US Patent 9650071 Bi-directional towed snowplow and method of plowing

A steering mechanism for steering at least two wheels in a parallel manner throughout their arcs of rotation by removing Ackerman and other steering geometries so that the wheels may remain parallel. The steering mechanism includes a central linkage for modifying the arcs of rotation of the wheels. The steering mechanism is controlled by an actuator system that also operates a restriction device to ensure safe operation. The steering mechanism and the actuator system may be included in vehicles such as a bi-directional towed snowplow.