Automatic walking tunnelling wall shield

摘要

The shield is for use at the junction between face and tunnel in an underground coal-mine, having an inner shield (13) and two outer ones (12,14) coupled together and sliding parallel to the inner one. A roof cowl (2) is split in the longitudinal direction, and on it a protective wall (3) hinges. Hydraulic telescopic rams (5,6) acts between the floor skids (4) and the cowl and form part of the walking mechanism (9). The cowl-sections for the inner and outer shields have a top guide (15) limiting the distance for which they can be inserted. This allows sliding of the inner shield in the guiding portions of the outer ones, and of the latter in the guiding portions of the inner one under the action of the walking mechanism and positively lifts the skids from the floor. The guide can be arranged to retract the cowls for roughly 200 mm and to lift the skids for roughly 1000 mm.