Patent ID: 7144344

Claim:
A tensioner for a traction drive to maintain a power transmitting member, e.g. a belt, under tension, comprising: a base part defining an axis; a pivot arm connected to the base part for swinging about a rotation axis and having a free end for rotatable arrangement of a roller which is supported on the power transmitting member; a spring member acting on the pivot arm for urging the roller against the power transmitting member; and a damping unit acted upon by an axial force of the torsion spring for damping an adjusting movement of the pivot arm, said damping unit including a slitted friction bushing which is subjected to the axial force only, said friction bushing disposed in concentric surrounding relationship to the rotation axis and constructed in the shape of a disk formed with a wedge ring having conical inner and outer surfaces for formfitting engagement in a circular ring shaped recess formed in a member selected from the group consisting of the base part and the pivot arm, wherein the recess has contact surfaces to complement the inner and outer surfaces of the friction bushing for formation of two conical contact zones.