Abstract: A improved "mud motor" for use in oil and gas well drilling includes a reciprocating valve and piston arrangement that generates power using drilling fluid media (e.g., drilling mud) pumped through an inlet port to form a differential across a piston seat. The differential pressure causes the valve and piston assembly to move down in an elongated body. Rollers then force telescoping, reciprocating fingers to rotate while absorbing the reciprocating up and down action of the valve and piston assembly. This clockwise rotation causes a transmission that includes a clutch shaft and sprags to engage a clutch housing causing the drill bit to turn. Thrust bearings allow weight to be applied to the tool to optimize drilling action. The apparatus can be used in well drilling or in the removal of obstructions such as bridge plugs, metal and rubber from the well bore.

Abstract: A compressor piston divides a first compartment into two compression chambers, while a hammer piston divides a second compartment into two drive chambers, each of the compression chambers being connected to a respective one of the drive chambers to form a closed fluid system wherein reciprocation of the compressor piston causes cyclic compression and expansion of the fluid in the compression chambers and thus in the drive chambers, to effect a cyclic impacting of the hammer piston with a bit adapter connected to the drill bit. A mud motor rotates a shaft to drive an oscillator which reciprocates the compressor piston. The oscillator can comprise roller elements in the compressor piston in engagement with canted grooves in the shaft. While drilling mud drives the motor and then passes downwardly to flush the drill bit and the borehole, the drilling mud is isolated from the closed fluid system.

Abstract: An impact driven oil and gas well tool for use with an elongated tubular string having a central flow conveying bore is provided for channeling pressurized fluid to the tool body. The apparatus further includes an elongated longitudinally extending tool body having a connecting end portion at its upper end for connecting the tool body to the pipe string. A fluid chamber in the tool body is provided that is in fluid communication with the pipe string bore. A stem is reciprocally movable within the tool body in a telescoping fashion. The stem includes a lower end portion for carrying a working member such as a drill. A pressure responsive valve is provided for controlling relative movement of the stem and the tool body. An anti-chatter annular sleeve is positioned in the fluid chamber and about the valve member. A spring extends between the sleeve and the valve member for holding the valve member off the seat until a predetermined flow rate through the tool body is reached.

Abstract: Down-the-hole drilling machine comprising a housing (1) with a hammer piston (5) movable to-and-fro and intended to exert a drill bit (3) to impacts. The hammer piston is formed with two piston heads (6,7) and a waist (9) between them. An intermediate wall (10) is arranged around the waist (9) so that two chambers (11,12) are formed on either side of the intermediate wall. The chamber (11) between the intermediate wall and the forward piston head (6) is continuously pressurized via a first channel (13) in the intermediate wall. The chamber (12) is via a second channel (15) in the intermediate wall connected to a space (16) in front of the hammer piston (5). Through this double drive areas are obtained during the working stroke of the hammer piston.

Abstract: A compressor piston divides a first compartment into two compression chambers, while a hammer piston divides a second compartment into two drive chambers, each of the compression chambers being connected to a respective one of the drive chambers to form a closed fluid system wherein reciprocation of the compressor piston-causes cyclic compression and expansion of the fluid in the compression chambers and thus in the drive chambers, to effect a cyclic impacting of the hammer piston with a bit adapter connected to the drill bit. A mud motor rotates a shaft to drive an oscillator which reciprocates the compressor piston. The oscillator can comprise roller elements in the compressor piston in engagement with canted grooves in the shaft. While drilling mud drives the motor and then passes downwardly to flush the drill bit and the borehole, the drilling mud is isolated from the closed fluid system.

