Abstract: A method for adjusting the impact force on a hammer operated by a compressible pressure medium utilizes a hammer including a working cylinder having a to-and-fro moving percussion piston and a spindle positioned therein for striking a tool. The working cylinder is positioned inside an outer shell and the spindle is attached to the outer shell. The working cylinder is movable relative to the outer shell and the spindle. A pressure chamber is formed between the working cylinder and the outer shell and pressure medium is fed into or removed from the chamber to adjust the position of the working cylinder relative to the outer shell. In making this adjustment, the strength and frequency of impact of the piston against the opposite end of the spindle is adjusted.

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: Apparatus comprising a striking piston driven hydraulically in a reciprocating fashion by an incompressible fluid inside a cylinder and striking against a tool, of the type in which the piston slides in a cylinder having two concentric piston bearing surfaces of different sections, of which that situated on the tool side has a section smaller than that remote from the tool, the piston and the cylinder delimiting two antagonistic chambers, an annular bottom chamber and a top chamber of larger section.According to the invention the interior of the top chamber is permanently at a regulated pressure of a value intermediate between the inlet or high pressure and the outlet or low pressure, and the annular bottom chamber is connected alternately by a distributor to the high pressure supply circuit during the upward phase of the piston and to the top chamber during the accelerated downward phase of the piston.

Abstract: A pneumatic hammer is provided with an adjusting piston (37) dependent on the supply pressure, which adjusts the stroke length of the working piston (16). Thereby, the same pneumatic hammer may be operated both at low and high supply pressures. With high supply pressures, either the early ending of the acceleration phase or the early start of the compression phase or the shortening of the working cylinder shortens the stroke length. Thereby, the pneumatic hammer performs impacts with a substantially constant single-impact energy, regardless of the supply pressure. High supply pressures increase the impact frequency. This results in a considerably improved efficiency at a high drill capacity, a reduced wear and a reduced risk of ruptures of the components of the hammer.

Abstract: A reversible casing for a down-the-hole drill has a predetermined snap ring groove length centered between the casing ends, based upon the casing bore, the snap ring groove depth and the snap ring body length, whereby a snap ring will be retained in the snap ring groove, while permitting lengthwise movement of the snap ring during reverse orientation of the casing.

Abstract: The invention is a pneumatic impact hammer in which the vibrations created in the motor portion of the tool are substantially reduced prior to reaching the tool's handle portion. The motor portion is allowed to move relative to the tool's handle portion and is located within a handle-attached cylindrical housing. Low-friction plastic bearings are located between the motor portion and the surrounding housing. The cycling valve that controls the reciprocating movement of the tool's piston is attached to the motor and receives air from a flexible air inlet tube that is slidably engaged to the motor and is secured to the tool's handle portion.

Abstract: A valveless percussive pneumatic drill includes a housing, a piston in the housing, reciprocating along the axis of the housing, a piston support bearing in the housing and an air distributor in the housing, the air distributor being mounted in the housing for flexible elastic movement therein, to permit slight misalignment of the piston with respect to the axis of the housing.

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.

Abstract: A percussion drilling apparatus having an outer casing, a fluted inner sleeve affixed to the outer casing, a hammer piston having a longitudinal opening therethrough adapted to fit around extensions of a cyclic valve positioned at the top of the inner casing, and a foot valve mounted atop a drilling bit at the bottom of the apparatus. An air channel positioned between the inner sleeve and outer casing is adapted to cooperate with channels on a reciprocating hammer piston to alternately drive the hammer piston up and down.

Abstract: A valveless percussive pneumatic drill includes a housing, a piston in the housing, reciprocating along the axis of the housing, a piston support bearing in the housing and an air distributor in the housing, the air distributor being mounted in the housing for flexible elastic movement therein, to permit slight misalignment of the piston with respect to the axis of the housing.

Abstract: In accordance with the present invention there is provided a pneumatic slide hammer for removing a plug from a tube or other structure including a percussive piston, a housing for containing the percussive piston and for connecting to the plug to be removed from a structure, and a slidable cylindrical valve for controlling the flow of air under superatmospheric pressure to force the percussive piston against to impact against the housing and force the plug from the housing.

