Abstract: A system and method of fabricating a percussion tool that includes one or more surfaces modified using the ferritic nitrocarburization process. The percussion tool includes a piston positioned in sliding contact within a casing. The piston includes an inner wall and an outer wall, where the inner wall defines a passageway extending longitudinally therethrough. The outer wall is positioned in close fitting relationship with an internal surface of the casing. One or more surfaces of at least one of the casing's internal surface and/or the piston's outer wall are modified using the ferritic nitrocarburization process.

Abstract: Earth-boring tools may include a body and a passively adjustable, aggressiveness-modifying member secured to the body. The passively adjustable, aggressiveness-modifying member may be movable between a first position in which the earth-boring tool exhibits a first aggressiveness and a second position in which the earth-boring tool exhibits a second, different aggressiveness responsive to forces acting on the passively adjustable, aggressiveness-modifying member.

Abstract: A system and method of fabricating a percussion tool that includes one or more coatings applied onto a piston, casing, and/or flow tube. The percussion tool includes a piston positioned in sliding contact within a casing. The piston includes an inner wall and an outer wall, where the inner wall defines a passageway extending longitudinally therethrough. The outer wall is positioned in close fitting relationship with an internal surface of the casing. One or more coatings are disposed on at least one of the casing's internal surface and/or the piston's outer wall. A flow tube may be placed through the passageway such that an outer wall of the flow tube is in a close fitting relationship with the piston's inner wall. One or more coatings can be disposed on at least one of the piston's inner wall and/or the flow tube's outer wall.

Abstract: A hydraulic pick has a supporting body with a piston and a piston rod fixedly positioned in the supporting body. A working tool is driven by a short, axially rigid striking pin, guided in a bushing. A pressure transformer cylinder and an equalizing chamber are formed between the piston rod and a pressure transformer piston. The striking pin is driven by a working fluid under pressure, which is distributed by a system of channels in the piston rod.

Abstract: A pile driving system for driving a pile. The pile driving system comprises a housing assembly, a hammer, a helmet member, and a lifting system. The housing assembly defines at least one vent opening is arranged at a first vent location along the drive axis, and at least one vent opening is arranged at a second vent location along the drive axis. When the hammer drops and is above the first vent location, ambient air flows from the main chamber through the vent openings formed at the first and second vent locations. When the hammer is below the first vent location and above the second vent location, ambient air flows from the main chamber through the vent openings formed at the second vent location. When the hammer is below the second vent location, air within the main chamber is compressed to preload the helmet member.

Abstract: A percussion device has a machine housing (1), a forwards and backwards movable percussion piston (2) in the machine housing, and a reciprocatingly movable valve body (6) in the machine housing. The percussion piston has a first (4) and a second (5) driving surface subjected to pressure to drive the percussion piston (2) forwards and backwards. The valve body (6) has a first end surface (12) and a second end surface (13) for driving the valve body in first and second directions by applied pressure. The valve body (6) is arranged over a channel (7) in the machine housing, to connect at least the second (5) driving surface alternately to a pressure source (8) or to low pressure (9), and the second end surface (13) is alternately connectable by the percussion piston (2) to the pressure source (8) or, over a valve device (11) for creating a counter-pressure, to the low pressure (8).

Abstract: Hammering apparatus functioning with a pressurized medium, such as a pressure fluid of a hydraulic system which hammering apparatus comprises an elongated body (19) to be attached to a power tool, a movable impact mass (10) adjusted to rest on the body (19) for which impact mass a linear control part is adjusted to the mentioned body (19) and an arrangement for lifting up the movable mass (10) for the impact comprising the first cylinder (20) and a piston (16) which can be moved in it with the help of pressure fluid and a piston rod (1) in which case in the arrangement the mentioned piston rod (1) is attached to the mentioned mass (10) and comprises a valve arrangement (15) with the help of which the pressure of the hydraulic fluid can be directed to the first cylinder (20) to the other side of the piston (16) for the uplifting of the mass (10) and the mentioned pressure can be suddenly reduced when the mass (10) is being directed to impact.

