Abstract: An impact hammer has a housing, a motor accommodated in the housing, an impacting mechanism accommodated in the housing and having a driver and a striker which is displaced by the driver in an axial direction and periodically strikes a shaft of a tool with the driver being tiltable about a tilting axis, a driving element which drives the driver into a reciprocating motion and a shaft which rotates the driving element. The driving element is provided with two interengaging eccentric parts including a first eccentric part which is non-rotatably connected with the shaft and a second eccentric part which is axially displaceable relative to the shaft. The eccentric parts have ring surfaces each surrounding the shaft, arranged asymmetrically relative to one another and being in contact with one another.

Abstract: The invention provides an improved intermediate housing incorporated in a power driven hammer drill, which is light in weight, easily and safely handled, and uncostly manufactured. The intermediate housing of the invention includes a bearing member and a cylindrical piston housing member which are integrally composed of a synthetic resin having high tenacity and excellent heat resistance and wear resistance. The intermediate housing further includes a plurality of ribs radially extending from the piston housing member to give a sufficient strength durable to a stress applied onto the piston housing member. In the intermediate housing thus constructed, the bearing member has at least one opening for feeding an air flow generated by a fan while the piston housing member includes at least one air conduit for circulating the air flow. This structure efficiently prevents overheat and thermal deformation of the piston housing member and the bearing member in continuous operation of the hammer drill.

Abstract: Driving means in particular for a cutting-off device with a rotationally held cutting-off tool. In order to provide the cutting-off tool with high acceleration in a simple manner, a sledge hammer (6) is provided that cooperates with an impact surface (5) arranged on a rotationally held cutting-off tool (4). Furthermore, a cam (2) is arranged on at least one driven rotating inertial body (1) for acting upon said sledge hammer, whereby said inertial body (1) is driven at an essentially constant, optionally adjustable speed.

Abstract: A tightening tool includes a hammer for impacting on an anvil which drives a nut etc. A microphone is provided for converting impact sounds of the hammer on the anvil into an electric signal. A counting device counts the number of pulses of the electric signal. A setting device is provided for setting a set number of impacts to be obtained. A switch device compares the counted number of pulses with the set number and stops a motor for driving the hammer when the number of pulses coincides with the set number.

Abstract: A tightening tool includes a hammer for impacting on an anvil which drives a nut etc. A microphone is provided for converting impact sounds of the hammer on the anvil into an electric signal. A counting device counts the number of pulses of the electric signal. A setting device is provided for setting a set number of impacts to be obtained. A switch device compares the counted number of pulses with the set number and stops a motor for driving the hammer when the number of pulses coincides with the set number.

Abstract: A power tool has a tool spindle, a hammer unit, a drive including a motor having a motor driven shaft, a motion conversion gear for generating reciprocating piston movement, and a disengageable coupling located between the motor and the motion conversion gear and engaging the hammer unit. The coupling has two coupling parts which held apart, one of the coupling parts being axially fixed and another of the coupling parts being axially movable and arranged on the motor-driven shaft rotatable relative to the shaft. A gear linkage connects the another coupling part with the shaft and transmits portions of a torque of the shaft to the another coupling part in form of an axially directed closing force.

Abstract: A hand held power tool, particularly a hammer drill has a housing, a drive shaft, a rotatable tool holder, a safety coupling provided between the drive shaft and the tool holder, and a switching member supported with a bearing axis extending substantially parallel to the drive shaft and freely movable about the bearing axis in a plane extending substantially perpendicularly to the drive shaft. The switching member during a rearward rotation of the housing about an axis of the tool holder engages in the safety coupling and releasing the safety coupling.

Abstract: An electric power tool of the type which has an inserted tool bit (8), which can be operated with a rotary and a hammer action, and comprises a hammer which can be activated by axial displacement of the tool bit (8) by engagement with the work piece, also comprises a manually operable adjustment handle which can be rotated about an adjustment axis (59) between a first position in which a stop element (53) permits the axial displacement for the activation of the hammer means, and a second position in which the stop element (53) blocks the axial displacement. The stop element (53) is connected with cam surface (61, 62) which is coupled with an adjustment element (41) movement of which switches between high and low speeds of the tool. The cam surface has an arc-shaped portion (61) circular about the adjustment axis (59). Connected to one end of the arc-shaped portion(61) of the cam surface is a curved second portion (62), the distance of which from the adjustment axis (59) changes continuously.

