AU2012339057B2

AU2012339057B2 - Rock anchor

Info

Publication number: AU2012339057B2
Application number: AU2012339057A
Authority: AU
Inventors: Wolfgang Ludwig; Andreas Schell
Original assignee: DSI Underground Australia Pty Ltd
Current assignee: DSI Underground Australia Pty Ltd
Priority date: 2011-11-18
Filing date: 2012-10-10
Publication date: 2017-09-14
Anticipated expiration: 2032-10-10
Also published as: DE102011086614A1; AU2012339057A1; WO2013072143A3; WO2013072143A2

Abstract

The invention relates to a rock anchor having an anchor tube (2) and an inner tube (4) disposed inside the anchor tube, an extrudable hardenable mass (7) being disposed inside the inner tube for anchoring the anchor tube (2) in a drill hole. According to the invention, the inner tube (4) is secured in the anchor tube (2) by means of a snap-fit connecting arrangement (1).

Description

ι 2012339057 28 Aug 2017

ROCK ANCHOR

The invention relates to a rock anchor having an anchor tube and an inner tube arranged inside the anchor tube. Such a rock anchor is outfitted with an anchor tube and an inner tube arranged inside the anchor tube, and an extrudable hardenable material is arranged in the inner tube for the anchoring of the anchor tube in a drill hole. A rock anchor of this kind is known from DE 103 36 043 Al. This publication teaches a selfdrilling anchor which can be glued in the drill hole. The cartridge with the hardenable material needed for this is accommodated in the anchor tube, namely, in an inner tube arranged inside the anchor tube. The inner tube is held in the anchor tube by form fitting with a driving nut. The configuration with anchor tube and separate inner tube makes it possible to fabricate the parts needed for the load transfer and for the gluing at separate production facilities and assemble them only at the end of the process.

Other anchors having a hardenable material on their inside are known from WO 2010/140006 A2 and DE 10 2006 006 748 Al.

It is an object of the present invention to provide a rock anchor of this kind with improved reliability and/or diversity of application.

The present invention provides a rock anchor comprising: an anchor tube; an inner tube arranged inside the anchor tube; an extrudable hardenable material arranged in the inner tube for anchoring of the anchor tube in a drill hole; and an elastomer sleeve-shaped connection device arranged on an end of the inner tube, the anchor tube and connection piece together defining a snap-fit connection arrangement for securing the inner tube in the anchor tube.

Hardenable material, such as one based on diffusion effects, often only has a limited shelf life. When the shelf life runs out, it is generally required to separate the hardenable material from the steel in order to dispose of and possibly replace it. But the work of disassembly of the anchor required for this and also the loading of fresh hardenable material is often relatively time-consuming in the prior art. AH25(13528173 l):dah 2 2012339057 28 Aug 2017

According to the present invention, the inner tube with the hardenable material contained therein is secured in the anchor tube by means of a snap-fit connection arrangement. According to at least a preferred embodiment, such a snap-fit connection arrangement can be distinguished in particular in that, when joined together, at least one Joining piece is elastically deformed and then hooked by form fitting to the other joining piece. Since, with such a snap-fit connection piece, the elasticity of at least one of the joining pieces is used for the connection of the two joining pieces, the connection can be made and/or unmade especially easily and preferably toolless with it. A preferred embodiment may enable an especially easy loading of the anchor tube with the hardenable material and/or an especially easy disassembly of the hardenable material.

In particular, a simplified logistics can be provided by the invention, wherein the generally warehouse-stable but heavy outer tube and the glue cartridge having limited shelf life are brought together just shortly before the installation of the anchor in the rock. After the shelf life runs out, the cartridge can be taken out, preferably with simple means and in a brief time, and can thus be easily changed.

The hardenable material according to a preferred embodiment is especially an adhesive. It is preferably located in a cartridge arranged inside the inner tube, and the cartridge can be designed as a foilpack, for example. In particular, the hardenable material can have several components, for example a resin component and a curing component, which are present separately in the cartridge. For the mixing of the components of the hardenable material, the anchor preferably has at least one mixer, which can be arranged in particular on the inner tube.

The anchor may be a self-drilling anchor and accordingly it can have a drill head. In particular in the case of hard rock, however, the drilling can also be done with a separate drilling tool. A drill head on the anchor can then be omitted. The anchor tube, that is, the outer tube, preferably consists of metal, especially steel. The inner tube can consist of metal and/or plastic.

