AU2007231788B2 - Retention Cap - Google Patents

Description

Regulation 3.2 ORIGINAL AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Invention Title: Rockbolt Adhesive Retention Cap and Inserter The invention is described in the following statement: 1 -2 "Rockbolt Adhesive Retention Cap and Inserter" Field of the Invention The present invention relates to the art of underground mining. More particularly, the invention relates to the reinforcing the roof of a mine tunnel. The modem art 5 of underground mining demands that many practices are undertaken to ensure safety within the mine. In particular, after a mine tunnel is extended, it is necessary to install reinforcement to the roof before mine workers are permitted to enter the portion that has been extended According to one current practice, a mine tunnel is typically extended by the use 10 of explosives for a length of approximately 3.5 metres. After the rock material has been dislodged by the explosive, it is removed by a machine known as a "bogger" which is a type of front-end loader having a loading arm which is of sufficient length to enable it to reach into the extended portion of the tunnel while the cabin portion of the vehicle remains in the portion of the tunnel which is protected. Once 15 the rock material has been cleared it is then necessary to reinforce the roof of the newly extended portion of the mine tunnel by applying rock bolts at spaced intervals across the area of roof of the extended portion of the mine. The application of the rock bolts can be associated with a mesh which is fixed to the surface by at least some of the rock bolts. It is the method of installing such rock 20 bolts to which this invention specifically relates. Background Art The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part 25 of the common general knowledge as at the priority date of the application.

-3 According to one current practice of roof reinforcement, the mesh is finally retained to the roof by a series of spaced support plates which are fixed to the roof of the tunnel and which engage the mesh to hold it against the roof. The plates are fixed to the roof of the tunnel by rock bolts which are known as "resin 5 anchors" or "chemical bolts" and which require a hole to be drilled into the roof in order that they can be inserted into holes formed in the rock of the rooft Resin anchors comprise metal bolts which when in position are encased in an epoxy resin within a drill hole where the epoxy resin retains the metal bolt in position and protects the bolt from the corrosive influences within the drill hole. The epoxy resin 10 is supplied in cylindrical adhesive cartridges which comprise both of the two components separated from each other by a barrier. In use the adhesive cartridges are inserted into holes drilled in the roof and the metal bolt is then inserted into the hole and is caused to rotate while passing though the adhesive cartridge. The insertion and rotation of the bolt through the adhesive cartridges 15 breaks the barrier within the adhesive cartridge and the adhesive cartridge and causes the epoxy resin components to fill the inner portion at least of the space between the bolt and the borehole and react in order that it hardens whereby the metal bolts are retained in the hole by the epoxy resin which can also serve to protect the bolts from the corrosive effects of water which may be present in the 20 rock. A variety of types of epoxy having differing strengths and setting times are used. In order to install the resin anchors, it is necessary to first drill the hole which can typically have a diameter of the order of 32 mm and a length of the order of 2.5 metres. The holes are drilled by rock drills mounted on a vehicle known as a 25 "jumbo" which comprises a vehicle the front of which supports at least one hydraulically driven, extendable arm a "boom" which supports a drill which is used to drill the holes for the resin anchors. The arms of the jumbo enable the holes to be drilled in the extended portion of the mine tunnel without the main part of the vehicle which incorporates the cabin in which the operator is seated, having to 30 enter that extended portion. Once the holes have been drilled the adhesive -4 cartridge is manually inserted into hole by a mineworker accommodated within a protective cage supported from another vehicle which has a boom which can extend into the unprotected portion of the tunnel. Therefore for safety reasons it is necessary to initially fix the mesh to the roof temporarily to provide some 5 protection for the mineworker who is required to insert the epoxy resin cartridges. A solution to the problem of having a mine worker located in an unsafe environment has been proposed in patent specifications AU2002248972 and 2004216586. According to the prior disclosures the adhesive cartridge is able to be inserted into the boreholes remotely using an inserter which is supported from 10 the "jumbo" whereby the inserter supports the adhesive cartridge and can be inserted into the borehole and then removed leaving the adhesive cartridge in position within the bore hole. In this regard the retention of the adhesive cartridge in the borehole is effected by means of a retention cap. The discussion throughout this specification, of the background and prior art to the 15 invention is intended only to facilitate an understanding of the present invention. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia and the world as at the priority date of the application. Disclosure of the Invention 20 Throughout the specification and claims, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Accordingly, one aspect the present invention resides in a retention cap intended 25 in use to retain an adhesive cartridge in a bore hole, the cap comprising a substantially cylindrical body which defines a passage which opens to both end of the body, wherein the passage is dimensioned such that in use one end of the -5 passage is receivable over an end portion of the adhesive cartridge to locate the end portion within the passage, the passage being configured to grip the end portion, the cap further comprising retention means which extends laterally from the body, the retention means being configured to enable the retention cap to be 5 inserted into a borehole but to restrain the retention cap from being withdrawn from the bore hole. According to a preferred feature of the invention a barrier extends across of the passage proximate the other end to prevent the end of the cartridge extending beyond the other end. 10 According to a preferred feature of the invention the retention means comprises a laterally directed formation extending radially outwardly from the body. According to a preferred feature of the invention the formation is adapted to be displaceable in a radial direction to thereby engage the wall of the hole on a net withdrawal force being applied to the cap. According to a preferred feature of the invention 15 the formation is in use able to be resiliently deformed to enable insertion of the cap into the hole and to retain the cap within the hole after insertion. According one embodiment of the invention the formation comprises a plurality of resilient wing-like elements extending outwardly from the body. According to another embodiment of the invention the formation comprises a substantially continuous 20 skirt formed to extend laterally from the retention cap. According to another embodiment of the invention the formation comprises a set of elongate elements supported from the body at angularly spaced intervals around the body and extending substantially radially from the body. According to a preferred feature of the embodiment the elongate elements are angled with respect to the central axis 25 of the body to be inclined away from the outer end of the body According to a preferred feature of the invention the passage is tapered to enhance retention of the adhesive cartridge to the cap. According to a preferred feature of the invention the passage is tapered inwardly from the inner end towards the outer end.

