on the outside of the chain.
- Idler sprockets should have at least three teeth engaged with the chain.
- Idlers, when used on the outside of the drive, should be located approximately 1/3 of the center distance from the small pulley or sprocket.
- Idlers, when used on the inside of the drive, should be located approximately 1/3 of the center distance from the large pulley or sprocket.