Lost drill crown, for a drilled or injected anchor in soft ground or rock, has structured hard metal chisel cutters with angled edges, to drill effectively through different layers

摘要

The lost drill crown (1), for a drilled or injection anchor in soft ground or rock, has at least one outlet opening of a flushing channel. The drill head has a multiple chisel structure at aligned radials, symmetrical to the center axis, with hard metal cutters (2) on different steps with different radial alignments. An angled edge (3) of the cutters is at right angles to the vertical axis.