Document Type and Number:
Japanese Patent JPH02120583
Kind Code:
U
Application Number:
JP2650389U
Publication Date:
September 28, 1990
Filing Date:
March 08, 1989
Export Citation:
International Classes:
E02D7/00; E21B6/00; E21B6/02; E21B7/00; E21B7/02; (IPC1-7): E21B6/00; E02D7/00; E21B7/02
Domestic Patent References:
| JPS6342049A | 1988-02-23 |