Patent ID: 7617906

Claim:
An apparatus for turning steerable wheels of a vehicle in response to turning of a steering wheel of the vehicle, the apparatus comprising: a first mechanism for connection to the steering wheel having a first member connected to a first pivot point of at least one of the steerable wheels, said first member being movable to turn the steerable wheels in response to turning of the steering wheel; a second mechanism having a hydraulic power steering gear and a second member spaced from the first member and connected to a second pivot point of the at least one of the steerable wheels, said steering gear being free of a rotary valve responsive to a steering input generated by turning of the steering wheel, said steering gear including a first chamber for holding hydraulic fluid and a second chamber for holding hydraulic fluid, an increase in fluid pressure in one chamber acting to move the second member to turn the steerable wheels of the vehicle in one direction and an increase in fluid pressure in the other chamber acting to move the second member to turn the steerable wheels in a direction opposite the one direction; and a variable flow mechanism for supplying a flow of hydraulic fluid to the first and second chambers of said hydraulic steering gear, that varies in dependence upon at least one sensed vehicle condition.