Abstract: A reversible percussion device, having a casing 1 in which is installed a movable striker and a system for distributing fluid under pressure for causing the striker 4 to move for both forward and rearward movement functions of the device. The system comprises a control member 9 for controlling the distribution of fluid under pressure for both functions, which is movably coupled to the striker 4 and has a mechanism for locking it with respect to the casing 1 in two control positions, corresponding to the two functions of the device. According to the invention, the mechanism for locking the control member 9 in the position enabling the forward movement functions of the device comprises a body 11 movable relative to the control member 9.

Abstract: A machine for driving holes in the ground comprises a cylindrical housing, hammer disposed inside the housing, and an air distribution mechanism. Longitudinal recesses and projections are provided on a portion of the outer surface of the housing at its head end section. The diameter of the cylindrical part of the housing is greater than the diameter of a circle described about the bottoms of the recesses and smaller than the diameter of a circle described about the tops of the projections.

Abstract: A specific feature of the apparatus according to the invention which incorates a percussion unit to a tail piece whereof there is attached a rope connecting to a means of extracting is that fitted into said tail piece coaxially therewith and with a clearance is a ring, the clearance between said ring and said tail piece containing a resilient member with passages reeved wherethrough are the ends of the rope and the inside surface of said tail piece being provided with stops in the body whereof there are also passages for reeving the ends of the rope.

Abstract: The device comprises a hollow cylindrical body, pointed front at its end which device accommodates a striker forming the front working chamber in said body, and has a cylindrical space at its rear end. Said space receives an air-distributing and reversing mechanism, thus forming the rear working chamber. The air-distributing and reversing mechanism has a bushing which is fixed relative to the body, and an axially movable bushing, both bushings being arranged coaxially, spring-loaded in the axial direction relative to each other, and forming a chamber located in the front part of said mechanism, with the chamber communicating with a source of compressed air and intended to move the movable bushing during reversal of the device.