Valve arrangement for actuating the telescopic cylinder of a tipper of a lorry

摘要

For actuating the telescopic cylinder of a tipper of a lorry, a proportional directional control valve is provided in conjunction with a pressure balance which opens towards the tank and a pressure cut-off valve in the control line, leading to the load pressure, for the pressure balance. The valve arrangement is connected to a constant pump. The working speed of the telescopic cylinder is independent of the load to be lifted and of the drive speed of the constant pump. When a predetermined load pressure is reached, the pressure cut-off valve responds and the load pressure acting on the pressure balance in the closing direction is reduced with respect to the tank so that the pressure balance opens and the pump delivery quantity flows back to the tank.