Tubular rock bolt installation

Abstract

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Description

Field

[0001] The present invention relates to the installation of a rock bolt, and in particular, a device for automatically installing a hollow rock bolt. Background

[0002] Hollow rock bolts are known, as are various devices for installing hollow rock bolts. Hollow rock bolts may contain a pre-installed resin cartridge which is configured to dispense and flow down the borehole annulus to provide anchoring of the bolt.

[0003] Hollow rock bolts may also be self-drilling, allowing the bolts to be installed in a more efficient process. This type of bolt is drilled, resin is dispensed to anchor the bolt and then, upon curing of the resin, the bolt is pre-tensioned in the ground by tightening the nut.

[0004] In hollow rock bolts where the resin is contained internally, the resin may be dispersed via water pressure. In some cases, it can be difficult to ensure dispensation of the resin by the water pressure. This is due to the uncertainty of knowing what volume of water has been pumped to fully dispense the resin, with some losses of water occurring. As a result, visual confirmation of resin dispensing is typically required. Also, the features required to ensure repeatability of dispensation using water pressure can be more complex. Object

[0005] It is an object of the present invention to substantially overcome or ameliorate one or more of the above disadvantages, or to at least provide a useful alternative. Summary of Invention [0005a] An aspect of the present invention provides a drill motor assembly for installing a hollow rock bolt having a pre-inserted resin cartridge, the drill motor assembly including: a drill motor movable along a first axis; and 2020217422   25 Jun 2026 a hollow shaft coaxially connectable to the hollow rock bolt and operatively connected to the drill motor for rotation about a second axis generally parallel to the first axis, the hollow shaft being simultaneously movable along the second axis, wherein the hollow shaft is configured to receive a moving mechanical element for advancement through the hollow shaft and the hollow rock bolt to provide an axial force on the resin cartridge for dispersing the resin, the drill motor assembly further including a drive system configured to control movement of the mechanical element through the hollow shaft along the second axis. [0005b] Another aspect of the present invention provides a device for installing a hollow rock bolt having an internal resin cartridge configured to be ruptured to dispense resin, the device including: a drill mast having a longitudinal axis, the drill mast configured to receive a hollow drill rod having a drill bit at one end, and a hollow rock bolt; a drill motor assembly having a drill motor and a rotatable hollow shaft connectable to the hollow drill rod and the hollow rock bolt, the drill motor being mountable to the drill mast and movable along the longitudinal axis; thrusting means for rupturing the internal resin cartridge, the thrusting means being mountable to the drill mast and movable independently of the drill motor along the longitudinal axis; and a drive system configured to control movement of the thrusting means through the rotatable hollow shaft. [0005c] Yet another aspect of the present invention provides a method of installing a hollow rock bolt having a pre-inserted resin cartridge, the method including: drilling a borehole into ground strata; inserting the hollow rock bolt into the borehole; advancing a mechanical element through the hollow rock bolt to rupture the resin cartridge to disperse the resin whilst simultaneously measuring advancement of the mechanical element through the hollow rock bolt; and retracting the mechanical element automatically in response to a measurement of advancement of the mechanical element reaching or exceeding a threshold indicative of sufficient displacement of the mechanical element to rupture the resin cartridge. 2020217422   25 Jun 2026

[0006] One embodiment of the present invention provides a drill motor assembly for installing a hollow rock bolt having a pre-inserted resin cartridge, the drill motor assembly including: a drill motor movable along a first axis; and 2020217422  13 Aug 2020 a hollow shaft coaxially connectable to the hollow rock bolt and operatively connected to the drill motor for rotation about a second axis generally parallel to the first axis, the hollow shaft being simultaneously movable along the second axis, wherein the hollow shaft is configured to receive a moving mechanical element for advancement through the hollow shaft and the hollow rock bolt to provide an axial force on the resin cartridge for dispersing the resin.