Abstract: A pneumatic downhole impact drill having a porting system for automatically supplying pneumatic pressure fluid from a fluid delivery tube received within a coaxial bore in the impact piston to the opposite ends of the piston operating cylinder as the piston reciprocates. The porting system comprises an annular set of equiangularly spaced outlet ports in the fluid delivery tube and two sets of radially extending bores in the piston having first and second, axially spaced, annular sets of equiangularly spaced inlet ports which cooperate with the outlet ports in the delivery tube. The number of inlet ports in the piston in each set thereof, is different than the number of outlet ports in the supply tube and the combined angular widths of the ports of each set of inlet ports and the outlet ports is substantially greater than 360.degree. to provide substantial fluid communication therebetween at all relative angular positions of the piston and fluid delivery tube.

Abstract: A pneumatic impacting mechanism comprising a first cylinder and a piston with a rear air distributing bar and a front air distributing bar which simultaneously acts as an impacting head of the same, said rear distributing bar having an axially extending air inlet channel, which in turn can be connected, through a radial air channel in the piston, alternatively with a pair of air inlet channels leading to a second cylinder of a plunger valve, said plunger valve being provided with two annular grooves at both ends for alternatively controlling two air inlet channels and two air exhaust channels. In this manner, the quantities of compressed air entering into the first cylinder during forward and backward strokes are determined by the lengths of the two distributing bars. Moreover, two air buffer chambers are provided at both ends of the first cylinder so that the compressed air doing work within said first cylinder can expand to approximately atmosphere.

Abstract: A piston is oscillating periodically within a cylinder, propelled by compressed air. At at least one of its end positions, the piston generates a stroke that acts on a working tool, e.g. a rasp. The sizes of the piston surfaces acted upon by the compressed air and the capacities at the cylinder volumes limited by the piston are dimensioned such that the impact momentum of the piston at both end positions is essentially the same. In case of a bone rasp working tool this equal momentum of the stroke advancing the rasp into the bone and the stroke loosening the tool by retracting it, leads to an optimum working of the bone and as little stress as possible on the patient.

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.

Abstract: Replacing valves in prior percussive devices, the distributor is a simple tube, which can be of plastic construction, for admitting operative compressed air to drive and return chambers at opposite ends of the centrally-bored hammer piston. The tube-distributor effects a fine, substantially sealing, relatively slidable clearance with the hammer piston bore. The housing is a simple, uniform bore diameter cylinder in which the hammer piston reciprocates; tight-concentricity tolerance machining of the confronting inside and outside diameters of the cylindrical housing, distributor and hammer piston, respectively, is unnecesssary.

Abstract: An impact borer is disclosed for embedding lines and for sinking geothermal wells. The impact borer has a shell, which has a longitudinal bore. An anvil closes one end of the bore. A ram is reciprocally slideable within the bore, against and away from the anvil. The ram divides the bore into front, rear, and ram chambers. A director is joined to the shell. The director is monolithic. The director isolates the front and rear chambers in alternation upon reciprocation of the ram. The director defines an inlet passage communicating with the ram chamber and an outlet passage communicating with the rear chamber.

Abstract: An impact tool includes a body, a barrel mounted on the body and a cylinder disposed within the barrel and reciprocally moved by a drive mechanism. A communication groove is formed between the cylinder and the barrel and communicates with the outside. The cylinder includes a plurality of communication holes formed in a radial direction and spaced from each other in a longitudinal direction. A striker is reciprocally movable within the cylinder, and an air chamber is formed between the striker and the cylinder. The striker is positioned at a first position when the tool bit is not pressed on a work. The striker at the first position permits communication between the air chamber and the communication groove through any one of the communication holes so as to be prevented from idle impact. Further, the striker is movable to a second position rearward of the first position through the pressing operation of the tool bit on the work.

Abstract: An apparatus with two limit positions and generating a reciprocating motion, comprises a first moving part (4a, 4b) and a second moving part (16a, 16b) between which parts (4a, 4b; 16a, 16b) a pressurized drive medium (38a, 38b) such as compressed air, is disposed to simultaneously displace the moving parts (4a, 4b; 16a, 16b) in mutually opposite directions. At least the first moving part (4a, 4b) is actuated, by a constantly present force, for example by the pressure of the driving media (38a, 38b) applied on at least one surface of the first moving part (4a, 4b), in the forward direction under tensioning of an associated force accumulator (20a), for example a spring.

