AU2012101626A4 - Guide for drilling tool, and drilling unit - Google Patents

Abstract

Abstract The invention relates to a guide for a drilling tool. By means of the guide (12) the drilling tool is supported to the feed beam of the drilling unit. The guide comprises a frame (13) having a support opening (14) through which the drilling tool (8) may be fitted. In addition, the guide comprises at least two support members (15) for supporting the drilling tool. The support members have a cylindrical outer surface and they are freely rotatable about their central axis. (Figure 2) 3811915_1 (GHMatters) P91739 AU 31/10/2012 12a 1 12b 4 s NS 15a 1 5b F IG. 2 13b 1 5c F IG . 3 15a 1 --- -- ----------- --- ---il3a 15 b----

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Innovation Patent Applicant(s) SANDVIK MINING AND CONSTRUCTION OY Invention Title: Guide for drilling tool, and drilling unit The following statement is a full description of this invention, including the best method for performing it known to me/us: 2 Guide for drilling tool, and drilling unit Background of the invention [0001] The invention relates to a guide for a drilling tool, by means of which the drilling tool is supported to a feed beam during drilling. The drilling tool is arranged through an opening in the guide. In connection with the opening there are support members that support the drilling tool and allow axial movements of the drilling tool and a rotating movement in relation to the axis of the drilling tool. [0002] The invention also relates to a drilling unit. The field of the invention is described in greater detail in the preambles of the independent claims of the application. [0003] In rock drilling the drilling tool is supported by guides which support the drilling tool to a feed beam and thus prevent the elongated drilling tool from bending and oscillating by the effect of drilling forces. Typically, the guides comprise curved, planar surfaces imitating the outline of the drilling tool, straight planar surfaces or planar surfaces arranged in a wedge-like V-shape. Some drawbacks have been found in current guides. Brief description of the invention [0004] In accordance with the present invention there is provided a guide for a drilling tool, which guide comprises: a frame; attaching means by which the guide is connectable to a feed beam of a rock drilling rig; a support opening in the frame, through which the drilling tool may be fitted; at least two support members for supporting the drilling tool; wherein the support member comprises a cylindrical outer surface and a central axis; and the support member is arranged freely rotatable about its central axis. [0005] In accordance with the invention there is further provided a drilling unit comprising: a feed beam; a rock drilling machine comprising at least a rotation device; 3811915_1 (GHManers) P91739.AU 31/10&2012 3 a drilling tool connected to the rock drilling machine; a feed device for moving the rock drilling machine on the feed beam; and at least one guide for the drilling tool, through which guide the drill ing tool is fitted and which is arranged to support the drilling tool to the feed beam; wherein the guide for the drilling tool is in accordance with the guide described above. [0006] An advantage of the tool to be used in rock drilling described herein is that it is supported, during drilling, to the feed beam of the rock drilling rig with one or more guides, through which the tool is fitted and which comprises two or more rotary support members. The support member comprises a cylindrical outer surface and it has a central axis in relation to which the support member may freely rotate when supported against the outer surface of the drilling tool. In that case between the support member and the drilling tool there is provided roller bearing with respect to the rotating movement of the drilling tool and slide bearing with respect to the axial movement of the drilling tool. [0007] An advantage is that the support member is able to rotate freely along the drilling tool, and there is thus rolling contact between the support member and the drilling tool, instead of sliding contact of the known solutions. In that case, in the guide the slide bearing is only required for the axial movement of the drilling tool. Thus, the guide provides a better bearing system than before, which makes it possible to avoid wear of the guide and the drilling tool and consequently to achieve a longer service life and a longer maintenance interval. Further, thanks to the improved bearing system, the friction between the guide and the drilling tool is lower, whereby the power required for rotation may be lower. [0008] The idea of an embodiment is that the support members used in the guide are elongated rolls. At least three rolls of this kind are required around the support opening, but if necessary, their number may be four or more. By means of the elongated roll it is possible to provide a sturdy support member and it is relatively easy to support the roll to the guide frame. Further, the length of the roll may be dimensioned such that surface pressure of a line shaped contact surface between the roll and the outer surface of the drilling tool remains sufficiently low in view of durability. 