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: A power drill has a mode changing mechanism enabling the drill to be operated selectively in a hammer mode and a non-hammer mode. Pivotally mounted upon an internal partition of the drill is a mode changing mechanism comprising a first rigid limb and a second limb consisting of a leaf spring located in side-by-side relationship with the first limb. The mechanism is pivotable into a first position in which the rigid limb is directly behind the output shaft of the drill so preventing rearward movement of the shaft and enabling the drill to operate in a non-hammer mode, and a second position in which the leaf spring is directly behind the output shaft so allowing rearward movement of the shaft and enabling the drill to operate in a hammer mode.

Abstract: This invention relates to a device for driving a drilling or percussion tool having a spindle that rotates with respect to a housing. One end of the spindle is adapted to fasten to a tool piece and the other end is connected to an osciliating percussion body movable in the housing by means of a guideway. A drive shaft rotates the tool spindle into rotation or actuates the percussion body via a transmission that is provided with means for converting the rotary motion of the drive shaft into an oscillatory motion of a drive member. The drive member is connected to the percussion body through an elastic member having a non-linear spring characteristic.

Abstract: The invention provides a portable power tool which is lightweight and convenient to use by the general public in any of its various forms, as a wallpaper stripper, a paint scraper or a cold chisel up to a power spade. The tool comprises a housing (12), a drive means, conveniently an electric motor (14,160) adapted to drive a selected tool bit (4,56,62,64,66,68), the output shaft (44) moving in a reciprocating axial movement. Conveniently the drive means may be a linear motor (160) or if used with a cam device, a rotary motor (14). The cam device may be a cylinder cam (32) provided with a sinusoidal cam track (34).

Abstract: A rotary hammer has a pneumatic hammering mechanism driven by a wobble plate drive arrangement. A rotatably driven intermediate shaft transmits torque for rotating a tool holder. A carrier sleeve is rotatably mounted on the intermediate shaft and is elastically coupled with the intermediate shaft for limited rotational displacement relative thereto. The tool holder is rotatably driven via gearing by the carrier sleeve. On a suitable portion of the carrier sleeve a hub body of the wobble plate drive is mounted so as to be rotatable relative to the carrier sleeve but non-rotatable in relation to the intermediate shaft. In use, when a hammer bit in the tool holder is placed under load, the carrier sleeve and the intermediate shaft are caused to rotationally displace relative to each other as a result of the elastic coupling, wherein the inclination of the hub body of the wobble plate drive alters and with this the hammering stroke is altered.

Abstract: A power-driven impact drill includes a spindle extending at a right angle to the axis of rotation of a drill bit, a rotational first hammer slidably mounted on the spindle for co-rotation therewith, and a reciprocal second hammer slidably disposed in front of the drill bit. When the rotation of the first hammer is arrested by the second hammer, the first hammer is caused by a cam mechanism to retract along the spindle in a direction away from the second hammer against the force of a first hammer spring. Upon disengagement with the second hammer, the first hammer is permitted by the cam mechanism to slide back into engagement with the second hammer under the force of the first hammer spring while it is rotated by the spindle. In this instance, the angular velocity of the first hammer received by the spindle is enhanced by the force stored in the compressed first hammer spring so that a large impact power is imposed to the rotating drill via the second hammer without substantial loss.

Abstract: A portable, cordless battery-powered tool with a relatively small overall length is provided. A handle section forms the rearmost part of the tool. An electric motor is located below a spindle and forwardly of the handle section. The motor has a rotatable shaft located in parallel with the spindle. The handle section is provided with a switch trigger which is substantially aligned with the central axis of the spindle at its top.

Abstract: In a hand-held tool having a tool holder for receiving a variety of tool bits, a probing device is provided for checking the surface configuration of the shank of a tool bit inserted into the tool holder. The probing device includes at least one control element arranged to move radially inwardly through an opening in the tool holder. If the control element moves radially inwardly into an axially elongated recess in the tool bit shank, it moves out of stopping engagement with a slide permitting the slide to move relative to the control element and initiating a switching operation for changing the driving action of the hand-held tool.

Abstract: A rotary hammer has a pneumatic hammer mechanism which can be driven by means of a driver-part mounted rotatably on an intermediate shaft, with which driver-part a first coupling element of a coupling is non-rotatably connected, while the second coupling element of the coupling is non-rotatably mounted on the intermediate shaft and through axial displacement can be brought into positive coupling engagement with the first coupling element. A synchronizing arrangement is provided, which on approach of the coupling elements to one another, accelerates the first coupling element at least approximately to the rotational speed of the second coupling element and only then permits the positive engagement of the coupling elements.

