| 摘要 |
PROBLEM TO BE SOLVED: To provide a backing preventing apparatus for preventing backing or backward pressing of a propelling pipe row, the backing being generated at the time of installing propelling pipes in the ground during propelling work, and to provide a bearing apparatus for preventing the propelling pipe from bending and deforming. SOLUTION: In formation of the backing preventing apparatus, first, an annular body is fixed to the periphery of the propelling pipe at the rear of a starting shaft wall. The annular body has an inner diameter larger than the outer diameter of the propelling pipe and has a trapezoidal cross section because an inner surface of the annular body is inclined rearward to contract the diameter thereof. Then, wedge bodies are inserted from the front into a gap between the annular body and the propelling pipe at a plurality of locations at circumferential intervals. Each wedge body has a trapezoidal cross section because its upper surface is inclined downward to reduce its size. Thus, the backing preventing apparatus prevents the propelling pipe row at the front from returning backward at the time of connecting another propelling pipe to the pipe row. Further, the bearing apparatus is comprised of telescopic means which are arranged on an inner surface of the propelling pipe at locations opposed to the wedge bodies of the backing preventing apparatus, for abutting on the respective wedge bodies by means of bearing plates each having almost the same area as that of the wedge body. COPYRIGHT: (C)2003,JPO
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