3119 1501 (GHMatters) P91739AU 31/10/2012 4 [0009] The idea of an embodiment is that the diameter of the guide support roll is at least equal to the diameter of the drilling tool. The larger the diameter of the roll is dimensioned in relation to the drilling tool, the lower the rotating rate transmitted to the roll. Low rotating rate is advantageous in view of durability. Further, the roll having a larger diameter is easier to support to the guide structure. [0010] The idea of an embodiment is that all support members of the guide are freely rotatable and the outer surface of them all is smooth, possessing good sliding properties. In this manner friction forces between the guide and the drilling tool are to be minimized. [0011] The idea of an embodiment is that the outer surface of the support member is made of slide bearing material, such as bronze for bearings. The support roll may also be completely made of slide bearing material. Further, it is possible that the outer surface is coated with a material having good sliding properties. [0012] The idea of an embodiment is that the support members are arranged movably in the guide, and their distance from the drilling tool may thus be adjusted in the transverse direction of the drilling axis. The support members may be moved by means of one or more actuators. The guide of this embodiment is applicable for use in supporting drilling tools of different diameters. [0013] The idea of an embodiment is that the frame of the guide comprises one or more openable portions that facilitate the fitting of the drilling tool into the support opening. [0014] The idea of an embodiment is that the guide is arranged to centre the drilling tool on the drilling axis. Each support member is equipped with an actuator, whereby the support member may be moved in the transverse direction of the drilling axis. In order to provide a centring operation the movements of the actuators are mutually synchronized in such a manner that each support member is arranged to move simultaneously an equal distance towards the drilling axis. [0015] The idea of an embodiment is that each support member is moved by means of a pressure-medium cylinder. In the cylinder, on both sides of the piston there is a piston rod having the same cross-sectional area. Further, the cylinders are interconnected through a synchronizing pressure medium connection such that the pressure medium exiting the return side of a first cylinder during the stroke is conveyed to the stroke side of a second 3811915_1 (GHMatters) P91739.AU 31/10/2012 5 cylinder, and further, the pressure medium exiting the return side of the second cylinder is conveyed to the stroke side of a third cylinder. In that case three, or more if necessary, cylinders are synchronized to move at the same time and an equal distance. In this embodiment each cylinder acts simultaneously both as a work cylinder and as a cylinder pump. [0016] The idea of an embodiment is that the guide comprises three support members arranged with even spacing around the support opening of the guide, i.e. at an angle of 120 degrees to one another. [0017] The idea of an embodiment is that the guide comprises four support members arranged with even spacing around the support opening of the guide, i.e. at an angle of 90 degrees to one another. [0018] The idea of an embodiment is that the support member is arranged in a distal end portion of the feed beam. This kind of guide may be called an end guide. [0019] The idea of an embodiment is that the support member is arranged in a portion between the rock drilling machine and the distal end of the feed beam. This kind of guide may be called an intermediate guide. There may be one, two or more intermediate guides, depending i.a. on the length of the feed beam and the drilling tool. The intermediate guide may be arranged to move on the feed beam in accordance with the feed and return movements of the rock drill. [0020] The idea of an embodiment is that the drilling tool to be supported by the guide is one of the following: drill pipe, drill rod, extension rod, integral rod or self-drilling rock bolt. [0021] The idea of an embodiment is that the drilling unit is an apparatus used for so-called Top Hammer (TH) drilling, where a drill machine, which comprises both a percussion device and a rotation device, is arranged on the feed beam. [0022] The idea of an embodiment is that the drilling unit is an apparatus used for so-called Down-The-Hole (DTH) drilling, where a drill machine, which comprises a rotation device but not a percussion device, is on the feed beam. The percussion device is thus arranged in the drilling equipment in an end portion opposite to the rotation device. [0023] The idea of an embodiment is that the