Abstract: Briefly, the invention comprises a vibrator with an on-demand start-up system, that inhibits fouling the atmosphere, with one embodiment of the invention including an integral non-fouling start-up system wherein at least one of the bearing surfaces contains a surface adhered lubricant so as to provide an on-demand static start-up system and in another embodiment the on-demand start-up system is a dynamic system that can unbalance the differential forces on the piston therein to ensure that the vibrator will begin vibrating “on-demand”. Thus, two types of start-up systems are available one an on-demand static start-up system and the other an on-demand dynamic start-up system with either of the systems can be used alone or if desired in combination to provide redundant start-up systems.

Abstract: A linear vibrator having an internal cylindrical bearing surface forming a chamber therein and a fluid inlet to direct a fluid into the chamber with a one piece piston slideable located therein with the piston simultaneously rotatable and axially displaceable therein with the piston including a static port to bias the piston and thereby induce piston oscillation when fluid is introduced into the vibrator.

Abstract: Briefly, the invention comprises a vibrator with an on-demand start-up system, that inhibits fouling the atmosphere, with one embodiment of the invention including an integral non-fouling start-up system wherein at least one of the bearing surfaces contains a surface adhered lubricant so as to provide an on-demand static start-up system and in another embodiment the on-demand start-up system is a dynamic system that can unbalance the differential forces on the piston therein to ensure that the vibrator will begin vibrating “on-demand”. Thus, two types of start-up systems are available one an on-demand static start-up system and the other an on-demand dynamic start-up system with either of the systems can be used alone or if desired in combination to provide redundant start-up systems.

Abstract: Briefly, the invention comprises a vibrator with an on-demand start-up system, that inhibits fouling the atmosphere, with one embodiment of the invention including an integral non-fouling start-up system wherein at least one of the bearing surfaces contains a surface adhered lubricant so as to provide an on-demand static start-up system and in another embodiment the on-demand start-up system is a dynamic system that can unbalance the differential forces on the piston therein to ensure that the vibrator will begin vibrating “on-demand”. Thus, two types of start-up systems are available one an on-demand static start-up system and the other an on-demand dynamic start-up system with either of the systems can be used alone or if desired in combination to provide redundant start-up systems.

Abstract: The invention relates to a percussion mechanism for an at least percussively-operated hand machine tool, in particular a hammer drill or chisel, comprising a drive motor and a tool holder (10) for housing a tool, with a percussive pin (12) acting on the tool which is axially displaceable within a percussive pin guide (11). The percussive pin guide (11) has a body (13) enclosing the percussive pin (12). According to the invention, the body (13) is made from two materials of differing hardness. The invention further relates to an at least percussively-operated hand machine tool, in particular a hammer drill or chisel with a percussion mechanism.

Abstract: A pneumatically actuated lubricant pump wherein air is forced into the cylinder through a passage extending longitudinally through the piston rod. The rod is part of a piston assembly reciprocably mounted within a pump housing. The air passage extends from a lateral rod entrance through the rod and through the piston head. Air is forced into and released from the air cylinder through the passageway. In an alternative double-action embodiment, a second air flow passage extends through the pump housing alone directly to the air cylinder permitting compressed air to be alternately supplied to the opposite sides of the piston head.

Abstract: A true random vibration generator for use in mechanical vibration generation includes a housing, a piston, and a programmer. The housing defines a cylinder closed at an impact end. The piston is slidably disposed in the cylinder and propelled by a pressurized gas. The programmer is freely moveable in the cylinder between the piston and the impact end of the cylinder. As the piston is propelled towards the impact end of the cylinder by the pressurized gas, the piston strikes the programmer causing the programmer to randomly bounce between the impact end of the cylinder and the piston. The bouncing continue until the programmer impacts the housing and the cylinder at substantially the same time. The piston is then propelled back its original position by the pressurized gas and the impact with the housing. The above described piston cycle is repeated and continues to impart vibration energy to the housing.

Abstract: An impact borer having a shell and an air drive within the shell. The air drive includes a ram for reciprocation within the shell and a manifold joined to the shell. The manifold defining an inlet passage delivering air to the air drive and an outlet passage exhausting air from the air drive, and a duplicate passage interconnecting the inlet and outlet passages within the manifold.

