Abstract: A pile driver comprises a hammer for impacting a pile, a velocity sensor for measuring the velocity at impact, and a control system for adjusting the hammer stroke in accordance with the readings from the velocity sensor so that the optimal impact energy is imparted to the head of the pile. Optionally, the system further comprises a pile driving analyzer (including at least one strain gauge and/or an accelerometer) mounted on the side of the pile itself to determine whether the impact loading on the pile is below the maximum allowable stress. If the pile driving analyzer senses an overload of stress on the pile, the control system will reduce the velocity of the subsequent hammer stroke so that it no longer exceeds the maximum allowable stress.

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

Abstract: A hydraulic hammer having a sealing bushing includes a percussion piston that delivers strokes to a tool. A lower part of the percussion piston is sealed with respect to a frame by the sealing bushing, which includes one or more lower seals. The sealing bushing does not contribute to the bearing of the percussion piston and it is arranged in place through the lower end of the hydraulic hammer.

Abstract: A method of inserting a grounding rod includes providing an elongated grounding rod that has an upper end and a lower end and also providing a hammer drill. An elongated tubular member has an open first end and an open second end. The tubular member includes a first portion and a second portion. A dividing wall is integrally attached to an inner surface of the tubular member and is positioned at a juncture of the first and second portions. Te upper end of the grounding rod is extended into the second portion of the tubular member such that the upper end abuts the dividing wall. The hammer drill is engaged with the first portion of the tubular member. The hammer drill is turned on so that the lower end of the grounding rod is extended into a ground surface.

Abstract: A post driving device is disclosed. The post driving device slides to a desired position and is essentially locked in place through frictional force. As the post is driven into the ground, the device can be adjusted to a new position along the length of the post.

Abstract: Battery-powered tools may include battery 1 or battery pack BP and a drive source (e.g., motor M) for generating power using current supplied from the battery. A switch 3 may electrically connect the battery to the drive source. A voltage detector may detect the output battery voltage of the battery. Further, a processor 60, 210, a comparator 5 or another similar device preferably determines when a difference between (1) a first battery voltage detected at a first predetermined time period after the switch is turned OFF and (2) a second battery voltage detected at a second predetermined time after the first predetermined time period exceeds a predetermined value. This information may be utilized to determine whether to warn an operator of the battery powered tool that further operation using the battery 1 or battery pack BP should be discontinued.

Abstract: A pile driving device for driving in piles, with an axially-guided impact body movable in a hammer housing, an impact hood and a pile sleeve. So that the pile driving device can be transported by land without requiring surveys and preparation, the pile sleeve comprises two or more parts, with the pile sleeve being divided into radial or circular concentric partitions.

Abstract: Power tools of the type under consideration include hammer drills, for example, which are electric or battery powered and includes two modes of operation: a rotation mode and a rotation-hammer mode. A manually operable selector lever enables the hammer drill to be selectively operated in one of the two modes by disengaging and engaging a hammer mechanism. In rotation-hammer mode, the drive shaft of the hammer drill rotates a tool element about a rotational axis and oscillates the tool element along a rotational axis. An attachment mountable within the chuck of a hammer drill prevents a tool element from rotating when the hammer drill is operating in rotation-hammer mode. The hammer drill attachment transfers hammer action, but not rotation, to the tool element. The hammer drill attachment enables dual function power tools to be operated in a hammer only mode to perform a function, for example, chiseling.

Abstract: An electric power tool includes a housing, an inner case and a hammer case. The housing receiving a motor has a pair of half portions. The inner case receives a planetary gear train. An input side of the planetary gear train is connected to a drive shaft of the motor. The housing receives the inner case. The hammer case receives a hammer unit. An input side of the hammer unit is connected to an output shaft of the planetary gear train to convert rotation of the output shaft of the planetary gear train into an intermittent striking power outputted from an output shaft of the hammer unit. The hammer case receives the inner case having recesses. The hammer case has elongated holes aligned with the recesses. Each half portion has bosses engaging with the elongated holes of the hammer case, which are aligned with the recesses of the inner case.