drilling unit is an apparatus used for so-called Rotary Drilling, where a drill machine, which comprises a rotation device, is on the feed beam. The equipment used in this drilling form does not comprise a percussion device at all. 3811915.l (GHMaters) P91739.AU 31/1&2012 6 Brief description of the figures [0024] Some embodiments will be explained in more detail in the attached drawings, in which Figure 1 is a schematic side view of a rock drilling rig, Figure 2 is a schematic, perspective view of a guide and Figure 3 shows the same application, seen from the direction of the drilling axis, Figures 4 and 5 show schematically the principles of some alternative guides, seen from the direction of the drilling axis, Figure 6 shows schematically a centring guide and an arrangement for synchronizing the movements of the support member actuators, Figure 7 shows schematically the principle of DTH drilling and the use of a rotation unit therein, Figure 8 shows schematically yet another principle for moving the support members of the guide, and Figures 9 and 10 show schematically some holding devices, which possess some features that differ from the features of the guides shown in the preceding figures. [0025] In the figures, some embodiments are shown in a simplified manner for the sake of clarity. Like reference numerals refer to like parts in the figures. Detailed description of some embodiments [0026] Figure 1 shows a rock drilling unit 1 that is arranged on a movable drilling boom 2. A rock drilling rig may comprise one or more rock drilling units 1 of this kind. The rock drilling unit 1 comprises a feed beam 3, which is an elongated piece by which a rock drilling machine 4 is arranged to be supported. The rock drilling machine 4 comprises at least a percussion device 5 and a rotation device 6. The rock drilling machine 4 includes a drill shank 7 or the like, to which a drilling tool 8 may be attached. The drilling tool 8 may be a drill pipe or a drill rod, at the distal end of which is arranged a drill bit 9 for breaking rock 10. A plurality of drilling tools 8 may be consecutively connected by means of connecting elements, which allows even long drill holes to be drilled. Further, the drilling tool 8 may be a so-called integral rod. The percussion device 5 delivers impact pulses to the drilling tool 8 and additionally the drilling tool 8 is rotated R about its central axis during drilling. The rock drilling unit 1 further includes a feeding device 11, by which the rock drilling machine 4 may be moved, supported by the feed beam 3, in the impact 381115_1 (GHMatters) P91739.AU 31110/2012 7 direction A and in the reverse direction B. The rock drilling unit 1 may be used for drilling holes to be blasted, or for drilling bolting and injecting holes needed in the reinforcement of the rock. [0027] During drilling, the drilling tool 8 is supported to the feed beam 3 by means of one or more guides 12. Said support makes it possible to prevent vibrations, bending and other harmful phenomena in the drilling tool 8. Further, the guide 12 may be of centring type, whereby it may support the drilling tool 8 to the drilling axis X. As appears from Figure 1, a so-called end guide 12a may be located in the distal end portion of the feed beam 3, and further, one or more so-called intermediate guides 12b may be located in the portion between the distal end of the feed beam 3 and the rock drilling machine 4. The end guide 12a may be arranged in the feed beam 3 in an immovable or movable manner. The intermediate guide 12b may move on the feed beam 3 in the drilling direction A and in the reverse direction B during drilling. The basic structure of the guides 12a and 12b may be the same. The guide 12 comprises a frame 13 having a support opening 14, through which the drilling tool 8 may penetrate. The frame 13 may comprise one or more movable portions that may be opened and closed so that the drilling tool 8 may be fitted in the support opening 14 in a transverse direction. The frame 13 is also furnished with attaching means K by which the guide 12 is attachable to the feed beam 3. [0028] Figure 2 shows the basic idea of the guide 12. For the sake of clarity, the figure does not show the frame of the guide, for instance. The guide 12 may comprise two, three or more support members 15 that are in physical contact with the outer surface of the drilling tool 8 and that support the drilling tool 8 through the guide frame to the feed beam 3. The figure shows a guide 12 having three support members 15a to 15c arranged with even spacing around the support opening 14. The support member 15 may be an elongated roll-like piece having a cylindrical outer surface 16. The support member 15 may be a tubular or bar-like piece. The support member 15 has a central axis M about which the support member 15 may turn S freely by the effect of the rotating force transmitted from the drilling tool 8. No external rotational moment is transmitted through the structure of the guide 12 to the support