HYDRAULIC PROP Russian patent published in 1996 - IPC

FIELD: mining, hydraulic props for powered supports. SUBSTANCE: safety valve 5 is made in the form of cone, and provided with seat comprising covering member 10 and inner member 11. Lower part of member 10 has slot 13 and lug 14 that extends inside the slot. Lower part of member 11 has a ledge placed in slot 3 of the member 10 so as to interact with lug 14. Turning 15 of outer surface of member 10 with L-shaped rest 16 with extended support lug 17 on its horizontal shelf. Inner member 11 of the seat is installed on it with its inner surface. Actuating cavity "m" limited by butt surface of cylinder 4 foot is over safety valve 5 in the seat that is permanently open to piston cavity by valves 18 made in the seat. Reliable operation followed by safety valve closing is provided due to shock loading. EFFECT: high reliability. 2 cl, 1 dwg