Document Type and Number:
Japanese Patent JPS557514
Kind Code:
B1
Abstract:
A borer comprises a hammer, a spindle connected to rotate with a rotatable table, and a vibrator connected between the hammer and a support for vibrating the hammer. The spindle is free to rotate with respect to the support. A flexible coupling is arranged between the support and the table.
Application Number:
JP4267872A
Publication Date:
February 26, 1980
Filing Date:
May 01, 1972
Export Citation:
International Classes:
E21B1/20; E21B7/24; (IPC1-7): E21B6/00