Emergency displacement of hydraulically actuated equipment

Abstract

A system (1) comprising a hydraulic circuit comprising one or more hydraulic actuators (6) arranged to displace a hydraulically actuated equipment (2) attached to a boom (3), and at least one sequence valve (5). The one or more hydraulic actuators (6) is configured to displace the attached equipment (2) at a first hydraulic oil operating pressure during normal operation of the attached equipment (2), and at a second hydraulic oil pressure higher than the first hydraulic oil operating pressure during emergency displacement operation of the attached equipment. The sequence valve (22) is activated at the second hydraulic oil operating pressure to activate the emergency displacement operation of the attached equipment (2).

Description

TECHNICAL FIELD The present disclosure relates in general to rock drilling, and to equipment which may be used in, for example, mining industry. More specifically, the disclosure relates to a system for emergency displacement of at least one hydraulically actuated equipment attached to a respective boom of a rock drilling rig. Further, methods for emergency displacement of at least one hydraulically actuated equipment attached to a respective boom of a rock drilling rig comprising one or more drilling booms is provided. The disclosure also relates to a rock drilling rig, as well as a computer program and a computer-readable medium that implement methods herein. BACKGROUND A rock drilling rig carries one or more drilling machines on respective booms. Each rock drilling machine is movable on a feed beam connected to a respective boom, and the rock drilling machine may be moved along the feed beam by means of a hydraulic feed device. Furthermore, each rock drilling machine may be provided with a hydraulic percussion device. Consequently, the rock drilling comprises a plurality of hydraulic circuits and associated hydraulic valves. To reduce the complexity of the hydraulic circuits, distributed hydraulics may be used for a number of functions. Distributed hydraulics are enabled through electronic control of hydraulic valves that form part of locally arranged hydraulic circuits. Two functions that may be realized through such electronic control of hydraulic valves are the aforementioned hydraulic feed device and the hydraulic percussion device. The distributed hydraulics reduces the number of hydraulic hoses necessary to maneuver or activate these functions required for the drilling operation. When electronically controlled hydraulic valves are employed, one or more cables will also have to be routed along-side the boom to allow the valves to be controlled. Electric cables and hydraulic hoses in mining environment may break if damaged by falling rocks, or they may break due to mechanical wear and tear. If one or more of these cables breaks, hydraulic valve function is lost, and the connected equipment cannot be moved or controlled. When the equipment is in an awkward position at the time of such cable break it may not be possible to replace the faulty cable, and therefore it may not be possible to move the affected functions into a position allowing the necessary movement of the drill rig or repairs to be performed. Thus, there is a need for a solution to enable activating vital functions to allow equipment to be controlled and moved in the event of a broken cable, loss of communication, loss of valve function, or other faults setting normal operation aside. SUMMARY It is an object of the present disclosure to achieve an in at least some aspects improved system for control of hydraulically actuated equipment of a rock drilling rig. In particular, it is an object to provide such a system and method for emergency displacement of hydraulically actuated equipment that is attached to a boom of a rock drilling rig in the event of a broken cable, loss of communication, loss of valve function, or other faults setting normal operation aside. The above and further objects are solved by the subject matter of the appended independent claims. Further advantageous embodiments can be found in the dependent claims. According to a first aspect, a system for emergency displacement of at least one hydraulically actuated equipment attached to a respective boom of a rock drilling rig is provided. The rock drilling rig comprises control circuitry for controlling the respective boom and the attached equipment. The system comprises a hydraulic circuit comprising one or more hydraulic actuators arranged to displace the attached equipment, and a sequence valve. The one or more hydraulic actuators is configured to displace the attached equipment at a first hydraulic oil operating pressure during normal operation of the attached equipment, and at a second hydraulic oil pressure higher than the first hydraulic oil operating pressure during emergency displacement operation of the attached equipment. The sequence valve is activated at the second hydraulic oil operating pressure to activate the emergency displacement operation of the attached equipment. The system enables activation of vital functions to allow equipment to be controlled and moved in the event of a broken cable, loss of communication, loss of valve function, or other faults setting normal operation aside. In some examples, the hydraulic circuit may comprise two or more hydraulic actuators arranged to enable displacement of the attached equipment. At least one of the one or more hydraulic actuators may be arranged to displace the attached