Patent ID: 8651223

Claim:
A synchronizing system for hydraulic four wheel steering comprising: a power steering valve operably connected to a steering wheel that may be turned to move the power steering valve between a full left turn position and a full right turn position; a double acting front steering cylinder and a double acting rear steering cylinder, each of the front and the rear steering cylinders connected by hydraulic lines to the power steering valve and moveable between a retracted position and an extended position in response to the position of the power steering valve; and a synchronizing valve assembly connected by hydraulic lines between the front and the rear steering cylinders, the synchronizing valve assembly including a first directional relief valve that opens in response to insufficient hydraulic fluid between the front and rear steering cylinders to dump hydraulic fluid into the hydraulic lines between the front and rear steering cylinders to synchronize the front and the rear steering cylinders in the full left turn position, and a second directional relief valve that opens in response to excess hydraulic fluid between the front and rear steering cylinders to dump hydraulic fluid into a reservoir to synchronize the front and the rear steering cylinders in the full right turn position.