Abstract: In a drilling device, a tool mounted in the device can be selectively switched from right-hand rotation to left-hand rotation. The tool can be connected to an output shaft on which two conical gear wheels are mounted in spaced relation so that they can be rotated in opposite directions around the output shaft. The teeth on the conical gear wheels face one another and are in meshed engagement with gear teeth on a drive shaft. A coupling part is slidably displaceably mounted on the output shaft and can be engaged with one or the other of the conical gear wheels. The coupling part is secured on the output shaft so that as it is rotated by one or the other conical gear wheels, in turn, it rotates the output shaft in the desired direction.

Abstract: A rotary hammer has a hammer body with an electric motor section which comprises a receiving section for receiving transmission mechanisms in a frame which serves as a shell barrel. A driving electric motor is installed in the shell barrel. The body also has a vibration and transmission mechanism section in which the transmission mechanisms including the motion conversion transmission mechanism and the vibrating mechanism are held by a bracket removably connected to the frame. In addition, the hammer body has a tool holding section in which the tool holding member for concomitantly rotatably holding the tool is rotatably supported by a bracket removably connected to the frame. The three sections are so arranged that they can be assembled and disassembled individually as separate component units.

Abstract: A hand-held electrically powered hammer tool with a rotor-type electromotor (17) and a hammer mechanism (14) arranged in a machine housing (13). The hammer mechanism (14) includes a drive shaft (24) with an excentric crank pin (35) thereon for a piston rod (43) connected to a drive piston (40) reciprocably movable in a cylinder (42) for driving a hammer piston (41) towards a working tool (16) via an air cushion (44) between the two pistons. The drive shaft for the hammer mechanism (14) is also the rotor shaft of the electromotor (17) so that the hammer mechanism and the motor are driven by the same speed. The electromagnetically active parts (23,49) of the rotor (18) are located outside of and surround the corresponding parts (21, 22) of the electromotor stator (19) thus enabling the rotor also to be a flywheel and a fanwheel.

Abstract: A hammer drill can be switched between combined rotary and impact operation and impact operation. An electropneumatic mechanism provides the impact force and includes a guide cylinder with a beveled gear wheel extending around the outside surface of the cylinder. The gear wheel is driven by a drive wheel. A coupling sleeve is mounted on the guide cylinder for rotation with it and is axially displaceable relative to the cylinder between a first position in meshed engagement with the gear wheel and a second position displaced out of meshed engagement. A switching device moves the coupling sleeve between the two positions. In the first position, the coupling sleeve rotates the guide cylinder, while in the second position the guide cylinder is locked against rotation. The switching device includes a control cam engaged within a groove extending in the circumferential direction of the outside surface of the guide cylinder.

Abstract: A rotary hammer has a reciprocating piston of a pneumatic impact mechanism driven from a rotatable drive shaft. A coupling element is fixed on, and a drive element slidably mounted on, the drive shaft. These elements have interengageble tapered coupling surfaces and are biased apart by a spring therebetween. The drive element is disposed forwardly of the coupling element and is slidable rearwardly to drivingly engage the coupling surfaces for transmitting drive to the piston. The relative disposition of the drive and coupling elements causes reaction force on the piston, consequential in use upon generation of percussive blows, to urge the drive element into intensified engagement with the coupling element.

Abstract: A power driven hammer drill includes a percussive mechanism connectable to driving gears via a clutch. A pressure amplifying lever system is arranged between a movable part of the clutch and shiftable guiding means for a work tool to apply an amplified pressure on the clutch when the work tool is pressed against a workpiece.

Abstract: A device for driving a drilling and/or impacting tool including a shaft journalled in a housing so as to be rotatable, if necessary. One end of the shaft is connectable with the tool whereas the other end is accessible for an oscillatory impact body movable in the housing by a guide, a rotatable driving shaft setting and a transmission. The transmission includes a device for converting the rotary movement of the driving shaft into an oscillatory movement of a driving element which is connected through an elastic member with the impact body.

Abstract: A hammer drill is provided with a clutch whose movable part is firmly connected to an axially displaceable drum which supports a wobbling disc driving a percussive mechanism for striking a work tool. The axially fixed clutch part is rotated by driving motor and is backed-up by a housing of the drill. Retroacting forces from the percussive mechanism are transferred via the drum onto the movable clutch part so that the engagement of the clutch is reinforced at the moment when the compression generated by percussive mechanism is maximum. When pressure applied on work tool is relieved, a separating spring disengages the clutch and braking surfaces on the drum limit its axial displacement and brake the rotation of the wobbling disc.