[0007] Preferably, the mechanical element includes a flexible cable or wire, guided through the hollow shaft and hollow bolt. Opposing drive members, such as pulleys, wheels, belts or sprockets, may be employed to advance the mechanical element along the second axis.

[0008] Alternatively, the mechanical element may be a rigid rod, and similar, or a different configuration, of drive members may be used to advance the rod along the second axis.

[0009] Preferably, the guide means further includes idler members connected to a shaft encoder for measurement of advancement of the mechanical element. This is a safety feature to ensure there is sufficient displacement of the mechanical element to rupture the resin cartridge and substantially dispense the contents of the resin.

[0010] Another embodiment of the present invention provides a device for installing a hollow rock bolt having an internal resin cartridge configured to rupture the cartridge and dispense resin, the device including: a drill mast having a longitudinal axis, the drill mast configured to receive a hollow drill rod having a drill bit at one end, and a hollow rock bolt; a drill motor having a rotatable hollow shaft connectable to the hollow drill rod and the hollow rock bolt, the drill motor being mountable to the drill mast and movable along the longitudinal axis; and thrusting means for rupturing the internal resin cartridge, the thrusting means being mountable to the drill mast and movable independently of the drill motor along the longitudinal axis.

[0011] In one embodiment, the thrusting means includes a rigid rod having a base and a distal end portion, the base being configured to engage the hollow shaft with the distal end portion configured to advance through the hollow bolt to rupture the internal resin cartridge. 2020217422  13 Aug 2020

[0012] Alternatively, the thrusting means may include a guided flexible cable movable through the hollow shaft and the hollow bolt to rupture the internal resin cartridge.

[0013] Preferably, the guided flexible cable includes opposing drive members, such as pulleys or sprockets, configured to advance the flexible wire, or cable, through the hollow shaft and the hollow bolt.

[0014] Preferably, the guided flexible cable includes an idler member configured to measure advancement of the flexible cable through the hollow shaft and the hollow bolt to ensure sufficient displacement to rupture the resin cartridge and substantially dispense resin.

[0015] Preferably, the device includes a water delivery system providing water from an external source to the hollow drill rod for wet drilling.

[0016] A further embodiment of the present invention provides a hollow bolt including: a generally tubular elongate body defining a cavity extending longitudinally through the body; a leading end portion terminating at an open leading end; and a trailing end portion terminating at an open trailing end, wherein the body is configured to receive a resin cartridge within the cavity, and wherein the open trailing end is configured for receiving a mechanical element to advance though the cavity to disperse resin within the resin cartridge.

[0017] In one embodiment, the hollow bolt includes a fixed cap covering the opening of the leading end, the cap having at least one aperture to permit dispersion of resin from within the cavity to outside the cavity.

[0018] Alternatively, the leading end of the bolt is deformable to partially close the opening, allowing for dispersion of resin from within the cavity through gaps in the partially closed leading end.

[0019] Preferably, the hollow bolt includes a static mixer element disposed within the cavity for mixing resin prior to dispersement. 2020217422  13 Aug 2020

[0020] A further embodiment of the present invention provides a method of installing a hollow rock bolt having a pre-inserted resin cartridge, the method including: drilling a borehole into ground strata; inserting the hollow rock bolt into the borehole; and advancing a mechanical element through the hollow rock bolt to disperse the resin cartridge.

[0021] Preferably, the mechanical element is a flexible cable or wire.

[0022] Preferably, the method further comprises: coaxially connecting a hollow shaft to the hollow rock bolt, the hollow shaft being operatively connected to a drill motor for rotating the hollow shaft and advancing the hollow shaft about the axis of rotation; wherein, the hollow shaft is configured to receive the moving mechanical element for advancement through the hollow shaft and the hollow rock bolt to provide an axial force on the resin cartridge.

