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Title:
DRILLING AND BOLTING DOLLY
Document Type and Number:
WIPO Patent Application WO/2021/056062
Kind Code:
A1
Abstract:
A drilling and bolting dolly driving a drill rod in a first phase of a rock bolting operation and driving a nut of a rock bolt in a second phase of the rock bolting operation. In a preferred form, the dolly is adapted for engagement with a chuck of a rock bolt drilling machine. In a preferred form, the dolly comprises a chuck of a rock bolt drilling machine. Also disclosed is method of installing a rock bolt with a dolly adapted for engagement with a drill rod and with a rock bolt in successive operations of a rock bolt installation; the method including the steps of providing a dolly with an internal water passage, aligning a rock bolt drilling machine with a selected location for the rock bolt with the drilling machine in a retracted position, fitting a drilling rod to an upper end of the dolly, bringing a tip of the drilling rod to strata to be drilled, initiating water flow through the drilling machine, the dolly and the drilling rod, and applying thrust and rotation to the drill rod and drilling a hole in the strata until reaching required depth of the hole.

Inventors:
WYLIE ALASTER
Application Number:
PCT/AU2020/051011
Publication Date:
April 01, 2021
Filing Date:
September 23, 2020
Export Citation:
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Assignee:
STELLAR MINING PTY LTD (AU)
International Classes:
E21D20/00; B25B23/08; E21D21/00
Domestic Patent References:
WO2005085582A12005-09-15
Foreign References:
US4907660A1990-03-13
US20190099813A12019-04-04
US8302708B12012-11-06
US4558976A1985-12-17
AU2007100686A42007-09-06
Attorney, Agent or Firm:
WALLINGTON-DUMMER PATENT AND TRADE MARK ATTORNEYS (AU)
Download PDF:
Claims:
CLAIMS

1. A drilling and bolting dolly driving a drill rod in a first phase of a rock bolting operation and driving a nut of a rock bolt in a second phase of the rock bolting operation.

2. The dolly of claim 1 wherein the dolly is adapted for engagement with a chuck of a rock bolt drilling machine.

3. The dolly of claim 1 wherein the dolly comprises a chuck of a rock bolt drilling machine.

4. The dolly of claim 2 wherein a portion of the length of the dolly is provided proximate a lower end with an integral nut for engagement with the chuck of the rock bolt drilling machine.

5. The dolly of any one of claims 1 to 4 wherein a portion of the length of the dolly is provided at an upper end with a socket for engagement with either a drive portion of a drill rod or with a nut of a rock bolt.

6. The dolly of claim 5 wherein a passage extends from below the socket; the passage accommodating a tail of a drill rod or a threaded section of a rock bolt extending from below the nut of the rock bolt.

7. The dolly of claim 6 wherein a cylindrical chamber is located within the dolly below the passage; the cylindrical chamber further providing for any further length of threaded section of the rock bolt.

8. The dolly of claim 7 wherein a water passage extends from a lower end of the dolly to the cylindrical chamber.

9. The dolly of claim 7 wherein the cylindrical chamber is provided with a spring-loaded water flow control element; the control element comprising a stem depending from a disc; a water passage extending through the stem communicating with an opening in the disc; the spring acting between a lower surface of the cylindrical chamber and an underside of the disc.

10. The dolly of claim 9 wherein a lower end of the tail of a drill rod is seated against an upper surface of the disc when a drill rod is inserted into the dolly; the water passage extending from the lower end of the dolly, the water passage through the stem of the water flow control element and a water passage of the drill rod then forming a continuous water passage of substantially equal diameter.

11. The dolly of claim 9 or 10 wherein the spring of the spring-loaded water flow control element allows the disc to be depressed downwardly in the cylindrical chamber by the threaded end of a rock bolt according to any further length of treaded section of the rock bolt intruding into the dolly.

12. A method of installing a rock bolt with a dolly adapted for engagement with a drill rod and with a rock bolt in successive operations of a rock bolt installation; the method including the steps of:

Providing a dolly with an internal water passage,

Aligning a rock bolt drilling machine with a selected location for the rock bolt with the drilling machine in a retracted position,

Fitting a drilling rod to an upper end of the dolly,

Bringing a tip of the drilling rod to strata to be drilled,

Initiating water flow through the drilling machine, the dolly and the drilling rod, Applying thrust and rotation to the drill rod and drilling a hole in the strata until reaching required depth of the hole.

