HYDRAULIC PROP Russian patent published in 2002 - IPC

FIELD: mining; applicable in mines prone to rock bursts. SUBSTANCE: hydraulic prop includes cylinder, rod with piston, shock absorber installed under rod, valve, slide valve with steps and shank with flange, slide valve body with discharge hole in its wall and vertical guides and connected to cylinder, spring located on slide valve shank between slide valve body and shank flange, weight with stop located in vertical guides of slide valve body and engageable by its lower end with slide valve step, branch pipe communicating cylinder cavities with a cavity of slide valve body, and additional branch pipes connected to cylinder lower part of its above-piston cavity, with spaces between them in height and connected to slide valve body along its length. In initial state of hydraulic prop, holes of branch pipes in slide valve body are overlapped by slide valve made with steps and provided with stepped rack having longitudinal slot for receiving of weight stop having belt whose diameter is larger than width of stepped rack longitudinal slot. Stepped rack is installed in a spaced relation to slide valve steps for disengagement of weight stop from next slide valve step in every burst. EFFECT: higher reliability of protection of hydraulic prop from damage during repeated rock bursts due to discharge of definite amount of fluid from prop cylinder in every rock burst. 3 dwg