equipment by providing a retracting movement. Typically, there is a need of enabling retraction of equipment from a working position to a non-working position if normal working processes are out of order. In some examples, at least one of the one or more hydraulic actuator may be arranged to provide a percussion force for enabling displacement of the attached equipment. If equipment is stopped during a working process, there is a risk of equipment being stuck, and by providing a percussion function equipment may come loose in a safe and efficient way. In embodiments, hydraulic oil return flow from the hydraulic circuit may flow via one or more check valves when the sequence valve is activated. In embodiments, the system for emergency displacement may further comprise a restriction arranged to pass occurring surplus hydraulic oil to a drain when the sequence valve is deactivated. Thereby the pressure in the system will be enabled to easily be set to normal operation pressure if desired. In some examples, the system for emergency displacement may further comprise at least one pump arranged to increase the oil pressure in the hydraulic circuit to the second hydraulic oil working pressure whereby the sequence valve is activated. The system for emergency displacement may further comprise two or more pumps, each being arranged to increase the oil pressure in the hydraulic circuit to the second hydraulic oil working pressure whereby the sequence valve is activated. According to another aspect, a method for emergency displacement of at least one hydraulically actuated equipment attached to a respective boom of a rock drilling rig is provided. The rock drilling rig comprises one or more drilling booms and control circuitry for controlling the respective boom and the attached equipment. A hydraulic circuit comprises one or more hydraulic actuators arranged to displace the attached equipment. The hydraulic circuit is arranged to work at a first hydraulic oil working pressure during normal operation, and at a second hydraulic oil working pressure being higher than the first hydraulic oil working pressure during emergency displacement operation. The method comprises indicating a failure, increasing the oil pressure to the second hydraulic oil working pressure, activating a sequence valve arranged to be activated at the second hydraulic oil working pressure, feeding oil to the hydraulic circuit via the activated sequence valve, performing an emergency displacement of the attached equipment by activating at least one of the one or more hydraulic actuators. In some examples, emergency displacement of the attached equipment may be enabled by a percussion function. Emergency displacement of the attached equipment may also be performed as a retracting movement. In further examples, emergency displacement of the attached equipment may be performed as a retracting movement and a percussion function applied substantially simultaneously. In some examples, methods herein may further comprise returning hydraulic oil return flow from the hydraulic circuit via one or more check valves when the sequence valve is activated. In some examples, methods herein may further comprise lowering the pressure from the second hydraulic oil working pressure to the first hydraulic oil working pressure, deactivating the sequence valve and passing occurring surplus hydraulic oil to a drain via a restriction. According to yet another aspect, a rock drilling rig comprising a system for emergency displacement according to embodiments herein is provided. According to yet another aspect, a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out methods disclosed herein. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a block diagram showing an exemplified system for emergency displacement according to embodiments herein. Fig. 2 is an overview showing a rock drilling rig in use in a tunnel. Fig. 3 is a principal outline showing examples of hydraulic actuators. Fig. 4 is one example of a hydraulic circuit for a rock drilling rig with an emergency displacement system according to embodiments herein implemented. Fig. 5 is a flowchart showing methods herein. DETAILED DESCRIPTION The present disclosure will now be described in more detail with reference to the accompanying drawings, in which exemplary embodiments are shown. However, the disclosure is not to be considered as limited to the exemplified embodiments. An exemplified system 1 for emergency displacement of hydraulically actuated equipment 2 will now be described more in detail with reference to Fig. 1. A rock drilling rig 4 may comprise one boom 3, or a plurality of booms 3. The booms 3 typically carry equipment 2 attached to a respective boom 3. Thus, hydraulically actuated equipment 2 is attached to a boom 3 of a rock drilling rig 4. Such attached equipment 2 may typically be a rock drilling machine, but other types of hydraulically activated equipment may be used as well. The rock drilling rig 4 comprises control circuitry 7 for controlling the hydraulically actuated equipment 2 and the boom 3, respectively. The system 1 comprises a hydraulic circuit comprising one or more hydraulic actuators 6 arranged to displace the attached equipment 2. The hydraulic actuators 6 are configured to displace the attached equipment 2 in desired directions and movements. One single actuator 6 may be employed, or a plurality of actuators. The actuators 6 are arranged to operate at a first hydraulic oil operating pressure during normal operation of the attached equipment 