A drill bit for percussive rock drilling tools includes a drill bit head having a front surface including a face surface defining a forward-most end of the drill bit head and at least one hole in the drill bit head for receiving a button. The drill bit includes at least one recess located in the face surface. The recess is larger than the hole. The hole is disposed in the recess so that an open end of the hole is disposed below the face surface. The drill bit head further includes a gauge surrounding the face surface, the recess being partially disposed in the gauge.

A drill bit for percussion drilling includes a drill bit body including a front surface. The front surface includes a first circular area arranged transverse and coaxially to the axis of the drill body, a second area surface surrounding the first area surface, and a third area surface surrounding the second area surface. A number of buttons are arranged in the second and third area surfaces. The button body of each button has a forward end surface. The buttons are arranged in circular recesses extending substantially transverse from the second surface and third area surface into the drill bit body. The recesses have a radius corresponding to the button body radius and a depth corresponding to the length of the button body, such that the button bodies are fitted within the drill bit body with the forward end surface exposed in the second and third area surfaces.

The present disclosure describes various embodiments, as well as features and aspects thereof, of an improved drill bit assembly for a percussion boring system. More specifically, one non-limiting embodiment of an improved drill bit assembly for a percussion boring system comprises a bit and a product engagement member. The bit comprises a slant faced head and at least one exhaust port. The product engagement member comprises a product coupling portion and at least one fluid restriction portion. This improved drill bit assembly is such that, when the product engagement member is detachably engaged with the slant faced head of the bit, a first portion of the fluid stream expelled from the bit is directed substantially forward of the slant faced head and a second portion of the fluid stream is directed substantially rearward from the slant faced head.

The present disclosure describes various embodiments, as well as features and aspects thereof, of an improved drill bit assembly for a percussion boring system. More specifically, one non-limiting embodiment of an improved drill bit assembly for a percussion boring system comprises a bit and a product engagement member. The bit comprises a slant faced head and at least one exhaust port. The product engagement member comprises a product coupling portion and at least one fluid restriction portion. This improved drill bit assembly is such that, when the product engagement member is detachably engaged with the slant faced head of the bit, a first portion of the fluid stream expelled from the bit is directed substantially forward of the slant faced head and a second portion of the fluid stream is directed substantially rearward from the slant faced head.

A percussive rock drill bit includes a head having an annular gauge collar and a central island. An annular cutting channel is defined between the collar and the island such that specifically positioned cutting buttons are effective to create an annular ridge in the cut rock face having a reduced rock breaking resistance to increase the rate of drilling and/or decrease the required power consumption.

A percussive rock drill bit includes a head having an annular gauge collar and a central island. An annular cutting channel is defined between the collar and the island such that specifically positioned cutting buttons are effective to create an annular ridge in the cut rock face having a reduced rock breaking resistance to increase the rate of drilling and/or decrease the required power consumption.

An internally threaded bit for percussion drilling is provided, which has thread roots wider than the thread crests. A single drill bit, configured according to the present invention, can be connected to a variety of rods, having differing crest widths in their male threads. The invention enables the service life of the rods to be optimized to suit the drilling conditions at hand, without the need to manufacture and keep in inventory a correspondingly large variety of drill bits. The bit of the invention exhibits a reduced rate of ringing off, and can accept drill rods having a range of crest widths.

An internally threaded bit for percussion drilling is provided, which has thread roots wider than the thread crests. A single drill bit, configured according to the present invention, can be connected to a variety of rods, having differing crest widths in their male threads. The invention enables the service life of the rods to be optimized to suit the drilling conditions at hand, without the need to manufacture and keep in inventory a correspondingly large variety of drill bits. The bit of the invention exhibits a reduced rate of ringing off, and can accept drill rods having a range of crest widths.

Systems for forming or extending a tunnel or shaft within geologic material may include a ram accelerator assembly for accelerating one or more projectiles into geologic material to weaken a region of the geologic material. The projectile(s) pre-condition the geologic material, such as by forming one or more holes in a central region of the material or to define a perimeter of the region to be displaced. A cutting tool or subsequent projectile impacts may then be used to remove the weakened material. The voids formed by the first projectile(s) cause compressive forces from subsequent impacts or cutting operations to be converted to tension forces that more efficiently break geologic material, which may fall into the voids created by the first projectile(s). The voids created by the projectile impacts may also control the material that is removed and the shape of a resulting section of the tunnel or shaft.

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).