Abstract: An impact hammer for breaking a working surface, the hammer including a drive mechanism and a housing with an inner containment surface and a reciprocating hammer weight. A reciprocation cycle of the hammer weight includes an upstroke and a down-stroke, the hammer weight respectively moving upwards and downwards. On the down-stroke the hammer weight impacts a striker pin with a driven end and a working surface impact end. A vacuum chamber in the housing is formed by the containment surface, upper vacuum sealing coupled to the hammer weight and lower vacuum sealing. The hammer weight is driven toward the striker pin by the pressure differential between atmosphere and the vacuum chamber formed on the upstroke. A down-stroke vent permits fluid egress from the vacuum chamber on the down-stroke.

Abstract: The present invention relates to a hydraulic down-the-hole hammer. The hammer comprises an elongate shaft and a piston having a central bore therethrough, the piston slidably mounted for reciprocal movement on the shaft and arranged to impact a percussion bit. Forward and rear drive chambers for the piston are disposed between the piston and the shaft and the forward chamber is separated from the rear chamber by an annular shoulder formed internally of the piston bore. The hammer also comprises a control valve to control reciprocation of the piston, wherein the control valve is arranged within the central bore of the piston. The hammer may be a disposable water hammer in which the piston is an outermost component of the hammer.

Abstract: An impact hammer for breaking a working surface, the hammer including a drive mechanism and a housing with an inner containment surface and a reciprocating hammer weight. A reciprocation cycle of the hammer weight includes an upstroke and a down-stroke, the hammer weight respectively moving upwards and downwards. On the down-stroke the hammer weight impacts a striker pin with a driven end and a working surface impact end. A vacuum chamber in the housing is formed by the containment surface, upper vacuum sealing coupled to the hammer weight and lower vacuum sealing. The hammer weight is driven toward the striker pin by the pressure differential between atmosphere and the vacuum chamber formed on the upstroke. A down-stroke vent permits fluid egress from the vacuum chamber on the down-stroke.

Abstract: A down the hole rock drilling machine and a method of drilling rock. The drilling machine comprises a casing (15) inside which is a control sleeve (20). A reciprocating piston (19) is arranged to move inside the control sleeve and control feeding and discharging of working chambers (20, 21). Between the control sleeve and an inner surface of the casing are all the fluid passages (28, 29, 30, 31) needed for fluid routing. The piston opens and closes transverse openings and controls the work cycle.

Abstract: A down the hole rock drilling machine and a method of drilling rock. The drilling machine includes a reciprocating piston, which has a sleeve-like configuration. Inside a central opening of the piston is arranged one or more fluid passages for conveying pressurized fluid during the work cycle of an impact device of the drill machine.

Abstract: An impact hammer (1) for breaking a working surface (5), the hammer including a drive mechanism (11, 12, 14) and a housing (6) with an inner containment surface (8) and a reciprocating hammer weight (9). A reciprocation cycle of the hammer weight (9) includes an upstroke and a down-stroke, the hammer weight (9) respectively moving upwards and downwards. On the down-stroke the hammer weight (9) impacts a striker pin (4) with a driven end (17) and a working surface impact end (18). A vacuum chamber (22) in the housing is formed by the containment surface (8), upper vacuum sealing (24) coupled to the hammer weight (9) and lower vacuum sealing (25). The hammer weight (9) is driven toward the striker pin (4) by the pressure differential between atmosphere and the vacuum chamber (22) formed on the upstroke. A down-stroke vent (43) permits fluid egress from the vacuum chamber (22) on the down-stroke.

Abstract: A leveling device assembly for use with a hydraulic hammer is provided. The leveling device assembly comprises a control unit, a leveling sensor in communication with the control unit, and a laser generator in communication with the control unit. Additionally, the laser generator is configured to produce a first colored light beam and a second colored light beam different from the first colored light beam. The control unit is further configured to cause the laser generator to produce the first colored light beam when the leveling sensor indicates the hydraulic hammer is in a substantially vertical position and produce the second colored light beam when the leveling sensor indicates the hydraulic hammer is in a substantially non-vertical position.