Abstract: It is an object of the present invention to provide a reciprocating power tool having a further improved power transmission mechanism for converting a rotating output of a driving motor into linear motion in the axial direction of the tool bit. According to the present invention, a representative reciprocating power tool may comprise a tool bit, a driving motor, a power transmission mechanism. The power transmission mechanism converts a rotating output of the driving motor into linear motion in the axial direction of the tool bit. The power transmission mechanism includes an internal gear, a planetary gear and a power transmission pin. The internal gear is allowed to rotate by a predetermined degree in relation to a load applied to the tool bit. As the result of rotation of the internal gear, the relative position of the power transmission pin is changed with respect to the point of engagement between the internal gear and the planetary gear.

Abstract: An apparatus for rotating a threaded tightening device includes a guide and an anvil utilized to impact a lug on the threaded tightening device to rotate the tightening device onto or off of a threaded member. The guide has a frame with a support sleeve attached thereto. A reciprocating device is received in and is supported by the support sleeve. The anvil is attached to the reciprocating device. When the reciprocating device is received in and is supported by the support sleeve, actuation of the reciprocating device will cause the anvil to repeatedly impact a lug to rotate the threaded tightening device in the desired direction.

Abstract: An impactor for use with a directional boring machine for replacement of underground pipes includes a bursting head having a rearwardly opening recess and a front end opening that communicates with the recess. An inlet pipe is connected at its front end to a distal end of the drill string and extends into the recess of the bursting head through the front end opening. A striker is mounted for sliding movement along the inlet pipe, and a distributing mechanism responsive to pressure fluid supplied through the drill string and inlet pipe causes the striker to reciprocate in the rearwardly opening recess of the head to deliver forward impacts against the bursting head. The striker and distributing mechanism are mounted in a tubular housing, and a pulling connection is provided by which the impactor can be pulled by the drill string while the striker is delivering impacts against the head in the same direction as a pulling force exerted by the drill string.

Abstract: A fastener installation tool to install fasteners, such as rivets, risers, standoffs, and other types of fasteners operates upon vacuum and air pressure. Fasteners are installed with minimal reactive forces to the operator's hand, thus reducing the risk of repetitive injuries to the operator's body. Vacuum retains the fastener within the tool tip and retracts a piston, until an operator simultaneously presses the fastener against a work piece and actuates an actuation element on the tool. This causes air pressure to quickly thrust the piston against a hammer pin to drive in the fastener, transferring kinetic energy from the piston to the fastener without appreciable kick-back to the operator. A control system provides a source of vacuum and air pressure to the tool. Methods of using a fastener installation tool are also described.

Abstract: A hand power tool has a housing (10), a hammer barrel (12), a tool receptacle (14) that is separated from the hammer barrel (12) at least one locking body (16) for fixing the tool receptacle (14) in a direction of rotation (18), a transmission unit (20) arranged radially outwardly of the tool receptacle (14) for transmitting a torque from the tool receptacle (14) radially outwardly and fixing the tool receptacle (14) in the direction of rotation (18) of the tool receptacle (14) on the housing (10), one part of the transmission unit (20) being formed by an actuating sleeve (28), the transmission unit (20) having a claw ring (30) which is separate from the actuating sleeve (28) and the tool receptacle (14) being connected through the claw ring (30) with the actuating sleeve (28) in the direction of rotation (18).

Abstract: A double-headed tent stake driver and puller is provided for inserting and removing tent stakes, nails and the like. The double-headed tent stake driver and puller includes a slide hammer and a coupler mounted on the distal end of the slide hammer shaft. The coupler has an elongate body with an open end and a hollow core sized to receive the head of the stake or nail intended for use with the present invention. The coupler includes a retractable keeper slidably received within. The keeper provides the twofold benefits of retaining the stake once inserted into the coupler, and presenting a surface for imparting the extraction force upon a stake to be pulled from the ground. The keeper is urged to its closed position by a spring.

Abstract: A hand power tool has a tool, a hammer tube, a striking mechanism with a striker and an anvil with an integrated receptacle for the tool which is strikingly drivable in the receptacle, a blocking element connecting the tool and the anvil in an axial direction, and a toothing that connects the anvil with the hammer tube displaceably in an axial direction.

