Document Type and Number:
Japanese Patent JPH0242726
Kind Code:
Y2
Application Number:
JP914385U
Publication Date:
November 14, 1990
Filing Date:
January 28, 1985
Export Citation:
International Classes:
E01C23/09; E01C23/12; E21B3/02; (IPC1-7): E01C23/09
Next Patent: JPH0242727