Title:
EXCAVATION TOOL
Document Type and Number:
WIPO Patent Application WO/2016/027737
Kind Code:
A1
Abstract:
This excavation tool comprises: a casing pipe, a large-diameter ring bit disposed coaxially on a distal end side of the casing pipe, and a pilot bit inserted into the ring bit through the inside of the casing pipe. A bit head that expands in diameter when rotated in a tool rotation direction during excavation is provided to an outer circumferential part at the distal end of the pilot bit. Provided to the ring bit are: an engaged part that engages with the expanded bit head in the tool rotation direction; and a first abutting part capable of abutting the bit head in the axial direction. A second abutting part capable of abutting on a small diameter part on an inner peripheral part at the distal end of the casing pipe is provided to an outer peripheral part at the rear end of the pilot bit. A third abutting part capable of abutting on a rear end face of the ring bit is provided to a distal end part of the casing pipe.
Inventors:
NAKAMURA KAZUYOSHI (JP)
TAKATSUKI HIROKI (JP)
TAKATSUKI HIROKI (JP)
Application Number:
PCT/JP2015/072781
Publication Date:
February 25, 2016
Filing Date:
August 11, 2015
Export Citation:
Assignee:
MITSUBISHI MATERIALS CORP (JP)
International Classes:
E21B10/32
Foreign References:
| JP2013122112A | 2013-06-20 | |||
| JP2008038444A | 2008-02-21 | |||
| JP2001146886A | 2001-05-29 |
Attorney, Agent or Firm:
SHIGA Masatake et al. (JP)
Masatake Shiga (JP)
Masatake Shiga (JP)
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