| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a middle pushing device for dispersing driving force for driving and burying a boring machine and a propulsion pipe column at an intermediate part of the propulsion pipe column without concentrating it on the last end of the propulsion pipe column. <P>SOLUTION: A front annular body 2 has a cylindrical front step part 3 whose diameter is made smaller than an outer diameter of a propulsion pipe 12 at a front distal end part, and has a cylindrical front cylinder 4 of the almost same diameter as the pipe outer diameter extended at the back thereof, and the front step part 3 is inserted into a collar of the pipe. A back annular body 5 is formed by providing a cylindrical back step part 6 whose diameter is made smaller than the pipe outer diameter, providing ring-like flanges 8 on both front and back ends of the back step part 6, providing a notch on a part to install a plurality of middle pushing jacks 9 in a circumferential direction of an inner peripheral surface of the back step part 6, placing concrete of the almost same thickness as a pipe wall body on the other, installing the plurality of middle pushing jacks 9 at the notched part, and extending a cylindrical back cylinder 7 of the almost same diameter as the pipe outer diameter at the back of the back flange, and the back step part 6 is installed from the back of the front cylinder 4 of the front annular body 2. A step part of a pipe whose diameter is made smaller than the outer diameter of the propulsion pipe 12 at the distal end is inserted into the back cylinder 7 of the back annular body 5. <P>COPYRIGHT: (C)2013,JPO&INPIT |