member 15. The support members 15 may comprise support portions 17 for bearings 18 at the end portions thereof. The support members 15 may be arranged in the guide frame such that they may be moved in the radial direction of the drilling tool 8. This is illustrated later on in Figures 4 to 6. During use, the casing 16 of each support member is pressed against the outer surface of the drilling tool 8, 381195I (GHMatters) P91739 AU 31110/2012 8 whereby the rotating movement R of the drilling tool 8 is transmitted to the support members 15a to 15c and makes them rotate S about their central axes M. An axial movement N of the drilling tool 8 causes sliding between the support members 15 and the drilling tool 8. Further, sliding may also occur in the direction of the rotating movement. Because sliding is allowed between the support members 15 and the drilling tool 8, the casing 16 may be made of material having a low friction coefficient or it may be coated with such material. [0029] Figure 3 shows the guide 12 seen from the direction of the drilling axis X. In the figure, an application of the guide frame 13 is shown in a highly simplified manner by dashed lines. The frame 13 may comprise a fixed part 13a and a movable frame part 13b connected thereto through a hinge 19. The frame part 13b may be opened, for instance, with an actuator 20 and locked into place with a locking member 21. Alternatively, the frame may be open in shape, for instance, in the shape of letter C, whereby it already has a slot through which the drilling tool 8 may be fitted transversally into the support opening 14. [0030] Figure 4 shows a guide 12 comprising four roll-like support members 15a to 15c which may be moved with an appropriate actuator towards the drilling axis X and away therefrom. Control directions T of the support members 15 are indicated in the figure by arrows. The actuator may be a pressure-operated cylinder or motor, or alternatively, it may be an electrical actuator. [0031] Figure 5 also shows four roll-like support members 15a to 15d. The support members 15a and 15d are interconnected through a connecting piece 22a, and correspondingly the support members 15b and 15c are interconnected through a connecting piece 22b. Thus, the guide 12 includes two support units 23a and 23b, each of which comprises at least two freely rotating roll-like support members 15. The support units 23a and 23b may be moved in a control direction T by means of the actuators 24a and 24b. [0032] Figure 6 shows a guide 12, in which the roll-like support members 15a to 15c are moved in the control direction T by means of pressure medium cylinders 25a to 25c. The pressure-medium cylinders 25 are connected to move simultaneously an equal distance. The operation of the cylinders 25 may be controlled by a valve 26, for instance a directional control valve having three control positions a to c. In the figure the valve 26 is in the middle position b, the cylinders 25 being immobile. In the control position a the cylinders 25 move the support members 15a to 15c towards the drilling axis X, and in the 3811915_1 (GHMatters) P91739AU 31/10/2012 9 control position c the cylinders 25 perform a return movement. The cylinders 25 are interconnected through pressure-medium channels 27 and 28. Each cylinder 25 acts simultaneously as a work cylinder producing a linear movement and as a pump cylinder transforming kinetic energy into pressure energy. In the cylinder 25, on the opposite sides of the piston 29 there are a working pressure space 30 and a return pressure space 31. The cylinders 25 are connected in series through pressure channels 27 and 28 in such a manner that, seen in the pressure medium flow direction corresponding to the control position a of the valve 26, the return pressure space 31 of a preceding cylinder is connected to the working pressure space 30 of a subsequent cylinder. Through the pressure spaces 30, 31 there are applied piston rods 32 and 33, the cross-sectional areas of which are equal in these pressure spaces 30 and 31. In that case during the movement an equal amount of pressure medium flows into the cylinder 25 as exits therefrom. The cylinders 25 being constructed in this manner and their pressure spaces being cross-connected in the above described manner, the cylinders can be made to move simultaneously an equal distance. Further, in connection with the cylinders 25, there may be an arrangement for driving the piston 29 to a predetermined position before carrying out a new work stroke towards the drilling axis. This is to ensure that each cylinder 25 starts the movement at the same distance. [0033] Figure 7 shows a drilling unit 1 used in DHT or rotary drilling, which drilling unit differs from what is shown in Figure 1 in that the rock drilling machine 4 is a rotary device without a percussion device. Whereas in DTH drilling the drilling equipment may be provided with a percussion device 34 placed in the drill hole. The percussion device 34 is thus at the opposite end of