13. The method of claim 12 wherein the installation includes the further steps of;

Stopping rotation of the drilling machine and shutting off the water flow,

Returning the drilling machine to the retracted position and removing the drill rod from the dolly,

Fitting a rock bolt to the end of the dolly, a nut of the rock bolt seating in a socket of the dolly,

Driving the dolly to insert the rock bolt into the drilled hole,

Rotating the dolly and the rock bolt to activate an anchor of the rock bolt,

Continuing rotation of the nut of the rock bolt after the anchor has formed a bond with the strata to tension the rock bolt in the strata.

14. The method of claim 12 or 13 wherein the dolly is adapted for engagement with a chuck of a rock bolt drilling machine.

15. The method of claim 12 or 13 wherein the dolly comprises a chuck of a rock bolt drilling machine.

16. The method of any one of claim 12 or 15 wherein the dolly is provided with a spring- loaded water flow control element; a water passage through the spring-loaded water flow control element being of a diameter substantially equal to both a water passage in a lower portion of the dolly and a water passage through the drill rod; the spring loaded water flow control element preventing delay in water delivery to a drilling tip of the drill rod.

17. The method of claim 16 wherein in a drilling phase of the rock bolt installation, a spring of the spring-loaded water flow control element urges the control element into contact with a lower end of the drill rod.

18. The method of claim 16 or 17 wherein the spring of the spring-loaded water flow control element provides for the control element to be depressed to a lower level within the dolly by intrusion of a threaded end of a rock bolt.

19. A drilling and bolting dolly providing engagement between a chuck of a rock bolt drilling machine and a drill rod in a first phase of a rock bolting operation and between the chuck and a rock bolt in a second phase of the rock bolting operation; the dolly including a socket at an upper end of the dolly sized to receive either an integral nut of a drill rod or a nut of a rock bolt.

20. The dolly of claim 19 wherein the dolly includes a passage depending from below the socket; the passage sized to accept either the tail of a drill rod or a length of threaded end of a rock bolt extending from the nut.

21. The dolly of claim 19 or 20 wherein a lubricating fluid passage extends from a lower end of the dolly to communicated with the passage below the socket; the lubricating fluid passage passing lubricating fluid to a lubricating fluid passage of a drill rod when the tail of the drill rod is located in the passage below the socket.

22. The dolly of claim 19 wherein the dolly further includes an integral nut proximate the lower end of the dolly for engagement with the chuck of the drilling machine.

23. A dolly for driving a drill rod in a first phase of a rock bolting operation and a nut of a rock bolt in a second phase of a drilling operation; the dolly forming a chuck of a rock bolt drilling machine.

24. The dolly of claim 23 wherein a portion of the length of the dolly is provided at an upper end with a socket for engagement with either a drive portion of a drill rod or with a nut of a rock bolt.

25. The dolly of claim 24 wherein a passage extends from below the socket; the passage accommodating a tail of a drill rod or a threaded section of a rock bolt extending from below the nut of the rock bolt.

26. The dolly of claim 25 wherein a cylindrical chamber is located within the dolly below the passage; the cylindrical chamber further providing for any further length of threaded section of the rock bolt.

27. The dolly of claim 26 wherein a water passage extends from a lower end of the dolly to the cylindrical chamber.

Description:
DRILLING AND BOLTING DOLLY

TECHNICAL FIELD

[0001] The present invention relates to mining equipment and, more particularly although not exclusively, to equipment for installing rock bolts in strata.