Abstract: Provided is a stepless variable auto stroke hydraulic breaker system capable of reducing impact energy reflected in the event of an idle blow by detecting a frequency of vibrations generated when a chisel breaks objects such as bedrocks using a vibration sensor, operating according to a short stroke if the frequency of vibrations does not exceed a preset frequency, and automatically switching the short stroke into a long stroke if the frequency of vibrations exceeds the preset frequency. The breaker system includes a vibration sensor configured to detect vibrations generated when a chisel breaks rocks, a transmitter provided with the vibration sensor and configured to transmit signals generated from the vibration sensor, a receiver configured to receive the signals transmitted from the transmitter, and a stepless variable auto stroke hydraulic breaker controlled by a reception micro controller unit (MCU) of the receiver.

Abstract: The absorber for a hand machine tool according to the invention with a linear drive has a case and a body of mass moveable alongside of an absorber axis relative to the case. Force is applied toward a first direction to a first coupling element moveable alongside of the absorber axis, which is coupled with the body of mass using a first spring. Force is applied toward a second direction to a second coupling element moveable alongside of the absorber axis using a second spring coupled with the case. With a movement toward the first direction, the first coupling element is frictionally coupled with the second coupling element and with a movement toward the second direction, it is uncoupled from the second coupling element.

Abstract: The invention relates to a ram boring device for creating horizontal boreholes, having an impact piston which moves in an oscillatory manner within a casing of the ram boring device and of which the impact frequency or impact intensity can be varied by displacing the center position of the impact piston inside the casing.

Abstract: A ball valve assembly for use as a control valve for controlling the flow of gas through a continuous stroke pneumatic tool. The valving element is generally spherical and non-magnetizable. The generally spherical valving element is loosely confined between two concave generally conical surfaces, which are provided on valve seat members. The concave generally conical surfaces are opposed to one another to define a valve chamber therebetween. Sufficient clearance is provided so the generally spherical valving element is free to roll and tumble as it moves in the valve chamber between the concave generally conical surfaces. This allows the ball valve assembly to be self purging of excess lubricant, dust, and the like. Wear is distributed over the entire generally spherical surface of the valving element. The loose confinement is also sufficient to provide a relatively large cross-section of gas passageway through the control valve assembly.

Abstract: A method and means of minimizing the effect of elastic valve recoil in impact applications, such as percussive drilling, where sliding spool valves used inside the percussive device are subject to poor positioning control due to elastic recoil effects experienced when the valve impacts a stroke limiting surface. The improved valve design reduces the reflected velocity of the valve by using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact.

Abstract: A pneumatic device control apparatus and method comprising a ported valve slidably fitted over a feed tube of the pneumatic device, and using a compliant biasing device to constrain motion of the valve to provide asymmetric timing for extended pressurization of a power chamber and reduced pressurization of a return chamber of the pneumatic device. The pneumatic device can be a pneumatic hammer drill.

Abstract: A fluid distributor cylinder is for a percussive drill assembly that includes a casing having an inner circumferential surface defining a central bore, a central axis extending through the bore, a bit movably coupled with the casing and a piston movably disposed within the casing bore. The distributor cylinder includes a generally tubular body disposeable within the casing bore and having first and second ends, a central axis extending generally between the first and second ends, an outer circumferential surface. At least a section of the outer surface is configured to engage with the inner surface of the casing so to form an interference fit between the body and the casing. The cylinder includes an exterior thread and/or a radially-extending shoulder configured to releasably engage with the casing inner surface so as to substantially prevent axial displacement of the distributor body with respect to the casing.

Abstract: Pressure-air driven percussion device for a down-the-hole drill with a hammer-piston which is axially reciprocally movable in a hammer-piston chamber through a driving device. The hammer-piston in operation acting with a hammer-end against an upper end of a drill bit which is positioned inside a chuck. An air-cushion for reducing percussive power is arranged to be formed at the hammer-end of the hammer-piston in positions where the drill bit has been moved past a predetermined distance in the percussion direction. The drill bit is sealingly slidingly supported in a drill bit bushing, and the hammer-end of the hammer-piston is formed so that it sealingly cooperates with the drill bit bushing in the positions in order to form the air-cushion.

Abstract: A pneumatic impact tool and method includes a cylinder pipe or housing closed with a cover, as well as an impact piston that forms a first pressure chamber between an impact plate and the impact piston, and a second pressure chamber between the cover and the impact piston. The cover is provided with at least one opening, the surface of which is smaller than the piston surface, whereby the impact piston seals the opening when it is in its fully retracted position.

