WO2014089638A1

WO2014089638A1 - Adapter for a cable bolt tensioner

Info

Publication number: WO2014089638A1
Application number: PCT/AU2013/001468
Authority: WO
Inventors: Peter Mastalir
Original assignee: Rambor Logistics & Asset Management Pty Ltd
Priority date: 2012-12-14
Filing date: 2013-12-13
Publication date: 2014-06-19
Also published as: AU2013359961A1

Abstract

The present invention relates to an adaptor (1) for connecting a cable bolt tensioner device (11) to a drilling rig (12). The adaptor (1) includes a mount (2) adapted to be connected to the cable bolt tensioner device (11), a base (3) adapted to be connected to the drilling rig (12) and a support section (4) connected between the mount (2) and the base (3). The support section (4) supports the mount (2) in a spaced apart position from the base (3) and includes at least one resiliently deformable member (7) to allow the mount (2) to be displaced relative to the base (3).

Description

ADAPTER FOR A CABLE BOLT TENSIONER TECHNICAL FIELD

The present invention relates to the field of mining equipment and in particular, apparatus to support a cable bolt tensioner during the installation of cable bolts in strata .

BACKGROUND TO THE INVENTION

Cable bolts are a commonly used type of roof support installed during mining or civil engineering projects to provide structural integrity to the roof of a tunnel. Also known as rock bolts, they are formed from a length of flexible, multi-core cable and are secured within loose rock surrounding a tunnel, known as strata, to compress the strata and transfer loads from an unstable surface of the tunnel to a stable, compact interior of rock mass.

To ensure the structure of a tunnel is stable, cable bolts are nearly always installed in an array within the roof or walls of the tunnel at regular intervals along its length . Each bolt is installed by inserting the bolt into a bore hole drilled through the strata and securing an end of the bolt at the base of the hole using a chemical or mechanical anchor.

Once a cable bolt has been anchored, a cable bolt tensioner is used to 'pretension' a cable, i.e. increase the tensile force in the cable and compress the strata further together, prior to grout being injected into the bore hole to fill the cracks that remain between the strata and set the rock firmly in place. Tension may be applied linearly, i.e. by stretching the cable taught and applying a collar to prevent the cable retracting within the hole, or rotationally, where tension is created by winding a threaded component that connected to the cable into a collar fixed to the strata.

A cable bolt tensioner is typically configured as a hand-held device having a cylindrical recess adapted to receive an end of a cable bolt and a mechanism to apply tension to the cable bolt. In use, a tensioner is often manually attached to an end of a cable bolt protruding from a bore hole in the roof of a tunnel, sometimes over 3 metres high . This usually involves a worker climbing a ladder and lifting the tensioner, which weighs approximately 17-25 kg, above head height to connect the tensioner to the bolt. In some instances, this process may also require the worker to continue to hold the unit in place whilst tension is applied to the cable. This activity, often performed many times during a working day, presents a significant risk to the safety of the worker as not only does it require the worker to lift a heavy item into an awkward position whilst being precariously balanced on a ladder but also, due to the high forces involved in tensioning cable bolts, can result in the tensioner jerking uncontrollably when locked onto the cable bolt, potentially causing the worker to fall from a ladder. Furthermore, hydraulic tensioners are known to occasionally leak high pressure hydraulic fluid in close proximity to the worker, potentially harming the worker and also causing a fall from the ladder.

One attempt to overcome the health risks associated with manual attachment of cable bolt tensioners has been the use of machines, commonly being different sorts of drilling rigs, such as 'mobile bolters' or 'mobile drilling rigs', to automate the engagement of the tensioner with the cable bolt. When tensioners are used in this manner, it is common for the tensioner to be fixed to or have a shaft which is secured within a port, such as a chuck, in the drilling rig and the tensioner raised or lowered by an automated boom, in order to lift the tensioner and engage an end of the cable bolt. The tensioner is then operated remotely to apply tension to the bolt.

A major drawback with this arrangement is that the roofs of underground environments in which cable bolts are tensioned often arranged at an angle from horizontal, resulting in cable bolts protruding from the roof arranged at an angle to the cable bolt receiving recess within the cable bolt tensioner connected to the drilling rig . When the tensioner is engaged with the cable bolt in this scenario, there is often a misalignment between the cable bolt and the receiving recess which, during the engagement and tensioning process, can exert non-axial forces from the tensioner, through the connecting shaft, to the port in the drilling rig the tensioner is connected to. This can involve significant non-axial forces being transferred to the port which, particularly where the port is a chuck and is not specified to withstand such forces, can damage the drilling rig, causing machine downtime and increasing maintenance costs. Furthermore, many drilling rig manufacturers disclaim damage caused to chucks by non-axial loading from machine warranties, which can dramatically increase the cost of maintenance to an underground construction company.

