EP4589114A1

EP4589114A1 - Protective device, rock drilling unit, and method

Info

Publication number: EP4589114A1
Application number: EP24152600.3A
Authority: EP
Inventors: Aleksi MÄKILOUKO
Original assignee: Sandvik Mining and Construction Oy
Current assignee: Sandvik Mining and Construction Oy
Priority date: 2024-01-18
Filing date: 2024-01-18
Publication date: 2025-07-23
Also published as: WO2025153252A1

Abstract

A protective device, rock drilling unit and method. The protective device (9) comprises a protective casing (10) mountable around a drilling tool (8). The protective casing comprises at least openable and closable rigid chain (11) provided with parallel chain members (15a, 15b). The chain members comprise grip elements (16) which can interlock with each other and form a closed structure. By disengaging the grip elements, the protective casing can be opened. The opening and closing is executed in response to movements of a rock drilling machine (6) in a drilling direction (A) and in a reverse direction (B).

Description

Background of the invention

The invention relates to a protective device arrangeable around a drilling tool of a rock drilling rig.
The invention further relates to a rock drilling unit provided with a protective device, and a method for providing protection in a rock drilling unit.
The field of the invention is defined more specifically in the preambles of the independent claims.
In mines, construction sites and at other work areas different type of rock drilling rigs are used for drilling holes for different purposes. The rock drilling rigs are provided with one or more booms and rock drilling units are arranged at distal ends of the booms for drilling the drill holes. During drilling rotating drilling tools are provided with impact pulses. There exist a need to use protective devices around the drilling tools. This is the case particularly in surface drilling. However, the present protective devices have shown to contain some disadvantages regarding their complicated, expensive and clumsy structure.

