Patent ID: 8500370

Claim:
Excavation and compaction equipment for the construction of piles comprising a drilling rod rotating around a rotation axis and a tool mounted at a lower end of the drilling rod; the tool comprising: a hollow central shaft provided at its lower end with a door for the outlet of the concrete; at least a screw integral with the shaft; means for compacting positioned along the screw; a base of substantially semicircular shape at the lower end of the screw; at least a plate of a shape that superimposes under the base and rotates relatively around the shaft for alternatively assuming an open position, in condition of excavation wherein the plate superimposes on the base, and a reclosed position, in condition of compaction wherein the plate forms a surface substantially circular with the base; excavation teeth fixed to the lower end of the tool; at least an additional tooth constrained to the plate so that during at least the phase of casting, the additional tooth is outside an excavation diameter of the tool in the condition of compaction; the additional tooth being movable between two extreme positions, wherein a first one of the two positions of said tooth is inside the excavation diameter of the tool in the condition of excavation and a second one of the two positions is outside the excavation diameter of the tool in the condition of compaction; and wherein the tooth rotates between the two extreme positions, the equipment being provided with means for releasably blocking the tooth in said two extreme positions.