Accordingly, it would be useful to provide an apparatus to assist using a cable bolt tensioner, in conjunction with a drilling rig, to engage and apply tension to cable bolts protruding from surfaces arranged at an angle to the tensioner that reduces or mitigates damage to the drilling rig. Furthermore, it would be advantageous to provide an apparatus that avoids or alleviates any of the disadvantages present in the prior art, or which at least provides a useful alternative to the prior art approaches.

SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided an adaptor for connecting a cable bolt tensioner device to a drilling rig, the adaptor comprising a mount adapted to removably connect to the cable bolt tensioner device, a base adapted to removably connect to the drilling rig and a support section connected between the mount and the base defining a longitudinal axis, wherein the support section supports the mount in a spaced apart position relative to the base and includes at least one resiliently deformable member, thereby allowing the mount to be displaced relative to the base.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which : Figure 1 is a perspective view of a cable bolt tensioner adaptor;

Figure 2 is a perspective view of the adaptor shown in Figure 1 connected to a mobile drilling rig and a hydraulic cable bolt tensioner;

Figure 3 is a perspective view of an alternative cable bolt tensioner adaptor attached to the mobile drilling rig and hydraulic cable bolt tensioner;

Figure 4 is an exploded view of cable bolt hardware components shown above the assembly shown in Figure 2;

Figure 5 is a perspective view of the assembly shown Figure 4 below a cable bolt;

Figure 6 is a perspective view of the assembly shown in Figure 5 engaged with the cable bolt;

Figure 7 is a cross-section view of the assembly shown in Figure 6;

Figure 8 is perspective view of the assembly shown in Figure 7 where the cable bolt tensioner is extended to tension the cable bolt;

Figure 9 is side view of the shown in Figure 8, positioned under an angled roof surface;

Figure 10 is a cross-section view of the assembly shown in Figure 9; and

Figure 11 is a side view diagram of yet another alternative cable bolt tensioner adaptor, configured to attach a torque multiplier tensioner to the mobile drilling rig .

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention relates to an adaptor to connect a cable bolt tensioner to apparatus for positioning the tensioner in relation to a cable bolt protruding from a bore hole. In particular, the invention relates to a deformable adaptor for connecting a hydraulic, mechanical or pneumatic cable bolt tensioner to a drilling rig chuck, the adaptor having one or more resiliently deformable portions to allow the cable bolt tensioner to be displaced with respect to the chuck. The adaptor may also reduce non-axial forces exerted on the chuck by the tensioner during use. The adaptor is configurable to support different cable bolt tensioner devices above a drilling rig, including a linear tensioner which increases tension in the cable bolt by applying linear force, or a torque multiplier tensioner which increases tension in the cable bolt by rotating a threaded collar connected to the cable bolt.

The adaptor comprises a support section that is resiliently deformable and connects a cable bolt tensioner dock, adapted to connect to a cable bolt tensioner, to a seating flange assembly, adapted to connect to a chuck in a drilling rig, such that the dock is supported in a spaced apart position from the seating flange assembly and may be displaced in relation to the seating flange assembly. The support section is biased to support and maintain the position of the dock and an attached cable bolt tensioner substantially above the seating flange assembly when the flange is connected to a chuck. The support section defines a longitudinal axis between the flange and dock and is adapted to be more resistant to a compressive force exerted on the section, substantially parallel to the longitudinal axis, than a bending or shear force exerted transverse to the longitudinal axis. The seating flange assembly includes a shaft, adapted to be gripped by a chuck or similar clamp and a base, arranged radial to the shaft and connected to the support section . When the adaptor is connected to a drilling rig, the base is placed in contact with the body of the drilling rig and at least partially transfers non-axial forces exerted on the support section to the body of the drilling rig.

The adaptor may also comprise one or more components to limit the movement of the dock in relation to the seating flange assembly. Each component is preferably flexible and fixed in length, thereby allowing the dock to be displaced relating to the flange within a limited range. Alternatively, one or more resiliently deformable components may at least partially surround the support section to restrict the movement of the dock relative to the flange.