Brief description of the invention

An object of the invention is to provide a novel and improved protective device and method for a rock drilling unit. The invention further relates to a novel and improved rock drilling unit implementing the protective device.
The protective device according to the invention is characterized by the characterizing features of the first independent apparatus claim.
The rock drilling unit according to the invention is characterized by the characterizing features of the second independent apparatus claim.
The method according to the invention is characterized by the characterizing features of the independent method claim.
An idea of the disclosed solution is that a protective device comprises a protective casing which is mountable to surround a drilling tool connected to a rock drilling machine. The protective casing comprises a rigid chain provided with two adjacent and parallel chain members which are both provided with grip elements facing towards each other. The grip elements are configured to interlock the adjacent chain members together and are configured to allow the chain members to disengage from each other in response to movement of the rock drilling machine in a drilling direction and in a reverse direction.
In other words, the rigid chain forms alone, or in combination with additional components, a protective structure around the drilling tool. Thus, the protective casing limits a tool space around the drilling tool. The protective casing based on the rigid chain configuration is capable of adjusting length of the tool space in accordance with movements of the rock drilling machine during drilling process.
An advantage of the disclosed solution is that the structure of the protective casing forms a mechanical and reliable structure around the rotating drilling tool. Then safety risk of catching on to rotating machine parts can be effectively avoided. The protective casing can be arranged close to the drilling tool whereby the protective casing takes only little space, may be light in weight and does not form visibility barriers. The disclosed solution can be implemented in a versatile manner in different kind of rock drilling units, and it can also be retrofitted to the existing drilling units.
The grip elements not only close and open the protective casing but also keep the structure relatively rigid since they prevent the chain members from separating when the rock drilling machine is fed forwards in the drilling direction and compressive longitudinal force is subjected to the rigid chain. Thus, the rigid chain is relatively rigid in lateral direction i.e., in x-direction. The rigid chain is also relatively rigid in a direction perpendicular to the lateral x-direction i.e., in y-direction. In a movement direction of the rock drilling machine i.e., in z-direction length of a closed part of the rigid chain automatically adjusts in accordance with feed movements of the rock drilling machine.
According to an embodiment, each of the grip elements comprise a protrusion and a notch both having round shapes. The round shapes allow smooth turning movements between opposing grip elements when the basic chain elements move in relation to each other. The opposing grip elements are configured to interlock with each other so that the protrusions match with the opposing notches. The interlocking opens when the parallel chain members are directed away from each other so that the relative parallel orientation no longer exists.
The rigid chain can also be called as an interlocking chain, or as a zip chain.
The rigid chain does not comprise any dedicated actuator for interlocking and disengaging the chain members. Instead, the movement of the rock drilling machine on z-axis in a drilling direction causes the rigid chain to disengage i.e., the drilling direction is a chain disengagement direction, and movement on the z-axis in a reverse direction causes the grip elements to interlock with each other i.e., the reverse direction is a chain interlocking direction. Thus, it can be considered that the rigid chain is actuated by means of a feed device arranged to move the rock drilling machine on the feed beam.
According to an embodiment, the rigid chain comprises a first chain member and a second chain member both having a plurality of chain links on their opposing sides and wherein subsequent chain links are connected to each other by means of coupling elements allowing turnable connections between subsequent chain links. The grip elements are separate pieces in relation to the chain links which are mounted on outer surfaces of the first and second chain members. In other words, the separate grip elements are mounted on chain links belonging to the basic chain structure. An advantage of this embodiment is that it is possible to use commercially available chain structures and to provide them with the separate grip elements to form suitable chain members for the rigid chain. Further, the basic chain structure and the grip elements may be of same, or different material.
According to an embodiment, the separate grip elements or plates are mounted to the chain members by means of transversally directed pins or screws.
According to an embodiment, the subsequent chain links are connected to each other by means of interlocking elements or surfaces which can be provided on the chain links. There may be for example protruding elements and notches, holes, or other spaces for receiving the protruding elements and thereby forming together turnable joints. Depending on material and structure of the chain link other type on coupling structures can be implemented.
According to an embodiment, the subsequent chain links are connected to each other by means of transverse coupling pins serving as the coupling elements. Further, the separate grip elements or plates can be mounted to the chain members by means of the coupling pins.
According to an embodiment, the chain member comprises a cable carrier serving as a basic chain structure. Then the cable carrier is equipped with the separate grip elements. The grip elements may be flat pieces made of sheet metal and provided with the needed grip shapes. The cable carriers are also known as cable chains, energy chains and drag chains.
According to an embodiment, the chain members may be made of plastic material, composite material, or metal material. Alternatively, the basic chain structure may be made of plastic material and the grip elements may be made of metal material. When plastic or composite basic chain structure is implemented, then the protective casing may be very light in weight and still rigid enough to serve as the protective device.
According to an embodiment, the rigid chain comprises a first chain member and a second chain member both having a plurality of chain links on their opposing sides and wherein subsequent chain links are connected to each other by means of transverse coupling pins. Further, the chain links are provided with the grip elements. In other words, the chain members comprise integrated grip elements which are part of their basic structures. The grip members are structural non-separable parts of the chain links.
According to an embodiment, the device comprises a fastening element at a first end of the protective casing for mounting the device in connection with the rock drilling machine. There are also guide elements at an opposite second end of the protective casing. Then the guide elements are configured to guide the first and second chain members away from the parallel orientation and to thereby disengage the interlocking between the grip elements of the chain members in response to movement of the rigid chain configuration towards the guide elements. In other words, when the rock drilling machine is moved on a feed beam in a drilling direction, the rigid chain moves towards the guide elements mounted to a front end portion of the feed beam and then the guide elements direct the chain members at the front end portion of the feed beam away from each other and allow the forward movement of the rock drilling machine.
The drilling tool is protected during the movement all the way from the rock drilling machine up to the guide elements.
Thus, the protective structure can move aside in a controlled way and can give way to the forward moving rock drilling machine. When the rock drilling machine is moving on the feed beam in the reverse direction, the guide elements direct the chain elements back to the parallel orientation and cause the mating grip elements to interlock with each other and form thereby an extending structure.
The protective structure can be shortened and extended automatically and in a stepless manner.
According to an embodiment, the device comprises a first guide element for the first chain member and a second guide element for the second chain member. The first and second guide elements both comprise a curved chute-like structure having two side walls and connecting bottom part. As an alternative to the chute-like guide element, it is possible to use curved tubular parts or other curved guide surfaces.
