Document Type and Number:
Japanese Patent JPS5524232
Kind Code:
Y2
Application Number:
JP3018875U
Publication Date:
June 10, 1980
Filing Date:
March 07, 1975
Export Citation:
International Classes:
E21B1/26; E21B1/00; E21B1/12; E21B6/08; (IPC1-7): E21C3/20