Abstract: A ram-boring machine with forward and reverse motion control which comprises a percussion piston that can be axially displaced in a tubular housing, a control tube that is arranged in the housing and controls the forward and reverse motion of the percussion piston by passing over radial control openings in the percussion piston, control edges on the control tube which are guided in the percussion piston in sealed fashion, a compressed air bore that runs into the front end of the control tube, a compressed air bore or compressed air line that runs into an annular chamber between a first control edge and a second control edge, an outlet bore or outlet line that originates in the region between the second control edge and a third control edge and leads to the rear end of the control tube, and control means for selectively charging the compressed air bore or compressed air line or ventilating the outlet bore or outlet line.

Abstract: An elongated tube has a high pressure feed line on one end and an impact head on the other end. A tube intermediate the ends of the tool houses two cylinders having one piston is in each cylinder. The two pistons are tied together by a piston rod extending through a bulkhead dividing the two coaxially aligned cylinders.

Abstract: The present invention relates to a hammer device, preferably a down-the-hole hammer, including a drill bit (11) and a piston (10) reciprocating therebehind to periodically strike the drill bit. The drill bit (11) includes front (11a) and rear (11b) portions of different impedance, and the piston (10) includes front (10b) and rear (10a) portions of different impedance. In the drill bit, the front portion (11a) has a larger impedance than the rear portion (11b). In the piston, the rear portion (10a) has a larger impedance than the front portion (10b). The length of the drill bit front portion (11a) is about twice the length of the drill bit rear portion (11b). The length of the piston rear portion (10a) is about twice the length of the piston front portion (11b). The invention further relates to a drill bit (11) and a piston (10), per se.

Abstract: A dual acting hydraulic jarring enhancer which is particularly well suited for coiled tubing application. A common annular chamber is formed between reciprocating cylindrical assemblies, and a piston is positioned within the annular chamber. The inner cylindrical assembly has a member to contact the piston and move it relative to the outer cylindrical assembly in one direction while the outer cylindrical assembly has a member to prohibit longitudinal movement of the piston relative to the inner cylindrical assembly in a second direction. In this manner, the present invention provides a tool with overall minimal length by using a singular annular chamber capable of being divided into two other chambers and providing an accelerating effect to a hammer/anvil of an associated jarring tool in either an upjarring or downjarring mode.

Abstract: An elongated tube has a high pressure feed line on one end and an impact head on the other end. A tube intermediate the ends of the tool houses two cylinders having one piston is in each cylinder. The two pistons are tied together by a piston rod extending through a bulkhead dividing the two coaxially aligned cylinders.

Abstract: An accelerator having a tubular housing and a tubular mandrel substantially coaxial arranged for telescoping longitudinal movement within the tubular housing, the accelerator also including: a first piston positioned radially between the tubular housing and mandrel, the first piston being adapted for movement with the mandrel in response to movement of the mandrel in a first longitudinal direction relative to the housing and adapted to resist longitudinal movement in response to movement of the mandrel in a second longitudinal direction relative to the housing; and a second piston positioned radially between the tubular housing and mandrel, the first and second pistons forming a substantially sealed gas chamber therebetween, the second piston being adapted for movement with the mandrel in the second longitudinal direction relative to the housing and adapted to resist longitudinal movement in response to movement of the mandrel in the first longitudinal direction relative to the housing, and whereby the chambe

Abstract: A percussion tool includes a housing part having a frontal end provided with an opening; a tool bit guide supported in alignment with the opening; and a tool bit slidably supported in the tool bit guide and projecting from the housing part through the opening. The tool bit is arranged for a reciprocating motion parallel to the longitudinal tool bit axis and transverse excursions substantially perpendicular to the tool bit axis. A transverse guide is attached to the housing part and displaceably receives an outer seal composed of a transverse slide. The transverse slide has an aperture through which the tool bit passes. The transverse slide and the tool bit are arranged such that the transverse slide and the tool bit move as a unit during the transverse excursions of the tool bit. There is further provided an inner seal disposed in the housing part between the transverse slide and the tool bit guide externally thereof.

