Abstract: An impact tool includes a motor, a hammer casing with an opened rear end and a disk-shaped member coupled to the hammer casing to close the opened rear end and to rotatably support a spindle. A first engagement member is formed on an outer face of the disk-shaped member. A second engagement member is formed on an inner face of the recess and engaging with the first engagement member to restrict a movement of the hammer casing in a second direction parallel to a rotation axis of the spindle. A third engagement member is formed on an outer face of the hammer casing. A fourth engagement member is formed on an inner face of the housing body and engaging with the third engagement member so as to restrict a movement of the hammer casing in the first direction.

Abstract: The invention relates to a hand-held machine tool, particularly to a drill hammer and/or chisel hammer, having a hand-held machine tool housing and a transmission chamber with at least one transmission element arranged inside the hand-held machine tool housing. According to the invention, the hand-held machine tool includes a pressure equalization unit, provided for equalizing pressure in the transmission housing and serving at least partially for supporting the transmission element.

Abstract: The disclosure relates to a method of assembling a hand machine tool having (i) an intermediate flange that includes (i) at least one base body having a slot-shaped opening extending in a bearing position and in a bearing, (ii) an intermediate shaft assembly that includes an intermediate shaft and a wobble bearing having a wobble pin, and (iii) a drive piston. The method includes sliding the drive piston onto the wobble pin, introducing the wobble pin into the slot-shaped opening such that the drive piston slides into the at least one base body, and inserting, in an assembly direction corresponding to a direction of a longitudinal axis of the base body, the intermediate shaft of the intermediate shaft assembly into a second base body of the immediate flange.

Abstract: A manually operated hammer drill (1) includes a spindle (3) that drives a chuck (5) in a rotary manner about an axis of rotation (6) in a drilling mode, and includes a pneumatic hammer mechanism (4), that hammers against a tool inserted in the chuck (5) in a hammer mode. The hammer mechanism (4) has a piston (10) which performs reciprocating movements (12) parallel to the axis of rotation (6) in a cylinder (11) conformed inside the spindle (3) when hammer mode is activated. The piston (10) has at least one radial groove (21) in which an annular seal (22) is arranged.

Abstract: A percussive augmenter bit includes a connection shaft for mounting the bit onto a rotary drill. In a first modality, an actuator percussively drives the bit, and an electric slip-ring provides power to the actuator while being rotated by the drill. Hammering action from the actuator and rotation from the drill are applied directly to material being drilled. In a second modality, a percussive augmenter includes an actuator that operates as a hammering mechanism that drives a free mass into the bit creating stress pulses that fracture material that is in contact with the bit.

Abstract: A method of operating a rotary tool driven by a brushless motor including a DC brushless motor for rotationally driving a rotary bit, a torque setting clutch mechanism, a drive switch for drive-controlling a drive control circuit of the brushless motor, and a control means to rotationally drive the brushless motor by an operation of the drive switch and wherein the method includes a first step for stop-controlling of the drive control circuit, a second step for rotating forward or in reverse the brushless motor through the control and a third step for control-operating a semiconductor of an inverter circuit provided in the drive control circuit to short-circuit the magnetizing windings of the brushless motor, thus braking the rotor of the brushless motor and stopping the brushless motor.

Abstract: A hand-operated power tool, particularly a hammer drill (1), includes a drive motor (2), a tool spindle (3) to drive a tool in rotary manner, a rotary drive transmission (4) to couple the drive motor (2) to the tool spindle (3), a hammer mechanism (5) to drive the tool in percussive manner, a hammer mechanism transmission (6) to couple the drive motor (2) to the hammer mechanism (5), and a switching device (7) to activate and deactivate the hammer mechanism (5). The switching device (7) has a clutch (9) that is integrated in a force path (10) of the hammer mechanism transmission (6) and has an actuation stroke (11) for advancing and withdrawing the clutch (6), which stroke extends perpendicularly to the axis of rotation (8) of the tool spindle (3), or parallel to an axis of rotation (37) of an actuating element (28) that is rotated manually to actuate the switching device (7) for advancing and withdrawing the clutch (6).