the drilling equipment in relation to the rotation unit. During drilling, the percussion device 34 is in the drill hole, and the drill bit 9 may be connected directly to the percussion device. The rotary drilling does not comprise any percussion device at all. Also in DHT drilling and rotary drilling the drilling tool 8 may be supported to the feed beam by means of the guides 12a and 12b. The guides may be of any one type described in this application. [0034] Figure 8 shows yet another application of the guide 12, in which the support members 15 are arranged in swivel arms 35. The swivel arm 35 is connected with a hinge 36 to the frame 13 of the guide 12 and the swivel arm 35 may be moved by means of the actuator 25. In that case the support member 15 in the distal end portion of the swivel arm 35 moves in arcuate path 3811915_1 (GHMatters) P91739.AU 31/10012 10 37. The path 37 runs approximately in the radial direction of the drilling axis X, however. [0035] Figure 9 shows the operating principle of a holding device 40. By means of the holding device 40 a drill rod, drill pipe, drill bit or another drilling component or drilling tool included in the drilling equipment may be held in place and non-rotating when these components are connected to one another or detached from one another. Particularly in so-called longhole drilling there is employed an extension rod arrangement including a plurality of consecutively coupled drill rods. The holding device 40 may comprise two or more holding cylinders 41a and 41b, which may be hydraulic cylinders provided with jaws 42. The jaws may be connected to the piston rods and arranged to move on the central axis 43 of the cylinders towards each other, i.e. in a closing direction, and respectively away from one another, i.e. in an opening direction. The holding device 40 in Figure 9 is a centring one, which means that both holding cylinders 41a and 41b are arranged to move an equal distance, when they are moved in the closing direction towards the drilling axis X. Thanks to the centring feature it is possible to avoid lateral stresses exerted on the drilling tool 8 and the rock drilling machine. [0036] The centring function may be provided by using equal holding cylinders 41, in which on both sides of the piston there are piston rods that have equal cross-sectional areas. In addition, the holding cylinders 41 are interconnected through a pressure-medium channel 44. When pressure medium from a pressure source is applied to the first holding cylinder 41a via the control valve 45 and a pressure-controlled check valve 46 along the channel 47, the first holding cylinder 41a performs a work stroke towards the drilling axis X, and consequently an equal amount of pressure medium exits the return-side pressure space 49 on the other side piston 48 along a channel 44 to the working pressure space 50 of the second holding cylinder 41b thus providing a simultaneous work stroke of the second holding cylinder 41b towards the drilling axis X. When the control valve 45, for instance a directional control valve, changes the flow direction of the pressure medium, the pressure medium is conveyed from the pressure source to the pressure space 51 of the return direction of the second holding cylinder 41b, which produces a return movement. Thus, the pressure medium flows from the working pressure space 50 of the second holding cylinder 41 b into the pressure space 49 of the return direction of the holding cylinder 41a, and consequently the first holding cylinder 41a also performs a simultaneous return movement. The holding cylinders 41 3811915_1 (GHMattes) P91739AU 31/10/2012 11 are thus hydraulically connected in series with synchronizing connection. The holding device 40 may have a movement function similar to that of the centring guide shown in Figure 7 of the present application. [0037] The jaws 42 may be supported by means of guide surfaces 52 or the like guides in such a manner that they may move linearly only. The guide surfaces 52 may thus receive transversal forces possibly exerted on the jaws 42 and the holding cylinders 41, and additionally they prevent the jaws and the piston rods from turning about the central axis 43 of the cylinder. [0038] The holding device 40 may be equipped with a connection and means which make sure that the movement of the holding cylinders 41 towards the drilling axis X always starts at the mutually equal distance. During the return movement the holding cylinders 41 drive the jaws 42 to an equal point in distance. In that case it is possible to make sure that during the work stroke the jaws 42 will be at the same distance from the drilling axis X and will centre the drilling tool 8. This application takes into account pressure medium leaks, if any, which might, with time, result in differences in the initial position of the jaws 42 as seals wear out. One solution is to drive the holding cylinders 41, in the return direction, to their extreme positions, for instance, against a limiter or an end cover