BACKGROUND

[0002] The drilling and rock bolting process has seen minimal changes since first being used in underground mining in the 1970’s. There have been improvements in the hydraulic capabilities of the drilling machines, but minimal improvements in the process of drilling a hole and installing a rock bolt with a chemical (or mechanical) anchor. The typical process is as follows:

[0003] Firstly, the drill motor is aligned to the correct position at which the rock bolt is to be installed. The hole is drilled using a drill rod provided with a cutting tip at its outer end. The lower end of the drill rod has an octagonal section which engages in the chuck of the drill motor. The centre of the drill rod is hollow allowing water to flow through the centre for lubricating the cutting tip and removing the fines produced by the drilling of the hole. With the drill motor in the correct position, the drill rod is inserted into the chuck and thrust applied until the cutting tip reaches the strata. Once the cutting tip is at the face of the strata, water is injected into the drill rod and thrust applied sufficient to drill the hole while preventing the drill rod from bending or undergoing plastic deformation. When the hole has reached the required depth, water is left running through the drill rod for a sufficient time to flush the fines from the hole. The drill motor is then retracted to its initial starting position and the drill rod removed from the chuck.

[0004] A driving socket or rock bolting “dolly” (according to the prior art as shown in figure 1) is now fitted to the drill motor chuck 201 of a rock bolt drilling machine as shown in figure 2A. The rock bolting dolly has a recessed, typically octagonal socket at its outer end for engagement with the nut of a rock bolt. The dolly has a long hollow section below the octagonal socket to enable the drill motor 202 to push a rock bolt through the bolting rig head plate (see figure 2) allowing the threaded section of the rock bolt to extend through the centre of the dolly when tensioning the rock bolt. The drill motor 202 extends to head plate and provides rotation to drill rod.

[0005] A rock bolt (see figure 3), in this example, a chemical anchor rock bolt, is now inserted into the drilled hole and the drill motor and dolly extended to engage with the nut of the bolt. The drill motor is now activated to rotate the bolt and thrust applied to drive the bolt fully into the hole. This action causes the chemical resin anchor to be mixed around the annulus around the rock bolt. The resin of the chemical anchor has a predefined spin time to allow the resin catalyst to mix and form a chemical bond. The nut at the end of the rock bolt and which is seated in the socket of the dolly, has a shear pin preventing its rotation along the threaded section of the bolt until the bond is sufficiently formed between the rock bolt, the chemical anchor and the strata. Until the resin has cured according to a pre-determined set time, rotation of the bolt will not break through its shear pin. When the bond is completed, rotation of the bolt will shear the pin and the nut tensioned to the strata, completing the installation. The drill motor and dolly are then retracted from the bolt and returned to the starting position for a next installation. As illustrated in figure 3, when rock bolt nut prior to tensioning 203 - the nut is secured via a split pin and does not break until the resin capsule is set. See the minimal thread protruding through the bolt; when rock bolt nut post tensioning 204 - the resin has secured the bolt to the strata and the nut breaks and tensions (note the thread is extended). The thread travels through the centre of the dolly.

[0006] In the above process, the need to install a dolly of the prior art into the drill motor chuck after every hole drilling operation adds time to the process. Moreover, when a dolly under the current procedure is removed from the drill chuck in readiness for a following drilling operation, it is easily mislaid in the typically dark environment of a mine, leading to inefficiency and even loss of equipment.

[0007] It is an object of the present invention to address or at least ameliorate some of the above disadvantages.

Notes

[0008] The term “comprising” (and grammatical variations thereof) is used in this specification in the inclusive sense of “having” or “including”, and not in the exclusive sense of “consisting only of’.

[0009] The above discussion of the prior art in the Background of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled in the art in any country. SUMMARY OF INVENTION

[00010] According to one broad form of the invention, there is provided a drilling and bolting dolly driving a drill rod in a first phase of a rock bolting operation and driving a nut of a rock bolt in a second phase of the rock bolting operation.

[00011] Preferably, the dolly is adapted for engagement with a chuck of a rock bolt drilling machine.

[00012] Preferably, the dolly comprises a chuck of a rock bolt drilling machine.

[00013] Preferably, a portion of the length of the dolly is provided proximate a lower end with an integral nut for engagement with the chuck of the rock bolt drilling machine.

[00014] Preferably, a portion of the length of the dolly is provided at an upper end with a socket for engagement with either a drive portion of a drill rod or with a nut of a rock bolt. [00015] Preferably, a passage extends from below the socket; the passage accommodating a tail of a drill rod or a threaded section of a rock bolt extending from below the nut of the rock bolt.