2. The system 1 for emergency displacement further comprises a sequence valve 5 which is used to activate the emergency displacement system 1. It may be noted that although one single sequence valve is shown in the exemplifying drawings, two or more sequence valves 5 may be employed in alternative embodiments. For example, a further sequence valve 5 may be used to ensure redundancy when it comes to activation of the system 1, or the sequence valves may be arranged to activate different hydraulic actuators 6 of the hydraulic circuit or may be arranged to be activated at different operating pressure. Thereby, a flexible system for emergency displacement is provided. In the examples shown in the attached drawings, one single sequence valve 5 is employed. A typical emergency displacement is to retract the attached equipment 2. A possible situation when the system for emergency displacement is activated is if a cable break, or communication break, occurs during a drilling operation. The drill and the drill bit may thus stop located inside a drilling hole, and one way of displacing the drill is to retract it from the drill hole. Another way of affecting the attached equipment 2, like the drill with the drill bit, is to apply a percussion force on the attached equipment. In that case, at least one hydraulic actuator 6 is arranged to provide the percussion force for enabling displacement of the attached equipment 2. The actuators 6 are arranged to be able to work at a second hydraulic oil pressure when the emergency displacement system 1 is activated. The second hydraulic oil pressure is higher than the first hydraulic oil operating pressure and is used during emergency displacement operation of the attached equipment. The sequence valve 5 is activated at the second hydraulic oil operating pressure in order to activate the emergency displacement operation of the attached equipment 2. Fig. 2 is an overview showing a rock drilling rig 4 in use in a tunnel 9. The rock drilling rig 4 is an underground drilling rig and is shown in a position for drilling holes in a drilling surface during tunnel excavation. The rock drilling rig shown comprises a drilling unit 11 arranged together with a drilling boom 3. A drill 12 is shown in a drilling position inside a drill hole. The rock drilling rig 4 comprises a carrier 10 arranged to move the rig. The rock drilling rig 4 further comprises a system 1 for emergency displacement according to any of the embodiments disclosed herein. The rock drilling rig 4 is arranged to communicate with a control system. The control system may be located remote or local. The control system typically comprises one or more control unit, which controls various functions of the rock drilling rig 4 and the drilling unit 11, e.g., by suitable control of various actuators, motors, pumps etc. Rock drilling rigs 4 may comprise more than one control unit, where each control unit, respectively, can be arranged to be responsible for functions of the rock drilling rig 4. Fig. 3 is a principal outline showing examples of hydraulic actuators 6 to be used for movement of attached equipment, like a drill provided with a drill bit. The actuators 6 shown are hydraulic cylinders arranged to provide movement back and forth. During normal operation, the drill and the drill bit are moved forward towards a rock wall when a drilling operation is about to start. Once drilling is completed the drill is retracted from the drill hole and the drilling procedure continues with the next hole to be drilled. When the system for emergency displacement is activated, a desired movement is typically to retract the drill from a drillhole. In a rock drill provided with telescopic drill feed, two hydraulic cylinders may be employed. In that case, the two cylinders 6 work in parallel to realize a telescopic drill feed function. When in use, the system 1 for emergency displacement of hydraulically actuated equipment 2 used in rock drilling works as follows. The hydraulically actuated equipment 2 is moved by hydraulic actuators 6 in a hydraulic circuit in which typically electronically controlled hydraulic valves are employed to control movements of the equipment 2. The hydraulic actuators 6 are configured to displace the equipment 2 at a first hydraulic oil operating pressure during normal operation. Electric cables routed along-side of a rock drilling boom 3 in order to control the hydraulic valves may break due to wear, or due to accidently falling parts of rock, causing the hydraulic valve function to be lost. The equipment 2 actuated by the hydraulic actuators 6 controlled via the thus non-operable hydraulic valve therefore cannot be moved or controlled, and a failure is indicated. The system 1 comprises a sequence valve 5 arranged to be activated at a second hydraulic oil working pressure being higher than the first normal operation working pressure. To activate the system 1 for emergency displacement, the oil pressure in the hydraulic circuit is increased. By increasing the pressure to the second hydraulic oil working pressure, the sequence valve 5 is activated. Thereafter, oil to the hydraulic circuit is fed via the activated sequence valve 5. An emergency displacement of the attached equipment can then be performed by activating one or more of the hydraulic actuators 6. The hydraulic actuator 6 may be arranged to displace the attached equipment 2 by providing a retracting movement. The hydraulic actuator 6 can be configured to displace the attached equipment in a first direction and / or in a