| 摘要 |
PURPOSE:To improve the linear propulsion property and curve propulsion property in the ground and improve the steering performance by advancing a propulsion body so that the protruded quantity of an advance section from a propulsion head main body is kept larger at the time of linear propulsion than that at the time of curve propulsion. CONSTITUTION:A propulsion facility 12 pinching a propulsion body 1 and thrusting it into the ground for underground propulsion is provided. For linear propulsion, pressure oil is fed to a cylinder chamber while the thrusting action is stopped. The rotation of an advance section 6 is stopped, and it is largely protruded in the axis X direction of the propulsion body 1 in the same attitude. Pressure oil is continuously fed to keep the protruded state of the advance section 6, and the propulsion body 1 is thrust into the ground from the base end side by the propulsion facility 12 for propulsion. For curve propulsion, the quantity of the pressure oil fed to the cylinder chamber is made smaller than that at the time of linear propulsion, and the protruded quantity is reduced while the thrusting action by the propulsion facility 12 is stopped. The oil feed is stopped, and the whole propulsion body 1 is thrust into the ground while the protruded state of the advance section 6 is kept constant to perform curve propulsion with a small turn. |
