Percussive action machine for making holes in the ground

Claim 1

A percussive action machine for making holes in the ground, said machine comprising: a cylindrical housing; a hammer capable of reciprocations inside said housing; a forward stroke chamber formed in said housing by said hammer; an air-feeding line continuously communicating with said forward stroke chamber; a return stroke chamber alternately communicating with said forward stroke chamber and with the outside; a conduit means for communicating said return stroke chamber with said forward stroke chamber and with the outside, said conduit means positioned in said hammer; a sleeve having an opening communicating with the outside, said sleeve secured in said housing; a tubular control valve movable relative to said hammer and movable within and relative to said sleeve for opening and closing said opening in said sleeve to define with said sleeve an air-distributor; a control valve moving means carried in said hammer for moving said tubular control valve to assume two extreme positions relative to said hammer, in one of which positions said return stroke chamber communicates through said conduit means in said hammer and through said valve in said air-distributor with the outside, whereas in the other extreme position said valve provides communication between said air feeding line and the forward stroke chamber; said forward stroke chamber defined between end faces of said sleeve and said hammer; said conduit means in the form of at least one bore provided in said hammer in line with its axis; said tubular control valve communicating with said conduit means and extending through said forward stroke chamber; at least one hole provided in the wall of said tubular control valve wherethrough said return stroke chamber communicates with said forward stroke chamber and with the outside.