Abstract: A hammer mechanism has a clamping chuck and a snap die provided for the direct striking of an inserted tool. The snap die includes a coupling element for transmitting a rotary motion to the clamping chuck.

Abstract: A control system is disclosed for use with a machine having a work tool and operating at a work site. The control system may have a sensor associated with the work tool and configured to generate a signal indicative of a position of the work tool, an offboard worksite controller, and an onboard controller in communication with the sensor and the offboard worksite controller. The onboard controller may be configured to receive from an operator an input indicative of a current task being performed by the machine, and track movement of a portion of the work tool corresponding with the operator input. The onboard controller may also be configured to communicate the tracked movement to the offboard worksite controller.

Abstract: A modularized ultrasonic vibration machining apparatus is provided, which includes a tool holder module. The tool holder module further includes: a housing, having a positioning pin disposed thereon; a tool holder linking part, disposed in the housing; a transmitting mechanism, disposed in the housing and linked to the tool holder linking part in a transmission manner; an expanding device, disposed in the housing and linked to the transmitting mechanism in a transmission manner; a piezoelectric element, disposed in the housing and linked to the expanding device; and an electrical connector, disposed in the housing and electrically connected to the piezoelectric element and the positioning pin. Therefore, the modularized tool holder has an internal vibration mechanism and closed circuit setting of power supply, is capable of being assembled and applied conveniently, and has good security, economical efficiency, and applicability in industry.

Abstract: The invention relates to a hand-held machine tool, in particular a hammer drill and/or chipping hammer. The tool according to the invention has a transmission device with a drive bearing that has at least one torque-transmitting means with a transmitting contour for transmitting a torque onto the drive bearing. According to the invention, the transmitting contour of the torque-transmitting means is produced by axial machining and/or a stamping and/or planning process.

Abstract: A screw driving machine includes a bit that is movable to strike a screw against a workpiece and rotatable to rotate the screw to the workpiece, a combustion-type power mechanism including a spark plug that ignites combustible gas filled in a combustion chamber to apply striking force to cause the bit to strike the screw, a motor that generates a rotative force when supplied with electric force, and a power transmission mechanism that transmits the rotative force generated at the motor to the bit to cause the bit to rotate.

Abstract: A power tool having a housing assembly and a drive component that is housed in the housing assembly. The housing assembly has a first housing component, a second housing component, at least one set of mating conically-shaped features, and at least one fastener. Each set of mating conically-shaped features includes a first cone portion and a second cone portion. The first cone portion of each set of mating conically-shaped features is coupled to the first housing component and has a frusto-conically-shaped exterior surface. The second cone portion of each set of mating conically-shaped features is coupled to the second housing component and has a frusto-conically-shaped interior surface that is engaged with the frusto-conically-shaped exterior surface of an associated first cone portion. Each fastener is received through an associated pair of the first and second cone portions and is threadably engaged to one of the first and second housing components.

Abstract: A rotary hammer includes a motor, a spindle coupled to the motor for receiving torque from the motor, a piston at least partially received within the spindle for reciprocation therein, a striker received within the spindle for reciprocation in response to reciprocation of the piston, and an anvil received within the spindle and positioned between the striker and a tool bit. The rotary hammer also includes a retainer received within the spindle for selectively securing the striker in an idle position in which it is inhibited from reciprocating within the spindle, and an O-ring positioned between the retainer and the spindle. The O-ring is disposed around an outer peripheral surface of the anvil. The O-ring is compressible in response to the striker assuming the idle position. The compressed O-ring imparts a frictional force on the outer peripheral surface of the anvil to decelerate the anvil.

