AU2010212735B2

AU2010212735B2 - Method for manipulating rodlike pieces, centralizer and rock drilling unit

Info

Publication number: AU2010212735B2
Application number: AU2010212735A
Authority: AU
Inventors: Mikko Merilainen; Juha Piipponen
Original assignee: Sandvik Mining and Construction Oy
Current assignee: Sandvik Mining and Construction Oy
Priority date: 2009-02-12
Filing date: 2010-02-11
Publication date: 2013-02-07
Anticipated expiration: 2030-02-11
Also published as: EP2396496A1; CN102292515A; FI20095135A0; JP2012517544A; AU2010212735A1; CA2748173C; CA2748173A1; FI121483B; WO2010092236A1; EP2396496B1; FI20095135A; ZA201106320B; JP5347036B2; CN102292515B; EP2396496A4

Abstract

The invention relates to a method for manipulating drill rods, to a centralizer and to a rock drilling unit. It is possible to introduce rods (9, 18) into the centre (K) of a rock drilling unit (4) or a bolting device by means of a changing device (13), and to remove from the centre. The rod locating in the centre is supported by a centralizer (16), through the central opening (20) of which the rod is arranged. The centralizer comprises a closing element (22) which is opened and closed in accordance with the operation of the changing device. The turning of the changing device affects a push rod (25) which releases the shape-locking of the closing element and transfers it to the open position. When the changing device is turned back to the normal position, a force member (26) returns the push rod to the normal position and simultaneously the closing element is shape-locked again. In the closed position the closing element is rigidly shape locked.

Description

WO 2010/092236 PCT/F12010/050089 METHOD FOR MANIPULATING RODLIKE PIECES, CENTRALIZER AND ROCK DRILLING UNIT BACKGROUND OF THE INVENTION [0001] The invention relates to a method for manipulating rodlike pieces on a feed beam of a excavation apparatus. Drill rods, rock bolts and the like rodlike pieces used in excavation industry are introduced into the centre of a excavation unit and away therefrom by means of a changing device. During the operation, rods locating in the centre are supported with one or more cen tralizers arranged on the feed beam. For a rod change the excavation appara tus and the centralizer are driven to a changing station, where the changing device may be turned in a direction transverse to the feed beam, whereby a closing element of the centralizer opens at the same time. When the changing device is turned back to its normal position the closing element of the central izer will close. [0002] The invention further relates to a centralizer and a rock drill ing unit provided with the centralizer. [0003] The field of the invention is described in greater detail in the preambles of the independent claims of the application. [0004] Rock drilling employs a rock drilling unit, whose rock drilling machine and a tool coupled thereto produces a drill hole in material to be treated. The tool may comprise a drill rod and a drill bit connected to its distal end, or if drilling of long drill holes is concerned, there is a plurality of drill rods connected successively to form an extension drill rod arrangement. The drill rods are often relatively long, and therefore it is necessary to support them in the portion extending between the drill machine and the drill hole by means of a centralizer arranged on the feed beam. The centralizer comprises a central hole through which the rod is arranged. At the edge of the central hole there is a closing element that may be opened for the duration of the drill rod changes. Centralizers may also be employed in bolting devices, for instance. [0005] Publication Fl 74 778 sets forth that the closing element is held in a closed position by means of spring force. However, locking the clos ing element by means of a spring has been found insufficient.

