Provided is a two-piston hydraulic striking device that has stable operativity. This two-piston hydraulic striking device includes two striking mechanisms for striking one transfer member. Each striking mechanism has a pressure receiving area ratio between the front and rear of a piston thereof set in such a way that the two striking mechanisms have the same cycle time.

A piston for a hammer drill is a flat piston made from sintered steel. The piston can be impregnated with a lubricant.

The invention concerns a rock breaking device comprising a striking cell having at least one actuation chamber, a striking piston, and a hydraulic circuit comprising a hydraulic supply source having a High Pressure circuit and a Low Pressure circuit, and an actuator configured to connect the High Pressure circuit or the Low Pressure circuit to the actuation chamber so as to move the piston in translation in the striking cell in a normal movement area of which the limits are variable depending on the pressure difference between the High Pressure circuit and the Low Pressure circuit, the striking cell comprising depressurizing means configured to control the establishment of hydraulic communication between the High Pressure circuit and the Low Pressure circuit when the striking piston exits a predefined movement area.

The portable power chiseling tool has a tool holder, an electric motor, a striking mechanism and an idle strike catcher. The tool holder can receive a tool and retain it movably on a working axis. The striking mechanism includes an exciter piston, a striker, an anvil and a guide for the anvil. The exciter piston is coupled to the electric motor. The guide guides the anvil on the working axis. The idle strike catcher for the anvil has a conical inner surface facing the anvil. The anvil has an associated end face facing in the striking direction. The end face rests against the conical inner surface when the anvil is in its forwardmost position in the striking direction. The end face of the anvil has a first segment and a second segment in the circumferential direction. The second segment is offset in the striking direction relative to the first segment.

The rotary percussive hydraulic perforator comprises a body; a fitting; a striking piston configured to strike the fitting; a stop piston including a front face facing the fitting and a rear face situated opposite to a rear wall of a cavity receiving the piston stop; and a main hydraulic supply circuit including a high pressure fluid supply conduit and a low pressure fluid return conduit. The body and the stop piston delimit a first control chamber permanently connected to the high pressure fluid supply conduit and configured to bias the stop piston forwards, and a second control chamber configured to bias the stop piston forwards and permanently connected to a low pressure accumulator connected to the low pressure fluid return conduit.

A hammer drill is provided with a hammer mechanism that includes a cylinder having a central axis, a ram having a radial recess slidably mounted within the cylinder, a piston slidably mounted within the cylinder, and a ram catcher. The ram catcher includes a first ring and a second ring surrounding the central axis and forming a groove therebetween, the second ring being located between the first ring and the end of the cylinder. An O-ring that is resiliently-deformable is mounted within the groove and includes an inner side projecting inwardly towards the central axis. When the ram is in a working position, the O-ring is located forward of the ram. When the ram is in a forward position, the O-ring is located in-line with the radial recess of the ram.

Provided is a two-piston hydraulic striking device that has stable operatively. This two-piston hydraulic striking device includes two striking mechanisms for striking one transfer member. Each striking mechanism has a pressure receiving area ratio between the front and rear of a piston thereof set in such a way that the two striking mechanisms have the same cycle time.

The hydraulic rotary-percussive hammer drill includes a fluid injection portion including a fluid feed-in inlet and an annular inner groove fluidly connected to the fluid feed-in inlet; a shank including a fluid injection conduit fluidly connected to the annular inner groove; front and rear main sealing gaskets disposed on either side of the annular inner groove and configured to cooperate with a first shank portion of the shank; a rear backup sealing gasket located at the rear of the rear main sealing gasket and configured to cooperate with a second shank portion of the shank; a leakage passage defined between the shank and the fluid injection portion; pressure drop generation means configured to generate pressure drops in the leakage passage when a leakage flow flows in the leakage passage.

The invention relates to a pneumatically operated drill hammer, comprising a piston and a distributor axially arranged relative to each other in a housing, the piston being arranged to be moved axially between a first position and a second position. The drill hammer further includes a pneumatic drive system, including a drive chamber, a return chamber and a plurality of channels for distribution of drive gas in said drive system. The return chamber is arranged at a lower side of the piston and the drive chamber is arranged at an upper side of the piston, wherein the drive chamber is defined by a variable space enclosed by at least the housing, the piston and the distributor. The drive chamber includes at least one inlet port and at least one exhaust port arranged at a circumference of the drive chamber.

This percussion apparatus includes a striking piston mounted so as to be displaced inside a piston cylinder and arranged to strike a tool; and a guide bearing comprising a guide surface configured to guide the striking piston during the displacements of the striking piston in the piston cylinder. The guide bearing includes a centering device configured to center the striking piston in the piston cylinder, the centering device comprising centering chambers formed in the guide surface and distributed around the striking piston, each centering chamber being fluidly connected to a high pressure fluid supply circuit; and at least one discharge groove formed in the guide surface of the guide bearing and located proximate to at least one of the centering chambers, the at least one discharge groove being fluidly connected to a low pressure circuit.