| 摘要 |
<p>PURPOSE:To enable the title blade to break a pipe simply with small force, by a method wherein a widening blade forming a V-shaped state narrower than a width of a cutter blade is provided on a position of a cone where the cutter blade meets at right angles with the cone. CONSTITUTION:The tip part of a breaking blade is inserted into a vinyl chloride pipe 7 and the vinyl chloride pipe 7 is deformed into an oval with a cutter blade 3 according as an excavator moves forward. A cutting-off line is formed further on the inside of a vinyl chloride pipe 7 with connecting protrusion 5 provided on the both edges 3a of the blade. When the excavator is moved forward further, after the vinyl chloride pipe 7 has been extended up to the limit, the same is cut off into two with the edge 3a of the cutter blade 3. A cut off vinyl chloride pipe 7' is deformed after a windening blade 6 and core 1 with them. At the time of breaking of the above-mentioned vinyl chloride pipe, which is spread larger than the diameter in a conventional one, while the pipe 7' is being deformed, a connecting protrusion 5 is connected with the beginning end part of cutting-off, therefore, it does not happen that the excavator receives force where the excavator is moved backward through restoring force of the vinyl chloride pipe.</p> |
