Tensioner with expanding spring for radial frictional asymmetric damping

A tensioner consisting essentially of:

• a support member comprising a shaft defining a first axis;
• an arm comprising an arm arbor mounted on said shaft for rotatable movement of the arm about the first axis, the arm arbor having a fixed diameter and defining a cavity and having a slot open into the cavity;
• a single bushing having a protrusion dimensioned to extend through the slot of arm arbor and into the cavity of the arm arbor, wherein the bushing is between the support member and the arm with the protrusion extending through the slot and into the cavity of the arm arbor;
• a spring received in the cavity of the arm arbor with a coil thereof juxtaposed to the protrusion of the bushing and operatively coupled to the arm,
• a pulley rotatably mounted to the arm;
• and
• a cap enclosing the spring within the tensioner;
• wherein the spring radially urges the arm to rotate about the first axis into tensioning engagement with a power transmitting element, and wherein the protrusion of the bushing is positioned relative to the spring such that the coil of the spring radially expands to contact and urge the protrusion of the bushing as the arm is rotated in a direction opposite the direction of tensioning engagement, and wherein radial expansion of the spring urges the bushing radially outward relative to the arm arbor into frictional engagement with the support member to provide frictional damping.