Rock drilling machine and drill RIG comprising such a rock drilling machine

Abstract

Rock drilling machine (10) comprising a hydraulic percussion unit (11) including a percussion piston (12) for providing percussive impulses to a shank adapter (13) of the rock drilling machine (10) in a forward direction (Dfwd), the shank adapter (13) being configured to be connected to a drill string (6) during operation. A hydraulic damper unit (14) is arranged for damping the recoil movement of the shank adapter (13) in the backward direction (Drev), and a hydraulic extractor unit (16) is arranged for actuating the shank adapter (13) in the backward direction (Drev). The rock drilling machine comprises an inlet coupling (Cp) for connection to a pressure source (P) of pressurised hydraulic fluid and an outlet coupling (CT) for connection to a tank (T) for non-pressurised hydraulic fluid. Further, the inlet coupling (Cr) is connectable to both the hydraulic damper unit (14) and the hydraulic extractor unit (16). The disclosure also relates to a drill rig comprising such a rock drilling machine. (FIG. 4)

Description

[0001] ROCK DRILLING MACHINE AND DRILL RIG COMPRISING SUCH A ROCK DRILLING MACHINE

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to a rock drilling machine and to a drill rig comprising such a rock drilling machine.

[0004] BACKGROUND

[0005] In the technical field of rock drilling, a hydraulic rock drilling machine is arranged on a feeder at an outer end of a boom that extends from a drill rig. Hoses to provide the hydraulic rock drilling machine with hydraulic fluid, water, air, and lubrication etc. are arranged in reels or other types of arrangements that offer flexibility, both for the movement of the hydraulic rock drilling machine with respect to the feeder, but also for the positioning of the feeder with respect to the boom.

[0006] These arrangements of hoses are often both bulky and exposed to harsh conditions. In many cases the hoses may get tangled up against a rock surface resulting in hose ruptures. Further, a drill rig normally comprises at least two separate feeders extending from separate booms, each feeder carrying a hydraulic rock drilling machine and the associated hose arrangements. A common problem is that these separate hose arrangements may hinder each other, which may result in operational problems or hose ruptures resulting in lengthy down-times of the drill rig.

[0007] Further, each hydraulic function of a rock drilling machine needs to be fed with a separate hydraulic supply. Conventionally, such hydraulic functions include a rotation unit for rotating the drill string, a percussion unit for providing a hammering function on the drill string driven by the rock drilling machine, a damper unit for damping the percussive action of the percussion unit, and an extractor unit, which is activated when the drill string is to be retracted inside the drill hole.

[0008] It would be advantageous to find a solution of a rock drilling machine and a drill rig overcoming, or at least alleviating, at least one or some of the drawbacks of the prior art.

[0009] SUMMARY

[0010] It is an object of the present disclosure to provide a rock drilling machine and a drill rig with an efficient use of provided hydraulic fluid. 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.

[0011] According to a first aspect, the disclosure relates to a rock drilling machine that is operable in a forward direction and a backward direction, opposite to the forward direction.

[0012] The rock drilling machine comprises a hydraulic percussion unit with a percussion piston for providing percussive impulses to a shank adapter of the rock drilling machine in the forward direction, the shank adapter being configured to be connected to a drill string during operation.

[0013] It also comprises a hydraulic damper unit with a damper piston for damping the movement of the percussion piston when the rock drilling machine is driven in the forward direction, and a hydraulic extractor unit with an extractor piston actuating the shank adapter to move in the backward direction.

[0014] The rock drilling machine further comprises an inlet coupling for connection via a first supply conduit to a pressure source of pressurised hydraulic fluid and an outlet coupling for connection via a return conduit to a tank for non-pressurised hydraulic fluid.

[0015] The inlet coupling is connectable to both the hydraulic damper unit and the hydraulic extractor unit, on at the time, depending on if the rock drilling machine is driven in the forward or backward direction.

[0016] An advantage of this arrangement is that the extractor unit and the damper may be fed via the same conduit, thereby eliminating the need of at least one conduit. Also, only one return conduit is needed, thereby further keeping the number of conduits to a minimum.

[0017] In embodiments of the disclosure the hydraulic damper unit and the hydraulic extractor unit are connected in series. Namely, the hydraulic damper unit may be arranged to allow passive passage of hydraulic fluid when the rock drilling machine is driven in the backward direction and the hydraulic extractor unit may be arranged to allow passive passage of hydraulic fluid when the rock drilling machine is driven in the forward direction.

