Title:
DRILLING BIT
Document Type and Number:
Japanese Patent JP3672638
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To prevent injected water from percolating through a stratum to the utmost so as to prevent excessive breaking of the wall of a drilled hole.
SOLUTION: A drilling bit 10 is provided with a double tube comprising an outer casing 2 and an inner rod, and the knife edge 6 of the bit is provided with a first through hole 18 communicated with the inner rod 3 and a second through hole 19 communicated with the space between the inner rod 3 and the outer casing 2. The drilling bit 10 comprises a cylinder 16 for surrounding the periphery of the knife edge 6. The tip of the cylinder 16 is formed like a sawtooth 21, whereby at the time of drilling, the tip of the cylinder 16 bores into the ground earlier than the knife edge 6 to block up the periphery of the knife edge 6 so that injected water is prevented from percolating through the peripheral ground so as to prevent excessive breaking of the wall of the drilled hole.
Inventors:
Yamamoto Ginichirou
Application Number:
JP25515795A
Publication Date:
July 20, 2005
Filing Date:
October 02, 1995
Export Citation:
Assignee:
Altec Co., Ltd.
International Classes:
E21B10/02; E21B10/60; (IPC1-7): E21B10/60; E21B10/02
Domestic Patent References:
| JP5042392U | ||||
| JP8035386A | ||||
| JP6141832Y2 |
Attorney, Agent or Firm:
Bunji Kamada
Higashio Masahiro
Torii Kazuhisa
Higashio Masahiro
Torii Kazuhisa