Abstract: A percussion adapter for a positive displacement motor including a housing, a torque tube and a reciprocating percussive piston operable by application of fluid pressure thereto. The piston can be driven to create a percussive effect by rotary movement of the torque tube. The percussion adapter can have a bypass option to allow flow through the percussion adapter without operation of the piston.

Abstract: A pneumatic hammer comprises an elongate hollow casing with operatively upper and lower ends and has a piston slidingly received within the casing and operable to reciprocate within the casing between upper and lower pressure chambers defined within the casing. The hammer further has an axially displaceable bit assembly at the lower end of the casing and a backend assembly at the upper end of the casing. The piston has a striking face at an end thereof proximate the bit assembly, and the piston is operable to impact on a contact surface of the bit assembly in an impact region of the casing. The hammer is characterized in that the piston is shaped and dimensioned at its proximal end to have a snug sliding fit with an interior of the casing in the impact region of the casing.

Abstract: The invention relates to a percussive tool having an oscillatory drive (3), the force of which is transmitted to a tool bit holder (25) by way of a drive member (17). Extending through the percussive tool is a longitudinal opening that allows a rod-shaped object, such as, for example, a guide wire, to be guided through the percussive tool. The tool bit holder (25) has a seat (34), which can receive the tool bit in different orientations. Moreover, the tool bit holder (25) is made of a combination of light metal and steel, which allows a reduction in acceleration forces and noise generation.

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: A sleeve carried by and preferably slidable relative to the piston, for controlling air passages associated with a central air feed tube, whereby retraction pressure is applied to the piston substantially at impact. It is the impact itself of the piston against the bit, which enhances sliding of the sleeve relative to the piston, over the feed tube, and thereby switches the airflow at the moment of impact.

Abstract: The invention relates to a ground working implement and to a method for introducing a working element into the ground, using vibrations. By means of a vibration generator vibrations are generated and transmitted to the working element during its introduction into the ground. According to the invention a gentle vibration generation and transmission are brought about in that the vibration generator has at least one vibrating piston mounted in linearly displaceable manner in a casing spaced from the working element. The vibrating piston is driven in oscillating manner in the casing for generating vibrations. The vibrations are transmitted via the casing to the working element.

Abstract: A down-the-hole hammer includes a casing and a piston movable in the casing between a lowermost operating position and an uppermost operating position. A recess is provided between the piston and the casing so that the piston and the casing define an intermediate chamber between a top end of the piston and a bottom end of the piston. A passageway is provided between a source of pressurized fluid and the intermediate chamber such that, at all positions of the piston between the lowermost and the uppermost operating positions, the source of pressurized fluid is in flow communication with the intermediate chamber through the passageway. An opening in the piston at least partially defines the passageway.

Abstract: A pressure-fluid driven device for generating a reciprocating movement includes a first (5) and a second relatively movable part (3), wherein a working chamber (7) is intended to be alternatively pressurised and depressurised so as to drive the parts in a movement relative to each other when the working chamber is pressurised. A valve arrangement (8) is intended to control the fluid flow into as well as from the working chamber. The inlet into the working chamber (7) is separate from the discharge from the working chamber (7). The invention also concerns a valve arrangement and a pneumatic tool.

Abstract: The lower end portion of a pneumatic impact hammer cylinder has at least one upper fluid passage and at least one lower fluid passage. A U-shaped sleeve is mounted in a circumferential groove in the lower end portion of the piston. The sleeve includes a base, upper and lower legs extending radially outward from the base, and a cavity extending axially between the legs. The sleeve has an axial length that is less than the axial length of the piston groove such that the sleeve is slidably movable within the piston groove between an upstroke position and a downstroke position. The upper fluid passage and the lower fluid passage cooperate with the sleeve cavity, as the piston reciprocates between the impact position and the recovery position, to supply pressure fluid to the impact end of the operating chamber for a portion of each upstroke and each downstroke.

