Document Type and Number:
Japanese Patent JPS5629437
Kind Code:
Y2
Application Number:
JP3645478U
Publication Date:
July 13, 1981
Filing Date:
March 22, 1978
Export Citation:
International Classes:
E21B10/02; E21B25/00; E21B25/04; (IPC1-7): E21B25/00; E21B10/02