Top hammer rock-drilling tool, a drill rod coupling sleeve

Abstract

In a first aspect, the invention relates to a rock-drilling tool that comprises a drill rod ( 1 ) having a male thread ( 5 ) as well as a coupling sleeve having a female thread for the co-operation with the male thread of the drill rod. The male thread ( 5 ) of the drill rod may consist of a martensitic stainless steel. Axially inside the male thread ( 5 ), a waist ( 32 ) is formed in which the drill rod ( 1 ) has the smallest diameter thereof. Furthermore, an external, cylindrical guide surface ( 31 ) is positioned between the male thread ( 5 ) and the waist ( 32 ) and has the purpose of co-operating with an internal guide surface positioned between the female thread and a free end of the coupling sleeve. Furthermore, the invention relates to a drill rod as such as well as a coupling sleeve as such.

1 . A top hammer rock-drilling tool comprising a drill rod having a male thread, and a coupling sleeve having a female thread for the co-operation with the male thread of the drill rod, wherein the male thread of the drill rod may consist of a martensitic, stainless steel, and that a waist is formed axially inside the male thread, in which waist the drill rod has the smallest diameter thereof, an external, cylindrical guide surface being positioned between the male thread and the waist and having the purpose of co-operating with an internal guide surface positioned between the female thread and a free end of the coupling sleeve. 
   
   
       2 . Rock-drilling tool according to  claim 1 , wherein between the guide surface and male thread of the drill rod, an envelope surface is formed, the diameter of which is smaller than the diameter of the guide surface, and in which the groove of the male thread runs out. 
   
   
       3 . Rock-drilling tool according to  claim 1 , wherein the waist of the drill rod transforms into the guide surface as well as into a cross section-wise hexagonal section or round section of the drill rod, via concavely arched, successively expanding transition surfaces. 
   
   
       4 . Rock-drilling tool according to  claim 1 , wherein the axial distance between the guide surface of the drill rod and the end surface thereof is only somewhat smaller than the distance between the free end of the coupling sleeve and an internal partition wall against which the free end of the drill rod is pressable. 
   
   
       5 . Rock-drilling tool according to  claim 1 , wherein the guide surface of the drill rod has a diameter that is at least twice as large as the axial extension thereof, and wherein the male thread has a wear volume that is larger than the wear volume of the female thread. 
   
   
       6 . A top hammer drill rod for rock-drilling tools, comprising a male thread that is formed adjacent to a free end and in the form of a helix thread ridge having a crest and two flanks, which delimit a likewise helix groove having a bottom, wherein said male thread may consist of a martensitic, stainless steel, and that axially inside the male thread, a waist is formed in which the drill rod has the smallest diameter thereof, a cylindrical guide surface being formed between the waist and the male thread, the diameter of which guide surface is larger than the outer diameter of the thread ridge. 
   
   
       7 . Drill rod according to  claim 6 , wherein an envelope surface is formed between the guide surface and the male thread, the diameter of which envelope surface is smaller than the diameter of the guide surface and in which the groove of the male thread runs out. 
   
   
       8 . Drill rod according to  claim 6 , wherein the waist thereof transforms into the guide surface as well as into a cross-section-wise hexagonal section or round section via concavely arched, successively expanding transition surfaces, and wherein the cross-sectional area of the thread ridge is larger than the imaginary cross-sectional area of the groove. 
   
   
       9 . A coupling sleeve for top hammer rock-drilling tools, the coupling sleeve comprising two hollow spaces, which terminate in opposite directions and are separated by a partition wall, and in which female threads are formed, wherein a first female thread is spaced-apart from a free end of an internal, cylindrical guide surface, the first female thread being a thread ridge having a crest and two flanks that delimit a helix groove having a bottom, the width of the thread ridge being smaller than the width of the groove. 
   
   
       10 . Coupling sleeve according to  claim 9 , that wherein the partition wall has an axial thickness, and wherein the guide surface has an axial length, said length being greater than said thickness. 
   
   
       11 . Rock-drilling tool according to  claim 2 , wherein the waist of the drill rod transforms into the guide surface as well as into a cross section-wise hexagonal section or round section of the drill rod, via concavely arched, successively expanding transition surfaces. 
   
   
       12 . Drill rod according to  claim 7 , wherein the waist thereof transforms into the guide surface as well as into a cross-section-wise hexagonal section or round section via concavely arched, successively expanding transition surfaces, and wherein the cross-sectional area of the thread ridge is larger than the imaginary cross-sectional area of the groove.