Title:
【発明の名称】縦穴掘削機におけるケリーバーの押込み力調整装置
Document Type and Number:
Japanese Patent JP2832452
Kind Code:
B2
Inventors:
KATO YOSHIO
Application Number:
JP11003789A
Publication Date:
December 09, 1998
Filing Date:
April 29, 1989
Export Citation:
Assignee:
KATO SEISAKUSHO KK
International Classes:
E21B3/02; E21B19/08; (IPC1-7): E21B3/02; E21B19/08
Domestic Patent References:
| JPS58800A |
Attorney, Agent or Firm:
Misono Yoshiyuki