PROCEDE DE FORAGE AVEC TUBAGE SIMULTANE ET RECUPERATION DE L'OUTIL DE ROTATION A LAMES

摘要

The tool has a variable opening which allows it to be closed at the end of drilling and recovered by retracting it through the tube which stays in place. Part (1) of the drilling tool is welded or screwed onto the tube and contains metal inserts which engage in the bayonet fitting (3) welded to the bladed tool. The whole assembly is retracted at the end of the operation. Bladed drilling tools are used to insert a tube into the ground. The drilling operation requires a diameter greater than that of the tube and the tool is lost at the end of drilling.