Lubrication system includes a drive fluid valve member and a detune valve member. The drive fluid valve member is movable from a first to a second position in response to drive fluid pressure to reduce the volume of a variable volume lubricant charge chamber. The detune valve member is movable from a first to a second position in response to lubricant pressure within the lubricant charge chamber, and is adapted to permit fluid communication between inlet and bypass fluid passages in its the first position and to disengage the fluid connection in its second position.

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.

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.

A hydraulic hammer including a housing, a piston arranged for reciprocating movement within the housing, a hydraulic circuit within the housing. The hydraulic circuit is configured for connection to a source of pressurized fluid. The hydraulic circuit includes an inlet passage configured to provide a hydraulic fluid to the piston, an outlet passage configured to provide a return flow path for the hydraulic fluid from the piston a bypass passage selectively connecting the inlet passage to the outlet passage and a thermostatic valve assembly configured to connect the inlet passage to the piston when the temperature of the hydraulic fluid is below a threshold temperature and connect the inlet passage to the bypass passage when the temperature of the hydraulic fluid is above the threshold temperature.

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.

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.

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.

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 hammering device that uses a scheme in which a front chamber is switched into communication with a low-pressure circuit when a piston advances, wherein occurrences of galling to the piston at a sliding contact portion with a front-chamber liner is reduced. The front chamber has the front-chamber liner fitted to an inner surface of a cylinder. A hydraulic chamber space communicating with the front chamber and filled with hydraulic oil is formed as a cushion chamber on the inner peripheral surface of a rear portion of the front-chamber liner. The cushion chamber has a second drain circuit (from first end face grooves to slits to second end face grooves, which is provided separately from a drain circuit that guides the hydraulic fluid passing through a liner bearing of the front-chamber liner to the low-pressure circuit.