AU2012100916A4 - Rock bolt - Google Patents

Abstract

Abstract A rock bolt assembly having an elongate shaft and a nut having an internal cavity extending therethrough, the nut s including at least one channel configured for introducing grout to the assembly, the channel being located intermediate the threaded internal surface and an external surface of the nut. 3416212_1 (GHMatters) P90463.AU 19/06/12 tLL

Description

AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION Innovation Patent Applicantss: FCI Holdings Delaware, Inc. Invention Title: ROCK BOLT The following statement is a full description of this invention, including the best method for performing it known to me/us: IP Australia 19 JUN 2012 RECEIVED |PL -2 ROCK BOLT ASSEMBLY TECHNICAL FIELD 5 The present disclosure relates to rock strata applications employing rock bolt assemblies to provide roof, wall and floor support. The rock bolt assembly is suitable for hard rock 10 applications, underground tunnelling applications such as those in civil structures and hard rock mines, as well as for softer strata, such as that often found in coal mines. It is to be appreciated that the term "rock" as used in the specification is to be given a broad meaning to cover is these applications. BACKGROUND Roof and wall support is vital in mining and tunnelling 20 operations. Mine and tunnel walls and roofs consist of rock strata, which must be reinforced to prevent or reduce the possibility of collapse. Rock bolts are widely used in consolidating the rock strata by securing a rock bolt in a bore within the rock strata and placing tension on 25 the rock bolt. This tension allows consolidation of the strata by placing the strata in compression. When securing the rock bolt in the bore hole, bonding material may be utilised to adhesively unite the rock 30 strata and firmly hold the rock bolt within the bore hole. In one form of anchoring, grout, such as cement grout, is inserted into the bore hole after positioning the rock bolt in the bore hole. Cement grouts offer corrosion 3416212_1 (GHMatters) P90463.AU 19106/12 - 3 protection to uncoated steel rock bolts by maintaining a high pH about the rock bolt. Further, in protecting a rock bolt from corrosion it is 5 known to use an impermeable sleeve such as a plastic sleeve to prevent water contact with the rock bolt causing corrosion. The sleeve is flexible to maintain a water impermeable barrier in situations where the ground moves. 10 A combination of a flexible sleeve and cement grout material allows for further protection as the sleeve protects the rock bolt if the brittle cement grout cracks. is SUMMARY OF THE DISCLOSURE Disclosed in some forms is a rock bolt assembly comprising a rock bolt and a nut. Disclosed in some forms is a sleeve for a rock bolt assembly. Disclosed in some forms is a 20 rock bolt assembly comprising a rock bolt and a sleeve. In at least one form, disclosed is a rock bolt assembly having an elongate shaft configured to be at least partially located in a bore formed in a rock substrate and 25 a nut having an internal cavity extending therethrough, the internal cavity having a threaded internal surface, the nut including at least one channel configured for introducing grout to the assembly, the channel being located intermediate the threaded internal surface and an 30 external surface of the nut. In at least one form, disclosed is a nut for a rock bolt assembly having an elongate shaft configured to be at 3416212_1 (GHMatters) P90463.AU 1sioni - 4 least partially located in a bore formed in a rock substrate, the nut having an internal cavity extending therethrough, the internal cavity having a threaded internal surface, at least one channel configured for 5 introducing grout to the rock bolt assembly, the channel being located intermediate the threaded internal surface and an external surface of the nut. In at least one form disclosed is a sleeve for a rock bolt io assembly having a rock bolt shaft, the sleeve being configured to be positioned about the rock bolt assembly and comprising an elongate tubular member with an external helical thread and a skirt threadedly connected with the tubular member. is The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments and features will become apparent by reference to the drawings and the 20 following detailed description. Furthermore, in the specification, the term "point of sale" is used in a general sense to describe systems that are designed to display products for selection by a user, regardless of whether those products are for sale or may be freely 25 accessible. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of a rock bolt assembly of 30 one embodiment of the disclosure; Fig. 2 is a perspective view of a nut of one embodiment of 3416212_1 (GHMatters) P90463.AU 19/06/12 -5 the disclosure; Fig. 3 is a rear perspective view of the nut of Fig. 2; 5 Fig. 4 is a perspective view of one embodiment of a sleeve of the present disclosure; Fig. 5 is a cross sectional view of a portion of the sleeve of Fig. 4; 10 Fig. 6 is a side view of a portion of the sleeve of Fig. 4; and, Fig. 7 is a cross sectional view of one embodiment of a is sleeve and rock bolt assembly of the present disclosure. DETAILED DESCRIPTION In the following detailed description, reference is made 20 to accompanying drawings which form a part of the detailed description. The illustrative embodiments described in the detailed description, depicted in the drawings and defined in the claims, are not intended to be limiting. Other embodiments may be utilised and other changes may be made 2S without departing from the spirit or scope of the subject matter presented. