US Patent 10203025 Belt tensioner with supplemental force element

Zed-type belt tensioners are described that include an arm having a first end rotatable about a first axis to move a second end of the arm into engagement with a belt, a tensioner component coupled to the first end of the arm, and a supplemental force element positioned between the arm and the tensioner component. The second end of the arm while tensioning a belt experiences a hub load applied by the belt and the supplemental force element is positioned at a point to apply a force that counteracts the hub load thereby reducing cocking of the arm. Also described herein are methods of counteracting the hub load using such belt tensioners and methods of assembly of such belt tensioners.