Abstract: The present invention generally relates to an apparatus and method of jarring with an overpull generator. In one aspect, a method of dislodging an object stuck in a wellbore is provided. The method includes the step of running an assembly into the wellbore on a conveyance member and attaching the assembly to the object, wherein the assembly comprises an overpull generator and a delay force release device. The method also includes the step of generating an overpull force in the wellbore by selectively activating the overpull generator. Additionally, the method includes the step of applying an impact force to the object by activating the delay force release device and releasing the generated overpull force, thereby dislodging the object stuck in the wellbore. In a further aspect, an assembly for dislodging an object stuck in a wellbore is provided. In yet a further aspect, an overpull generator for use in generating an overpull force in a wellbore is provided.

Abstract: A pneumatically reversible ram boring device includes a percussion piston (8) that is situated in a casing (1) and is movable back and forth by operation air supplied via an operational-air supply via an operational-air line (5), a control pipe (4, 36, 54) having at least one control opening (13), an outer pipe (15, 65), and a control sleeve (10, 60) that can be displaced by compressed air from a control chamber (16, 66). An essentially torsion-resistant operational-air line (5) can be rotatably connected to a rotary valve (4, 40, 70) that supplies the control chamber with operational air or vents air from the chamber.

Abstract: Disclosed is an apparatus for vibrating a downhole drill string operable to have a drilling fluid pumped therethrough. The apparatus comprises a tubular body securable to the drill string and having a central bore therethrough, a valve in the tubular body for venting the drilling fluid out of the drill string and a valve actuator for cyclically opening and closing the valve. The method comprises pumping a drilling fluid down the drill string and cyclically venting the drilling fluid through the valve so as to cyclically reduce the pressure of the drilling fluid in the drill string. The valve may comprise a tubular body port and a corresponding rotor port selectably alignable with the tubular body port as the rotor rotates within the central bore. The valve actuator may comprise at least one vane on the rotor for rotating the rotor as the drilling fluid flows therepast.

Abstract: A force balancing system for use with a well bore tool, such as a drilling tool, is provided. The tool may be connected to a drill string, and the force balancing system is adapted to decouple the weight of the drill string from the operation of the tool. The force balancing system utilizes hydraulic or pneumatic pressure to advance the tool into the well bore, while preventing excessive weight from being applied to the tool.

Abstract: A double-acting jar is disclosed comprising: an outer housing; an inner mandrel at least partially disposed telescopically within the outer housing to define a fluid chamber between the inner mandrel and the outer housing, the fluid chamber containing fluid and being sealed; a valve disposed within the fluid chamber on one of the inner mandrel and the outer housing; the valve having a downhole portion that is movable between a downhole seated position in which the valve seats against the one of the inner mandrel and the outer housing and an unseated position, the downhole portion having a downhole restriction surface; the valve having an uphole portion that is movable between an uphole seated position in which the valve seats against the one of the inner mandrel and the outer housing and an unseated position, the uphole portion having an uphole restriction surface; the other of the outer housing and the inner mandrel having a cooperating restriction surface that cooperates with the downhole restriction surfac

Abstract: There is provided a downhole hammer including a drill bit (2) retained by short (4) and long (5) drive pins in the bore of a driver chuck (1). The chuck (1) and bit (2) shank have machined longitudinal grooves (3), every second bit shank groove being blind and connected to the adjacent open groove by a short-pin-length relief. The shorter pins (4) are inserted into the visible holes formed by the alignment of the open drill bit grooves and driver chuck grooves (3). The chuck (1) is then indexed which shunts the short pins (4) sideways until the longer pins (5) are insertable. The driver chuck (1) and drill bit (2) are engaged rotationally. The bit (2) slides by the desired distance due to the shorter pins (4) being entrapped in the blind grooves. The arrangement does not require a bit shank extension to accommodate a conventions bit retainer ring.