Abstract: Drilling or percussion hammer with an electric drive motor driving, preferably directly and without the use of any countershaft, a sleeve-like enlarged portion of the drive shaft leading to the tool holding fixture, with the entire striking mechanism being arranged within the said enlarged portion. The striking mechanism comprises a reciprocating driving piston whose cylindrical outer wall is provided with a closed, cam-like guiding groove which is engaged by a guide cam, preferably a driving ball, provided on the sleeve portion of the drive shaft which is driven in the rotary sense. The driving piston, which is permitted to move axially, but retained against rotation, derives the translatory movement of the driving piston directly from the torque supplied by the driving electric motor to the tool holding fixture, the driving piston accommodating in its interior in the conventional manner a striking piston which preferably is cushioned by an air cushion and which acts upon an anvil.

Abstract: An electropneumatic hammer drill includes a housing containing a guide cylinder in which an exciter piston and a percussion piston are displaceably mounted in spaced relation with an air cushion formed between them. A hollow shaft encircles the guide cylinder within the housing and transmits rotary motion to a tool mounted in the hammer drill. A crankshaft for reciprocating the exciter piston via a piston rod is supported in two bearings located in the guide cylinder. The percussion mechanism for the hammer drill made up of the guide cylinder, the exciter piston, the percussion piston, the crankshaft and the piston rod form a subassembly. The subassembly can be inserted into and removed from the hammer drill as a unit.

Abstract: A rotary hammer with a pneumatic impact mechanism carries on a drive shaft, non-rotatably and non-displaceable axially relative thereto, a coupling element as well as, rotatably and displaceable axially relative thereto, a drive element. The drive element has a peripheral drive fin constituting a cam/control curve which engages between two rollers. The rollers are mounted on the rear end of a piston of the pneumatic impact mechanism with their axes of rotation perpendicular to the longitudinal axis of the piston. The drive element can at choice be brought into engagement with the coupling element. A manually operable control member may be operated to maintain the drive element out of such engagement.

Abstract: The present invention provides multi-use-portable equipment, particularly suitable for driving rotating tools, as well as percussion and rotating tools, and percussion tools only. More specifically, it provides portable equipment driven by a small combustion engine which is connected to a tool post by a reduction gear engaged through a ventilated clutch. Depending on the requirement, the driven tool can be a rotating tool only, or a percussion tool, or a suitable combination of these two tools.

Abstract: A percussion tool such as a hammer head comprises a housing for receiving a tool. A rotary drive mechanism rotates the tool about a longitudinal axis. A strike bolt is arranged for impacting against the tool. A cylinder sleeve is mounted coaxially with the longitudinal axis. A piston is slidable within the sleeve and is arranged to impact against the strike bolt. An impact drive mechanism is provided for imparting sliding movement to the piston toward the strike bolt. The impact drive mechanism comprises a wobble drive member mounted for longitudinal reciprocal movement and for rotary movement about an inclined axis disposed at an acute angle relative to the longitudinal axis. The wobble drive member is operably connected to the cylinder sleeve and to the rotary drive means to be driven thereby about the inclined axis so as to be longitudinally reciprocated. Thus, the rotary forces and impacting forces are derived from the same source.

Abstract: A hammer tool with a drive motor (16) and a hammer mechanism (35), the hammer mechanism including a drive piston (38) reciprocably movable in a cylinder (34) for driving a hammer piston (39) towards a working tool (13) releasably coupled to the front end of the hammer tool. The hammer tool comprises a changeable motor section (11) containing the drive motor (16) with a motor shaft (19) connected to a first part of a coupling device (50) and a hammer section (12) containing the hammer mechanism (35). The hammer mechanism comprises bevel gears (46, 47) for transmitting drive force from an input drive shaft (45) to the drive piston (38). The input drive shaft is connected to a second part of the coupling device (50) in which a flywheel (48) is incorporated.

Abstract: Disclosed herein is a vibrator for use in a power drill having a housing and a spindle rotatably and axially movably supported by the housing. The vibrator comprises a rotary cam fitted on the spindle for rotation with the spindle, the rotary cam having a cam surface formed with at least one axially protruding ridge or serration; a clutch cam axially slidably fitted on the spindle and disposed behind the rotary cam, the clutch cam being restricted from rotating about the spindle and releasably engageable with the rotary cam, the clutch cam having a cam surface formed with at least one axially protruding ridge; and a spring adapted to urge the clutch cam toward the rotary cam so as to absorb the axial thrusting force applied to the spindle when the spindle is retracted.