Abstract: A pneumatic vibrator is disclosed including a tubular housing having closed ends, an inlet port in the housing through which a fluid, such as air can flow into the housing, and a free-floating piston in the housing having two passageways through which the pressurized air entering the housing through the inlet port flows to act alternately against opposite ends of the piston and cause the piston to reciprocate in the housing. Exhaust ports are located in the housing through which the air ahead of the moving piston is exhausted from the housing. A plurality of relatively small openings is located in the housing through which pressurized air can flow into the housing and provide a fluid bearing between the piston and the housing, and means are provided to supply the inlet port opening with air under pressure.

Abstract: A modular digital actuator is formed by interconnecting a plurality of modules. Each of the modules includes a housing having a pair of different sized axially extending cylinder sections in which is received a T-shaped piston with the top of the T mating with the larger cylinder and the leg of the T forming a piston in the smaller cylinder. The leg of the T is hollow and forms a cylinder to receive an axially extending piston forming shaft to thereby provide three preferably different sized cooperating piston and cylinder areas, one formed in the cavity or hollows of the leg of the T, a second formed between the top of the T surrounding the leg of the T and the junction between the larger cylinder section and smaller cylinder section and the third formed in the smaller cylinder section between a closed free end of the smaller cylinder section and the leg of the T surrounding the piston forming shaft. The top of the T forms a piston wall in a fourth hydraulic cavity.

Abstract: This heavy duty equipment comprises a working cylinder, a striking piston, an upper lid and a holder of a drill bit. An anterior side duct in the wall of an upper working space of the working cylinder, communicating via an upper filling duct and a posterior side duct with a storage space provided in the upper lid, and an anterior bypass duct communicating via an axial duct in an axial pin and a posterior bypass duct with the storage space, axially define in the upper working space of the working cylinder, a compression space confined by the inner wall of the working cylinder, and further by an anterior face of the upper lid and by the external surface of the axial pin. The upper lid together with the axial pin and the in-built storage space form an assembly group in which a water valve is received.

Abstract: A reversible impact-operated boring tool and a method for reversing the direction of operation of the same rapidly and safely is disclosed. The tool according to the invention possesses a second supply line for supplying pressurized fluid to the tool. The second supply line provides pressurized fluid to a directional valve within the tool. The tool operates in the forward mode for borrowing into the soil when pressurized fluid is supplied to this directional valve. When the pressurized fluid supply is terminated and the fluid is exhausted from the valve, the tool operates in the reverse mode. The tool according to the invention can be reversed safely without any need for hose manipulation and without turning off the primary fluid supply line.

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

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

Abstract: A ramming apparatus having a shortened length without sacrificing ramming power requirements is disclosed comprising a housing having a front end and a rear end, a pneumatically driven percussion piston having a front end and a rear end operatively mounted in the housing for oscillating movement between the front end and the rear end of the housing, a front pressure chamber provided in the front end of the housing, a rear pressure chamber provided in the rear end of the housing, a high pressure air supply line, a control device for controlling the application of pneumatic pressure on the percussion piston, the control device having a control piston extending axially from the rear end of the percussion piston into an opening of an end piece of the housing and having at least one radial control channel that is closable by the end piece, and an axial channel provided in the percussion piston, wherein when the percussion piston is in a forward position the axial channel communicates with the radial control channe

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

Abstract: In a device for controlling a pneumatic pile-driving or ram drilling apparatus having an internal, reciprocating ram, the control is effected in a forward stroke phase, a reverse stroke phase, and a subsidiary phase for the supply of air via a control device to a ram. The subsidiary control phase is a delay phase, in which subsidiary compressed air is fed to the front of the ram via time-delay means to take effect with an interval after that flow begins whereby to be substantially effective only in extending the reverse stroke of the ram. An apparatus is provided having a housing, in which the ram is reciprocated and compressed air admission is controlled by the control device which projects into the rear face of the ram and cooperates with the control ports in the ram to control the forward and reverse stroke movements of the ram. At least one supplementary control port, provides a time-delay device with which subsidiary compressed air is additionally fed on to the front of the ram.

Abstract: A pneumatic type of reciprocating movement device capable of a high cycle speed over a short stroke. A rod member with a flange is slidably mounted in a cylinder member such that the flange divides a cavity in the cylinder into a left and right portion. Intake and exhaust passages are moved in and out of communication with the cavity sides by the moving interface of the rod and cylinder, such that an alternating force is exerted on the flange sides causing the flange and rod member to move in a reciprocating motion without the use of an auxiliary system of valve switching.

Abstract: There is described apparatus for scabbling concretw which includes a hollow cylinder block having a top and bottom plate between which plates there is provided a smooth sided hollow cylindrical cylinder liner. The piston for reciprocation within the cylinder liner is also provided.

