| 摘要 |
PROBLEM TO BE SOLVED: To provide an elastic body for the opening cut-off device capable of not only achieving excellent workability but also preventing the deterioration of water cut-off effect due to its breakage. SOLUTION: This elastic body 20 is incorporated into the opening cut-off device to cut off water by sealing a section between a hole drilling rod 50 for drilling a hole in the ground and an opening of an external pipe 51 guiding the hole drilling rod 50. This elastic body 20 has a cylindrical shape allowing the hole drilling rod 50 to pass through it, has an upper face 21a and a lower face 21b which are gradually and downward inclined toward an inner peripheral side, protrudes onto the inner peripheral side when it is pressed from above, and is pressed on an outer peripheral face of the hole drilling rod 50. COPYRIGHT: (C)2009,JPO&INPIT
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