Abstract: A hammer drill has a housing provided with a tool chuck in which a tool is to be mounted. A drive is provided which is capable of rotating and/or axially impacting the tool chuck. This drive includes a piston reciprocable in axial direction of the tool chuck, a drum rotating on a shaft extending parallel to the direction of reciprocation of the piston and provided with a circumferentially extending cam track, and a transmitting arrangement which travels in part in engagement with the cam track and which has another part connected with the piston to reciprocate the same.

Abstract: In an electropneumatic drill or chipping hammer with an air cushion transmitting driving force of an exciter piston to a percussion piston, a clutch is provided to interengage a drive motor with the exciter piston. The clutch can be selectively engaged by an axially displacing holding sleeve which positions a tool on the front end of the drill or hammer.

Abstract: A power tool has a changeover mechanism for varying at least one operational mode of the power tool. A rotatable control member having a lateral periphery is connected to the changeover mechanism. A detachable cover plate, forming part of the housing of the power tool, has an aperture therein through which the control member protrudes, and the lateral periphery of the control member is covered by the cover plate. A latching arrangement comprises a first latch component formed in said lateral periphery, and a second latch component located on the underside of the cover plate, the first and second latch components cooperating to retain the control member in a selected position, and one of these latch components is resilient. Preferably the second latch component is resilient and may be formed integrally with the cover plate. The cover plate may have two apertures for two control members with a common resilient latch member on the cover plate for both control members.

Abstract: An impacting drill is equipped with an air cushion impacting mechanism and with a tumbling mechanism which is operative for reciprocating the impacting mechanism. The tumbling stroke of the tumbling mechanism and thus the reciprocating stroke of the impacting mechanism is adjustable from zero to a maximum. The tumbling mechanism includes a hub body which is mounted on a holding body rigid with a rotatable shaft. The holding body is centered on an adjustment axis which encloses an acute angle with the axis of the shaft. The hub body is mounted on the holding body for angular displacement about the adjustment axis with attendant adjustment of the tumbling range. Coupling elements connect the hub body with the holding body in the respectively selected angularly displaced position of the hub body on the holding body.

Abstract: A power driven hammer drill has a tool impacting mechanism, a wobble unit for reciprocating the tool striking mechanism and having a drum member which can be releasably coupled with an intermediate shaft driven by a motor, wherein a switching device is provided outside of a hammer drill housing and arranged so as to disengage a coupling element of the intermediate shaft out of a coupling element of the drum member of the wobble unit against the action of a spring.

Abstract: A power operated tool includes a prime mover, an output member and a power transmission mechanism arranged to transmit rotary motion of the prime mover to a reciprocatory output member. The power transmission mechanism includes a first member mounted for reciprocating motion, a link coupled at one end to the first member, and a second member mounted for rotation about an axis transverse to the path of reciprocating motion of the first member. The arrangement is such that rotation of the second member reciprocates the first member and also imparts a cyclic partial rotation to the first member during said reciprocation. The second member has a bore therein spaced from the axis of rotation and inclined there towards. The bore has an axis which intersects the axis of rotation at an angle of about one quarter of the angle through which the first member partially rotates.

Abstract: A tool holder has a rotatable drive sleeve adapted to receive therein a tool and having a pair of diametrically opposed slots disposed axially along part of its length. A key extends inwardly into each slot and is movable through its sot for retaining and rotatably driving the tool. The slots have an axial length greater than that of the keys which are slidable axially there along. A locking collar, having an internal surface diverging progressively outwardly over at least a portion of its length in the axial direction, encircles the sleeve and is movable axially in one direction for locking the keys in engagement with the tool, and in the opposite direction to allow disengagement of the tool. The action of the divergent surface portion on the keys enables the keys to be locked in position over a range of inward penetrations to accommodate tools having driving recesses of different depths.

Abstract: A hammer drill is arranged to rotate and also apply percussive force to a tool receptacle. The percussive force is transmitted from a shaft to a drive piston which, in turn, reciprocates a percussion piston which drives the tool receptacle. The hammer drill includes a housing and a bearing rotatably mounted in the housing. The shaft is rotatably mounted in the bearing and its axis extends perpendicularly of the axis of rotation of the bearing. The bearing supports a contact rim which is in meshed engagement with the shaft. The contact rim is displaceably into frictional contact with a brake member for holding the contact rim against rotation while the bearing rotates carrying with it the shaft. Due to its meshed engagement with the contact rim, the shaft rotates about its own axis causing the drive piston to reciprocate.