In Figure 1, a deformable adaptor 1 for connecting a cable bolt tensioner to an item of mining or construction apparatus is shown, the adaptor 1 having a cable bolt tensioner dock 2 or mount arranged at a first end, a seating flange assembly 3 for connection to the construction apparatus arranged at a second end and a support section 4 connecting in between . The dock 2 includes a shaft 5 adapted to fit within a cable bolt tensioner, and a fixing plate 6 adapted to connect to a surface of the tensioner, the fixing plate 6 having an array of apertures through which fasteners are securable to connect the tensioner to the dock 2. Whilst a particular dock 2 embodiment is shown in Figure 1, it will be appreciated that the arrangement of the shaft 5 and fixing plate 6 is optimised for a particular cable bolt tensioner and that other configurations of dock 2 features may be provided according to the requirements of alternative tensioners.

Figure 2 shows the adaptor 1 connected between a linear cable bolt tensioner 11 and a mobile drilling rig 12. The tensioner 11 has two hydraulic hoses 13 secured at one side which provide a driving fluid to the tensioner 11 to operate the tensioner 11. Whilst a linear, hydraulic cable bolt tensioner 11 is shown, the adaptor 1 may also be configured to connect other tensioners, such as a torque multiplier type tensioner, to a mobile drilling rig 12. The resiliently deformable element 7 is specified to be sufficiently rigid to support the tensioner 11 and dock 2 above the seating flange assembly 3 and prevent the tensioner 11 toppling during transit of the mobile bolter 12.

The support section 4 is fixed to the fixing plate 6 and includes at least one resiliently deformable element 7, which connects between the dock 2 and the seating flange assembly 3. The resiliently deformable element 7 is deformable, allowing displacement of the dock 2 relative to the seating flange assembly 3 to allow the tensioner 11 to be reorientated to engage with the cable bolt. As the element 7 is resilient, it returns to a default position after each displacement to position the dock 2 substantially above the flange assembly 3. In the example shown, the resiliently deformable element 7 is a coil spring however other elements, such as an elastomer rod, may also be appropriate. The seating flange assembly 3 has a base 8 to which the resiliently deformable element 7 is fixed and a shaft 9, extending perpendicular to the base 8, the shaft 9 adapted to be secured within a chuck or port in the mobile drilling rig 12. The support section 4 defines a longitudinal axis and the shaft 9 also has an axis arranged collinear with the longitudinal axis of the support section 4. The base 8 has at least one surface extending radially to the shaft 9 providing a flange, which can be placed against a complimentary surface of the drilling rig 12 when the adaptor is connected to the drilling rig 12, thereby allowing forces exerted by the resiliently deformable element 7 against the base 8 to be transferred to the surface of the drilling rig 12, potentially reducing forces transferred to the shaft 9 and the chuck or clamp of the drilling rig 12 gripping the shaft 9. The flange surface is typically configured as a planar surface, due to the planar surfaces present on drilling rigs which the flange surface may be placed in contact with .

The support section 4 of the adaptor 1 also includes a plurality of motion limiter components 10 to restrict the movement of the dock 2 with respect to the seating flange assembly 3. Each motion limiter component 10 is arranged at regular intervals concentric to the support section 4 and connected to the base 8 and fixing plate 6. Each component 10 is substantially flexible and fixed in length . This ensures that the tensioner 11 and dock 2 can be displaced relative to the seating flange assembly 3 during use within a defined limit and that further displacement would be prevented by one or more of the motion limiter components 10 being pulled taught. The limitation of the displacement of the tensioner and dock 2 potentially reduces damage to the one or more resiliently deformable elements 7, by preventing plastic deformation due to excessive bending . Whilst the motion limiter components 10 are configured as chains in Figure 1, other equivalent components, such as cables, ropes and the like may be used to provide a similar function . Each motion limiter component 10 may also be surrounded by a flexible, protective material (not shown), such as "mine sleeve", to prevent each component 10 from being damaged due to abrasion, heat, humidity and the like.

In an alternative adaptor embodiment (not shown) each motion limiter component is a hydraulic piston or ram rotatably connected to the base 8 and fixing plate 6 and configured to dampen a compressive and/or tensile force exerted along the length of the ram. The connection between each ram and the base 8 and fixing plate 6 is preferably rotatable around more than one axis, thereby allowing greater flexibility of movement of the dock 2 relative to the seating flange assembly 3. The dampening provided by each ram may be adjustable according to the requirements of the adaptor or may vary dependent on the extension of each ram.