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated and designed in a wide 30 variety of different configurations, all of which are contemplated in this disclosure. This disclosure is directly generally to rock bolt 3416212_ 1 (GHMatters) P90463.AU 19/0o/12 - 6 assemblies and nuts and sleeves suitable for rock bolt assemblies. Disclosed are embodiments of a rock bolt assembly, a nut 5 and a sleeve. In some forms, disclosed is a rock bolt assembly having an elongate shaft configured to be at least partially located in a bore formed in a rock substrate and a nut having an internal cavity extending therethrough, the internal cavity having a threaded 10 internal surface, the nut including at least one channel configured for introducing grout to the assembly, the channel being located intermediate the threaded internal surface and an external surface of the nut. is In some forms the nut extends from a leading end to a trailing end and the trailing end includes a planar surface, the channels being positioned such that they extend from the planar surface. 20 In some forms the external surface comprises a dome. In some forms the dome surrounds the planar surface. In some forms the or each channel extends adjacent the 25 internal cavity. In some forms the or each channel is configured such that it extends substantially parallel to the internal cavity. 30 In some forms the or each channel comprises a plurality of channels spaced apart about the internal cavity. 3416212_1 (GHMatters) P90463.AU 19/612 -7 Disclosed in some embodiments is a nut for a rock bolt assembly having an elongate shaft configured to be at least partially located in a bore formed in a rock substrate, the nut having an internal cavity extending 5 therethrough, the internal cavity having a threaded internal surface, at least one channel configured for introducing grout to the rock bolt assembly, the channel being located intermediate the threaded internal surface and an external surface of the nut. 10 In some forms the nut extends from a leading end to a trailing end and the trailing end includes a planar surface, the channels being positioned such that they extend from the planar surface. 15 Disclosed in some embodiments is a sleeve for a rock bolt assembly having a rock bolt shaft, the sleeve being configured to be positioned about the rock bolt assembly 20 and comprising an elongate tubular member having an external profile in the form of a continuous protrusion. In some forms the continuous protrusion is helical. 25 In some forms the protrusion is in the form of a helical ridge. In some forms the helical ridge has an amplitude of between 4 mm and 8 mm. 30 In some forms the sleeve has a skirt threadedly connected with the tubular member. 3416212_ 1 (GHMatters) P90463.AU 19106/12 -8 In further embodiments disclosed is a rock bolt assembly comprising a rock bolt shaft configured to be at least partially located in a bore formed in a rock substrate, and a sleeve configured to be located in use about the s rock bolt shaft, the sleeve including an external profile in the form of a continuous helical protrusion, the shaft and sleeve defining an intermediate cavity therebetween. In some forms the intermediate cavity is annular. 10 In some forms the assembly further comprises a nut, having an internal nut cavity extending therethrough and at least one channel configured for introducing grout to the rock bolt assembly, the channel being located intermediate the 15 threaded internal surface and an external surface of the nut, the channel and the intermediate cavity being in fluid communication with one another. In some forms the sleeve further comprises a skirt 20 extending from the sleeve and configured to be positioned in use over a portion of the nut such that the channel feeds into the skirt. As illustrated in the Figs, some illustrative embodiments of a rock bolt assembly and a nut for a rock bolt assembly 25 allow for an enhanced grout flow pathway. Some illustrative embodiments of a sleeve design allow for smooth grout flow and improved bond strength. Some embodiments of a grout adaptor allow for remote attachment of the grout adaptor, an enhanced seal between the nut and 30 the grout adaptor, and improved safety for operators. Referring to the Figs, disclosed is a rock bolt 1 comprising an elongated shaft 2 extending from a proximal 3416212_1 (GHMatters) P90463.AU 19106/12 - 9 end 3 to a distal end 4. The rock bolt 1 is adapted to be inserted into a bore hole within a rock formation to reinforce and apply tension to the rock formation. 5 The rock bolt assembly includes a nut 7 which is configured to place tension upon the rock bolt shaft 2. The nut is configured to work with a plate 8, which in use is adapted to abut the rock surface to maintain the rock bolt in position within the bore hole. The nut 7 io comprises a leading end 10 and a trailing end 11. In the illustrated form, the leading end is in the form of a dome shaped surface. An interior cavity extends through the nut 7. The interior cavity 13 includes a helical thread 14 on its interior surface 15. The interior cavity 13 is extends from the leading end to the trailing end. The trailing end 11 includes a profiled surface 17. The nut 7 further includes a plurality of channels 19 which extend from the leading end 10 to the trailing end 20 11. The plurality of channels 19 are spaced apart about the interior cavity 13 and extend such that they are substantially parallel to the interior cavity 13. The channels 19 are elongate and extend perpendicularly to the helical thread 14. In the illustrated form the channels 25 comprise three channels however it will be clear to a person skilled in the art that any number of channels would be useable for this application. The channels 19 are adapted to allow grout to be directed 30 about the rock bolt shaft 2. Grout can be pumped through the channels 19 such that the grout flow pathway is perpendicular to or substantially perpendicular to the helical thread of the interior cavity. In use, grout is 3416212_1 (GHMatters) P90463.AU 19/06/12 - 10 pumped to the distal end 4 of the rock bolt and allowed to fill the rock bore towards the plate 8 to complete a column of grout in the space between the bore hole wall and the rock bolt shaft 2. 