Especially advantageously, a connection piece is arranged on the inner tube at the end, and the snap-fit connection arrangement may be fashioned on the connection piece. According to this embodiment, the snap-fit connection arrangement/device is advisedly formed on a part which is separate from the inner tube, namely, the connection piece. This embodiment makes possible an especially effective snap-fit connection, without impairing the functionality of the inner tube. Preferably, the connection piece can consist of an elastomer, such as polyurethane, AH25(13528173_l):dah 3 2012339057 28 Aug 2017 and/or the inner tube of a metal. A connection piece made of elastomer not only can assure the functionality of the snap-fit connection but also advantageously fulfill sealing functions.

The connection piece is preferably sleeve shaped, i.e., fashioned as a connecting sleeve. It preferably has at least one axial passage, especially a central one, which enables in especially simple manner a feeding of a pressurizing agent into the inner tube for the purpose of extruding the hardenable material.

In particular, the snap-fit connection device may have at least one shoulder arranged on the anchor tube, and moreover the snap-fit connection device has at least one recess arranged on the connection piece, in which the shoulder is at least partly received. This provides an especially reliable snap-fit connection, especially when the anchor tube is more rigid than the connection piece. Especially preferably, the anchor tube has a driving nut, and the shoulder is arranged on the driving nut of the anchor tube. The driving nut can serve to connect a drilling apparatus for the rotational advancement of the anchor, preferably in form-fitting manner. For this, the driving nut can have, for example, an exterior polygon. The driving nut advisedly consists of a metallic material, preferably steel.

One preferred embodiment consists in the shoulder of the anchor tube or the driving nut being configured as an annular bulge, especially an uninterrupted annular bulge, and the connection piece having preferably at least one annular end stop, especially an uninterrupted annular end stop, against which the annular bulge lies. Thanks to the rotational symmetry of this arrangement, the snap-fit connection can always work the same here, regardless of the angular position of the connection piece relative to the outer tube, so that the mounting of the connection piece on the outer tube is further simplified.

In another advantageous embodiment, the connection piece projects at the end face beyond the anchor tube, especially beyond the driving nut of the anchor tube. Thanks to this projection, the connection piece can also perform a sealing function in especially easy manner with respect to an element that is axially press-fitted on the anchor tube, such as an injector which is axially press-fitted onto the anchor tube.

Furthermore, it is advisable for the connection piece to have a first sleevelike sealing region, which is shoved into the inner tube. In this way, an especially pressure-tight connection between inner tube and connection piece is made possible in especially easy manner, which is AH25( 13528173 l):dah 4 2012339057 28 Aug 2017 especially advantageous when high pressures prevail in the inner tube during the extruding of the hardenable material. It is especially advantageous for the first sleevelike sealing region to have at least one encircling sealing bulge on the outside. In this way, the sealing action between connection piece and inner tube can be even further improved.

Moreover, the connection piece may have a second sleevelike sealing region, which is arranged preferably coaxially to the first sealing region inside the first sealing region. The second sealing region can serve especially for a sealing against an injector needle. Thanks to two separate sealing regions being present, each sealing region can be optimized in its specific sealing action, without impairing the sealing action of the other sealing region.

Furthermore, advantageously, the connection piece may have a rear segment on which the snap-fit connection device is formed, and it has a front segment on which the first sealing region and/or the second sealing region is arranged. Thanks to the spatial separation of snap-fit connection device and sealing regions, an advantageous functional decoupling is accomplished. The two segments, however, are preferably made as a single piece in terms of manufacturing expense, especially being made of an elastomer.

Especially advisedly, moreover, the rear segment and the front segment may be joined together by connection webs. This accomplishes an especially simple and stable connection. In particular, through openings can be provided between the connection webs, for example, for delivering or removing of a fluid to and from an annular space formed between anchor tube and inner tube. Through these openings a fluid connection with said annular space can be produced in especially easy manner, for example, to deliver or remove flushing liquid.

Moreover, the snap-fit connection device preferably has a plurality of separate locking wedges, which are arranged on the connection piece. The separating of the individual locking wedges results in an especially good flexibility of the locking wedges, so that the mounting of the snapfit connection device is further simplified. In particular, the locking wedges can protect the connection piece from being pulled out from the anchor tube. AH25(13528173_l):dah 4a 2012339057 28 Aug 2017

Preferably, the locking wedges can be staggered with respect to the connection webs, looking in the circumferential direction of the connection piece, and/or one of said through openings is arranged beneath the locking wedge each time. This can further improve the flexibility of the locking wedges, so that the introducing of the connection piece into the outer tube is even further simplified.