In Figure 3 an alternative deformable adaptor 20 is shown connected between the cable bolt tensioner 11 and the mobile bolter device 12. The adaptor 20 includes a first resiliently deformable element 21 positioned within a second resiliently deformable element 22, the second element 22 specified to be more flexible than the first element 21. This may provide a more rigid connection between the tensioner 11 and mobile drilling rig 12 than the adaptor 1 shown in Figures 1-2 due to the dual resiliently deformable element arrangement, which may be appropriate for heavier tensioner devices.

Figure 4 shows the assembly illustrated in Figure 2 with conventional cable bolt fixing hardware 31-33 components positioned above the tensioner 11. The fixing hardware 31-33 includes a washer plate 31, barrel 32 and wedge 33 which are attached to the cable bolt by the tensioner 11 once the bolt has been tensioned, to prevent the bolt from retracting within a bore hole and decreasing compressive force applied to surrounding strata.

Figure 5 shows the assembly shown in Figure 4 during a first stage of operation of the tensioner 11 to tension the cable bolt 34. The tensioner 11 is shown engaged with the fixing hardware components 31-33 and positioned by the mobile drilling rig 12 below the cable bolt 34 suspended from a bore hole in the roof 35 of a tunnel. The shaft 9 of the seating flange assembly 3 is shown gripped within a chuck 36 the mobile drilling rig 12 and the base 8 is positioned against a surface of the body 37 of the drilling rig 12.

Figure 6 shows the assembly shown in Figure 5 where the tensioner 11 and associated fixing hardware components 31-33 have been lifted by the mobile drilling rig 12 and engaged with the cable bolt 34, pressing the tensioner 11 and hardware components 31-33 against the roof surface 35. The resiliently deformable element 7 is shown compressed and the motion limiter components 10 slack due to the drilling rig 12 urging the tensioner 11 against the roof surface 35, causing the resiliently deformable element 7 to transfer an equal and opposite force to the base 8 and body 37 of the drilling rig 12.

Figure 7 is a cross-section view of the assembly shown in Figures 5 and 6, showing an internal sleeve 38 of the tensioner 11 engaged with the end of the cable bolt 34 during its first stroke of operation, pushing against the fixing components 31-33 and roof 35 and retracting the cable bolt 34 within the tensioner 11. Due to the force exerted against the surface of the roof 35 by the sleeve 38, the resiliently deformable element 7 is compressed and, in some instances, may also bend to accommodate any axial misalignment between the tensioner 11 and the shaft 9 gripped by the chuck 36 of the mobile drilling rig 12. Forces generate by the compression and possible bending of the resiliently deformable element 7 are transferred to the base 8, which the resiliently deformable element 7 is fixed to, and to the body 37 of the mobile drilling rig 12.

Following this action (not shown), the sleeve 38 of the tensioner 11 is retracted within the tensioner 11, relieving the force against the roof surface 35 and allowing the resiliently deformable element 7 to return to its default position, thereby urging the tensioner 11 upwards towards the washer plate 31 and roof 35 before the second stroke of operation of the tensioner 11.

Figure 8 shows the assembly shown in Figures 5-7 during the second stroke of operation of the tensioner 11, in which the internal sleeve 38 is again urged towards the roof surface 35, applying tension to the cable bolt 34 and compressing the resiliently deformable element 7.

Figures 9 and 10 show the assembly shown in Figures 5-8 positioned underneath an angled, non-horizontal roof surface 39. The internal sleeve 38 of the tensioner 11 is shown extended towards the roof surface 39 urging the washer plate 31, barrel 32 and wedge 33 against the roof 39 and retracting the cable bolt 34 within the tensioner 11, increasing tension in the bolt 34. As the tension is increased in the cable bolt 34, the washer plate 31 is forced against the roof surface 39 adjacent to the cable bolt 34, causing the longitudinal axis of the tensioner 11 to be reorientated substantially perpendicular to the washer plate 31 and collinear with the axis of the tensioned cable bolt 34. The reorientation of the tensioner 11 consequently displaces the dock 2 relative to the seating flange assembly 3 and bends the resiliently deformable element 7. The misalignment between the dock 2 and flange assembly 3 generates non-axial forces which are at least partially transferred from the resiliently deformable element 7 to the base 8 and to the body 37 of the mobile drilling rig 12, thereby reducing non-axial force transferred from the shaft 9 to the chuck 36.