Abstract: A percussive air tool with a hollow cylindrical stepped housing having air inlet and air exhaust ports. A stepped hammer reciprocates inside the housing and has an axial central bore with a tube element disposed in the bore. The tool includes, work stroke and return stroke chambers, an air supply hose pipe with an air feeding valve, and a rod-clamping device arranged in the forward portion of the housing. The smaller step of the hammer has a neck portion or groove adapted to communicate the air inlet port with the interior of the larger step of the housing, an open annular cavity being formed between the tube element and the walls of the hammer bore.

Abstract: A pneumatic impact tool wherein a two-stage piston is reciprocable in the two-stage chamber of a cylinder. The tool which is to penetrate into a bone is mounted in the front portion of the cylinder and the piston strikes against such front portion in response to admission of compressed air against its rear end face. A relatively small annular shoulder of the piston faces forwardly and is continuously acted upon by compressed air. When the piston approaches or reaches the end of its forward stroke and rebounds from the front end portion of the cylinder, it seals the source of compressed air from its rear end face so that the action of compressed air upon the shoulder suffices to propel the piston rearwardly against the rear end portion of the cylinder at which time the piston reestablishes a path for the flow of compressed air against its rear end face so that it is propelled forwardly against the front end portion of the cylinder.

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 control device for working cycles of a self-propelled pneumatic boring device with a non-rotatable axially displaceable impact piston controllable by control edges of a control sleeve supported axially non-displaceably but rotatably and at its front end forming a control head with the control edges. The control head engaging in a cylindrical recess at a rear end of the impact piston cooperates with a radial main control opening formed in the impact piston in the vicinity of the recess. The control edges form two different pairs of the control edges, offset peripherally as well as axially such that respectively in one rotated position of the control sleeve only one of the pairs is aligned for cooperation with the main control opening. The impact piston is formed with at least one additional control opening which cooperates with the other pair and has a flow cross-section considerably smaller than that of the main control opening.

Abstract: Apparatus for the continuous adjustment of the stroke amplitude of the piston of a jack, the latter having a control member of which at least part is in the form of a rod, which is movable in rotation and in translation and cooperates with the said piston, wherein said rod has an extension in the form of a differential piston which is movable in translation and in rotation within a cylinder and defining also in the latter a chamber with a large cross-section and a chamber with a small cross-section, the latter being permanently connected to a pressurized fluid source, said differential piston having an inner cavity in which is located a second rod immobilized in translation and which can be angularly oriented, said second rod being provided with a cam having two opposite edges which can cyclically uncover and cover, during the rotation of the differential piston, at least two openings respectively connected to the two chambers.

Abstract: A starting mechanism for a reciprocating piston pneumatic hammer provides a passageway coupling a pneumatic piston subchamber to an exit port to exhaust pressurized pneumatic fluid from the subchamber during a start-up period. A pneumatic valve is provided to open the passageway as the hammer is started so as to create a pressure differential in the coupled piston subchamber, and thus prevent the piston from centering. The valve closes the passageway after the piston reciprocation has begun.

Abstract: A valveless pneumatic hammer comprises a hollow casing having a backhead assembly at one end and a bit assembly at the other, and a piston reciprocable in the casing. There is a chamber divider at the backhead end of the casing which co-operates with the piston for conducting fluid under pressure into alternate chambers, one at each piston end, for reciprocation of the piston. A chamber divider is located within the casing by a locating split ring which holds the chamber divider axially against the backhead assembly. The chamber divider also has a recess in the end thereof nearest the piston which together with a bore in this piston end, comprises the fluid chamber at this end of the casing.

Abstract: A compressed-air vibrator with a cylindrical housing confined between closure covers, within which there is arranged a piston reciprocated by the compressed air, whereby the compressed air is alternatingly introduced into the two working chambers through a central inlet groove in the cylinder bore and through axial bores which discharge through the end surfaces of the piston, and wherein the air is conveyed out of the chambers through outlets which are controlled by the piston edges.

Abstract: A tool for cutting percussive rotary drilling of boreholes includes a hollow casing having a bit. A hammer piston is installed in the casing for reciprocations and for cooperation with the bit for imparting impact impulses thereto. The hammer piston divides a working space of the casing into a workstroke chamber and a return stroke chamber which are alternately connected through distribution means provided in the casing with a source of a fluid under pressure for reciprocations of the hammer piston.

