Patent ID: 7419447

Claim:
A belt tensioner for a belt drive system having a belt tensioner, a first belt tensioner pulley, a crankshaft pulley, an accessory pulley, and a power transmission belt trained about said first belt tensioner pulley, said crankshaft pulley, and said accessory pulley, said belt tensioner comprising: an attachment point adapted to be affixed to a stationary point relative to a cylinder block of an engine, a track, a first crier mounted in sliding relation with said track with two degrees of freedom of movement along said track, said first belt tensioner pulley rotatably mounted upon said first carrier for linear movement along said track to engage said power transmission belt, a resilient member biasing said first carrier in longitudinal relation to said track, a second carrier mounted in sliding relation with said track a first damping mechanism that modifies the biasing of said resilient member based upon movement of said first carrier in relation to said track, said first damping mechanism including a first shoe placed in a first asymmetrical damping relation to said first carrier and said track, and including a first friction bearing surface in mating relationship with a friction bearing surface of said track with two degrees of freedom of movement along said track, said second carrier being biased in longitudinal relation to said track, and a second belt tensioner pulley rotatably mounted upon said second carrier for linear movement along said track to engage said power transmission belt.