Title:
DEVICE FOR DRILLING HOLE IN BEDROCK
Document Type and Number:
Japanese Patent JP3479754
Kind Code:
B2
Abstract:
PURPOSE: To prevent wear and tear of or damage to a guide rod due to contact with a drilling bit.
CONSTITUTION: A guide rod 60 comprises an axial member 60a, a cylindrical member 60c rotatably fitted on the member 60a, and a cap 60b mounted on an end of the member 60a. The rod 60 is inserted into a hole 17 which has been formed in a bedrock 19 and a drilling rod 4 is rotated to drill a hole. As the distance from a bracket 70 to a drilling bit 3 gradually increases, the rod 4 is bent toward the hole 17 and largely bent when the bedrock 19 is very hard, and hence the peripheral portion 3a of the bit 3 makes contact with the member 60c. Since the member 60c is rotatably supported by the member 60a, the member 60c also is rotated by contact with the bit 3. Thus frictional force between the rod 60 and the bit 3 is extremely small, and hence wear of the rod 60 and the bit 3 rarely occurs and breakage thereof can be avoided.
More Like This:
Inventors:
Toshiro Tsuchiya
Application Number:
JP11930095A
Publication Date:
December 15, 2003
Filing Date:
April 20, 1995
Export Citation:
Assignee:
Fujita Co., Ltd.
Omotogumi Co., Ltd.
Nippon Rock Engineering Co., Ltd.
Toyu Industry Co., Ltd.
Omotogumi Co., Ltd.
Nippon Rock Engineering Co., Ltd.
Toyu Industry Co., Ltd.
International Classes:
E21B19/08; E21B19/24; E21C25/06; (IPC1-7): E21C25/06
Domestic Patent References:
| JP2289788A | ||||
| JP63104B2 |
Attorney, Agent or Firm:
Shigeru Noda
Previous Patent: SURFACE TREATMENT OF STEEL MATERIAL AND AQUEOUS CHROMATING SOLUTION
Next Patent: EXHAUST GAS RECIRCULATION DEVICE
Next Patent: EXHAUST GAS RECIRCULATION DEVICE