in the return direction of the cylinder. Figure 10 illustrates a hydraulic coupling in an application of this kind. [0039] In Figure 10 from the pressure source it is possible to apply a pressure of 180 bar, for instance, via a pressure-controlled check valve 46 and a channel 47 to the working pressure chamber 53 of the first holding cylinder 41a, whereby the first holding cylinder 41a performs a working stroke. From the return side chamber 49 of the first holding cylinder 41a pressure medium flows along the channel 44 to the working pressure chamber 50 of the second holding cylinder 41b, whereby the second holding cylinder 41b performs a work stroke. In the channel 44 there may be a pressure-controlled valve 54 which in the position of the figure is affected by a spring and allows a flow from the chamber 49 into the chamber 50. When the jaws 42 are driven in the open direction, it is possible to apply a pressure of 250 bar, for instance, from the pressure source into the return-side chamber 51 of the second holding cylinder 41b. Said pressure changes the position of the valve 54 to a control position shown higher up in the figure, in which the flow exiting the working pressure chamber 50 of the second holding cylinder 41b may run along the channel 44 into the return chamber 49 of the first cylinder 41a. For the valve 54 the valve opening pressure may be set to 200 bar, for instance. Further, a pressure-controlled 3811915.1 (GHMattes) P91739.AU 311102012 12 safety valve 55, for which the opening pressure may be set to 200 bar, for instance, may be connected to the channel 44. When the holding cylinders 41 are moved to open towards their extreme position the pressure rises in the chambers 50 and 53. The pressure is able, however, to discharge from the chamber 50 via the safety valve 55 into a tank and further from the chamber 53 into a channel 47 having a lower pressure such that the holding cylinders 41 can be driven to their extreme positions against the rear cover as a higher pressure prevails in the chambers 49 and 51 of the holding cylinders. The pressures are given here just as examples. As regards the coupling, it is essential that differences between the pressures applied from the pressure source and the opening pressures of the valves 54, 55 are arranged in an appropriate manner. [0040] An alternative solution to that of Figure 10 may be such that the coupling is otherwise similar to that of Figure 9 but the pressure spaces 50 and 53 of the holding cylinders 41 are each equipped with pressure-controlled safety valves which allow the pressure flow to pass through when the pistons are driven against a mechanical limiter or a cylinder end. [0041] In some cases, features disclosed in this application may be used as such, regardless of other features. On the other hand, when necessary, features disclosed in this application may be combined in order to provide various combinations. [0042] The drawings and the relating description are only intended to illustrate the idea of the invention. The details of the invention may vary within the scope of the claims. [0043] 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 presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention. 38119151 (GHMatters) P91739 AU 31/10/2012

Claims (5)

1. A guide for a drilling tool, which guide comprises: a frame; attaching means by which the guide is connectable to a feed beam of a rock drilling rig; a support opening in the frame, through which the drilling tool may be fitted; at least two support members for supporting the drilling tool; wherein the support member comprises a cylindrical outer surface and a central axis; and the support member is arranged freely rotatable about its central axis.

2. The guide as claimed in claim 1, wherein the support member is an elongated roll; and the guide comprises at least three rolls around the support opening.

3. The guide as claimed in claim 1 or 2, wherein at least the outer surface of the support member is made of slide bearing material.

4. The guide as claimed in any one of the preceding claims, wherein the guide is arranged to centre the drilling tool onto the drilling axis; each support member is provided with an actuator for moving the support member in a transverse direction of the drilling axis; and the movements of the actuators are mutually synchronized, whereby each support member is arranged to move simultaneously an equal distance towards the drilling axis.

5. A drilling unit comprising: a feed beam; a rock drilling machine comprising at least a rotation device; a drilling tool connected to the rock drilling machine; a feed device for moving the rock drilling machine on the feed beam; and

3811915.1 (GHMatters) P91739.AU 3111012012 14 at least one guide for the drilling tool, through which guide the drill ing tool is fitted and which is arranged to support the drilling tool to the feed beam; wherein the guide for the drilling tool is in accordance with claim 1. 3811915.1 (GHMatters) P91739AU 31110f2012