Abstract: A hand-held pneumatic impact tool for use in fine hand working operations includes a mechanism for adjusting impacting characteristics of the device that is conveniently located and adjusted by the user. The mechanism includes an annular band protruding around the outside diameter of the body of the impact tool that may be turned for adjusting the piston stroke length and speed at which impacts occur.

Abstract: An operating system for a hydraulic rock drill in which the impact piston and rotation motor are hydraulically connected in series. The advantages are simplicity of connections, automatic torque increase when required without reducing impact power, and automatic reduction of impact power if the rotation stalls.

Abstract: Depending on the working and application conditions, it may be desirable to equip fluid-operated percussion devices with a mechanism that protects against no-load strokes, particularly in the interest of avoiding undesired stress. In the present case, this protection mechanism is configured such that the control unit that influences the movements of the percussion piston is blocked by a safety element in the form of a multiple-position valve, and the percussion device is halted if the percussion piston overshoots the extended position occurring in normal operation by a defined distance, thereby assuming a no-load-stroke position. The safety element (21) that acts on the control unit (5) of the percussion device (1) is automatically controlled, notably such that it is not switched to be active until some time after the startup of the percussion device (1) acted on by the working pressure. The percussion device (1) can therefore start up without being influenced by the safety element (21).

Abstract: A control system for a heavy duty hydraulic hammer reduces blank firing of the hammer. The control system provides a reduced flow of hydraulic fluid to the hammer for a selected period of time upon actuation of the hammer and then provides full hydraulic flow increasing the frequency of impacts to full rated values.

Abstract: The present invention provides a device for breaking up a paved surface which attaches to a host transport, such as a skid steer or backhoe, having a hydraulic power supply and preferably comprises a closed hydraulic system which includes a regenerative and concentric type double hydraulic cylinder arrangement adjustably supported within a vertical frame. The cylinder is operably attached to a weight such that when fluid is pumped into a first chamber, a piston drives a rod, thereby lifting a weight while at the same time, the piston forces hydraulic fluid from a second chamber to the host. The piston separates the first chamber from the second chamber within the cylinder. Upon reaching a prescribed height, a valve is opened, allowing fluid to flow from the first chamber into the second chamber, thereby allowing the weight to drop rapidly under the influence of gravity.

Abstract: A drilling tool, the drill head (16) of which can be connected either to a drill (10) or a casing string (28), is also fitted with an automatic direction reversing mechanism (64) which is designed so that the driven part (14) of the drill head (60) executes backward and forward movements of less than 90°, but preferably 20° to 30°. In this way the drill head can also strike the casing string when sinking it.

Abstract: An electrohydraulic pavement breaker system having cavities (28, 30) which are filled with hydraulic fluid (oil) or gas, and which provide mass spring system which is resonant at a frequency which is especially adapted for breaking and rubblizing concrete pavement. The resonant mass (18) is in impacting relationship with the pavement through a shoe (12), which shoe (12) may be part of an assembly which is pivotally mounted on the support structure (10) of the breaker and is vibrated with the mass (18) to repeatedly impact the pavement at the rate of the resonant frequency. An electrohydraulic control system is responsive to the motion and average position of the mass of the vibrator and controls the driving force so as to be at the resonant frequency of the mass spring system and have the amplitude and energy suitable for breaking the pavement.

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 hand-held hammer drill has a housing and an electric drive motor arranged in the housing. A tool spindle is arranged in the housing and configured to receive a tool. The tool spindle can be driven in rotation by the electric drive motor. The tool spindle has a longitudinal axis and is oscillatingly moveable in a direction of the longitudinal axis. A hammer mechanism is provided to move the tool spindle oscillatingly in the direction of the longitudinal axis. A hydraulic drive is arranged in the housing and configured to drive the hammer mechanism. The hydraulic drive has a hydraulic pump generating a hydraulic pressure for driving the hammer mechanism.

