Abstract: An impact breaker has a sleeve which slidably receives an end portion of a tool. The tool is formed over its end portion with a groove extending completely around the end portion of the tool for receiving lubricant for lubricating movement of the tool in the sleeve.

Abstract: A percussive hammer for delivering impacts driven by oil which is quickly applied under pressure derived from a system supply and from a source of compressed gas.

Abstract: A hammer holder, provided between a retainer sleeve and a cylinder, slidably holds an intermediate member in an axial direction. A predetermined clearance is maintained between the hammer holder and the retainer sleeve. The hammer holder has a recessed portion which is engageable with a flange of the intermediate member so as to restrict the slide movement of the intermediate member. A cushioning member receives a percussion force when the flange is stopped by the recessed portion. The clearance restricts a compression amount of the cushioning member so that a predetermined life of the cushioning member is assured.

Abstract: A improved apparatus for decelerating a piston and impacting rod assembly within a single stroke foundry impactor utilizing a non-metallic deceleration piston slidably positioned within a pressurized deceleration chamber mounted proximate the end of the bore containing the impactor piston and impacting rod assembly. The deceleration piston is biased towards the impactor bore by pressurization of the deceleration chamber, such that upon a stroke of the impactor, the residual kinetic energy of the piston and impacting rod assembly is absorbed by the biased deceleration piston.

Abstract: An impact hammer having a non-mechanical connection between the driving piston rod and the impact ram. The non-mechanical connection includes an annular body portion connected to the lower end of the piston rod which is received in a cavity in the top surface of the impact ram, and an elastomeric ring is held in facing grooves in the cavity and the annular body member to constitute the sole connecting element between the piston rod and the impact ram.

Abstract: A power assisted roofing shovel for removing shingles and attached nails from a roof to facilitate re-roofing. The shovel comprises a handle, a shovel blade, a trigger mechanism, and a mechanism for reciprocating the shovel blade. The mechanism for reciprocating the shovel blade may be an air hammer, an electric motor, a solenoid, or other power assisted device. The handle is an elongate hollow cylinder having the trigger mechanism attached to its rearward end, the shovel blade attached to its forward end, and a reciprocating mechanism there between. The shovel blade has a generally flat leading edge adapted for removing roofing materials and a rearward shank. A bracket member, extending rearward from the shovel blade, is adapted to slidably connect the shovel blade and the handle for reciprocal movement of the shovel blade.

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

Abstract: A multi-purpose impact tool, i.e. a tool for splitting wood or bricks, tamping, scraping ice of cutting trenches includes an elongated guide bar with a threaded bottom end for carrying an appropriate head, a sleeve slidably mounted on the bar for reciprocating against the head for driving the latter, and a cam lock near the top end of the sleeve locking the guide bar and sleeve together in a non-use position.

Abstract: The most dangerous task in mechanically driving a post into the ground is initially holding the post in an upright position while it is hammered to start it into the ground. When used with mobile equipment having an hydraulically driven post pounder the post picker not only eliminates the danger in starting a post into the ground, but additionally eliminates the necessity of using more than one man to do the job! A method is disclosed wherein a single hydraulic valve on a piece of mobile equipment may be used to control both the post picker and pounder.

Abstract: Disclosed is a reciprocating pneumatic tool that includes a retainer mechanism for preventing the piston from freely exiting the barrel of the tool when the retaining sleeve and workpiece are removed. The retainer mechanism does not interfere with the functional operation of the tool when the workpiece and sleeve are attached to the tool. The retainer mechanism is mounted distally around the butt of the workpiece such that no contact occurs with the retainer mechanism or the piston.

Abstract: A device for transmitting pulsed axial percussions to a drill (12) and including a housing (2) one end of which is releasably connectable with a housing (3) of a hand-held rotary drill, a rotation transmitting element (7, 9) rotatably supported within the housing (2) and operatively connected with a rotatable spindle (4), which projects from the rotary drill housing (3), for joint rotation therewith, a chuck (11) provided at an end of the device housing (2) opposite to the one end for receiving the drill (12), a reciprocating hammer member (15) movable into an abutting engagement with a trailing end of the drill (12), and a hammer mechanism (17-20; 21-24) arranged within the device housing (2) for imparting pulsed axial percussions to the hammer member (15) and connected with the rotation transmitting element (7, 9) for generating the pulsed axial percussions.