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

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

Abstract: Control device for the forward movement and rearward movement of self-driven pneumatic ram boring devices with an impact piston which is axially displaceable between two abutments in a tubular housing, with the axial forward movement and rearward movement of the ram boring device being controllable by rigid control edges of an adjustable control sleeve, the latter being supported on a bearing ring arranged in the rear part of the housing. Through the bearing ring there is led a part of the control sleeve forming a feed tube for the compressed air for connection to a compressed air hose, the sleeve having a piston-like control head containing the control edges; the control head engaging in a cylindrical recess at the rear end of the impact piston cooperates with radial control bores which are formed in the area of the recess in the impact piston. The control sleeve is mounted non-displaceably in the axial direction however rotatably in the bearing ring and is provided with at least four control edges.

Abstract: A cycle controlled sliding valve in a heating chamber combustion engine is provided. The valve includes a piston disposed for reciprocal movement within a cylinder, a piston-extension disposed for movement within the cylinder, a connecting rod connected to the piston, a pinion carried by the connecting rod, and a rack engaged by the pinion. The rack engages the piston-extension such that the latter is capable of movement in the axial direction of the cylinder away from or towards the piston. Such movement is caused by the swinging of the connecting rod due to crankshaft rotation. A path is provided within the cylinder walls which leads to the heating chamber. When an opening in the piston-extension is aligned therewith, communication is established between the cylinder and the heating chamber. In operation, the path leading to the heating chamber will open later during the up-stroke and will close later during the down-stroke.

Abstract: Fluid-actuated percussion mechanism includes a housing with an internal cylindrical space receiving a reciprocating piston dividing the space into a working stroke chamber and an idle stroke chamber. The mechanism further includes distributing means mounted in the housing and communicating the chambers and the source of the working fluid. The housing also accommodates a work-performing member adapted to receive impacts from the piston. The distribution means includes at the inlet of at least one of the chambers a valve made in the form of a resilient element. The surface of the distribution means has made therein valve seats of which the number corresponds to that of inlets for supplying the working fluid into the chamber.

Abstract: A piston vibrator comprising a cylindrical housing having a chamber with a free floating piston therein. The free floating piston is axially moved by a pressurized medium. Piston amplifying structure is provided for regulating the effective mass of the piston and thereby the amplitude and frequency of movement thereof in said cylindrical housing.

Abstract: An impact mechanism operated with gaseous fluid under pressure fed from a source of fluid having a casing with an inner cylindrical space. A piston is accommodated for reciprocation within the cylindrical space of the casing to divide the space into a work stroke chamber and an idle stroke chamber. The chambers are in communication with the source of gaseous fluid through a distribution means for reciprocation of the piston under the action of fluid. A valve is provided over the inlet port of at least one chamber to admit gaseous fluid under pressure thereto. The valve comprises biasing means in the form of a helical compression spring mounted coaxially with the inlet port of the chamber. One end of the spring is tightly sealed and the other end is fixed over the inlet port of the casing. Gaseous fluids under pressure is admitted to the chamber through gaps between the turns of the spring when the spring is expanded, and the admission is interrupted when the spring is compressed.

Abstract: A hydraulically operated vibration exciter for a vibrating compactor of the kind comprising a piston in a cylinder, the piston and cylinder being arranged to move to and fro relative to each other, a source of liquid under pressure, a pressure line connecting the source to the cylinder and means for causing the liquid to move to and fro between the source and the cylinder to bring about the relative movement between the piston and cylinder is cooled by a method in which, during the relative movement, a quantity of the liquid is withdrawn from the cylinder and this quantity is not returned to the cylinder in the subsequent stroke, but is replaced by a fresh quantity of liquid at a lower temperature.

Abstract: The fluid-actuated percussion mechanism includes a housing with an internal ylindrical space wherein a reciprocating piston, which divides the space into a working stroke chamber and an idle stroke chamber, is received. The mechanism further includes fluid distributing means and a distribution unit mounted in the housing for placing the chambers and a source of the working fluid in communication. The housing also accommodates a work-performing member adapted to receive impacts from the piston. The distribution unit includes at the inlet of at least one of the chambers a valve made in the form of a resilient annular element. The surface of the distribution unit has valve seats made in it, the number of which corresponds to that of the inlets for supplying the working fluid into the chambers. The resilient valve element is taut about the surface of the distribution unit in opposition to the inlets and encircles the periphery of the unit.

Abstract: A concrete strike-off vibrator is characterized by a manifold member having at least one cylinder assembly disposed in a force-transmitting relationship therewithin. The manifold includes a pressurized fluid inlet adapted to introduce a pressurized fluid into the interior volume of the manifold. The cylinder assembly includes a piston adapted to define first and second volumes within the cylinder assembly and has associated therewith an intake for introducing pressurized fluid from the interior volume of the manifold into the first and second volumes defined within the cylinder assembly. Included is an exhaust isolated from the intake and from the interior volume of the manifold for venting the first and the second volumes within the interior of the cylinder assembly.

