To remove an excavating head into a start position for replacement in a short time without removing a buried pipe when replacing the excavating head halfway in laying the buried pipe.
This underground jacking device 1 comprises a jacking machine 20; a leading body 2 arranged at the rear part; an inner cylindrical body 3 inserted in the leading body 2; a screw 4 arranged in the inner cylindrical body 3; and the excavating head 5 fixed to the tip of the screw 4. The excavating head 5 has a head body 8 having an outer diameter smaller than the inner diameter of the leading body 2 and larger than the outer diameter of the inner cylindrical body 3, and a plurality of turning plates 10 or the like formed with excavating bits 15 fixed thereto, and mounted to the head body 8. The plurality of turning plates are arranged to move so that the respective tips project outward from the outer periphery of the leading body 2 due to excavating resistance when the head body 8 is normally rotated and to move inward from the outer periphery of the head body 8 due to excavating resistance when the head body 8 is reversely rotated.
IMAI TSUTOMU
YONEMORI KIYOHARU
SAN SHIELD KK
| JP2001271580A | 2001-10-05 | |||
| JP2001049989A | 2001-02-20 | |||
| JP2001214690A | 2001-08-10 | |||
| JPH0250499U | 1990-04-09 |
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