Abstract: A fluid powered percussion tool 1 has a housing 2 with a supply channel for pressurized fluid 3, a percussion mechanism 4, a swing joint 5 arranged to carry the percussion mechanism 4 relative to the housing 2 at a point situated between the forward end A and the rear end B of the percussion mechanism 4, at least one elastically resilient element 6 arranged between the housing 2 and the percussion mechanism 4 at a distance from the swinging joint 5 and arranged to load the percussion mechanism 4 against a neutral position in the housing 2 and to absorb the vibrational movements of the percussion mechanism 4, and a flexible connection for pressurized fluid 7 for distribution of pressurized fluid from the supply channel for pressurized fluid 3 to the percussion mechanism 4. The elastically resilient element 6 includes a conical spring 8. The flexible connection for pressurized fluid 7 includes a hose 11.

Abstract: According to the invention, the body of the apparatus includes a flow rate adjustment device including a calibrated opening provided on a high-pressure fluid supply circuit, a bore formed in the body and in which is mounted a slider having a first face located in a first chamber connected to a high-pressure fluid supply circuit upstream from the calibrated opening and a second face located in a second chamber connected to the high-pressure fluid supply circuit downstream from the calibrated opening, the bore receiving the slide including an annular groove connected to a low pressure feedback circuit. The slider is adapted for connecting the annular groove to the first chamber when the pressure difference on either side of the calibrated opening increases beyond a predetermined value in order to divert a portion of the fluid flow supplied by the high-pressure fluid supply circuit to the feedback circuit.

Abstract: A pressure fluid operated impact device comprising a frame (2) whereto a tool (3) is mountable movably in its longitudinal direction, and control means (7) for controlling pressure fluid feed to the impact device (1), as well as a method of generating a stress pulse in a pressure fluid operated impact device. The impact device (1) comprises a working chamber (8) and a transmission piston (9) moving therein. Energy charging means for charging energy of pressure fluid and the control means are coupled to allow periodically alternately pressure fluid to flow to the working chamber (8) and, correspondingly, to discharge pressure fluid from the working chamber (8). In the method, pressure fluid is fed to the working chamber (8), which produces a force pushing the transmission piston (9) in the direction of the tool (3), thus generating a stress pulse in the tool (3).

Abstract: A percussive device and method having, inside a machine housing (3), a reciprocally moveable percussive piston (2), the movement of which is controlled by a control valve (5), which is arranged to alternatively connect a chamber to a pressure source and to low pressure in dependence on a signal corresponding to the axial position of the percussive piston, and a valve (16) arranged to allow adjustment of the axial position of the percussive piston at which the signal is transmitted, by opening and blocking of a connection between one or more control channels (10, 11, 12, 13) and the control valve.

Abstract: A device for driving various objects using combustible fuel. Embodiments are contemplated in which the driver could be a post-driver, a power shovel, a jack-hammer or other devices. Typically, the device includes a body with a combustion chamber. A fuel injection valve selectively supplies fuel to the combustion chamber where it can be ignited using an ignition module. A piston is movable within the body to impact the ram responsive to combustion in the combustion chamber.

Abstract: A pressure-fluid-operated percussion device includes a frame allowing a tool to be arranged movably in its longitudinal direction. Pressure liquid is fed to the percussion device and returned to a pressure liquid tank. A stress pulse is produced in the tool utilizing pressure of the pressure liquid. A pressure liquid source maintains pressure in the working pressure chamber. Pressure liquid is intermittently fed to the percussion device such that the pressure liquid pushes a transmission piston into a predetermined backward position. Pressure liquid is alternately discharged rapidly from the percussion device so that the pressure of the pressure liquid in the working pressure chamber and the pressure liquid flowing from the pressure liquid source pushes the transmission piston towards the tool, generating a stress pulse in the tool.

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

Abstract: According to the invention, the body of the apparatus includes a flow rate adjustment device including a calibrated opening provided on a high-pressure fluid supply circuit, a bore formed in the body and in which is mounted a slider having a first face located in a first chamber connected to a high-pressure fluid supply circuit upstream from the calibrated opening and a second face located in a second chamber connected to the high-pressure fluid supply circuit downstream from the calibrated opening, the bore receiving the slide including an annular groove connected to a low pressure feedback circuit. The slider is adapted for connecting the annular groove to the first chamber when the pressure difference on either side of the calibrated opening increases beyond a predetermined value in order to divert a portion of the fluid flow supplied by the high-pressure fluid supply circuit to the feedback circuit.

