Rock bolt

Abstract

A rock bolt ( 1 ) has a tubular body ( 2 ) with first and second ends ( 3, 4 ). The first end ( 3 ) is substantially sealed. A threaded rod ( 5 ) extends from the tubular body second end ( 4 ) for receiving a nut 102. A portion ( 6 ) of the tubular body ( 2 ) at the second end ( 4 ) is crimped on to the threaded rod ( 5 ). A rock bolt assembly is also disclosed comprising a rock bolt ( 1 ), a sleeve ( 105 ) coaxially mounted oil the rock bolt ( 1 ), a resin cartridge ( 104 ) received in the sleeve ( 105 ) and a collar ( 107 ) mounted on the leading end ( 106 ) of the sleeve ( 105 ) to engage a rock face and prevent the sleeve ( 105 ) from entering a hole in the rock face into which the rock bolt ( 1 ) is installed.

The claims defining the invention are as follows:  
     
         1 . A rock bolt comprising: 
 a tubular body having first and second ends, said tubular body first end being substantially sealed; and    a threaded rod extending from said tubular body second end for receiving a nut;    wherein a portion of said tubular body at said second end is crimped onto said threaded rod.    
     
     
         2 . The rock bolt of  claim 1  wherein said crimped portion of said tubular body has a length of at least 100 mm.  
     
     
         3 . The rock bolt of either of claims  1  and  2  wherein said threaded rod extends into said tubular body beyond said crimped portion.  
     
     
         4 . The rock bolt of any one of  claims 1  to  3  wherein said threaded rod is provided with an enlarged head, said enlarged head being disposed within said tubular body.  
     
     
         5 . The rock bolt of  claim 4 , when appended to  claim 3 , wherein said enlarged head is located a distance from a shoulder defined by the junction between said crimped portion of said tubular body and an adjacent uncrimped portion thereof.  
     
     
         6 . The rock bolt of either of claims  3  and  5  wherein said crimped portion of said tubular body is configured such that said threaded rod is displaced relative to said crimped portion upon application of a predetermined tensile load less than the ultimate tensile strength of said tubular body and of said threaded rod.  
     
     
         7 . The rock bolt of  claim 6  wherein said predetermined tensile load is in excess of 90% of the lesser of said tubular body ultimate tensile strength and said threaded rod ultimate tensile strength.  
     
     
         8 . The rock bolt of anyone of  claims 1  to  7  wherein said tubular body first end is crimped.  
     
     
         9 . The rock bolt of anyone of  claims 1  to  8  wherein said exterior surface of said tubular body is provided with generally helical deformations.  
     
     
         10 . The rock bolt of anyone of  claims 1  to  9  wherein a second threaded rod extends from said tubular body first end for receiving an expansion shell.  
     
     
         11 . A rock bolt assembly comprising: 
 a rock bolt having first and second ends, said rock bolt having a threaded portion at said second end;    a sleeve having leading and trailing ends and being coaxially mounted on said rock bolt with said leading end extending beyond said rock bolt first end to define a cavity;    a resin cartridge received in said cavity; and    a first detent means associated with said sleeve leading end adapted to engage a rock face about a hole in which said rock bolt is to be installed to thereby prevent said sleeve from entering said hole.    
     
     
         12 . The rock bolt assembly of  claim 11  wherein said first detent means is in the form of a first collar coaxially mounted on said resin cartridge adjacent said sleeve leading end, said collar having a leading face adapted to engage said rock surface and a trailing face adapted to engage said sleeve leading end.  
     
     
         13 . The rock bolt assembly of either of claims  11  and  12  wherein said sleeve is readily destructible.  
     
     
         14 . The rock bolt assembly of  claim 13  further comprising a second detent means adapted to engage said sleeve trailing end on installation of said rock bolt into said hole and compress and/or tear said sleeve between said first and second detent means;  
     
     
         15 . The rock bolt assembly of  claim 14  wherein said second detent means is in the form of a second collar coaxially mounted on said bolt towards said second end thereof, said second collar having a leading face adapted to engage said sleeve trailing end and a trailing face adapted to engage a nut threaded onto said rock bolt threaded portion.  
     
     
         16 . The rock bolt assembly of anyone of  claims 13  to  15  wherein said first collar trailing face is provided with an annular tapered surface adapted to tear said sleeve upon engagement therewith.  
     
     
         17 . The rock bolt assembly of  claim 15  wherein said second collar, leading face is provided with an annular tapered surface adapted to tear said sleeve upon engagement therewith.  
     
     
         18 . The rock bolt assembly of any one of  claims 11  to  17  wherein said sleeve is formed of cardboard material.  
     
     
         19 . A rock bolt substantially as hereinbefore described with reference to any one of FIGS.  1  to  3  or  5 .  
     
     
         20 . A rock bolt assembly substantially as hereinbefore described with reference to FIG. 4.