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 striking tool for surgical instruments with a sleeve-shaped gripping part, a tool holder which is slidingly displaceable in the latter in the longitudinal direction thereof, and an oscillatingly driven piston which is slidingly displaceable in the gripping part in the longitudinal direction thereof and has two striking surfaces which strike corresponding contact surfaces of the tool holder and thereby act upon the latter with impulses acting in opposite directions, to enable selective generation of blows in the striking direction and in the pulling-out direction without converting the tool, it is proposed that the actual stroke of the piston in the gripping part be limited such that is it smaller than the double-strike stroke which the piston would have to cover, with the tool holder held firmly in the gripping part, from the striking of the first striking surface against the contact surface to the striking of the second striking surface against the second contact surface, and that the tool holder be mou

Abstract: In a water driven down-the-hole rock drill, the rearward end of an associated hammer is provided with a drive piston reciprocable in a cylinder located adjacent the rear of the drill. The front end of the hammer is guided for reciprocation in a bearing located adjacent an anvil of a drill bit. Between the cylinder and the bearing the hammer is elongated and enlarged diametrically relative to the piston. The enlarged hammer portion reciprocates freely in a chamber formed by an outer casing of the drill. Drive water is expelled from the cylinder and flushes the hole drilled by the bit. An open ended tubular valve reciprocates to control a duct connecting the interior of the valve to coaxial through-flushing channels in the hammer and the drill bit.

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: An improved reversing mechanism in an impact hole drilling tool having a tubular body with a forward ground piercing end and a rearward pneumatic supply end. The reversing mechanism includes a slot coacting with a key to guide an interior tool valve in relative longitudinal movement when shifted from one of its directional motion positions to the other. The mechanism also has elements for biasing the valve mechanism longitudinally toward its forward motion position and rotationally toward at least one relative mechanism orientation wherein the key and slot are not aligned. Tool direction reversal, from forward to reverse direction, occurs without interruption of the pneumatic supply by applying rotational and pneumatic longitudinal force against the biasing elements, returning the tool to its forward direction position upon interruption of the pneumatic force.

Abstract: A conventional stake member having an annular post mount joined to the upper end of the stake to form a socket for receiving the lower end portion of a right angular extension of the elongated mounting member of a slide hammer. A right angle hammer member has a lower terminal edge for forming a mating fit with the top edge of the stake when the extension extends into the socket and a pin removable attaches the stake to the hammer member and extension. The upper end portion of the rod which forms part of the mounting member mounts an anvil having a top surface and a bottom surface to be selectively struck by a slide member for the selective one of pulling the stake and driving the stake into the ground, the slide member being reciprocal relative to the mounting member. The anvil is located within the slide member. The lower end portion of the rod is welded to the apex of the extension.

Abstract: In a ram boring machine having a striking piston that can be moved axially in a housing and whose movements are controlled by a control pipe that is connected to a compressed air hose and is mounted in an elastic intermediate piece arranged in the housing, arranging the elastic intermediate piece on the control pipe and/or in the housing facilitates the assembly of the intermediate piece. Furthermore there is less damage to the housing, the control pipe and the compressed air hose and even the control pipe can be mounted and disassembled easier.

Abstract: The invention relates to an extraction device used for extracting pneumatically actuated impact tools and the like from boreholes. The device includes a carrier member 1, a reciprocable hammer 2, and a sleeve, 13. The carrier is adapted to be connected to a drill rod secton. Reciprocation of the hammer relative to the carrier may be used to effect extraction. Fluid passages are provided for conveying fluid under pressure through the device in order to cause the hammer to reciprocate.

Abstract: A firefighter's barrier penetrator and agent injector having an extendible slide rod to guide a slide hammer to strike a penetrating body to drive its point through the barrier. The slide rod can be retracted into the body to minimize the length of the penetrator while being carried. A nozzle is slidably mounted in the body to be extendible into the structure for injection purposes, again to minimize the carrying length. Retention devices releasably hold the rod and nozzle in their retracted positions.

Abstract: In a self-propelled reversible boring ram, selection of forward/reverse boring modes is determined by the position of a control piston. A concentric supply pipe to a source of working fluid pressure connected to coaxial fluid inputs on the ram. Working fluid pressure for an impacting piston (hammer) is supplied through the input. For forward mode operation, pressure from a coil spring and reactive force on the piston is overcome by working fluid pressure on servo pistons. Restricting fluid pressure on the pistons allows the piston to move to reverse mode operating position.

