Hammer mechanism

A hammer mechanism is provided, which has at least one impact-generation unit which includes a strike element, a clamping chuck drive shaft mounting the strike element in movable manner in the strike direction in at least one operating state, and a coupling unit which is connected to the clamping chuck drive shaft in torsionally fixed manner and provided to drive the impact-generation unit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a handheld machine tool having a hammer mechanism.

2. Description of the Related Art

Handheld machine tools which have an impact-generation unit, in which a hammer means is supported inside a hammer cylinder so as to be able to move are already known. The hammer cylinder, a clamping chuck and a wobble bearing of the impact-generation unit are driven by an intermediate shaft.

BRIEF SUMMARY OF THE INVENTION

A hammer mechanism is described, which has at least one impact-generation unit provided with a hammer means, a clamping chuck drive shaft mounting the hammer means in a manner that allows it to move in the strike direction in at least one operating state, and a coupling means, which is connected to the clamping chuck drive shaft in torsionally fixed manner and drives the impact-generation unit. An “impact-generation unit” in particular denotes a unit provided to translate a rotary motion into an, in particular, translatory strike motion of the hammer means which is suitable for drilling or impact drilling. In particular, the impact-generation unit is developed as an impact-generation unit considered useful by the expert, but preferably is implemented as a pneumatic impact-generation unit and/or, especially preferably, as an impact-generation unit having a rocker lever. A “rocker lever” in particular denotes a means that is mounted so as to allow movement about a pivot axis and which is provided to output power that was picked up in a first coupling area, to a second coupling area. A “hammer means” in particular denotes a means of the hammer mechanism that is meant to be accelerated by the impact-generation unit, in particular in translatory fashion, during its operation, and to output a pulse, picked up during the acceleration, in the direction of an inserted tool in the form of a strike pulse. The strike means preferably is supported by air pressure or, advantageously, by a rocker lever, such that it is able to be accelerated in the strike direction. Immediately prior to a strike, the strike means preferably is in a non-accelerated state. During a strike, the strike means preferably outputs a strike pulse in the direction of the inserted tool, in particular via a snap die. A “clamping chuck drive shaft” in particular denotes a shaft which transmits a rotary motion from a gearing, especially a planetary gearing, in the direction of a clamping chuck during a drilling and/or an impact drilling operation. Preferably, the shaft is at least partially developed as full shaft. The clamping chuck drive shaft preferably extends across at least 40 mm in the strike direction. In a drilling and/or in an impact drilling operation, the clamping chuck drive shaft and the clamping chuck have the same rotational speed, preferably always, i.e., no gear unit is provided on a drive train between the clamping chuck drive shaft and the clamping chuck. The term “clamping chuck” in particular denotes a device provided for the direct mounting of an inserted tool in at least torsionally fixed manner by a user, especially in a manner that is reversible without using a tool. A “strike direction” in particular denotes a direction that extends parallel to an axis of rotation of the clamping chuck and which runs from the strike means in the direction of the clamping chuck. The strike direction preferably is aligned parallel to an axis of rotation of the clamping chuck drive shaft. The term “mount so as to allow movement” specifically means that the clamping chuck drive shaft has a bearing surface which in at least one operating state transmits bearing forces to the strike means, in a direction perpendicular to the strike direction. A “coupling means” in particular denotes a means provided to transmit a motion from one component to another component at least by a keyed connection. The keyed connection preferably is designed to be reversible by the user in at least one operating state. In an especially preferred manner, the keyed connection is reversible for a switch between operating modes, i.e., advantageously between a screwing, drilling, cutting and/or an impact drilling operation. The coupling means in particular is developed as a coupling considered useful by the expert, but advantageously takes the form of a dog clutch and/or toothing. The coupling means advantageously includes a plurality of keyed connection elements and a region that connects the keyed connection elements. “In torsionally fixed manner” in particular means that the coupling means and the clamping chuck drive shaft are fixedly connected to each other in at least the circumferential direction, preferably in all directions, and, in particular, in all operating states. “Provided” in particular means specially configured and/or equipped. “Drive” in this context in particular describes that the coupling means transmits kinetic energy, especially rotational energy, to at least one region of the impact-generation unit. Preferably, the impact-generation unit uses this energy to drive the strike means. The development according to the present invention makes it possible to provide an especially compact and powerful hammer mechanism using constructively simple measures.

In addition, it is provided to develop the coupling means in one piece with the clamping chuck drive shaft, so that an inexpensive production is able to be realized. As an alternative or in addition, the coupling means could also be joined to the clamping chuck drive shaft in some other way that appears useful to the expert, but it is advantageously press-fitted, screw-fitted or joined in form-fitting manner in the circumferential direction and axially via a safety ring or a band. “In one piece” in particular means at least integrally, e.g., using a welding process, a bonding process, an injection-molding process or some other process considered expedient by the expert and/or is advantageously formed in one piece, for example by producing it from a casting and/or advantageously, from a single blank.