2 BRIEF DESCRIPTION OF THE INVENTION [0006] The object of the present invention is to provide a novel and improved method for manipulating rods and further a novel and improved centralizer and a rock drilling unit provided with the same. 5 [0007] In an embodiment, there is provided a method for manipulating rodlike pieces in a excavation apparatus, the method comprising: performing operations relating to a drill hole with a excavation unit which comprises a excavation apparatus; a feed beam and a feed device, by means of which the excavation apparatus is moved on the feed beam in a feed 10 direction and in a reverse direction: introducing a rod into the centre of the unit and out of the centre, respectively, by means of a changing device belonging to the excavation unit; connecting in the centre the rod to the excavation apparatus; supporting the rod, during the operation directed to the drill hole, by is means of at least one centralizer in the portion between the front part of the excavation apparatus and the front part of the feed beam; transferring, after the operation, the excavation apparatus and the centralizer in the reverse direction to a changing station; turning the changing device in a direction transverse to the feed 20 beam to the centre, whereby the same turning movement also affects a guide member of the centralizer and opens a closing element of the centralizer to an open position so as to receive the rod in the centre or to remove the rod from the centre; and locking the closing element of the centralizer in a shape-locking 25 manner while in the closed position and preventing the closing element from being opened by the effect of the forces exerted from the rod on the closing element. [0008] In another embodiment, there is provided a centralizer comprising: 30 a frame that is arrangeable on a feed beam of a excavation apparatus; 3930009_1 (GHIMatters) P87447.AU 11/01/13 2a a central opening through which a rodlike excavation implement may be arranged to pass while in the centre; at least one closing element having a closed position and an open position, whereby the closing element, while closed, is arranged to close at 5 least partly a change opening at the circumference of the central opening and to prevent the implement from escaping in the transverse direction from the central opening; at least one force element that is arranged to provide a closing force so as to retain the closing element in the closed position and 10 at least one guide member that is arranged to transmit the force to the closing element so as to transfer the closing element from the closed position to the open position; and wherein the closing element is locked with shaped-locked locking means while in closed position, whereby opening of the closing element 15 by the effect of the forces exerted from the drill rod onto the closing element is prevented. [0009] In a further embodiment, there is provided a rock drilling unit comprising: a rock drilling machine to which at least one drill rod is connectable; 20 a feed beam to which the rock drilling machine is supported; a feed device by means of which the rock drilling machine may be moved on the feed beam in the feed direction and in the reverse direction; at least one changing device for moving the drill rod into the centre of the drilling unit and away from the centre, respectively; 25 turning means for turning the changing device in a direction transverse to the feed beam; at least one centralizer for supporting the drill rod locating in the centre, in the portion extending between the front end of the rock drilling machine and the front end of the feed beam; 30 the centralizer comprising: a frame; a central opening, through which the drill rod may be arranged to pass while in the centre; at least one closing element having a closed position and an open position, whereby the closing element is arranged, while closed, to close at least partly a change opening at 3930009_1 (GHMatters) P87447.AU 11/01/13 2b the circumference of the central opening and to prevent the drill rod from escaping from the central opening in the transverse direction; at least one force member that is arranged to provide closing force for retaining the closing element in the closed position; and a guide member that is arranged to transmit 5 an opening force to the closing element so as to transfer the closing element from the closed position to the open position; and wherein the centralizer is arranged to move during drilling on the feed beam in the feed direction together with the rock drilling machine and correspondingly in the reverse direction, when the rock drilling machine and the 10 centralizer are transferred to the changing station; and further, wherein the turning of the changing device at the changing station is arranged to affect the guide member of the centralizer and to transfer the closing element into the open position so as to receive the drill rod in the centre or to remove the drill rod from the centre; 15 and the closing element of the centralizer is locked in a shape locking manner while in the closed position, whereby the opening of the closing element by the effect of the forces exerted from the drill rod onto the closing element is prevented. [0010] Generally speaking, the