Document Type and Number:
Japanese Patent JPS6239191
Kind Code:
Y2
Application Number:
JP9211581U
Publication Date:
October 06, 1987
Filing Date:
June 22, 1981
Export Citation:
International Classes:
E21B10/44; E02D17/06; E21B3/02; E21B10/42; E21B17/22; (IPC1-7): E21B17/22; E02D17/06