| 摘要 |
<p>PURPOSE: To enable it to widely correspond to the size of an exiasting pipe and to make the followability and selability of a device improvable by situating a crushing bit in the exiasting pipe to be crushed, and rotating a jack after being expanded wide. CONSTITUTION: A motor is started in operation, rotating two boring cutters 11 and 11, and an outer boundary of an exiasting pipe 10 is bored, thereby forming a tunnel inner wall which is reinforced by two segments 2 and 2. In addition, a body 1 is pushed forward by dint of a reaction made up of pressing the segment 2 with a driving jack 16. Next, if both jacks 3 and 3 are expanded wide at a position where the body 1 is advanced forward as far as the same degree as length of each crushing bit 4, the crusing bit 4 installed in an end of the jack 3 comes into contact with an inner surface of the existing pipe 10. Here the motor 5 is restarted, rotating the jack 3, and the existing pipe 10 is cut and crushed by the four crushing bits 4. At this time, a seal to fill up a clearance between a rotator 13 and the exiasting pipe 10 is installed there, and it is always contacted, under pressure, with the exiating pipe 10, and thus it is desirable that hermetrical-sealability in an inner part of a boring machine be further improved.</p> |