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 percussion power tool assembly (10) comprises a hand-held percussion power tool (11), a chamber (12) mounted on the tool (11), and a fluid reservoir (14) supported independently of the tool (11). The percussion power tool (11) has a body (20) housing a reciprocating hammer (22) which impacts against tool bit (24) in a conventional manner. The hammer (22) is operated by compressed air admitted though valve (26) in feed line (28). The chamber (12) communicates with the fluid reservoir (14) though flexible hose (16). The chamber (12) surrounds the body (20) and has a flexible lining (30) defining a bladder which inflates/deflates in sympathy with fluid filling, or emptying from, the chamber. The deadweight of the hand-held part (18) of the assembly (that is, the tool and chamber combined) is varied by transferring fluid, e.g. water, in the reservoir (14) to the chamber (12), and reduced by returning transferred fluid to the reservoir (14).

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: An arrangement in a rock drill comprising a shank and a percussion piston and lifting sleeve for moving the shank towards percussion piston, and a method of controlling rock drilling. The arrangement comprises a lifting sleeve around the shank and a plurality of cylindrical lifting pistons around the shank. In the method, upon downward drilling, the magnitude of the feed force of the rock drill is decreased as the number of extension rods increases, and a force is set to act on some lifting pistons to move the shank towards the percussion point.

Abstract: A ram device has a cylindrical housing (10) in which is arranged a pressure medium actuated impact piston and a control unit for controlling the pressure medium flow into the housing (10) and which housing (10) at its rearward end is provided with a pressure medium connector (16) and is closable by a closure part (12). The closure part (12) is threadable into an end portion (22) of the housing (10) provided with an internal thread by an externally threaded section (18) and has a second threaded section (20) which stands in engagement with a counter element (22) which abuts a housing surface (40) perpendicular to the housing axis.

Abstract: A pneumatic tool is disclosed. The pneumatic tool has a hollow housing with a handle extending therefrom, the handle having a chamber defined therein and an air passage communicating with the housing, an actuating mechanism mounted in the housing to actuate a tool shank and a cap securely attached to said handle to cover the chamber so as to form an oil reservoir in the handle. The pneumatic tool further has a control member mounted in the actuating mechanism to control the opening and closing of a discharge passage formed in the actuating mechanism. The disclosed pneumatic tool can limit the size of the pneumatic tool and let the air completely flow out so as to improve the convenience and operational effectiveness of the pneumatic tool.

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 percussion piston for use in a drilling apparatus includes a drill bit and at least three tubular parts which increase in diameter in a direction extending from the drill bit toward a rear end of the piston. The piston further includes flanges positioned between the tubular parts and a first corresponding delivery space at the rear end of the piston. At least two additional corresponding delivery spaces are positioned between the first corresponding delivery space and the drill bit. Channels allow the transport of pressurized hydraulic fluid to and from the first and additional corresponding delivery spaces such that an energy pulse produced by impact of the piston on the drill bit is almost completely absorbed by the drilled object.

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: An elongated tube has a high pressure feed line on one end and an impact head on the other end. A tube intermediate the ends of the tool houses two cylinders having one piston is in each cylinder. The two pistons are tied together by a piston rod extending through a bulkhead dividing the two coaxially aligned cylinders.

Abstract: A pneumatic scraping tool includes a pneumatic hammer assembly including a cylinder in which a piston reciprocates for repeated impact against an anvil or blade holder which is rotatably received within an end of the cylinder and carries a scraping blade. The anvil has an annular flange which stops its insertion in the cylinder, and is retained in place by a nut threadedly engaged with the cylinder and having an end wall spaced from the cylinder end a distance slightly greater than the flange thickness to permit reciprocation of the anvil. Exhaust air passes along a groove in the outer surface of the cylinder to an annular chamber in the nut and thence through four exhaust ports exiting at the end wall of the nut. A plug portion of the anvil projects through a central opening in the nut end wall and is received into a socket in a blade housing. Blade fingers project laterally into the socket.