Abstract: An air hammer includes an air hammering mechanism and a vibration suppressing device to absorb the vibration transmitted from the air hammering mechanism. The vibration suppressing device includes a cylinder forming a front channel and a rear channel in communication with each other. First and second air passageways are defined in the cylinder and in communication with the front and rear channels respectively. A valve is movably received in the front channel. The valve defines a bore and third air passageways selectively alignable with the first air passageways. A piston is movably received in the rear channel and forms a projection. A jacket surrounds the cylinder to form therebetween an air chamber that communicates the second air passageways. The jacket has a closed end defining a hole into which the projection is selectively received to block the hole.

Abstract: A fluid channeling device is for a percussive drill including a casing having an interior space, drive and valve chambers defined within the interior space, a piston disposed within the casing and having an upper end disposeable within the drive chamber and a longitudinal through-bore, and a valve for controlling flow into the drive chamber. The device includes a first member partially disposed within the drive chamber so as to extend into the piston bore when the piston end is within the drive chamber. The first member has an outer surface, an interior space and one or more ports extending between the outer surface and interior space and fluidly connectable with the drive chamber. A second member is disposed within the first member interior and has a passage fluidly connected with the valve chamber and fluidly connectable with the port(s) to establish fluid communication between the drive and valve chambers.

Abstract: There is provided drilling apparatus (10) comprising a hammer casing (11), a free piston motor piston guide and porting sleeve (12), a drive sub (13), a drill bit (15) splined by shank (16) to the drive sub (13). Below the splined portion (17) the drive sub is relieved at (23) to form an annular air space for motor exhaust air from the splines (16) and (17). The drive sub (13) retains a gauge sleeve (24) via an annular flange (25) between the hammer casing (11) at (26) and a shoulder (27) on the drive sub (13). Below the shoulder (27) the outer diameter of the drive sub (13) is provided with eight grooves that form conduits (30) with the lower portion (31) of the gauge sleeve (24) extending parallel to the drill axis in communication with the space (23) via ports (32). The lower portion (31) extends down the side of the drive sub (13) and terminates with it at (34) adjacent the shoulder (33) at the transition from the bit shank (16) and the bit head (35).

Abstract: A percussive rotational impact hammer assembly for creating high torques. A generally cylindrical piston rotatably mounted on a hammer inside an outer casing oscillates on the hammer and strikes an impact surface on the hammer. The piston and housing have pressurized fluid ports and passageways for conducting pressurized fluid to alternately load an impact-driving chamber and return chamber. The piston is accelerated against the impact surface and the kinetic energy of the piston is transmitted to the hammer transmitting the rotational movement to a member engaged with the hammer, such as a drill bit or other member. The rotational impact hammer assembly can be adapted for use in a downhole hammer, in break out tongs for drill pipe, in wrenches for loosening or tightening nuts and bolts, or in other mechanical devices where high torque is desired.

Abstract: An impact hammer system for driving an elongate member comprising a ram member, a frame assembly, an actuator assembly, and a power source. The ram member defines a ram bore. The frame assembly supports the ram member such that the ram member may move relative to the frame assembly between first and second positions. The actuator assembly is operatively connected between the frame assembly and the ram member and is operable in extended and retracted configurations. At least a portion of the actuator assembly is disposed within the ram bore and a substantial portion of the actuator assembly extends out of the ram bore when the cylinder is in the extended position. The power source is operatively connected to the actuator assembly to place the actuator assembly in the extended and retracted configurations. Extension and retraction of the actuator assembly moves the ram member between the first and second positions, respectively.

Abstract: A fluid-operated percussion device (1) having a percussive piston (3), which alternately executes a work stroke and a return stroke due to the effect of a control. To avoid no-load strikes, in one embodiment of the percussion device (1), the percussive piston (3) is shut down if it has overshot the extended position occurring in normal operation (long- and/or short-stroke operation) by a predetermined distance in the work-stroke direction (arrow 3e) and reached a no-load-strike position. For this purpose, the interior (2d) of the work cylinder (2) that receives the percussive piston (3) additionally has a no load-strike opening (20a), which is connected to the pressure line (8) of the percussion device (1) with an interposed safety element (21) that can be switched between an inoperative position and an operative position.