[0018] In embodiments of the disclosure the damper unit comprises a damper chamber arranged to be provided with a hydraulic fluid via a first inlet opening which is connectable to the inlet coupling, wherein a first outlet opening is arranged for connecting the damper chamber to the outlet coupling. Further, the extractor unit comprises an extractor chamber arranged to be provided with a hydraulic fluid via a second inlet opening which is also connectable to the inlet coupling, wherein a second outlet opening is arranged for connecting the extractor chamber to the outlet coupling.

[0019] Also, the damper chamber and the extractor chamber are arranged in series, either in that the first outlet opening of the damper chamber is connected via a first auxiliary conduit to the second inlet opening of the extractor chamber, or in that the second outlet opening of the extractor chamber is connected via a second auxiliary conduit to the first inlet opening of the damper chamber.

[0020] In embodiments of the disclosure, in the damper chamber, the damper piston comprises a first axial surface arranged to face the damper chamber such that a first hydraulic pressure in the damper chamber acts on the first axial surface to push the damper piston in the forward direction, the damper piston being arranged to govern a first restriction passage connecting the damper chamber to the first outlet opening, the first restriction passage being open when the damper piston is in a passive forward position with respect to the forward direction and restricted when the damper piston is in a backward position with respect to the forward direction.

[0021] Similarly, in the extractor chamber, the extractor piston comprises a second axial surface arranged to face the extractor chamber such that a second hydraulic pressure in the extractor chamber acts on the second axial surface to push the extractor piston in the backward direction, the extractor piston being arranged to govern a second restriction passage connecting the extractor chamber to the second outlet opening, the second restriction passage being open when the extractor piston is in a passive backward position with respect to the forward direction and restricted when the extractor piston is in a forward position with respect to the forward direction.

[0022] Hence, the hydraulic arrangement of the disclosure is self-regulating, such that the operation direction of the rock drilling will govern in which chamber the pressure will provide the wanted effect of damping or extracting, respectively.

[0023] Specifically, when the rock drilling machine is driven in the forward direction, the shank adapter acts on the damper piston in the backward direction to the backward position in which the first restriction passage is restricted while the second hydraulic pressure acts on the second axial surface to push the extractor piston to its passive backward position in which the second restriction passage is open, i.e. unrestricted. On the contrary, when the rock drilling machine is driven in the backward direction, the shank adapter acts on the extractor piston in the forward direction to its forward position in which the second restriction passage is restricted while the first hydraulic pressure acts on the first axial surface to push the damper piston to its passive forward position in which the first restriction passage is open, i.e. unrestricted.

[0024] According to a second aspect, the disclosure relates to a drill rig comprising one or more rock drilling machines as described. The drill rig comprises a hydraulic pressure source of pressurised hydraulic fluid and a hydraulic tank for non-pressurised hydraulic fluid, wherein a supply conduit, preferably in the form of a first hose, is arranged to connect the pressure source to the inlet coupling of the rock drilling machine, wherein a return conduit, preferably in the form of a second hose, is arranged to connect the outlet coupling of the rock drilling machine to the tank.

[0025] Other embodiments of the disclosure according to the different aspects thereof and advantages of these embodiments will be apparent from the detailed description and the appended drawings.

[0026] BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Below, specific embodiments of the disclosure will be described with reference to the appended drawings, of which:

[0028] Fig. 1 is a very schematic view of a rock drilling machine according to possible embodiment of the disclosure,

[0029] Fig. 2 is a cut view of a rock drilling machine according to a first embodiment of the disclosure when driven in a forward direction,

[0030] Fig. 3 is a cut view of a rock drilling machine according to a second embodiment of the disclosure when driven in a forward direction,

[0031] Fig. 4 is a close view of the rock drilling machine according to the first embodiment of the disclosure when driven in the forward direction,

[0032] Fig. 5 is a close view of the rock drilling machine according to the first embodiment of the disclosure when driven in a backward direction,

[0033] Fig. 6 is a cut detailed view of the rock drilling machine according to the first embodiment of the disclosure when driven in the forward direction, Fig. 7 is a cut detailed view of the rock drilling machine according to the first embodiment of the disclosure when driven in a backward direction, and

[0034] Fig. 8 is a very schematic view of a drill rig carrying three rock drilling machines on separate booms.

