REVERSIBLE PERCUSSIVE ACTION MACHINE FOR DRIVING HOLES IN THE GROUND

摘要

A reversible percussive action machine includes a housing accommodating a hammer capable of reciprocating motions under the action of a working fluid under pressure, and a valving member with grooves movably connected to the hammer and provided with members for fixing it relative to the housing in two distribution control positions, particularly one that makes the machine move forward and one that ensures the return travel of the machine. The members for fixing the valving member in a position for the forward travel of the machine is fashioned as an insert movable relative to the valving member and having projections received by the grooves of the valving member. The insert is enclosed by a shell with ports, this shell being secured between the housing and the valving member to be capable of axial displacement.