basic idea of the invention is that the 20 closing element of the centralizer is locked in a shaped-locked manner, while in a closed position. [0011] The invention has an advantage that forces exerted from the drill rod or another excavation implement to the closing element are not capable of opening the shaped-locked locking during normal operation. The force 25 produced by a force device only needs to keep the mutual position of the shape-locking members unchanged, and there is no need to design it such that it would be able to receive all the opening forces exerted from the drill rod to the closing element. The locking of the closing element being rigid, it is possible to make sure in all situations that the rod is retained in the centralizer. This is a 30 clear advantage over the prior art solutions, in which the closing element is kept closed only by means of spring force. [0012] The basic idea of an embodiment is that the closing element of the centralizer is locked by means of mutually shape-locked locking members. 39300091 (GHMatters) P87447.AU 11/01/13 2c [0013] The basic idea of an embodiment is that the mutually shape locking locking members affecting the closing element include at least two elongated transfer openings and a pivot pin locating therebetween and sliding along said transfer openings. 5 3930009_1 (GHMatters) P87447.AU 11/01/13 WO 2010/092236 PCT/F12010/050089 3 [0014] The basic idea of an embodiment is to transmit a motion opening the shape locking to the locking members by means of a push rod that is arranged to move substantially only in its longitudinal direction. [0015] The basic idea of an embodiment is that the frame of the centralizer comprises a first elongated transfer opening whose centre line is arranged in parallel with a guide member. The closing element comprises a second elongated transfer opening the centre line of which is curved and which is arranged transversely to the first transfer opening. Through said transfer openings there is arranged a transverse pivot pin which the guide member moves in a linear direction. The pivot pin and the transfer openings are ar ranged to form a mutual shape locking so as to retain the closing element in the closed position. When the guide member moves the pivot pin in the direc tion of the first transfer opening, said shape locking opens up and at the same time the closing element starts moving towards the open position. [0016] The basic idea of an embodiment is that in the turning mechanism of a changing device there is coupled a separate push surface that is arranged to move with the changing device transversely to the feed beam. The push surface is arranged to push a push rod of the centralizer. The push surface may be arranged to move substantially only in a linear direction by means of an articulation mechanism. BRIEF DESCRIPTION OF THE DRAWINGS [0017] Some embodiments of the invention will be described in greater detail in connection with the attached drawings, in which Figure 1 is a schematic side view of a excavation rig that is provided with two booms and with a drilling unit and a bolting device arranged thereon, Figure 2 is a schematic view of a rock drilling unit, Figure 3 is a schematic view of the rock drilling unit, seen in the di rection of the feed beam, in a situation where the centralizer is in a closed po sition, Figure 4 is a schematic view of the rock drilling unit of Figure 3 in a situation where the centralizer is driven to a changing station and a rod chang ing device is turned to the centre, Figures 5 and 6 show schematically and in perspective the opera tion of the centralizer and WO 2010/092236 PCT/F12010/050089 4 Figure 7 shows further schematically the shape locking of the clos ing element and forces exerted thereon. [0018] For the sake of clarity, in the figures some embodiments of the invention are shown in a simplified manner. Like reference numerals refer to like parts in the figures. DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION [0019] The excavation rig 1 shown in Figure 1 comprises a mobile carrier 2, on which there is arranged one or more booms 3. The first boom 3a is a drill boom and it is provided with a rock drilling unit 4. The drilling unit 4 comprises a rock drilling machine 5 which may be moved on the feed beam 6 by means of a feed device 7. To the rock drilling machine 5 it is possible to connect a tool 8 that may comprise a plurality of successive drill rods 9 which are interconnected with connecting means, such as threaded connections. Fur ther, at the end of the most distal drill rod there is a drill bit 10 whose drill but tons cut a drill hole 12 in the rock 11. The rock drilling machine 5 may com prise a percussion device which delivers impact pulses to the tool 8, which transmits them to the drill bit 10 and further to the rock 11 to be broken. The rock drilling machine 5 may also comprise a rotating device whereby the tool 8 may be rotated about its longitudinal axis during drilling. The drilling unit 4 may also be provided with a rod magazine 13 that is supported on the feed beam 6. The rod magazine 13 allows storage of extension rods 9 necessary for long hole drilling and other drilling tools. In connection with the rod magazine 13 there is at least one changing