Abstract: The invention is concerned with pneumatic percussion drilling equipment with advantageous manufacturing simplicity and effective piston area to casing size consisting essentially of an elongate hollow casing housing a piston assembly and having a backhead at one end with a compressed fluid inlet, a bit assembly with a compressed fluid exhaust at the other end, and the backhead including a seal for a backhead end of the piston reciprocatable within the casing, the piston having axial bores extending inwardly from each end, inclined passages extending away from the inner ends of the axial bores to open through the wall of the piston at positions axially displaced from each other and towards opposite ends of the piston from their respective axial bores, and the casing walls having axially spaced apart recesses, the backhead seal, casing recesses and opening through the wall of the piston being such as to allow fluid under pressure introduced axially into the casing through the backhead, to reciprocate and to mai

Abstract: Described is a pneumatic knocking device for knocking dust off bunker walls, comprising a housing (1) which encloses an elongate spring chamber (13) with spring (9), having a vent bore (7), and which is closed at one end by a top wall (20) with hole (10), a valve wall (3) with connecting hole (8), a piston (2) which is movable towards the top wall (20) by means of compressed air against the pressure of the spring (9), and a quick-acting vent valve (3, 8, 10, 11, 14a, 15) which is disposed in the region of the valve wall (3) and which vents the chamber (22) beneath the piston (2) into the spring chamber (13) by means of an air conduit (14).

Abstract: A pneumatic percussion tool for rock breaking and other purposes having removably enclosed within an outer casing a pneumatic engine including a cylinder with a work head extending slidably from its lower end, a piston slidable in the cylinder impacting the work head on its downstroke. The piston serves also as a sliding valve into which compressed air is admitted through an air inlet tube fixed coaxially in the cylinder and on which the piston is slidable. The piston and cylinder are formed with such air ports and passages that the engine remains at rest until the work head applied with pressure to a work-piece is retracted into the cylinder displacing the piston valve which thereupon is reciprocated, causing the work head to deliver percussive blows while applied to the work-piece. At the final part of its upstroke, the piston enters a compression chamber or energy cell which thus decelerates the piston and commences its downstroke.

Abstract: A pneumatic percussion hammer casing (10), a top sub (23) connected to the outer tube of a double tube drill stem, an air feed pipe (19) extending from the top sub (23) co-axially into the casing and co-axially about an air outflow pipe (21) connected at its upper end to the inner drill stem tube, its lower end slidable in an air passage (38) through bit (31) the shank of which (32) is slidable in a driver sub (33) at the lower casing end and topped by an anvil (35), a passage (43) having ducts (39,44) extending to the exterior of the bit (31). A tubular piston (27), slidable in the casing (10) co-axially about the air outflow pipe (21) engages, when brought down onto the anvil (35), tube (37) rising from passage (38) through the bit, shank and anvil. Annular chambers (11, 12, 13) are formed within the casing (10) and the axial passage of the piston is divided into upper and lower passages (29,30).

Abstract: A fluid impact tool is disclosed of the type commonly known as a down-the-hole drill for drilling of rock. The improvement herein described increases deep hole drill performance by providing a means for accumulating piston return air in a traveling air pocket found on the piston. This effectively increases the piston front end volume so as to decrease the effect of the front end air cushion and thereby increase impact. This is particularly effective during operation with increased back pressure such as found in deep holes.

Abstract: An improved fluid actuated rock drill hammer as shown having a cylinder housing, a reciprocal piston, and a centralized air distributing control tube axially extending through a central bore in the piston for controlling the operation of the piston. The control tube is mounted for assured concentricity of the tube within the piston bore and comprises a unitary mounting portion and tubular portion. The mounting portion includes a piloting section for concentric fit within the cylinder as received on a shoulder therein and the tubular portion extends concentric and perpendicular to the piloted section.

Abstract: A valveless down-the-hole hammer drill is actuated by fluid such as compressed air. The drill includes a piston disposed within a chamber defined within an outer wear sleeve, an air diverter at one end and a suspendably mounted drill bit at the other end, wherein the piston has a slidable contact surface with the chamber towards each end of the piston, such that the piston is slidably reciprocable within the chamber. Porting and exhaust arrangements alternately supply and exhaust live pressure fluid to either end surface of the piston to reciprocate it and cause it to repeatedly strike the drill bit. An intermediate compression chamber is defined between the two sliding contact surfaces of the piston between the piston and the outer wear sleeve. Air trapped in the intermediate chamber is compressed so as to apply a retarding force on the piston towards the end of the return stroke, and to provide additional impetus to the piston on the commencement of the drive stroke.

