Multiple telescopic prop

摘要

Multiple telescopic props in the hydraulic support system in underground mining and tunnelling are protected by non-return valves with integrated overpressure stage. On account of their spatially favourable design, the non-return valves can be advantageously accommodated inside the individual telescopic stages or the tube plates of the individual telescopic stages. The conventional plunger of non-return valves of this type has a blind bore with a valve body displaceable therein against the spring force of a spring arranged at the end. The valve body is provided with an axial bore and radial bores which branch from the axial bore, make the connection to the pressure space of the first telescopic stage and correspond to bores in the plunger. <IMAGE>