second, reverse direction. During emergency operation normally a retracting movement is desirable, however, the system may as well be arranged to provide both a retracting movement and an advancing movement. The system 1 may comprises two or more hydraulic actuators 6 arranged to enable displacement of the attached equipment 2. Fig. 4 is one example of a hydraulic circuit for a rock drilling rig with a system 1 for emergency displacement according to embodiments herein implemented; a rock drilling rig utilizing distributed hydraulics for a number of functions and at least one hydraulically actuated equipment 2 attached to a respective boom 3 of a rock drilling rig 4. Distributed hydraulics are used in order to reduce the number of hydraulic hoses required along the boom to maneuver or activate functions applied to equipment attached at the end of the boom. Two of these functions are drill feed and percussion of the rock drilling machine used. Hydraulically actuated equipment attached to the boom is moved by hydraulic actuators, in the figure shown as two hydraulic cylinders, C1 and C2. The hydraulic actuators are configured to displace the attached equipment 2 at a first hydraulic oil operating pressure during normal operation of the attached equipment, and at a second hydraulic oil pressure higher than the first hydraulic oil operating pressure during emergency displacement operation of the attached equipment. The drill feed function on a standard feed is realized by a single hydraulic cylinder C1. In a telescopic drill feed two hydraulic cylinders, C1 and C2, work in parallel to realize the telescopic drill feed function. The respective hydraulic cylinder C1 and C2 is controlled via electronically controlled hydraulic solenoid valves SV1 and SV2. Further, a rock drill percussion function is present. The percussion function is in the figure marked with an arrow, and the function is controlled via another electronically controlled hydraulic solenoid valve SV3. The hydraulic circuit is controlled by use of two electronic control units, ECLI1 and ECLI2. It may be noted that control units may be locally or remotely positioned. The control unit ECLI2 controls the electronically controlled hydraulic solenoid valves SV1, SV2 and SV3 by control signals sent via electric cables or wires W1 - W7, e.g., W3-W7. During normal operation, the hydraulic circuit works as follows. The hydraulic oil working pressure P in the hydraulic circuit is set to pressure P1 by use of one or more oil pressure pumps 8. The pump or pumps may be driven by an electric motor, or any other means like for example a diesel motor. Pressure for the pumps is according to the figure controlled by the control unit ECLI1 via the wire W1, and power and communication signals to the control unit ECLI2 is provided from ECU1 via the wire W2. At the pressure P1 hydraulic sequence valves SQ1 and SQ2 are inactivated and closed. The hydraulic cylinders C1 and C2 are typically used to retract or advance a drill provided with a drill bit during a drilling operation. Control signals sent from the control unit ECLI1 via the wires W3 and W4 controls the valve SV1 which operates back or forth movement of the cylinder C1, and control signals sent via the wires W5 and W6 control the valve SV2 which operates back or forth movement of the cylinder C2. The percussion function is controlled by a control signal sent from the control unit ECLI2 via the wire W7 to the valve SV3 which in turn controls the percussion function. A number of possible errors may occur in such circuit, all resulting in that the equipment cannot be operated and is stopped in a present position. If contact or output from ECU1 to the wire W2 is faulty with total loss of power and / or communication, ECU1 will stop working and no signals will be sent out to operate the system. If the wire W2 breaks, or if contact or input from the wire W2 to the control unit ECLI2 is faulty the result is also a total loss of power and / or communication from ECLI1. Further, if contact or output from the control unit ECLI2 to any of the wires W4, which controls a retracting movement of hydraulic cylinder C1, W5, which controls a retracting movement of hydraulic cylinder C2, or W7 which controls the percussion function is faulty, there will be a loss of signals to the designated valves SV1, SV2 and SV3 and the attached equipment cannot be operated. If the wire W4 breaks with loss of signal to the valve SV1 the retracting function is lost for the hydraulic cylinder C1. If the wire W5 breaks with loss of signal to the valve SV2 the retracting function is lost for the hydraulic cylinder C2, and if the wire W7 breaks with loss of signal to the valve SV3 the percussion function is lost. Any of these faults may result in that rock drilling is stopped during operation and that the equipment used, like a drill string, a drill steel, and / or a drill bit, may get stuck in a drilling hole. In order to come loose from the rock, the percussion function may be needed. Once loose from the drill hole, the drill may need to be retracted from the drill hole. The herein disclosed system and method for emergency displacement provides a solution for those situations. A sequence valve 5 is activated at said second hydraulic oil operating pressure to activate said emergency displacement operation of the attached equipment. The system for emergency displacement of hydraulically actuated equipment is integrated in the circuit shown in figure 4 and works as follows. Two sequence valves are present, SQ1 