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.

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 hydraulic percussion device comprising a piston mounted for reciprocal motion within a cylinder to impact a percussion bit and a control valve to control reciprocation of the piston. A valve pilot line is arranged to switch the control valve based on the position of the piston within the cylinder, wherein the valve pilot line is alternately connected, by the reciprocal movement of the piston, to high and low pressure lines (P, T) via an undercut in the piston. The undercut is located at a portion of the piston having a diameter less than the maximum sealing diameter of the 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.

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.

The invention concerns a hydraulic striking tool for application in rock and/or concrete cutting equipment containing a machine housing (100;200) with a cylinder (115;215) with a moveably mounted piston (145;245) which during operation performs a repetitive forward and backward movement relative to the machine housing (100;200) and directly or indirectly strike a rock and/or concrete cutting tool (155;255), and where the piston (145;245) includes a driving part (165;265) which separates a first (120;220) and a second (105;221) driving chamber formed between the piston (145;245) and the machine housing (100;200) and where these driving chambers are arranged to include a pressurized working fluid during operation. The total volume V of the first and second driving chambers is inversely proportional dimensioned to the square of a for the striking tool recommended maximal pressure p, as well as proportional, by a proportionality constant k within the interval 5.3-21.0, to the product of the pistons energy E during the strike against the tool and compression module β of the working fluid.

An apparatus for generating impulse-dynamic process forces includes a pressure chamber, a connecting chamber and a bolt chamber. The pressure chamber includes a plunger arranged to be pushed into the pressure chamber for compression of a hydraulic medium located therein. In the connecting chamber there is displaceably arranged a stepped piston which has a valve body for closing an orifice connecting the pressure chamber to the connecting chamber. In the bolt chamber there is located a displaceable impact bolt which has a first bolt portion and a second bolt portion. The first bolt portion seals an interior space of the bolt chamber that surrounds the second bolt portion. Connected to the bolt chamber there is at least one pressure reservoir containing pressurised pressure medium, which pressure reservoir is in communicating connection via a connection port with the interior space of the bolt chamber.