Abstract: A method, performed by a centrifuge, for treating toughness and hardness of drill bit buttons is provided. The centrifuge comprises a chamber formed by a stationary side wall and a bottom which is rotatable around a rotation axis, the bottom comprising one or more protrusions which at least partly extends between the rotation axis and the side wall, the side wall comprising at least six pushing elements arranged around a periphery of the side wall. The method comprises rotating, by rotation of the bottom with the protrusions, the drill bit buttons around the rotation axis, pushing, by the pushing elements, the drill bit buttons from the side wall during the rotation of the bottom, collectively forming the drill bit buttons into a torus shape at the bottom of the chamber for inducing collisions between the drill bit buttons, thereby treating the toughness and hardness of the drill bit.

Abstract: A cutting tool is provided. The cutting tool comprises a tip, a body and a shank. The tip has a tip radius and a tip length. The body has a body radius and a body length between the shank and a recess portion along a longitudinal axis of the body. The recess portion comprises a wall which forms a recess with a depth into the body for retaining a major part of the tip length within the recess. The body radius at half the depth of the recess does not exceed two tip radiuses. The tip is made of a hard metal alloy with a hardness of at least 1300 HV50 and the body is made of a steel alloy with a hardness of at least 450 HV30.

Abstract: A device in a drill string component for percussive rock drilling including a thread for threading together with another drill string component including a complementary thread. The thread includes a thread groove formed by two thread flanks and an intermediate thread bottom. In operation one of the flanks forms a pressure flank. The thread groove has an essentially equally shaped sectional form along its axial extension. The thread bottom exhibits at least three surface portions with part-circular shape, as seen in an axial section. The surface portions with part-circular shape have increasing radiuses, as seen from each thread flank to an intermediate surface portion of the thread bottom. Also a thread joint and a drill string component.

Abstract: A hard metal insert for a drill bit for percussion drilling. A wear part includes a cap including a wear surface. A mount includes a cylindrical part having a cross-sectional area and a diameter. The cap includes a front part with an extension along an axis of symmetry of the insert from a first point on the wear surface to a second point in the cap. The front part includes a volume between a first plane intersecting the axis at the first point and a second plane intersecting the axis at the second point. The volume is ?0.6 times a cross-sectional area of the front part in the second plane times a distance along the axis between the first and second points. A diameter of the front part in the second plane is ?0.5 times the mount diameter and ?0.6 times the mount diameter.

Abstract: Drill bit (10) for a rock drilling tool (12), and a method of increasing the toughness of the drill bit, which drill bit (10) has a drilling surface (10b) that contacts rock during drilling. A longitudinal cross section (10t) of the drill bit (10) through the drilling surface (10b) exhibits certain relationships of Ltot(depth)/Ltot(5.0) and H(depth)/H(5.0) at the specified depths, along the drill bit's longitudinal axial center line (C) if the drill bit has a length (L) of 10 mm or greater, and Ltot(depth)/Ltot(3.5) and H(depth)/H(3.5) at the specified depths, if the drill bit has a length (L) of 10 mm or less.

Abstract: Rock drilling equipment and drill string components (2;18) for top hammer drilling and down-the-hole drilling for positioning between a drill rig and a drill bit include a pipe-shaped element (3;19), which is arranged for transferring only rotational movements from the drill rig to the drill hit. A vibration-damping structure (12) is arranged adjoining to at least a part of an inside (11) of the pipe-shaped element in a space (41) formed inwardly of the inside (11).

Abstract: Drill bit (10) for a rock drilling tool (12), which drill bit (10) has a drilling surface (10b) that contacts rock during drilling. A longitudinal cross section (10t) of the drill bit (10) through the drilling surface (10b) exhibits the following relationships of Ltot(depth)/Ltot(5.0) and H(depth)/H(5.0) at the specied depths, where H(depth)/H(5.0) is measured according to a Vickers test and Ltot(depth)/Ltot(5.0) is measured according to the Palmqvist method, described in this document substantially along the drill bit's longitudinal axial center line (C): (table (I)). If the drill bit (10) has en length (L) of 10 mm or greater, and a longitudinal cross section (10t) of the drill bit (10) through the drilling surface (10b) exhibits the following relationships of Ltot(depth)/Ltot(3.5) and H(depth)/H(3.5) at the specified depths, where H(depth)/H(3.5) is measured according to a Vickers test and Ltot(depth)/Ltot(3.

Abstract: A device in a drill string component for percussive rock drilling including a thread for threading together with another drill string component including a complementary thread. The thread includes a thread groove formed by two thread flanks and an intermediate thread bottom. In operation one of the flanks forms a pressure flank. The thread groove has an essentially equally shaped sectional form along its axial extension. The thread bottom exhibits at least three surface portions with part-circular shape, as seen in an axial section. The surface portions with part-circular shape have increasing radiuses, as seen from each thread flank to an intermediate surface portion of the thread bottom. Also a thread joint and a drill string component.

Abstract: A hard metal insert for a drill bit for percussion drilling. A wear part includes a cap including a wear surface. A mount includes a cylindrical part having a cross-sectional area and a diameter. The cap includes a front part with an extension along an axis of symmetry of the insert from a first point on the wear surface to a second point in the cap. The front part includes a volume between a first plane intersecting the axis at the first point and a second plane intersecting the axis at the second point. The volume is ?0.6 times a cross-sectional area of the front part in the second plane times a distance along the axis between the first and second points. A diameter of the front part in the second plane is ?0.5 times the mount diameter and ?0.6 times the mount diameter.