Abstract: A pneumatically operated underground piercing tool including an elongate cylindrical body carrying an anvil and a striker slidably received within a chamber. A valve assembly controls the communication of pressurized air to and from the body and is operator adjustable in order to produce forward or rearward movement of the piercing tool. The body and an end cap are connected by a tapered buttress thread. The striker defines a plurality of balancing grooves. A recess is formed in an end wall of the striker to inhibit pressurized fluid from being trapped between the striker and the end cap when the striker is reciprocated within the body. A tail adaptor is threadedly secured to the end cap using tapered buttress thread configurations. The valve assembly includes a detent mechanism and an improved exhaust bushing. The control spool is coupled to an end of said valve support by structure which includes a spherical element held in an elastomeric socket.

Abstract: A bit assembly is for a percussive drill that includes a casing with an interior chamber and includes a bit connectable with the casing and having a longitudinal bore and an axis through the bore. The bore has a retainer portion with one or more generally conical inner surfaces extending circumferentially about and facing generally toward the axis. A generally cylindrical valve has a longitudinal passage with an inlet fluidly connectable with the casing chamber and an outlet fluidly connectable with the bit central bore and an axis through the passage. An engagement portion with at least one generally conical outer surface extends circumferentially about and faces generally away from the valve axis. The valve engagement portion is disposable within the bit bore retainer portion such that the valve conical outer surface is disposed within and against the bit conical inner surface to retain the valve coupled with the bit.

Abstract: A variable frequency down hole drill, includes a drill bit, a reciprocating piston operable to deliver an impact load to the drill bit, and means for changing the frequency with which the piston delivers impact loading to the drill bit, also resulting in a change in overall power of the drill. The means for changing frequency and overall power may operate during continuous operation of the drill. The means for changing the frequency and overall power may include a valve for selectively changing the effective volume of a drive or return chamber, an actuator for changing the timing of placing the drive or return chamber in communication with exhaust, or a system for changing the frequency in response to sensing an predetermined operating parameter of the drill, such as pressure or piston position.

Abstract: A hydraulic jar for a drilling assembly is disclosed. In some embodiments, the hydraulic jar includes a tubular housing, a mandrel disposed in the housing, an annulus between the mandrel and the housing, and a pressure relief mechanism disposed in the annulus. The pressure relief mechanism generally divides the annulus into first and second portions. The pressure relief mechanism includes first and second annular members in engagement with one another when the pressure in the second annulus portion is less than a predetermined value and a fluid flow path between the first and second annulus portions. The fluid flow path has a first size when the pressure in the second annulus portion is less than the predetermined value, and a second size that is larger than the first size when the pressure in the second annulus portion becomes equal to or greater than the predetermined value.

Abstract: A percussive drill bit provided with an improved chuck assembly for a down-the-hole drill hammer. The bit has a head at its forward end with a shank extending from the head. The shank is screw threaded along its length. A reciprocating chuck is provided as a sleeve with internal screw thread as corresponding to those of the shank. The shank is releasably secured in the chuck with the read end of the shank providing a striking face. An arrangement of external splines on the chuck, and a retaining shoulder at its rear end, provide for the required guided movement of the chuck within a drill hammer wear sleeve.

Abstract: A percussive assisted rotary drill includes a top sub for connection with a drill pipe. The drill pipe imparts torque to the drill and also supplies motive fluid to the drill. The drill includes a shank adapter to facilitate affixing a rotary drill bit to the drill. The motive fluid is divided between a bit flow which flows through the bit to clear debris at the bottom of the drill, and an actuator flow. An actuator, which may be in the form of a reciprocating piston, moves within the drill under the influence of the actuator flow to impart cyclical blows to the shank adapter. The blows are transferred to the drill bit through the shank adapter to provide a relatively high frequency low amplitude percussive force on the rotating drill bit to assist in the drilling operation. At least a portion of the actuator flow portion of the motive fluid is exhausted through the top end of the drill.

Abstract: A DHD hammer that can exhaust working air volumes partially through a proximal end of the DHD hammer's actuator assembly includes a drive chamber, a return chamber, and a backhead that includes exhaust ports. Working air volumes from the drive chamber are exhausted through the backhead while working air volumes from the drive chamber are exhausted primarily through a drill bit.

Abstract: A percussion drilling assembly for drilling through earthen formations and forming a borehole. In an embodiment, the percussion drilling assembly comprises a fluid conduit including a tubular body having a first end, a second end, a through passage extending between the first end and the second end, and an inlet port in fluid communication with the through passage. In addition, the percussion drilling assembly comprises an adjustable choke at least partially disposed in the through passage and including a first bypass port. The adjustable choke is adapted to decrease the volumetric flow rate of a compressed fluid through the first bypass port.