-6 According to a preferred feature of the invention a plurality of ribs are provided on the surface of the passage to enhance retention of the adhesive cartridge to the cap. According to a preferred feature of the invention the ribs extend along at least a portion of the length of the passage. According to a preferred feature of 5 the invention the ribs extend around at least a portion of the interior of the passage. According to a preferred feature of the invention the retention means is located proximate the one end of the body but is spaced from the one end. According to another embodiment of the invention the retention means is located intermediate 10 of the ends of the body. According to a preferred feature of the invention in use the cap is intended in use to cooperate with an adhesive cartridge inserter comprising a hollow tube portion having an opening at one end, the interior region of the tube portion being adapted to receive said adhesive cartridge, and wherein the one end of the body 15 is dimensioned to be receivable in the one end of the inserter. According to a preferred feature of the invention the inner end is frictionally engagable with the one end of the inserter. According to another aspect the invention resides in a rock bolt adhesive cartridge inserter intended in use to enable insertion of a cartridge into a rock bolt hole 20 drilled in a rock wall, said inserter comprising a tube and a retention cap, the tube having an opening at each end, the tube having an external diameter to enable the inserter to be closely received in the rock bolt hole, the internal diameter of the tube dimensioned to slidably receive a cartridge with one end of the cartridge located proximate one end, the other end being configured to in use to be able to 25 be fixed to a received on a support such that the tube is rigidly supported from the support, the tube having a length at least equal to the depth of the rock bolt hole and the retention cap intended in use to retain the adhesive cartridge in the bore hole, the retention cap comprising a retention cap of the form as described above.

