Hartmetalleinsatz und Gesteinsbohrer

Abstract

The invention relates to a carbide insert ( 2 ) for a rock drill ( 1 ), which is configured as a non-percussively operating twist drill with a cylindrical drill body ( 11 ) and a working end ( 13 ) having the carbide insert ( 2 ), the carbide insert ( 2 ) having two cutting lips ( 22 ) which are radially opposite one another relative to an axis of drill rotation (d) and are arranged at an angle to one another to form a centering tip ( 21 ) and with each of which a peripheral conveyor spiral ( 14 ) may be associated. To be able to introduce a drilled hole more quickly, easily and simply and with less risk of damage into a workpiece of rock, rock-like material, hard plastics, glass or the like, it is proposed that the cutting lips ( 22 ) be configured asymmetrically to one another, wherein at least one of the cutting lips ( 22 ) defines over its radial profile, in a central region spaced from its radial ends, a tip ( 23 ) projecting in the drilling direction (b).

1 . A carbide insert ( 2 ) for a rock drill ( 1 ), which is configured as a non-percussively operating twist drill for drilling rock, rock-like material, hard plastics, glass or the like with a cylindrical drill body ( 11 ) and a working end ( 13 ) having the carbide insert ( 2 ), the carbide insert ( 2 ) comprising:
 two cutting lips ( 22 ) which are radially opposite one another relative to an axis of drill rotation (d) and are arranged at an angle to one another to form a centering tip ( 21 ) and with each of which a peripheral conveyor spiral ( 14 ) is associated, the cutting lips ( 22 ) being configured asymmetrically to one another, at least one of the cutting lips ( 22 ) defining over its radial profile, in a central region spaced from its radial ends, a tip ( 23 ) projecting in the drilling direction (b), the centering tip ( 21 ) being axially symmetrically tapered relative to the axis of drill rotation (d) and the carbide insert being of plate-shaped configuration,   a first flute-like recess ( 271 ) in a leading position relative to a cutting edge ( 25 ) of one of the cutting lips ( 22 ) in the direction of drill rotation (r) and extending into the associated conveyor spiral ( 14 ) is introduced (A 5 ) radially inwardly and/or a second flute-like recess ( 272 ) in a leading position relative to a cutting edge ( 25 ) of the other cutting lip ( 22 ) in the direction of drill rotation (r) and extending into the associated conveyor spiral ( 14 ) is introduced (A 5 ) radially outwardly into the drill body ( 11 ), and in that the two recesses ( 271 ,  272 ) each form a profile portion of the associated cutting lip ( 22 ) and adjoin one another radially, so forming a discontinuity in the radial profile of the cutting lip ( 22 ).   
     
     
         2 . The carbide insert ( 2 ) as claimed in  claim 1 , wherein the tip ( 23 ) of at least one cutting lip ( 22 ) is defined radially inwardly and radially outwardly by an uncurved or by a concavely curved free-running surface ( 24 ). 
     
     
         3 . The carbide insert ( 2 ) as claimed in  claim 1 , wherein the tip ( 23 ) divides the cutting lip ( 22 ) into a radially outer portion (a 1 ) and a radially inner portion (a 2 ), the ratio of the length of the outer portion (a 1 ) to that of the inner portion (a 2 ) is ≤1. 
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . (canceled) 
     
     
         7 . The carbide insert ( 2 ) as claimed in  claim 1 , wherein the discontinuity formed by the mutually adjoining recesses ( 271 ,  272 ) is arranged at a radial point (P) of one cutting lip ( 22 ) which is different from the free end point of the tip ( 23 ) of this cutting lip ( 22 ). 
     
     
         8 . The carbide insert ( 2 ) as claimed in  claim 7 , wherein the point (P) with the discontinuity of one cutting lip ( 22 ) formed by the mutually adjoining recesses ( 271 ,  272 ) is arranged radially inwardly relative to the tip ( 23 ) of this cutting lip ( 22 ). 
     
     
         9 . The carbide insert ( 2 ) as claimed  claim 8 , wherein the first recess ( 271 ) and/or second recess ( 272 ) are arranged in the drilling direction (b) angled towards the axis of drill rotation (d) at an angle to same. 
     
     
         10 . The carbide insert ( 2 ) as claimed in  claim 9 , wherein the two cutting lips ( 22 ) each have the tip ( 23 ) projecting in the drilling direction (b), wherein the tip ( 23 ) of the one cutting lip ( 22 ) is arranged at a first radius (r 1 ) which is different from a second radius (r 2 ) of the tip ( 23 ) of the other cutting lip ( 22 ). 
     
     
         11 . The carbide insert ( 2 ) as claimed in  claim 10 , wherein the tip ( 23 ) of one cutting lip ( 22 ) is arranged on the radially inner half of the cutting lip ( 22 ) and the tip ( 23 ) of the other cutting lip ( 22 ) is arranged on the radially outer half of the other cutting lip ( 22 ). 
     