Abstract: A percussion drill having a control device for controlling its travel forwards and/or backwards is provided with an adjusting and locking device for an axially movable control sleeve (4), this adjustment reversal device being adapted to be controllably operated with compressed air from a control station. A reliable reversal from forward to backward travel of the percussion drill is thus possible even in very long boreholes and even in the event of the collapse of the borehole.

Abstract: Slide hammer apparatus including means for restraining and non-rotatively driving and pulling fence posts. A handled, hammer section mounts in concentric, sliding relation to a main body which surrounds a fence post and contains upper and lower stops. At least one stop includes an adjustable clamp means and anvil acting pin for securing a post to the main body and permitting reciprocal motion.

Abstract: A ram boring machine having a striking piston that is axially displaceable in a housing, of which the forward and backward movement is controlled by a control sleeve connected to a supply hose and which engages in a cylinder chamber of the striking piston, and by one or more corresponding control openings in the striking piston, wherein the control sleeve is loaded both axially and torsionally, has axial and rotational stops and is rotatable and axially displaceable in a guide sleeve arranged at the rear end of the housing.

Abstract: A self-propelled, pneumopercussive, cyclic action, ground penetrating machine (200) has decreased energy consumption and increased average working velocity compared to conventional machines. This is obtained in part by a valve-operated air-distribution mechanism (203) having separated forward and reverse compressed air supply lines (35, 37), which mechanism (203) does not limit the length of the forward and backward strokes of the striker (202). This mechanism allows the backward stroke chamber (75) to be connected with the atmosphere during the entire forward stroke of the striker (202). This eliminates generation of an air buffer in the backward stroke chamber (75) and, consequently, the striker (202) does not lose part of its kinetic energy before impact.

Abstract: A stake puller having a slotted, planar base with a horizontally extending handle and a vertically extending slide bar, the centerline of the handle and slide bar being in the same vertical plane. The slot has angled sidewalls to grip a stake and a hammer head slides back and forth on the slide bar to transmit pulling force to a stake.

Abstract: The present invention provides a self-propelled impact boring tool which, according to one aspect of the invention, has a simplified tail assembly so that the tool can be readily assembled and dissambled to allow replacement of worn parts. Such a tail assembly includes a nut and an end cap which can be secured together by a series of conventional bolts which extend into threaded holes in the nut. The nut, which is screwed into the rear end of the tool body, can be clamped in position with the screws with far less torque than would otherwise be required with a conventional, unitary tailpiece.

Abstract: In a water driven down-the-hole rock drill, the rearward end of an associated hammer is provided with a drive piston reciprocable in a cylinder located adjacent the rear of the drill. The front end of the hammer is guided for reciprocation in a bearing located adjacent an anvil of a drill bit. Between the cylinder and the bearing the hammer is elongated and enlarged diametrically relative to the piston. The enlarged hammer portion reciprocates freely in a chamber formed by an outer casing of the drill. Drive water is expelled from the cylinder and flushes the hole drilled by the bit. An open ended tubular valve reciprocates to control a duct connecting the interior of the valve to coaxial through-flushing channels in the hammer and the drill bit.

Abstract: A microposition table is held in place by the friction between a series of plates contacting one another. Movement is effected by forcing a small burst of air through a series of channels to drive metal pistons each held captive inside an elongated cylinder. The impact of each piston striking one or the other of the cylinder ends imparts sharp mechanical impulses to each plate driving the plate a small distance in the direction of the impacting force. Repeated impacts by repeated bursts of air move the plates the desired distances with respect to one another.

Abstract: A pneumatic percussive device has a casing (1) accomodating a movable hammer piston dividing the interior space of the casing (1) into two chambers. One of these chambers (7) alternately communicates, by means of an air distribution arrangement (3) having a movable actuator member (8), with a compressed air source and with the environment. In addition, said chamber (7) communicates, via a throttling passage (27), with a cavity (10) of the air distribution arrangement (3) the pressure in which ensures movement of the actuator member to one of its limit positions.

