| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem of complicating the constitution of a boring machine as a whole because rotation resistance increases, energy consumption increases and it is hard to improve support rigidity for supporting rotary cutter heads in constitution of providing and rotating a casing or the like of gears projecting deep into a chamber of a shield machine for excavating a tunnel with an oval cross section. SOLUTION: The shield machine is provided with a body 1 with an oval cross section; a circular plate member 17 mounted on a front end side portion of a shield machine main body 3; a first rotating drive mechanism 18 for rotationally driving the circular plate member; a pair of swing arms 19 rotatably supported to the circular plate member; a pair of second rotating drive mechanisms 20 for rotationally driving the pair of swing arms; a pair of head support members 19a firmly fixed to the tip parts of the swing arms; a pair of rotary cutter heads 4 each having a diameter which is half the short diameter of oval shape of the cross section of the body and rotatably mounted to each of the head support members; and a pair of third rotating drive mechanisms 21 rotationally driving the pair of rotary cutter heads around third axes. COPYRIGHT: (C)2008,JPO&INPIT |