In another advantageous embodiment, a reinforcement sleeve is arranged on the connection piece, especially on the first sleevelike sealing region. This reinforcement sleeve advisedly consists of a material having a higher strength than the material of the connection piece. It can prevent an unwanted deformation of the connection piece, especially the first sleevelike sealing region, which can potentially occur when high pressures are acting inside the connection piece during the extruding of the hardenable material and/or when the inner tube does not entirely surround the first sleevelike sealing region due to material tolerances, for example. The reinforcement sleeve can consist of acrylonitrile-butadiene-styrene (ABS), for example.

In particular, the anchor tube can have a first end with at least one exit opening for the hardenable material and a second end which can be coupled to a drilling apparatus for the rotary advancement of the rock anchor. The driving nut can be arranged at the second end, making possible the coupling of the drilling apparatus. The drill head, if present, is arranged at the first end.

In the context of the invention, by the axial direction can be meant in particular the longitudinal direction of the rock anchor and/or its anchor tube. By the radial direction can be meant in particular a direction which is perpendicular to the axial direction and which intersects the longitudinal axis of the rock anchor and/or its anchor tube. AH25(13528173_l):dah 4b 2012339057 28 Aug 2017 A preferred embodiment of the present invention will now be described, by way of an example only, with reference to the accompanying drawings wherein:

Fig. 1, a longitudinal section view of a rock anchor according to the invention;

Fig. 2, a longitudinal section detail view of the rock anchor from Fig. 1 in the region of the snapfit connection device; and

Fig. 3, a perspective view of the connection piece of Figures 1 and 2. A sample embodiment of a rock anchor according to the invention is shown in Fig. 1 to 3. The rock anchor has an anchor tube 2, which consists of a tube part 29 and a driving nut 20. The driving nut 20 is screwed onto an outer thread, which is formed on the tube part 29. The driving nut 20 has a polygon on its outside for a form-fitting, twist-free coupling of a drilling apparatus (not shown). At the first end 27 of the anchor tube 2, a drill head 24 with at least one cutting bit is arranged on the tube part 29 at the end face. At the second, opposite end 28 of the anchor tube 2 is situated its driving nut 20. In place of the drill head 24, a simple closure plug can also be provided, as long as the rock anchor does not have to be self-drilling.

Inside the anchor tube 2 there is an inner tube 4, which is open at both of its opposite end faces. Inside this inner tube 4, in turn, there is a cartridge 6 containing a hardenable material 7. Moreover, a mixer 8 and a piston 9 are arranged inside the inner tube 4. The mixer 8 is located at the first end 27, i.e., the side of the cartridge 6 facing the drill head 24, while the piston 9 is located at the side of the cartridge 6 facing the second end 28. AH25(13528173_l):dah

The cartridge 6 with the hardenable material 7, which can also be called the glue cartridge, can be hydraulically extruded into a drill hole after the rock anchor has been introduced. For this, the piston 9 is injected with extrusion water by an injector needle 100, shown only in Fig. 2, so that the piston 9 moves toward the mixer 8 and thereby presses the hardenable material 7 through the mixer and further on through at least one exit opening 26 provided in the drill head 24 to the outside.

At the second end 28, the inner tube 4 is axially fixed to the anchor tube 2 by a sleevelike connection piece 10, preferably made of an elastomer. The connection piece 10 has a front segment 13 with a first sleevelike sealing region 15. This first sleevelike sealing region 15 is shoved into the inner tube 4. The connection piece 10, moreover, has a rear segment 14, at which the connection piece 10 and thus the inner tube 4 are coupled to the anchor tube 2 via. a snap-fit connect!on device 1.

The snap-fit connection device 1 has a plurality of locking wedges 19, three in the example shown, on the connection piece 19. The locking wedges 19 are arranged in the form of a ring segment about the longitudinal axis of the rock anchor and/or the connection piece 10 and each have a wedge surface which faces the first end 27. The snap-fit connection device 1 moreover has a rear annular end stop 12 on the connection piece 10, and recesses 11 in the form of ring segments are formed between the locking wedges 19 and the rear annular end stop 12. The snap-fit connection device 1 moreover has an inwardly pointing shoulder 21 in the form of an annular bulge on the anchor tube 2, namely, on the driving nut 20, which is accommodated in the recesses 11 when the snap-fit connection is closed.

