MULTISTAGE TUNNEL BORING MACHINE

摘要

PROBLEM TO BE SOLVED: To reduce the size and weight and manufacturing cost of a device in a multistage tunnel boring machine and to facilitate the boring of a tunnel changed in diameter in the middle. SOLUTION: A first front drum 12 is connected to a first rear drum 13 through a spherical bearing 14 to constitute a first excavator body 11. A second excavator body 15 is constituted by a second front drum 17 fitted to the circumferential part of the front drum 12 and a second rear drum 19 fitted to the circumferential part of the rear drum 13, and a third excavator body 20 is constituted by a third front drum 22 fitted to the circumferential part of the front drum 17 and a third rear drum 24 fitted to the circumferential part of the second rear drum 17. A broken jack 28 is interposed between the first front drum 12 and the first rear drum 13, whereby the front drums 12, 17 and 22 and the rear drums 13, 19 an 24 are integrally bendable by the spherical bearing 14.