Abstract: A pressure amplifier can be mounted above a drill bit at the lower end of a drill pipe for generating an increased fluid pressure in a drilling fluid flow to, for example, obtain an increased drilling effect, A reciprocating piston in a cylinder has at one side (a low pressure side) a large piston area and also has a first opposite piston area and a second opposite and relatively small piston area, which generates an increased pressure. A valve device controls drilling fluid flows to and from the piston. Beyond one end of the cylinder there is provided a hydraulic rotary motor adapted to be driven by the pressure difference between the drilling fluid flows in the drill pipe and an annulus. A transmission mechanism converts the rotation of the hydraulic motor into intermittent movements of the valve device between two operative positions.

Abstract: An elongated tube has a high pressure feed line on one end and an impact head on the other end. A tube intermediate the ends of the tool houses two cylinders having one piston is in each cylinder. The two pistons are tied together by a piston rod extending through a bulkhead dividing the two coaxially aligned cylinders.

Abstract: A hydraulically driven hammer has a piston which contains metal piston rings on a constant diameter section. The housing has a plurality of axially spaced apart radial ports that extend through the housing into the bore. A valve supplies fluid to the ports to control reciprocation of the piston.

Abstract: Pressure amplifier for mounting above the drill bit at the lower end of a drill pipe for generating an increased fluid pressure in a drilling fluid flow, for example for obtaining an increased drilling effect. A reciprocating piston in a cylinder is designed with a large piston area at one end (low pressure side), a relatively small piston area at the opposite end (high pressure side), and an annular surface formed at the transition between the two ends. The pressure converter also includes a control valve, an actuator, and a drilling fluid valve to control drilling fluid flow to and from the cylinder.

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 vibration generating apparatus comprises a cylinder assembly (6) having a cylinder and a piston (3) slidably inserted in a cylindrical bore (2) of the cylinder for defining a first pressure receiving chamber (4) with a small pressure receiving area and a second pressure receiving chamber (5) with a large pressure receiving area. The piston (5) is selectively movable in one direction and in the other direction responsive to pressures in the pressure receiving chambers. A switching valve (9) has a first pressure chamber (13) with a large diameter, a second pressure chamber (14) with a small diameter, a pump port (10), an auxiliary port (23), a principal port (11) and a tank port (12). The switching valve (9) takes a first position under a pressure within the first pressure chamber and takes a second position under a pressure within the second pressure chamber.

Abstract: An elongated tube has a high pressure feed line on one end and an impact head on the other end. A tube intermediate the ends of the tool houses two cylinders having one piston is in each cylinder. The two pistons are tied together by a piston rod extending through a bulkhead dividing the two coaxially aligned cylinders.

Abstract: An apparatus for generating impacts which has a hydraulic cylinder and a reciprocating piston. The hydraulic cylinder has an impact chamber, a cavity which receives and diverts fluid, and a throat which connects the impact chamber with the cavity. When the pressure line is connected to the cavity, the piston is lifted to an upper position. When the overflow line is connected to the cavity, the piston drops down such that the piston enters and covers the throat at the impact chamber. The pressure in the chamber remains low as the chamber is sealed by the piston entering the throat, where the energy loss is insignificant. The piston enters into the throat such that it is stopped and presses against the fluid inside the impact chamber, and thereby generates an impact therein. The piston is lifted up to repeat the cycle, when the cavity is connected to the pressure line.

Abstract: A rock drill with a percussion mechanism which includes a piston, a body in which is formed a chamber, at least a first cylinder which is located in the chamber and which, on an inner side, forms at least part of a sleeve for the piston, and a valve, for controlling movement of the piston, which is located on an outer side of the first cylinder. A stop structure integrally attached to the first cylinder prevents the valve from being removed.