     
         12 . The carbide insert ( 2 ) as claimed in  claim 11 , wherein the centering tip ( 21 ) has a centering angle (β) which amounts for drilling of glass to 50° to 70°, wall tiles to 70° to 80° or floor tiles, thermosets and hard composites to 110° to 140°. 
     
     
         13 . (canceled) 
     
     
         14 . A rock drill ( 1 ) configured as a non-percussively operating twist drill for drilling rock, rock-like material, hard plastics, glass or the like, wherein the rock drill ( 1 ) has a cylindrical drill body ( 11 ) and a working end ( 13 ) with a carbide insert ( 2 ) as claimed in  claim 1 . 
     
     
         15 . The rock drill ( 1 ) as claimed in  claim 14 , wherein the carbide insert ( 2 ), includes a first flute-like recess ( 271 ) in a leading position relative to the cutting edge ( 25 ) of the cutting lip ( 22 ) in the direction of drill rotation (r) and extending into the associated conveyor spiral ( 14 ) is introduced radially inwardly and/or a second flute-like recess ( 272 ) in a leading position relative to the cutting edge ( 25 ) of the cutting lip ( 22 ) in the direction of drill rotation (r) and extending into the associated conveyor spiral ( 14 ) is introduced radially outwardly into the drill body ( 11 ), wherein the recesses ( 271 ,  272 ) of the cutting lip ( 22 ) extend contrary to the drilling direction (b) to the conveyor spiral ( 14 ) associated with this cutting lip ( 22 ) or lead into the conveyor spiral ( 14 ) associated with this cutting lip ( 22 ). 
     
     
         16 . The rock drill ( 1 ) as claimed in  claim 15 , wherein the first recess ( 271 ) of the cutting lip ( 22 ) leads, contrary to the drilling direction (b), into the second recess ( 272 ) associated with this cutting lip ( 22 ) and the second recess in turn leads, contrary to the drilling direction (b), into the conveyor spiral ( 14 ) associated with this cutting lip ( 22 ). 
     
     
         17 . The carbide insert ( 2 ) as claimed  claim 1 , wherein the first recess ( 271 ) and/or second recess ( 272 ) are arranged in the drilling direction (b) angled towards the axis of drill rotation (d) at an angle to same. 
     
     
         18 . The carbide insert ( 2 ) as claimed in  claim 17 , wherein the two cutting lips ( 22 ) each have the tip ( 23 ) projecting in the drilling direction (b), the tip ( 23 ) of one cutting lip ( 22 ) is arranged at a first radius (r 1 ) which is different from a second radius (r 2 ) of the tip ( 23 ) of the other cutting lip ( 22 ). 
     
     
         19 . The carbide insert ( 2 ) as claimed in  claim 18 , wherein the tip ( 23 ) of one cutting lip ( 22 ) is arranged on the radially inner half of the cutting lip ( 22 ) and the tip ( 23 ) of the other cutting lip ( 22 ) is arranged on the radially outer half of the other cutting lip ( 22 ). 
     
     
         20 . The carbide insert ( 2 ) as claimed in  claim 19 , wherein the centering tip ( 21 ) has a centering angle (β) which amounts for drilling of glass to 50° to 70°, wall tiles to 70° to 80° or floor tiles, thermosets and hard composites to 110° to 140°. 
     
     
         21 . The carbide insert ( 2 ) as claimed in  claim 17 , wherein the two cutting lips ( 22 ) each have the tip ( 23 ) projecting in the drilling direction (b), the tip ( 23 ) of the one cutting lip ( 22 ) is arranged at a first radius (r 1 ) which is different from a second radius (r 2 ) of the tip ( 23 ) of the other cutting lip ( 22 ). 
     
     
         22 . The carbide insert ( 2 ) as claimed in  claim 1 , wherein the two cutting lips ( 22 ) each have the tip ( 23 ) projecting in the drilling direction (b), the tip ( 23 ) of the one cutting lip ( 22 ) is arranged at a first radius (r 1 ) which is different from a second radius (r 2 ) of the tip ( 23 ) of the other cutting lip ( 22 ). 
     
     
         23 . The carbide insert ( 2 ) as claimed in  claim 1 , wherein the tip ( 23 ) divides the cutting lip ( 22 ) into a radially outer portion (a 1 ) and a radially inner portion (a 2 ), wherein the ratio of the length of the outer portion (a 1 ) to that of the inner portion (a 2 ) is ≤½. 
     
     
         24 . The carbide insert ( 2 ) as claimed in  claim 1 , wherein the tip ( 23 ) divides the cutting lip ( 22 ) into a radially outer portion (a 1 ) and a radially inner portion (a 2 ), the ratio of the length of the outer portion (a 1 ) to that of the inner portion (a 2 ) is ≤⅓.