Rock Bolt

Abstract

A rock bolt is for use in stabilizing a rock face. The rock bolt comprises a body having a plurality of elongate lobes spaced apart by substantially resilient channel means. The rock bolt is further configured to receive expansion means for urging the lobes outwardly to thereby expand the rock bolt for improving a communication with a bore hole in the rock face. Following expansion the expansion means may be removable, the expansion means can comprise any suitably sized hollow or solid bar expansion member. The configuration of the present invention also enables, subsequent to an initial expansion, the resilient channel means to provide a gripping force on any suitably sized member inserted into the internal space. This feature of the rock bolt allows for a mesh plate having an elongate portion to be securely and removably fitted to the rock bolt after the rock bolt has been expanded.

1 . A rock bolt for use in stabilising a rock body, the rock bolt comprising a body having a first open end, a second open end and a length along a longitudinal axis, the body comprising a wall having an internal surface defining an internal space, wherein the wall comprises a plurality of elongate lobes spaced apart and connected together by channel means running, at least in part, along the length of the rock bolt. 
     
     
         2 . A rock bolt according to  claim 1 , wherein the channel means comprise wall sections connected together and configured to provide a substantially resilient inwardly disposed junction between adjacent lobes. 
     
     
         3 . A rock boll according to  claim 1 , wherein the rock bolt further comprises expansion means to be received into the internal space for urging the lobes into an outward expansion. 
     
     
         4 . A rock bolt according to  claim 2 , wherein the expansion means engages with a plurality of inwardly disposed junctions. 
     
     
         5 . A rock bolt according to  claim 1 , wherein the lobes are evenly spaced around the wall. 
     
     
         6 . A rock bolt according to  claim 1 , wherein the rock bolt comprises three lobes. 
     
     
         7 . A rock bolt according to  claim 1 , wherein the rock bolt comprises connection means for assisting in operation and handling of the rock bolt. 
     
     
         8 . A rock bolt according to  claim 1 , wherein the connection means comprises a collar disposed proximal the second end, the collar and the rock bolt joined together by a tall circumferential join. 
     
     
         9 . A rock bolt according to  claim 7 , wherein the rock bolt comprises a portion substantially free of channel means. 
     
     
         10 . A rock bolt according to  claim 9 , wherein the portion is disposed between the connection means and the second end. 
     
     
         11 . A rock bolt according to  claim 1 , wherein each lobe comprises a contact surface for abutting a bore hole surface. 
     
     
         12 . A rock bolt according to  claim 11 , wherein each contact surface comprises a portion having a greater curvature than the bore hole before insertion of the expansion means. 
     
     
         13 . A rock bolt according to  claim 3 , wherein the expansion means comprises an insertion member. 
     
     
         14 . A rock bolt according to  claim 13 , wherein the insertion member comprises a solid bar ha mg a cylindrical configuration. 
     
     
         15 . A rock bolt according to  claim 13 , wherein the insertion member comprises a hollow tube having a cylindrical configuration. 
     
     
         16 . A rock bolt according to  claim 13 , wherein the insertion member comprises a wedge piece. 
     
     
         17 . A rock bolt according to  claim 16 , wherein the contact surface is configured to be deformable upon insertion of the expansion means so as to improve a contact with the bore hole surface. 
     
     
         18 . A rock bolt according to  claim 17 , wherein the deformation has a plastic component, such that upon removal of the expansion means the contact surface remains in substantial contact with the bore hole surface. 
     
     
         19 . A rock bolt according to  claim 1 , wherein the rock bolt is configured to receive and restrain a mesh plate having a suitably sized elongate portion inserted into the internal space. 
     
     
         20 . A rock bolt according to  claim 19 , wherein the plurality of junctions engage and restrain the expansion means and/or the elongate portion.