A drill bit (11) for the drilling, in particular the rotary percussive drilling, of a hole, in particular a tap hole of a melting furnace, the drill bit (11) comprising a drill head (10), which has at least one hard material insert (16), and a base body (12) for connecting the drill bit to a driving element, the hard material insert (16) being inserted into a seat, which is formed in an axial end face (13) of the drill head (10), in such a manner that at least a head cutting edge (18) of the hard material insert (16) protrudes beyond the axial end face (13), wherein the seat has a flank portion and a mating flank portion located opposite the flank portion, between which the hard material insert (16) is disposed, the flank portion, which is disposed opposite a recess formed in the hard material insert (16), being provided with a material projection (35) which is at least partially made of a welding material, is bonded to the drill head (10) via the welding material and protrudes into the recess so as to establish a form-fitting connection with the hard material insert (16).

This disclosure relates to a percussive drill bit comprising PCD studs and a hard facing material that is strategically located to minimise stud pop outs and the amount of hard facing material used.

This disclosure relates to a percussive drill bit comprising PCD studs and a hard facing material that is strategically located to minimise stud pop outs and the amount of hard facing material used.

A down the hole rock drilling machine and a method of drilling rock. The drilling machine comprises a casing (15) inside which is a control sleeve (20). A reciprocating piston (19) is arranged to move inside the control sleeve and control feeding and discharging of working chambers (20, 21). Between the control sleeve and an inner surface of the casing are all the fluid passages (28, 29, 30, 31) needed for fluid routing. The piston opens and closes transverse openings and controls the work cycle.

A down the hole rock drilling machine and a method of drilling rock. The drilling machine comprises a casing (15) inside which is a control sleeve (20). A reciprocating piston (19) is arranged to move inside the control sleeve and control feeding and discharging of working chambers (20, 21). Between the control sleeve and an inner surface of the casing are all the fluid passages (28, 29, 30, 31) needed for fluid routing. The piston opens and closes transverse openings and controls the work cycle.

A pressurized fluid flow system for a down the hole drill hammer has main and auxiliary chambers that exert work on the piston. The auxiliary chambers are formed around respective waists on the piston and externally delimited by respective cylinders which are arranged longitudinally in series. A set of supply chambers filled with the pressurized fluid are defined by annular recesses in the external surface of the piston for supplying said fluid to the chambers. Supply channels and discharge channels are formed in between the outer casing and the cylinders for respectively supply pressurized fluid through exit ports in the cylinders to the supply chambers and emptying the chambers through discharge ports in the cylinders. The supply and discharge of the chambers is controlled in a cooperative way by the piston and the cylinders. A normal circulation drill hammers is provided having this system.

A pressurized fluid flow system for a down the hole drill hammer has main and auxiliary chambers that exert work on the piston. The auxiliary chambers are formed around respective waists on the piston and externally delimited by respective cylinders which are arranged longitudinally in series. A set of supply chambers filled with the pressurized fluid are defined by annular recesses in the external surface of the piston for supplying said fluid to the chambers. Supply channels and discharge channels are formed in between the outer casing and the cylinders for respectively supply pressurized fluid through exit ports in the cylinders to the supply chambers and emptying the chambers through discharge ports in the cylinders. The supply and discharge of the chambers is controlled in a cooperative way by the piston and the cylinders. A normal circulation drill hammers is provided having this system.

A flushing system in a drill bit, which has a body that defines the flushing system, can include an inlet to facilitate supply of pressurized fluids into a bore hole. A cutting surface of the drill bit is provided with a main opening that defines a main passageway in communication with the inlet. A peripheral surface of the drill bit is provided with a secondary opening that defines a secondary passageway in communication with the inlet. The secondary passageway is disposed at an angle from a horizontal reference plane. The horizontal reference plane is defined between the inlet and the origin of the main passageway and is perpendicular to a central longitudinal axis of the body of the drill bit. An origin of the secondary passageway is at a distance from the origin of the main passageway.

A flushing system in a drill bit, which has a body that defines the flushing system, can include an inlet to facilitate supply of pressurized fluids into a bore hole. A cutting surface of the drill bit is provided with a main opening that defines a main passageway in communication with the inlet. A peripheral surface of the drill bit is provided with a secondary opening that defines a secondary passageway in communication with the inlet. The secondary passageway is disposed at an angle from a horizontal reference plane. The horizontal reference plane is defined between the inlet and the origin of the main passageway and is perpendicular to a central longitudinal axis of the body of the drill bit. An origin of the secondary passageway is at a distance from the origin of the main passageway.

A down-the-hole drilling assembly activated by fluid under pressure includes a casing having an axially rearward and forward end, a piston arranged movably inside the casing, a plurality of fluid passages for feeding and discharging pressurized fluid into and out of a working chamber for generating reciprocating movement of the piston, a drill bit at the forward end and provided with an anvil facing towards the piston for receiving impacts therefrom and an annular drive sub surrounding at least a portion of a shank and cooperating with the bit to form fluid passages extending length-wise along the shank. The drive sub has a concave arcuate groove extending circumferentially to form a chamber for collecting fluid from the hammer exhaust and redistributing a volume of the collected fluid from channels formed between complimentary splines of the drive sub and splines of the bit to flushing holes arranged in the bit.