Abstract: A valveless pneumatic hammer comprising a backhead assembly at one end of a hollow casing and a bit assembly at the other end of the casing, a rod extending into the casing and having a passage out to atmosphere at the other end of the assembly, a chamber divider in the backhead end of the casing having a control rod projecting into the casing, a piston having a large bore in one end and a smaller bore end and the larger bore end being adapted to cooperate with the chamber divider end for the sealing of the larger bore, the piston reciprocating between a first position with the smaller bore end against the bit assembly, and a second position with the piston displaced towards the backhead assembly, a first chamber with the piston in the first position, a second chamber with the piston in the second position, first and second fluid supply paths through the backhead assembly, between chamber divider walls and the casing wall, first and second fluid exhaust paths from the first and second chambers, respectively o

Abstract: A percussion tool has a frame in which a percussion element is fitted such that it can move axially by a small distance and in which a hammer for hitting the percussion element is supported axially movably. The hammer is moved toward a standby position by a supply of a high pressure thereto, while forming a negative pressure acting on the hammer to force it toward a percussion position and, in the standby position, the high pressure is released to allow the hammer to move toward the percussion position by the negative pressure.

Abstract: A pneumatic percussion machine has chambers at its ends with air inlet and exhaust passages thereto, controlled by a piston reciprocable between the chambers, an air supply passage from an axially adjacent end chamber to a third chamber being opened only after the air supply to the other end chamber is closed off.

Abstract: In deep bore drilling it is usual to use a fluid operated percussive hammer to provide necessary drive for the boring operation. However a difficulty which is encountered with hammers which are currently in use is that the manufacture of the components for such hammers involves considerable amount of precise machining which not only increases the manufacturing cost of such units but also reduces the service life of the components. Some of the typical hammers in use generally comprise an outer cylindrical casing with a feed tube positioned concentrically within the casing and a piston slidably mounted within the casing and over the feed tube to reciprocate therein and impact on a drill bit mounted in and retained at the bottom of the casing.

Abstract: A fluid operated hammer comprising; a casing; a top sub mounted to one end of the casing; a drill bit mounted to the other end of the casing; a feed tube located concentrically within the casing and extending for a portion of the length of the casing from said one end; and a piston slidably mounted in the casing for longitudinal movement between the top sub and drill bit over the feed tube; the feed tube being formed with at least one elongate aperture wherein the longitudinal dimensions of the at least one aperture correspond to a significant proportion of the degree of reciprocation of the piston; a first passageway provided in the piston and extending between the central bore and the external face thereof to provide a communication between the at least one aperture and the space between the piston and the top sub when the piston is at or near the top sub and for a significant proportion of the degree of movement of the piston from the top sub to a drive the piston towards the other end of the casing; a reb

Abstract: A pneumatic downhole impact drill having a porting system for automatically and sequentially supplying pneumatic pressure fluid from a fluid delivery tube received within a central coaxial bore in an impact piston to the opposite ends of the piston operating cylinder as the piston reciprocates and for selectively and automatically connecting the non-impact end of the cylinder to exhaust via the coaxial bore in the piston as the piston reciprocates. The porting system provides two separate paths for supplying pneumatic pressure fluid to the non-impact end of the cylinder and employs annular porting grooves and internal drilled porting bores in only the non-impact end of the piston to minimize stress concentration from piston impact.

Abstract: Hydraulic breaking down or demolishing rock drill in which there is a stroke only pressing the drill against the surface to be broken down or drilled. The result is a reduced hard work of the operator and a reduced wear of the drill parts. This drill has an axial chamber body made of different cylindrical sectors, in which is sliding a rammer having two cylindrical joint elements of different diameter: the upper having a groove while the lower has an annular band-like piston ring. An intermediate sector of the axial chamber is equipped with a distributing valve for the oil, controlling the various working phases. The drill body is equipped with various oil pipes joining the oil tank with the sectors of the axial chamber, or such sectors altogether. The drill is also equipped with a device regulating the impact frequency.

