Hydraulic system is for damping vibrations in load-bearing crane and comprises manoeuvre valve for operation of piston cylinder unit with lowering side and lifting side

摘要

The hydraulic system is for damping vibration in a load-bearing crane and comprises a manoeuvre valve for operation of a piston cylinder with a lowering side and a lifting side. Also incorporated is a unit for registration of pressrue in the piston cylinder unit and for signal generation. This unit is in the load bearing valve of the oven center type which is regulated by the generated signal via a signal pressure conduit from the piston cylinder unit lowering side. A safety valve is regulated by a signal pressure via a control pressure conduit from the piston cylinder lifting side. The system includes a cut-off valve fitted to the signal pressure conduit, which it closes when the pressure in the cylinder exceeds a previously determined value at which the pressure in the control pressure conduit increases and opens the safety valve.