According to an embodiment, the device comprises a first and second guide elements both having a substantially U-shaped configuration comprising a backwards curved part. Thereby, the guide elements are configured to direct the disengaged and forward moving chain members into backward direction movement. It can be considered that each chain member is forced to make U-turn at the front end part of the feed beam. Then the disengaged chain members move parallel and on opposing sides of the protective casing when the rock drilling machine is moving on the feed beam forwards in the drilling direction. In other words, the separated chain members move in reverse direction in response to the movement of the rock drilling machine towards the guide elements. An advantage of this embodiment is that the returning chain members take only little space and do not form visibility barriers when moving parallel with the feed beam.
According to an alternative embodiment, the rigid chain is not pushed by means of the rock drilling machine towards the immovably mounted guide elements, but instead the guide elements are moving together with the rock drilling machine. Thereby the device comprises a fastening element at a second end of the protective casing for mounting the device in connection with front end portion of a feed beam of the rock drilling unit. The guide elements are at an opposite first end of the protective casing and are mountable in connection with a rock drilling machine. The guide elements can be mounted directly to the rock drilling machine, or to a carriage on which the rock drilling machine is supported. The guide elements are configured to guide the first and second chain members away from the parallel orientation and to thereby disengage the interlocking between the grip elements of the chain members in response to movement of the guide elements towards the fastening elements.
In other words, when the rock drilling machine is moved on the feed beam in the drilling direction the guide elements coupled to the movement of the rock drilling machine move towards a front end portion of the feed beam. Then the guide elements direct the chain members away from each other and allow the forward movement of the rock drilling machine. The separated chain members can move in a reverse direction on the sides of the rock drilling machine.
Further, structure of the guide elements and other features disclosed in this document apply also for the embodiment wherein the movement guide elements are moving together with the rock drilling machine.
According to an embodiment, the device comprises several absorbent elements mounted to the rigid chain of the protective casing. Then the device comprises a noise insulated tool space inside the protective casing. In other words, the device can serve not only as a physical protective structure preventing contact with rotating drilling components, but also it can provide noise insulation. Thus, the device has dual usage.
According to an embodiment, the device comprises elongated absorbent elements mounted on longitudinal surfaces of the rigid chain. Further, the absorbent elements are made of elastic material, whereby the absorbent elements can be easily bend and they can return into their original shape after bending.
According to an embodiment, the absorbent elements may be made of foamed polymer material or mineral insulation wool, for example.
According to an embodiment, the device comprises longitudinal first absorbent elements mounted vertically on surfaces of both chain members. Then the first absorbent elements are located between opposing chain links of the chain members i.e., between upper and lower chain links. The first absorbent elements are then orientated transverse in relation to an upper surface of a feed beam on which a rock drilling machine is supported.
According to an embodiment, the first absorbent elements may extend as uniform pieces from a first end to an opposite second end of the device. This way, there are no air gaps in the structure of the first absorbent element which is beneficial for the noise insulation.
According to an embodiment, the first absorbent elements are mounted on vertical inner surfaces of the chain members.
According to an embodiment, the device comprises longitudinal second absorbent elements mounted horizontally on outer surfaces of chain links of both chain members. Then the second absorbent elements have parallel orientation in relation to an upper surface of a feed beam on which a rock drilling machine is supported. The second absorbent elements comprise longitudinal mating surfaces facing towards each other and provided with wave-like configurations which match with each other.
According to an embodiment, the second absorbent elements may extend as uniform pieces from a first end to an opposite second end of the device. This way, there are no air gaps in the structure of the second absorbent element which is beneficial for the noise insulation.
According to an embodiment, the wave-like mating surfaces of the second absorbents have sawtooth shapes.
According to an embodiment, the device comprises longitudinal U-shaped cover elements arranged on the chain members. The U-shaped cover elements are configured to cover the longitudinal first and second absorbent elements. In other words, the U-shaped cover elements facing each other can provide the absorbing elements and the entire structure of the device protection against humidity, dirt, and external forces. A further advantage is that the cover elements can improve airtightness and thereby affect positively to noise isolation properties. The cover elements can also provide the device with desired appearance.
According to an embodiment, the cover elements are made of rubber or rubber-like resilient material.
According to an embodiment, the cover elements are made of silicone material which is known also as a silicone rubber.
According to an embodiment, each of the cover elements comprise a vertical side and two horizontal sides. The horizontal sides are provided with longitudinal mating surfaces with wave-like configurations. When the chain members are interlocked, the mating surfaces of the cover elements are facing towards each other and the shapes match with each other.
According to an embodiment, the wave-like edges of the cover elements and the wave-like edges of the second absorbing elements are arranged offset relative to each other, so that the wave-like shapes do not match vertically. This way air tightness can be better and hence the noise insulation properties can be improved.
According to an embodiment, the disclosed solution relates also to a rock drilling unit comprising: a feed beam; a rock drilling machine supported on the feed beam; a feed device for moving the rock drilling machine in a drilling direction and a reverse direction; and a protective device comprising a protective casing surrounding at least a drilling tool mountable to the rock drilling machine. Further, the protective device is in accordance with the features and embodiments disclosed in this document and the protective casing of the protective device comprises a rigid chain.
According to an embodiment, the disclosed solution relates also to a method for providing protection for a drilling tool mounted to a rock drilling machine in a rock drilling unit. The method comprises: surrounding the rotating drilling tool by means of a protective casing; providing the protective casing with a rigid chain; adjusting length of the protective casing automatically in accordance with movements of the rock drilling machine in a drilling direction and reverse direction; directing chain members of the rigid chain into parallel orientation and in contact with each other, and interconnecting grip elements of the chain members by moving the rock drilling machine in the reverse direction; and directing the chain members apart from each other and disengaging the grip elements of the chain members by moving the rock drilling machine in the drilling direction.
According to an embodiment, the method further comprises: directing the chain members apart from each other and disengaging the grip elements of the chain members by pushing the rigid chain towards guide elements mounted to a front part of a feed beam by moving the rock drilling machine in the drilling direction; and guiding the disengaged chain members at the front end part of the feed beam to move in the reverse direction adjacent to side surfaces of the feed beam when the rock drilling machine is moving in the drilling direction.
According to an embodiment, the method further comprises: directing the chain members apart from each other and disengaging the grip elements of the chain members by means of guide elements mounted to the rock drilling machine and moving along with the rock drilling machine towards a front end part of a feed beam of the rock drilling unit; and guiding the disengaged chain members to move in the reverse direction adjacent to side surfaces of the rock drilling machine when the rock drilling machine is moving in the drilling direction.
According to an embodiment, the method further comprises: providing the rigid chain with several absorbent elements for dampening noise transmission from the inside of the protective casing; and moving the absorbent elements along with the chain members.
According to an embodiment, the method further comprises using the rigid chain configuration as a safety device wherein the rigid chain forms a physical shield preventing access to the drilling tool rotatable around its longitudinal axis.
The above disclosed embodiments may be combined in order to form suitable solutions having those of the above features that are needed.