Abstract: A down-the-hole assembly includes a housing assembly having a head end and a bit end. The housing assembly further includes an inlet joint having an inlet channel defined therein, a sealing portion positioned toward the bit end relative to the inlet joint, and an outlet portion positioned toward the bit end relative to the sealing portion. A hammer assembly including a piston has a piston channel defined therein that includes an inlet in fluid communication with the inlet channel and an outlet in fluid communication with the housing assembly.

Abstract: An expandable reamer apparatus and methods for reaming a borehole, wherein a laterally movable blade carried by a tubular body may be selectively positioned at an inward position and an expanded position. The laterally movable blade, held inwardly by blade-biasing elements, may be forced outwardly by drilling fluid selectively allowed to communicate therewith by way of an actuation sleeve disposed within the tubular body. Alternatively, a separation element may transmit force or pressure from the drilling fluid to the movable blade. Further, a chamber in communication with the movable blade may be pressurized by way of a downhole turbine or pump. A ridged seal wiper, compensator, movable bearing pad, fixed bearing pad preceding the movable blade, or adjustable spacer element to alter expanded blade position may be included within the expandable reamer. In addition, a drilling fluid pressure response indicating an operational characteristic of the expandable reamer may be generated.

Abstract: A percussive drill bit provided with an improved chuck assembly for a down-the-hole drill hammer. The bit has a head at its forward end with a shank extending from the head. The shank is screw threaded along its length. A reciprocating chuck is provided as a sleeve with internal screw thread as corresponding to those of the shank. The shank is releasably secured in the chuck with the read end of the shank providing a striking face. An arrangement of external splines on the chuck, and a retaining shoulder at its rear end, provide for the required guided movement of the chuck within a drill hammer wear sleeve.

Abstract: A water hammer using a drive rod is provided.

Abstract: The invention relates to a drill bit assembly for fluid-operated percussion drill tools comprising a percussion bit (1) having a head portion (3) formed with an axially extending stub shank (32). The stub shank is provided with axially extending splines (36), which are slideably engageable with complementary splines (35) formed on a drive chuck (4). Rotational drive from the chuck (4) may be transmitted to the stub shank (32) by means of the splines. Bit retaining means (6, 7, 41, 42) at the chuck are adapted for engagement with complementary retaining means (37, 51) at a spline portion of the stub shank to retain the stub shank in the drill bit assembly. Engagement means on the chuck (4) are adapted for connecting the chuck (4) to a drive means (5) of the fluid-operated percussion drill tool.

Abstract: A down-the-hole drill hammer is provided that includes a housing, a solid core piston mounted within the housing, a seal located between the solid core piston and the housing, and a backhead configured to exhaust working fluid volumes about a proximal end of the DHD hammer. The backhead includes a check valve assembly having a plug seal that can be moved to a closed seal position by gravity. A DHD hammer having a segmented chuck assembly is also provided. The segmented chuck assembly includes a plurality of chuck segments forming a cylindrical chuck assembly.

Abstract: A downhole percussive tool is disclosed comprising an interior chamber and a piston element slidably sitting within the interior chamber forming two pressure chambers on either side. The piston element may slide back and forth within the interior chamber as drilling fluid is channeled into either pressure chamber. Input channels supply drilling fluid into the pressure chambers and exit orifices release that fluid from the same. An exhaust orifice allows additional drilling fluid to release from the interior chamber. The amount of pressure maintained in either pressure chamber may be controlled by the size of the exiting orifices and exhaust orifices. In various embodiments, the percussive tool may form a downhole jack hammer or vibrator tool.

Abstract: In representative embodiments, a backhead for a drill assembly comprises an elongate member having a proximal end connectible to a source of pressurized fluid, a side wall defining an axial bore and an open distal end. A portion of the bore extending proximally from the distal end has an inner surface defining a cylinder portion shaped to receive an axially movable piston. The axial bore also comprises a check valve receiving area shaped to receive a check valve and to separate, during normal operation when a check valve is received in the check valve receiving area, an inlet area extending proximally to the proximal end from the cylinder portion extending distally to the distal end. Various improvements in retaining the distributor and increasing flow efficiency are described.