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: An impact hammer drill capable of performing drilling operation at a high speed with low noise and without requiring a large thrust. The drill includes a main shaft rotatable by an output shaft of a motor, and a spindle having an impact-receiving section and disposed over the main shaft slidably in its axial direction and rotatable together with the rotation of the main shaft. A piston is reciprocatingly slidably disposed over the main shaft for impacting against the impact-receiving section. A piston drive unit is disposed for driving the piston with a compressed fluid. A compressed fluid supplying unit is disposed for supplying the compressed fluid to the piston drive unit. A drill bit is attachable to the spindle. When performing drilling operation, the drill bit is imparted with a combined rotational motion and the reciprocal impact motion.

Abstract: A power tool (1) having a striking means (5), by which a percussive tool (2) that can be driven at least partially along an axis (A) struck directly and having a flushing bore (4) extending at least partially longitudinally through a tool shank (3), and having a flushing head (6) having a radially inwardly open transverse bore hole (8) connected in a flow-through fashion with a fluid channel (7). The flushing head (6) has at least one hollow cylindrical sleeve-like guide surface (9), which is fitted for an insertion end (10) of the striking tool (2). The striking means (5) sealed by a seal (11a, 11b) is cup-like. The striking means (5) is moveably guided and made fluid tight by the seal (11a, 11b) to embrace the machine-side part of the insertion end (10) having the machine-side open flushing bore (4).

Abstract: An impact tool has a slidable hammer that is driven by hydraulic oil under pressure inside a chamber. The hydraulic oil is pressurized by a piston driven by compressed gas on the opposite side of the piston from the hydraulic oil. The gas in the gas chamber is compressed by the piston on an initial stroke, and has a large annular chamber holding the gas so that higher average gas pressure can be attained during the power stroke. As the piston is moved to compress the gas, the piston lifts a valve that opens a passage for the hydraulic oil moved by the piston to act on a hammer to impact a breaking tool. The piston is a two part piston that serves to lower the inertia during the final closing of the valve, and thereby reduces impact loads on the valve as it is closed. The valve also is controlled as to its stroke for efficient operation.

Abstract: A multi-purpose hydraulic tool of the open center and closed center type is provided with an OC/CC knob mounted on the trigger activated spool. The spool has a knob which can be turned to easily move between OC and CC operating conditions, without the use of additional tools. A check spool assembly works in conjunction with spool assembly in the open-center condition to provide for release of oil at the end of the return stroke. Adapters are provided so that crimping heads can be easily interchanged.

Abstract: The present invention discloses, in certain aspects, systems and methods for producing cyclical impacts and, in certain aspects for moving a drilling apparatus for drilling a borehole in a formation, the system in certain embodiments including a housing with a longitudinal axis and a movable member movably disposed therein and movable within the housing transversely to the longitudinal axis of the housing and positioned within the housing with a first space on a first side thereof and a second space on a second side thereof, the movable member substantially fluidly isolating the two spaces and movable to compress gas in one of the first space and the second space while decompressing gas in the other space so that a charge of compressed gas exits from the housing to move an impact member; e.g. for impacting a pile to be driven into the earth or for impacting a drill apparatus for drilling a wellbore, the movable member movable continuously to provide a series of impacts.

Abstract: The invention comprises a staple gun with highly compact accessory apparatus for attaching a planar tab or label to a fixing surface. The accessory has a housing and a positioning and indexing assembly associated with the housing which is operable to feed and hold a tab or label between the staple gun head and fixing surface, thereby allowing single-handed fixing of a label or tab to a fixing surface. The apparatus can include a roller assembly, staple gun and accessory apparatus or have all components integrated into the construction of a staple gun apparatus. Preferably, the apparatus is mated with a tab or label holding magazine. Some exemplary embodiments of the invention are suitable for securing protective covering to lumber product and may be configured for rectangular polyolefin tabs measuring approximately 0.035 inch thick and 1.0 inches by 2.0 inches.

Abstract: In the hydraulic tool, a main body section includes a cylinder and a piston. A head section is attached to the cylinder, includes a movable part. The piston is capable of rotating about the cylinder with the movable part. A control section is provided to the cylinder and includes oil paths and a switching valve. A piston valve reciprocally moves to control communication between a first and a second cylinder chambers. A concave is provided in a bottom face of the cylinder, escapes an end of the piston valve from a position at which the end of the piston valve contacts a bottom face, and shuts off the communication between the chambers. A projection is provided at a position different from the concave, makes the end of the piston valve contact the bottom face and allows the communication between the chambers.