Abstract: A hydraulic ramming apparatus including an apparatus body (14) having a cylinder bore (23) and a guide bore (24) that are successively formed to each other in the apparatus body (14). A piston (30) is slidably inserted into the cylinder bore (23) so as to be reciprocable within the cylinder bore (23). An upper pressure-receiving chamber (31) is defined at an upper end portion side of the piston (30), and a lower pressure-receiving chamber (32) is defined at a lower end portion side of the piston (30). A ramming tool (19), having a rod body (35), can be detachably inserted into the guide bore (24). Also, a mechanism for moving the rod body (35) is provided so as to follow upward movement of the piston (30).

Abstract: Disclosed is an improved forcible entry tool for opening locked or jammed doors by emergency personnel for the purpose of apprehending criminal suspects, gathering evidence, and preserving lives of people who become trapped by fire, earthquake, tornadoes, or by other circumstances beyond their control. The tool of the present invention comprises an elongated frame with a piercing pivot blade on the front end of the tool. The pivot blade is configured to pivot perpendicular to the frame upon penetration through a door, thereby enabling the tool operator to effectively pull back on the tool to break open an outwardly swinging door. A detachable ram head may be mounted over the front end of the frame for purposes of breaking through a door that swings inward (i.e. away from the tool operating personnel).

Abstract: A pneumatic impact breaker comprises a housing (11) with a cylinder bore (20), a hammer piston (28) with a piston head (63) and an impact delivering stem portion (64), an anvil (14) displaceably supported in a cylinder bore extension (50) and normally abutting against the shank (15) of a working implement (16), an annular energy absorbing air cushion chamber (59) is formed between the hammer piston (28), the cylinder bore (20) and an annular shoulder (49) in the cylinder bore (20), wherein the piston head (63) is formed with two axially spaced end portions (65, 66) for guiding and sealing cooperation with the cylinder bore (20).

Abstract: A pneumatic portable impact tool includes a tubular housing, at least one handle pivotally supported on the housing, a hammer piston formed with an impact delivering neck portion, and an air distribution valve for directing air pressure alternatingly to opposite ends of the hammer piston so as to make the hammer piston reciprocate in the housing. The housing includes a rear section, an intermediate section, and a front section integrally formed in one piece. The rear section includes a socket portion for supporting the air distribution valve. The intermediate section includes a cylinder bore for sealingly guiding the hammer piston, and a damping sleeve mounted in the cylinder bore and arranged to be penetrated by the hammer piston neck portion, thereby forming a hammer piston damping air cushion chamber. And the front section includes a working implement receiving front opening and supports a movable latch arranged to releasably lock a working implement to the housing.

Abstract: An air pressure actuated shovel for removing shingles and attached nails from a roof to facilitate re-roofing. The shovel has an elongated handle with a finger actuated trigger mechanism attached to its top end and a shovel blade supporting an air hammer attached to its bottom. The trigger connects the air hammer and an external pneumatic power source via an air hose inside the handle so that when the trigger mechanism is squeezed, a reciprocating piston, driven by an air hammer, abuts the shovel blade to cause it to vibrate. The vibrating shovel blade effectively loosens shingles and nails from the roof of a building. The removal of shingles with the associated nails intact enhances safety due to the elimination of flying nails.

Abstract: Disclosed is a reciprocating pneumatic tool that includes a retainer mechanism for preventing the piston from freely exiting the barrel of the tool when the retaining sleeve and workpiece are removed. The retainer mechanism does not interfere with the functional operation of the tool when the workpiece and sleeve are attached to the tool. The retainer mechanism is mounted distally around the butt of the workpiece such that no contact occurs with the retainer mechanism or the piston.

