An apparatus including an accumulator and a drive mechanism. The accumulator includes 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

A hydraulic hammer for impact fracturing a work object includes a hammer shell having a cylinder body disposed between a front head and a rear head. A piston reciprocally movable within the cylinder body abut a work tool and can extend and retract the work tool from the hammer shell. To dampen momentum and impact forces, an accumulator head is attached to the back head and can accommodate hydraulic and dampening fluids in separate first and second sub-chambers. The dampening sub-chamber may directly fluidly communicate with an internal dampening fluid reservoir in the back head.

A percussion apparatus including a pressure regulating device comprising a regulating cylinder; a connecting channel opening into the regulating cylinder; a pressure regulating slide mounted movable in translation within the regulating cylinder and delimiting, with the regulating cylinder, a connecting passage having a passage section which varies according to the regulating position occupied by the pressure regulating slide; a biasing element configured to exert a prestress on the pressure regulating slide; and a prestress setting device configured to set a prestress exerted by the biasing element on the pressure regulating slide.

A pressure indicator for a hydraulic hammer is provided. The pressure indicator includes a sleeve member configured to couple to an opening defined in a wall housing of an accumulator of the hydraulic hammer. The pressure indicator further includes a plunger slidably disposed within the sleeve member and movable between a first position and a second position with respect to the sleeve member. The plunger includes a first end disposed outside the wall housing of the accumulator. The plunger further includes a flange coupled to a second end. The pressure indicator further includes an elastic member inserted over the plunger and disposed between the wall housing of the accumulator and the flange. A position of the first end of the plunger with reference to an outer end of the sleeve member provides a visual indication of the pressure of the gas within the accumulator.

An accumulator assembly includes a vessel having an upper portion and a lower portion. The accumulator assembly includes a flexible membrane extending between the upper portion and the lower portion. The membrane may divide the vessel into a first interior chamber and a second interior chamber. The accumulator assembly includes a receptacle located proximate the vessel. The receptacle may be in fluid communication with the second interior chamber. The accumulator assembly includes a plunger located at least partially within the receptacle.

A hydraulic hammer assembly is disclosed. The hydraulic hammer assembly includes a piston and an accumulator membrane disposed external and coaxial to the piston The hydraulic hammer assembly includes a sleeve disposed coaxially between the piston and the accumulator membrane. The sleeve defines a first set of holes in an outer surface thereof to receive hydraulic fluid. The sleeve defines a second set of holes in an inner surface thereof and located distant from the first set of holes along a longitudinal axis of the sleeve. The sleeve defines a plurality of passages within a wall, and extending along the longitudinal axis. Each of the plurality of passages includes a porous medium to increase surface area of each of the plurality of passages. The increased surface area of each of the plurality of passages increases a rate of dissipation of heat from the wall of the sleeve.

A power tool includes an air spring cylinder. A piston is movably positioned within the cylinder. A head valve assembly of the power tool includes a flapper valve configured to seal the air spring cylinder from an air accumulator when the flapper valve is in a non-firing position.

The invention provides a valveless hydraulic impact mechanism for connection to a tool for processing rock or concrete or both, wherein the position for the opening of the drainage channel is arranged along the cylinder bore so as to be opened and closed by a portion of the reciprocating strike piston, the position for the opening of the connection channel leading to the first drive chamber is arranged along the cylinder bore so as to be opened and closed by a portion of the reciprocating strike piston and the position for the opening of the connection channel leading to the second drive chamber is arranged in the first or second cylinder bore so as to be opened and closed by a portion of the reciprocating accumulator piston such that, with the aid of the strike piston during its motion in the first cylinder bore and the accumulator piston in the first cylinder bore or, if present, the second cylinder bore, at least the second drive chamber acquires periodically alternating pressure for the maintenance of the reciprocating piston motion, wherein the reciprocating strike and accumulator pistons hold the second drive chamber closed for the supply or drainage of driving medium present in the second drive chamber along a distance between the opening of the drainage channel in association with a first turning point of the strike piston and the opening of the connection channel in association with a second turning point of the strike piston, wherein the motion of the strike piston along the distance between the opening of the drainage channel in association with the first turning point of the strike piston and the opening of the connection channel in association with the second turning point of the strike piston takes place during compression of the volume of the accumulator compartment, wherein the magnitude of the volume of the accumulator compartment is adapted to obtain a slow change in pressure in the second drive chamber along the distance between the channel openings and wherein the strike piston and accumulator piston are solely in fluid communication such that the strike piston and accumulator piston do not make direct contact during operation of the mechanism.

A hydraulic hammer includes: a cylinder having a first cylinder end and a second cylinder end opposite the first cylinder end; a piston disposed within the cylinder, the piston having a first piston end, the piston being reciprocatingly movable with respect to the cylinder along an axial direction; a valve body disposed on the first cylinder end so as to define a valve body cavity; and a seal carrier sealingly arranged between the first piston end and the first cylinder end and being reciprocatingly movable with respect to the cylinder along the axial direction. The piston is reciprocatingly movable with respect to the seal carrier along the axial direction.