Document Type and Number:
Japanese Patent JPS5651886
Kind Code:
U
Application Number:
JP13326979U
Publication Date:
May 08, 1981
Filing Date:
September 28, 1979
Export Citation:
International Classes:
E21B1/26; E21B1/00; E21B21/00; (IPC1-7): E21C3/20; E21C5/00