Abstract: An impactor for use with a directional boring machine for replacement of underground pipes includes a bursting head having a rearwardly opening recess and a front end opening that communicates with the recess. An inlet pipe is connected at its front end to a distal end of the drill string and extends into the recess of the bursting head through the front end opening. A striker is mounted for sliding movement along the inlet pipe, and a distributing mechanism responsive to pressure fluid supplied through the drill string and inlet pipe causes the striker to reciprocate in the rearwardly opening recess of the head to deliver forward impacts against the bursting head. The striker and distributing mechanism are mounted in a tubular housing, and a pulling connection is provided by which the impactor can be pulled by the drill string while the striker is delivering impacts against the head in the same direction as a pulling force exerted by the drill string.

Abstract: A pneumatic linerbolt removing tool including a moil supported for reciprocal movement along a hammer axis within a housing, an inertial body movably mounted along the hammer axis, and a piston assembly moveable within the inertial body along the hammer axis between a striking position at which it strikes the moil and a retracted position remote therefrom. The tool further including a gas-charged accumulator for urging the piston toward the moil and air supply to a cylinder adapted to urge a biasing piston on the inertial body relative to the housing and toward the moil. The inertial body being ported so that working air is supplied to a front face of the piston assembly to urge it to a coked position away from the moil and whereby the accumulator is in its compressed state, and selectively operable porting for equalizing pressure between the front and rear faces of the piston, to continuously allow transfer of air between the faces while in operation.

Abstract: An electrical hand held tool for producing at least a percussion movement of a working tool includes an electrical drive, a first, oscillating subassembly including a percussion mechanism (2) and a rotor (5) of the electrical drive for transmitting torque to the percussion mechanism and rotatable about a rotor axis (B) extending parallel to an oscillation path (I) of the first subassembly, and a second subassembly including a housing (6) in which the first subassembly is supported for a limited oscillating movement along a tool axis (A).

Abstract: A rock drilling machine has a housing (1), a hammer piston (2) movable to-and-fro in the housing, a drilling tool (3), and a guide (4) for the drilling tool. The guide (4) consists at the surface against the drilling tool (3) of polyethyleneterephthalate.

Abstract: An impact tool enables a front cover part to be easily attached to and detached from a housing body, with a device having a simplified structure. The front cover part has an annular fastening portion clamped to the outer peripheral surface of a front edge portion of the housing body, a cylindrical portion extending from the front end of the housing to the region of the fastening portion, and a connecting portion connecting together the cylindrical portion and the fastening portion. The fastening portion is split at a circumferential part thereof to form a pair of circumferentially opposing tongue-shaped portions. A clamping device is provided between the tongue-shaped portions, which is movable between a clamping position where it pulls the tongue-shaped portions toward each other and an unclamping position where the tongue-shaped portions are released from being pulled toward each other.

Abstract: Percussion device, includes a housing and two movable bodies, an impact body for an impact pin protruding from the housing, and a balancing body for counterbalancing impact motions of the impact body. The housing includes springs, which constantly strive to bring the bodies towards each other and against the action of which the bodies may be separated axially. The balancing body is rotatable, via a drive spindle connected to a driving source the spindle being mounted in a bearing member, at least one of the bodies including an oblique surface, which, by contact against the other body, transforms the rotary motion of the balancing body into axial motions of the impact body. Rotation of the bearing member is prevented by a helical pressure spring attached to the bearing member and the housing. In this way, tangential vibrations cannot be transferred from the drive spindle to the housing.

Abstract: A power tool (1) has a percussive driving means for driving an impact tool (8). The driving means, which may be hydraulic or pneumatic, retracts the impact tool (8) on its return stroke, against the force developed by heavy-duty elastic ropes (24). During the impact stroke the impact tool (8) is urged downwardly by the elastic ropes and, if the tool is upright, by gravity. At the start of the impact stroke the ram (10) is uncoupled by means of a ball clutch. At the beginning of the return stroke the ball clutch acts to couple the ram once again to the weight (20) and impact tool (8), in order to lift these to the retracted position. It will be appreciated that the uncoupling of the ram for the impact stroke reduces the loss arising from the resistance of the ram.

Abstract: Disclosed is a reciprocating pneumatic tool including first, second and third piston retaining mechanisms for preventing the piston from freely exiting the barrel of the tool when the retaining sleeve and workpiece are removed. The retaining mechanisms are located within the lower portion of the tool barrel, and do not interfere with normal operation of the tool.

