Belt tensioner construction

Abstract

A belt tensioning device for an endless drive belt for a vehicle accessories drive system. A sheet metal bracket is adapted to be mounted on an engine in a stationary position adjacent the drive belt and has a lever plate pivotally mounted thereon. An idler pulley is rotatably mounted on the lever plate and is movable into belt tensioning engagement by coil springs mounted on the bracket and engaged with the lever plate. A pair of pockets is formed in the bracket, each of which has an inclined surface which extends upwardly toward the lever plate. A camming block formed of a friction material is movably mounted in each pocket. Each block has an angled surface which is slidably engaged with the inclined surface of the pocket and has a planar coupling surface which frictionally engages the lever plate. The friction blocks provide a damping force on the lever plate when the lever plate attempts to move in the non-belt tensioning direction. Coil springs are mounted in the pockets and exert a biasing force against the camming blocks to move the blocks along the inclined surfaces of the pockets and into engagement with the lever plate. The springs maintain a predetermined coupling force between the blocks and lever plate throughout the life of the camming blocks and drive belt.

Dependencies are inferred from the claim text.