Abstract: A drilling system, including: a drill bit; and a thruster to apply a force to the drill bit. The thruster may include: an inner tubular member disposed within and configured to axially move within an outer tubular member; a thrust piston to transmit a hydraulic force to the inner tubular member, the thrust piston separating an upstream fluid chamber and a downstream fluid chamber between the inner and outer tubular members; at least one pressure switch fluidly connected to the downstream fluid chamber to control flow of a fluid to and from the downstream fluid chamber via at least one fluid inlet and at least one fluid outlet.

Abstract: A bidirectional drilling jar, capable of repeated unidirectional firing, including a sliding assembly that is disposed in a sliding relation to the interior of a barrel assembly. A portion of the inner diameter of the barrel assembly forms a restricted barrel segment. The restriction intermediate an upper chamber and a lower chamber. A metering system comprising an upper flange a meter valve, and a lower flange. The meter valve slideably disposed on the sliding assembly between the upper and lower flanges. The metering system travels between the upper chamber and the lower chamber providing limited, controlled flow of the fluid contained therein when passing through the restriction in order to pressurize the system and produce a jarring stroke. Alternatively, the metering system comprises an upper flange, a meter ring, a meter valve, and a lower flange. The meter valve and meter ring are slideably disposed on the sliding assembly intermediate the upper and lower flanges.

Abstract: According to one aspect of the invention hydraulic pressure pulses are created in a rock drill machine utilizing a rod (7, 7a, 7b) made of a magnetostrictive material arranged in one or more actuators (5, 5a, 5b), which exposes an impulse piston (3) in a pulse cylinder (1) to said hydraulic pressure pulses, whereby mechanical pressure pulses being transferred to a drill steel of the rock drill machine are generated in the impulse piston (3).

Abstract: In representative embodiments, a backhead for a drill assembly comprises an elongate member having a proximal end connectible to a source of pressurized fluid, a side wall defining an axial bore and an open distal end. A portion of the bore extending proximally from the distal end has an inner surface defining a cylinder portion shaped to receive an axially movable piston. The axial bore also comprises a check valve receiving area shaped to receive a check valve and to separate, during normal operation when a check valve is received in the check valve receiving area, an inlet area extending proximally to the proximal end from the cylinder portion extending distally to the distal end. Various improvements in retaining the distributor and increasing flow efficiency are described.

Abstract: A percussion drill, and methods of using the same, including a shank in mechanical alignment with a piston-hammer and a valve in fluid communication with the piston-hammer. The percussion drill further includes an internal hydraulic dampening system for reducing the velocity of the piston-hammer when the shank is forward of a power position relative to the velocity of the piston-hammer when the shank is in a power position. Preferably, the internal hydraulic dampening system includes mechanical alignment of a portion of the piston-hammer with a port in fluid communication with the valve, operable to reduce fluid flow into an area surrounding the valve when the piston-hammer is forward of its position relative to its normal operation.

Abstract: A percussion device (1) with a reciprocating percussion piston (3), includes a first chamber (5) that can be pressurized for forward driving of the percussion piston (3) and a second chamber (8) that can be periodically pressurized for back-driving of the percussion piston (3). The percussion device includes at least one driving piston (7) arranged for actuating the back-driving of the percussion piston (3) wherein a portion of said driving piston (7) is arranged to enter into the second chamber (8) for pressure actuating on a driving surface of the driving piston by pressure medium being present in this chamber in the direction of back-driving, wherein the driving piston (7) includes means for back-driving co-operation with the percussion piston (3), and wherein the driving piston (7) is free for axial movement with respect to the percussion piston (3), opposite the direction of back-driving. The invention also concerns a method and a rock drilling machine.

