Patent ID: 7200993

Claim:
An electro-hydraulic steering control system for directing fluid to steering actuators on a machine, comprising: a main valve in fluid communication with the steering actuators and configured to control fluid flow to the steering actuators; left and right primary steering valves in communication with the main valve and configured to provide fluid pressure to affect the main valve to control fluid flow to the steering actuators; left and right redundant steering valves in communication with the main valve and configured to provide fluid pressure to affect the main valve to control fluid flow to the steering actuators; a shuttle valve operably disposed between one of: the right primary and the right redundant steering valves; and the left primary and the left redundant steering valves, the shuttle valve being operable to selectively control fluid from the one of the right primary and the right redundant steering valves and the left primary and the left redundant steering valves to the main valve to control the main valve.