The invention concerns a rock breaking device comprising a striking cell having at least one actuation chamber, a striking piston, and a hydraulic circuit comprising a hydraulic supply source having a High Pressure circuit and a Low Pressure circuit, and an actuator configured to connect the High Pressure circuit or the Low Pressure circuit to the actuation chamber so as to move the piston in translation in the striking cell in a normal movement area of which the limits are variable depending on the pressure difference between the High Pressure circuit and the Low Pressure circuit, the striking cell comprising depressurizing means configured to control the establishment of hydraulic communication between the High Pressure circuit and the Low Pressure circuit when the striking piston exits a predefined movement area.

Control device of an impact mechanism operable by a pressure media having an element for reversing the axial pressurization of the percussion piston and the return of the medium. In order to achieve a controllability of impact mechanisms by which the energy and the frequency of the moved percussion piston can be adjusted, at least one channel switchable by the reversal as a return line for the medium from the percussion hammer has at least one switchable element for the flow control.

Control device of an impact mechanism operable by a pressure media having an element for reversing the axial pressurization of the percussion piston and the return of the medium. In order to achieve a controllability of impact mechanisms by which the energy and the frequency of the moved percussion piston can be adjusted, at least one channel switchable by the reversal as a return line for the medium from the percussion hammer has at least one switchable element for the flow control.

The present invention relates to a impact body for a hydraulic impact device and, more specifically, to a impact body for a hydraulic impact device which is capable of remarkably reducing production costs by inserting a cylinder liner having a flow path into an inner wall of a body, adjusting an impact interval and an impact strength according to the properties of a material to be crushed by adjusting an impact distance of a piston, minimizing the loss of a fluid in a pipe by forming a cylindrical flow path between the body and the cylinder liner, and remarkably improving performance by employing a circular valve to shorten the flow path whereby reduction of pressure is minimized.

The present invention relates to a impact body for a hydraulic impact device and, more specifically, to a impact body for a hydraulic impact device which is capable of remarkably reducing production costs by inserting a cylinder liner having a flow path into an inner wall of a body, adjusting an impact interval and an impact strength according to the properties of a material to be crushed by adjusting an impact distance of a piston, minimizing the loss of a fluid in a pipe by forming a cylindrical flow path between the body and the cylinder liner, and remarkably improving performance by employing a circular valve to shorten the flow path whereby reduction of pressure is minimized.

A switching method includes starting up a percussion device in acting on a control device arranged to vary the striking stroke of the striking piston between a short striking stroke and a long striking stroke. The percussion device is forced to operate on a short striking stroke for a predetermined period of time from the starting up of the device, and in acting on the control device so as to allow the percussion device to operate on a long striking stroke, after the expiry of the predetermined period of time.

A switching method includes starting up a percussion device in acting on a control device arranged to vary the striking stroke of the striking piston between a short striking stroke and a long striking stroke. The percussion device is forced to operate on a short striking stroke for a predetermined period of time from the starting up of the device, and in acting on the control device so as to allow the percussion device to operate on a long striking stroke, after the expiry of the predetermined period of time.

A breaking device includes a frame, an impact device having a pressure chamber with a rear pressure chamber and a front pressure chamber. The breaking device further includes a first low pressure port at the rear pressure chamber, a first low pressure channel and a first low pressure accumulator connected to the first low pressure channel. The breaking device further includes a second low pressure port at the rear pressure chamber substantially opposite to the first low pressure port, second low pressure channel and a second low pressure accumulator connected to the second low pressure channel. The first low pressure accumulator and the second low pressure accumulator are arranged at the outer circumference of the frame of the breaking device at different positions in the axial direction of the breaking device.

A breaking device includes a frame, an impact device having a pressure chamber with a rear pressure chamber and a front pressure chamber. The breaking device further includes a first low pressure port at the rear pressure chamber, a first low pressure channel and a first low pressure accumulator connected to the first low pressure channel. The breaking device further includes a second low pressure port at the rear pressure chamber substantially opposite to the first low pressure port, second low pressure channel and a second low pressure accumulator connected to the second low pressure channel. The first low pressure accumulator and the second low pressure accumulator are arranged at the outer circumference of the frame of the breaking device at different positions in the axial direction of the breaking device.

A device in a hydraulic rock drilling machine (1) has a distribution valve (7, 7, 7) for controlling hydraulic flow to different parts of the rock drilling machine. The distribution valve has a valve body (8, 8, 8) which moves to and from in an axial direction inside a valve chamber (33). The valve chamber is limited in axial direction by two valve end walls (10, 11; 10, 11; 10, 11). One of the valve end walls is movable in an axial direction against an abutment (12, 12) to define an end position for the valve body, and a pressing device (13, 13, 13) is provided for pressing at least one of the valve end walls against the abutment. A rock drilling machine includes the device.