Abstract: There is provided a down hole hammer having a drive sub or chuck (10) having splines (11), and a drill bit (13) having a bit shank (14) having longitudinal splines (23) extending toward a bit head (15) having a bit face (16) bounded by a series of gauge row mounting portions (17), each of which has a carbide button insert (20). The bit shank splines (23) cooperate with chuck splines (11) to rotate the bit (13), the respective splines (23), (11) being proportioned to allow hammer motor exhaust air to pass down the splines. Drillings (37) are drilled from the termination of the spline milling, through to intersect with fluid passage (33) extending from sample recovery bore (22) to the bit face (16). A bore seal (32) is formed by milling a plurality of circumferential grooves (36), fed by a plurality of transverse holes (35) intersecting the air passage (33). Fluid passage (33) may be altered to fine tune the airflow to suit specific ground conditions, by effecting a change in diameter at point (38).

Abstract: A damping device for inserting into a housing of an impulse producing drill machine, for damping Shockwave reflexes from a drill string connected to the drilling machine, is distinguished in that a first damping piston (7) for direct or indirect action against the drill string and for applying a pressure in the direction of the drill string an a second damping piston (9) for applying pressure in the direction against the drill string against a fixed stop (11) arranged in the housing, wherein the first (7) and the second damping piston (9) are arranged to co-operate for joint damping action with a drill bushing or shank adapter in a certain relative position. The invention also concerns a drilling machine.

Abstract: A pressurized fluid flow system for a reverse circulation down-the-hole hammer comprising a cylinder (40) coaxially disposed in between the outer casing (1) and the piston (60); and two chambers (2, 3) defined by respective recesses on the inner surface of the outer casing (1) and separated by a dividing wall (5). During the operation of the hammer, the first chamber (2) is permanently connected to the source of pressurized fluid for supplying said fluid to a front chamber (240) and to a rear chamber (230) formed inside the hammer and located at opposite ends of the piston (60) for enabling it to reciprocate due to the changes in pressure of the pressurized fluid contained therein; and the second chamber (3) is permanently communicated with the bottom of the hole for discharging the pressurized fluid from said chambers (240, 230); wherein the flow into and out of said chambers (240, 230) is controlled solely by the overlap or relative position of the piston (60) and the cylinder (40).

Abstract: A downhole percussive tool is disclosed comprising an interior chamber and a piston element slidably sitting within the interior chamber forming two pressure chambers on either side. The piston element may slide back and forth within the interior chamber as drilling fluid is channeled into either pressure chamber. Input channels supply drilling fluid into the pressure chambers and exit orifices release that fluid from the same. An exhaust orifice allows additional drilling fluid to release from the interior chamber. The amount of pressure maintained in either pressure chamber may be controlled by the size of the exiting orifices and exhaust orifices. In various embodiments, the percussive tool may form a downhole jack hammer or vibrator tool.

Abstract: A downhole percussive tool is disclosed comprising an interior chamber and a piston element slidably sitting within the interior chamber forming two pressure chambers on either side. The piston element may slide back and forth within the interior chamber as drilling fluid is channeled into either pressure chamber. Input channels supply drilling fluid into the pressure chambers and exit orifices release that fluid from the same. An exhaust orifice allows additional drilling fluid to release from the interior chamber. The amount of pressure maintained in either pressure chamber may be controlled by the size of the exiting orifices and exhaust orifices. In various embodiments, the percussive tool may form a downhole jack hammer or vibrator tool.

Abstract: It is an object of the present invention to provide a more efficient and economically superior earth auger head in which a percussive excavation mechanism part (down-the-hole hammer) is incorporated in order to break up portions that are unsuitable for rotary excavation by the auger, and an excavation method using this auger head. The auger head comprises a rotary excavation mechanism part (1) in which a spiral vane (12) used for earth discharge is provided to the circumferential surface of a rotary tubular part (11), and in which an excavating bit (13) whose outer circumferential side protrudes further downward than the central side is provided to the lower end of this spiral vane; and further comprises a pneumatic percussive excavation mechanism part (2) that is installed inside the rotary tubular part and is disposed so that a percussive body (23) is accommodated in a position that is higher than the lower tip end of the excavating bit.

