Hydraulic roof support system for mines - has lowered roof support unit advanced through space between adjoining set units

摘要

The hydraulic roof support system for longwall faces in mines includes a number of support units arranged in rows behind each other and each consisting of at least two props supporting one roof bar. The length of the roof bars of the support units is shorted or lengthened by advancing a support unit with lowered and shortened roof bar from rear end of the row through space between props and roof bars of adjoining set support units. The roof bar ends of the support unit are pivotably mounted on pins positioned parallel with the row of supports.