HYDRAULIC PROP Russian patent published in 2003 - IPC

FIELD: mining; applicable in mines with dynamic loads hazard. SUBSTANCE: hydraulic prop has cylinder with head and rod ends and accommodating movable rod, safety valve and spring-loaded piston having two channels and bore in lower part closed by cover. Safety valve is made in form of slide valve connected with rod and installed for longitudinal motion in spring-loaded piston, whose bore surface, slide valve and cover form closed space. Channels in piston are made for periodic communication of rod end via one of channels with closed space, and via other channel, with head end. Piston is spring-loaded with ring spring installed in rod end between piston and internal end of rod head. Slide valve is connected with rod with help of bar having shoulder and secured in rod head. Rings of ring spring are permanently closed under fluid weight in cylinder cavity and force of coil spring located between spring-loaded piston and bar shoulder. EFFECT: higher operate reliability of hydraulic prop due to dissipation of energy part into irreversible friction work. 1 dwg