Abstract: A fluid operated rock drill hammer includes an annular hammer body with the upper end of the hammer body adapted to be connected to a drill string and with a drill chuck mounted at the lower end of the hammer body. A drill bit extends through the drill chuck into the body. A piston is slidably mounted in the hammer body to move between the drill bit and the upper end of the hammer body for striking the portion of the drill bit that extends through the drill chuck. The force for moving the piston is provided by a fluid that is circulated through the drill string into the hammer body. A restricted exhaust port is provided for preventing back hammering of the piston by maintaining a high fluid pressure in the space between the piston and the upper end of the hammer body when the bit is off bottom.

Abstract: The device described contains a pneumatically operated hammer, a feeder controlling the flow of pneumatic fluid, an anvil which is struck repeatedly by the hammer, a drill bit attached to or integral with the lower end of the anvil, and an outer casing. The device is typically used as a down hole tool in rotary drilling operations and normally utilizes pressurized air as its pneumatic fluid. The pneumatic fluid first lifts the hammer above the anvil and second pushes the hammer downward to impact against the anvil in a striking movement. Simultaneous with striking, the pneumatic fluid above the hammer is expelled through an exhauster retained in the anvil and out through the drill bit where it is utilized to transport the cuttings from the hole being drilled. The feeder operates in conjunction with the hammer to control pressurization above and below the hammer, while exhaust above the hammer is controlled by the lower end of said feeder tube.

Abstract: A fluid operated rock drill hammer includes an annular hammer body with the upper end of the hammer body adapted to be connected to a drill string and with a drill chuck mounted at the lower end of the hammer body. A drill bit extends through the drill chuck into the body. A piston is slidably mounted in the hammer body to move axially between the drill bit and the upper end of the hammer body for striking the portion of the drill bit that extends through the drill chuck. The force for moving the piston is provided by a circulating fluid that is transmitted through the drill string into the hammer body. All of the fluid is transmitted between the hammer body and the piston at a single fixed axial position along the length of the hammer body.

Abstract: A pneumatic system includes a pneumatic motor, which may take the form of a vibrationless paving breaker utilizing a blow-striking member or hammer that is propelled to and from its force-transmitting or blow-striking position by a compressed gas. A valving arrangement provides for relatively large-ratio expansion of the compressed gas in the space under the hammer between its infeed thereinto and its exhaustion therefrom, in order to significantly utilize heat energy in the compressed gas to assist in energizing the propulsion of the hammer. Such heat energy is usually invested in the compressed gas by and during substantially adiabatic compression thereof at a gas-volume transformer, or compressor, included in the pneumatic system. It may be noted that the process of substantially adiabatic compression in the compressor is to a significant degree reversely duplicated in energizing the propulsion of the hammer.

Abstract: A hydraulic percussion or an impact apparatus for driving rock-breaking tools, drill bits and ramming or tamping tools comprises a body in which an end of the tool is received and a reciprocating mass formed as a piston which is axially displaceable in a cylinder. The cylinder is provided with a distributor member slidable above the piston and of the same diameter as the latter, the distributor being formed as a sleeve having a central portion engaging a collar of a plunger which extends into a piston and forms therewith a suction chamber. The plunger has an extension which is slidable in a bore of the body and is acted upon by the high-pressure fluid.

Abstract: A down-the-hole pneumatic drill in which the reciprocating hammer-piston slides over a ported tubular structure mounted centrally in the cylinder of the drill body and providing two longitudinal passages through which passes all the pressure air required below the piston. The tubular structure comprises an outer tube having a close-fitting inner tube within it, the inner tube being formed in its wall with a longitudinal indentation closed at the lower end, one of the passages being defined by the indentation and the wall of the outer tube and the other passage being defined by the interior of the inner tube. The tubular structure is provided with ports controlled by the sliding hammer-piston, certain of these ports being formed by registering holes in portions of the walls of the inner and outer tubes which lie in contact with one another.

