Title:
DRILLING TOOL
Document Type and Number:
Japanese Patent JP2018062788
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To prevent a pilot bit from being removed when torque and striking force are applied to a casing pipe.SOLUTION: A drilling tool is provided with: a casing pipe 1 which is rotated along axis O and to which striking force to the tip side is transmitted, a ring bit 2 which is attached to a tip of the casing pipe, and a pilot bit 3 which is inserted into the inner peripheral part of the ring bit 2. At the inner peripheral part of the ring bit 2, formed are a recessed groove 5 extending in axis O direction, opening at least toward a rear end, an engaging groove 6 extending from the recessed groove 5 at least in a direction of rotation opposite from that of the casing pipe 1 when drilling, and a first abutting surface 7b facing the tip side and a second abutting surface facing the direction of rotation. At the outer peripheral part of the pilot bit 3, formed are a protrusion 8 which is inserted into the engaging groove 6 from the recessed groove 5 and can engage at least to the tip side in axis O direction, and a first abutted surface 9a on which the first abutting surface 7b can abut with the protrusion 8 engaged by the engaging groove 6 and a second abutted surface on which the second abutting surface can abut.SELECTED DRAWING: Figure 1
Inventors:
NONAMI MASATOSHI
IWATA AKIHISA
NAKANISHI YASUTAKA
NAKAMURA KAZUYOSHI
TOMITA YASUTAKA
IWATA AKIHISA
NAKANISHI YASUTAKA
NAKAMURA KAZUYOSHI
TOMITA YASUTAKA
Application Number:
JP2016201565A
Publication Date:
April 19, 2018
Filing Date:
October 13, 2016
Export Citation:
Assignee:
NONAMI MASATOSHI
YUBIRON FACT CO LTD
TOYO KIKAKU KK
MITSUBISHI MATERIALS CORP
YUBIRON FACT CO LTD
TOYO KIKAKU KK
MITSUBISHI MATERIALS CORP
International Classes:
E21B10/26
Domestic Patent References:
| JPH0921129A | 1997-01-21 | |||
| JP2000352290A | 2000-12-19 | |||
| JP2013124535A | 2013-06-24 |
Foreign References:
| EP2339109A2 | 2011-06-29 |
Attorney, Agent or Firm:
Masatake Shiga
Mitsuo Teramoto
Yasushi Matsunuma
Fumihiro Hosokawa
Kazunori Onami
Mitsuo Teramoto
Yasushi Matsunuma
Fumihiro Hosokawa
Kazunori Onami