[00016] Preferably, a cylindrical chamber is located within the dolly below the passage; the cylindrical chamber further providing for any further length of threaded section of the rock bolt.

[00017] Preferably, a water passage extends from a lower end of the dolly to the cylindrical chamber.

[00018] Preferably, the cylindrical chamber is provided with a spring-loaded water flow control element; the control element comprising a stem depending from a disc; a water passage extending through the stem communicating with an opening in the disc; the spring acting between a lower surface of the cylindrical chamber and an underside of the disc.

[00019] Preferably, a lower end of the tail of a drill rod is seated against an upper surface of the disc when a drill rod is inserted into the dolly; the water passage extending from the lower end of the dolly, the water passage through the stem of the water flow control element and a water passage of the drill rod then forming a continuous water passage of substantially equal diameter.

[00020] Preferably, the spring of the spring-loaded water flow control element allows the disc to be depressed downwardly in the cylindrical chamber by the threaded end of a rock bolt according to any further length of treaded section of the rock bolt intruding into the dolly. [00021] According to another broad form of the invention there is provided a method of installing a rock bolt with a dolly adapted for engagement with a drill rod and with a rock bolt in successive operations of a rock bolt installation; the method including the steps of: providing a dolly with an internal water passage, aligning a rock bolt drilling machine with a selected location for the rock bolt with the drilling machine in a retracted position, fitting a drilling rod to an upper end of the dolly, bringing a tip of the drilling rod to strata to be drilled, initiating water flow through the drilling machine, the dolly and the drilling rod, applying thrust and rotation to the drill rod and drilling a hole in the strata until reaching required depth of the hole.

[00022] Preferably, the installation includes the further steps of; stopping rotation of the drilling machine and shutting off the water flow, returning the drilling machine to the retracted position and removing the drill rod from the dolly, fitting a rock bolt to the end of the dolly, a nut of the rock bolt seating in a socket of the dolly, driving the dolly to insert the rock bolt into the drilled hole, rotating the dolly and the rock bolt to activate an anchor of the rock bolt, continuing rotation of the nut of the rock bolt after the anchor has formed a bond with the strata to tension the rock bolt in the strata.

[00023] Preferably, the dolly is adapted for engagement with a chuck of a rock bolt drilling machine.

[00024] Preferably, the dolly comprises a chuck of a rock bolt drilling machine.

[00025] Preferably, the dolly is provided with a spring-loaded water flow control element; a water passage through the spring-loaded water flow control element being of a diameter substantially equal to both a water passage in a lower portion of the dolly and a water passage through the drill rod; the spring loaded water flow control element preventing delay in water delivery to a drilling tip of the drill rod.

[00026] Preferably, in a drilling phase of the rock bolt installation, a spring of the spring- loaded water flow control element urges the control element into contact with a lower end of the drill rod.

[00027] Preferably, the spring of the spring-loaded water flow control element provides for the control element to be depressed to a lower level within the dolly by intrusion of a threaded end of a rock bolt.

[00028] According to another broad form of the invention, there is provided a drilling and bolting dolly providing engagement between a chuck of a rock bolt drilling machine and a drill rod in a first phase of a rock bolting operation and between the chuck and a rock bolt in a second phase of the rock bolting operation; the dolly including a socket at an upper end of the dolly sized to receive either an integral nut of a drill rod or a nut of a rock bolt.

[00029] Preferably, the dolly includes a passage depending from below the socket; the passage sized to accept either the tail of a drill rod or a length of threaded end of a rock bolt extending from the nut.

[00030] Preferably, a lubricating fluid passage extends from a lower end of the dolly to communicated with the passage below the socket; the lubricating fluid passage passing lubricating fluid to a lubricating fluid passage of a drill rod when the tail of the drill rod is located in the passage below the socket.

[00031] Preferably, the dolly further includes an integral nut proximate the lower end of the dolly for engagement with the chuck of the drilling machine.

[00032] According to another broad form of the invention there is provided a dolly for driving a drill rod in a first phase of a rock bolting operation and a nut of a rock bolt in a second phase of a drilling operation; the dolly forming a chuck of a rock bolt drilling machine. [00033] Preferably, a portion of the length of the dolly is provided at an upper end with a socket for engagement with either a drive portion of a drill rod or with a nut of a rock bolt. [00034] Preferably, a passage extends from below the socket; the passage accommodating a tail of a drill rod or a threaded section of a rock bolt extending from below the nut of the rock bolt.

