DE2936060

The earth borer, (100) produces bore holes for cast-in-place concrete piles. It consists of a hollow drill head of conical shape with spiral steps on its outside. A drill tube is inserted in its open end where it engages serrated inner teeth with serrated teeth on its leading edge. Packing material seals the joint between drill tube and drill head. After completing a hole and pouring the concrete, the drill tube can be extracted.S The hollow drill head (2) has spiral turns along its conical contour and the same wall thickness except near the top rib (4) where a thicker wall permits inner teeth (3) below a collar (5). The drill tube (1) has teeth (8) at the end which engage the teeth (3). Suitable sealing material (9) fills the gaps between the parts.