AU2008246268B2

AU2008246268B2 - Self-boring bonding anchor

Info

Publication number: AU2008246268B2
Application number: AU2008246268A
Authority: AU
Inventors: Michael Bayerl; Kay Heemann; Wolfgang Ludwig; Kolja Wieczorek
Original assignee: Hilti AG
Current assignee: Hilti AG
Priority date: 2007-11-30
Filing date: 2008-11-20
Publication date: 2011-06-09
Anticipated expiration: 2028-11-20
Also published as: CN101446202A; AU2008246268A1; US20090142142A1; ZA200810155B; NZ572920A; EP2065559A2; DE102007057763A1

Description

- 1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant/s: Hilti AG Actual Inventor/s: Michael Bayer and Wolfgang Ludwig and Kolja Wieczorek and Kay Heemann Address for Service is: SHELSTON IP 60 Margaret Street Telephone No: (02) 9777 1111 SYDNEY NSW 2000 Facsimile No. (02) 9241 4666 CCN: 3710000352 Attorney Code: SW Invention Title: SELF-BORING BONDING ANCHOR The following statement is a full description of this invention, including the best method of performing it known to me/us: File: 59895AUP00 2 Self-boring bonding anchor Field of the Invention The present invention relates to a self-boring bonding anchor for mining and 5 tunnel construction. Background of the Invention Any discussion of the prior art throughout the specification should in no way be 10 considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. Such self-boring bonding anchors are used in mining and tunnel construction, where they serve the purpose of securing hollow spaces, like tunnels, galleries and the like. When hollow spaces are produced, the mechanical properties and, 15 in particular, the bearing capacity of the rock strata is reduced. These rock strata are anchored by means of the bonding anchor to further remote, undamaged rock strata and thus secured on them. The setting process in the case of known bonding anchors is carried out in two 20 steps. In the first step the bonding anchor is bored into the substratum by means of the boring equipment. The rock is disintegrated and comminuted by the boring head of the boring anchor at its end which is in the direction of boring. This disintegrated and comminuted rock is transported away through the outlet openings provided on the boring head and the intermediate space between the 25 wall of the bore and the outer circumference of the bonding anchor. In the case of wet boring, water is introduced in the direction of setting and the disintegrated and comminuted rock is flushed out. In a second step, a chemical substance is compressed at the end of the bonding anchor which is opposite the direction of setting by means of a squeezing mechanism in the direction of the bottom of the 30 bored hole, whereby the mortar situated in the bonding anchor is moved out from the bonding anchor and the boring head through the outlet openings into the bored hole and distributed along the intermediate space between the wall of the bore and the outer circumference of the anchor tube.

3 From DE 103 36 043 Al, a self-boring bonding anchor of the generic type is known that has an anchor tube with a first end, on which a boring head is provided, and a free second end. An inner tube is provided in the anchor tube, whereby an intermediate space is provided between the inner tube and the 5 anchor tube, extending at least in some areas along a longitudinal axis of the anchor tube and constructed as an annular gap. In the case of wet boring, this makes the introduction of water possible. For this purpose outlet openings are provided on the boring head, the outlet openings being connected with the first intermediate space and can be connected with an internal space of the inner 10 tube. In the internal space of the inner tube a extrudable substance, packed in a foil bag, is provided, the substance able to be delivered through the outlet openings in the boring head. At the second free end of the anchor tube a further first opening is provided on the longitudinal axis, the opening communicating with the first intermediate space and with the internal space. 15 It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. Summary of the Invention 20 According to the invention there is provided a self-boring bonding anchor for mining and tunnel construction with an anchor tube defining the longitudinal axis, said anchor tube having a first end with a boring head and a free second end, with an inner tube provided in the anchor tube, the inner tube having an internal 25 space to accommodate a squeezable substance, with an intermediate space extending between the anchor tube and the inner tube, with a first axial, relative to the longitudinal axis, axial opening in the region of the free second end, said axial opening communicating with the internal space in the inner tube, and with at least one outlet opening in the region of the boring head, wherein in the region of 30 the free second end at least one second, relative to the longitudinal axis, radial opening is provided that via the intermediate space is in connection with the at least one outlet opening.