Abstract: A power feed apparatus for applying a thrust force to an output shaft of a motor driven tool to drive the output shaft linearly towards and away from a workpiece without applying off-axis forces to the output shaft that would cause it to move out of perfect perpendicular alignment to the outer surface of the workpiece. The apparatus includes a first tubular member which is fixedly secured to a jig or other like mounting structure associated with the workpiece. A second tubular member is disposed for sliding linear movement along the first tubular member. Spaced apart annular fluid chambers are formed within the apparatus along with associated fluid ports for allowing a pressurized fluid to be used to both extend and retract the output shaft of the tool. The tool itself is supported on the second tubular member and thus moves linearly along with the second tubular member.

Abstract: A method and a device for determining the operating time and the operating condition of a hydraulic percussion unit, in particular a hydraulic hammer, having a percussion piston which is guided inside a housing and, under the effect of a controller, alternately performs an operating stroke in an impact direction and a return stroke in a return direction. The method and device obtain information to determine whether the percussion unit requires maintenance operations. Signals are generated during the consecutive, individual operational segments of the percussion unit. The number of signals is proportional to the strokes performed by the percussion piston in one movement direction. The number of the signals is continuously added and is stored as a total number. The current total number of signals can be displayed at least at times for indicating the operating condition of the percussion unit.

Abstract: A motor housing (11) is mounted in a handle body (10) so as to slide in the longitudinal direction. A tubular pipe (37) that can slide in a bore (38) of the body (10) projects from the back of the housing (11). Compressed air can be applied to the bore (38) through a switching valve (40). A piston (14) with a piston rod (17) can slide in the housing and a tool can be secured to its front end. A flutter valve (23) which alternatingly connects the bore (38) to the two cylinder chambers (27, 28) is built into the valve housing (22). The piston (14) alternatingly opens the connection to an outgoing air conduit (29-31). A pre-stressed spring (47) is set between the body (10) and the housing (11). In operation, the housing (11) oscillates out of step with the piston (14), so that their initial forces are largely compensated and no vibrations are transmitted to the handle body (10).

Abstract: A hammer device has a machine housing (1) with a hammer piston (2) movable to-and-fro. The to-and-fro movement of the hammer piston is controlled by a valve body (6) movable to-and-fro in the machine housing. The valve body, via a channel (7), alternatively connects a drive surface (5) on the hammer piston to a pressure source (8) and to low pressure (9). In order to expedite the actuation of the hammer piston at its rear dead center, the machine housing has a room (10) which is separated from the channel (7) by the hammer piston at the same time that the valve body (6) maintains the pressure from the pressure source (8) on the rear end surface (5) of the hammer piston.

Abstract: A hand drill including a housing (2), a rotary drive (8-15) arranged in the housing (2) for driving a chuck (6) provided at a front, in the drilling direction, end of the housing and in which a drill or a chisel tool is received, a compressed air-operated hammer mechanism having a pneumatic cylinder (22), a die member (15) for imparting axial blows to the drill or chisel tool, and a percussion piston (30) displaceable in the pneumatic cylinder 922) upon being impinged by compressed air for intermittently applying axial blows to the die member (15), and a reversing valve for connecting the hammer mechanism (22) with a source of compressed air, integrated in the percussion piston (30), and having a plurality of recesses and bores (46-52) alternatively operationally connectable with at least one inlet opening (23) and at least one discharge opening (24) of the pneumatic cylinder (22) for feeding the compressed air into the pneumatic cylinder (22) and for discharging the compressed air therefrom.

Abstract: When cutting metal rods, for instance, percussion machines are used that utilize stored kinetic energy which has been produced either mechanically or by the use of compressed gas. A drawback is the inability to accurately control the cutting process. The present invention makes use of hydraulics to control the process, thereby achieving total control of the course of the function.