Abstract: In percussion rock drilling a screw joint for a drill run or drill string including male and female screw threads (5, 9) on the elements (1, 2) are joined together to form a drill string. Within the screw joint the male thread (5) and the female thread (9) have a trapezoidal shape and a slight conical inclination.

Abstract: Pressure-air driven percussion device for a down-the-hole drill with a hammer-piston which is axially reciprocally movable in a hammer-piston chamber through a driving device. The hammer-piston in operation acting with a hammer-end against an upper end of a drill bit which is positioned inside a chuck. An air-cushion for reducing percussive power is arranged to be formed at the hammer-end of the hammer-piston in positions where the drill bit has been moved past a predetermined distance in the percussion direction. The drill bit is sealingly slidingly supported in a drill bit bushing, and the hammer-end of the hammer-piston is formed so that it sealingly cooperates with the drill bit bushing in the positions in order to form the air-cushion.

Abstract: A fluid channeling device (10) is for a down-hole drill assembly (1) having a central axis (1c) and advanceable into a hole in a downward direction (D) along the axis (1c). The assembly (1) includes a drill member (2) with an inner surface (2a) bounding a central bore (2b) and an outer surface (2c). The channeling system includes at least one passage (12) provided within the drill member (2) so as to extend generally between the drill member inner (2a) and outer surfaces (2c). A generally annular channeling member (14) is disposeable about a portion of the drill member (2) and has at least one inlet port (20), at least one discharge port (16), and a passage (12) extending between the inlet (20) and discharge ports (16). The inlet port (20) is fluidly connectable with the drill member passage (12) to fluidly couple the central bore (2b) with the discharge port (16).

Abstract: A drill bit assembly for direct removal of rock with a rotatable bit assembly (5) that includes a plurality of cutters or choppers (7). According to the invention, an number of cutters (7) are so disposed in relation to each other or the bit assembly (5) that a subsequent cutter (7b), seen in the direction of rotation, will engage an edge created by the action of preceding cutter (7a).

Abstract: A bit assembly is for a drill having a casing, a central axis and a hammer movably disposed within the casing. The bit assembly includes a chuck with a tubular body having first and second ends, the first end being connected with the casing such that the second end is spaced axially therefrom, and one or more openings extending generally axially from the second end toward the first end. A bit includes a body with a tubular portion having a cavity and one or more axial lugs, the lug(s) being disposable within the chuck opening(s). A retainer is coupled with the chuck, disposable within the bit cavity and engageable with the bit lug(s) so as to releasably couple the bit with the chuck. The retainer is preferably a deflectable ring sized to receive a portion of the hammer, such that the hammer prevents disengagement of the retainer from the bit.

Abstract: An arrangement for replenishing lubricating grease in drill cutters (3) that include a conical outer barrel (7) which is rotatable about a shaft (5) disposed centrally in the cutter, wherein there is provided in the cutter shaft (5) a passageway (16) that extends along the shaft from the cutter end of largest diameter and that connects with a transverse passageway (18) which opens into a bearing-accommodating space (13) in the cutter for delivering lubricating grease to the space (13), and wherein a lubricating nipple (19) is provided on the cutter end wall of largest diameter and functions to allow lubricating grease to be released from the bearing-accommodating space (13).

Abstract: A device is for channeling solids and fluids within a reverse circulating, fluid operated drill that has first and second ends, an axis extending between the ends, a casing and a piston. The casing has a bore extending between the drill ends and drive and valve chambers defined within the bore, the piston being movably disposed within the bore. The channeling device includes an elongated body disposeable within the casing bore so as to extend along the casing axis and through the piston. The body has a longitudinal axis, a first end locatable proximal to the drill first end, and a second end spaced from the first end and locatable proximal to the drill second end. A material transport passages extends axially between the two body ends and provides a path for moving solid materials through the drill. A fluid passage is configured to couple the valve and drive chambers.

Abstract: A fluid distributor device is for a percussive drill assembly including a generally tubular casing (2) having a longitudinal centerline and a piston (6) disposed within the casing so as to define a reservoir chamber (27) in the casing. The distributor device comprises a generally cylindrical body (12) disposed within the casing and including a central axis, two opposing ends spaced apart along the axis, first and second interior chambers and a port fluidly connecting the two chambers. The body further has a plurality of fluid passages extending between the two ends and fluidly connecting the first chamber with the reservoir chamber and a deflectable retainer portion (16) releasably engaged with the casing so as to retain the body at a desired position with respect to the casing centerline. A valve (7) is disposed within the body and is configured to permit fluid flow through the port and to alternatively prevent fluid flow through the port.

Abstract: A connection rod (1) for rock drilling includes a first rod part (2) whidh has an external thread (4) provided at one end thereof, wherein the end of the rod opposite to the one end includes an end portion (6) which carries an internal thread (5), wherein the end portion (6) is joind to the first rod part (2) by friction welding and wherein the end portion (6) has been heat treated prior to being joined to the first rod part (2). The invention also relates to a method of producing such a connection rod.