Abstract: A ram boring machine having a pull-and-turn reversing gear which comprises a striking piston axially displaceable in a tubular housing and a rotatably mounted control pipe with control openings such that forward and backward movement of the machine is controlled by moving the control openings over corresponding radial control openings in the striking piston, the control pipe having at least two parts with the rear part (viewed in the ramming direction) being connected to a supply hose, being relieved of the working pressure, and being connected to the bearing pipe by way of a force-loaded locking device which can be unlocked axially by traction on the supply hose against the loading force. This arrangement on the one hand prevents undesired reversal and on the other hand enables reversal to be effected under pressure.

Abstract: A pressure-medium driven ram boring machine for boring in the earth, having an impact tip acted on by a percussion piston reciprocating in the machine housing, wherein the impact tip is arranged to be radially adjustable in the housing whereby controlled directional changes of the machine can be effected.

Abstract: A ram boring implement having a pneumatically or hydraulically driven percussion piston, movable axially in a reciprocating manner in a housing, and an axially movable bit which is connected to an end of the housing and acted upon directly or indirectly by the percussion piston, is of a structure which permits a restoring piston, connected to the bit, to be acted upon by the pneumatic or hydraulic pressure during the return stroke of the percussion piston.

Abstract: A ram boring implement has a pneumatically driven percussion piston (16), which is movable in the axial direction in a reciprocating manner in a housing (12), and a control sleeve (24) which is axially adjustable for reversing the direction of motion of the ram boring implement and is acted upon by the pressure in one (20) of the pressure chambers (18, 20) formed on both sides of the percussion piston (16). The control sleeve (24) can be adjusted by means of a spindle drive (30, 50) by turning a compressed air supply hose (26). According to the invention, the control sleeve is arranged on a core (30, 34), supported in an axially fixed manner on the housing (12), so that the control sleeve itself forms only a relatively small annular effective area (52) acted upon by pressure. This makes it possible for the control sleeve to be moved forward or toward the rear without the compressed air feed having to be interrupted.

Abstract: An earth boring apparatus has a pneumatically operated earth boring tool, a flexible conduit or drill pipe connected to the tool and to a source of pneumatic fluid. The tool has an earth boring member and a reciprocally movable hammer positioned in the tool to apply a percussive force. A valve assembly in the flexible conduit or drill pipe substantially adjacent to the tool between the tool and the source of pneumatic fluid controls the flow of pneumatic fluid to the tool. The valve assembly has a pneumatic pressure-operated valve which is operable in response to the pressure of pneumatic fluid in the flexible conduit or drill pipe to be opened to permit flow of pneumatic fluid to the tool at a predetermined operating pressure to transmit an initial pulse of pneumatic fluid to initiate operation of the hammer. The valve is kept open at a lower pressure than that required to open it.

Abstract: A percussion drilling apparatus has a control unit in which a displacement reversing unit is arranged axially adjacent to a piston control unit, with the result that the control edges for the apparatus advance and apparatus return can be arranged in separate control sleeves. This control unit makes it possible to achieve better apparatus characteristics and higher overall efficiency of the apparatus.

Abstract: A reversible percussion device, having a casing 1 in which is installed a movable striker and a system for distributing fluid under pressure for causing the striker 4 to move for both forward and rearward movement functions of the device. The system comprises a control member 9 for controlling the distribution of fluid under pressure for both functions, which is movably coupled to the striker 4 and has a mechanism for locking it with respect to the casing 1 in two control positions, corresponding to the two functions of the device. According to the invention, the mechanism for locking the control member 9 in the position enabling the forward movement functions of the device comprises a body 11 movable relative to the control member 9.

Abstract: A stake driver having a first rod that has at least one solid end for driving a stake. The other end may be pointed. A second larger diameter rod is slidably insertable over the first rod. One of the open ends of the second rod is located over a stake. Then the first rod is moved upward to allow the stake to be encircled by the open end of the second rod. The end of the second rod may be slotted to accomodate a rectangular stake or marker fastened to the top of the stake. With one hand grasping the second rod, the other hand lifts the first rod and then releases it so that the first rod can free fall and drive the stake into the soil. If additional force is required to drive the pointed end of the first rod into the soil, a third rod is slid onto the second rod and screwably connected to it.

Abstract: A finned impact-operated boring tool according to the invention has an elongated body with a frontally tapered nose which merged with a generally cylindrical housing. A circular array of fins project radially from the housing along the surface thereof rearwardly of the nose of the tool and near the juncture of the nose with the housing. Each fin is generally rectilinear, and the fins are spaced apart to define a series of grooves therebetween which extend in the lengthwise direction of the tool. The distance from the bottoms of these grooves to the lengthwise axis of the tool housing is greater than or equal to the distance from the tool axis to the outer surface of the housing. According to one embodiment of the invention, the fins are formed on a replaceable collar which fits over the node of the tool. The finned boring tool according to the invention has improved movement speed through the ground.

