Hydraulic advancing mine support system - includes integral relief and pressure limiting valves controlling lifting and lowering of telescopic sections

摘要

The advancing mine support system uses telescopic members which include a foot (2) for contact with the ground and an upper part (3) which can be connected to further similar sections. The uppermost section carries a valve (9) at the top for connection to a setting gun, and above this is a fitting (14) for attachment to an overhead beam, along which it can slide. The valve system ensures that the foot is lifted clear of obstacles during advance. Between the inner tube (3) and the outer tube (2) is an annular space (7) forming a chamber for hydraulic fluid. Projecting from the top of the outer tube is a housing (15) with a relief valve (16) and a pressure, limiting valve (17) controlling a channel (18) communicating with this annular space. These are connected to an external valve block.