Title:
BORING ROD
Document Type and Number:
Japanese Patent JP2958473
Kind Code:
B2
Abstract:
PURPOSE: To transmit rotation and impact energy to a ring bit via an inner bit to reduce energy loss of torque and impact force so as to enhance drilling capacity, reduce drilling resistance of an outer pipe, decrease deformation and distortion, and thereby prolong a service life.
CONSTITUTION: A double pipe composed of an inner pipe 2 and an outer pipe 3 is connected to an adapter 1 of a head part for receiving rotation and impact force in such a manner that the outer pipe 3 is freely rotatable, and an inner bit 4 is attached to a lower end of the inner pipe 2. An internal thread 5 of a specified length is cut in the direction opposite to drilling rotation at a lower end of the outer pipe 3, and an annular ring bit 6 is arranged outside of the inner bit 4. An external thread 7 of a specified length cut at an upper part of the ring bit 6 is completely screwed into the internal thread 5 of the outer pipe 3 so that screwing may not exceed the thread length. A bit side wall is shaped so as to engage the ring bit 6 with the inner bit 4 in rotation, and an impact face 9 abutting on a stepped part 8 of the ring bit 6 in the vertical direction is provided in the inner bit 4.
Inventors:
UEDA MASAO
Application Number:
JP6470594A
Publication Date:
October 06, 1999
Filing Date:
March 07, 1994
Export Citation:
Assignee:
KAMEYAMA KK
OOBAYASHIGUMI KK
OOBAYASHIGUMI KK
International Classes:
E21B10/36; E21B6/00; E21B6/02; E21B7/20; (IPC1-7): E21B7/20; E21B6/00; E21B10/36
Domestic Patent References:
| JP355386A | ||||
| JP4146393A | ||||
| JP533589A | ||||
| JP598885A |
Attorney, Agent or Firm:
Shoshiro Tojima
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