Abstract: An overburden drilling device includes a drill bit body, a percussion element for applying impacts to the body, and a casing attached to the body. The casing is connected to the drill bit body by a casing shoe which comprises semi-cylindrical halves which are held together by a circular ring that is welded to the halves. The casing shoe and the drill bit body are interconnected by radially overlapping walls so that the drill bit body pulls the casing along during a drilling operation.

Abstract: An elongated tube has a high pressure feed line on one end and an impact head on the other end. A tube intermediate the ends of the tool houses two cylinders having one piston is in each cylinder. The two pistons are tied together by a piston rod extending through a bulkhead dividing the two coaxially aligned cylinders.

Abstract: A down-hole pneumatic rotary-percussion hammer drilling apparatus is disclosed. The apparatus includes a drill string for progressively extending into a hole in the earth; an elongated housing connected to the drill string; an impact drill bit, rotationally coupled to the housing, having an engaging surface, an earth impacting surface, a channel, and a plurality of conduits extending from about an exit of the channel to an exit portion of the conduits; a piston within the housing for engaging the engaging surface; and a working fluid handler for energizing the piston with a working fluid. The impact drill bit is rotatable about a longitudinal axis, with the channel and the conduits providing a path of flow of the working fluid from the piston to the exit portions of the conduits. The exit portions are displaced from the longitudinal axis and extend generally downwardly and outwardly. The working fluid emerges from the exit portions and effects rotation of the impact drill bit about the longitudinal axis.

Abstract: A down hole hammer assembly for percussive drilling of ground holes has a drill bit slidably carried in a chuck housed within a barrel of the assembly. Drill bit travel is limited by a retainer sleeve in place about a reduced segment of the drill bit. The sleeve includes a ring portion limiting bit travel and a skirt portion for confinement within a component of the hammer assembly to prevent loss of the retainer sleeve and drill bit during barrel separation.

Abstract: A double-acting hydraulic striking tool, wherein a hammer's (8) upper end (9) is rigidly connected to an upper piston (10), and wherein the hammer's (8) lower end (26) is rigidly connected to a lower piston (26). The pistons (10, 27), which can be displaced within a tubular housing (11), are adapted to open and close for a forced flow of liquid from the upper end (9) of the hammer (8) towards the lower end (26). The hammer (8) is activated for downwardly directed blows by pressing against the hammer's (8) upper end (9) with a resilient force, causing the lower piston (27) to close the liquid flow, whereby the housing (11) is lifted hydraulically until the piston (27) opens for the liquid flow, and the forced spring force drives the housing (11) downwardly to impinge on the hammer's (8) lower end (26) through impact faces (34, 36).

Abstract: An hydraulically driven percussive hammer for use with down-the-hole percussive hammer drilling, the hammer having a piston and liner combination which provides for multiple stages where there are successive effective piston drive areas of diminishing size for both return and impact directions which minimizes peak pressures from hydraulic hammer effects.

Abstract: An impact boring head may comprise a main body having an internal cavity with a front end and a rear end. A striker having a head end and a tail end is slidably mounted in the internal cavity of the main body so that the striker can be reciprocated between a forward position and an aft position in response to hydraulic pressure. A compressible gas contained in the internal cavity between the head end of the striker and the front end of the internal cavity returns the striker to the aft position upon removal of the hydraulic pressure.

Abstract: A jar enhancer including a housing in which is telescopically mounted a mandrel, with the mandrel rotationally locked within the housing, and the housing and mandrel being spaced apart by an amount R at one location between them to form a chamber of width R. The upper end of the chamber is closed by a face, at least part of which is a shoulder extending inward from the housing, and the lower end of the chamber is closed by a face, at least part of which is a shoulder extending from the mandrel. The housing is sealed to the mandrel above and below the chamber and a port is provided for filling the chamber with compressible fluid. At least one of the shoulders has width W less than R, such that only a part of one of the faces bounding the chamber moves upon relative movement of the mandrel in relation to the housing.