Abstract: A down-the-hole percussive drill comprises a casing, a drill bit mounted at a lower end of the casing, a hollow feed tube fixed within the casing and extending along a center axis thereof, and a piston mounted for axial reciprocation within the casing for transmitting impacts to the drill bit. The upper portion forms a downwardly facing surface at the junction between the upper and lower portions. Passages for conducting lubricant-containing pressurized air are formed in the piston. At least one of those passages constitutes a vertical recess formed in the outer periphery of the piston. The piston includes a radially outwardly projecting rib disposed between upper and lower ends of the recess. Air is blocked from traveling past the rib until the rib becomes located opposite an annular groove formed in an inner surface of the casing.

Abstract: A down-the-hole percussive drill comprises a casing, a drill bit mounted at a lower end of the casing, a hollow feed tube fixed within the casing and extending along a center axis thereof, and a piston mounted for axial reciprocation within the casing for transmitting impacts to the drill bit. The piston has a stepped configuration in that a lower portion thereof is of smaller outer diameter than an upper portion thereof. The upper portion forms a downwardly facing surface at the junction between the upper and lower portions. Air-conducting passages are formed in the upper portion of the piston and are supplied with pressurized air from the hollow feed tube. One of those passages intersects the downwardly facing surface of the upper portion of the piston. The hollow feed tube is mounted to a top sub of the drill by pins which are mounted in the top sub and extend radially into a sidewall of the feed tube, the pins being situated outside of the central passage.

Abstract: An in-hole hammer for boring in ground has an elongated hollow housing carrying an internal striking piston in a piston chamber. An exchangeable boring head is threadably connected to the forward end of the housing and the striking piston impacts against the forward wall of the housing defining the piston chamber to transmit forward driving impact energy to the boring head. A boring rod which urges the hammer forwardly and rotates it about the longitudinal axis is connected to the rear end of the housing through a connecting piece non-rotatably fixed, but slidable relative, to the housing so that the axially directed impact energy produced by the striking piston is not transmitted to the boring rod.

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: An improved fluid actuated percussive impact tool of the valveless type adapted for down hole drilling is provided. The impact tool includes a casing, a back head, a distributor located at a first end of the casing, and an impact receiving device located at a second end of the casing. A chamber is located between the distributor and the impact receiving device. A cylinder sleeve is located in the chamber adjacent to the distributor. A first pressurized fluid passage is located between the casing and the cylinder sleeve for passing pressurized fluid from the distributor to the chamber. A piston is located in the chamber for reciprocating axial movement. Axially extending ports are located on at least one of the piston, the cylinder sleeve and the casing in the chamber for alternately supplying pressurized fluid to upper and lower chamber portions.

Abstract: The striking element (1) according to the invention serves for the production of shocks which act on a tool. It has a body (3) with a plurality of parallel bores (4). A piston (2), heavy in mass, runs pressure-tight in each of these bores (4) and strikes stops which may be mounted without or within the piston (2). An end space (9) lies at each of the faces of the piston (2). The pistons (2) serve to control the function of the striking element (1). At least one of the pistons (2) produces shocks on the tool. The striking element may execute working shocks in the direction of the tool and, in a special embodiment, execute loosening shocks in the opposite direction. In a special embodiment the magnitude of the energy of loosening shocks may be adjusted or suppressed.The striking element is employed principally in surgery, but also in the general manufacture of apparatus.

Abstract: A hydraulically operated rock drill including a cylinder, a piston mounted for reciprocating movement in the cylinder, a hydraulic fluid line connected to the cylinder, and an accumulator. A chamber with a section of reduced dimensions is formed in the cylinder, and the piston includes an annular formation which moves within the chamber and into and out of the section as the piston reciprocates. The accumulator is connected via a port to the section, and the hydraulic fluid line is connected to the chamber and is in communication with the accumulator when the annular formation is out of the section and which is cut off from the accumulator, by the annular formation, when the annular formation moves into the section, the annular formation then pressurizing hydraulic fluid in the section whereby hydraulic energy, produced by kinetic energy developed over at least part of a return stroke of the piston, is stored in the accumulator. A second accumulator is connected at least to the high pressure line.

Abstract: A fluid-operated striker assembly includes a working cylinder and a striker piston slidably received in the working cylinder for executing working (forward) and return strokes. The striker piston delivers a blow to a tool bit during the working stroke when the striker piston is either in a limit position or in an advanced position which is beyond the limit position in the direction of the working stroke. A control arrangement applies an alternating fluid pressure to the striker piston to execute the working and return strokes. Further, a precontrol arrangement is provided for affecting the control arrangement dependent on whether the striker piston has exceeded its limit position.