Abstract: A mechanical assembly for a power tool, and a power tool incorporating the mechanical assembly are provided. The mechanical assembly includes (i) a first member having a first axis and a first engagement portion inclined relative to the first axis, (ii) a second member having a second axis and a second engagement portion inclined relative to the second axis, wherein the first and second engagement portions engage each other by movement of the first and second members relative to each other in the direction of at least one of the axes; and wherein the first member is a ring gear and the second member is a central gear and the first and second engagement portions engage and disengage each other by movement of the second member within a space defined within the first member.

Abstract: It is an object of the invention to provide a power tool that effectively prevents leakage of lubricant while regulating the internal pressure of a housing space for a driving mechanism. The object can be achieved by a representative power tool that includes a too bit 119, a driving mechanism 113, 115, an enclosed housing space 107a which houses the driving mechanism and in which lubricant is sealed in, and a path 151 which regulates pressure of the housing space 107a. On the path, a filter chamber 154 having a predetermined capacity, an inner passage 155c that communicates the filter chamber 154 with the housing space 107a, and an outer passage 159c that communicates the filter chamber 154 with the outside are formed. A filter 157 is disposed in the filter chamber 154 and spaced apart from a peripheral edge of an opening of the outer passage 159c which is open to the filter chamber 154, so that a space 161 is created on the opening edge side of the filter chamber 154.

Abstract: The invention relates to a gearbox device, in particular, for a hammer drill or chisel, with a torque transmission mechanism, which has a first torque transmitting region for transmission of a torque to a first component and at least one second torque transmitting region for transmitting a torque to a second component. According to the invention, the first torque transmitting region and the second torque transmitting region at least partly have a corresponding partial contour for transmitting the torques.

Abstract: The pneumatic tool having pendulum-like direction switching mechanism of the present invention includes a pneumatic motor and a control valve. The control valve is utilized for receiving pressurized air and for alternatively leading air into the pneumatic motor to drive and control the pneumatic motor. The present invention further includes a switching device and a coupling mechanism. By connection of the coupling mechanism, the switching device is able to control motion of the valve. In addition, the switching device slides along an arc-shaped route. Thus, the switching device approaches the pneumatic tool without protruding excessively. Therefore, unexpected collision is lessened and lifetime is prolonged.

Abstract: Disclosed is a striking tool technology that contributes to reducing clutch sizes. The striking tool causes a tool bit to perform a striking operation in the long axis direction and to perform a rotational operation about the long axis, thereby causing the tool bit to carry out a predetermined machining operation. The striking tool comprises a tool body; a motor which is housed in the tool body and drives the tool bit; and a clutch which, on a route where the torque of the motor is transmitted to the tool bit, is disposed in a high rotational speed and low torque region that is a stage prior to where the rotational speed of the motor is reduced, which transmits the torque of the motor to the tool bit in a normal state, and which cuts off the transmission of torque generated about the tool bit long axis in the tool body if the torque exceeds a predetermined torque level.

Abstract: A drive mechanism for a hammer drill comprises a hollow piston 558 having a cylindrical bearing that is adapted to receive a crank pin in order to cause the hollow piston 558 to reciprocate inside a spindle 548. A plurality of longitudinal ridges 559 are formed on the outer surface of the hollow piston 558 to reduce the surface area of contact between the hollow piston 558 and the spindle 548, and a plurality of grooves 561 are formed in the gaps between the ridges. The grooves 561 are adapted to retain lubricant 563 in order to reduce frictional contact between the hollow piston 558 and the spindle 548.

Abstract: The invention relates to a hand-held power tool, in particular a hammer drill which has a hammer drive, a rotary drive, a switching device, and a main output element. The switching device has a slide mechanism, which is designed for switching between different operating modes. According to the invention, the slide mechanism has at least one coupling element, which in at least one operating mode is directly coupled to a coupling element, the latter being rotationally fixed to the main output element.