Abstract: A water driven hammer device has a machine housing and a hammer piston movable to-and-fro in the machine housing. The hammer piston is guided in the machine housing in two guides separated from each other. The guides are formed from two parts each having different inner diameters, and the parts with the largest inner diameters on the guide are turned towards each other. A room between the guides is pressurized and chambers on the other side of the guides are kept at a lower pressure, resulting in fluid flow through the guides for centering the hammer piston in the machine housing to avoid seizure of the hammer piston.

Abstract: A common problem with reverse circulation downhole hammers is retention of the sample tube that extends through the actual hammer component., There is a tendency for the sample tube to become loose in its mounting, and the resulting movement through vibration results in accelerated wear which rapidly leads to failure of the component In this application, the sample tube for use in a reverse circulation downhole hammer comprises a sample tube that has a lower end connected to a drill bit sample delivery aperture and an upper end connected to a drill string sample delivery tube. The sample tube has at least one projection intermediate the upper and lower ends of the sample tube that has a non-circular cross section extending radially from the sample tube. The projection locates within a recess that has a corresponding cross sectional shape, the recess being fixed with respect to the hammer to prevent rotation of the sample tube with respect to the hammer.

Abstract: The present invention relates to building and to mining, more particularly o an apparatus for impact action designed for trenchless laying of new underground communications and for reconstruction of existing communications, the apparatus comprising a body, a striker with a through central channel, the striker positioned inside the body with the possibility of performing reciprocal movement, a front chamber formed between the body and striker, a rear chamber formed between the body and the striker, an air distribution system comprising channels for the inlet of compressed air into the chambers and channels for the exhaust of spent air from the chambers, an air conduit, and in which in accordance with the invention the air distribution system is provided autonomously for each of the aforesaid chambers.

Abstract: A chuck and drill bit combination for insertion into a front end of a percussive, down the hole drill forming a part of a cluster drill assembly, for selectively engaging and disengaging the chuck and drill bit during drilling operations includes the bit and chuck each having splines and grooves adapted to overlap and engage each other in a first stop position and further adapted to disengage from each other in a second stop position, whereby the bit is restrained from rotational movement but capable of axial movement in the first stop position and capable of both axial and rotational movement in the second stop position, to provide automatic indexing of the bit so as to position the bit's gage drilling buttons in a preferred position outboard of the drill centerline, to maintain maximum borehole diameter.

Abstract: A make-up system of a down-the-hole hammer. The down-the-hole hammer is of the type comprising a hammer casing (111) having a top sub (112) mounted to one end and a drill bit chuck mounted to the other end. The casing accommodates a piston which is caused to reciprocate within the hammer casing.

Abstract: An in-hole rock drilling machine has a hydraulic impact motor within a housing. The hydraulic impact motor has a spool valve contained within a valve housing. The spool valve has two operating positions to alternately pressurize and depressurize a drive chamber to reciprocate a hammer. The spool valve has a continuously pressurized third control surface that biases the spool valve towards a second operating position, a first control surface that acts opposite the third control surface to move the spool valve to a first operating position, and a second control surface that acts with the third control surface to return the spool valve to the second operating position. The valve housing guides the rear portion of the hammer, and a guide bushing guides the front portion of the hammer. The guide bushing, valve housing, and a distance sleeve are clamped against a shoulder of the housing.

Abstract: An apparatus and method for delivering a jarring action to an object in a well bore is disclosed. Generally, the apparatus comprises a cylindrical housing, with the cylindrical housing being connected to the stuck object; and, a power mandrel disposed within said cylindrical housing, with the power mandrel being threadedly connected to a work string. The invention also includes a latch member adapted to the housing, and a collet member having an end engageable with the latch. A conical member is adapted to set, reset and unlatch the engageable end of the collet. Also included will be an activation piston cooperating with the conical member.