Brief description of the figures

Some embodiments are described in more detail in the accompanying drawings, in which

Figure 1 is a schematic side view of a rock drilling rig for surface drilling and being provided with a protective device;
Figure 2 is a schematic diagram of some features of a protective device;
Figure 3 is a schematic top view of a rigid chain movable in relation to guide elements for opening and closing grip elements of chain members;
Figure 4 is a schematic top view of a rigid chain and guide elements movable in relation to the rigid chain for opening and closing grip elements of chain members;
Figure 5 is a schematic view of a rock drilling unit provided with a protective device surrounding a drilling tool;
Figure 6 is a schematic view showing a mounting of a protective casing to a front end portion of a rock drilling machine;
Figure 7 is a schematic view showing guide elements mounted to a front end portion of a feed beam;
Figure 8 is a schematic view showing assembly of separate grip elements to chain members of a rigid chain;
Figure 9 is a schematic view showing a support structure for guide elements;
Figure 10 is a schematic view showing a support structure for mounting a protective casing to a rock drilling machine;
Figure 11 is a schematic top view of a rock drilling unit provided with a protective casing mounted to a rock drilling machine;
Figure 12 is a schematic top view of a front end portion of a feed beam and guide elements mounted therein;
Figure 13 is a schematic top view of a rock drilling unit provided with a protective casing mounted to a front end portion of a feed beam; and
Figure 14 is a schematic and cross-sectional view of a rock drilling unit provided with a protective casing which comprises several noise absorbing elements.

For the sake of clarity, the figures show some embodiments of the disclosed solution in a simplified manner. In the figures, like reference numerals identify like elements.

