Single Pass Drilling Apparatus, Use of a One-Piece Drill Bit, Method and Rock Bolt for Single Pass Rock Bolting

Abstract

The present invention relates to a single pass drilling apparatus, a rock bolt, use of a drill bit and a method for single pass rock bolting for reinforcement and stabilization of excavations. The single pass drilling apparatus comprises an elongated drill steel ( 11 ) having a leading ( 12 ) and a trailing end ( 1 3 ) with reference to a drilling direction (F). The leading end ( 12 ) has a connection portion. A one-piece drill bit ( 16 ) is utilized having rock machining means ( 17,18;17′18′ ). The drill bit is connectable to the drill steel. The single pass drilling apparatus ( 10 ) further comprises a rock bolt ( 21;121,221;321 ) adapted to at least partially enclose the drill steel ( 11 ). The greatest diametrical dimension (DB) of the drill bit ( 16 ) is smaller than the smallest diametrical dimension (DI) of the rock bolt.

1 . A single pass drilling apparatus comprising: 
 an elongated drill steel having a leading and a trailing end with reference to a drilling direction, said leading end having a connection portion, a one-piece drill bit having rock machining means, said drill bit being rigidly connected to the drill steel,    wherein the single pass drilling apparatus further comprises a rock bolt adapted to at least partially enclose the drill steel and in that the drill bit and the rock bolt are designed to allow the drill bit to pass the rock bolt during retraction of the drill bit.    
   
   
       2 . The single pass drilling apparatus according to  claim 1 , wherein the greatest diametrical dimension of the drill bit is smaller than the smallest diametrical dimension of the rock bolt and in that the one-piece drill bit comprises a pilot part and a reamer part having spaced middle lines.  
   
   
       3 . The single pass drilling apparatus according to  claim 2 , characterized in that the middle line of the pilot part substantially coincides with the center axis of the rock bolt during drilling.  
   
   
       4 . The single pass drilling apparatus according to  claim 2 , characterized in that the middle line of the reamer part substantially coincides with the rotational axis of the leading end of the drill steel.  
   
   
       5 . Use of a one-piece drill bit that comprises a pilot part and a reamer part having spaced middle lines in a single pass drilling apparatus according to  claim 1 .  
   
   
       6 . Method of single pass rock bolting comprising the following steps: 
 providing a single pass drilling apparatus comprising:    an elongated drill steel having a leading and a trailing end with reference to a drilling direction, said leading end having a connection portion,    a one-piece drill bit having rock machining means, said drill bit being rigidly connected to the drill steel,    enclosing the drill steel at least partially with a rock bolt, said drill bit and said rock bolt being designed to allow the drill bit to pass the rock bolt during retraction of the drill bit,    drilling a hole in a rock while pushing the rock bolt into said hole,    retracting said drill steel and said drill bit through the rock bolt.    
   
   
       7 . The method according to  claim 6 , wherein the method comprises the further step of providing the drill bit as a one-piece drill bit comprising a pilot part and a reamer part having spaced middle lines.  
   
   
       8 . A rock bolt for a single pass drilling apparatus as defined in  claim 1 , said rock bolt having a partly tube shaped body having a leading end and a trailing end, said trailing end having a washer and a washer stop means, said rock bolt being fluid expansible, 
 wherein the rock bolt is substantially semi-circular and designed as a general U-shape to allow passage of a drill bit rigidly connected to a drill steel.    
   
   
       9 . The rock bolt according to  claim 8 , wherein ends in a radial cross-section of the rock bolt are substantially diametrically opposite to each other.