device 14 wherewith drilling tools may be dis placed between the rod magazine 13 and the drilling axis, i.e. the centre K. In the portion at the distal end of the feed beam 6 there may be a retainer 15 whose jaws may grip the tool 8 and concentrate it to the centre K. Further, in the portion between the rock drilling machine 5 and the retainer 15 there may be one or more centralizers 16 arranged to move on the feed beam 6 together with the rock drilling machine 5. [0020] The second boom 3b of the excavation rig 1 of Figure 1 is provided with a second excavation unit 40, which comprises an excavation apparatus 17 for manipulating excavation implements 18, such as rock bolts, injection pipes or the like. It may be necessary to support also these imple ments with a centralizer 16. Consequently, in connection with a bolting device, for instance, there may be a changing device 14 and a magazine for storing WO 2010/092236 PCT/F12010/050089 5 the rodlike implements. Further, it may be provided with a centralizer 16 in ac cordance with the invention and with means for operating it. [0021] Figure 2 shows a rock drilling unit 4 whose feed beam 6 is provided with a rod magazine 13, wherein drill rods 9 or other rodlike imple ments necessary for drilling may be stored. A changing device 14 may be ar ranged in connection with the rod magazine 13. At the distal end of the feed beam 6 there is a retainer 15. A centralizer 16 is supported to the feed beam 6 and it is arranged to move in accordance with the movements of the rock drill ing machine 5. In a situation shown in Figure 2 the rock drilling machine 5 and the centralizer 16 are transferred in reverse direction B to a changing station V, where it is possible to introduce the drill rod 9 into the centre K from the rod magazine 13 or where the drill rod 9 may be removed from the centre K to be stored in the rod magazine. [0022] Figure 3 shows a centralizer 16 in accordance with the in vention and means for operating it. The centralizer 16 comprises a frame 19 by means of which it may be arranged movably on the feed beam 6. Further, the centralizer 16 is provided with a central opening 20, through which a rodlike implement, such as a drill rod, for instance, is arrangeable. The central open ing 20 is arranged at the centre K of the rock drilling unit 4 or another excava tion apparatus. At the circumference of the central opening 20 there is a change opening 21, which may be closed partly or completely with a closing element 22 that may be a kind of a jaw piece, which may be connected to the frame 19 with a pivoted link 23. The closing element 22 may be opened such that the drill rod or the like may be arranged through the change opening 21 into the centre K or taken away from the centre K. When the closing element 22 is closed, the escape of the drill rod from the central opening 20 is pre vented. The opening movement of the closing element 22 is arranged to be dependent on the operation of the changing device 14 at the changing station. The turning of the changing device 14 from the normal position shown in Fig ure 3 to a situation shown in Figure 4 is arranged to provide opening of the closing element 22 and release of the change opening 21. [0023] Figure 3 also shows a guide member 24, which is arranged to transmit a movement necessary for opening the closing element 22. The guide member 24 may be an elongated push rod 25 that may be supported to the frame 19 such that it may substantially move only in its longitudinal direc tion. In that case the push rod 25 only has a linear movement L to be transmit- WO 2010/092236 PCT/F12010/050089 6 ted to the operating mechanism of the closing element 22. Closing force, which may be produced with one or more force members 26, such as a spring or the like, is arranged to affect the closing element 22. The force member 26 may be arranged to affect the push rod 25 and to transfer it to its normal position, when no external force is exerted on the push rod. The push rod 25 may comprise a roll or a like rolling means 27 at the end of the rod on the side of the changing device 14, which enables movement of the centralizer in relation to the chang ing device, when threaded connections are screwed open or closed and an axial movement is required. [0024] Figure 3 also shows that the changing device 14 and the rod magazine 13 integrated therein may be connected to a turning rod 28 which is parallel with the feed beam 6 and which may be turned about its longitudinal axis with a suitable turning device, whereby the feed station 29 of the changing device 14 may be applied to the centre K. The push rod 25 of the centralizer 16 is pushed in substantially linear direction by means of a push surface 30. The push surface 30 is arranged at an axial distance to the changing device 14 and it is connected by means of an articulation mechanism 31 to the turning rod 28 and to the feed beam 6. Turning of the turning rod 28 affects the movements of both the changing device 13 and the push surface 30. The ar ticulation mechanism 31 is intended to keep the travel direction of the push surface 30 in the same direction with the push rod 25 so that the push rod would not be subjected to any unnecessary stresses. The articulation mecha nism 31 may comprise