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.

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.

A hydraulic hammer is provided. The hydraulic hammer includes a fluid inlet configured to receive a pressurized fluid for running the hydraulic hammer and a fluid outlet for discharging hydraulic fluid from the hydraulic hammer. A bypass passage fluidly connects the fluid inlet and the fluid outlet, the bypass passage has a bypass inlet fluidly connected to the fluid inlet and a bypass outlet fluidly connected to the fluid outlet. An automatic shut-off valve is disposed in the bypass passage between the bypass inlet and the bypass outlet and is configured to open or close the bypass passage. The automatic shut-off valve is configured to open the bypass passage under pressure of the pressurized fluid on continuous running of the hydraulic hammer for a set time to stop the hammer.

A hydraulic hammering device includes a piston front chamber and a piston rear chamber defined between an outer circumferential surface of the piston and an inner circumferential surface of the cylinder and disposed separately from each other at front and rear, respectively, in an axial direction. A switching-valve mechanism drives the piston by switching at least one of the piston front chamber and the piston rear chamber into communication with at least one of a high pressure circuit and a low pressure circuit. An acceleration piston is disposed behind the piston and is configured to come into contact with the piston during a retreat stroke thereof to urge the piston forward, in which a timing where the acceleration piston itself starts to come in contact with the piston is set to be earlier than a timing where the piston is braked by the switching-valve mechanism.

A hydraulic hammering device includes a piston front chamber and a piston rear chamber defined between an outer circumferential surface of the piston and an inner circumferential surface of the cylinder and disposed separately from each other at front and rear, respectively, in an axial direction. A switching-valve mechanism drives the piston by switching at least one of the piston front chamber and the piston rear chamber into communication with at least one of a high pressure circuit and a low pressure circuit. An acceleration piston is disposed behind the piston and is configured to come into contact with the piston during a retreat stroke thereof to urge the piston forward, in which a timing where the acceleration piston itself starts to come in contact with the piston is set to be earlier than a timing where the piston is braked by the switching-valve mechanism.

This hydraulic percussion apparatus, includes a guide body; a striking piston which is slidably mounted inside the guide body; a sealing device which is mounted in an annular retaining groove provided on the guide body so as to produce a sealing between a first fluid passage and a second fluid passage. The sealing device comprises includes an inner sealing ring including an inner sealing portion provided with a sealing lip sealingly cooperating with the striking piston, an annular protection portion which is internally delimited by a converging protection surface converging towards the sealing lip, an annular groove which is disposed between the sealing lip and the converging protection surface, and a balancing channel comprising first and second ends opening respectively into the annular groove and into an outer surface of the annular protection portion.

This hydraulic percussion apparatus, includes a guide body; a striking piston which is slidably mounted inside the guide body; a sealing device which is mounted in an annular retaining groove provided on the guide body so as to produce a sealing between a first fluid passage and a second fluid passage. The sealing device comprises includes an inner sealing ring including an inner sealing portion provided with a sealing lip sealingly cooperating with the striking piston, an annular protection portion which is internally delimited by a converging protection surface converging towards the sealing lip, an annular groove which is disposed between the sealing lip and the converging protection surface, and a balancing channel comprising first and second ends opening respectively into the annular groove and into an outer surface of the annular protection portion.

A piston guiding element, rock drilling machine and method for supporting a front end portion of a percussion piston of a rock drilling machine. The piston guiding element includes a braking recess at its rear end. The element further includes at least one bearing sleeve, which is provided with two axially successive slide bearing sections. Hydraulic fluid is conveyed between the slide bearing sections via a feed system.

A piston guiding element, rock drilling machine and method for supporting a front end portion of a percussion piston of a rock drilling machine. The piston guiding element includes a braking recess at its rear end. The element further includes at least one bearing sleeve, which is provided with two axially successive slide bearing sections. Hydraulic fluid is conveyed between the slide bearing sections via a feed system.

Disclosed is a fluid driven pulsating, hammering tool operational when pressurized fluid is pumped into the tool's upper sub, having a poppet valve which can seal the upper end of a slidable outer valve assembly when closed; an inner valve assembly slidable within the outer valve assembly; wherein the inner and outer valve assemblies remain in selective fluid communication with the poppet valve even when the poppet valve is closed, wherein interruption of said fluid communication occurs from movement of the inner and/or outer valve assemblies to particular positions along their sliding paths; and further including a lower valve which is preferably a Tesla valve having channels which are also in fluid communication with the poppet valve.