US Patent 7258194 Vehicle steering system having a rear steering control mechanism

A vehicle steering system includes a steering input device, a front steering subsystem, a rear steering subsystem, a first force transmission route, a steering control mechanism, a second force transmission route, and a third force transmission route. The front steering subsystem is coupled to front motive members to steer the front motive members based upon movement of a front steering subsystem input shaft. The rear steering subsystem is coupled to rear motive members to steer the rear motive members based upon movement of a rear steering subsystem input shaft. The first force transmission route extends from the steering input device to the front steering subsystem input shaft, wherein force is transmitted from the input device to the front steering subsystem input shaft to steer the front motive members. The steering control mechanism has a movable input member and a movable output member. The movable input member is movable through a first distance without transmitting force to the output member and is movable through a second distance in which force is transmitted to the output member to move the output member. The second force transmission route extends from the steering input device to the input member, wherein force is transmitted from the input device to the input member to move the input member. The third force transmission route extends from the output member to the rear steering subsystem input shaft to move the rear steering subsystem input shaft and to steer the rear motive members.