[0023] Preferably, the method further comprises: providing a drill mast having a longitudinal axis, the drill mast configured to receive a hollow drill rod with a drill bit at one end, and the hollow rock bolt; such that, the drill motor and the rotatable hollow shaft is connectable to the hollow drill rod and the hollow rock bolt, the drill motor being mountable to the drill mast and movable along the longitudinal axis; and, mounting thrusting means to the drill mast for movement independently of the drill motor along the longitudinal axis to rupture the pre-inserted resin cartridge.

[0024] Preferably, the thrusting means includes a rigid rod having a base and a distal end portion, the base being configured to engage the hollow shaft with the distal end portion configured to advance through the hollow bolt to rupture the pe-inserted resin cartridge. Brief Description of Drawings

[0025] Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: 2020217422  13 Aug 2020

[0026] Figures 1 to 5 show a hollow bolt in accordance with one embodiment of the present invention,

[0027] Figures 6 to 9 show a drill rod in accordance with an embodiment of the present invention;

[0028] Figures 10 to 12 show a drill motor assembly for use with the bolt shown in Figures 1 to 5 and the drill rod shown in Figures 6 to 9;

[0029] Figures 13 and 14 show a device for use with the hollow bolt of Figures 1 to 5 and the drill rod of Figures 6 to 9, wherein the drill motor assembly is in the home position and prior to drilling a borehole;

[0030] Figures 15 and 16 show the device of Figures 13 and 14, wherein the drill rod and water supply system have been added and prior to drilling the borehole;

[0031] Figures 17 and 18 show the device of Figures 13 and 14, wherein the drill motor assembly is advanced and the drill rod has drilled the borehole;

[0032] Figures 19 and 20 show the device of Figures 13 and 14, wherein the drill motor assembly is retracted to the home position;

[0033] Figures 21 and 22 show the device of Figures 13 and 14, wherein the drill motor is in the home position, and the drill rod and water supply have been removed;

[0034] Figures 23 and 24 show the device of Figures 13 and 14, wherein the drill motor assembly is in the home position, and the hollow bolt has been loaded;

[0035] Figures 25 and 26 show the device of Figures 13 and 14, wherein the drill motor assembly has advanced to install the hollow bolt into the borehole;

[0036] Figures 27 and 28 show the device of Figures 13 and 14, wherein the drill motor assembly has advance, the hollow bolt is installed, and the mechanical element is advanced to rupture the resin cartridge; and 2020217422  13 Aug 2020

[0037] Figures 29 and 30 show the device of Figures 13 and 14, wherein the drill motor assembly is retracted to the home position and the hollow bolt is installed and anchored within the borehole. Description of Embodiments

[0038] Figures 1 to 5 show an embodiment of a tubular, or hollow, bolt assembly 10. The hollow bolt assembly 10 has a generally tubular elongate body 12, a leading end portion 14 terminating at a leading end 16 and a trailing end portion 18 terminating at a trailing end 20. The body 12 defines a cavity 22 extending longitudinally through the body 12. The hollow bolt 10 has an external profile for embedding / interlocking into resin and generating load transfer.

[0039] The body 12 houses a resin cartridge 24 within the cavity 22. The resin cartridge 24 may be a two-speed system, with slow setting resin within the hollow bolt 10 to dispense and flow down the borehole annulus first, subsequently followed by the fast speed resin. The fast speed resin will provide point anchoring and permit pre-tensioning of the hollow bolt 10. A plug 72 is positioned below the resin cartridge 24 to prevent the resin from flowing down the cavity 22 of the bolt 10.

[0040] The hollow bolt 10 may include an end cap 26 at the leading end 16 of the bolt 10 with one or more apertures 28 to permit resin dispersion. Alternatively, the leading end 16 of the hollow bolt 10 may be left open. This allows for the resin cartridge 24 to be easily installed. The leading end 16 may either be left open or crushed and folded. When the leading end 16 is crushed and folded, the resin may be dispersed through gaps in the fold.