Abstract: A bit retention device for a bit and chuck assembly of a down-the-hole, percussive drill, for retaining a head section of a bit should the head section separate from a shank of the bit includes a chuck adapted for threadable connection to a drill casing, a drill bit, a bit retaining shoulder in the the assembly; a wear collar concentric about the chuck and bit and a flexible retaining member removably connected to the assembly, the retaining member extending radially between the wear collar and bit a sufficient distance to contact the retaining shoulder should the bit drop axially downwardly.

Abstract: The invention provides a method for reversing an impact boring tool of the type having a reversing mechanism actuated by rotation of the compressed air supply hose that enters the tool through a rear end opening. This method includes the initial step of connecting the air supply hose to the tool using a quick-release coupling device including tubular male and female members which are coupled together, one of the members being mounted on the end of the air supply hose and the other mounted on an air inlet conduit of the tool, the coupling device further having a locking sleeve and a ball seated in a first pit in one of the members and configured for insertion into a second pit in the other of the members as the locking sleeve moves over the ball, the locking sleeve being biased to a locked position wherein the ball is seated in both pits thereby preventing rotation of one member relative to the other as well as disengagement of one member from the other.

Abstract: A reverse circulation down-the-hole drill includes an outer wear sleeve (1) and a backhead (2) assembly located at one end of the outer wear sleeve (1) for connecting the drill to a double-walled drill string and to a source of pressure fluid to actuate the drill. A fluid diverter (5) is mounted inside the outer wear sleeve (1) adjacent to the backhead (2). An inner tube (9), concentric with the outer wear sleeve (1) and extending into the fluid diverter (5), defines at least part of a central return passageway in the drill. A bit (10), located by a chuck (3) at the other end of the outer wear sleeve (1), is slidably mounted on the inner tube (9) in an annular chamber (28, 30) defined by the outer wear sleeve, by the inner tube, by the diverter at one end (28), and by the bit at the other end (30).

Abstract: A device for use within the backhead of a down hole percussive drill, for removing debris from a drillhole, includes a flow control member in the drill backhead for inducing cyclonic flow of percussive fluid, to concentrate the heavier water and other matter away from the lighter percussive gases, a separator in the backhead that separates the water and other matter, passageways in the backhead for ejecting the separated water and other matter, a sealing member for sealing the backhead passageways against back flow of debris from the drillhole annulus, and an indexing member for positioning the separator so as to permit a pre-selection of flow amounts of removed water and other matter.

Abstract: A hydraulic reciprocating percussion tool, particularly adapted for drilling applications, comprises an elongated cylinder, opposed fronthead and backhead members and a central bore in the cylinder for supporting a reciprocating piston hammer. The piston hammer has reduced diameter end portions which have respective tubular sleeve valves disposed in sleeved relationship thereon and engageable with valve retainer members on the reduced diameter portions for effecting movement of the valves with the piston hammer. The head members include tubular sleevelike stem portions which cooperate with the respective valves to valve pressure fluid to and from opposed chambers in the cylinder to effect repeated impact blow delivering strokes to a shank member disposed in a chuck connected to the fronthead.

Abstract: A compressor piston divides a first compartment into two compression chambers, while a hammer piston divides a second compartment into two drive chambers, each of the compression chambers being connected to a respective one of the drive chambers to form a closed fluid system wherein reciprocation of the compressor piston causes cyclic compression and expansion of the fluid in the compression chambers and thus in the drive chambers, to effect a cyclic impacting of the hammer piston with a bit adapter connected to the drill bit. A mud motor rotates a shaft to drive an oscillator which reciprocates the compressor piston. The oscillator can comprise roller elements in the compressor piston in engagement with canted grooves in the shaft. While drilling mud drives the motor and then passes downwardly to flush the drill bit and the borehole, the drilling mud is isolated from the closed fluid system.

