Atlas Copco Construction and Mining Technique Ab

Jan H Forsberg

Carl S Hartwig

Nils M Astrand

Tunnel boring machine comprising a number of swingable arms (11,12,13,14) provided with boring tools (41,42,43,44) for the working of the tunnel wall outside its normal diameter. The arms may be swung outwardly into an active position or retracted into an inactive position. These tools may be independently actuated and facilitate the insertion of steel supporting arcs into the excavated area.

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Enebyberg, Sweden

Jan H Forsberg