at least one first arm 32 articulated to the feed beam 6 and at least one second arm 33 articulated to the turning rod 28. The turning rod 28 may comprise a crank 34 that may transmit the turning movement with the pin 35 or the like transmission member included therein to an elongated transfer opening 36 in the second arm 33. By means of the transfer opening 36 it is possible to arrange a relatively short travel for the push surface 30 as com pared with the travel required by the changing device 13. By changing the di mensions of the transfer opening 36 it is possible to adjust the travel to be ob tained. [0025] It appears still in Figures 3 and 4 that the push rod 25 may be connected to a transverse pivot pin 37, which may be arranged to move guided by the first elongated transfer opening 38 provided in the frame of the centralizer 16. The centre line of the transfer opening 38 is arranged to be sub stantially in parallel with the linear movement of the push rod 25. The closing WO 2010/092236 PCT/F12010/050089 7 element 22 may further comprise a second transfer opening 39 whose centre line may be transverse to the first transfer opening 38. In addition, the centre line of the second transfer opening 39 may be curved. The first transfer open ing 38 ensures the linear movement of the push rod 25, and on the other hand, together with the second transfer opening 39 and the pivot pin 37, it constitutes shape locking for the closing element 22. In a locking situation the force mem ber 26 only needs to hold the shape-locking elements in predefined positions with respect to one another, whereby the rigid shape locking receives the forces exerted on the closing element 22, and locking is not dependent on the force generated by the force member 26. [0026] In some cases the second transfer opening 39 may com prise, in the outermost portion thereof, a locking notch (not shown) or the ra dius of curvature in the transfer opening 39 may change at the outermost por tion thereof, whereby the shape locking between the pivot pin 37 and the transfer opening 39 is additionally ensured. Only after the push rod 25 has pushed the pivot pin 37 off the locking notch, the pivot pin 37 is able to slide along the transfer opening 39 and to turn the closing element 22 to the open position in relation to the articulation 23. [0027] Figures 5 and 6 further illustrate, in perspective view, co operation between the centralizer 16 and the changing device 13. [0028] Figure 7 shows the operation and shape locking of the clos ing element 22 and forces exerted thereon. From the drill rod 9 locating in the central opening 20 transverse forces F2, F3 are exerted on the closing element 22, which forces tend to turn the closing element 22 towards the open position in relation to the pivoted link 23. A force FR is then exerted on the pivot pin 37, and the transfer opening 38 forms a counter force FT to the force FR. Further, as the drill rod 9 rotates, friction forces are generated in the central opening 20 between the drill rod 9 and the closing element 22. These produce a turning force F1 which also tends to open the closing element 22 in relation to its piv oted link 23. Also the force F1 produces in the pivot pin 37 a force FR, shown in the figure, to which the shape locking forms a counter force FT. Thus, the closing element 22 may not turn into the open position by the effect of any force transmitted through the drill rod. Only the linear movement L of the pivot pin 37 may open the shape locking in the direction guided by the transfer opening 38. When the pivot pin 37 slides in the transfer opening towards its extreme position on the right, the pivot pin 37 pushes the closing element 22 8 simultaneously in relation to its pivoted link 23 towards the open position. When the closing element 22 is completely open, the pivot pin 37 is located in the right-hand extreme positions, as can be seen in Figures 4 and 6. [0029] It is clear that the rigid shape locking may also be implemented 5 in other ways than those described in the above examples. For instance, it is possible that the shapes and mutual directions of the transfer openings are arranged in some other way. Even then a rigid locking is to be provided between the transfer openings and the pivot pin in relation to the directions of forces opening the closing element. 10 [0030] Even though Figures 3 to 7 concern a rock drilling unit, the solutions or operating principles presented therein may also be applied to a bolting device or any other excavation apparatus intended for manipulating rodlike pieces in an excavation. [0031] In some cases the features set forth in the present application 15 may be used as such, irrespective of other features. On the other hand, the features set forth in the present application may be combined, when necessary, to provide various combinations. [0032] The drawings and the relating specification is only intended to illustrate the inventive idea. The details of the invention may vary within the 20 scope of the claims. [0033] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the 25 presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. [0034] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any 30 other country. 2721738_1 (GHMatters) PB7447.AU 30/06/11