Abstract: The invention relates to a jar operated by fluid pressure, specially designed for use in drilling or maintenance operations carried out in oil or gas wells. The jar comprises a first (1) and a second (2) end piece, where the second end piece (2) comprises a jar shoulder (15), an inner, cylindrical string part (8) connected to a valve head (9) with a first valve surface (14), and to a weight (12), an outer, cylindrical string part (17), arranged axially movably to the inner cylindrical string part (8), and comprising a second valve surface (30), which is arranged to go into abutment against the first valve surface (14) on the valve head (9). The jarring function is achieved by the inner string part (8) and thereby the weight (12) being set in axial motion and striking the shoulder (15).

Abstract: An expandable reamer apparatus and methods for reaming a borehole are disclosed, including at least one laterally movable blade carried by a tubular body selectively positioned at an inward position and an expanded position. The at least one laterally movable blade, held inwardly by at least one blade-biasing element, may be forced outwardly by drilling fluid selectively allowed to communicate therewith or by at least one intermediate piston element. For example, an actuation sleeve may allow communication of drilling fluid with the at least one laterally movable blade in response to an actuation device being deployed within the drilling fluid. Alternatively, a chamber in communication with an intermediate piston element in structural communication with the at least one laterally movable blade may be pressurized by way of a movable sleeve, a downhole turbine, or a pump.

Abstract: The invention relates to a DTH-hammer drilling device, comprising a down-the-hole- (DTH-) hammer (6) with a percussion drill bit (9), a drill pipe (2) with a waste conduit for the cuttings and at least one supply conduit for the flushing medium and a flushing medium supply device, wherein a seal (18) for sealing the borehole against the borehole opening is provided in a fixed distance from the drilling head (6), or wherein a casing tube (12) is connected to the drill bit (9). The invention further relates to an overburden drilling method, comprising rotating a drill bit (9), supplying an energy transfer medium through a drill pipe (2) to the rotating drill bit (9) for transmitting a percussive action thereonto, dragging a casing tube (12) along with the drill bit (9) and flushing away cuttings through the drill pipe (2).

Abstract: In a reverse circulation down-the-hole hammer assembly a having a axially extending central tube (30) for recovery of drilling debris, the central tube (30) has a downwardly facing abutment (32) and an upwardly facing upper end and is located axially in the hammer assembly by having the part thereof between the downwardly facing abutment and the upper end located between axially spaced complementary abutments, one of which fixed and the other of which is provided by a resiliently longitudinally displaceable member (42) within a casing part providing an upper end of the hammer assembly and which is removably retained in an adjoining part of the hammer assembly. The longitudinally displaceable member engages the upper end of the central tube and thus clamps the central tube in place.

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 drilling apparatus includes a cutting structure defined by a percussive action cutter and at least one other cutter. The percussive action cutter is adapted to be urged in a drilling direction by hydraulic pressure force, while the other cutter is urged in a drilling direction by mechanical force.

Abstract: An impact enhancer apparatus includes: a substantially tubular inner member, a substantially tubular outer member that is axially movable in relation to the inner member, a primary energy storage device adapted to store energy when the inner member is moved in either of first and second axial directions with respect to the outer member and a secondary energy storage device adapted to store energy when the inner member is moved in a first axial direction with respect to the outer member. The primary energy storage device may include a primary biasing device. The secondary energy storage device may include a secondary biasing device. The primary and/or secondary biasing devices may be a spring device such as a disk spring, a coiled spring, a fluid spring, a gas spring, etc. The impact enhancing devices may include tubular members that have double shoulder high torque connections.

Abstract: A pneumatically reversible ram boring device includes a percussion piston (8) that is situated in a casing (1) and is movable back and forth by operation air supplied via an operational-air supply via an operational-air line (5), a control pipe (4, 36, 54) having at least one control opening (13), an outer pipe (15, 65), and a control sleeve (10, 60) that can be displaced by compressed air from a control chamber (16, 66). An essentially torsion-resistant operational-air line (5) can be rotatably connected to a rotary valve (4, 40, 70) that supplies the control chamber with operational air or vents air from the chamber.

Abstract: The invention discloses a fluid-driven impactor, a power transmission mechanism for the impactor and the use of the impactor. In the prior art, the working life of the impactor is short, since a rubber primary seal and an upper fluid-diverging lid for the fluid-driven impactor are both liable to erosion and the efficiency in transmitting power is low due to the complexity of the power transmission mechanism. In order to increase the drilling speed and/or extend the life of the impactor, the side cavity passage is formed in such a way that the inner wall of the outer pipe is isolated from the side cavity passage in a watertight manner without the use of the rubber primary seal. The loss in transmitting power is minimized by integrating the anvil of the power transmission mechanism and the lower joint.

