US Patent 7971594 Pendulum-type wheel washer

A vehicle wheel washer comprising a pair of spaced-apart, mirror image, depending spray arms with spray heads mounted at the lower ends and directed inwardly toward the wheels of a vehicle which passes between the spray heads. The spray arms are mounted pendulum-type from an overhead pivotal support to move in unison between angular displacement positions thereby to follow the wheels of the vehicle being washed for a considerable linear distance to increase the effectiveness of the wheel cleaning operation. A bi-directional hydraulic actuator controls the positions of the pendulum arms in combination with gravitational force.