5 Referring to Figs 4-6, disclosed is a grout sleeve 20 which is configured to be positioned about the rock bolt shaft 2 to prevent ground water contact with the steel of the rock bolt. The sleeve 20 extends from a leading end 10 21 to a trailing end 22. As illustrated in Fig 4, the grout sleeve includes a skirt cup 24 in the form of a bell shaped skirt which is threadedly connected with grout sleeve 20. The grout sleeve 20 is composed of plastic or a similar impermeable substance. In some forms in use a is Teflon TM or similar washer may be positioned between the skirt cup 24 and the dome shaped leading end 10. The washer acts as a grout seal while also lowering friction to reduce the chance of the skirt cup 24 and sleeve 20 rotating during tightening of the rock bolt shaft 2. 20 As best depicted in Figs 5 and 6, the grout sleeve 20 includes a continuous external spiral profile which promotes smooth grout flow both between the rock bolt shaft 2 and the sleeve 20, and external to the sleeve 20. 25 The continuous profile is in the form of a continuous spiral rope thread profile. The grout therefore flows within the sleeve 20 and between the sleeve 20 and bore hole wall. The continuous spiral profile reduces the occurrence of air pockets in the grout. Further the 30 profile allows a small annulus region between the sleeve 20 and the shaft 2 while keeping the inner and outer grout path separated. 3416212_1 (GHMatters) P90463.AU 19/06/12 - 11 The large amplitude of the rope thread profile achieves interlock between the rock wall shaft 2 and the bore hole wall through the sleeve 20. In the illustrated form the profile has an amplitude of 6 mm. In some forms the 5 amplitude may be between 4 mm and 8 mm. In the illustrated form the profile has a pitch of 22 mm. In some forms the pitch may be between 20 and 25 mm. The large amplitude allows for improved bond strength between the rock bolt shaft and the bore hole wall. 10 As best shown in Fig. 7 the sleeve 20 is positioned in use about the rock bolt shaft 2 such that an annular cavity 27 is defined between the sleeve 20 and the rock bolt shaft 2. In the illustrated form the sleeve 20 extends for the 15 whole length of the rock bolt shaft 2, providing a barrier to ground water or other fluids along the length of the rock bolt shaft. The skirt 24 is attached with the sleeve 20 and extends over the nut 7. In this form the channels 19 extending through the nut are in fluid communication 20 with the annular cavity 27 through the interior of the skirt 24 such that fluid or grout directed through the channels 19 proceeds into the skirt 24 and then into the annular cavity 27 to flow around the rock bolt shaft. The grout fills the bore hole from the bottom creating two 25 grout flow pathways, one external to the sleeve 20 and one internal to the sleeve 20 within the cavity 27 between the sleeve 20 and shaft 2. In use, the rock bolt 1 is inserted into a bore in a rock 30 substrate. The rock bolt sleeve is positioned about the rock bolt shaft 2. The nut 7 is positioned on the shaft 2. Grout is pumped into channels 19 such that the grout flows to the distal end 4 of the rock bolt shaft 2 and 3416212_1 (GHMatters) P90463.AU 19106112 - 12 fills the rock bore hole from the distal end to the proximal end. The grout fills the interior and exterior of the sleeve 20. s Upon the grout setting and forming a bond between the rock bolt shaft 2, the sleeve 20 and the bore hole wall, tension is placed on the rock bolt shaft 2 by rotating the nut to bear against the plate 8. 10 In some illustrated forms a tightening spanner 25 having a profiled tightened end 26 is configured to engage with the profiled end 17 of the nut 7 such that rotation of the tightening spanner results in rotation of the nut to bear further against the plate and therefore against the rock i5 substrate. As will be understood, variations of the above described rock bolt assembly can be made without departing from the scope of the appended claims. 20 While the rock bolt has been described in reference to its preferred embodiments, it is to be understood that the words which have been used are words of description rather than limitation and that changes may be made without 25 departing from its scope as defined by the appended claims. It is to be understood that a reference herein to a prior art document does not constitute an admission that the 30 document forms part of the common general knowledge in the art in Australia or in any other country. In the claims which follow and in the preceding 3416212_1 (GHMatters) P90463.AU 19/06/12 - 13 description, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to 5 specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the rock bolt. 3416212_1 (GHMatters) P90463.AU 19/06/12

