Document Type and Number:
Japanese Patent JPS62169086
Kind Code:
U
Application Number:
JP5402786U
Publication Date:
October 27, 1987
Filing Date:
April 10, 1986
Export Citation:
International Classes:
E21B7/02; E21B6/00; E21B6/02; (IPC1-7): E21B6/00; E21B7/02
Domestic Patent References:
| JPS5934392A | 1984-02-24 | |||
| JPS59220591A | 1984-12-12 | |||
| JPS59141686A | 1984-08-14 |