[0041] A static mixer element 28 may be positioned in the leading end portion 14 of the hollow bolt 10 just above the resin cartridge 24.

[0042] Alternatively, depending on the installation sequence (discussed below) the static mixer element 28 may be eliminated, and resin mixing may be accomplished by rotating the hollow bolt 10 in the borehole after the resin has been dispersed.

[0043] Figures 6 to 9 show a drill steel, or drill rod assembly 54. The drill rod assembly 54 includes an elongate body 56 having a longitudinally extending cavity 57, a drill bit 58, and a rotatable drive incorporating a rotary union 60 (best shown in Figures 8 and 9). The rotary 2020217422  13 Aug 2020 union 60 provides a fixed inlet for the water delivery subassembly (see below) while allowing the drill body 56 to rotate.

[0044] A water delivery subassembly 61 providing water from an external source may be employed for wet drilling. As best seen in Figures 8 and 9, the water delivery subassembly includes an input shaft 62 engaged with an upper portion of the drill motor hollow shaft 34, via a matching drive profile within the hollow shaft 34 to provide water to a central axis of the hollow drill rod assembly 54 for wet drilling.

[0045] Alternatively, the water delivery subassembly 61 may be integral with the output shaft 40 of the drill motor 32, depending on preferred water sealing arrangement with the drill rod assembly 54.

[0046] Figures 10 to 12 show the drill motor assembly 30 for installing the hollow rock bolt 10. The drill motor assembly 30 includes a hydraulic motor 32 and a hollow shaft 34 mounted adjacent the motor 32. A gear box connection 38, including a pair of spur gears connects the motor output shaft 40 and the hollow shaft 34.

[0047] The motor 32 and hollow shaft 34 are each mounted on a primary, or upper carriage 39 and movable longitudinally along parallel axes A-A and B-B respectively to perform, first the drilling of the borehole 36 and then the installation of hollow bolt 10 (see below).

[0048] A mechanical element, such as a rod, or cable 42 is advanced through the hollow shaft 34 and the hollow bolt 10 engaging the resin cartridge 24 causing it to rupture dispensing resin. The mechanical element 42 may be rigid or flexible, for example, a rod or a cable. The mechanical element 42 may be mounted on a separate carriage 40, attached to the drill mast 52. The separate carriage 40 travels with the drill mast 52 and independently of the motor assembly 30.

[0049] The mechanical element 42 must be advanced with sufficient axial force to dispense the resin cartridge 24 through the hollow bolt 10. A plurality of opposed drive members such as pulleys or sprockets 44 can be employed to advance the rod, or cable 42 through the hollow shaft 34 and bolt 10. The drive members 44 open to receive the rod, or cable 42 and then close to advance the rod, or cable 42 toward the resin cartridge 24. Optionally, the lower carriage 40 may include a separate set of idler members 46 connected to a shaft encoder (not shown) to 2020217422  13 Aug 2020 measure the distance of advancement of the rod, or cable 42 to ensure there is sufficient displacement of the cable 42 to rupture the resin cartridge 24.

[0050] Installation of the rock bolt 10 will now be described with reference to Figures 15 to 30.

[0051] Firstly, a borehole 36 (see Figures 19 and 20) is drilled into the rock face of a rock strata 50 to be stabilized. Figures 13 and 14 show a device 5 for drilling the borehole 36 and installing the rock bolt 10. The device 5 includes a drill mast 52 and a drill motor assembly 30. The drill motor assembly 30 is in the rest, or home, position on the drill mast 52. Figure 14 shows a hexagonal nut 7 for attachment of the drill rod 54. Other profiles may be suitable.

[0052] In Figures 15 and 16, a hollow drill steel, or drill rod 54 is loaded on the hollow shaft 34 of the motor 32, and the water delivery subassembly 61 connected.

[0053] As shown in Figures 17 and 18, the drill motor assembly 30 advances along the drill mast 52 toward the rock strata 50. The motor 32 rotates the drill steel 54 to drill the borehole 36 a pre-determined distance. Water is provided from the water delivery subassembly 56 if required.

