A hammer including a housing and a piston arranged for reciprocating movement within the housing is disclosed. The hammer further includes a head assembled on the housing and defining a chamber for holding a pressurized gas and a wall configured to abut the housing and defining a gas discharge passage extending between the chamber and the housing. A plug is positioned in the gas discharge passage and configured to move or deform under pressure of the pressurized gas in the chamber.

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 method for manufacturing of a wear resistant component including the steps of providing a form defining at least a portion of the shape of the component; providing a powder mixture comprising 30-70 vol % of a powder of tungsten carbide and 70-30 vol % of a powder of a nickel based alloy, wherein the nickel based alloy consists of, in weight %: C: 0-1.0; Cr: 0-14.0; Si: 2.5-4.5; B: 1.25-3.0; Fe: 1.0-4.5; the balance being Ni and unavoidable impurities, and wherein the powder of tungsten carbide has a particle size of 105-250 m and the powder of the nickel based alloy has a maximum particle size of 32 m; filling at least a portion of the form with the powder mixture; and subjecting the form to Hot Isostatic Pressing at a predetermined temperature, a predetermined isostatic pressure and a for a predetermined time so that the particles of the nickel-based alloy bond metallurgically to each other.

An impact system for a hydraulic hammer is disclosed. The impact system may include a piston, a sleeve disposed co-axial with the piston, and an accumulator membrane disposed external to the sleeve. A first seal may be located at an end of the sleeve, and configured to connect the sleeve to the piston. The accumulator membrane may have an extension configured to engage a recess in the sleeve.

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 is disclosed having a piston and an accumulator membrane disposed external and co-axial to the piston. Additionally, a sleeve is disposed between the piston and accumulator membrane, wherein the sleeve has a plurality of radial passages formed therein that fluidly connect the accumulator membrane with the piston.

Provided is a hydraulic hammering device having improved hammering efficiency and of low cost. A piston has a valve switching groove between large-diameter sections thereof. A cylinder has three control ports at positions corresponding to the valve switching groove. A switching valve mechanism has a valve presser for always pressing a valve in one direction and also has a valve controller for moving, when supplying pressurized oil, the valve in the opposite direction against the pressing force of the valve presser. A valve control port communicates with the valve controller so as to supply the pressurized oil to the valve controller and is separated from a piston front chamber and a piston rear chamber. Only either a piston retraction control port or a piston advance control port communicates with the valve control port depending on advance or retraction of the valve switching groove.

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.

An arrangement and method for heating an impact device of a rock treating machine (Rtm) in low-temperature operating conditions is provided. The arrangement includes a warm-up mode (WM) for feeding pre-heated hydraulic fluid through a feed channel to a hydraulic circuit of the impact device. One or more hydraulic accumulators are provided in the hydraulic circuit. The feed channel is provided with a control element for limiting the feeding of the pre-heated hydraulic fluid during the warm-up mode. The control element limits the feeding of the pre-heated hydraulic fluid in the feed channel so that separating elements of the pressure accumulators do not move.