[00035] Preferably, a cylindrical chamber is located within the dolly below the passage; the cylindrical chamber further providing for any further length of threaded section of the rock bolt.

[00036] Preferably, a water passage extends from a lower end of the dolly to the cylindrical chamber.

[00037] According to another broad form of the invention, there is provided a drilling and bolting dolly providing engagement between a chuck of a rock bolt drilling machine and a drill rod in a first phase of a rock bolting operation and between the chuck and a rock bolt in a second phase of the rock bolting operation.

[00038] Preferably, a portion of the length of the dolly is provided proximate a lower end with an integral nut for engagement with the chuck of the rock bolt drilling machine.

[00039] Preferably, a portion of the length of the dolly is provided at an upper end with a socket for engagement with either a drive portion of a drill rod or with a nut of a rock bolt. [00040] Preferably, a passage extends from below the socket; the passage accommodating a tail of a drill rod or a threaded section of a rock bolt extending from below the nut of the rock bolt.

[00041] Preferably, a cylindrical chamber is located within the dolly below the hollow section; the cylindrical chamber further providing for any further threaded section of the rock bolt.

[00042] Preferably, a water passage extends from a lower end of the dolly to the cylindrical chamber.

[00043] Preferably, the cylindrical chamber is provided with a spring-loaded water flow control element; the control element comprising a stem depending from a disc; a water passage extending through the stem communicating with an opening in the disc; the spring acting between a lower surface of the cylindrical chamber and an underside of the disc. [00044] Preferably, a lower end of the tail of a drill rod is seated against an upper surface of the disc when a drill rod is inserted into the dolly; the water passage extending from the lower end of the dolly, the water passage through the stem of the water flow control element and a water passage of the drill rod then forming a continuous water passage of substantially equal diameter.

[00045] Preferably, the spring of the spring-loaded water flow control element allows the disc to be depressed downwardly in the cylindrical chamber by the threaded end of a rock bolt according to any further treaded section of the rock bolt intruding into the dolly.

[00046] According to another broad form of the invention, there is provided a method of installing a rock bolt with a dolly adapted for engagement with a drill rod and with a rock bolt in successive operations of a rock bolt installation; the method including the steps of: providing a dolly with an internal water passage, in a first phase of the operation fitting a lower end of the dolly to a chuck of a rock bolt drilling machine with the chuck in a retracted position, aligning the rock bolt drilling machine with a selected location for the rock bolt, fitting a drilling rod to an upper end of the dolly, bringing a tip of the drilling rod to strata to be drilled, initiating water flow through the chuck, the dolly and the drilling rod, applying thrust and rotation to the chuck and drilling a hole in the strata until reaching required depth of the hole.

[00047] Preferably, the installation includes the further steps of; stopping rotation of the chuck and shutting off the water flow, returning the chuck and dolly to the retracted position and removing the drill rod from the dolly, fitting a rock bolt to the end of the dolly, a nut of the rock bolt seating in a socket of the dolly, driving the chuck and dolly to insert the rock bolt into the drilled hole, rotating the chuck and dolly to rotated the rock bolt to activate an anchor of the rock bolt, continue rotation of the nut of the rock bolt after the anchor has formed a bond with the strata to tension the rock bolt in the strata.

[00048] Preferably, the dolly is provided with a spring-loaded water flow control element; a water passage through the spring-loaded water flow control element being of a diameter substantially equal to both a water passage in a lower portion of the dolly and a water passage through the drill rod; the spring loaded water flow control element preventing delay in water delivery to a drilling tip of the drill rod.

[00049] Preferably, in a drilling phase of the rock bolt installation, a spring of the spring- loaded water flow control element urges the control element into contact with a lower end of the drill rod.

[00050] Preferably, the spring of the spring-loaded water flow control element provides for the control element to be depressed to a lower level within the dolly by intrusion of a threaded end of a rock bolt.