Abstract: A hydraulic hammer having an improved seal ring contacting with a piston. The hydraulic hammer having a cylinder having an inner surface where a fluid groove connected to a passage for passing the fluid is formed, a piston installed in the cylinder to be elevated, and a first seal ring for guiding the elevation of the piston, installed in an inner surface of the cylinder under the fluid groove and contacting with the piston, includes one or more second seal rings having one or more grooves or holes for passing the fluid, installed on the fluid groove and/or between the fluid groove and the first seal ring. Accordingly, the length of use before replacement of the seal ring installed between the piston and the cylinder can be extended, to thereby reduce the cost for operating the hydraulic hammer.

Abstract: The invention relates to a hydraulically operated impact device, such as a percussion hammer or some other breaking apparatus, comprising a control valve (6) for controlling pressure fluid supplied to and from the percussion piston (1) so that the direction of motion of the piston (1) can be changed in accordance with the cycle of operation of the impact device. According to the inventive idea, when the control valve (6) is in the impact position, the impact device is provided with a closed space that is partly bordered by the control valve and the percussion piston. The percussion piston (1) comprises a section which communicates with said space and which has a larger diameter than the upper end of the piston. The control valve and the percussion piston are thus able to move in the same direction until a connection is opened from this closed space to the upper end of the percussion piston (1).

Abstract: A fluid-powered percussion tool includes a percussion piston which, under the effect of a control alternately performs a working stroke and a return stroke with the aid of a control valve. The control valve assumes a working stroke or a return stroke position, depending on the position of the percussion piston. In the working stroke position, the percussion piston is admitted with working pressure such that it performs a working stroke counter to the effect of a continuous reset force. In contrast, the percussion piston is connected in the return stroke position to a discharge line so that it performs a return stroke under the effect of the reset force. The control valve is admitted during the working stroke with working pressure and is thereby held in the working stroke position.

Abstract: A hammer assembly which decreases the severity of impact shocks generated by the hammer assembly during operation thereof is disclosed. The hammer assembly includes a housing defining a chamber. The housing further defines an injector port and an exhaust port each being in fluid communication with the chamber. The hammer assembly further includes a work tool positioned in the chamber, a piston positioned within the chamber, a first hydraulic pressure source which moves the piston in a work stroke toward the work tool, a second hydraulic pressure source which moves the piston in a return stroke away from the work tool, and a damping fluid source in fluid communication with the injector port. The hammer assembly still further includes a first valve which allows damping fluid to be advanced from the damping fluid source and into the chamber during the work stroke, and prevents damping fluid from being advanced from the damping fluid source and into the chamber during the return stroke.

Abstract: Hydraulic percussion hammer, in which a motion of a percussion piston (1) is controlled by a main valve (3), the control motion of which is controlled by a separate control valve (9) in such a way that the main valve changes its state, when the pressure acting on the control valve (9) rises to a predetermined value. The percussion hammer comprises a controller (21) mounted in its return duct (13), by which controller an outflow of pressure fluid from the percussion hammer can be adjusted in such a way that the filling rate of a pressure accumulator (7) and thus the length of a return motion of the percussion piston (1) are proportional to the flow resistance provided by the controller (21).

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: 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 hydraulic ram assembly is provided to be used, singly or in multiples, in raising a weighted member, such as a hammer (30) for pile driving, each having means whereby fluid used to extend a respective piston (26) can readily escape to give a sudden release, gravity induced return movement.

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 hydraulically operated striking mechanism includes a contact pressure control member held at least temporarily in contact with an insertion end of a drilling tool by a mechanism which applies a restoring force in the striking direction. A control conduit is connected by way of the contact pressure control member either to a pressure conduit or to a pressure return conduit. The control conduit actuates a switching element so that a control unit which alternatingly switches the movement of the striking piston performs a reversal movement into an operating stroke position at an earlier or later point in time during the return stroke of the striking piston and thus actuates the operating stroke of the striking piston in the striking direction.

Abstract: A valveless-type down-the-hole hammer drill which has an inner tube extending from the upper end of the hammer body into a central opening in a cutter bit reciprocably mounted in a chuck on the opposite end of the hammer body. High pressure fluid is supplied to the interior of the inner tube and a piston surrounding the inner tube has internal surfaces controlling connection of a port to chambers above and below the piston. The external surface of the piston controls connection of these chambers to an exhaust port. A valve sleeve on the chuck coacts with the piston in this respect.