Abstract: A hand held impact tool is disclosed which employs an impact piston reciprocated by means of fluid pressure to impact a working tool. Fluid pressure is continually supplied to a pressure chamber forwardly of the impact piston such that a fluid cushion is established between the forward end of the piston and a piston stop surface resulting in substantial noise reduction. The working tool is biased outwardly of the tool housing by fluid pressure such that the working tool must be placed against an external object and moved axially inwardly to effect impact with the piston, whereby accidental ejection or unintentional operating movement of the working tool is prevented.

Abstract: A percussion bit for use with a down-the-hole drilling motor having a hammer which reciprocates in the motor to impact on the upper end of the bit. The bit has a working position in the motor and an idle advanced position. When the bit is in the idle advanced position, the hammer advances to an idle position and, at that time, it is desired for the hammer merely to rest on the bit without impacting the bit. The hammer is reciprocated by fluid pressure and, according to the present invention, a bypass channel is formed directly in the bit which exhausts one of the pressure chambers for the hammer when the bit is in its advanced position.

Abstract: A fluid actuated impact tool is disclosed of the type commonly known as a down-the-hole drill for drilling of rock. The tool is provided with a reversible casing which serves the dual functions of a casing and cylinder. A partial cylinder sleeve is utilized in conjunction with exhaust rod porting to provide a drill which is simple in construction, has a high energy level of output, and eliminates the need for expensive cross porting or axial porting in the parts most subject to wear; that is, the impact piston and the casing. All of the porting in the casing is accomplished by means of circumferential grooves which are readily machined.

Abstract: A down-the-hole hammer of the type adapted for receiving a bit at the lower end and for being connected to the lower end of a drill string through which compressed air is supplied to the hammer. The supply of air to the hammer when the bit at the lower end is resting on the bottom of the hole causes a piston in the hammer to reciprocate and to beat upon the upper end of the bit so that the material at the bottom of a hole is reduced. The piston, by reciprocating in the hammer, accomplishes the valving of the fluid which causes the piston to reciprocate, and when the hammer is lifted from the bottom of the hole and the bit moves downwardly, the piston ceases reciprocation while air blows off through the bit to the bottom thereof to clear debris from the hole being drilled.

Abstract: An airhammer embodies an outer housing structure connectible to a rotatable drill pipe string through which compressed air is conducted. A hammer piston reciprocates in the housing structure, compressed air being directed alternately to the upper and lower ends of the piston to effect its reciprocation in the structure, each downward stroke inflicting an impact blow upon the anvil portion of an anvil bit extending upwardly within the lower portion of the housing structure. Upon elevating the airhammer off the bottom of the bore hole being drilled, the anvil bit drops downwardly of the housing structure to open one or more air bleeding grooves in the anvil bit, compressed air in the housing structure bleeding quickly through such grooves and preventing or stopping the hammer piston from reciprocating and impacting against the anvil bit.

Abstract: A pneumatic percussion machine such as a drill, having a piston reciprocating in a casing, chambers formed in casing at or towards the ends of the piston, the arrangement permitting compressed air to be supplied alternatively to the chambers, the compressed air to the one chamber being supplied through a projecting member located co-axially in the casing and over which the piston reciprocates and compressed air from the other chamber being exhausted through the projecting member to the other chamber.

Abstract: An air hammer embodying an outer housing structure connectible to a rotatable drill pipe string through which compressed air is conducted. A hammer piston reciprocates in the housing structure along flexible inlet and outlet tubes, compressed air being directed alternately to the upper and lower ends of the piston to effect its reciprocation in the structure, each downward stroke inflicting an impact blow upon the anvil portion of an anvil bit extending upwardly within the lower portion of the housing structure. The piston contacts the housing structure at the upper and lower portions of the piston only, so that the piston can deviate upon flexing of the housing structure under load, and not bind in the housing structure, as permitted by the flexible inlet and outlet tubes.

Abstract: An air hammer embodying an outer housing structure connectable to a rotatable drill pipe string through which compressed air is conducted. A hammer piston reciprocates in the housing structure, compressed air being directed alternately to the upper and lower ends of the piston to effect its reciprocation in the structure, each downward stroke inflicting an impact blow upon the anvil portion of an anvil bit extending upwardly within the lower portion of the housing structure. The compressed air acts against the piston over the full internal cross-sectional area of the housing structure in delivering its impact blow, such compressed air acting downwardly over at least a portion of the piston area during its entire downward stroke, including its latter portion, during which the power or impacting air is being exhausted from the housing structure.