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: An apparatus for generating impacts which has a hydraulic cylinder and a reciprocating piston. The hydraulic cylinder has an impact chamber, a cavity which receives and diverts fluid, and a throat which connects the impact chamber with the cavity. When the pressure line is connected to the cavity, the piston is lifted to an upper position. When the overflow line is connected to the cavity, the piston drops down such that the piston enters and covers the throat at the impact chamber. The pressure in the chamber remains low as the chamber is sealed by the piston entering the throat, where the energy loss is insignificant. The piston enters into the throat such that it is stopped and presses against the fluid inside the impact chamber, and thereby generates an impact therein. The piston is lifted up to repeat the cycle, when the cavity is connected to the pressure line.

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: The impact hammer comprises a working piston (22) exerting impacts onto an impact surface (23). The hydraulically driven working piston (22) is reciprocatingly controlled by a control means (40,41). At the rearward end of the working cylinder (21), there is a rear chamber (50) into which the projection of the piston (51) immerses. Connected to the rear chamber (50) is a pressure gas reservoir (52) which is charged with each return stroke of the working piston and discharges with the subsequent working stroke.

Abstract: A hydraulic reciprocating percussion tool, particularly adapted for drilling applications, comprises an elongated cylinder, opposed fronthead and backhead members and a central bore in the cylinder for supporting a reciprocating piston hammer. The piston hammer has reduced diameter end portions which have respective tubular sleeve valves disposed in sleeved relationship thereon and engageable with valve retainer members on the reduced diameter portions for effecting movement of the valves with the piston hammer. The head members include tubular sleevelike stem portions which cooperate with the respective valves to valve pressure fluid to and from opposed chambers in the cylinder to effect repeated impact blow delivering strokes to a shank member disposed in a chuck connected to the fronthead.

Abstract: An impact device 1 that is continuously controllable in terms of impact rate and impact force contains a percussion piston 25 that can move back and forth in the inner boring of the cylinder 3, and that is controlled via a rotary valve 15 having as rotary engine 16. The rotary valve 15 and the rotary engine 16 are positioned separately from the percussion piston 25, either on or in the cylinder 3, and are linked only via portings 20, 22, 24 to the pump connection 21 and the tank connection 23, or to the double-sided piston areas A1, A2, so that the valve can be used with practically any type of impact device, without requiring substantial alteration of its structural dimensions. In addition, an advantageous continuous control of impact rate and impact force with a constant power output is ensured.

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 device for distributing oil under pressure including a head (2) within which, inside a chamber (24), a shuttle (5) slides provided with a shank (5a) sealingly sliding within an end cap (6) and on whose head surface (19) oil at the feed pressure acts coming from a switch duct (18). The head (2) is provided with a feed hole (8) connected to the chamber (24) and is closed at the other end by a shutter (7) connected to a drain hole (9), while the shuttle (5) is provided with an inner cavity (26) and end ducts (25) and it is shaped so as to have in the chamber (24) opposite transverse surfaces (22, 23) whose difference of area in favour of the surface (23) at the end where the shank (5a) is located is smaller than the area of the head (19) of the latter. A hydraulic hammer including the device is provided with a pair of outflow orifices (17, 20) located so that the first orifice (17) is uncovered by the ram (4) at the end of the return travel and the second orifice (20) at the end of the descending travel.

Abstract: The impact hammer comprises a working piston (22) which is displaceable within a working cylinder (21) and controlled by a control means (40,41) in such a manner that it exerts impacts onto an anvil surface (23) of an adapter (24) which can be connected to the object to be advanced. When retracting the object, a return impact piston (51) exerts impacts onto the adapter (24) in opposite direction. Thereby, it is achieved that the object can be better released from the drill hole.

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 impact device includes a cylinder and a plunger which is received within the cylinder and movable in forward and rearward directions. The plunger includes a first and a second pressure receiving surface for receiving pressure of a pressurized fluid so as to apply force to the plunger in the forward and rearward directions, respectively. An additional pressure receiving surface is formed on the plunger for receiving the pressure from the pressurized fluid so as to apply force in the same direction as one of the first and second pressure receiving surfaces. A first control device is operable to selectively apply the pressure of the pressurized fluid to the additional pressure receiving surface.