Abstract: A direction switching and speed controlling device for an air tool includes two holes provided respectively on two lateral sides of an air cylinder (2). Holes on one side are two air outlets (8), and two holes on another side are a forward rotation air inlet (13) and a reverse rotation air inlet (12). An air valve (7) has an indentation portion (9) provided on a lateral side thereof, the indentation portion (9) is engaged with teeth portion (10) provided on a lower end of a switch (6). At another end, the switch (6) includes an elongated portion (11) provided horizontally with a blind hole (14) provided in the center. A spring (3) is disposed into the hole (14) with a metal ball (4) attached to an end thereof. A valve cap (5) is provided on a bottom portion of a casing (1) with a plurality of spherical grooves (15) provided therein. The metal ball (4) and groove (15) are engaged through the restoration force of the spring (3).

Abstract: In an upper surface of a crank housing is provided an inlet for grease which is configured to be openable and closable by a cap. A vibration damping mechanism, which includes a counterweight provided with a connecting pin loosely fitted in a connecting hole of an eccentric pin when the cap is attached, is mounted in the cap, whereby the vibration damping mechanism is allowed to be taken in and out of the crank housing through the inlet by attachment and detachment of the cap to and from the inlet.

Abstract: A hand-held power tool includes a motor-driven percussion mechanism. The percussion mechanism includes a guide tube (21) and a reciprocating driving member (22) displaceable in the guide tube (21) for driving, via a gas spring, an impact member (23) likewise displaceable in the guide tube (21). The percussion mechanism further includes a motor-driven eccentric wheel (17) rotatable about an axis (D) which is spaced from the percussion mechanism axis (S) in a direction perpendicular to the percussion mechanism axis (S) by a distance (X). A connection rod (29) is eccentrically supported on the eccentric wheel (17) and connected to the driving member (22) for converting a rotational movement of the eccentric wheel (17) into a reciprocating movement of the driving member (22).

Abstract: A tool holder for a hand-guided drilling device, in particular for a rotary hammer, includes a receiving sleeve that is designed as a single piece and that is drivable in a rotating manner for a shank part of an insertion tool. The recess is open at both end faces and limited therebetween by an inner circumferential surface of the receiving sleeve. The inner circumferential surface (62) of the receiving sleeve (34) includes at least six flat circumferential surface sections (62n through 62u; 84, 86) in the circumferential direction, with adjacent circumferential surface sections (62n, 620; 62p, 62q; 62r 62s; 62t, 62u) forming an angle of 120 degrees.

Abstract: A concrete screw is disclosed. The concrete screw has a shaft section, a thread section, which is arranged on the front end of the concrete screw and is provided with at least one expansion slot, and an expansion element, which is allocated to the expansion slot such that the expansion element expands the expansion slot during screw-in. A method and a tangential impact screwdriver for driving in such a concrete screw are also disclosed.

Abstract: The invention relates to a gearbox device, in particular, for a hammer drill or chisel, with a torque transmission mechanism, which has a first torque transmitting region for transmission of a torque to a first component and at least one second torque transmitting region for transmitting a torque to a second component. According to the invention, the first torque transmitting region and the second torque transmitting region at least partly have a corresponding partial contour for transmitting the torques.

Abstract: A hand-held power tool, in particular an impact drill driver, has a gearbox assemblage, a hammer impact mechanism, and a tool spindle. The hammer impact mechanism includes a striker that at least partly surrounds the tool spindle in at least one plane.

Abstract: A rotary switch for shifting a switch element is disclosed. The switch includes a twist handle, a torsion spring, a rotatable actuating element and a common axis. The twist handle, the torsion spring and the rotatable actuating element are supported so as to be rotatable about the common axis. The twist handle and the rotatable actuating element are coupled with each other by the torsion spring in such a manner that a twisting of the twist handle relative to the rotatable actuating element twists the torsion spring. An eccentric is provided on the rotatable actuating element in order to convert a rotary motion of the rotatable actuating element into a shifting motion of the switch element.