-7 According to a preferred feature of the invention the one end of the tube is of a reduced external diameter. According to a preferred feature of the invention the internal bore of the tube is of substantially constant diameter throughout its length. 5 According to a preferred feature of the invention the tube is variable in length. According to a preferred feature of the invention the support comprises the "shank" of a "jumbo" and wherein in use the "jumbo" is able to locate support such that the one end of the tube is located at the entry of the rock bolt hole with the tube aligned with the rock bolt hole, and then insert and withdraw the tube into 10 and from the rock bolt hole. The invention will be more fully understood in the light of the following description of several specific embodiments. Brief Description of the Drawings The description is made with reference to the accompanying drawing of which: 15 Figure I is a side orthogonal view of adhesive cartridge inserter and a retention cap according to the first embodiment; Figure 2 is a sectional elevation of a retention cap according to the first embodiment; Figure 3 is a sectional view of a cartridge inserter and retention cap in accordance 20 with the first embodiment when inserted into a bore hole; Figure 4 is an isometric view of a retention cap according to the second embodiment of the invention; -8 Figure 5 is a sectional elevation of a retention cap according to the third embodiment; Figure 6 is an isometric view of a retention cap according to the third embodiment of the invention; and 5 Figure 7 is an isometric view of a retention cap according to the fourth embodiment of the invention; Detailed Description of Specific Embodiment The first embodiment of the invention as shown at Figures I to 3 comprises a retention cap 11 which is intended to be used with an inserter 13 to enable the 10 remote insertion of an adhesive cartridge into a drill hole. The inserter 13 comprises a cylindrical tube portion having an opening 15 and a support portion 17 disposed at the other end and integral to the tube 20 portion. The support portion 13 has an external thread and is intended in use to be supported from the boom (not shown) of a "jumbo". The support is provided by a threaded drifter 19 15 which is provided with the boom and the support portion is mounted to the drifter through an internally threaded tubular adapter 21. The tube portion 11 is dimensioned receive an adhesive cartridge 23. The tube portion 11 is also dimensioned to be insertable within a bore hole drilled in that the external diameter of the tube portion 11 is to be slightly smaller than the diameter of the 20 bore hole. In use, the cartridge inserter 13 is supported by a drifter 19 on one boom of a jumbo. An adhesive cartridge 23 is inserted into the tube portion and the inserter is used to locate the adhesive cartridge in the borehole. The adhesive cartridge 23 accommodates a two component epoxy resin where the two components are 25 separated by a barrier. A retention cap 25 as shown at Figures 1 to 4 is applied to one end of the cartridge before it is inserted into the tube'portion such that the retention cap 25 is supported from the outer end of the tube portion.

-9 The retention cap as shown at Figures 1 to 4 is formed of a suitable plastics material and comprises a cylindrical body 27 which is tubular to define a passage 29 which opens to both ends of the body. One end portion of the adhesive cartridge is received through one end of the body to be accommodated within the 5 passage. The exterior of the body supports retaining means comprising a set of elongate elements 31 located at spaced intervals around the body and which extend radially from the body. The elongate elements are angled relative to the central axis of the body to be inclined away from the outer end of the body. The retention means is located at an intermediate position along the length of the 10 body. The inner most portion 33 of the body is dimensioned such that it is snugly received in the inner end of the tube portion of the inserter 13 In use, the retention cap 25 is inserted over the outer end of the adhesive cartridge such that the end portion is received in the passage and is gripped thereby. The adhesive cartridge is then inserted into the tube portion of the 15 inserter such that the lower [portion of the body is received in the outer end of the tube portion and the inserter is then inserted into the borehole. As result of such insertion elongate elements 31 are bent or pressed to lie parallel with the axis of the tube while the residual resilience in the arms urges the arms radially outwardly to some extent. During insertion, the elongate elements provide little hindrance to 20 the insertion of the retention means. Once the tube portion has been inserted to the desired depth in the bore hole for location of the adhesive cartridge within the bore hole the inserter is then withdrawn. While the frictional forces between the inserter 13 and the adhesive cartridge, together with gravity applies a net withdrawal force to the retention cap 25, it is held in place due to the interaction 25 between the retention cap 25 and the sides of the borehole. This interaction is as a result of the residual resilience in the elongate elements 39, which serves to bias the elongate elements outwardly to engage the wall of the hole, thereby preventing the retention cap 25 and adhesive cartridge retained thereby from being withdrawn from the hole with the inserter.

-10 In operation once a hole has been drilled in the conventional manner, the jumbo operator can maneuver the arm of the jumbo supporting the inserter to align the inserter with the hole and then insert the inserter 13 into the hole to the required distance. Thereafter, the inserter is withdrawn from the hole and the retention cap 5 25 together with the adhesive cartridge remain in position within the hole. The metal rock bolt is then inserted into the hole in the normal manner. The retention cap of the second embodiment is similar to that of the first embodiment but as shown at Figure 4 the elongate elements 39 are located at spaced positions around and along the body. 10 The retention cap of the third embodiment is similar to that of the first embodiment but as shown at Figures 5 and 6 the retention means comprises an annular skirt 41 which is formed with angularly spaced slots 43. The retention cap of the fourth embodiment is similar to that of the third embodiment but as shown at Figure 7 the slots 43 are formed as rebates 45, 15 The present invention is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only. Functionally equivalent products, formulations and methods are clearly within the scope of the invention as described herein.