Abstract: There is disclosed a combination rotary and percussive portable tool driven by an electric motor. The percussive tool includes a reciprocating cylinder having embodied therein a reciprocatable piston striker. The cylinder is mounted in a guide tube which is spring loaded by a spring positioned between an internal wall in the housing and a cap removably mounted over an opening of the housing. The opening provides access to the housing in order to remove the guide tube and spring. With the guide tube resiliently mounted in the housing, the guide tube and its interface with the housing is much less affected by the vibration and thermal conditions developed during operation of the tool. In addition, the tolerances required to mount the guide tube in the housing do not have to be kept as tight as they would have to be if a conventional mounting arrangement using welds or other rigid fastening devices were used.

Abstract: A portable electric hammer drill incorporates an electric motor 12 disposed close to the handle 13 of the tool and with its axis of rotation at right angles to the axis of rotation of the drill bit holder 10, and a gear 15 on the motor shaft meshes with a first pinion 16 driving the holder in rotation. A second pinion 25 meshes with the first pinion 16 and drives the driving piston 30 of the mechanism for transmitting impacts to the holder. The axes of rotation of the holder 10, the first and second pinions and the gear 15 ;are coplanar, and the first and second pinions are on diametrically opposite sides of the said gear, the first pinion being nearer the handle. This arrangement enables the motor to be placed nearer the handle than if the first pinion were in direct mesh with the said gear, and thus improves the balance of the tool. The arrangement permits the diameters of the first and second pinions to be selected independently of each other.

Abstract: A portable machine tool, especially a hammer drill, mainly comprises a housing in which a guide tube is arranged. A piston and a beater are guided in the guide tube reciprocatable in axial direction, the piston and the beater having facing axially spaced ends forming therebetween in the guide tube an air pillow through which the impact energy of the piston is transmitted to the beater. A turning sleeve coaxially surrounds the guide tube and is provided at its front end with a holding bushing formed with a coaxial bore therethrough in which a shaft of a tool, for instance a drill, is mounted for rotation therewith and for limited axial movement relative thereto. The beater is provided at the front end with a beater bolt having an outer diameter slightly smaller than the inner diameter of the bore so that the beater bolt, which transmits its impact energy directly to the free end of said tool shaft, may enter into the bore to be guided therein during reciprocation of the beater.

Abstract: A hammer drill has a motor-actuated drive piston and a free percussion body accommodated in a common, stationary cylinder. The percussion body is caused to move back and forth by the drive piston with air as the coupling and buffer medium. The hammer drill further has a tool holder driven by a hollow drive shaft which encloses the stationary cylinder and is driven by a motor which also actuates the drive piston.

Abstract: An impact drilling power tool has a housing, a spindle element mounted in the housing for rotation about an axis and for displacement in axial direction, and an impact element mounted in the housing for displacement axially toward and away from the spindle element. The impact element has an axially arranged extension coaxially received within a blind bore of the spindle element. The impact element has a plurality of cam surfaces provided on helical radial projections of the impact element, and rolling bodies of a cam follower element contact the respective cam surfaces and displace the impact element against the force of coaxial helical springs until encountering interruptions of the projections, upon which the springs rapidly displace the impact element toward the spindle element and an end face of the axial extension impacts the bottom of the blind bore. An output shaft of a driving motor drives a countershaft and via the same and meshing gears also the impact element and the spindle element.

Abstract: A hammer drill has a housing, a tool shaft rotatably and axially displaceably supported in the housing, a motor, a gearing connecting the motor with the tool shaft and a striking mechanism for imparting successive impacts to the tool shaft. The striking mechanism includes an axially movable striking element. The hammer drill further has a clutch component mounted on the tool shaft and having an engaged state in which it is operatively connected to the striking element and a disengaged state in which it is disconnected from the striking element, and a drive element connecting the motor with the clutch component to rotate the latter. The drive element and the clutch component are arranged axially slidably relative to one another. The striking mechanism further has an intermediate member supported next to and in axial alignment with the clutch component.

Abstract: A device for driving a drilling and/or impacting tool including a shaft journalled in a housing so as to be rotatable, if necessary. One end of the shaft is connectable with the tool whereas the other end is accessible for an oscillatory impact body movable in the housing by a guide, a rotatable driving shaft setting and a transmission. The transmission includes a device for converting the rotary movement of the driving shaft into an oscillatory movement of a driving element which is connected through an elastic member with the impact body.