Document Type and Number:
Japanese Patent JPS57500742
Kind Code:
A
Application Number:
JP50049181A
Publication Date:
April 30, 1982
Filing Date:
June 02, 1980
Export Citation:
International Classes:
E21B1/02; B25D17/24; B25D17/28; B25J19/00; (IPC1-7): E21B1/02; B25D17/24; B25D17/28