Document Type and Number:
Japanese Patent JPS6239177
Kind Code:
Y2
Application Number:
JP4989582U
Publication Date:
October 06, 1987
Filing Date:
April 08, 1982
Export Citation:
International Classes:
E21B19/086; E21B3/00; E21B3/035; E21B19/00; E21B19/08; (IPC1-7): E21B3/00; E21B19/08