Patent ID: 8651225

Claim:
A control valve assembly for an electro-hydraulic steering system comprising: a first flow path having a fluid inlet, a fluid outlet, a first actuation outlet and a second actuation outlet, wherein the first flow path is adapted selectively to communicate fluid between the fluid inlet, the fluid outlet and the first and second actuation outlets via a first control valve; and an isolation valve system disposed in the first flow path, the isolation valve system being actuated between an open position, in which fluid can be selectively communicated between the fluid inlet and the first and second actuation outlets of the first flow path, and a closed position, in which fluid communication between the fluid inlet and the first and second actuation outlets is blocked, the isolation valve system including an isolation valve having a first end and a second end, the isolation valve being adapted for actuation to a closed position by fluid communicated to the first end from a second flow path in a parallel flow configuration with the first flow path, wherein the isolation valve system provides priority to the second flow path with fluid communicated from the second flow path.