Abstract: An in-the-hole hydraulic hammer drill of the type having an inlet passageway for fluid and connectible to a drill string providing a source of pressurized fluid, and having pistons capable of providing downwardly directed impacts onto anvils solidly connectible to a drill bit, and having valves operated automatically by movement of the pistons to provide a continuous cycle of operation. The pistons include an upper piston and a lower piston, each capable of impacting respective upper and lower anvils solid with the drill bit, and the valves means include an inlet valve situated at the junction of the lower end of the upper piston and the upper end of the lower piston and closable by the coming together of the upper and lower pistons, and an outlet valve at the lower end of the lower piston and having a valve member operated by the lower piston.

Abstract: A reverse percussion device for use with hydraulic percussive drills is provided. The reverse percussion device includes a cycling piston, valve and anvil. The piston and valve move in opposing directions between low and high pressure passages automatically until a lodged drill bit is freed, thereby facilitating removal of the drill bit from the drilled hole and eliminating alternate loosening and tightening of drill string threads. The reverse percussion device preferably includes an automatic disabling feature which causes the reverse percussion operation to cease when the bit is free to retract normally.

Abstract: There is disclosed a single-acting hydraulic jar having upper and lower detent pressure chambers having upper and lower restrictions, respectively, formed on the inner diameter of its outer tubular member and through which upper and lower detent means carried about the outer diameter of the inner tubular member may be moved in order to impart an up jar.

Abstract: A reversible casing for a fluid-actuated, percussive, down-the-hole drill is provided with a tubular body having an internal surface forming a bore extending along a longitudinal axis. The internal surface has a profile that is a mirror image about a centerline axis perpendicular to the longitudinal axis. The profile is provided with alternating undercut portions and land portions, with a portion of the undercut portions being in an annular scalloped configuration comprising a plurality of longitudinally extending parallel grooves in the internal surface.

Abstract: According to the invention, a drill hammer (10) generally comprises an outer tube (55), a control casing jacket (60) inclusive of check valve (59) and a central tube (80) having radial passages (81, 83). A ram (75) is guided on central tube (80), onto the lower and preferably recessed end (84) of which the head of a drill steel (90) may slide. A cylinder liner (70) that may be provided with outer ribs (101) also guides ram (75) and is peripherally welded to outer tube (55) along a welding zone S of axial length l. Above control casing jacket (60), there is an adapter (40) comprising downstream channels (43) and carrying a blowing collar (50) provided with upwardly directed nozzles (53). A drive-transmitting sleeve (15) below a screw head (11) is joined to the adapter (40) either directly or via a shift unit (30) that guides a shaft (20) whose lower end (23) may form a slide valve relative to an upper adapter portion (41). From there, passages (42, 47) lead to a control casing jacket (62) having channels (63).

Abstract: A fluid-actuated, percussive, down-the-hole drill having a piston slidingly supported in a casing and passageways for transmitting flow of percussive fluid to actuate the piston is provided with self-lubricating bearings and self-lubricating seals within the drill to provide a drill requiring no oil lubrication.

Abstract: A drilling arrangement is provided having a reciprocating piston hammer which hammers a drill bit for hydraulic down-the-hole piston hammer drilling. The drilling arrangement uses a liquid for driving the reciprocating piston hammer with respective impacting facing surfaces between the hammer and the drill. The respective impacting facing surfaces are formed such that at the moment of impact some of the liquid is forced between the impacting surfaces. This substantially reduces if not eliminating altogether the cavitation which might otherwise develop.

Abstract: A hydraulically operated mole has a reciprocating hammer operated by means of an impact mechanism which may be readjusted from forward to backward wiring by displacement of a valve tube secured to a piston near the rear end of the apparatus. The piston is activated by the switching of oil supply and withdrawal respectively to the tank between two pipeline stubs at the rear end of the apparatus. The fluid connections between the stubs and the piston are completely separated as regards the flow. As a result, complicated and vulnerable valve elements used in known hydraulic moles are avoided.