Detailed description of some embodiments

Figure 1 discloses a rock drilling rig 1. The rock drilling rig 1 comprises a movable carrier 2 and at least one boom 3 connected to the carrier 2. At a distal end portion of the boom 3 is a drilling unit 4. The drilling unit 4 comprises a feed beam 5 and a rock drilling machine 6 movable by means of a feed device 7 on the feed beam 5. The rock drilling machine 6 may comprise a rotating device for rotating R a drilling tool 8. The rock drilling machine 6 may also comprise an impact device, which generates impact pulses for the drilling tool 8. A protective device 9 is arranged to surround the drilling tool 8. The protective device 9 may provide physical protection by preventing access to the rotating drilling tool 8 and may also serve as a noise dampening structure for lowering noise pressure level caused by the rock drilling machine 6 during drilling operation. The protective device 9 is in accordance with the features and embodiments disclosed in this document.
In Figure 1 a surface rock drilling rig is disclosed. However, it is of course possible to implement the disclosed protective device also in other type of drilling rigs and drilling machines. Thereby, the disclosed solution may be implemented in rock drilling rigs intended for underground drilling and may be used also in rotary and DTH drilling as well as in exploration drilling.
Figure 2 discloses that a protective device 9 comprises a protective casing 10 which comprises a rigid chain 11. The rigid chain 11 can serve as a physical shield 12 providing safety by preventing possibility of an operator or anyone else working at a drilling work site from clinging to the rotating drilling tool. The solution can also serve as a noise isolating structure 13 when the rigid chain 11, which is serving as a basic structure, is provided with sound absorbing and isolating elements 14. Figure 2 further discloses that rigid chain 11 comprises two parallel chain members 15 and grip elements 16 for connecting them.
Figure 3 discloses a basic principle of a rigid chain 11 in a simplified manner. The rigid chain 11 is provided with two adjacent and parallel chain members 15a, 15b both having grip elements 16 facing towards each other and configured to interlock the adjacent chain members 15a, 15b together. When the rigid chain 11 is moved towards guide elements 17 shape locking of the grip elements 16 opens and thereby the chain members 15a, 15b are disengaged from each other. When the rigid chain 11 is moved into an opposite direction, then guide elements 17 engage the grip elements 16 together. The guide elements 17 may be mounted immovably by means of a fastening device 18 comprises needed supports 19, for example. Each grip element 16 comprises a protrusion 20 and a notch 21 both having round shapes. The opposing grip elements 16 are configured to interlock with each other so that the protrusions 20 match with the opposing notches 21. The grip elements 16 may be integrated to structures of chain members 15a, 15b or they may be separate pieces. An exemplary mounting 22 of the grip elements 16 is also shown.
Figure 4 discloses a rigid chain 11 having similar kind of basic structure but having different operating principle for opening and closing its chain members 15a, 15b. In Figure 4 guide elements 17 are moved and the rigid chain 11 is mounted immovably at its one end by means of a fastening device 23.
Figure 5 discloses a rock drilling unit 4 which comprises a protective device 9 forming a protective casing 10 and covering a portion between a rock drilling machine 6 and a front end portion 5a of a feed beam 5. The protective device 9 comprises a rigid chain 11 and there are grip elements 16 for opening and closing the structure. At a front end portion 5a of the feed beam 5 there are guide elements 17 and the rigid chain 11 is disengaged when being moved towards the guide elements 17 by means of the rock drilling machine 6. The protective casing is a rigid structure in directions y and x, and is adjustable in its length direction i.e., in z direction.
Figure 6 discloses that a first end 10a of a protective casing 10 may be mounted by means of a fastening element 24 in connection with the rock drilling machine 6. The fastening element 24 may be mounted directly to the rock drilling machine 6, such on a flushing housing 25. Alternatively, the fastening element 24 may be mounted to a carriage 26 on which the rock drilling machine 6 is movable on a feed beam 5.
Figure 7 discloses that there are guide elements 17 at a second end 10b of a protective casing 10. As can be seen, the guide elements 17 may be U-shaped elements which are capable of directing chain members 15a, 15b apart and towards a rock drilling machine. In Figure 7 only chain members 15a, 15b are shown inside the U-shaped elements for clarity reasons.
Figure 8 discloses a possible structure of a rigid chain 11 comprising two chain members 15a, 15b, with several subsequent chain links 27 connected to each other in a turnable manner. As can be seen, there are chain links 27 in two horizontal layers which may be connected to each other by means of vertical elements 28, for example. Grip elements 16 may be mounted on outer surfaces of the chain links 27 by means of transverse pins 29 or by utilizing screw mounting.
Figure 9 discloses that guide elements 17 may comprise a first chute-like guide element 30a for a first chain member and a second chute-like guide element 30b for a second chain member.
Figure 10 discloses a fastening device 24 comprising a collar part 31 which can be fastened around a front end part of a rock drilling machine.
Figure 11 discloses a protective device 9 comprising a rigid chain 11 which is fastened to a rock drilling machine 6 and is moved together with the rock drilling machine 6 towards guide elements 17 during drilling when the rock drilling machine 6 is moved in a drilling direction A. Arrows at the guide elements 17 indicate that separated chain members move on a side of a rock drilling unit 4 in a reverse direction B.
Figure 12 shows that there may be support elements 32 for supporting disengaged chain members which are guided to move in a reverse direction B. The support elements 32 may be supported to side surfaces of a feed beam and may have for example tubular configuration. Alternatively, it is possible to implement tracks with rollers or slide elements for providing well supported and controlled movement in the reverse direction B.
Figure 13 discloses that a rock drilling machine 6 may be provided with guide elements 17 for disengaging and engaging grip elements 16 of chain members for opening and closing a protective casing 10. The guide elements 17 may comprise curved guide surfaces which can direct the chain members to pass the rock drilling machine 6 moving in a drilling direction A. There may be support elements for supporting the chain members.
At a second end 10b of the protective casing 10 is a fastening element 23 for mounting the protective casing 10 in connection with front end portion 5a of a feed beam 5. When the guide elements 17 move in the drilling direction A towards the fastening element 23, the grip elements 16 are disengaged, and when they are moving in a reverse direction B, the grip elements 16 re-connect to each other.
Figure 14 discloses that a protective casing 10 may comprise several absorbent elements 33, 34 mounted to a rigid chain 11 for forming a noise insulated tool space 35 inside which a drilling tool 8 is located. There may be longitudinal first absorbent elements 33 mounted vertically on surfaces of chain members 15a, 15b, and longitudinal second absorbent elements 34 mounted horizontally on outer surfaces of chain links 16. Further, the protective cover 10 may comprise longitudinal U-shaped cover elements 36 arranged on the chain members 15a, 15b.
The drawings and the related description are only intended to illustrate the idea of the invention. In its details, the invention may vary within the scope of the claims.