Abstract: An electromagnetic pile driver has an elongated guide in which a magnetic core is permitted to fall by gravity to impact against an anvil transmitting the impact energy to the pile. The core is raised by a coil in a ferromagnetic sheath disposed at an upper portion of the guide and an upper anvil can be provided and coupled to the pile when the apparatus is used for withdrawing piling. The coil is energized by the control discharge of a capacitor.

Abstract: Apparatus for setting bases at selected locations on a baseball or softball field, comprising a base anchor socket or peg member designed to be complementarily engageable with stud members associated with or forming a part of the undersides of bases, a base anchor setting assembly including an elongated shank portion with an associated force transferring portion, which base anchor setting assembly is adapted to be complementarily engageable with the base anchor socket member, and a driving member complementarily engageable with the base anchor setting assembly and operable when so engaged and when the base anchor setting assembly and base anchor socket member are also engaged with one another to effect the repetitive application of force to and through the force transferring portion to cause the base anchor socket member to be driven into the ground at a selected location.

Abstract: The invention relates to the construction equipment. A device comprises a body (1) internally accommodating a percussion member (2) with ports (5), an air distributing sleeve (6), an elastic element (7) and a threaded bushing (8). Grooves (9) are made on an external surface of the threaded bushing (8) at an angle to the axis of the device. When the device is moving soil gets in the grooves (9) of the threaded bushing (8) and develops a circumferential force fixing the threaded bushing (8) relative to the body (1).

Abstract: An air-operated reversible percussive action machine comprises a housing (1) accommodating a reciprocating hammer (2). Secured inside the housing (1) is a stepped tube (5). The step of larger diameter of the tube (5) is received by a cavity (4) of the hammer (2) and has a port (12) for distributing air flow and feeding it to the interior of the housing (1). The tube (5) receives a sleeve (14) having a port (15) alternately communicable with the port (12) of the tube (5) in one of its two positions. One end face of the tube (5) has a projection (13) in the form of a sector of a circle, whereas the sleeve (14) is provided with a radial projection (16) so that in turning the sleeve (14) its projection (16) bears on one of the side walls of the projection (13) of the sleeve (5) thus assuming one of the two positions.

Abstract: A fluid impact tool of the type known as a percussion or rock drill characterized by a percussion mechanism which provides alternative reverse percussion to assist in drill string removal or recovery.

Abstract: A reversible air-operated percussive action machine for driving holes in the ground has a housing accommodating a hammer 2 capable of reciprocating therein. An air distributor 3 is arranged in the hammer 2 in the form of a fixed tube 12 and a valving member 13 movable relative to the tube. Defined between the tube 12 and valviong member 13 is an accumulating chamber 18 which communicates with an air feeding line 4. An air restrictor is further provided for discharging air from the accumulating chamber 18 when the supply of compressed air to the air feeding line is terminated. The valving member 13 spring-loaded relative to the tube 12 by a spring arranged so that during feeding compressed air to the accumulating chamber 18 the valving member 13 is acted upon by a pressure force directed counter to the action of the spring.

Abstract: A double-acting pinch-free impact tool includes an elongated rod supporting a workpiece engaging implement at an inner end and a slam handle at the outer end. An impact sleeve is secured adjacent the outer end of the rod and includes a pair of longitudinally spaced apart annular impact surfaces. The impact producting slam handle is slidably mounted on the rod over the impact sleeve and includes an outer wall surrounding the sleeve and slidable longitudinally relative to the rod. A handle stop sleeve is secured within the outer wall at an inner end of the handle and includes an inner annular stop face adatpted to impact against the adjacent impact surface of the sleeve on the rod when the handle is moved rapidly outwardly. An outer handle stop is secured within the outer wall of the handle adjacent the outer end and includes an inner end stop adapted to impact against the adjacent impact surface of the sleeve and the rod when the handle is moved rapidly inwardly on the rod.

Abstract: Device for withdrawing a pile or the like which has been driven into the soil by a ram device which can perform blows downwardly and upwardly and which in upward direction has a lost-motion connection with the pile, which lost motion for efficient withdrawal is removed by the extension of hydraulic cylinders.