Abstract: A piercing apparatus compact in size having a decreased number of hoses is suited for use as an iron runner port-opening machine for a blast furnace or the like furnace in an iron mill.

Abstract: A device for use in combination with a pile driving apparatus for driving piles into the ground. The device (1) including a main body (13) which carries side grippers (18) and (19) each of which comprises a ram consisting of a piston and cylinder (20). A further gripper (23) is included, which extends downwardly of the main body (13) which grips the lower end of a pile, while grippers (18) and (19) are used to pick up and position a pile. A vibratory force generator (16) is operated to cause the main body (13) to vibrate thereby applying a downward vibrating force to the main body (13) and the pile held by the grippers (18, 19, 23), so driving the pile into the ground.

Abstract: A hand-held power tool for use in hand working operations including a hand pressure sensing element for adjusting the power of the tool. More specifically, the invention provides a hand engraving power tool that is activated from absence of power to much greater power or anywhere in between determined by the amount of pressure exerted by a human hand on the tool's handle.

Abstract: A rock drilling machine has a housing (1), a hammer piston (2) movable to-and-fro in the housing, a drilling tool (3), and a guide (4) for the drilling tool. The guide (4) consists at the surface against the drilling tool (3) of polyethyleneterephthalate.

Abstract: The invention relates to a hand power tool, in particular a percussion hammer, having a housing (10), a hammer barrel (12), and a tool receptacle (14) that is fixable in the direction of rotation (18) via at least one locking body (16).

Abstract: A pneumatic percussion operated mechanism for an at least partially percussion driven hand tool device (1) has a cup-shaped piston (2), in whose hollow space (4) an anvil (3) spaced radially inwardly displaceably penetrates inwardly within an axial penetration length (L), whereby the anvil (3) forms, together with the cup-shaped piston (2), a damping radial gap (X) relative to the essentially gas-tight, closed hollow space (4), which forces anvil (3) axially driven by the piston (2) inside the penetration length (L) to reversal of direction.

Abstract: A fastener installation tool to install fasteners, such as rivets, risers, standoffs, and other types of fasteners operates upon vacuum and air pressure. Fasteners are installed with minimal reactive forces to the operator's hand, thus reducing the risk of repetitive injuries to the operator's body. Vacuum retains the fastener within the tool tip and retracts a piston, until an operator simultaneously presses the fastener against a work piece and actuates an actuation element on the tool. This causes air pressure to quickly thrust the piston against a hammer pin to drive in the fastener, transferring kinetic energy from the piston to the fastener without appreciable kick-back to the operator. A control system provides a source of vacuum and air pressure to the tool. Methods of using a fastener installation tool are also described.

Abstract: The collapsible land anchor of this invention includes an anchor body, a drive anvil coupled to the top end portion of the anchor body, and a runner member that is slidable longitudinally through the drive anvil between an operative position and a collapsed position. A retraction anvil is coupled to the top end portion of the runner member, and a hammer weight is carried on the runner member. In its operative position, the runner member extends beyond the drive anvil away from the cavity of the anchor body to space the drive anvil apart from the retraction anvil. Also in the operative position, the hammer weight is slidable along the runner member into the drive anvil to drive the anchor body into the ground. In the collapsed position, the runner member is displaced towards and at least partially stowed in the cavity of the anchor body.

Abstract: A piercing apparatus compact in size having a decreased number of hoses is suited for use as an iron runner port-opening machine for a blast furnace or the like furnace in an iron mill.

Abstract: An anchor setting device for setting a concrete anchor into concrete and leaving a desired length exposed. The anchor setting device includes a body having a bore extending through the body. The body has a first end and a second end. The bore of the body is threaded for releasably receiving a threaded end of a concrete anchor. The body has a slot extending through a side of the body facilitating insertion of the threaded end of the concrete anchor a desired length into the bore. The first end of the body is designed for being struck by an impact device for driving the concrete anchor into a hole in an anchoring surface when the first end of the body is struck by the impact device. The second end of said body is designed for abutting against the anchoring surface when the concrete anchor is driven into the hole.

