Patent ID: 7849687

Claim:
Electrohydraulic adjusting device (E) for a solar panel carrier (T) which, at least for tracking the position of the sun, is rotatable and tiltable at a sub-structure ( 1 , U) by means of double-actuated hydrostatic rotation and tilt motors (M, M′) and selectively is tiltable such that the carrier (T) tends to automatically reach a protected position (S) without actuation by the hydrostatic tilt motor (M), comprising a motor pump aggregate ( 8 ) connected to the hydrostatic rotation and tilt motors (M, M′) and a control system comprising valve components at least for a tilt control, the control system containing pressure controlled blocking valves or load holding valves (LHV A , LHV B ) in working lines (A, B) at least of the at least one hydrostatic tilt motor (M), wherein for automatically adjusting the protected position (S) of the carrier (T) a suction line (N) is provided at the side of the hydrostatic tilt motor (M) facing to the blocking valves or load holding valves (LHV A , LHV B ), that the suction line (N) is adapted to be controlled open only pressure dependently in case of a power switching off condition and/or an electrical power breakdown, that the suction line (N) is controlled by a monitoring solenoid ( 18 ) between an open state and a closed state, that between the hydrostatic tilt motor (M) and the blocking valves or load holding valves (LHV A , LHV B ) the working lines (A, B) are interconnected by a suction path ( 23 ), that a discharge line ( 26 ) branching off from the suction path ( 23 ) is deviating the blocking valves or load holding valves, that a respective pilot pressure operated multi-way seat valve ( 19 , 20 ) is arranged in the suction path ( 23 ) and in the discharge line ( 26 ), the respective multi-way seat valve ( 19 , 20 ) being pilot pressure operated with pilot pressures taken from the suction path ( 23 ) and the discharge line ( 26 ), that a pilot circuit of both multi-way seat valves ( 19 , 20 ) is connected by an unloading branch ( 31 ) to the discharge line ( 26 ), and that a solenoid seat valve ( 22 ) is arranged in the unloading branch ( 31 ), the solenoid seat valve ( 22 ) having the monitoring solenoid ( 18 ) as a valve actuator for bringing the solenoid seat valve ( 22 ) into a blocking position.