Abstract: A drill bit is mounted for percussive reciprocal movement in the lower end segment of a drill wear tube. A barrel is in the wear tube and defines a first and second series of exhaust ports. Channels in the barrel communicate the exhaust ports with discharge openings spaced about the head of the drill bit. An inlet opening in the face of the drill bit receives airborne earthen particles carried to an evacuation tube. Keys and keyways are disposed about the drill bit in parallel with the drill bit axis permitting a passageway of optimum size. Disposed within the barrel is a tubular piston which reciprocates in response to pressurized air alternately directed to the piston ends. The piston ends open and close the barrel exhaust ports. Internal surfaces of the piston cooperate with surfaces on the evacuation tube and on a press fitted sleeve thereon to direct compressed air to the piston ends.

Abstract: A method and apparatus for jarring an object in a wellbore is disclosed. Generally, the apparatus contains a body member having an inner and outer diameter, an operator mandrel slidably disposed within the inner diameter of the body member, and a selective attachment member for selectively attaching and detaching the operator mandrel to the body member. The apparatus may also contain a mechanism to reset the operator mandrel with the body member when the operator mandrel has been released.

Abstract: A drill stem arrangement and method in which the motor for providing the hammer action is in the drill stem near to the drill bit. The motor is driven by pressurised liquid and a proportion of the liquid is used for flushing drill cuttings and cooling the drill bit.

Abstract: A hydraulic jar device for use in connection to coil tubing which consists of an elongate tube having an upper hammer sub, a kelly cylinder and a hydraulic cylinder with central restrictor. A lower sub connects to the bottom end of the hydraulic cylinder. The sliding interior components are an upper mandrel secured to an anvil sub which, in turn, is fastened to an axial plunger, all of which are slidable down within the elongate tube. A guide means prevents relative rotation between the mandrel and the elongate tube consisting of hammer sub, kelly cylinder, hydraulic cylinder and lower sub. A metering ring retained on the plunger interacts with the central restrictor of the hydraulic cylinder to control force effected up and down jars that occur when the mandrel strikes the hammer sub on the down stroke, and when the anvil sub strikes the hammer sub bottom on the up stroke.

Abstract: A pneumatic impact tool useful in pipe insertion operations has a simplified construction as compared to the pneumatic ground piercing tools currently in use for such operations. The body of the tool is a thin walled sleeve clamped between a nose section and an end plate by one or more tying devices such as rigid metal tie rods. This eliminates the need for a thick walled tool body having a tapered nose as is common in existing tools made to move through the soil.

Abstract: Fluid driven down-the-hole drilling machine. The hammer piston (2) of the down-the-hole drilling machine is adjacent to its front end provided with a cylindrical part (6). The drill bit (3) is provided with a first impact surface (41) which receives impacts during drilling, a second impact surface (42) and an annular section (7) which surrounds the cylindrical part (6) between the impact surfaces. The second impact surface (42) receives the impact energy of the hammer piston at reversed feeding of the housing (1) of the down-the-hole drilling machine for freeing the drill bit when it has become stuck.

Abstract: Rock drilling device for drilling with a drill string comprising a set of tubes (1) and a set of rods (2) arranged centrally in the set of tubes.

Abstract: The present invention relates to a sacrificial transmission sleeve for a reverse circulation down hole hammer of the percussive type actuated by a fluid under pressure, including an outer sleeve, a drill bit retained in retaining means, the transmission sleeve comprising a body and an annular flange extending from the body towards the drill bit, wherein the transmission sleeve has an outer diameter greater than that of the outer sleeve and substantially the same as the drill bit.

Abstract: An air percussion hammer drill is disclosed for operation in an earthen formation. The air compression hammer mechanism comprises a piston that reciprocates while simultaneously rotating within its housing. A hammer drill bit slidably keyed to the bottom of the piston transfers the impact energy to the formation and rotates during operation independent of an attached drill string. The air percussion hammer assembly is therefore ideally suited to directional drilling activities.