Hydraulically switchable directional control valve

Hydraulical switchable distribution valve in particular for shield supports in underground mining, with:

• a high pressure port, a load port, a return port, and a control pressure port for hydraulic fluid;
• a valve piston, axially displaceable in a location hole of a valve seat mounting, which at its open end face is connected to the load port, which comprises a radial aperture and which when in contact with a sealing seat on the valve seat mounting side blocks off the load port from the high pressure port;
• a control piston in a control piston guide, which can be displaced by means of a force exerted by a control pressure at the control pressure port, by means of which the return port, as a function of the position of the control piston, can be connected with the load port or can be blocked off from the load port and the high pressure port, wherein
• the valve piston comprises a second radial aperture, displaced towards the end face relative to the first radial aperture, and that the first radial aperture can be closed by the control piston with the arrival of the control piston at an intermediate position between an initial position and an end position.