Abstract: A percussion rotary hand-held power tool including a percussion piston (3), an anvil (5), a chuck (4) for receiving a working tool, an axially displaceable and rotatable guide tube (6) located in the housing (2) and extending in a telescopic-like manner over the chuck (4) and the anvil (5) from a chuck region up to a region of the percussion piston (3), and a sealing element (8) located between the guide tube (6) and the housing (2) and having at least one axial seal (9) for performing only axial movement and at least one rotary shaft seal (10) for performing only rotary movement.

Abstract: An impact hammer system for driving an elongate member comprising a ram member, a frame assembly, an actuator assembly, and a power source. The ram member defines a ram bore. The frame assembly supports the ram member such that the ram member may move relative to the frame assembly between first and second positions. The actuator assembly is operatively connected between the frame assembly and the ram member and is operable in extended and retracted configurations. At least a portion of the actuator assembly is disposed within the ram bore and a substantial portion of the actuator assembly extends out of the ram bore when the cylinder is in the extended position. The power source is operatively connected to the actuator assembly to place the actuator assembly in the extended and retracted configurations. Extension and retraction of the actuator assembly moves the ram member between the first and second positions, respectively.

Abstract: A working tool for use with a percussion power tool and including a cushioning elongate stem (3), and a head (4) connected with the stem (3) for joint rotation therewith and for a limited axial displacement relative thereto, with the tool head (4) being adapted, with respect to its resistance associated with its cushioning properties, to characteristics of the percussion piston (5) of the power tool and with the tool stem (3) and the tool head (4) having mutually abutting each other end surfaces (10) which form at least a partially flat contact upon abutting each other.

Abstract: An apparatus for controlling a downhole drilling motor assembly includes a tubular housing having an interior sidewall which defines an interior bore. A mandrel is rotatably mounted within the interior bore of the housing. The mandrel has an exterior surface. A hydraulic dampener assembly is disposed between the interior sidewall of the housing and the exterior surface of the mandrel. The hydraulic dampener assembly limits the rate of rotation of the mandrel within the housing, thereby providing a preset resistance to reactive torque. The described apparatus can also be used as a steering tool by the addition of a feature that selectively blocks the flow of hydraulic fluids through the hydraulic dampener, thereby locking the mandrel in a selected directional position.

Abstract: An apparatus for a hand-held pneumatic impact tool for use in fine hand working operations includes a handpiece, a foot-operated flow control valve with exhaust and two hand operated flow control valves. The handpiece includes a housing having a cavity and annular shoulder accommodating a stepped piston dividing the cavity into three chambers. The control apparatus provides control for a hand-held pneumatic impact tool that will return an impacting handpiece to a fine oscillation idling state quickly when the user releases the foot-operated flow control valve. The apparatus also provides ease of control for adjusting the idling ready state of the handpiece to a faint oscillation idle.

Abstract: An improved bushing for a heavy duty hydraulic hammer provides increased bushing life and provides cooler operation for the hammer. A Polymeric bushing is positioned near the lower end of the tool holder of a hammer surrounding the tool. The polymeric bushing is protected by a steel ring below the polymeric bushing preventing foreign objects from impacting upon the polymeric bushing.

Abstract: A hand-held pneumatic impact tool for use in fine hand working operations includes a mechanism for adjusting impacting characteristics of the device that is conveniently located and adjusted by the user. The mechanism includes an annular band protruding around the outside diameter of the body of the impact tool that may be turned for adjusting an annular ring in the bore of the tool and thus altering the distance required for the piston to reach impact collision with the anvil. The impact tool also includes a handle containing a receiving-recess and a handle-attachment unit to permit manual removal and installation of the handle. The handle-attachment unit includes more than one protruding member positioned a distance into the receiving-recess, more than one groove on the outside diameter of body and running a distance and in a direction substantially parallel with the central longitudinal axis of the body and then changes direction and rotates around the central longitudinal axis of the body a distance.

Abstract: An electrically powered hammer comprising a hollow spindle within which spindle is reciprocatingly mounted a piston, a ram, a beatpiece having an increased external diameter mid-portion and located within the spindle between the ram and the tool or bit, a two part sleeve arrangement located within the spindle and including an increased internal diameter mid-portion for receiving the increased external diameter portion of the beatpiece and a reduced internal diameter forward and rearward portion for guiding the forward and rearward ends respectively of the beatpiece and where the sleeve arrangement includes a forward sleeve and a rearward sleeve which are both guided with tight radial tolerances and with a slight axial play within and by the spindle and the forward axial movement of the forward sleeve is limited by a reduced diameter portion of the spindle and the forward axial movement of the rearward sleeve is limited by the forward sleeve.

