US Patent 7371199 One-way clutched damper for automatic belt tensioner

A new asymmetrically damped tensioner is provided utilizing a one-way clutch connected to a tensioner arm through a frictional damper. The frictional damper is in frictional contact with the arm and the one-way clutch is coupled to the frictional damper for movement therewith. The tensioner arm is pivotable in a first direction to take up belt slack and a second direction. The clutch is pivotable in the first direction but not the second direction. Because the one-way clutch is operatively engaged with the arm through the frictional damper, the tensioner is able to respond to high belt tension once the frictional force between the arm and the damper is overcome.