Claims (26)

1. A rock bolt assembly having an elongate shaft configured to be at least partially located in a bore 5 formed in a rock substrate and a nut having an internal cavity extending therethrough, the internal cavity having a threaded internal surface, the nut including at least one channel configured for introducing grout to the assembly, the channel being located intermediate the 10 threaded internal surface and an external surface of the nut.

2. A rock bolt assembly as defined in claim 1, wherein the nut extends from a leading end to a trailing 15 end and the trailing end includes a planar surface, the channels being positioned such that they extend from the planar surface.

3. A rock bolt assembly as defined in claim 1 or 2 20 wherein the external surface comprises a dome.

4. A rock bolt assembly as defined in claim 3 when dependent upon claim 2, wherein the dome surrounds the planar surface. 25

5. A rock bolt assembly as defined in any of the preceding claims, wherein the or each channel extends adjacent the internal cavity. 30

6. A rock bolt as defined in any of the preceding claims, wherein the or each channel is configured such that it extends substantially parallel to the internal cavity. 3416212_1 (GHMatters) P90463.AU 19/o6/12 - 15

7. A rock bolt as defined in any of the preceding claims, wherein the or each channel comprises a plurality of channels spaced apart about the internal cavity. 5

8. A nut for a rock bolt assembly having an elongate shaft configured to be at least partially located in a bore formed in a rock substrate, the nut having: an internal cavity extending therethrough, the 10 internal cavity having a threaded internal surface, at least one channel configured for introducing grout to the rock bolt assembly, the channel being located intermediate the threaded internal surface and an external surface of the nut. 15

9. A nut as defined in claim 8, wherein the nut extends from a leading end to a trailing end and the trailing end includes a planar surface, the channels being positioned such that they extend from the planar surface. 20

10. A nut as defined in claim 8 or 9 wherein the external surface comprises a dome.

11. A nut as defined in claim 10 when dependent upon 25 claim 9, wherein the dome surrounds the planar surface.

12. A nut as defined in any one of claims 8 to 11, wherein the or each channel extends adjacent the internal cavity. 30

13. A nut as defined in any one of claims 8 to 12, wherein the or each channel extends such that it is substantially parallel to the internal cavity. 3416212_1 (GHMatters) P90463.AU 1906/12 - 16

14. A nut as defined in any one of claims 8 to 13, wherein the or each channel comprises a plurality of channels spaced apart about the internal cavity. 5

15. A sleeve for a rock bolt assembly having a rock bolt shaft, the sleeve being configured to be positioned about the rock bolt assembly and comprising an elongate tubular member having an external profile in the form of a 10 continuous protrusion.

16. A sleeve as defined in claim 15, wherein the continuous protrusion is helical. 15

17. A sleeve as defined in claim 15 or 16, wherein the protrusion is in the form of a helical ridge.

18. A sleeve as defined in claim 17, wherein the helical ridge has an amplitude of between 4 mm and 8 mm. 20

19. A sleeve as defined in any one of claims 15 to 18 having a skirt threadedly connected with the tubular member. 25

20. A rock bolt assembly comprising a rock bolt shaft configured to be at least partially located in a bore formed in a rock substrate, and a sleeve configured to be located in use about the rock bolt shaft, the sleeve including an external profile in the form of a continuous 30 helical protrusion, the shaft and sleeve defining an intermediate cavity therebetween.

21. A rock bolt assembly as defined in claim 20, wherein the intermediate cavity is annular. 3416212_1 (GHMatters) P90463.AU 19/06/12 - 17

22. A rock bolt assembly as defined in claim 20 or 21, further comprising a nut, having an internal nut cavity extending therethrough and at least one channel configured 5 for introducing grout to the rock bolt assembly, the channel being located intermediate the threaded internal surface and an external surface of the nut, the channel and the intermediate cavity being in fluid communication with one another. 10

23. A rock bolt assembly as defined in claim 22, further comprising a skirt extending from the sleeve and configured to be positioned in use over a portion of the nut such that the channel feeds into the skirt. 15

24. A rock bolt assembly as herein described with reference to the accompanying drawings.

25. A nut for a rock bolt assembly as herein described with reference to the accompanying drawings. 20

26. A sleeve for a rock bolt as herein described with reference to the accompanying drawings. 3416212_1 (GHMatters) P90463.AU 19/o612