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

Abstract: A hydraulic breaking hammer having a machine housing including a cylinder bore and an impact piston which is reciprocatingly movable in the cylinder bore in response to an alternating hydraulic pressure, and a tool part having: (i) a head portion fitted to a front portion of the machine housing, and (ii) a guide bore which lies in line with the cylinder bore and in which a breaking tool is slidably carried and repeatedly subjected to impact by the impact piston. A seal is arranged at the front portion of the machine housing between the cylinder bore and the impact piston for separating drive hydraulics of the breaking hammer from the tool part, and a transverse slot is formed in the front portion of the machine housing between mutually opposing side wall portions of the machine housing so as to intersect the cylinder bore forwardly of the seal.

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

Abstract: A portable power driven post driver. The post driver has an inner hollow cylinder open at its upper end and adapted to receive a post through a locking mechanism located at its lower end. The inner cylinder is located within an outer hollow cylinder in sliding engagement therewith, the outer cylinder having a closed upper end in contact with the upper end of a post held in said inner cylinder. Two fluid powered cylinders and associated pistons are attached to the outer surface of the outer cylinder, the longitudinal axes of the two fluid powered cylinders being in alignment. A common piston rod extends between the two pistons and is attached by a fastening member to the inner cylinder, the fastening member extending through a slot in the outer cylinder.

Abstract: The disclosure relates to an improved manual stake-driving land anchoring device characterized by a slidable cylinder disposed within very close tolerances around an impact head on a stake, and oppositely disposed, angularly adjustable and removable handle assemblies mounted on an outside wall of the cylinder, whereby the stake may be driven comfortably into and out of a hard substrate, whereby a tethering line may be attached to the handle assembies, and storability of the device is enhanced by the removal or rotation of the handles to a more convenient position.

Abstract: A manually operable tool, such as a hammer drill, for drilling and/or removing material in at least one of brittle material and low ductile material, has a continuously rotatable chuck (8) and a motor driven striking mechanism (1) for transmitting impulse-like blows to a tool bit (9) held in the chuck (8). The tool includes members (5) for transmitting impulse-like blows composed of superimposed axially-directed blows and torsional blows to the tool bit (9) in the chuck for forming drilling blows. Further, an adaptor can be provided for attachment to the hammer drill containing the members (5) for affording the superimposed blows.

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: There is provided an improved abrasion-resistant hydraulic hammer with a low noise level for preventing the leak-out of the noise made inside. The object is to provide an abrasion-resistant hydraulic hammer with a low noise level which can contribute to the establishment of a comfortable working environment and meet environmental standards against noise pollution by reducing leaked-out crashing sound. To achieve the object, a cylindrical plastic member containing oil is installed to a hole formed outward under a piston installed inside the hydraulic hammer, for guiding a tool in contact with the circumferential surface thereof.

Abstract: A pneumatic impact breaker includes a housing provided at a rear end thereof with at least one handle, a longitudinal cylinder bore formed in the housing, and a hammer piston reciprocally guided in the cylinder bore. A socket is formed in a front portion of the housing for receiving a rear impact receiving end of a working implement. An air distributing valve is located in a rear portion of the cylinder bore and arranged to direct motive pressure air alternatingly to opposite ends of the hammer piston to make the hammer piston reciprocate in the cylinder bore. And a cylinder head forms a closure for the cylinder bore as well as an axial support for the air distributing valve. The cylinder head at least partly extends into the rear portion of the cylinder bore, the housing is formed at the rear end thereof with two parallel wall portions both extending rearwardly beyond the cylinder head, and the at least one handle extends in between the two parallel wall portions.

Abstract: An improved pile driving drop hammer of the free piston internal combustion engine type preferably has integral pistons on each end of a ram that reciprocates, usually vertically, in an enclosing bore. There is a combustion chamber on each end of the bore and exhaust ports situated near each combustion chamber such that the ports are opened, two cycle engine fashion, by the associated piston, after some movement of the piston, after combustion takes place to vent the active combustion chamber and then serve as intake ports when the piston moves some distance farther along the bore. At each end of the bore an anvil extends from the bore, axially movable some amount, to serve as an end to each combustion chamber. The lower anvil delivers ram impact energy to the driven piling and the upper anvil delivers impact energy from the ram to a free rising mass that is the essential element of this invention as an improvement to existing hammer designs.