[0054] Figures 19 and 20 show the device 5 when the motor assembly 30 is in the home position. Once the borehole 36 is drilled, the drill motor assembly 30 retracts, withdrawing the drill steel 54 from the borehole 36 and returns to the rest, or home, position. As shown in Figures 21 and 22 the drill steel 54 and the water delivery subassembly 56 can be removed from the device 5.

[0055] Referring to Figures 23 and 24, a hollow rock bolt 10, with a pre-installed internal resin cartridge 24 (see Figure 1), is loaded on the drill motor hollow shaft 34. In the embodiment shown the hollow bolt 10 has a hexagonal nut 64 on the trailing end 20 configured to engage with a hexagonal nut 66 on the hollow motor shaft 34. It will be appreciated that other engagement means may be appropriate.

[0056] Figures 25 and 26 show the motor assembly 30 advanced along the drill mast 52, and the hollow rock bolt 10 inserted within the pre-drilled borehole 26. The motor assembly 30 stops at a pre-determined depth and holds the bolt 10 in place. 2020217422  13 Aug 2020

[0057] In Figures 27 and 28 the mechanical element, in the form of a flexible cable 42 is loaded with the second, or lower carriage, and fed through the hollow shaft 34 and the hollow bolt 10 providing enough force to the resin cartridge 24 causing the cartridge 24 to rupture, dispersing the resin up through the leading end 18 of the bolt 10 and down the annulus between the bolt 10 and the borehole 36.

[0058] In this embodiment a plurality of drive members in the form of chain driven sprockets 44 guides the flexible cable 42 through the hollow shaft 34, and a pair of idler members 46 are connected to a shaft encoder (not shown) to measure the distance of advancement of the cable 42 to ensure there is sufficient displacement of the cable to rupture the resin cartridge 24. Alternatively, a pulley system may replace the sprockets.

[0059] Once the resin cartridge 24 has ruptured and resin dispensed, the cable 42 is retracted to the home, or rest, position (see Figures 25 and 26).

[0060] If a static mixer 28 is employed the resin will have mixed during dispersement and reaction will have commenced.

[0061] If a static mixer is not employed the resin has not been mixed during dispersement, and after the cable 46 is retracted, the drill motor 30 is used to rotate the hollow bolt 10 to properly mix and react the resin in the annulus between the hollow bolt 10 and the borehole 54.

[0062] Once the resin curing is complete, the drill motor 30 rotates to advance a threaded nut 66 on the bolt 10 to pretension the bolt 10. As is known, a plate 68 and a ball, or dome washer 70 may be used to account for any misalignment between the rock face and the nut.

[0063] If a shear pin (not shown) is used within the bolt design (where there is no static mixer present), the shear pin is broken during this action.

[0064] Once the secondary, or lower, carriage is in the home, or rest, position, the dispersement element is removed.

[0065] The primary, or upper, carriage and drill motor are retracted to the rest, or home position. io 2020217422  13 Aug 2020

[0066] Although the invention has been described with reference to a specific example, it will be appreciated by those skilled in the art that the invention may be embodied in other forms.

Claims

1. A drill motor assembly for installing a hollow rock bolt having a pre-inserted resin cartridge, the drill motor assembly including:a drill motor movable along a first axis; anda hollow shaft coaxially connectable to the hollow rock bolt and operatively connected to the drill motor for rotation about a second axis generally parallel to the first axis, the hollow shaft being simultaneously movable along the second axis, whereinthe hollow shaft is configured to receive a moving mechanical element for advancement through the hollow shaft and the hollow rock bolt to provide an axial force on the resin cartridge for dispersing the resin,the drill motor assembly further including a drive system configured to control movement of the mechanical element through the hollow shaft along the second axis.