In Figures 9 and 10, the motion limiter components 10 are shown reacting to the motion of the tensioner 11 and adaptor 1, whereby the component 10 on the outside of the bend of the resiliently deformable element 7 has been drawn taught. Should the bend of the resiliently deformable element 7 progress much further, the component 10 would be unable to extend in length and would restrain the tensioner 11 and associated dock 2 from moving further out of alignment with the seating flange assembly 3, thereby reducing or preventing permanent damage to the resiliently deformable element 7.

Figure 11 illustrates an alternative deformable adaptor 40 configured to connect a torque multiplier 41 to the mobile drilling rig (not shown). The adaptor 40 has an alternative cable bolt tensioner fixing plate 42 having an aperture to allow a flexible drive 43, connected to the mobile drilling rig, to be passed through and connect to the torque multiplier 41 to provide rotational drive necessary to increase tension in a cable bolt 44 engaged by the torque multiplier. The adaptor 40 operates substantially identically to the previously described adaptor 1, having at least one resiliently deformable element 45 connecting the fixing plate 42 to a seating flange assembly 46 thereby allowing displacement of the fixing plate 42 relative to the seating flange assembly 46. In instances where the resiliently deformable element 45 becomes bent during use of the torque multiplier 41 to tension the cable bolt 44, the flexible drive 43 connected between the mobile drilling rig and the torque multiplier 41 is also bends and deforms, to maintain drive being communicated from the drilling rig to the torque multiplier 41.

It will be apparent that obvious variations or modifications may be made which are in accordance with the spirit of the invention and which are intended to be part of the invention . Although the invention is described above with reference to specific embodiments, it will be appreciated that it is not limited to those embodiments and may be embodied in other forms.

INDUSTRIAL APPLICABILITY

The invention can be utilised in construction, mining or any other industry in which it is necessary to use a cable bolt tensioner in conjunction with a mobile bolter or similar apparatus.

Claims

An adaptor for connecting a cable bolt tensioner device to a drilling rig, the adaptor comprising : a mount adapted to removably connect to the cable bolt tensioner device; a base adapted to removably connect to the drilling rig; and a support section connected between the mount and the base defining a longitudinal axis; wherein the support section supports the mount in a spaced apart position relative to the base and includes at least one resiliently deformable member, thereby allowing the mount to be displaced relative to the base.

An adaptor in accordance with claim 1, wherein the base includes a shaft arranged substantially parallel to the longitudinal axis and a flange having at least one planar surface extending radially from the shaft.

An adaptor in accordance with claim 2, wherein each resiliently deformable member is fixed to the flange.

An adaptor in accordance with claim 2, wherein the shaft is adapted to engage with a chuck.

An adaptor in accordance with claim 1, further comprising a plurality of linking members connected between the base and the mount.

An adaptor in accordance with claim 5, wherein each linking member is flexible and fixed in length .

7. An adaptor in accordance with claim 6, wherein each linking member is a chain .

8. An adaptor in accordance with claim 6, wherein each linking member has a protective sheath at least partially surrounding the linking member.

9. An adaptor in accordance with claim 5, wherein each linking member is a telescopic hydraulic ram adapted to dampen compressive or tensile force exerted on the ram .

10. An adaptor in accordance with claim 9, wherein a first end of each hydraulic ram is rotatably connected to the base around one or more axes, and a second end rotatably connected to the mount around one or more axes.

11. An adaptor in accordance with claim 1, wherein the mount and the base also define a longitudinal axis, and the longitudinal axes of the support section, mount and base are arranged substantially collinear.

12. An adaptor in accordance with claim 1, wherein the at least one

resiliently deformable member is a spring .

13. An adaptor in accordance with claim 1, wherein at least one second resiliently deformable member is arranged concentric to a first resiliently deformable member.

14. An adaptor in accordance with claim 1, wherein a second resiliently deformable member is arranged around a first resiliently deformable member.

15. An adaptor in accordance with claim 13 or 14, wherein each second resiliently deformable member is more flexible than the first resiliently deformable member.

16. An adaptor in accordance with claim 6, wherein the length of each linking member is substantially equal to the length of the at least one resiliently deformable member.

17. An adaptor in accordance with claim 1, wherein the drilling rig is

selected a mobile drilling rig or a mobile bolter.

18. An adaptor in accordance with claim 1, wherein the tensioner device is a hydraulic cable bolt tensioner.

19. An adaptor in accordance with claim 1, wherein the tensioner device is a torque multiplier.