Document Type and Number:
Japanese Patent JPS54118402
Kind Code:
U
Application Number:
JP1481478U
Publication Date:
August 18, 1979
Filing Date:
February 07, 1978
Export Citation:
International Classes:
E21B10/02; (IPC1-7): E21C13/02; E21B9/16
Domestic Patent References:
| JPS4425239Y1 | 1969-10-23 | |||
| JPS4845274U | 1973-06-13 |