The rear segment 14 of the connection piece 10 is joined to the front segment 13 of the connection piece 10 by connection webs 18, three in the example depicted. The connection webs 18, as is especially evident in Fig. 2, project radially outward beyond the first sleevelike sealing region 15 and thus form an axial end stop for the inner tube 4, which is screwed onto the first sleevelike sealing region 15.

Through openings 17 in the form of ring segments are formed between the connection webs 18, which can serve to deliver flushing water into the annular space between inner tube 4 and tube part 29. As is especially evident in Fig. 3, the locking wedges 19 are arranged at an offset from the connection webs 18, so that each time one through opening 17 stands opposite the locking wedges 19. This produces an especially good flexibility of the locking wedges 19.

In the front segment 13, the connection piece 10 moreover has a second sleevelike sealing region 16, which is situated coaxially inside die first sleevelike sealing region 15, and which serves to seal off the connection piece 10 from the injector needle 100. Furthermore, the second sleevelike sealing region 16, which is set back inside the connection piece 10 relative to the first sleevelike sealing region 15, can also serve for coupling on a tool which can be used to pull the connection piece 10 out from the anchor tube 2. 5

As is especially evident in Fig. 2, the connection piece 10 in its rear segment 14 projects radially beyond the driving nut 20. Thus, the connection piece 10 can also serve as a seal against an injector which is press-fitted axially onto the driving nut 20.

For an even better seal between the first sleevelike sealing region 15 and the inner tube 4, the first sleevelike sealing region 15 has on its outside two axially spaced sealing bulges 81, which encircle the sealing region 15, and which lie against the inner tube 4 on the inside.

For radial rigidity, a reinforcement sleeve 83 is arranged on the front segment 13 of the connection piece 10, having a greater strength than the connection piece 10 itself. The connection piece 10 lies, preferably on both the inside and the outside, against the reinforcement sleeve 83. The reinforcement sleeve 83 has on the outside a radially projecting encircling ring 84, by which the reinforcement sleeve 83 is secured axially on the connection piece 10, especially on its connection webs 18.

When the rock anchor is assembled, the inner tube 4 with the cartridge 6 is shoved by means of the connection piece 10 into the anchor tube 2 and interlocks with the locking wedges 19. This snap-fit mechanism can also be reversible in design, so that the inner tube 4 with the cartridge 6 can also be disassembled once again in the reverse manner. 6

Claims

1. A rock anchor comprising: an anchor tube; an inner tube arranged inside the anchor tube; an extrudable hardenable material arranged in the inner tube for anchoring of the anchor tube in a drill hole; and an elastomer sleeve-shaped connection device arranged on an end of the inner tube, the anchor tube and connection piece together defining a snap-fit connection arrangement for securing the inner tube in the anchor tube.

2. A rock anchor according to claim 1, wherein the snap-fit connection arrangement has at least one shoulder arranged on the anchor tube and at least one recess arranged on the connection piece, in which the shoulder is at least partly received.

3. A rock anchor according to claim 2, wherein the anchor tube comprises a tube portion and a driving nut, the at least one shoulder being arranged on the driving nut.

4. A rock anchor according to either one of claims 2 and 3, wherein each shoulder is configured as an annular bulge; and the connection piece has at least one annular stop, against which the annular bulge lies.

5. A rock anchor according to one of claims 2 to 4, wherein the connection piece projects beyond the anchor tube.

6. A rock anchor according to one of claims 2 to 5, wherein the connection piece has a first sleeve-like sealing region, inserted into the inner tube, further wherein the first sleeve-like sealing region has at least one encircling sealing bulge located on an exterior thereof.

7. A rock anchor according to claim 6, wherein the connection piece has a second sleeve-like region arranged coaxially to the first sealing region inside the first sealing region.

8. A rock anchor according to either one of claims 6 and 7, wherein the connection piece has a rear segment on which the snap-fit connection arrangement is formed, and a front segment on which the first sealing region is arranged, further wherein the rear segment and the front segment are joined together by connection webs.

9. A rock anchor according to claim 8, wherein the snap-fit connection arrangement has a plurality of separate locking wedges, arranged on the connection piece, and which protect the connection piece from being pulled out from the anchor tube.

10. A rock anchor according to claim 9, wherein the locking wedges are staggered with respect to the connection webs, when viewed in a circumferential direction of the connection piece.

11. A rock anchor according to any one of claims 2 to 10, wherein a reinforcement sleeve is arranged on the connection piece.

12. A rock anchor according to any one of claims 1 to 11, wherein the anchor tube has a first end with at least one exit opening for the hardenable material and a second end coupleable to a drilling apparatus for rotary advancement of the rock anchor.