Patent ID: 8689549

Claim:
Hydraulic control circuit for the overcontrol of a hydraulic system which controls a hydraulic motor ( 5 ) for driving a slewing gear of a crane superstructure, the hydraulic control circuit comprising: pressure lines ( 3 . 9 , 3 . 10 ) for the hydraulic motor ( 5 ), wherein the pressure lines ( 3 . 9 , 3 . 10 ) are connected by means of a supply piston ( 3 . 2 ) to a hydraulic pump ( 2 ) or a tank ( 1 ), and the pressure lines ( 3 . 9 , 3 . 10 ) are each operatively associated with pilot valves ( 3 . 4 , 3 . 3 ), shuttle valves ( 3 . 8 , 3 . 7 ), and separately activatable directional control valves ( 3 . 6 , 3 . 5 ), wherein a fluid flow to the tank is at least partially controlled by the separately activatable directional control valves ( 3 . 6 , 3 . 5 ), wherein the shuttle valves ( 3 . 7 , 3 . 8 ) are connected by means of first control lines ( 3 . 11 , 3 . 12 ) to an activatable proportional pilot valve ( 6 ) and wherein the shuttle valves ( 3 . 7 , 3 . 8 ) are connected by means of second control lines ( 3 . 15 , 3 . 16 ) to pilot valves ( 3 . 3 , 3 . 4 ), such that the separately activatable directional control valves ( 3 . 5 , 3 . 6 ) can be activated thereby by means of pressure which is built up by the proportional pilot valve ( 6 ), and separately activated thereby by means of pressure which is built up by the pilot valves ( 3 . 3 , 3 . 4 ).