Patent ID: 8210774
Filing Date: 2012-07-03
Classification: E21D

Abstract:
1. A boring machine for boring a tunnel from a launch pit to a target pit along a desired boring direction and simultaneously installing a selected one of a plurality of differently-sized product casings in the tunnel, in which each product casing of a selected size has a product casing longitudinal axis, a product casing inside surface, a product casing outside diameter and a product casing inside diameter, wherein the boring machine comprises: (a) an internal casing: (b) an adjustable support assembly that is adapted to be located between the outside surface of the internal casing and the inside surface of the selected one of the differently-sized product casings for maintaining the coincidence of the internal casing longitudinal axis with the product casing longitudinal axis; (c) an auger which: (d) a rotational mechanism which is operationally connected to the auger; (e) a pusher mechanism which is adapted to advance the selected product casing, the internal casing and the auger; (f) a plurality of cutter heads, each of which: (g) which includes means for directing material cut by the cutter blades into the internal casing so that rotation of the auger will convey such material towards the rear end of the auger within the internal casing; (h) a front bulkhead that is located behind the cutter head; (i) a steering head that is operated to change the direction of the cutter head, said steering head having an inside surface; (j) a guidance assembly comprising: