Abstract: A directional drilling apparatus using a water hammer unit according to the present invention includes a hammer body in which a bit unit configured to perform boring work is installed to be movable upward and downward at an end portion of the hammer body, a piston slidably installed on the hammer body and including an operating fluid discharge part formed in a longitudinal direction, a drive unit installed between the hammer body and the piston to support an upper portion of the piston and configured to move the piston upward and downward using water supplied through a rod connected to the hammer body, a hammer unit including a rotary shaft coupled to a bit by a first coupling part so as to transmit a rotational force in a state in which the hammer unit passes through the piston installed on the hammer body and is moved upward or downward by the bit, and a mud motor unit coupled to the hammer body and configured to rotate the rotary shaft.

Abstract: A ball transfer mechanism for a harmonic drive and linear piston motor is disclosed. The ball transfer mechanism includes a spherical ball and a cylindrical seat portion. The seat portion defines a hemispherical shaped recess with a contour for receiving the ball. The ball transfer mechanism is in an exterior wall of a housing for converting rotary motion to linear motion, driving a linear piston motor. The harmonic drive drives a rotor of the linear piston motor. The harmonic drive includes a hollow cylindrical coupler portion engaging a rotor portion for transferring torque to the rotor portion. Transfer mechanisms disposed along a housing wall of the linear piston motor engage the coupler portion. The coupler portion includes harmonic cam grooves for receiving spherical balls in the ball transfer mechanism that drives rotational motion in the rotor in response to axially linear movement of the piston assembly.

Abstract: Assemblies and methods of use are disclosed for determining a position of a body within a tubing section. A signal generator coupled to the body is operable to generate a pressure wave in response to detecting a detectable portion of the tubing section when the body is moved relative to the tubing section.

Abstract: A downhole tool is disclosed herein that has an inlet for receiving fluid into a housing of the downhole tool. The downhole tool further includes a vibratory apparatus at least partially disposed within the housing of the downhole tool, the vibratory apparatus having an operational flow path disposed therein to operate the vibratory apparatus when fluid flowing through the operational flow path is above a predetermined pressure. Furthermore, the downhole tool has a bypass passageway disposed in the housing for providing an additional flow path for fluid through the downhole tool to prevent fluid from reaching the predetermined pressure in the operational flow path of the vibratory apparatus, the bypass passageway selectively blockable such that fluid in the operational flow path is increased above the predetermined pressure to activate the vibratory apparatus when the bypass passageway is blocked. A method of using the downhole tool is also disclosed.

Abstract: An unbalanced sub-assembly includes a turbine and a shaft coupled to the turbine at a first end of the shaft. The unbalanced sub-assembly is capable of rotating and imparting a vibration to the casing in response to a fluid being passed through the casing. A rupture disc is positioned on one end of the unbalanced sub assembly. The rupture disc is configured to rupture above a specified differential pressure threshold caused by fluid flowing through the vibration assembly. The rupture disc is capable of allowing the fluid to bypass the unbalanced sub assembly when the rupture disc is in a ruptured state. The rupture disc directs fluid through the unbalanced sub assembly when the rupture disc is in an un-ruptured state.

Abstract: A rotation guidance apparatus belonging to the technical field of oil drilling equipment. An end part of a lower connector has a ball-socketed ball-joint rod, and a drill bit is connected to the ball-socketed ball-joint rod. Several circumferentially and evenly distributed piston holes are provided in a side wall of the lower connector, wherein a piston matches each piston hole and a piston rod connected to the piston is movably connected to the ball-socketed ball-joint rod. An eccentrically-placed valve core is connected to a controller provided in an upper connector, wherein a working face of the eccentrically-placed valve core is opposite to the piston holes and rotation of the eccentrically-placed valve core makes the pistons in the piston holes move to control the rotation guidance of the ball-socketed ball-joint rod.

Abstract: A propulsion generator which employs one or more unbalanced rotors, such as fly wheels or other unbalance rotating members, which can be connected at a lower portion of a downhole coiled tubing string or other downhole tubular string for inducing propulsion of the coiled tubing. The unbalanced rotors may be oriented at different positions with respect to each other. The instantaneous fluid flow through the propulsion generator is substantially equivalent to the average fluid flow rate through the tool to provide relatively consistent fluid flow to downhole motors below the propulsion generator for operating the drill bit and/or cutters.

Abstract: A retainer and guide ring includes a first ring half and a second ring half that when placed adjacent to one another forms a complete ring. The retainer and guide ring also includes a kerf that is formed between ends of each of the first and second ring halves, which ranges from about zero inches to about 0.010 inches. In some exemplary embodiments, the retainer and guide ring is formed by obtaining two identical rings and making a cut along an edge of the diameter on each ring thereby forming a larger ring arc and a smaller ring arc for each of the rings. The two larger ring arcs are used to form the retainer and guide ring. In another exemplary embodiment, the retainer and guide ring is formed by obtaining a single ring and making a cut along the diameter.

Abstract: A method of running a bore-lining tubing string into a bore includes running a tubing string, typically a liner string, into a bore while agitating the string. The agitation may also take place while the tubing is being cemented in the bore. Pressure pulses may be applied to fluid in the bore, which fluid may be cement slurry.

Abstract: A retainer and guide ring includes a first ring half and a second ring half that when placed adjacent to one another forms a complete ring. The retainer and guide ring also includes a kerf that is formed between ends of each of the first and second ring halves, which ranges from about zero inches to about 0.010 inches. In some exemplary embodiments, the retainer and guide ring is formed by obtaining two identical rings and making a cut along an edge of the diameter on each ring thereby forming a larger ring arc and a smaller ring arc for each of the rings. The two larger ring arcs are used to form the retainer and guide ring. In another exemplary embodiment, the retainer and guide ring is formed by obtaining a single ring and making a cut along the diameter.

Abstract: A drilling apparatus includes a percussive member configured to generate impact waves, a striking bar configured to receive impact waves from the percussive member, a rotation section at least partly enclosing the striking bar, a flushing section detachably connected to the rotation section, and a vibration isolator attached to the flushing section. The rotation section includes a bearing configured to support the striking bar. Further, the flushing section includes an inlet passage configured to receive a flushing medium.

Abstract: A dust extraction device for a machine hand tool is provided. The dust extraction device includes an outer tube arranged about an axis, the outer tube being closed on the first axial end thereof by a wall. An opening is provided for a pump connection, the opening being arranged in a position neighboring the wall in a shell wall of the outer tube. An attachment feature is provided having a sheath-like shape and arranged on the side of the wall which lies opposite the outer tube in an axial extension of the outer tube. An inner tube is arranged inside the outer tube about the axis, and penetrates the wall. A length of the inner tube inside the outer tube is at least half of the length of the outer tube.

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 reversible, pneumatic ground piercing tool has a tail assembly with exhaust passages therethrough. At least a portion of each exhaust passage angles radially inwardly and ends in discharge ports that communicate with a central hole at the rear end of the tail assembly, whereby exhaust escapes through the central hole. A tail cone has a radially inwardly extending flange on the inner periphery of the central hole, which flange is rearwardly spaced from and covers the discharge ports.

Abstract: A dust collecting device for a handheld power tool equipped with a dust exhaust fitting (12), in particular for an electric handheld power sander, includes a dust collecting bag (14) that has an air-permeable filter bag (15) and a reinforcing plate (16). The reinforcing plate (16) is situated in front of the filter bag (15) and has an inlet opening (17) that fits onto the dust exhaust fitting (12). A support is attached to the handheld power tool and has a filter chamber (20) for insertion of the filter bag (15) and a receiving chamber (21) situated in front of the filter chamber (20) for insertion of the reinforcing plate (16).

Abstract: A filtration system for a gas powered concrete saw allows the user to inspect and/or determine how much dust is accumulated in the filter. In addition, manual filter cleaners are provided to allow the user to easily clean the filter without needing to open up the tool. In addition, the system is provided to deactivate the tool or notify the user if no filter is being utilized, or the filter is damaged. The system can also provide system lock out in the case of a missing or damaged filter. In addition, automatic methods are also provided to allow cleaning of the filter.

Abstract: A dust filter, in particular, for hand-guided power tools, includes a plate filter (18) with at least one spreader (14) for spreading filter folds (16) of the plate filter (18). The spreader (14) has a spreading device (24k 28), which is placed onto sides of the filter folds (16) of the plate filter (18) that are oriented away from a sealing frame (66) of the plate filter (18).

Abstract: A manually guided implement having a tool driven by an internal combustion engine, which draws combustion air in via an air filter disposed on an air filter base. The air filter is secured to the implement via a releasable securement device that includes a first securement element, and a second securement element that cooperates with the first securement element. The securement elements can be released from one another, or connected to one another, by means of a rotational movement about an axis of rotation. To achieve easy handling of the air filter, the first securement element is fixedly connected to the air filter.

Abstract: A dust collection container for power tool with suction capacity is described comprising a first pipe (15) for air inlet and at least one second pipe (20) for air outlet, i.e. connected to the external environment, the dust container (13) comprising a filtering element (22) placed inside an external casing (14). The container further comprising a bladed element (100) accommodated in the external casing (14) and being adapted to increase the air turbulence. The shape of the space comprised between the filtering element (22) and the external casing (14) determines a cyclonic type air motion.

Abstract: A rock drilling machine includes a sleeve having openings surrounding a portion of a lubrication channel. A groove surrounds the sleeve, and one end of a second channel is connected to the groove. The other end of the second channel is connected to a lubrication point so that lubricant from the lubrication channel is distributed from the lubrication channel, through the sleeve and groove to the second channel, and from the second channel to a lubrication point of the rock drilling machine.

Abstract: There is also provided a dust extraction module for use with a power tool, the dust extraction module having: a dust collection chamber (50) having an inlet (52) connectable in fluid communication with an outlet (44) of a dust-extracting duct (40) of the power tool, and having an outlet (54) in fluid communication with atmospheric air; and a filter (60) locatable in fluid flow between the outlet of the dust collection chamber and the atmospheric air; wherein the dust collection chamber (50) has a substantially circular cross section, the inlet (52) to the dust collection chamber is at the perimeter of the circle and the outlet (54) of the dust collection chamber is from the middle of the circle.

Abstract: An improved dust collector for a power tool is employed. The dust collector includes a body portion, a neck portion and a head portion, wherein the body portion is disposable on the power tool so that during the cutting operation the body portion will receive and direct the air, dust, and debris to the head portion via the neck portion to either be exhausted out or to be collected in a dust collection volume. Preferably, the body portion has a series of openings to allow the user to view the cutting wheel during the cutting operation. The body portion may also have an internal directional member for efficiently directing the flow of air, dust, and debris. The head portion is preferably rotatably connected to the neck portion to allow the user to rotate the head portion to a desired position.

Abstract: A drilling attachment for use in wet and dry drilling operations includes a housing having first and second fluid conduits, and a drive shaft mounted within the housing and having fluid transmitting first and second end portions in fluid communication with a respective first and second fluid conduit. In one embodiment, at any time one end of the drive shaft is coupled to a drive unit and the other end of the drive shaft is coupled to a core drill bit. In a dry drilling operation, dust is extracted from the core of the drill bit, is passed through the drive shaft and exits the housing via one of the fluid conduits. In a wet drilling operation, fluid such as water is passed through the other of the fluid conduits, through the drive shaft and into the core of the drill bit.

Abstract: The present invention refers to a motorized tool with suction and dust collection capacity. The tool comprises: means for extracting dust suitable for producing a flow of air; means for collecting dust having a first duct for the entrance of the air, that can be connected separately to said tool, and at least one second duct for the air, connected to the outside environment; said means for collecting dust include a filtering element positioned between said first duct and said second duct. Said filtering element defines an internal space and an external space surrounding said internal space, one of which is in communication with said first duct and the other is in communication with said second duct.

Abstract: A dust suppression guard includes a shroud defining an enclosed space. The guard also includes a clamp mounted adjacent a first end of the shroud, a reinforcing member attached to a central portion of the shroud, and a boot attached adjacent a second end of the shroud. The dust suppression guard also includes a hose mounted to and extending through the shroud in communication with the enclosed space. A dust suppression system may include a vacuum source having an attached vacuum hose, where the vacuum hose connects to the hose mounted to and extending through the shroud.

Abstract: A hydraulic percussion drill includes a piston hammer disposed in a cylinder for reciprocating movement in response to pressure fluid acting continuously on one transverse face of the piston hammer and in response to valving of pressure fluid alternately to an opposed piston face of the piston hammer by a tubular sleeve valve disposed around the piston hammer. The drill includes a percussion bit configured to have a face portion disposed at an acute angle with respect to a plane normal to the bit and the drill central axis. Cooperating spiral splines on the bit and a bit chuck provide for directional drilling using a method which includes causing the bit to receive impact blows without rotating the cylinder housing to initiate a deviated drillhole.

Abstract: An improved downhole fluid pressure powered reciprocating rotary drilling motor includes an automatic fluid valve means and a fluid controller that in combination provide a fluid driven periodic forcing function to excite a drill bit both axially and rotationally for enhanced drill bit penetration in oil well work-over and oil well open hole earth borings on both rotating and non-rotating drill strings.

Abstract: A hydraulic reciprocating piston hammer percussion drill includes an elongated piston hammer having opposed reduced diameter shank portions and disposed in a cylinder for reciprocating movement in response to pressure fluid acting continuously on one transverse face of the piston hammer and in response to valving of pressure fluid alternately to an opposed piston face of the piston hammer by a tubular sleeve valve which is disposed in sleeved relationship around the piston hammer between a piston portion of the piston hammer and an impact blow receiving bit. The tubular sleeve valve is provided with ports which communicate with high pressure and fluid exhaust ports in the piston hammer to effect reciprocation of the sleeve valve and of the piston hammer to deliver repeated impact blows to the bit.

Abstract: A hydraulic reciprocating piston hammer percussion drill includes an elongated piston hammer having opposed reduced diameter shank portions and disposed in a cylinder for reciprocating movement in response to pressure fluid acting continuously on one transverse face of the piston hammer and in response to valving of pressure fluid alternately to an opposed piston face of the piston hammer by a tubular sleeve valve which is disposed in sleeved relationship around the piston hammer between a piston portion of the piston hammer and an impact blow receiving bit. The tubular sleeve valve is provided with ports which communicate with high pressure and fluid exhaust ports in the piston hammer to effect reciprocation of the sleeve valve and of the piston hammer to deliver repeated impact blows to the bit.

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: A pneumatic downhole impact drill has a backhead for mounting an inlet check valve and a mounting hub for mounting a fluid delivery tube. A split ring has an interior circumferential groove forming upper and lower shoulders and comprises two substantially identical semi-circular ring segments. The ring segments are positioned around flanges on the backhead and the mounting hub such that the upper shoulder of the split ring slidably engages the upper surface of the backhead flange and the lower shoulder slidably engages the lower surface of the mounting hub flange to mount the backhead to the mounting hub. A first gap is formed between the outside surface of the split ring and the inside surface of the casing. A second gap is formed between the inside surface of the groove and the outside surfaces of the mounting hub and backhead flanges. Taken together, the gaps allow lateral relative movement between the mounting hub and backhead flanges.

Abstract: A pneumatic downhole impact drill has a porting system for automatically supplying pneumatic pressure fluid from a fluid delivery tube received within an axial bore in the impact piston to the opposite ends of the piston operating cylinder as the piston reciprocates. A flange on the delivery tube is slidably mounted in a cavity in a mounting hub assembly. Passageways provide fluid communication between the pressure fluid inlet plenum and the operating chamber side of the cavity and between the back chamber and the inlet plenum side of the cavity. Fluid pressure forces acting on the opposite faces of the flange and on the top end surface of the delivery tube reciprocate the delivery tube between upstroke and downstroke positions. Positioning the delivery tube in the upstroke position increases the axial distance that the piston must travel before the pressure fluid supply is connected to the back end of the operating chamber on the piston upstroke.

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 vacuum impregnated porous cylinder is utilized in a vane type air motor to provide a continuous source of lubrication for the vane tips rotating within the cylinder thereby eliminating the need for lubricant dispersion in the air supply.

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 system for lubricating and reciprocating a piston in a fluid-activated, percussive paving breaker includes a unitary valve assembly positioned within a bore of a rear portion of a tool housing, the valve assembly having an oil reservoir for lubricating the piston. The valve assembly is retained in place by a combination of a throttle lever and a backhead plate bolted to the rear tool housing.

Abstract: A system for lubricating and reciprocating a piston in a fluid-activated, percussive paving breaker includes a unitary valve assembly positioned within a bore of a rear portion of a tool housing, the valve assembly having an oil reservoir for lubricating the piston. The valve assembly is retained in place by a combination of a throttle lever and a backhead plate bolted to the rear tool housing.

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 system for lubricating and reciprocating a piston in a fluid-activated, percussive paving breaker includes a unitary valve assembly positioned within a bore of a rear portion of a tool housing, the valve assembly having an oil reservoir for lubricating the piston. The valve assembly is retained in place by a combination of a throttle lever and a backhead plate bolted to the rear tool housing.

Abstract: A powered machine for inserting an attachment member having a filament with a head at one end through an opening in an article and including a needle which is projected from machine in order to penetrate that article and convey the filament head therethrough, in which the needle is cleaned during each actuation thereof by being wiped and/or having a jet of fluid blown across it, and in which the machine is provided with structure for grasping a tag which is to be penetrated by the needle, holding the tag in position while the needle penetrates it, and permitting the release of the tag after the fastening operation has been completed, all with positiveness and facility of manipulation.

Abstract: A fluid distributor for a debris flushing system in a fluid-activated jackhammer includes a bore through a reciprocal piston, for fluid flow into an exhaust chamber, a fluid distributor removably mounted in the piston bore, the fluid distributor operating by forming passageways through the bore and blocking flow in other portions of the bore. The distributor can have a tapered body that can be severed along its length by the operator to provide a plurality of preselected, fixed flow rates.

Abstract: Improvements in down-hole mud actuated hammers are disclosed. According to its broadest aspect the invention is a down-hole mud actuated hammer for use in a drill string, which includes a housing with an upper end having means for connecting to the drill string. A throat is located within the housing which throat includes a main flow passage to allow high pressure drilling mud to pass therethrough. A piston is provided which is adapted to move axially within the housing means to thereby reciprocate between an up position and a down position. The piston is moved between the up and down position by a minor portion of the high pressure mud which portion passes from the main flow passage into at least one piston actuating chamber. This minor portion of mud is exhausted from the piston actuating chamber to a low pressure region out of the housing without being returned to the main flow passage.

Abstract: A throttle lever system for operating a flushing system on a percussive, fluid-activated apparatus includes a fluid inlet port, passageways in the apparatus for exhaust fluid, a seal device for opening and closing the passageways, and a throttle lever system for operating the seal device, the throttle lever system including a one-piece throttle lever elastically and pivotally mounted on a pivot pin on the device to cantilever out over the seal device, whereby the lever elastically moves up and down into and out of contact with the seal device, in response to operator hand pressure.

Abstract: A debris flushing system for a percussive, fluid-activated apparatus includes a first and second separate and independent flushing system in the apparatus, each flushing system having a separate combination of passageways in the apparatus for fluid communication between an inlet port and a front piston exhaust chamber. Each flushing system has a separate seal and throttle combination for opening and closing its own passageways. A third, independent flushing system for flushing water can be added to the apparatus.

Abstract: A throttle lever system for operating a flushing system on a percussive, fluid-activated apparatus includes a fluid inlet port, passageways in the apparatus for exhaust fluid, a seal device for opening and closing the passageways, and a throttle lever system for operating the seal device, the throttle lever system including a one-piece throttle lever elastically and pivotally mounted on a pivot pin on the device to cantilever out over the seal device, whereby the lever elastically moves up and down into and out of contact with the seal device, in response to operator hand pressure.

Abstract: Device in hammer machines. The device comprises a machine housing (1) and a hammer piston (2) movable to-and-fro in the machine housing. A drilling tool connected to the machine housing comprises a drill bit (5), a set of tubes (4) for rotating the drill bit and a set of rods (3) for transferring impact energy to the drill bit. A rod (11) situated adjacent to the drill bit is provided with an axial channel (7) and a radial channel (8) for supplying flushing medium to the flushing channel (6) of the drill bit. The distance (S) from the front end (9) of the drill bit to channel (8) is larger than the length (L) of the hammer piston (2).

Abstract: A downhole percussion drill or hammer (100) is disclosed having an outer casing (2) in which a reciprocating piston (26) which periodically impacts a drilling bit (16) disposed at a bottom end of the casing. A top chuck (1), attached to the top end of the casing, conducts pressurized air to the interior of the casing. A flow tube (5) includes a supply passage (27) and an exhaust passage (10). No cylinder sleeve exists between the inner diameter of the casing (2) and the outer diameter of the piston (26). Rather, the flow tube (5), piston (26) and interior structure of the casing cooperate to direct pressurized air alternately to the top and bottom ends of the piston while alternately opening and closing the exhaust passage. Accordingly, for a predetermined outer casing diameter, a relatively thicker casing wall and relatively larger top piston surface results in higher relative performance than prior hammers having a cylinder sleeve.