Document Type and Number:
Japanese Patent JPS613983
Kind Code:
Y2
Application Number:
JP19462481U
Publication Date:
February 06, 1986
Filing Date:
December 29, 1981
Export Citation:
International Classes:
E21C37/26; E21B1/04; E21B10/36; E21C37/02; (IPC1-7): E21C37/02
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