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

Abstract: An elongated stake having a sharply pointed lower end and a polygonal shaped upper end. A hammer is slidably mounted on the stake and is limited in its travel by an upper abutment located at the upper end and a lower abutment located about midway between the upper end and the lower end. Mounted at the upper end is a first tie down ring with a second tie down ring being mounted at the lower abutment with these tie down rings facing in opposite directions. Repeatedly impactingly moving of the hammer against the lower abutment will result in the lower end of the stake to be driven into a supporting surface. A resilient cover is mounted about the hammer which includes a strap to enclose the user's hand preventing injury to the user during hammer usage. A separate tent stake is to be engageable with the upper end and repeated impacting movements of the hammer against the upper abutment is to result in driving of the tent stake into a supporting surface.

Abstract: A pile hammer for driving down hollow piles from an upper end thereof includes a hollow pile cap adapted to rest and support the hammer on a upper end of the pile being driven. The cap has an anvil surface for receiving blows from a ram which is slidably disposed on a hollow tubular base extending downwardly from the pile cap and having a lower end portion extending into the hollow pile being driven below the level of the pile cap. The ram is slidable on an upper portion of the hollow tubular base and has an annular lower end face adapted to strike the anvil surface of the pile cap when the ram is released to drop from an elevated position above the pile cap. A ram lift system is provided in an upper portion of the hollow tubular base for lifting the ram to an elevated position a selected predetermined height above the pile for release to drop downwardly and strike a driving blow against the anvil surface on the pile cap.

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 handheld pneumatic power tool apparatus is provided for use with a supply of pressurized air. The apparatus includes a handpiece and a pressure regulator assembly for regulating the pressure of air supplied to the handpiece. The handpiece includes a cylinder having first and second ends, an anvil positioned at the first end of the cylinder, and a piston received in the cylinder for bi-directional oscillating movement between the ends.

Abstract: A rotary impacting apparatus comprises a housing, a rotor rotated in the housing, an impact member eccentrically held by the rotor, and a main reciprocative implement held reciprocatively at a forward end portion of the housing. The rotor rotates to hit the impact member for driving the main reciprocative implement into the ground for instance. The apparatus further includes an auxiliary oscillating mechanism for transmitting an impacting force from the impact member to pull the main reciprocative implement when the housing is pulled relative to the main reciprocative implement by a predetermined distance.

Abstract: A pneumatic ground piercing tool has a head which can be removed and replaced with a replacement head of the same or different design. The detachable head is mounted on the an axial rod behind a threaded surface of the rod, and a nut is threadedly secured on the front threaded portion of the rod, whereby the head is clamped between a front end of the tool housing and the nut. The nut can be unscrewed from the rod to permit replacement of the head. A clamp-loading locking mechanism is used to secure the head to the nut to prevent the nut and head from loosening during operation.

Abstract: A handheld paving breaker includes a reciprocal chuck in a front head and an elastic spring for biasing the chuck toward the fronthead. The chuck can move longitudinally, but is restrained from rotation in the fronthead. A moil mounted in the chuck is biased against the work surface by the chuck, to provide better control of the moil, during start-up and operation. Wear pads between the spring and members against which the spring is seated improve spring life.

Abstract: A method for adjusting the impact force on a hammer operated by a compressible pressure medium utilizes a hammer including a working cylinder having a to-and-fro moving percussion piston and a spindle positioned therein for striking a tool. The working cylinder is positioned inside an outer shell and the spindle is attached to the outer shell. The working cylinder is movable relative to the outer shell and the spindle. A pressure chamber is formed between the working cylinder and the outer shell and pressure medium is fed into or removed from the chamber to adjust the position of the working cylinder relative to the outer shell. In making this adjustment, the strength and frequency of impact of the piston against the opposite end of the spindle is adjusted.

Abstract: A pile driving apparatus and method includes a hammer assembly having a guide member extending therefrom. The guide member is engageable with the pile, and the hammer is connected to the end of a crane line or the like. A retainer chain is interconnected between the hammer and the pile. The hammer is lifted and lowered in response to operation of the crane, and the retainer chain functions to maintain the guide member in engagement with the pile during upward movement of the hammer. The pile thus functions to guide upward and downward movement of the hammer as it is raised and lowered in response to operation of the crane.