Abstract: A pneumatically controlled tamper includes a cylinder which has a lateral supply opening for compressed air and which is integral with a foot. A piston with a symmetrical structure possesses two internal channels provided with check valves. The first channel terminates at one end on the lateral surface of the piston, above its median plane, and at the other end at the bottom of the piston in a lower chamber connected to the atmosphere by an escape opening. The second channel terminates at one end on the lateral surface of the piston, below its median plane, and at the other end at the top of the piston, in an upper chamber connected to the atmosphere through another escape opening. When the piston is on the bottom of the cylinder, the supply opening supplies the first channel, this arrangement making it possible to initiate a reciprocating movement which is maintained without any distribution system. The invention is used preferentially for soil compacting.

Abstract: The apparatus has a pointed-nose hollow cylindrical body with a closed rear portion. Disposed inside the body, so as to enable reciprocation and rotation about the axis of the body, is a stepped striker which can be locked against rotation about the axis of the body in two positions, the positions corresponding to forward and reverse movement of the apparatus.For the purpose of admitting compressed air into a forward working chamber, the striker is provided with a central passage permanently connected to a rear working chamber and at least two radial passages which provide communication between the central passage and an outer cylindrical surface of a large step of the striker. The radial passages are displaced relative to each other both circumferentially and longitudinally along the axis of the body.

Abstract: A self-propelled pnuematic burrowing device having an axially reciprocating percussion plunger arranged inside a tubular casing so as to strike a percussion head at the forward extremity of the casing, thereby advancing the device through the ground by crushing and/or displacing the material in the path of the device, the percussion head being freely displaceable between axial abutments defined by a guide sleeve of the casing, the displaceability being slightly in excess of the advance of the device per stroke and adjustable through the insertion and removal of split spacer rings. The air controls of the device, located in the rear portion of the casing, include a control barrel with an enlarged control head and a gradually widening central air supply channel.

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

Abstract: A pneumatic impact tool comprising a housing, an open ended cylinder inserted therein and a hammer piston reciprocably guided within the cylinder. In the forward end of the cylinder there is received the shank of a chisel onto which the hammer piston imparts impacts. The piston is a differential piston having its big end facing the chisel and forming around its rear, small diameter neck a rear annular, constantly pressurized chamber which continuously communicates with the pressure air inlet through a pulsator chamber. The forward cylinder chamber, enclosed between the chisel shank and the piston front area, is intermittently pressurized through an internal passage of the piston, which passage is periodically connected to the pressure air inlet by means of valve openings in the piston neck.

Abstract: The present invention relates to pneumatic impact devices and can be used to the best advantage for making holes in compacted soils.The device is provided with a hollow casing which accommodates a stepped ram with the maximum-diameter step in its front part. This step has longitudinal channels which open at one end into a working chamber defined by the maximum-diameter step and the side walls of the casing and serving for receiving compressed air from the compressed air line, with the air moving the striker to impart a blow after which it is discharged through holes in the casing.

Abstract: A fluid actuated, valveless sanding tool is disclosed which comprises a housing containing a cylinder, a double-ended piston mounted for reciprocal movement within the cylinder, a mounting plate to which an abrasive tool can be attached, and a double rack and pinion connecting means reciprocally driving the mounting plate. A fluid supply system delivers pressurized fluid to a central portion of the bore and a vent system permits venting of the ends of the cylinder. The piston has two end seals and three internal, main seals which maintain a fluid tight relationship with the inner cylinder wall. Two internal passages in the piston are in communication with the annular areas between the three main seals and the respective ends of the piston.

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

Abstract: Power hammers for driving piling, and the like, free of any complex valve mechanism likely to require attention and comprising a working cylinder having an anvil at the lower end thereof and a ram operative as a piston in the cylinder, cooperative with the anvil and surrounding walls of the cylinder to form an expansion chamber, the ram having a passage extending from an annular groove intermediate the ends of the ram, down through the lower end to the expansion chamber and the cylinder having pressure supply and exhaust ports to register with the passage and to be uncovered by the ram, in lower and upper positions of the ram in the cylinder, whereby the essential functions of the hammer are automatically effected in the normal operation of the ram. Pressure controlled valves may be added to automatically hold desired pressures and release opposing pressures on the ram.