Drilling tool for making undercuts in pilot drillholes

摘要

An especially resistant drilling tool for making undercuts in pilot drillholes in concrete, rock or the like, with a tubular tool shank (3) to be introduced into the pilot drillhole (18), comprising a cutting tool which can be pivoted out radially with its bit (8) through a lateral orifice (19) of the tool shank (3) by means of a working tappet (11) which is guided axially displaceably inside the tool shank (3) and the butting surface (13) of which bears on a deflecting surface (9) of the cutting tool and of which the end emerging from the tool shank (3) has an impact surface (20) for transmitting axial impacts; in addition to the working tappet (11), there is also provided a return tappet (12), the butting surface (14) of which cooperates with a return surface (10) of the cutting tool and of which the end emerging from the tool shank (3) can be actuated in alternation with the impact movement of the working tappet (11), in such a way that the cutting tool is deflected by an impact on the working tappet (11) and is returned by a subsequent impact on the return tappet (12). <IMAGE>