Abstract: Liquid driven hammer machine with a machine housing (1) and a hammer piston (2) moveable to-and-fro in guides (4,5) in the machine housing. The guides are made with an intermediate section (6) and end sections (7,8) on either sides thereof. The slot between the intermediate section and the hammer piston is less than, preferably one half of, the slot between the end section and the hammer piston at the end of the end section turned away from the intermediate section. The intermediate section has according to an advantageous embodiment an ax/al extension which is approximately one third of the length of the guide.

Abstract: This invention relates to a drive unit comprising a frame; a rotating shaft, a first fluid motor presenting a cam fixed with respect to the frame; and a cylinder block fast with the shaft driven by the first motor at a first speed of rotation.According to the invention, the shaft presents a recess conveying a drilling fluid; the cylinder block of the first motor is coaxial to the axis of rotation; drive unit comprises a second motor coupled in rotation to the shaft and driving it at a second speed of rotation higher than the first speed of rotation; a first pinion gear is fast with and coaxial to the shaft; the second motor presents an output shaft fast with a second pinion gear meshing with the first pinion gear; and the first motor is of the type with "disengageable pistons".One application is the production of a high-performance drilling assembly.

Abstract: A pneumatic hammer is provided which includes a working piston (16) movable in a working cylinder (22) and defining therewith front and rear cylinder working chambers (23, 24, respectively). The working piston (16) impacts upon an anvil (15) to drive a drill bit (12) through utilizing a source of compressed air. An adjusting mechanism (37) adjusts the length of the return stroke of the working piston (16) in dependence upon the supply pressure of the compressed air.

Abstract: A hammer of the type having an impact tool driven by pressurized fluid has a hammer body portion with a closed rearward end and an open forward end and a piston longitudinally movably housed within the hammer body portion for striking a tool mounted at the open forward end of the hammer body portion, to thereby impact an object with the tool. The hammer has a fluid valve housed within the closed rearward end of the hammer body portion rearwardly of the piston and in communication with a source of high pressure fluid for driving the piston. The fluid valve has a valve body portion defining an interior chamber and a continuous exterior side wall, and a longitudinal opening in communication with the interior chamber. The valve body has a first body portion and second body portion which is identical to the first body portion and positioned longitudinally in relation thereto within the closed rearward end of the hammer body portion.

Abstract: The invention concerns a rock drill (2) for activating a rotatable and reciprocable drill steel assembly (FIG. 1 ). A reversible motor (50) is coupled to a striking bar (3) for rotating the drill steel. The striking bar is struck by a percussion piston (10). A rotary fluid valve (15) is operating the piston. A disconnectable coupling (37,38,43) in normal operation couples both the valve (15) and the striking bar (3) with the motor (50). In special modes the motor operates only the percussion piston, e.g. for retracting a drill rod, or only rotates the striking bar (3), e.g. for connecting and disconnecting drill rods.

Abstract: In an impact drilling apparatus, an impact hammer is provided that includes a body portion and a piston head on the body portion. The piston head has a larger outer periphery than the body portion. The body portion and the piston head have substantially the same cross-sectional area at all points along a longitudinal axis of the hammer. The piston head is disposed at one end of the body portion and is funnel-shaped.

Abstract: An impact device for breaking up and separating hard material comprises an actuating system for providing a faster cycle rate as well as an increased impact force. More specifically, the device includes a pair of pistons movably arranged in a cylinder to cooperate in compressing the gaseous component prior to initiating the blow. A closed tube is provided to fluidly interconnect opposite chambers adjacent the two pistons to coordinate the different movements of the pistons to effect the desired compression. The impact device is particularly well suited for use in an impact bucket.

Abstract: In a rammer for internal ramming of pipes, having its rear end connected with the rear end (viewed in the direction of advance) of the driven pipe, the application of the driving force is improved by a mechanically simple connection.

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.