and SQ2. The sequence valves SQ1 and SQ2 are arranged to be activated at a second hydraulic oil working pressure P3 being higher than the first normal operation working pressure P1. If a failure is indicated and there is a need of activating the system for emergency displacement, the pressure in the hydraulic circuit is increased from P1 to P3. This is performed by use of a pump, or several pumps. By increasing the pressure to the second hydraulic oil working pressure, the sequence valves SQ1 and SQ2 are activated. Once the sequence valve SQ1 is activated, the hydraulic oil will flow via two check valves CV1. Flow of hydraulic oil via the first check valve CV1 will apply pressure to the first hydraulic cylinder C1, and flow of hydraulic oil the other check valve CV1 will apply pressure to the second hydraulic cylinder C2. Activating the sequence valve SQ1 thus provide a bypass function overriding any of the control electronics controlled by ECLI2. The system for emergency displacement thus provides retracting movement of both hydraulic cylinders C1 and C2 as long as the pressure is set to pressure P3 and the sequence valve SQ1 is activated. Typically, during emergency displacement mode, or bypass mode, pressure is applied to the respective cylinders C1 and C2 such that a retracting movement of the drill steel is performed. Activating the sequence valve SQ1 also allow flow of hydraulic oil via the check valve CV3 and pressure will be applied to the percussion function. According to the exemplified embodiment in the figure, oil will flow through all check valves CV1 (two valves in figure 4) and CV3 more or less simultaneously and the retracting movement performed by cylinder C1, the retracting movement performed by cylinder C2 and the percussion force will all be applied on the stopped equipment. Although the present arrangement in the circuit shown in figure 4 apply oil flow through all check valves more or less at the same time, other embodiments where functions are applied individually or in sequence may as well be possible within the scope of disclosures herein. It is further to be noted that applying pressure P3 in the hydraulic circuit also activates the sequence valve SQ2 which together with two check valves CV2 is used for the return flow of the hydraulic oil during emergency displacement operation. Thus, once the emergency displacement operation is started by increasing the pressure to P3, the hydraulic oil will flow through the sequence valve SQ1 via the check valves CV1 and CV3, to the hydraulic cylinders C1 and C2 and the percussion function, and with return flow path through the check valves CV2 and the sequence valve SQ2. To turn off the emergency operation, the pump, or pumps may simply be turned off in order to drop the hydraulic oil pressure in the system. Once the pressure is dropped below P3, the sequence valves SQ1 and SQ2 will be deactivated and closed and the cylinders C1 and C2 and the percussion function will stop. The system may thereafter be restarted by applying pressure P1 by help of the pump or pumps. Alternatively, to turn off the pump, the pressure in the system may be set to the normal operation pressure, P1, and normal operation will be enabled. Once the pressure in the system is lowered below P3 and the sequence valve SQ2 closes, any surplus hydraulic oil will be passed via a restriction R1 arranged to drain and the system is enabled to return to normal hydraulic oil pressure P1. Fig. 5 is a flow chart showing methods 100 for emergency displacement of at least one hydraulically actuated equipment disclosed herein. The hydraulically actuated equipment is attached to a respective boom of a rock drilling rig comprising one or more drilling booms. At normal operation, the hydraulic system works at a first hydraulic oil work pressure. Methods herein comprises indicating a failure in step 101, increasing the oil pressure in step 102 to a second hydraulic oil working pressure higher that the first hydraulic oil working pressure, and in step 103 activating sequence valve 5 arranged to be activated at the second hydraulic oil working pressure. Methods herein further comprises in step 104 feeding oil to the hydraulic circuit via the activated sequence valve 5. In step 105 emergency displacement of the attached equipment is performed by activating at least one of the one or more hydraulic actuators 6. In some examples, the emergency displacement of the attached equipment is performed as a retracting movement and / or as a percussion function, e.g., by performing emergency displacement of the attached equipment retracting movement and a percussion function applied substantially simultaneously. In some examples, the emergency displacement comprises returning hydraulic oil return flow from the hydraulic circuit via one or more check valves when the sequence valve 5 is activated. The method for emergency displacement may further comprise the steps of lowering the pressure from the second hydraulic oil working pressure to the first hydraulic oil working pressure, deactivating the sequence valve 5, and passing occurring surplus hydraulic oil to a drain via a restriction. It will be appreciated that the foregoing description and the accompanying drawings represent non-limiting examples of the system and methods taught herein. As such, the apparatus and techniques taught herein are not limited by the foregoing description and accompanying drawings. Instead, the embodiments herein are limited 5 only by the following claims and their legal equivalents.