Abstract: A reversible percussive action machine includes a housing accommodating a mmer capable of reciprocating motions under the action of a working fluid under pressure, and a valving member with grooves movably connected to the hammer and provided with members for fixing it relative to the housing in two distribution control positions, particularly one that makes the machine move forward and one that ensures the return travel of the machine. The members for fixing the valving member in a position for the forward travel of the machine is fashioned as an insert movable relative to the valving member and having projections received by the grooves of the valving member. The insert is enclosed by a shell with ports, this shell being secured between the housing and the valving member to be capable of axial displacement.

Abstract: A percussive tool comprises a percussion mechanism and a pressure pulser. The percussion mechanism has a hollow housing with a piston hammer arranged thereinside to form two chambers of variable volume. The pressure pulser has a hollow housing and a fluid displacer defining inside the housing a working chamber adapted to alternately communicate with a source of gaseous fluid and the interior of the percussion mechanism. The fluid displacer is intended for forced displacement inside the housing to transmit to the chambers of the percussion mechanism a pulsed pressure of the gaseous fluid which causes the piston hammer to reciprocate. The interior of the percussion mechanism is isolated from the outside, whereas the working chamber of the pressure pulser communicates with at least one of the chambers of the percussion mechanism, the chambers of the percussion mechanism continuously intercommunicating by way of a restrictor passage.

Abstract: An air-operated reversible percussive action machine comprises a housing in which there is disposed for axial reciprocations a hammer, defining therewith a front working chamber and having a through radial passage. In the axial interior of the hammer on the side of its tail end there is provided a cylindrical stepped tube including coaxially arranged first and second steps of large and small diameters, respectively, these steps having through radial passages. The first step of the tube defines with the hammer a rear working chamber, and with the second step defines an annular cavity in which a spring sleeve capable of axial displacements is disposed. The outer diameter of the sleeve is substantially less than the inner diameter of the first step of the tube to form an annular passage there between. The machine is further provided with a means for pressure-sealing the annular cavity and a means for controlling the displacements of the sleeve.

Abstract: A portable hand held post driver which is fully operable by a single worker and which uses a fluid powered cylinder to drive posts into the ground. The cylinder raises a balanced driving weight and forces the weight down onto the post. The cylinder is reversed automatically at both the top and bottom of its stroke to automatically repeat the driving strokes so long as a hand lever is held by the operator. The post is clamped to the frame of the implement by a clamp having an overcenter control linkage. Before the implement can be operated, a safety linking pin must be intentionally released by operating a safety lever.

Abstract: A reversible pneumatic underground piercing tool of the type having a reciprocating striker with the impact of the striker on the front or the rear of the tool being controlled by the longitudinal position of a valve element in the tool. An interengaging pin and slot arrangement in the tool defines the longitudinal the valve element which is positively maintained in the selected position by the supplied air pressure. The longitudinal position of the valve element may be changed for reversing the direction of movement of the tool by interrupting the compressed air supply and rotating the air supply hose a small amount in one direction or the other to reposition the pin in the slot.

Abstract: Stuck well pipe is removed from a well bore by applying an upward pull to the stuck pipe while applying an upward jarring action to the pipe by an air hammer which applies rapid blows to a linkage mechanism connected to the pipe.

Abstract: A driving and extracting apparatus has a hammer frame within which a reaction mass is freely movable. The reaction mass is caused to reciprocate within the hammer frame by the selective application of drive pressure to opposite drive cylinders at a frequency corresponding to the natural frequency of the mass. A pneumatic spring at each end of the reaction mass prevents contact between the reaction mass and the ends of the hammer frame. Sensors in the hammer frame detect the position of the reaction mass and adjust the pneumatic springs accordingly.

Abstract: Apparatus for use in the laying and/or replacement of pipes under ground comprises a casing (1), a frusto-conical impact member (2) secured to one end of the casing and adapted to form an underground passage for the casing when the apparatus is being driven through the ground, a piston (7) reciprocally mounted in the casing and arranged to be driven by a source of compressed air or other fluid to engage the impact member (2) with a series of impacts to drive said member and the casing through the ground and a control valve member (11) adapted to be connected to a source of compressed air or other fluid and arranged to reciprocate the piston in the casing by means of said compressed air or other fluid. A pipe fitting (31) is connected to a tubular spacer member (23) which is mounted on the other end of the casing (1), said pipe fitting being adapted to be clamped to the leading end of a pipeline (29 and/or 30) which is to be laid in the underground passage formed by the impact member (2).

