Belt tensioner and method of making the same

摘要

A tensioner for a power transmission belt or the like that is adapted to be operated in an endless path and a method of making the same are provided, the tensioner comprising a support unit for being fixed relative to the belt, a belt engaging unit carried by the support unit and being movable relative thereto, a polymeric spring unit being operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt, and a coiled mechanical spring also being operatively associated with the support unit and the belt engaging unit for urging the belt engaging unit relative to the support unit and against the belt with a force to tension the belt whereby the polymeric spring unit and the mechanical spring combine to define the tensioning force for the belt while the polymeric spring unit additionally tends to dampen the movement of the belt engaging unit relative to the support unit, the mechanical spring being substantially completely embedded in the polymeric spring unit so that the mechanical spring is substantially completely engaged and surrounded by the polymeric spring unit.