Claims

A protective device (9) for a rock drilling unit (4), wherein the device (9) comprises:
a protective casing (10) mountable to surround a drilling tool (8) connectable to a rock drilling machine (6) of the rock drilling unit (4);

characterized in that,

the protective casing (10) comprises at least one rigid chain (11) provided with two adjacent and parallel chain members (15a, 15b) both having grip elements (16) facing towards each other and configured to interlock the adjacent chain members (15a, 15b) together and configured to allow the chain members (15a, 15b) to disengage from each other in response to movement of the rock drilling machine (6) in a drilling direction (A) and in a reverse direction (B) .
The device as claimed in claim 1, characterized in that
the rigid chain (11) comprises a first chain member (15a) and a second chain member (15b) both having a plurality of chain links (27) on their opposing sides and wherein subsequent chain links (27) are connected to each other by means of coupling elements allowing turnable connections between subsequent chain links (27);

and wherein the grip elements (16) are separate pieces mounted on outer surfaces of the first and second chain members (15a, 15b).
The device as claimed in claim 1, characterized in that,
the rigid chain (11) comprises a first chain member (15a) and a second chain member (15b) both having a plurality of chain links (27) on their opposing sides and wherein subsequent chain links (27) are connected to each other by means of coupling elements allowing turnable connections between subsequent chain links (27);

and wherein the chain links (27) are provided with the grip elements (16).
The device as claimed in any one of the preceding claims 1 - 3, characterized in that the device (9) further comprises:
a fastening element (24) at a first end (10a) of the protective casing (10) for mounting the device (9) in connection with the rock drilling machine (6);

guide elements (17) at an opposite second end (10b) of the protective casing (10);

and wherein the guide elements (17) are configured to guide the first and second chain members (15a, 15b) away from the parallel orientation and to thereby disengage the interlocking between the grip elements (16) of the chain members (15a, 15b) in response to movement of the rigid chain (11) configuration towards the guide elements (17).
The device as claimed in any one of the preceding claims 1 - 3, characterized in that the device (9) further comprises:
a fastening element (23) at a second end (10b) of the protective casing (10) for mounting the device (9) in connection with front end portion (5a) of a feed beam (5) of the rock drilling unit (4);