[0035] DETAILED DESCRIPTION

[0036] In Fig. 8 a drill rig 1 with three booms 5A-5C with individual rock drilling machines 10A-10C arranged on separate feeders 7A-7C is schematically shown. The feeders 7A-7C are arranged on feed beam holders 4A-4C arranged at the outer end of the respective booms 5A-5C. In Fig. 8 it is illustrated how the three rock drilling machines 10A-10C operate by drilling individual drill strings 6A-6C into a rock face 9. As the rock drilling machines 10A- 10C operate the drill strings’ 6A-6C way into the rock face 9 they advance in a forward direction DfWd from a back end 2A-2C of the feeder 7A-7C to a front end 8A-8C thereof.

[0037] The drill rig 1 comprises a hydraulic arrangement comprising at least one pressure source P and a tank T. The hydraulic arrangement is arranged to provide pressurised hydraulic fluid to advance the rock drilling machines 10A-10C along the corresponding feeders 7A- 7C and to feed the different consumers of the rock drilling machines 10A-10C. Separate supply conduits HP, are arranged to connect the pressure source P to an inlet coupling on the rock drilling machines 10A-10C and separate return conduits HTare arranged to connect an outlet coupling of the rock drilling machines 10A-10C to the tank T.

[0038] One or both of the supply conduit HPand the return conduit HTmay be provided as a hose, whereof at least the supply conduit HPis arranged to withstand high pressures. As an alternative, one or both of the supply conduit HPand the return conduit HTmay be provided as an internal conduit inside the booms 5A-5C.

[0039] This disclosure is mainly aimed at the hydraulic arrangement of the individual rock drilling machines 10A-10C.

[0040] In Fig. 1 , a hydraulic rock drilling machine 10 according to an exemplary embodiment of the disclosure is illustrated in a schematic manner.

[0041] The rock drilling machine 10 comprises a hydraulic percussion unit 11 including a percussion piston 12 for providing percussive impulses to a shank adapter 13 in a forward direction Dtwd, to the left in the drawings. The shank adapter 13 is arranged to be connected to a drill string 6 at its outer end (left in the drawing) during operation. The forward direction Dtwd corresponds to the direction in which the drill string is driven when drilling is performed into for example a rock.

[0042] A hydraulic damper unit 14 including a damper piston 15 is arranged for damping the recoil movement of the shank adapter 13 when the rock drilling machine 10 is driven in the forward direction Dtwd-

[0043] A hydraulic extractor unit 16 including an extractor piston 17 is arranged for providing a backward movement to the shank adapter 13 when the rock drilling machine 10 is driven in a backward direction Drevopposite to the forward direction DfWd. The backward direction Drevhence corresponds to the direction in which the drill string is driven when drill string is being pulled backwards, for example out from a drilled hole.

[0044] In addition to what is shown in Fig. 1 , the rock drilling machine 10 may include or be complemented by a rotation device (not shown) for rotating a drill bit at the outer end of the drill string 6. This disclosure is independent of the function of such a rotation device, and it is therefore not described in detail in this application.

[0045] In Fig. 2 the rock drilling machine 10 according to a first embodiment of the disclosure is shown in a cut view when driven in the forward direction Dtwd- When the rock drilling machine 10 is driven in the forward direction Dtwd an advancing force FfWd, acting in the forward direction DfWd, is applied to the rock drilling machine 10 to push rock drilling machine 10 forward along the feeder 7 on which it is arranged.

[0046] The advancing force FfWd acting on the rock drilling machine 10 pushes the drill string 6 into the drill hole by simultaneous activation of the percussion piston 12, which intermittently abuts the shank adapter 13 to provide percussive impulses thereto. Further, a recoil action of the shank adapter 13 is restricted by the damper piston 15, which is also arranged to abut the shank adapter 13. A first hydraulic pressure in a damper chamber 20 will act on the damper piston 15 in the forward direction DfWd, such that the damper piston 15 will find itself in a floating equilibrium position between the force from the shank adapter 13 on one side and the first hydraulic pressure in the damper chamber 20 on the opposite side.