Claims

1. A method for manipulating rodlike pieces in an excavation apparatus, the method comprising: 5 performing operations relating to a drill hole with a excavation unit which comprises a excavation apparatus; a feed beam and a feed device, by means of which the excavation apparatus is moved on the feed beam in a feed direction and in a reverse direction; introducing a rod into the centre of the unit and out of the centre, 1o respectively, by means of a changing device belonging to the excavation unit; connecting in the centre the rod to the excavation apparatus; supporting the rod, during the operation directed to the drill hole, by means of at least one centralizer in the portion between the front part of the excavation apparatus and the front part of the feed beam; 15 transferring, after the operation, the excavation apparatus and the centralizer in the reverse direction to a changing station; turning the changing device in a direction transverse to the feed beam to the centre, whereby the same turning movement also affects a guide member of the centralizer and opens a closing element of the centralizer to an open 20 position so as to receive the rod in the centre or to remove the rod from the centre; and locking the closing element of the centralizer in a shape-locking manner while in the closed position and preventing the closing element from being opened by the effect of the forces exerted from the rod on the closing 25 element.

2. The method of claim 1, comprising locking the closing element of the centralizer by means of mutually shape-locking locking means; transmitting a movement opening the shape-locking to the locking means 30 by means of a push rod, which is arranged to move substantially only in its longitudinal direction; pushing the closing element open with the linear movement of the push rod and closing the closing element of the centralizer at the same time as the 35 changing device is turned away from the centre and shape locking of the closing element is performed. 2721738_1 (GHMatters) P87447.AU 30/06/11 10

3. The method of claim 2, comprising transmitting a pushing movement to the push rod of the centralizer by means of a separate push surface connected to a turning mechanism of the changing device. 5

4. The method of claim 3, comprising transmitting an opening movement to the push surface from the turning mechanism of the changing device by means of an articulation mechanism and retaining the direction of the push surface substantially unchanged in relation to the push rod during the opening movement by means of the 10 articulation mechanism.

5. The method in accordance with any one of the preceding claims, comprising storing a plurality of rods in a rod magazine locating in the changing device and supporting the rods in parallel side by side. 15

6. The method in accordance with any one of the preceding claims, comprising directing the shape locking particularly against the forces which are produced by the rotation of the rod and which tend to generate a torque in the closing element in its opening direction. 20

7. A centralizer comprising: a frame that is arrangeable on a feed beam of an excavation apparatus; a central opening through which a rodlike excavation implement may be arranged to pass while in the centre; at least one closing element having a closed position and an open 25 position, whereby the closing element, while closed, is arranged to close at least partly a change opening at the circumference of the central opening and to prevent the implement from escaping in the transverse direction from the central opening; at least one force element that is arranged to provide a closing force so 30 as to retain the closing element in the closed position and at least one guide member that is arranged to transmit the force to the closing element so as to transfer the closing element from the closed position to the open position; and wherein the closing element is locked with shaped-locked locking 35 means while in closed position, whereby opening of the closing element by the effect of the forces exerted from the drill rod onto the closing element is prevented. 27217381 (GHMatters) P87447.AU 30/06/11 11

8. The centralizer of claim 7, wherein the closing element comprises an elongated transfer opening; the guide member is connected to the closing element with a pivot pin that is arranged to slide in the transfer opening, when an opening movement is 5 directed to the guide member; and the mutual movement of the pivot pin and the transfer opening is arranged to open the shape locking of the closing element and to transfer the closing element to the open position.

9. The centralizer of claim 7 or 8, wherein 10 the guide member is arranged to direct only a linear movement to the closing element.

