Advance mechanism for a mine roof support unit

摘要

The invention relates to an advance mechanism for a roof support unit to be used in a longwall face of a mineral mining working. The advance mechanism comprises a hydraulic advance ram and guide means constituted by a guide rod means and a guide rail. One end of the guide rod means is attached to a conveyor extending along the longwall face, the other end of the guide rod means being attached to a guide element. The guide rail extends slidably through a guide aperture in the guide element and is pivotally attached to the floor sill of the roof support unit for pivotal movement in a vertical plane perpendicular to the longwall face. The hydraulic advance ram is attached to the guide element and acts on a member fixed to the floor sill.