| 摘要 |
PROBLEM TO BE SOLVED: To achieve excavation when making a sharp turn by providing a spline mechanism along the direction of the axis of an excavator, and connecting using a universal joint the portion between time drive source and the drive shaft of a cutter head to a rear shell connected to the rear of the excavator. SOLUTION: To make a sharp turn, a rear gripper is made to abut to a drilled pit wall surface by means of one rear gripper jack 11, and a rear shell 3 is fixed inside the pit. Next, a front gripper mainly expands a gripper located on the opposite side to expansion of the rear gripper, and deflects the excavator (t) side within the gateway. In this case, contact with the pit wall is made in such a way that a deflection angle is formed between the excavator (t) and the rear shell (u). Thereafter, when excavation is performed using a propulsion jack 4, the propulsion jack 4 is expanded to provide the projecting force of a gripper jack 9 such that the front gripper advances while slipping over the pit wall. Therefore, the propulsion jack 4 can excavate by a predetermined stroke as a cutter head 1 advances. |
