Drill for civil engineering has the chisel bit in a sliding bush contained within the blind opening of a holder to be forced out by fluid between the bush base and the bottom of the opening

摘要

The drill for civil engineering has at least one chisel (11) with a round shaft, rotating in a sliding bush (12) in a beaker shape with a base (21). The holder (13) has a blind opening (25) to take the bush, with a defined hollow zone (15) between the base of the bush and the bottom (26) of the opening. A fluid is passed into the hollow zone from a connection (14) to force the bush out of the opening.