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

Abstract: A kind storing energy type of impact control mechanism for pneumatic wrench comprises a flying hammer and a centrifugal valve fitted in the flying hammer, a timing mechanism, a spring, a retaining ring, a limiting device composed of a limiting key-slot on the centrifugal valve and a limiting plunger head with one end sticking into the centrifugal valve chamber and an impact pin. Besides, there are a stretching air duct to make the impact pin stretch and a transition air duct, and a retracting air duct to make the impact pin retract. And on the outer periphery of the centrifugal valve there are a concentric annular slot and an eccentric slot communicating with each other, and another concentric annular spaced apart from them. The above-mentioned structure can raise the controlled air pressure in pneumatic wrench, lower machining difficulty and reduce flying hammer height.

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

Abstract: A unitary valve assembly for a fluid-activated, percussive paving breaker includes a valve chest having an outer sidewall forming an internal valve chamber, a sidewall within the internal chamber forming a valve bore, a reciprocal valve within the valve bore and a bottom plate permanently fastened to the outer sidewall. The inner sidewall forms a first annular, upstanding sealing seat for the valve, and the bottom plate forms a second annular, upstanding sealing seat for the valve. Passageways through the valve assembly are positioned so as to connect with high and low pressure chambers of a paving breaker, when the valve assembly is inserted into the paving breaker. For weight reduction, the valve assembly is made of acetal resin.

Abstract: A vibration dampened percussive tool has a handle assembly and a cover surrounding a barrel and piston assembly which are caused to oscillate relatively to the handle assembly. The barrel assembly receives a tool retainer and a trigger controls primary air supply. To reduce air consumption when the tool is not actually applied to a workpiece and thereby to reduce exposure of the operator's hand/arm to vibration, an air metering device is provided, which includes a tube slidably mounted in a bush and having a bleed hole in an end of the tube which enters the bush. In one position of the tube within the bush, apertures in the tube are sealed to allow the tool idle and in another position of the tube the apertures are exposed. The tube connects the air line with the piston assembly and moves within the bush responsive to pressure applied by the actual tool on the workpiece.

Abstract: A pneumatic tool includes: a main cylinder having an operating lever for on-off control for the supply of compressed air into the pneumatic tool, a barrel member resiliently coupled to the main cylinder and having a tool unit secured at its front end portion, and an automatically closed throttle valve held in the main cylinder, whereby upon touching on a working object when starting the pounding job, the barrel member will be retracted to open the throttle valve for performing the pneumatic operation by the pneumatic tool; and when subjected to no load condition, the throttle valve will be restored and closed automatically to temporarily stop the pounding of the pneumatic tool to minimize vibration hazard, and an air cushion is inherently formed between the barrel member and the main cylinder for dampening or absorbing the vibration shock of the pneumatic tool.

Abstract: A hydraulic device for driving piles including a casing accommodating a striker with an anvil block, a hydraulic power cylinder, having a rod connected to the striker and a hydraulic directional control selector. A control unit is separated from the directional control selector and is secured on a housing of the power cylinder coaxially with the striker. The hydraulic directional control selector comprises two valves, each of which is provided with two pilot chambers, communication pairwise with each other. The first valve puts the head end of the power cylinder in communication with the rod end, and the second valve establishes communication between the head end and the return flow line.

Abstract: A tool for removing a metal plug from a tube with repeated pulling impulses includes a pneumatic cylinder defining an interior, cylindrical chamber. A distal end surface of the cylinder defines an anvil. A cylindrical slug, or hammer, is sealingly slidable within the chamber in response to a pressure difference above and below the hammer within the chamber. The cylinder is rigidly connected to the plug so as to hang therefrom, the weight of the cylinder providing a static pull force working in conjunction with the pulling impulses. A pulling impulse is provided by first raising the hammer above the anvil by pneumatically creating a first pressure difference wherein the pressure below the hammer is greater than the pressure above the hammer, then creating a second pressure difference wherein the pressure below the hammer is no greater than the pressure above the hammer in order to drive the hammer against the anvil at speed.

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

Abstract: 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.