| 摘要 |
<p>PURPOSE:To prevent the buckling or the like of a replaced pipe from being generated by composing a cylindrical body, of a front cylindrical body and a rear cylindrical body arranged slidably in the front and rear directions, and by advancing the front cylindrical body to the rear cylindrical body with an extruding jack, to break a ready-laid pipe with a breaking edge. CONSTITUTION:A cylindrical body 1 is composed of a front cylindrical body 3 and a rear cylindrical body 4 which are formed with each other slidably in the front and rear directions, and on the cylindrical body 3, a breaking edge 5 with each pair of long edges 5b and short edges 5c formed in a crossed shape is fitted. In the cylindrical body 4, an extruding jack 7 is set. After that, from a starting shaft, the edge 5 is inserted into a ready-laid pipe 6 and after that, via the cylindrical body 4, the whole cylindrical body 1 is propelled forward by a propelling jack, and a replaced pipe 2 is inserted into. Then, by the jack 7, the only cylindrical body 3 is extruded, and the pipe 6 is broken, and the jack 7 is shrunk, and by the propelling jack, the new pipes 2 are pushed into in order and are laid. Accordingly, the buckling or the like of the replaced pipes can be prevented from being generated.</p> |
