The hydraulic rotary-percussive hammer drill includes a body; a shank; a striking piston configured to hit the shank; a stop piston configured to position the shank in a predetermined balanced position, the body and the stop piston delimiting a first control chamber permanently connected to a high-pressure fluid feed-in conduit and configured to urge the stop piston forwards, and a second control chamber configured to urge the stop piston forwards. The hydraulic rotary-percussive hammer drill comprises a fluidic communication channel opening into the second control chamber, configured to supply the second control chamber with high-pressure fluid and provided with a calibrated orifice.

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.

A pressure accumulator, rock breaking machine and method of storing pressure energy. The accumulator includes a casing and an elastic membrane arranged inside the casing. The membrane divides an inner space of the casing into two separate pressure spaces. A gas space is prefilled with pressurized gas. On the opposite side of the membrane is a hydraulic space for receiving hydraulic fluid. The membrane is a hat-like element having side walls, a mounting flange at its open end and a closed top end. The mounting flange of the membrane is mounted between the casing and a flange element. The accumulator is without a screen. The flange element is provided with a sealing for sealing a piston.

A variable stroke control system for a hydraulic hammer is disclosed. The variable stroke control system may include an inlet groove formed around a piston associated with the hydraulic hammer and configured to receive pressurized fluid, and an outlet groove formed around the piston associated with the hydraulic hammer and configured to discharge the pressurized fluid. The variable stroke control system may further include a valve in fluid communication with the inlet groove and the outlet groove, and configured to selectively adjust a stroke length of the piston based on a change in pressure differential between the inlet groove and the outlet groove.

This percussion apparatus includes a striking piston, a control distributor arranged to control a reciprocating movement of the striking piston, and a control device arranged to vary the striking stroke of the striking piston. The control device comprises a plurality of control channels, a control channel connected to the control distributor, a control slide movably mounted between a plurality of control positions, and an adjusting slide mounted in a receiving housing delimited by the control slide, the control slide and the adjusting slide delimiting a first adjusting chamber connected to the control channel and a second adjusting chamber connected to a the high-pressure fluid supply circuit. The control slide is movably mounted between a first position in which the first control chamber and the second adjusting chamber are connected and a second position in which the first control chamber and the second adjusting chamber are isolated.

In an impact tool, a vibration absorbing body is fitted on the outside of an outer periphery of an operating body, and the vibration absorbing body is interposed between the operating body and the cover body. The vibration absorbing body includes a tubular main body, and ring bodies attached to be fitted into recessed grooves formed on an inner peripheral surface and an outer peripheral surface of the tubular main body along the circumferential direction and elastically deformed to expand or contract the outside diameter. The ring bodies are maintained in a state where the ring bodies are elastically contracted in a freely expanding or contracting manner.

In an impact tool, a vibration absorbing body is fitted on the outside of an outer periphery of an operating body, and the vibration absorbing body is interposed between the operating body and the cover body. The vibration absorbing body includes a tubular main body, and ring bodies attached to be fitted into recessed grooves formed on an inner peripheral surface and an outer peripheral surface of the tubular main body along the circumferential direction and elastically deformed to expand or contract the outside diameter. The ring bodies are maintained in a state where the ring bodies are elastically contracted in a freely expanding or contracting manner.

A hydraulic accumulator including an energy storage apparatus with a first piston face configured to reversibly compress an energy storage medium and a second piston face forming at least part of an inner surface of a corresponding second fluid chamber reversibly expandable by movement of the second piston face. A third piston face forms at least part of an inner surface of a corresponding third fluid chamber reversibly expandable by the third piston face. The first, second and third piston faces are coupled together.

An accumulator membrane is disclosed. The accumulator membrane may include a generally cylindrical tube having a side wall with a first end a second end. A lip may be located at the first end, and may form a pocket with the side wall. An extension may protrude from the second end at an angle generally perpendicular to the lip and co-axial with the generally cylindrical tube.

The present invention relates to a hydraulic breaker comprising: a back head having a gas chamber provided therein; a cylinder disposed at the lower part of the back head, and having a hydraulic passage and a hydraulic space; a front head disposed at the lower part of the cylinder; a chisel provided inside the front head; a piston provided to reciprocate in the cylinder so as to hit the chisel; and a breaker main body having a plurality of penetration bolts integrally connecting the back head, the cylinder, and the front head, wherein the back head of the breaker main body is provided with a control valve for supplying and blocking hydraulic pressure to/from the hydraulic passage and the hydraulic space.