2. The assembly of claim 1, wherein the mechanical element includes a flexible cable or wire, guided through the hollow shaft and hollow bolt.

3. The assembly of claim 1 or 2, wherein the drive system includes opposing drive members configured to engage the mechanical element for advancing and retracting the mechanical element along the second axis.

4. The assembly of claim 1, wherein the mechanical element includes a rigid rod having a base and a distal end portion, the base being configured to engage the hollow shaft with the distal end portion configured to advance through the hollow bolt to rupture the internal resin cartridge.

5. The assembly of any one of the preceding claims further including idler members connected to a shaft encoder for measurement of advancement of the mechanical element.

6. A device for installing a hollow rock bolt having an internal resin cartridge configured to be ruptured to dispense resin, the device including:a drill mast having a longitudinal axis, the drill mast configured to receive a hollow drill rod having a drill bit at one end, and a hollow rock bolt;a drill motor assembly having a drill motor and a rotatable hollow shaft connectable to the hollow drill rod and the hollow rock bolt, the drill motor being mountable to the drill mast and movable along the longitudinal axis;2020217422   25 Jun 2026thrusting means for rupturing the internal resin cartridge, the thrusting means being mountable to the drill mast and movable independently of the drill motor along the longitudinal axis; anda drive system configured to control movement of the thrusting means through the rotatable hollow shaft.

7. The device of claim 6, wherein the thrusting means includes a rigid rod having a base and a distal end portion, the base being configured to engage the hollow shaft with the distal end portion configured to advance through the hollow bolt to rupture the internal resin cartridge.

8. The device of claim 6, wherein the thrusting means includes a guided flexible cable movable through the hollow shaft and the hollow bolt to rupture the internal resin cartridge.

9. The device of claim 8, wherein the drive system includes opposing drive members configured to engage the guided flexible cable for advancing and retracting the flexible cable through the hollow shaft and the hollow bolt.

10. The device of claim 8, wherein the guided flexible cable includes an idler member configured to measure advancement of the flexible cable through the hollow shaft and the hollow bolt to ensure sufficient displacement to rupture the resin cartridge and substantially dispense resin.

11. The device of any one of claims 6 to 10 further including a water delivery system providing water from an external source to the hollow drill rod for wet drilling.

12. A method of installing a hollow rock bolt having a pre-inserted resin cartridge, the method including:drilling a borehole into ground strata;inserting the hollow rock bolt into the borehole;advancing a mechanical element through the hollow rock bolt to rupture the resin cartridge to disperse the resin whilst simultaneously measuring advancement of the mechanical element through the hollow rock bolt; andretracting the mechanical element automatically in response to a measurement of advancement of the mechanical element reaching or exceeding a threshold indicative of sufficient displacement of the mechanical element to rupture the resin cartridge.2020217422   25 Jun 202613. The method of claim 12 wherein the mechanical element is a flexible cable, rod or wire.

14. The method of claims 12 or 13 further comprising:coaxially connecting a hollow shaft to the hollow rock bolt, the hollow shaft being operatively connected to a drill motor for rotating the hollow shaft and advancing the hollow shaft about the axis of rotation; wherein,the hollow shaft is configured to receive the moving mechanical element for advancement through the hollow shaft and the hollow rock bolt to provide an axial force on the resin cartridge.

15. The method of claim 14 further comprising:providing a drill mast having a longitudinal axis, the drill mast configured to receive a hollow drill rod with a drill bit at one end, and the hollow rock bolt; such that,the drill motor and the rotatable hollow shaft is connectable to the hollow drill rod and the hollow rock bolt, the drill motor being mountable to the drill mast and movable along the longitudinal axis; and,mounting the mechanical element to the drill mast for movement independently of the drill motor along the longitudinal axis to rupture the pre-inserted resin cartridge.DSI Underground Australia Pty LimitedPatent Attorneys for the Applicant / Nominated PersonSPRUSON & FERGUSON

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