Patent ID: 7621711

Claim:
A hydraulic control system for a mobile machine having a shovel retained on a boom that is pivoted by a boom cylinder, the shovel being pivoted by a shovel cylinder, and a transmitting member being operably connected to the shovel, the hydraulic control system comprising: a shovel control unit configured to control the shovel cylinder; a boom control unit configured to control the boom cylinder; and an orientation control device configured to receive a position of the shovel from the transmitting member and transmit hydraulic or electric signal indicative of the shovel position to the shovel control unit, the orientation control device comprising: a control lever having a variable basic position and being in operative connection with the transmitting member such that both a downward pivoting of the shovel and an upward pivoting of the shovel from a target angular position results in a positional change of the control lever; a spring assembly that connects the control lever with the transmitting member and a tensile spring assembly that connects the control lever with an actuation lever whereby a target position of the control lever may be adjusted by the actuation lever and the pivotal change of the shovel can be transferred to the control lever by the transmitting member; and a pilot control device configured to convert the positional change of the control lever during the pivotal change of the shovel into an electric or hydraulic control signal for at least one of keeping the shovel in the target angular position, returning the shovel to the target angular position, and resetting the control lever in a direction of a pre-set basic position of the control lever.