Patent ID: 8322375

Claim:
A control device for the control of a hydraulic consumer comprising a directional valve ( 1 ; 54 ; 90 ) which has a control pressure chamber ( 32 ) and a control slider ( 26 ) which is adjustable against the force of a spring ( 35 ) by building up a control pressure in the control pressure chamber ( 32 ) and comprising a pilot control valve ( 40 ; 60 ) for the control of the inflow and outflow of control fluid into and out of the control pressure chamber ( 32 ), wherein a relief device ( 46 , 48 , 50 ; 68 a , 76 ; 86 ) is present by which the control fluid can be displaced from the control pressure chamber ( 32 ) while bypassing the pilot control valve ( 40 ; 60 ) in a condition when the pilot control valve ( 40 ; 60 ) is blocked, the relief device includes a relief line ( 48 ) communicating with a fluid tank, a pressure relief valve ( 50 ) situated therein and a check valve ( 46 ) via which control fluid can be displaced from the control pressure chamber ( 32 ) into the relief line ( 48 ), and the pressure in the pressure relief valve ( 50 ) is restricted to a value which is as high or higher than the maximum control pressure in the pilot control valve ( 40 ; 60 ), such that upon occurrence of the condition when the pilot control valve ( 40 ; 60 ) is blocked against further displacement of fluid from the control pressure chamber ( 32 ), the control slider ( 26 ) is guided back into a centered position despite blocking of the control valve ( 40 ; 60 ).