Claims

1. A system (1) for emergency displacement of at least one hydraulically actuated equipment (2) attached to a respective boom (3) of a rock drilling rig (4),the rock drilling rig (4) comprising control circuitry for controlling the respective boom (3) and the attached equipment (2), wherein the system (1) comprises a hydraulic circuit comprising one or more hydraulic actuators (6) arranged to displace the attached equipment (2), and at least one sequence valve (5),wherein said one or more hydraulic actuators (6) is configured to displace the attached equipment (2) at a first hydraulic oil operating pressure during normal operation of the attached equipment, and at a second hydraulic oil pressure higher than the first hydraulic oil operating pressure during emergency displacement operation of the attached equipment,wherein the sequence valve (5) is activated at said second hydraulic oil operating pressure to activate said emergency displacement operation of the attached equipment.

2. System (1) for emergency displacement according to the preceding claim, wherein at least one of the one or more hydraulic actuators (6) is configured to displace the attached equipment (2) by applying a retracting movement.

3. System (1) for emergency displacement according to any of the preceding claims, wherein the hydraulic circuit comprises two or more hydraulic actuators (6) arranged to enable displacement of said attached equipment.

4. System (1) for emergency displacement according to any of the preceding claims, wherein at least one of the one or more hydraulic actuators (6) is arranged to provide a percussion force for enabling displacement of said attached equipment.

5. System (1) for emergency displacement according to any of the preceding claims, wherein hydraulic oil return flow from the hydraulic circuit flows via one or more check valves when the sequence valve (5) is activated.

6. System (1) for emergency displacement according to any of the preceding claims, further comprising a restriction arranged to pass occurring surplus hydraulic oil to a drain when the sequence valve (5) is deactivated.

7. System (1) for emergency displacement according to any of the preceding claims, further comprising at least one pump arranged to increase the oil pressure in the hydraulic circuit to the second hydraulic oil working pressure whereby the sequence valve (5) is activated.

8. System (1) for emergency displacement according to any of the preceding claims, further comprising two or more pumps (8), each being arranged to increase the oil pressure in the hydraulic circuit to the second hydraulic oil working pressure whereby the sequence valve (5) is activated.

9. Method for emergency displacement of at least one hydraulically actuated equipment (2) attached to a respective boom (3) of a rock drilling rig (4) comprising one or more drilling booms (3) and control circuitry for controlling the respective boom (3) and the attached equipment (2), a hydraulic circuit comprising one or more hydraulic actuators (6) arranged to displace said attached equipment, and the hydraulic circuit being arranged to work at a first hydraulic oil working pressure during normal operation, and at a second hydraulic oil working pressure being higher than the first hydraulic oil working pressure during emergency displacement operation,the method comprising:- indicating (101) a failure,- increasing (102) the oil pressure to the second hydraulic oil working pressure,- activating (103) a sequence valve (5) arranged to be activated at said second hydraulic oil working pressure,- feeding oil (104) to the hydraulic circuit via the activated sequence valve (5),- performing (105) an emergency displacement of the attached equipment by activating at least one of said one or more hydraulic actuators (6).

10. Method according to the preceding claim, wherein emergency displacement of the attached equipment is performed as a retracting movement.

11. Method according to claim 9 or 10, wherein emergency displacement of the attached equipment (2) is performed as a percussion function.

12. Method according to any of claim 9 -11, wherein emergency displacement of the attached equipment (2) is performed as a retracting movement and a percussion function applied substantially simultaneously.

13. Method according to any of claim 9-12, further comprising returning hydraulic oil return flow from the hydraulic circuit via one or more check valves when the sequence valve (5) is activated.

14. Method for emergency displacement according to any of claims 9-13, further comprising- lowering the pressure from the second hydraulic oil working pressure to the first hydraulic oil working pressure,- deactivating the sequence valve (5),- passing occurring surplus hydraulic oil to a drain via a restriction.

15. Rock drilling rig (4) comprising a system (1) for emergency displacement according to any of claims 1-8.1716. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to any of claims 9-14.

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