[0047] When the drilling machine 10 is driven in the forward direction Dtwd, the extractor piston 17 is not exposed to any pressure from the shank adapter 13 and will be pushed by a first pressure acting in a damper chamber 23 to an unstressed backward end position, to the right in the drawing. An inlet coupling Cp is provided on the rock drilling machine 10 for connection to a supply conduit HP, which is connected to a pressure source P of pressurised hydraulic fluid. An outlet coupling CT is provided on the rock drilling machine 10 for connection to a return conduit HTleading to a tank T for non-pressurised hydraulic fluid.

[0048] The pressure source P and the tank T are typically arranged on a drill rig 1 as described above with reference to Fig. 8.

[0049] The inlet coupling Cp is eligibly connected to the hydraulic damper unit 14 or the hydraulic extractor unit 16 depending on if the rock drilling machine 10 is driven in the forward direction DfWd or the backward direction Drev.

[0050] Specifically, the hydraulic damper unit 14 and the hydraulic extractor unit 16 may be connected in series, the hydraulic damper unit 14 being arranged to allow passive passage of hydraulic fluid when the rock drilling machine 10 is driven in the backward direction Drevand the hydraulic extractor unit 16 being arranged to allow passive passage of hydraulic fluid when the rock drilling machine 10 is driven in the forward direction DfWd-

[0051] The damper chamber 20 of the damper unit 14 is arranged to be provided with a hydraulic fluid via a first inlet opening 21 connected to the inlet coupling Cp, and a first outlet opening 22 is arranged for connecting the damper chamber 20 to the outlet coupling CT.

[0052] Similarly, the extractor chamber 23 of the extractor unit 16 is arranged to be provided with a hydraulic fluid via a second inlet opening 24 connected to the inlet coupling Cp, a second outlet opening 25 being arranged for connecting the extractor chamber 23 to the outlet coupling CT.

[0053] As an alternative to connecting the extractor unit 16 and the damper unit 14 in series, a valve arrangement (not shown) could be arranged on the rock drilling machine 10 to govern the incoming hydraulic fluid from the pressure source P to either the extractor chamber 23 or the damper chamber 20, depending on in which direction the rock drilling machine 10 is driven.

[0054] When the damper chamber 20 and the extractor chamber 23 are arranged in series, the first or second outlet opening 22 or 25 of either the damper chamber 20 or the extractor chamber 23, respectively, may be connected via a first or second auxiliary conduit Hxi or HX2, respectively, to the second or first inlet opening 24 or 21 , respectively, of the other of the extractor chamber 23 and the damper chamber 20. The first or second auxiliary conduit Hxi or HX2 may be provided as an internal channel inside the housing of the rock drilling machine 10 or as an external conduit, preferably in the form of a pressure withstanding hose.

[0055] In the first embodiment shown in Fig. 2, the inlet coupling Cp is connected to the first inlet opening 21 leading into the damper chamber 20, and further via the first outlet opening 22 and the first auxiliary conduit HXito the second inlet opening 24 to the extractor chamber 23. The second outlet opening 25 leads from the extractor chamber 23 to the outlet coupling CT, for further conveyance in the return conduit HTto the tank T.

[0056] For illustrational reasons, the fluid lines in the drawings are represented as solid lines when carrying pressurised hydraulic fluid and as broken lines when carrying low pressure hydraulic fluid.

[0057] In the first embodiment shown in Fig. 2, when the rock drilling machine 10 is driven in the forward direction Dtwd, the damper chamber 20 is active such that a pressure drop corresponding to the force with which the damper piston 15 acts on the shank adapter 13 occurs from the damper chamber 20 to the first outlet opening 22. Thereby, the hydraulic fluid that leaves the damper chamber 20 will be of low pressure for the rest of its passage to the tank T, i.e., via the first auxiliary conduit HXi, the second inlet opening 24, the extractor chamber 23, the second outlet opening 25, and the return conduit HT. The pressure drop occurs from the extractor chamber 23 to the second outlet opening 25.

[0058] The pressure drop of the hydraulic fluid in the damper chamber 20 will correspond to the force with which the damper piston 15 acts on the shank adapter 13, which to a great extent equals the force Ftwd acting on the rock drilling machine 10 in the forward direction Dtwd- The first pressure in the damper chamber 20 will however vary greatly during operation in dependence of the percussive action provided by the percussion piston 12 on the shank adapter 13.