Abstract: An axial bearing includes a first piston and a second piston. Axial contact surfaces between the pistons are arranged in the same pressure space. The same pressure fluid fed to the axial bearing acts on the contact surfaces and on working pressure surfaces of the pistons. A rock drilling machine is also provided with such an axial bearing.

Abstract: The device has a drill body, of generally cylindrical shape, connected by a flexible pipe to a high-pressure water pump placed on a low-height carrying vehicle. A striking piston is mounted movably, and is resiliently returned, in the drill body, and is subjected to a pulsed high water pressure so as to be moved with a percussive movement against a bit-carrying anvil, the pipe simultaneously transmitting to the drill body an alternating rotary movement about its principal axis. A solenoid valve, interposed between the pump and the point of departure of the pipe, receives successive electrical pulses causing opening and closing, which create shock waves in the water column contained in the pipe, which transmits these shock waves to the striking piston of the drill body. Applications: underground workings, mine workings, particularly for use in low-height galleries.

Abstract: A portion of a drilling tool having a drill bit driven in a rotating motion and in an axial percussion motion comprises a keyed connection between the drill bit and a driver sub that receives the drill bit. The keyed connection comprises a transverse member coupling the drill bit to a driver sub having a bore within which the drill bit is received. The driver sub has a pair of opposed openings and the bit has an axial slot. The openings and the slot are dimensioned to receive the transverse member. The keyed connection transmits force to the drill bit to drive the drill bit during operation and removably secures it in the driver sub.

Abstract: A pneumatically operated, deep hole rock drilling system for non-rotating drilling includes a pneumatically operated drive, a hammer sleeve with hammer mechanisms therein/connected thereto, a hammer bit below the hammer sleeve and a tube string above the hammer sleeve. The pneumatically operated drive includes a pneumatic pressure delivery mechanism and a drive piston. Further, this drive means has air flow channel means for delivery of air to the drive piston for reciprocally driving a hammer bit. The hammer bit has a convex bottom and a sidewall. The convex bottom has a plurality of impact buttons. The convex bottom has a center, with the sidewall being a predetermined distance X from the center.

Abstract: A drill bit assembly comprises a bit body intermediate a shank and a working face. The shank is adapted for connection to a drill string. The drill string comprising a fluid passage at least partially disposed within the body. A hammer assembly is movably disposed within the fluid passage along it central axis, the hammer assembly comprises a proximal end stabilized by a centralized upper bearing and a distal end stabilized by centralized a lower bearing. The distal end protrudes out of the working face and the hammer assembly comprises a carrier between the upper and lower bearings. Wherein, under normal drilling operations the carrier is adapted to resist a fluid pressure within the fluid passageway such that the fluid pressure will further extend the distal end of the hammer assembly from the working face by pushing on the carrier.

Abstract: In representative embodiments, a backhead for a drill assembly comprises an elongate member having a proximal end connectible to a source of pressurized fluid, a side wall defining an axial bore and an open distal end. A portion of the bore extending proximally from the distal end has an inner surface defining a cylinder portion shaped to receive an axially movable piston. The axial bore also comprises a check valve receiving area shaped to receive a check valve and to separate, during normal operation when a check valve is received in the check valve receiving area, an inlet area extending proximally to the proximal end from the cylinder portion extending distally to the distal end. Various improvements in retaining the distributor and increasing flow efficiency are described.

Abstract: In one aspect of the invention, a downhole tool string component comprises a fluid passageway formed between a first and second end. A valve mechanism is disposed within the fluid passageway adapted to substantially cyclically build-up and release pressure within the fluid passageway such that a pressure build-up results in radial expansion of at least a portion of the fluid passageway and wherein a pressure release results in a contraction of the portion of the fluid passageway. The valve mechanism disposed within the fluid passageway comprises a spring. Expansion and contraction of the portion of the fluid passageway varies a weight loaded to a drill bit disposed at a drilling end of the drill string.