Abstract: The present invention provides both an impact switching function and a shaft locking function for use in an impact screwdriver. The impact screwdriver includes a housing, a motor located in the housing, a motor drive shaft driven by the motor, a hammer which can move axially and rotate around the motor drive shaft, a hammer anvil, an impact switching device and a shaft locking apparatus. The shaft locking apparatus has a mating member coupled with the hammer anvil, an engagement ring fixed to the housing and a middle member located between the mating member and the engagement ring. The shaft locking apparatus has a locked position, where the mating member is secured to the hammer anvil and also secured to the engagement ring and the housing.

Abstract: It is an object of the invention to easily determine a currently-selected operation mode in a power tool which offers several operation modes. A representative electric hammer drill 101 embodying a power tool according to the invention has a controller 171 for at least controlling a driving motor 111. The controller 171 includes a switch detecting circuit 173 that detects the on or off state of each of first and second switches 141, 146 when power is on, a computing/driving section 174 that determines a current operation mode based on results of detection of the switch detecting circuit 173, and a motor control section 176 and a drive circuit 177 that output a drive control signal to the driving motor 111 when the switch in the off state is turned on after the computing/driving section 174 determines the operation mode.

Abstract: A power tool has a mechanism for ejecting a battery pack which includes a receiving frame which defines a cavity to receive a battery pack. A receiving member is adjacent the cavity. The receiving member meshes with a member on the battery pack to hold the battery pack in the cavity. A biasing member is in the cavity adjacent the receiving member. The biasing member ejects the battery pack from the ejecting mechanism. A member retains the biasing member in the cavity. The member guides a portion of the battery pack meshing with the receiving member into contact with the biasing member such that when the battery pack is locked onto the frame, the biasing member is in a compressed condition and when the battery pack is an unlocked position, the biasing member ejects the battery pack from the frame.

Abstract: The invention relates to a gearbox device, in particular, for a hammer drill or chisel, with a torque transmission mechanism, which has a first torque transmitting region for transmission of a torque to a first component and at least one second torque transmitting region for transmitting a torque to a second component. According to the invention, the first torque transmitting region and the second torque transmitting region at least partly have a corresponding partial contour for transmitting the torques.

Abstract: In a hand-held power tool having a housing and a tool holder, which is disposed on a drive shaft that is rotationally mounted in at least one first and one second ball bearing, the first ball bearing having a first inner ring and the second ball bearing having a second inner ring, a spring element is disposed between the first inner ring and the second inner ring in order to prestress the first ball bearing with respect to the second ball bearing.

Abstract: A quick assembly pneumatic tool may be connected to a tool bit and has a housing, an anvil casing, a rear cover, an air inlet assembly, a rotor assembly and an impact assembly. The housing has a handle and a rotor casing. The rotor casing is formed on the handle and has a front chamber and a rear chamber. The anvil casing and rear cover respectively cover the front and rear chambers. The rotor assembly is mounted in the rear chamber and is selectively driven by the air inlet assembly. The impact assembly is mounted in the front chamber and the anvil casing and is selectively rotated by the rotor assembly. The separate rotor and anvil casings allow the rotor and impact assemblies to be inserted respectively in the front and rear chambers so that assembling the pneumatic is easy and quick.

Abstract: A device has a torque-limiting unit of a power drill, wherein torque-limiting unit is intended to limit a screwdriving moment in a screwdriving function; and a power drill is provided with the new torque-limiting unit.

Abstract: An impact rotary tool is provided that is switchable between an impact mode where the tool delivers an impacting torque on an output tool and a drill mode where the driver delivers a smooth output on an output tool. The impact rotary tool includes an impact mechanism and a hammer block that in the impact mode is movable parallel to the axis of the driver shaft and delivers reciprocating blows to rotate an anvil and in the drill mode substantially constantly engages the anvil. The impact mechanism includes a stopper that does not contact the hammer block in the impact mode and engages the hammer block in the drill mode to maintain the substantially constant contact between the hammer block and the anvil.