[0059] In a second embodiment, shown in Fig. 3, the rock drilling machine 10 is also illustrated when driven in the forward direction Dtwd-

[0060] However, in contrary to the first embodiment, the inlet coupling Cp of the second embodiment is connected to the second inlet opening 24 leading into the extractor chamber 23. Subsequently the hydraulic fluid is led via the second outlet opening 25 and a second auxiliary conduit HX2to the first inlet opening 21 into the damper chamber 20. The first outlet opening 22 from the chamber 20 leads to the outlet coupling CT, for further conveyance to the tank T via the return conduit HT. Hence, in this embodiment, with the occurring circumstances where the rock drilling machine 10 is driven in the forward direction Dtwd, high pressure hydraulic fluid will pass through the passive extractor chamber 23 and continue without pressure loss through the second auxiliary conduit HX2 and the first inlet opening 21 to the damper chamber 20 in which the pressure drop will occur such that the hydraulic fluid will leave the damper chamber 20 at low pressure through the first outlet opening 22 and the return conduit HTto the tank T.

[0061] It should be noted that the pressure of the provided hydraulic fluid may differ depending on if the rock drilling machine 10 is driven in the forward direction Dtwd or the backward direction Drev. Typically, a higher pressure is demanded when driven in the forward direction DfWd when the drill string 6 is pushed into the rock 9 under the influence of the percussive motion generated by the percussion unit 11 . The drill rig 1 may comprise a control unit (not shown) to control the hydraulic pressure provided by the pressure source P depending on a current pressure demand. This is conventional to a person skilled in the art and is therefore not described in detail here.

[0062] However, in contrast to conventional arrangements, the flow of the hydraulic fluid and its action on the extractor piston 15 and the extractor piston 17 will be self-regulatory as will become clear from the below description.

[0063] In Figs. 4 and 5, the first embodiment the rock drilling machine 10 is shown in a closer view when driven in the forward direction Dtwd and the backward direction Drev, respectively.

[0064] Hence, Fig. 4 represents the circumstances illustrated in Fig. 2, where the rock drilling machine 10 of the first embodiment is driven in the forward direction Dtwd and Fig. 5 represents the same rock drilling machine 10 when driven in the backward direction Drev.

[0065] When the rock drilling machine 10 of the first embodiment is driven in the backward direction Drevas illustrated in Fig. 5, the damper chamber 20 is passive such that there will be no pressure drop in the passage through it.

[0066] Namely, the force Frevacting in the backward direction Drevwhen the rock drilling machine 10 is driven backwards to pull the drill string 6 out from the drill hole results in that the extractor piston 17 will act on the shank adapter 13 in the backward direction Drev. A second hydraulic pressure, acting in the extractor chamber 23 will act on the extractor piston 17 in the backward direction Drev, such that the extractor piston 17 will find itself in a floating equilibrium position between the force from the second hydraulic pressure in the extractor chamber 23 on one side and the shank adapter 13 on the opposite side. Hence, under these circumstances, there will be a pressure drop of the hydraulic fluid in the extractor chamber 23 corresponding to the force with which the extractor piston 17 acts on the shank adapter 13, which basically equals the force Frevacting on the rock drilling machine 10. The pressure drop occurs from the extractor chamber 23 to the second outlet opening 25.

[0067] Hence, the hydraulic fluid will have a high pressure through the damper chamber 20 and the first auxiliary conduit HXi. It will continue at high pressure through the second inlet opening 24 and into the extractor chamber 23, in which the pressure drops. For the rest of its passage to the tank T, i.e., through the second outlet opening 25 and the return conduit HT, the hydraulic fluid will be of low pressure.

[0068] In Figs. 6 and 7, details of the first embodiment of the rock drilling machine 10 are shown in cut views when the rock drilling machine 10 is driven in the forward direction DfWd and the backward direction Drev, respectively.

[0069] As is visible in these views, the damper piston 15 comprises a first axial surface 26 arranged to face the damper chamber 20 such that the first hydraulic pressure acting in the damper chamber 20 will act on this first axial surface 26 to push the damper piston 17 in the forward direction Dfwd.

