PERFECCIONAMIENTOS EN ESCUDOS EXPANSIBLES PARA ABRIR CAVIDA-DES SUBTERRANEAS.

摘要

Shield apparatus for use in tunnelling or mining employs two spaced-apart arcuate frames each composed of a pair of segmental components interconnected at the roof by means of telescopic guides and a central pivot joint. The roof pivot joint between the components of each frame is disposed inside a hollow support and hydraulic rams connect the components to the support. At their lower ends the components of each frame are supported on floor structures connected together with a floor beam. Pivot joints are again formed between the floor structures and the frame components and further telescopic guides and hydraulic rams are arranged between the frame components and the floor structures. The frame components, which may support elongate drive members on their exterior, are adjustable with the aid of the hydraulic rams about the pivot joints to expand or contract the frames.