Abstract: A fluid-powered hammer drill has a bore in which a tool shaft is normally coaxially engaged. A piston displaceable in the bore defines a front return chamber of small effective piston surface area and a rear drive chamber of larger effective surface area. A passage permanently connects the front chamber with the high-pressure side of a pressure source. A reversible control valve is connected between both sides of the source and the rear chamber for alternately pressurizing and depressurizing same and thereby alternately displacing the piston axial forward to strike the rear end of the tool shaft and axially backward. A recoil-damping sleeve surrounds the piston axially ahead of the front chamber and has a front end axially forwardly engageable with the tool shaft in a frontmost position and a rear end defining with the bore a recoil chamber separate from the front return chamber. The housing is formed with a vent passage connected to the low-pressure side of the source and opening into the recoil chamber.

Abstract: An apparatus for inserting fasteners which are press fit through aligned apertures in side-by-side workpieces. The apparatus includes a frame which is moveable relative to the side-by-side workpieces, the frame including a main frame and a subframe mounted on the main frame and moveable between the first and second positions. The subframe carries tooling in the form of a drill and an upper ram. Also, mounted on the main frame are upper and lower spaced apart clamps which may be selectively moved into contact with upper and lower surfaces of upper and lower workpieces. The upper ram can be moved into contact with a headed fastener to force the shank of the fastener through aligned apertures drilled in the workpieces. A vibrating apparatus is associated with the upper ram and will be operated to hammer the upper ram while it is still being maintained in contact with the fastener after the fastener has been inserted into the workpieces to fully insert the fastener and relieve any stresses which may be present.

Abstract: A valveless-type down-the-hole hammer drill which has an inner tube extending from the upper end of the hammer body into a central opening in a cutter bit reciprocably mounted in a chuck on the opposite end of the hammer body. High pressure fluid is supplied to the interior of the inner tube and a piston surrounding the inner tube has internal surfaces controlling connection of a port to chambers above and below the piston. The external surface of the piston controls connection of these chambers to an exhaust port. A valve sleeve on the chuck coacts with the piston in this respect.

Abstract: A pressure-medium driven percussion device including a body, a drill shank gliding axially in the body for transmitting percussions to a drill rod and a percussion piston moving in the body for directing percussions axially to the drill shank. The drill shank includes a lifting piston which moves in a lifting cylinder within the body. The body further includes a channel passing to the lifting cylinder for supplying and removing pressure medium into and out of the lifting cylinder and seals located between the body and the drill shank at both sides of the lifting cylinder. An equalizing channel is located between each seal and a corresponding choking slot. A valve connects the equalizing channels to the source of pressure medium when a channel passing to lifting cylinder is connected to a pressure medium container, and, correspondingly, to the pressure medium container when the channel passing to the lifting cylinder is connected to the source of pressure.

Abstract: Improvement to a hydraulic striking machine including among other things a body part and a piston, moving to and fro in the body and being accelerated to strike against a tool. The air current produced is led out of the machine uniformly along the surface of the tool to clean the tool.

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 vibrationless percussion tool is disclosed characterized by use of a piston mounted for reciprocal movement against a constant pressure force within a casing to cyclically impact an anvil disposed adjacent the distal end of the casing. A spool valve is disposed within the interior of the piston and is adapted to travel in unison with the reciprocating piston except during mechanical actuation initiated adjacent the extreme downstroke and upstroke position of the piston within the casing. The constant pressure force is continuously applied to one side of the piston and by mechanical actuation of the spool valve, the volume disposed on the opposite side of the piston is alternatively vented and pressurized to cause reciprocation of the piston against the constant pressure source.

Abstract: A diesel-engine pile driving hammer provided with interchangeable rams for use in a single, outer, cylindrical casing. A large diameter hole or orifice is provided in the casing between a pair of an array of alternate orifices which are capable of being plugged. The larger orifice or alternate orifices provide an air inlet-exhaust port or ports of sufficient dimension to enable all of the exhaust gases of combustion to be expelled in the time it takes a ram of designated weight to travel its upward stroke in the casing and to vary the swept volume of air introduced into the combustion chamber in the casing so that different weight, interchangeable rams may be accomodated in the same outer cylindrical casing to obtain prescribed impact energy values.

Abstract: A fluid operable hammer including variable volume exhaust chamber means for receiving motive fluid and improved motive fluid inlet and exhaust valve means cooperable with the exhaust chamber means.