Abstract: Down-the-hole drilling machine comprising a housing in form of a tube (1), a hammer piston (6) being movable to-and-fro in the tube and intended for impacting a drill bit (5). The hammer piston is at its ends provided with end sections in form of polygons with rounded corners (51, 52). These end sections are turned relative to each other an angle which is half as large as the angle between two adjacent corners.

Abstract: A percussion drilling apparatus having an outer casing, a fluted inner sleeve affixed to the outer casing, a hammer piston having a longitudinal opening therethrough adapted to fit around extensions of a cyclic valve positioned at the top of the inner casing, and a foot valve mounted atop a drilling bit at the bottom of the apparatus. An air channel positioned between the inner sleeve and outer casing is adapted to cooperate with channels on a reciprocating hammer piston to alternately drive the hammer piston up and down.

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: A first rotation driving mechanism including a hydraulic motor (26), a driving gear (27), and a driven gear (29) is provided between a coupling arm unit (12) attachable to the operational arm of a construction machine such as a hydraulic shovel, etc., and a hanger unit (14) to relatively rotate them in the horizontal plane, and at the same time, a second rotation driving mechanism including a hydraulic cylinder (32) and a rocking arm (34) is provided between the hanger unit (14) and a main body (20) to rotate them in the vertical plane. The positional changes of the hanger unit (14) and the main body (20) are automatically performed by a remote control rapidly and easily, and further, with safety to improve the mobility and operativity of the piling, and the pile installation and removal.

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: 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: The present invention comprises an electrical grounding rod driving tool for use with an externally powered hammer comprising a shaft portion for insertion into a tool receiving chuck of the hammer and a base portion extending outwardly from said shaft portion which receives and retains the end of a grounding rod to which the powered hammer is applied. The base portion comprising an inwardly extending elongated tapering bore from the exterior end of said base portion which bore is identified as a conical bore, the interior terminus of said bore being truncated and terminating in a concave cap, the outer circumference of which is in tangential relationship with the walls of said inwardly extending conical bore. The diameter of said bore at said exterior is greater than the original exterior diameter of the rod to be driven, the diameter of said bore at the truncated terminus being less than the original diameter of said rod.

Abstract: The present invention relates to a tool and method of using the same for pushing or pressing rods into the earth. A moveable pusher body is mounted on an elongated, slotted mast, and is provided with several pivotal pusher plates which are implemented one at a time so as to press a rod into the ground, in incremental fashion, under the force of a downward stroke from a prime mover. A coupling tool may also be provided so that several lengths of rods can be inserted into the ground.

Abstract: The hydraulic jackhammer is provided with a rotor turbine which is driven by a liquid stream in order to activate the tup for driving against a jumper rod. After passing by the turbine rotor, the liquid stream is mixed with air and passed through a nozzle into a guide channel under pressure in order to cool the casing. Some of the liquid-air mixture is passed through the hollow jumper rod for spraying onto a jumper bit and sprayed onto the rock being drilled.

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 driving-in pipes by means of a connecting piece engaging in the rear end of the pipe and a rammer engaging in the connecting piece, flanging of the back end of the pipe can be prevented by forming the connecting piece as an expanding ring having a cylindrical outer face and an inner cone.

Abstract: A relatively simple pile driver includes a tubular holder with a closed top end and an open bottom end for receiving a pile; a tubular hammer with a closed bottom end and an open top end, the hammer containing lead and being mounted on the holder; four guide rods extending through large plates closing the top end of the holder and the bottom end of the hammer permitting controlled vertical movement of the hammer above the holder, the guide rods extending upwardly to a positioning plate above the hammer; a pair of cables extending upwardly from the plate closing the top end of the holder and through slots in the positioning plate to a bar, which is connected to a crane or other lifting apparatus by another cable for positioning the pile drive; and a pair of hydraulic cylinders extending upwardly from a pair of brackets on the bottom end of the holder, with piston rods extending upwardly from the open top ends of the cylinders to brackets on the hammer above the holder, whereby, the hammer can be raised and, wh