Patent ID: 8002657

Claim:
A tensioner to tension a flexible drive, comprising: a mounting plate; a pivot shaft extending from the mounting plate; a pivot bushing non-rotatably mounted about the pivot shaft for slidable axial movement, said pivot bushing having an outer frustoconical surface; a tensioner arm having a pivot surface complementary to and engaging the outer frustoconical surface of the bushing to allow the tensioner arm to pivot about a first axis; a rotatable member mounted on said tensioner arm rotatable about a second axis, said second axis spaced from and parallel to said first axis; a spring acting between the mounting plate and the tensioner arm to bias the tensioner arm to urge the rotatable member into tensioning engagement with said flexible drive, wherein said spring has an arcuate shape corresponding to an arcuate path followed by the tensioner arm as the tensioner arm pivots about the first axis; a spring retainer fixed to the mounting plate, the spring retainer having an inner surface that engages the spring along substantially the entire length of the spring to restrain the spring from bulging outwardly from the arcuate shape when the spring undergoes compressive forces; and a wear take up mechanism biasing the bushing into engagement with the tensioning arm to compensate for wear between the pivot bushing and pivot surface.