Abstract: A drill includes a housing and a motor coupled to an output member by a transmission. The transmission can selectively couple the output member to an output spindle through a low speed output gear or a high speed output gear for rotating the output spindle at a first speed or a second speed, respectively. Alternatively or additionally, a low speed mode can be provided by actuating an electronic switch that limits the speed of the motor. A rotatably fixed hammer member and a rotatable hammer member can be mounted around the output spindle. A mode collar can be rotatably mounted on the housing and around the output member for movement to positions that correspond to various mode of operation, including a low speed mode, a high speed mode, and a hammer-drilling mode. In the hammer-drilling mode, the transmission operates in the high speed mode.

Abstract: The invention relates to a hand machine tool, in particular, a hammer drill or chisel, having a gearbox housing and a gearbox unit with a switching device. The switching device includes a switching spring and an operating unit which may be mounted in the gearbox housing with a transfer element. According to the invention, the switching spring has a housing region provided for housing the transfer element of the assembled operating unit, on assembly of the gearbox housing and the gearbox unit.

Abstract: An oil pulse rotary tool includes a motor, a speed reduction mechanism to which rotation is transmitted from the motor, and an oil pulse generator disposed in front of and coaxially with the speed reduction mechanism. The motor, the speed reduction mechanism, and the oil pulse generator are housed in a housing. A carrier portion is provided coaxially with the oil pulse generator to project from a rear portion of the oil pulse generator. Support shafts that support planetary gears provided in the speed reduction mechanism are fixed to the carrier portion. A bearing is provided between the planetary gears and the oil pulse generator to support the carrier portion.

Abstract: A hand-held power tool has a handle, a least one two-speed transmission, at least one switch element for shifting the transmission between various gear ratios, wherein a distance between the switch element and a gripping region of the handle provided for placement of an operator's hand is less than or equal to a maximum finger extension range.

Abstract: An impact tool includes: a spindle disposed in a housing; an anvil disposed in front of the spindle and rotatably supported by the housing through a metal bearing, a rear surface of the anvil having a bearing hole in which a front end of the spindle is received; an impact mechanism configured to transmit a rotation of the spindle to the anvil; an outer groove formed on an outer periphery of the anvil and opposed to the metal bearing; and a connecting opening radially extending in the anvil and connecting the bearing hole and the outer groove to provide a communication therebetween. The outer groove is formed to have a depth in the range of 3-10% of an outer diameter of the anvil, and the connecting opening opens at a rear end of the outer groove in an axial direction of the anvil.

Abstract: A rock drilling machine equipped with an axial bearing having at least one axial piston for setting the axial position of a drill shank and for damping stress pulses returning from the rock. The axial bearing includes a module that is detachable in one piece from one installation direction. The axial bearing module includes all necessary seals, bearing surfaces, and a module frame. Supporting forces caused by the operation of the axial bearing are transmitted of support members in the module frame directly to the body of the rock drilling machine, which is a uniform piece at least at the axial bearing.

Abstract: The invention is to provide a hammer drill which is to be capable of restricting rotation of a bit in a hammer mode, and improve usability. A hammer drill includes a lock plate 51 in a housing 2, and the lock plate 51 engages with a second gear 31 so as to lock rotation of the second gear. The lock plate 51 is provided to be slidable between an engaging position with the second gear 31 and a non-engaging position, and is biased to the engaging position by a coil spring. The hammer drill further includes a restriction part 50 on an outer peripheral side of a holding tube 46 in a mode switching knob 44. The restriction part 50 abuts the lock plate 51 in one of two phases for engaging a clutch 37 with only a boss sleeve 32 so as to hold the lock plate 51 at the non-engaging position, and cancels the abutment with the lock plate 51 in the other phase to slide the lock plate 51 to the engaging position.