[00051] According to another broad form of the invention, there is provided a drilling and bolting dolly providing engagement between a chuck of a rock bolt drilling machine and a drill rod in a first phase of a rock bolting operation and between the chuck and a rock bolt in a second phase of the rock bolting operation; the dolly including an integral nut proximate a lower end of the dolly for engagement with the chuck of the drilling machine and a socket for engagement with a drill rod or a nut of a rock bolt at an upper end; the dolly further including a fluid conducting passage extending from the lower end of the dolly to communicate with a chamber below the socket.

BRIEF DESCRIPTION OF DRAWINGS

[00052] Embodiments of the present invention will now be described with reference to the accompanying drawings wherein:

[00053] Figure 1 is a driving element or dolly for the installation of a rock bolt into strata according to prior art; [00054] Figure 2A is a representation of a rock bolt drilling machine, motor and chuck for installing rock bolts for use with some preferred embodiments of the invention;

[00055] Figure 2B is a representation of a rock bolt drilling machine in which the chuck is replaced with an embodiment of the dolly according to the invention;

[00056] Figure 3 shows rock bolts prior to installation and after tensioning against strata;

[00057] Figure 4 is a cross section of a dolly according to a preferred embodiment of the invention,

[00058] Figure 4A is an end view of the dolly of figure 4 showing cross sections of the dolly,

[00059] Figure 4B is an end section of a drilling rod for drilling a rock bolt hole,

[00060] Figure 5 is a cross section of the dolly of figure 4 when in use for drilling into strata,

[00061] Figure 6 is a cross section of the dolly of figure 4 at the completion of tensioning a rock bolt against strata,

[00062] Figure 7 is a cross section of a dolly according to a second preferred embodiment of the invention.

DESCRIPTION OF EMBODIMENTS First Preferred Embodiment

[00063] The dolly of the present invention eliminates the step of removing a dolly according to the prior art each time a rock bolt has been installed to allow the fitting of a drill rod into the drilling machine chuck for the next installation.

[00064] With reference to figures 4, 4A and 4B, a drilling and bolting dolly 10 conforms in its external diameters to the prior art dolly of figure 1. Similar to that dolly, the lower end 12 of the dolly 10 is provided with an integral nut 14 for engagement with a socket of the chuck of a rock bolt drilling machine such as the one shown in figure 2. Again, similar to a dolly of the prior art, the upper end of the dolly 10 is provided with a socket 16 for engagement with an integral nut 18 formed at a lower end 20 of a drill rod 22 shown in figure 4B. Also, in common with dollys of the prior art, a passage 24 extends downwardly from the socket 16 to accommodate the tail 26 of the drill rod 22 as shown in figure 5.

[00065] In the dolly 10 of the present invention, it will be noted however, that the overall length of the dolly 10 is considerably shorter than dollys of the prior art. Since the dolly 10 is intended to remain in the chuck of the rock bolt drilling machine throughout a rock bolt installation process, drill rods for use with the dolly 10 are shorter than those which currently fit directly into a drilling machine chuck.

[00066] The dolly 10 is further provided with a cylindrical chamber 28 located below the passage 24. One function of this chamber 28, as shown in figure 6, is to provide for a section of the threaded end 30 of a rock bolt 32 as it extends from below the rock bolt nut 34 during tensioning of the bolt as will be described below. The other function of the chamber 28 is to house a spring-loaded water flow control element 36. Control element 36 comprises a stem 38 depending from a disc 40. The disc 40 operates as a close sliding fit within the chamber 28, while the lower end of the stem 38 extends as a sliding fit into a water passage 42 which extends from the lower end 12 of the dolly to the chamber 28. The spring 43 of the spring- loaded water flow control element 36 acts between the underside of the disc 40 and the bottom of the chamber 28. A water or lubricating liquid passage 44 extends through the stem 38 and communicates with an opening 44 in the disc 40 at its upper end and with the water passage 44 at its lower end.

[00067] During a drilling operation, as shown in figure 5, the disc 40 of the control element 36 is urged by the spring 43 to the top of chamber 28 and into contact with the end of the tail 26 of the drill rod 22. The diameters of the water passages 42 and 44 are substantially equal to the water passage 46 which extends the length of the drill rod 22, forming a continuous water passage from the lower end of the dolly to the drilling tip of the drill rod.

