Patent ID: 7207910

Claim:
A decoupler, comprising: a hub structure capable of being mounted on a shaft; a pulley mounted on said hub structure and capable of relative rotational movement with respect to said hub structure; a coil spring extending between said pulley and said hub structure resiliently coupling said pulley with said hub structure, said coil spring transmitting driven rotational movements of said pulley to said hub structure; and an inner spring engaging structure rotatably mounted on said hub structure and rotationally fixed with respect to said pulley, said inner spring engaging structure engaging volutes of said coil spring as a result of radial contraction of said coil spring, wherein said hub structure has a radial portion frictionally engaging said pulley, whereby radial contraction and expansion of said spring urges said radial portion out of and into frictional engagement with said pulley, respectively, generating a proportional damping force moderating velocity differences between said hub structure and said pulley.