guide elements (17) at an opposite first end (10a) of the protective casing (10) and being mountable in connection with a rock drilling machine (6) of the rock drilling unit (4);

and wherein the guide elements (17) are configured to guide the first and second chain members (15a, 15b) away from the parallel orientation and to thereby disengage the interlocking between the grip elements (16) of the chain members (15a, 15b) in response to movement of the guide elements (17) towards the fastening element (23).
The device as claimed in any one of the preceding claims 1 - 5, characterized in that,
the device (9) comprises several absorbent elements (33, 34) mounted to the rigid chain (11) of the protective casing (10), whereby the device (9) comprises a noise insulated tool space (35) inside the protective casing (10).
The device as claimed in claim 6, characterized in that,
the device (9) comprises longitudinal first absorbent elements (33) mounted vertically on surfaces of both chain members (15a, 15b), whereby the first absorbent elements (33) are located between opposing chain links (16) of the chain members (15a, 15b).
The device as claimed in claim 6 or 7, characterized in that,
the device (9) comprises longitudinal second absorbent elements (34) mounted horizontally on outer surfaces of chain links (16) of both chain members (15a, 15b);

and the second absorbent elements (34) comprise longitudinal mating surfaces facing towards each other and provided with wave-like configurations which match with each other.
The device as claimed in claims 6 - 8, characterized in that,
the device (9) comprises longitudinal U-shaped cover elements (36) arranged on the chain members (15a, 15b) and covering the longitudinal first and second absorbent elements (33, 34).
A rock drilling unit (4) comprising:
a feed beam (5);

a rock drilling machine (6) supported on the feed beam (5);

a feed device (7) for moving the rock drilling machine (6) in a drilling direction (A) and a reverse direction (B); and

a protective device (9) comprising a protective casing (10) surrounding at least a drilling tool (8) mountable to the rock drilling machine (6);

characterized in that

the protective device (9) is in accordance with the device (9) disclosed in the previous claims 1 - 9 and the protective casing (10) of the protective device (9) comprises a rigid chain (11).
A method for providing protection for a drilling tool (8) mounted to a rock drilling machine (6) in a rock drilling unit (4),
wherein the method comprises:
surrounding the rotating drilling tool (8) by means of a protective casing (10);

characterized by

providing the protective casing (10) with a rigid chain (11);

adjusting length of the protective casing (10) automatically in accordance with movements of the rock drilling machine (6) in a drilling direction (A) and reverse direction (B);

directing chain members (15a, 15b) of the rigid chain (11) into parallel orientation and in contact with each other, and interconnecting grip elements (16) of the chain members (15a, 15b) by moving the rock drilling machine (6) in the reverse direction (B);

and directing the chain members (15a, 15b) apart from each other and disengaging the grip elements (16) of the chain members (15a, 15b) by moving the rock drilling machine (6) in the drilling direction (A).
The method as claimed in claim 11, characterized by
directing the chain members (15a, 15b) apart from each other and disengaging the grip elements (16) of the chain members (15a, 15b) by pushing the rigid chain (11) towards guide elements (17) mounted to a front part (5a) of a feed beam (5) by moving the rock drilling machine (6) in the drilling direction (A);

and guiding the disengaged chain members (15a, 15b) at the front end part (5a) of the feed beam (5) to move in the reverse direction (B) adjacent to side surfaces of the feed beam (5) when the rock drilling machine (6) is moving in the drilling direction (A).
The method as claimed in claim 11, characterized by
directing the chain members (15a, 15b) apart from each other and disengaging the grip elements (16) of the chain members (15a, 15b) by means of guide elements (17) mounted to move along with the rock drilling machine (6) towards a front end part (5a) of a feed beam (5) of the rock drilling unit (4);

and guiding the disengaged chain members (15a, 15b) to move in the reverse direction (B) adjacent to side surfaces of the rock drilling machine (6) when the rock drilling machine (6) is moving in the drilling direction (A).
The method as claimed in any one of the preceding claims 11 - 13, characterized by
providing the rigid chain (11) with several absorbent elements (33, 34) for dampening noise through the protective casing (10);

and moving the absorbent elements (33, 34) along with the chain members (15a, 15b).
The method as claimed in any one of the preceding claims 11 - 14, characterized by
using the rigid chain (11) configuration as a safety device wherein the rigid chain (11) forms a physical shield preventing access to the drilling tool (8) rotatable around its longitudinal axis.