By this means, any delay in delivery of water to the drilling tip of the drill rod is prevented by water flow control element 36 eliminating the volume of space otherwise obtaining in chamber 28.

[00068] During a rock bolt tensioning operation, rotation of the nut 34 relative the rock bolt will cause a section of the threaded end 30 of the rock bolt 32 to increasingly extend from below the nut 34 as shown in figure 6, and, if that extension exceeds the length of the passage 24, the end of the bolt can depress the disc 40 downwardly against the spring 43 to accommodate that excess length.

Second Preferred Embodiment

[00069] In this second preferred embodiment of a dolly 100 for use in both the drilling of a rock bolt hole and the rock bolt installation, the dolly of this embodiment as shown in figure 7, is externally configured in the manner of the dolly of the first embodiment above and shown in figure 4. As for that first embodiment also, the dolly 100 is provided with a socket 116 for engagement with either the end of a drilling rod or the nut of a rock bolt. Again, as for the first embodiment, the dolly 100 is provided with a lubricating fluid passage 142 extending from the lower end of the dolly and communicating with a chamber 124 below the socket 116.

[00070] In this second embodiment however, the relatively narrow water passage 142 extends all the way to the chamber 124 and is devoid of the valve arrangement of the first embodiment. In this instance the chamber 124 is of the same diameter adapted to accept either the tail of a drill rod or the threaded end of a rock bolt, and is of sufficient depth to accommodate any length of thread projecting from the nut of a rock bolt at the completion of the rock bolt tensioning.

Third Preferred Embodiment

[00071] In this further embodiment, the dolly as described above forms a component of a drilling machine as shown in figure 2B. That is instead of a chuck into which a dolly of the first two embodiments above, may be inserted, the dolly replaces the chuck and the machine directly drives the dolly. In this instance the device of the invention comprises a dolly/chuck of a rock bolt drilling machine.

In Use - Drilling the Rock Bolt Hole

[00072] The method of use of the dolly 10 (or 100) of the invention for the drilling of a rock bolt hole is as follows for the first two preferred embodiments above. With the chuck of the drilling machine in its retracted starting position, the lower end 12 of the dolly 10 is fitted to the chuck and the end 20 of a drill rod 22 fitted into the socket 16 and passage 24 at the upper end of the dolly. The drilling machine is aligned with the intended position for the rock bolt and the tip of the drill rod brought to the strata. Flow of water or lubricating fluid is then initiated trough the chuck, and the passage 42 through the lower end of the dolly, the lubricating fluid flow control element 36 (in the case of the first preferred embodiment) and through the drill rod 22 and thrust and rotation applied to the chuck to drill the hole into the strata to the required depth.

[00073] Rotation of the chuck is stopped and the flow of water shut off. The dolly 10 and the drill rod 22 are then retracted with the chuck back to the chuck starting position and the drill rod removed from the dolly. The dolly remains in the chuck of the drilling machine. [00074] For the Third Preferred Embodiment, the procedure is similar but, in this instance, a drill rod is directly placed in the dolly/chuck of the drilling machine. In Use - Installing the Rock Bolt

[00075] A rock bolt 32 is now fitted to the end of the dolly 10 with the nut 34 of the rock bolt seated in the socket 16 of the dolly, and any length of thread 30 extending from the nut accommodated in the passage 24. The drilling machine chuck and dolly are then advanced to insert the rock bolt into the drilled hole. The chuck is rotated to rotate the dolly and thus the nut and the rock bolt together to activate the anchor of the rock bolt. During this predetermined period of rotation, in the case of a chemical anchor, the ribs around the bolt mix the chemicals which harden to bond the bolt to the surrounding strata. Up to this point a shear pin has prevented the nut rotating on the rock bolt thread but with the bond established the pin shears and continued rotation of the chuck and dolly advances the nut on the thread of the bolt to tension the bolt against the strata. The chuck and dolly 10 are retracted with the dolly 10 remaining in the chuck ready for the next hole drilling operation.

[00076] For the Third Preferred Embodiment, the process is similar in all respects except that in this instance it is the nut of the rock bolt which is fitted to the dolly/chuck of the drilling machine.




 
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