4 By virtue of this separation of the accesses to the intermediate space, on the one hand, and to the internal space of the inner tube, on the other, a crossing of the supply of flushing water and of the supply of the extrudable medium is prevented. Separate supply lines to the first axial opening and to the at least one radial 5 second opening may be provided, by virtue of which conventional boring motors with central flushing water supply may be used, wherein no second circuit for the high-pressure extrudable medium is provided. Advantageously, two oppositely situated radial second openings are provided, by 10 virtue of which an adequate supply of flushing water is ensured even with a rotating bonding anchor. It is a further advantage when the at least one radial second opening is provided in the anchor tube, by virtue of which the radial second opening is easily 15 accessible from the outside and they directly discharge into the intermediate space. It is a further benefit when the at least one radial second opening is at an axial distance from the free second end, the distance being between 0.5-2 times that of 20 the diameter of the anchor tube. The result of this is that common supply systems of flushing water can be used with the simultaneous use of common boring motors with central water supply. Brief Description of the Drawings 25 A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a longitudinal section of a self-boring bonding anchor according 30 to an embodiment of the invention..

5 Preferred Embodiment of the Invention In the figure a self-boring bonding anchor 10 according to the invention is illustrated, that has an anchor tube 11 from steel and an inner tube 15 provided 5 therein, for example from steel or plastic material. In an internal space 16 of the inner tube 15 a substance 30, that is packed in a foil bag 31 and can be squeezed out, is provided as a single- or multi-component chemical compound substance. The anchor tube 11 has a first end 12 with an inserted boring head 13 and a free, second end 14 and defines a longitudinal axis L of the bonding anchor 10 10. The inner tube 15 is held radially and axially in the anchor tube 11 by means of a first centring means 14 and a second centring means 25 and at the same time guided coaxially with the longitudinal axis L. In the region of the free second end 14 of the anchor tube 11 a first, relative to 15 the longitudinal axis L, axial opening 18 is provided, that communicates with the internal space 16 in the inner tube 15. A pressure medium (first arrow 21), like water for example, can be pressed into the internal space 16 of the inner tube 15 through this axially first opening 18, by virtue of which the foil bag 31, provided in the inner tube 15, is squeezed out by a squeezing element 33 guided between 20 the first axial opening 18 and the foil bag 31. By doing so the substance 30 held in the foil bag 31 is guided through a mixing element 32, wherein the components of the substance 30 are blended with one another. The thoroughly mixed substance 30 can then exit from the inner tube 15 and the mixing body 32 in the direction of the second arrow 22 into the boring head 13 and further into the 25 external space of the bonding anchor 10 through the outlet openings 20 provided in the boring head 13. The inner tube 15 is positioned in the anchor tube 11 by the centring means 24, 25 in such a manner, that an intermediate space 17 in the form of an annular gap 30 is present between the inner tube 15 and the anchor tube 11. In the region of the free second end 14 two oppositely situated, relative to the longitudinal axis L, radial second openings 19 are provided in the anchor tube 11, which are connected with the outlet openings 20 in the boring head via the intermediate space 17. The intermediate space 17 makes a supply of water possible in the 6 case of wet boring, the water being able to be delivered via the radial second openings 19 in the intermediate space 17 (third arrow 23) up to the boring head 13 and finally through the outlet openings 20 to the external space. 5 The radial second openings 19 are preferably at an axial distance A from the free second end 14 of the anchor tube 11, the distance A being 0.5-2 times the diameter D of the anchor tube 11. The outlet openings 20, the intermediate space 17 and the radial second 10 openings can be used, of course, also for the evacuation of the quarry dust when the method used is for dry boring. Though the present invention was shown and described with references to the preferred embodiment, such is merely illustrative of the present invention and 15 is not to be construed as a limitation thereof and various modifications of the present invention will be apparent to those skilled in the art. It is therefore not intended that the present invention be limited to the disclosed embodiment or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by 20 the appended claims.

Claims

1. A self-boring bonding anchor for mining and tunnel construction with an anchor tube defining the longitudinal axis, said anchor tube having a first end with a 5 boring head and a free second end, with an inner tube provided in the anchor tube, the inner tube having an internal space to accommodate a squeezable substance, with an intermediate space extending between the anchor tube and the inner tube, with a first axial, relative to the longitudinal axis, axial opening in the region of the free second end, said axial opening communicating with 10 the internal space in the inner tube, and with at least one outlet opening in the region of the boring head, wherein in the region of the free second end at least one second, relative to the longitudinal axis, radial opening is provided that via the intermediate space is in connection with the at least one outlet opening. 15

2. A self-boring bonding anchor according to claim 1, wherein two oppositely situated radial second openings are provided.

3. A self-boring bonding anchor according to claim 1 or 2, wherein the at least one radial second opening is provided in the anchor tube. 20

4. A self-boring bonding anchor according to any one of claims 1 to 3, wherein the at least one radial second opening is at a distance from the free second end, the distance being between 0.5-2 times that of the diameter of the anchor tube. 25

5. A self-boring bonding anchor for mining and tunnel construction substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying drawings and/or examples.