Abstract: A portable power tool has a housing, a rotating sleeve provided for rotatably driving a tool and a rotatably supported in the housing by at least one bearing, a driving gear-wheel installed on the rotating sleeve in a freely rotating manner and drivable by a motor, a safety clutch that couples the driving gear-wheel with the rotating sleeve in a rotation-proof manner, the safety clutch having two clutch members that are slippable, with one of the clutch members being assigned to the driving gear-wheel and the other clutch member being assigned to the rotating sleeve in both cases in a rotation-proof manner, and with a coupling sleeve providing a force against which the clutch members are slippable when a limit torque is exceeded, the bearing being seated on the rotating sleeve in an axially displaceable manner and loaded by the coupling sleeve of the safety clutch against an axial stop of the rotating sleeve.

Abstract: A drill includes a housing and a motor coupled to an output member by a transmission. The transmission can selectively couple the output member to an output spindle through a low speed output gear or a high speed output gear for rotating the output spindle at a first speed or a second speed, respectively. Alternatively or additionally, a low speed mode can be provided by actuating an electronic switch that limits the speed of the motor. A rotatably fixed hammer member and a rotatable hammer member can be mounted around the output spindle. A mode collar can be rotatably mounted on the housing and around the output member for movement to positions that correspond to various mode of operation, including a low speed mode, a high speed mode, and a hammer-drilling mode. In the hammer-drilling mode, the transmission operates in the high speed mode.

Abstract: A rotary impact tool includes a drive shaft rotationally driven by a rotational drive power source, a hammer arranged around the drive shaft, a ball engaging with a cam groove formed on the outer circumferential surface of the drive shaft and a cam groove formed on the inner circumferential surface of the hammer, an anvil engageable with the hammer along a rotational direction and a spring for biasing the hammer toward the anvil. The hammer is designed to rotate along a rotational locus decided by the cam groove of the drive shaft and the cam groove of the hammer. The rotational locus of the hammer as seen in a development view describes a curve in which the lead angle of the rotational locus varies continuously with the change in hammer rotation angle.

Abstract: A hand-held power tool includes a percussion power tool includes a percussion piston (5) for applying blows to an anvil (8) axially displaceable in a guide tube (6) within limits defined by two, spaced from each other, stops (9a, 9b) arranged in the guide tube (6), a pneumatic percussion mechanism (2) for driving the percussion piston (5), an air spring (3) for connecting the percussion piston (5) with the percussion mechanism (2), and an impact ring (12) arranged coaxially with the anvil (8) outwardly thereof and having spaced from each other, inner radical flanks (14) located on opposite axial sides of the outer radial collar (11) provided on the anvil (8), with the impact ring (12) freely axially displaceable, within limits, relative to the outer radial collar (11) and having an outer diameter smaller than a guiding inner diameter of the guide tuber (6), and with a mass ratio of the impact ring (12) to the anvil (8) being equal at least 0.25.

Abstract: A pile driver enables angle adjustment and pile core adjustment of a leader to be performed easily, by minimizing an angle change of the leader when the pile core adjustment is performed. In the pile driver, an upper part of the leader is supported by a leader erect cylinder from behind, and a lower part of the leader is supported by a forward and backward adjustment means that includes a leader arm having a rotation base rotatably attached to a base machine and a rotation end rotatably attached to the lower part of the leader. A first arc traced by the rotation end when the leader arm is rotated to adjust the lower part of the leader forward and backward and a second arc traced by a connection part between the leader and a tip of the leader erect cylinder when the lower part of the leader is adjusted are both convex upward. The first arc has a smaller radius than the second arc.

Abstract: In a hammer drill, a coil spring is disposed rearward of a piston cylinder inside a housing so as to press the piston cylinder to an advanced position when the hammer drill operates in a drill mode, and a supporting plate is disposed at a rear end of the piston cylinder. The supporting plate includes a pair of side plates and a base portion connecting front ends of the side plates. The base portion is in contact with a rear surface of the piston cylinder, and rear ends of the side plates are in contact with a front end of the coil spring. Openings provided in the side plates are configured to hold a pin on which a connecting arm is pivoted.