Machine for making underground galleries

摘要

The invention concerns an improved machine for making underground galleries. This machine comprises a shield consisting of two mutually movable parts, a forward knife casing 1 supporting on its inside a digging device 3 and a rear assembly skirt 2 acting as a guide means for a thrust ring 10. The knife casing and the assembly skirt are mutually connected by a slack fastening system allowing them to pivot with respect to each other in such a manner that their longitudinal axes form an adjustable angle. The machine of the invention applies to making underground galleries provided with coverings bracing the earth; it makes possible marked curves without the requirement of out-of-path earthworks.