Down-the-hole drill hammer

Abstract

The present invention relates to an arrangement pertaining to down-the-hole hammers in which a driver ( 7 ) is adapted to transfer torsion forces between a rotating outer tube ( 10 ) and a drill bit ( 1 ) of the hammer, wherein the outer tube ( 10 ) surrounds all of the driver ( 7 ).

1 . An arrangement pertaining to down-the-hole hammers in which a driver ( 7 ) is adapted to transfer torsion forces between a rotating outer tube ( 10 ) and a drill bit ( 1 ) of the hammer, characterised in that the outer tube ( 10 ) is made of steel and is arranged outwardly surrounding all of the driver ( 7 ), and that the driver is made of a softer material than that in the outer tube ( 10 ).  
   
   
       2 . An arrangement according to  claim 1 , characterised in that the driver ( 7 ) is made of a bronze alloy.  
   
   
       3 . An arrangement according to  claim 2 , characterised in that the driver ( 7 ) is made of a copper alloy.  
   
   
       4 . An arrangement according to  claim 3 , characterised in that the outer tube ( 10 ) has an outer coating that consists of a material which is harder than the material from which said tube ( 10 ) is chiefly comprised.