Anti-tilt belt tensioner and method for installing the same

Abstract

A belt tensioner for a motor vehicle engine comprises a pivot shaft and an eccentric pivoted structure mounted for pivoted movement on the pivot shaft. The belt tensioner has a rotatable pulley member mounted for rotation on the eccentric pivoted structure. A spring is constructed and arranged to bias the eccentric pivoted structure in a direction tending to force the rotatable pulley member into tensioning engagement with a belt trained about the pulley member. A mounting bolt is constructed and arranged to mount the belt tensioner on the motor vehicle engine, said pivot shaft being movable relative to said mounting bolt and towards said belt during a belt tensioner installation procedure. A linear guiding structure provides surfaces of interengagement between said belt tensioner and said motor vehicle engine to limit movement of the pivot shaft to linear movement toward the belt during the installation procedure. The present invention also relates to a method of installing a belt tensioner in which the pivot shaft moves in a substantially exactly linear fashion as the tensioner is moved into tensioning engagement with the belt. In a preferred embodiment, when the belt tensioner is moved into tensioning engagement with the belt, an external force is applied to the tensioner to balance any belt load forces tending to tilt the tensioner during installation. The present invention also discloses a tensioner that has contact portions that oppose the tilting force applied by the belt during installation, and a portion that extends beyond the contact portions to facilitate installation.