Abstract: A hand-held pneumatic impact tool for use in fine hand working operations includes a mechanism for adjusting impacting characteristics of the device that is conveniently located and adjusted by the user. The mechanism includes an annular band protruding around the outside diameter of the body of the impact tool that may be turned for adjusting an annular ring in the bore of the tool and thus altering the porting and the impacting characteristics of the impacting piston. The impact tool also includes a tubing attachment barrel that may be slid or rotated around the impact tool for position the tubing attachment location for user comfort, a housing having a cavity and annular shoulder accommodating a stepped piston dividing the cavity into three chambers.

Abstract: A percussion rotary hand-held power tool including a percussion piston (3), an anvil (5), a chuck (4) for receiving a working tool, an axially displaceable and rotatable guide tube (6) located in the housing (2) and extending in a telescopic-like manner over the chuck (4) and the anvil (5) from a chuck region up to a region of the percussion piston (3), and a sealing element (8) located between the guide tube (6) and the housing (2) and having at least one axial seal (9) for performing only axial movement and at least one rotary shaft seal (10) for performing only rotary movement.

Abstract: An electrical hand held tool including a percussion mechanism (2) with a striker (3) having a striking region (6), a chuck (4) for receiving a working tool (7); and an annular channel (8) provided in the striking region (6) of the striker (3); and having at least one side opening (9) communicating with the underpressure-producing ventilation system (5) of the electromotor of the hand-held tool.

Abstract: The invention relates to an arrangement in connection with a hydraulic breaking apparatus, the arrangement comprising a housing (4) placed around a percussion hammer (1), and a changeable wearing element (6) arranged at the lower part of the housing. The wearing element (6) receives blows and forces directed at the lower part of the housing (4). The wearing element (6) is fastened in such a way that it can be detached and changed easily and rapidly, if required. Further, the structure of the breaking apparatus may also be such that when the wearing element (6) is removed, it is possible to carry out the maintenance and repair operations of the lower frame (1b) of the percussion hammer without disassembling the upper frame (1a) of the percussion hammer.

Abstract: An impacting device is capable of being used in an impact hammer and/or a drill for releasing by impact tools blocked in rocks. An impact impetus supplied by an impact piston is modified via an impact-deflecting device having a sliding lever and a deflecting lever, such that the impact is carried out in a releasing impact direction opposite the normal impact direction and is transmitted to a tool by a slide and a locking lever. The tool is released after a few strokes produced by the impact piston. The impact device is suitable for both unilateral air springs and double air springs.

Abstract: A protective apparatus for preventing the infiltration of contaminants in a fluid-operated percussion device, having a striking tool (3) that is guided to move in a housing (2) and is driven by a percussion piston in the striking direction (arrow 1), and a seal (7) that is supported at least indirectly on the housing (2), on the one hand, and on the striking tool (3), on the other hand, and has a securing segment that is fixedly disposed with respect to either the housing or the striking tool. The seal (7) is disposed between the inner guide portion (5b) of the striking-tool guide and the theoretical striking plane (4) of the percussive piston on the striking tool (3), when seen in the direction opposite the striking direction (arrow 1), such that the countersurface (3e) for the seal, which countersurface moves relative to the securing segment (7a) of the seal (7) and is in contact with the seal, is unaffected by wear.

Abstract: A rotary impacting apparatus is provided which comprises a housing, a rotor rotatably accommodated in the housing, a driving source for rotating the rotor about a rotation axis, a main reciprocative implement reciprocatively held by the housing, and an impact member eccentrically held by the rotor. The impact member exerts an impacting force for pressing the main reciprocative implement when the main reciprocative implement is advanced relative to the rotation axis. The main reciprocative implement is provided with a diametrically smaller portion and a diametrically greater portion connected to the diametrically smaller portion.

Abstract: A rotary impacting apparatus is provided that includes a housing, a rotor rotatable about an axis, a main reciprocative implement and an impact member. The impact member is arranged to exert an impacting force on the main reciprocative implement when the main receprocative implement is advanced relative to the axis. The rotor is supported by the housing via needle bearings.