Improvements bringest the drill bits and the containers by percussion drilling

摘要

The subject of the present invention is a drilling bit or bucket intended to be used jointly with a guiding tube 12. According to the invention, this drilling bit or bucket comprises, at its lower part, retractable boring teeth 8 or 8a which are subjected to the action of means 9 or 9a tending to hold them in a position in which they project out of the bit or bucket. IMAGE