[0070] The damper piston 15 is arranged to govern the size of a first restriction passage 27 leading from the damper chamber 20 to the first outlet opening 22. Specifically, the first restriction passage 27 is restricted when the damper piston 15 is positioned in a backward position with respect to the forward direction DfWd as illustrated in Fig. 6, and open when the damper piston 15 is positioned in a passive forward position with respect to the forward direction Dtwd, as illustrated in Fig. 7.

[0071] Likewise, in the extractor chamber 23, the extractor piston 17 comprises a second axial surface 28 arranged to face the extractor chamber 23 such that a second hydraulic pressure acting in the extractor chamber 23 will act on the second axial surface 28 to push the extractor chamber 23 in the backward direction Drev.

[0072] The extractor piston 17 is arranged to govern a second restriction passage 29 from extractor chamber 23 and the second outlet opening 25, the second restriction passage 29 being open, i.e. unrestricted, when the extractor piston 17 is positioned in a passive backward position with respect to the forward direction Dfwd, as illustrated in Fig. 6, and restricted when the extractor piston 17 is positioned in a forward position, as illustrated in Fig. 7. Hence, when the rock drilling machine 10 is driven in the forward direction Dtwd, the shank adapter 13 will act on the damper piston 15 towards its backward position in which the first restriction passage 27 is restricted while, under the influence of the second hydraulic pressure on the second axial surface 28, the extractor piston 17 will assume its backward position, in which the second restriction passage 29 is open, i.e. unrestricted.

[0073] Correspondingly, when the rock drilling machine 10 is driven in the backward direction Drev, the shank adapter 13 will act on the extractor piston 17 towards its forward position in which the second restriction passage 29 is restricted, while under the influence of the first hydraulic pressure on the first axial surface 26, the damper piston 15 will assume its forward position, in which the first restriction passage 27 is open, i.e. unrestricted.

[0074] It should be noted that the restricted positions are floating positions in which the size of the restriction may vary.

[0075] For example, when the damper piston 15 is in its backward position, as illustrated in Fig. 6, the first restriction passage 27 is restricted and the damper piston 15 is in a floating self- regulatory position, where the shank adapter 13 will push the damper piston 15 in the backward direction Drev, and the first pressure will act on the damper piston 15 in the opposite forward direction Dtwd, such that an equilibrium will be attained. When the damper piston 15 is moved in the backward direction Drevfrom this position the first pressure will increase at the same time as the first restriction passage 27 becomes further restricted, wherein the increased pressure will ultimately push the damper piston 15 harder in the forward direction DfWd to thereby increase the passage through the first restriction passage 27 (decrease the restriction) and relieve the first pressure.

[0076] Likewise, when the extractor piston 17 is in its forward position, as illustrated in Fig. 7, the second restriction passage 29 is restricted and the extractor piston 17 is in a floating self- regulatory position, where the shank adapter 13 will push the extractor piston 17 in the forward direction DfWd, and the second pressure will act on the extractor piston 17 in the opposite backward direction Drev, such that an equilibrium will be attained. Typically, when the extractor piston 17 is moved in the forward direction Dtwd, the second pressure will increase at the same time as the second restriction passage 29 becomes further restricted, wherein the increased pressure will push the extractor piston 17 harder in backward direction Drevto increase the passage through the restriction passage 29 (decrease the restriction) and thereby relieve the second pressure. Above, the disclosure has been described with reference to specific embodiments. The disclosure is however not limited to these embodiments. It is obvious to a person skilled in the art that other embodiments are possible within the scope of the following claims.

Claims

CLAIMS1 . A rock drilling machine (10) that is operable in a forward direction (Dtwd) and a backward direction (Drev) opposite to the forward direction (Dtwd), the rock drilling machine (10) further comprising: a hydraulic percussion unit (11 ) including a percussion piston (12) for providing percussive impulses to a shank adapter (13) of the rock drilling machine (10) in the forward direction (DfWd), the shank adapter (13) being configured to be connected to a drill string (6) during operation, a hydraulic damper unit (14) including a damper piston (15) for damping the movement of the percussion piston (12) in the forward direction (Dtwd), and a hydraulic extractor unit (16) including an extractor piston (17) for actuating the shank adapter (13) to move in the backward direction (Drev), wherein the rock drilling machine further comprises an inlet coupling (Cp) for connection via a first supply conduit (HP) to a pressure source (P) of pressurised hydraulic fluid and an outlet coupling (CT) for connection via a first return conduit (HT) to a tank (T) for non-pressurised hydraulic fluid, and wherein the inlet coupling (Cp) is connectable to both the hydraulic damper unit (14) and the hydraulic extractor unit (16).