10. The centralizer of claim 9, wherein the guide member is a push rod that is supported to the frame and that is arranged to move in relation to the frame only in its longitudinal direction. 15

11. The centralizer in accordance with any one of the preceding claims 7 to 10, wherein the frame comprises a first elongated transfer opening whose centre line is arranged to be in parallel with the guide member; the closing element comprises a second elongated transfer opening the 20 centre line of which is curved and which is arranged transversely to the first transfer opening; through said transfer openings there is arranged a transverse pivot pin; the pivot pin and the transfer openings are arranged to form a mutual shape locking to retain the closing element in the closed position; 25 and the moving of the pivot pin with the guide element in the direction of the first transfer opening is arranged to open said shape locking.

12. The centralizer of any one of the preceding claims 7 to 11, wherein at the second end of the push rod there is a rolling means.

13. A rock drilling unit comprising: 30 a rock drilling machine to which at least one drill rod is connectable; a feed beam to which the rock drilling machine is supported; a feed device by means of which the rock drilling machine may be moved on the feed beam in the feed direction and in the reverse direction; at least one changing device for moving the drill rod into the centre of the 35 drilling unit and away from the centre, respectively; turning means for turning the changing device in a direction transverse to the feed beam; 2721738_1 (GHMatters) P87447.AU 30/06/11 12 at least one centralizer for supporting the drill rod locating in the centre, in the portion extending between the front end of the rock drilling machine and the front end of the feed beam; the centralizer comprising: a frame; a central opening, through which the 5 drill rod may be arranged to pass while in the centre; at least one closing element having a closed position and an open position, whereby the closing element is arranged, while closed, to close at least partly a change opening at the circumference of the central opening and to prevent the drill rod from escaping from the central opening in the transverse direction; at least one force 10 member that is arranged to provide closing force for retaining the closing element in the closed position; and a guide member that is arranged to transmit an opening force to the closing element so as to transfer the closing element from the closed position to the open position; and wherein the centralizer is arranged to move during drilling on the feed is beam in the feed direction together with the rock drilling machine and correspondingly in the reverse direction, when the rock drilling machine and the centralizer are transferred to the changing station; and further, wherein the turning of the changing device at the changing station is arranged to affect the guide member of the centralizer and to transfer the 20 closing element into the open position so as to receive the drill rod in the centre or to remove the drill rod from the centre; and the closing element of the centralizer is locked in a shape-locking manner while in the closed position, whereby the opening of the closing element by the effect of the forces exerted from the drill rod onto the closing 25 element is prevented.

14. The rock drilling unit of claim 13, wherein the guide member of the centralizer is a push rod which is supported to the frame of the centralizer and which push rod is arranged to move in relation to the frame substantially only in its longitudinal direction; 30 and the rock drilling unit comprises a separate push surface connected to the turning mechanism of the changing device, which push surface is arranged to move together with the changing device transversely to the feed beam.

15. The rock drilling unit of claim 14, wherein 35 the changing device and the push surface are arranged at an axial distance from one another seen in the longitudinal direction of the feed beam.

16. The rock drilling unit of claim 14 or 15, wherein 2721738_1 (GHMatters) P87447.AU 30/06/11 13 the push surface is arranged to move in the longitudinal direction of the push rod by means of an articulation mechanism during the turning movement of the changing device.

17. The rock drilling unit of claim 16, wherein 5 the rock drilling unit comprises a turning rod which is in parallel with the feed beam and to which the changing device is connected, the turning rod being arranged for turning about its longitudinal axis by means of the turning device; and the push surface is connected to the feed beam by means of at least one 10 articulated first arm and to the turning rod by means of at least one second articulated arm.

18. The rock drilling unit in accordance with any one of the preceding claims 14 to 17, wherein the magnitude of the linear movement of the push surface is arranged to 15 be inferior to the transverse movement of the changing device in relation to the feed beam.

19. The rock drilling unit in accordance with any one of the preceding claims 13 to 18, wherein the changing device comprises a rod magazine allowing a plurality of drill 20 rods to be stored in parallel side by side.

20. A method of manipulating rodlike pieces in an excavation apparatus, a centralizer, or a rock drilling unit, substantially as herein described with reference to the accompanying drawings. 2721738_1 (GHMatters) P87447.AU 30/06/11