Claims (25)

1. A retention cap intended in use to retain an adhesive cartridge in a bore hole, the cap comprising a substantially cylindrical body which defines a passage which opens to both end of the body, wherein the passage is 5 dimensioned such that in use one end of the passage is receivable over an end portion of the adhesive cartridge to locate the end portion within the passage, the passage being configured to grip the end portion, the cap further comprising retention means which extends laterally from the body, the retention means being configured to enable the retention cap to be 10 inserted into a borehole but to restrain the retention cap from being withdrawn from the bore hole.

2. A cap as claimed in claim I or 2 wherein a barrier extends across the passage proximate the other end to prevent the end of the cartridge extending beyond the other end. 15

3. A cap as claimed in claim I or 2 wherein the retention means comprises a laterally directed formation extending radially outwardly from the body.

4. A cap as claimed in claim 3 wherein the formation is adapted to be displaceable in a radial direction to thereby engage the wall of the hole on a net withdrawal force being applied to the cap. 20

5. A cap as claimed in claim 3 or 4 wherein the formation is in use able to be resiliently deformed to enable insertion of the cap into the hole and to retain the cap within the hole after insertion.

6. A cap as claimed in any one of claims 3 to 6 wherein the formation comprises a plurality of resilient wing-like elements extending outwardly 25 from the body. - 12

7. A cap as claimed in any one of claims 3 to S wherein the formation comprises a substantially continuous skirt formed to extend laterally from the retention cap.

8. A cap as claimed in any one of claims 3 to 6 wherein the formation 5 comprises a set of elongate elements supported from the body at angularly spaced intervals around the body and extending substantially radially from the body.

9. A cap as claimed in claim 8 wherein the elongate elements are angled with respect to the central axis of the body to be inclined away from the outer 10 end of the body

10. A cap as claimed in any one of the previous claims wherein the passage is tapered to enhance retention of the adhesive cartridge to the cap.

11. A cap as claimed in claim 10 wherein the passage is tapered inwardly from the inner end towards the outer end 15

12..A cap as claimed in any one of the preceding claims wherein a plurality of ribs are provided on the surface of the passage to enhance retention of the adhesive cartridge to the cap.

13. A cap as claimed in claim 12 wherein the ribs extend along at least a portion of the length of the passage. 20

14.A cap as claimed in claim 10 wherein the ribs extend around at least a portion of the interior of the passage.

15.A retention cap as claimed in any one of the preceding claims wherein in use the cap is intended in use to cooperate with an adhesive cartridge inserter comprising a hollow tube portion having an opening at one end, the -13 interior region of the tube portion being adapted to receive said adhesive cartridge, and wherein the one end of the body is dimensioned to be receivable in the one end of the inserter.

16.The retention cap as claimed in claim 15 wherein the one end of the body 5 is frictionally engagable with the one end of the inserter.

17.The retention cap as claimed in any one of the preceding claims wherein the retention means is located proximate the one end of the body but is spaced from the one end.

18.The retention cap as claimed in any one of claims I to 16 as dependant 10 from claim wherein the retention means is located intermediate of the ends of the body.

19.A retention cap substantially as herein described with reference to the accompanying drawings.

20.A rock bolt adhesive cartridge inserter intended in use to enable insertion 15 of a cartridge into a rock bolt hole drilled in a rock wall, said inserter comprising a tube and a retention cap, the tube having an opening at each end, the tube having an external diameter to enable the inserter to be closely received in the rock bolt hole, the internal diameter of the tube dimensioned to slidably receive a cartridge with one end of the cartridge 20 located proximate one end, the other end being configured to in use to be able to be fixed to a received on a support such that the tube is rigidly supported from the support, the tube having a length at least equal to the depth of the rock bolt hole and the retention cap intended in use to retain the adhesive cartridge in the bore hole, the retention cap comprising a 25 retention cap as claimed at any one of the preceding claims.. - 14

21 .A cartridge inserter as claimed at claim 20 wherein the one end of the tube is of a reduced external diameter.

22.A cartridge inserter as claimed in any one of claims 20 or 21 wherein the internal bore of the tube is of substantially constant diameter throughout its 5 length.

23. A cartridge inserter as claimed in any one of claims 20 to 22 wherein the tube is variable in length.

24.A cartridge inserter as claimed in any one of claims 20 to 23 wherein the support comprises the "shank" of a "jumbo" and wherein in use the "jumbo' 10 is able to locate support such that the one end of the tube is located at the entry of the rock bolt hole with the tube aligned with the rock bolt hole, and then insert and withdraw the tube into and from the rock bolt hole.

25.A cartridge inserter substantially as herein described with reference to the accompanying drawings. 15