Abstract: A steering system is disclosed for percussion boring tools for boring in the earth at an angle or in a generally horizontal direction. The steering mechanism comprises a slanted-face nose member attached to the anvil of the tool to produce a turning force on the tool and movable tail fins incorporated into the trailing end of the tool which are adapted to be selectively positioned relative to the body of the tool to negate the turning force. The fins are constructed to assume a neutral position relative to the housing of the tool when the tool is allowed to turn and to assume a spin inducing position relative to the housing of the tool to cause it to rotate when the tool is to move in a straight direction. Turning force may also be imparted to the tool by an eccentric hammer which delivers an off-axis impact to the tool anvil. For straight boring, the tail fins are fixed to induce spin of the tool about its longitudinal axis to compensate for the turning effect of the slanted nose member or eccentric hammer.

Abstract: A reversible percussive action machine comprises a housing which accommods a hammer capable of reciprocating motions under the action of a pressurized fluid, and a fluid valving member for controlling the distribution of fluid with parts for fixing it in two fluid control positions to assure either the forward or rearward percussive action of the machine. To fix the fluid valving member to provide for the forward percussive action of the machine, a spring-loaded insert which is movably secured relative to the valving member and engageable with a stop made in the housing is used. To fix the fluid valving member in a position to provide for the rearward percussive action of the machine, a stop made on the inside wall of the housing and a stop made in the valving member to engage with the stop of the housing is used. The insert is fashioned as a cup accommodating an element imparting a spring action on the cup relative to the fluid valving member.

Abstract: A pneumatically operated impact-action self-propelled mechanism for driving holes in the earth is disclosed. The mechanism comprises a cylindrical housing with an anvil member located at the forward end thereof. An impact piston is reciprocal in the housing to deliver successive impacts to the anvil member and shapes with the housing a forward chamber of variable volume. A control assembly comprises a forwardly extending sleeve which is slidably received within a rear space of the impact piston to form a rear chamber of variable volume. A central passage is connected to the sleeve for continuous supply of compressed air into the rear chamber and therefrom into the forward chamber through apertures in a side wall of the rear chamber of the impact piston. An arrangement is provided for lockably locating the sleeve longitudinally with respect to the apertures for providing forward or reverse movement of the mechanism.

Abstract: A burrowing tool having a pneumatically reciprocable piston hammer concentrically slidable about an adjustable valve sleeve, wherein the valve sleeve may be positioned to cause the piston hammer to impact against either a forward or a rearward anvil, with position mechanism including a threaded and slotted reversing screw removably fitted into the rearward end cap of the tool, the slotted portions of the reversing screw serving as a plurality of exhaust ports, wherein the end cap is sized to permit removal of the valve and inner mechanism upon removal of the reversing screw from the tool.

Abstract: A hydraulically operated self-propelled subsoil penetrating tool of the type including an elongated housing member having a penetrating nose with a forward anvil surface, the forward anvil surface defining one end of a cylindrical cavity, a rear anvil surface defines the other end of said cavity, a hammer is slideably mounted in the cavity and has impacting surfaces at either end thereof adapted to impact on the anvil surfaces, the direction of travel of the tool is being determined by the anvil upon which said hammer impacts, the hammer is slideably in said cylindrical cavity to selectively impact upon one of said anvil surfaces and has internal bores of different diameters defining forward and reverse piston surfaces, the forward piston surface area being greater than the reverse piston surface area, a valving member is slideable in one of the hammer bores between the forward and reverse piston surfaces and defines forward and rear variable volume fluid chambers.

Abstract: A compact and portable pulling apparatus is disclosed. The apparatus includes a housing having a bore therein through which a plunger attached to a reciprocating bit of an attached air chisel may pass. Pivotally attached to the housing is a compact linkage mechanism which preferably has only two pairs of link elements. One end of the linkage mechanism is positioned to abut an end portion of the plunger and an opposite end is attached to a connecting yoke whereby an outward thrust of the air chisel bit causes the connecting yoke to be pulled inwardly. The connecting yoke is designed to attach any one of a number of various gripping or holding mechanisms to the pulling apparatus which may be required for any particular application. A method of applying a pulling force to an object is also disclosed.