2. The rock drilling machine according to claim 1 , wherein the hydraulic damper unit (14) and the hydraulic extractor unit (16) are connected in series, the hydraulic damper unit (14) being arranged to allow passive passage of hydraulic fluid when the rock drilling machine (10) is driven in the backward direction (Drev) and the hydraulic extractor unit (16) being arranged to allow passive passage of hydraulic fluid when the rock drilling machine (10) is driven in the forward direction (DfWd).

3. The rock drilling machine according to claim 1 or 2, wherein the damper unit (14) comprises a damper chamber (20) arranged to be provided with a hydraulic fluid via a first inlet opening (21 ) connectable to the inlet coupling (Cp), and wherein a first outlet opening(22) is arranged for connecting the damper chamber (20) to the outlet coupling (CT), the extractor unit (16) comprises an extractor chamber (23) arranged to be provided with a hydraulic fluid via a second inlet opening (24) connectable to the inlet coupling (Cp), and wherein a second outlet opening (25) is arranged for connecting the extractor chamber(23) to the outlet coupling (CT), and wherein the damper chamber (20) and the extractor chamber (23) are arranged in series, either in that the first outlet opening (22) of the damper chamber (20) is connected via a first auxiliary conduit (Hxi) to the second inletopening (24) of the extractor chamber (23), or in that the second outlet opening (25) of the extractor chamber (23) is connected via a second auxiliary conduit (Hx?) to the first inlet opening (21 ) of the damper chamber (20).

4. The rock drilling machine according to claim 3, wherein in the damper chamber (20), the damper piston (15) comprises a first axial surface (26) arranged to face the damper chamber (20) such that a first hydraulic pressure in the damper chamber (20) acts on the first axial surface (26) to push the damper piston (15) in the forward direction (Dfwd), the damper piston (15) being arranged to govern a first restriction passage (27) connecting the damper chamber (20) to the first outlet opening(22), the first restriction passage (27) being open when the damper piston (15) is in a passive forward position with respect to the forward direction (Dfwd) and restricted when the damper piston (15) is in a backward position with respect to the forward direction (Dfwd), and wherein in the extractor chamber (23), the extractor piston (17) comprises a second axial surface (28) arranged to face the extractor chamber (23) such that a second hydraulic pressure in the extractor chamber (23) acts on the second axial surface (28) to push the extractor piston (17) in the backward direction (Drev), the extractor piston (17) being arranged to govern a second restriction passage (29) connecting the extractor chamber(23) to the second outlet opening (25), the second restriction passage (29) being open when the extractor piston (17) is in a passive backward position with respect to the forward direction (Dfwd) and restricted when the extractor piston (17) is in a forward position with respect to the forward direction (Dfwd).

5. The rock drilling machine according to claim 4, wherein when the rock drilling machine (10) is driven in the forward direction (Dfwd), the shank adapter (13) acts on the damper piston (15) in the backward direction (Drev) to the backward position in which the first restriction passage (27) is restricted while the second hydraulic pressure acts on the second axial surface (28) to push the extractor piston (17) to its passive backward position in which the second restriction passage (29) is open, and wherein when the rock drilling machine (10) is driven in the backward direction (Drev), the shank adapter (13) acts on the extractor piston (17) in the forward direction (Dfwd) to its forward position in which the second restriction passage (29) is restricted while the first hydraulic pressure acts on the first axial surface (26) to push the damper piston (15) to its passive forward position in which the first restriction passage (27) is open.

6. A drill rig (1 ) comprising one or more rock drilling machine(s) (10; 10A, 10B, 10C) according to any one of the preceding claims, the drill rig (1) further comprising a hydraulic pressure source (P) of pressurised hydraulic fluid and a hydraulic tank (T) for nonpressurised hydraulic fluid, wherein a supply conduit (HP), preferably in the form of a first hose, is arranged to connect the pressure source (P) to the inlet coupling (Cp), and wherein a return conduit (HT), preferably in the form of a second hose, is arranged to connect the outlet coupling (CT) to the tank (T).

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