In another development, the coupling means dips into a coupling means of the impact-generation unit, at least when a strike mode is activated, which advantageously requires little design space. An “activation of a strike mode” in particular describes an adjustment process in which the operator in particular adjusts the hammer mechanism in such a way that the impact-generation unit drives the hammer means in a striking manner while operating. In the process, the operator preferably switches from a drilling and/or screwing mode into an impact drilling and/or cutting mode. “Dipping into a coupling means” in particular means that the coupling means is situated outside a recess of the impact-generation unit in one operating mode and is moved into the recess when the strike mode is activated. A “recess” in particular means a region delimited by the impact-generation unit which is enclosed by the coupling means over more than 180 degrees, advantageously more than 270 degrees, especially advantageously, over 360 degrees, on at least one plane which advantageously is aligned perpendicularly to the strike direction.

Furthermore, it is provided that the clamping chuck drive shaft penetrates the strike means at least partially, so that a clamping chuck drive shaft having an especially low mass and small space requirement is able to be realized. The phrase “penetrates at least partially” in particular means that the hammer means encloses the clamping chuck drive shaft over more than 270 degrees, advantageously over 360 degrees, on at least one plane that advantageously is oriented perpendicularly to the strike direction. Preferably, the hammer means is mounted on the clamping chuck drive shaft in form-fitting manner in a direction perpendicular to the axis of rotation of the clamping chuck drive shaft, i.e., supported in movable manner in the direction of the axis of rotation.

In addition, it is provided that the hammer mechanism includes at least one bearing, which mounts the clamping chuck drive shaft in axially displaceable manner and thereby provides a simple way of deactivating the hammer mechanism. A “bearing” in this context specifically describes a device which mounts the clamping chuck drive shaft especially in relation to a housing in a manner that allows movement about the axis of rotation and an axial displacement. The phrase “axial displacement” in particular means that the bearing mounts the clamping chuck drive shaft in a manner that allows it to move, especially relative to a housing, in a direction parallel to the strike direction. A connection of the coupling means of the clamping chuck drive shaft driving the impact-generation unit preferably is reversible by shifting the clamping chuck drive shaft in the axial direction.

It is furthermore provided that the hammer mechanism includes a planetary gearing which drives the clamping chuck drive shaft in at least one operating state, so that an advantageous translation is able to be achieved using little space. Moreover, a torque restriction and a plurality of gear stages are realizable by simple constructive measures. A “planetary gearing” in particular means a unit having at least one planetary wheel set. A planetary wheel set preferably includes a sun gear, a ring gear, a planetary wheel carrier and at least one planetary wheel which is guided along a circular path about the sun gear by the planetary wheel carrier. Preferably, the planetary gearing has at least two translation ratios, selectable by the operator, between an input and an output of the planetary gearing.

In one advantageous development of the present invention, the clamping chuck drive shaft has an additional coupling means, which is provided to produce an axially displaceable, torsionally fixed connection to the planetary gearing, so that a simple design is achievable. An “axially displaceable, torsionally fixed connection” in particular describes a connection provided to transmit a force in the circumferential direction and to allow movement of the clamping chuck drive shaft relative to the planetary gearing.

Furthermore, the hammer mechanism includes a torque-restriction device provided to restrict a torque that is maximally transmittable via the clamping chuck drive shaft, so that the operator is advantageously protected and the handheld tool is able to be used in a comfortable and safe manner for screw-fitting operations. “Restrict” in this context in particular means that the torque-restriction device prevents an exceeding of the maximal torque adjustable by an operator, in particular. The torque-restriction device preferably releases a connection between a drive motor and the clamping chuck, which is torsionally fixed during operation. As an alternative or in addition, the torque-restriction device may act on an energy supply of the drive motor.

Furthermore, the hammer mechanism has a clamping chuck and a snap die provided with a coupling means for transmitting a rotary motion to the clamping chuck, thereby creating an especially compact hammer mechanism. The snap die advantageously transmits a rotary motion of the clamping chuck drive shaft to the clamping chuck. A “snap die” in particular means an element of the hammer mechanism that transmits the strike pulse from the hammer means in the direction of the inserted tool during a strike operation. The snap die preferably strikes the inserted tool directly in at least one operating state. The snap die preferably prevents dust from making its way through the clamping chuck into the hammer mechanism.

In addition, the impact-generation unit includes a spur gear transmission stage which translates a rotational speed of the clamping chuck drive shaft into a higher rotational speed for impact generation, and thereby makes it possible in a space-saving and uncomplicated manner to achieve an especially advantageous ratio between the rotational speed and the number of strikes of an inserted tool. A “spur-gear transmission stage” in particular denotes a system of especially two toothed wheel works engaging with one another, which are mounted so as to be rotatable about parallel axes. On a surface facing away from their axis, the toothed wheel works preferably have gear teeth. A “rotational speed for strike generation” in particular is a rotational speed of a drive means of the impact-generation unit considered useful by the expert, which drive means translates a rotary motion into a linear motion. The drive means of the impact-generation unit preferably is developed in the form of a wobble bearing or, especially preferably, as an eccentric element. “Translate” in this case means that there is a difference between the rotational speed of the clamping chuck drive shaft and the rotational speed for the impact generation. The rotational speed for an impact generation preferably is higher, advantageously at least twice as high as the rotational speed of the clamping chuck drive shaft. Especially preferably, a translation ratio between the rotational speed for impact generation and the rotational speed of the clamping chuck drive shaft is a non-integer ratio.

Moreover, the hammer mechanism includes an impact-generation deactivation unit equipped with a blocking element which acts on the snap die, parallel to at least one force of the clamping chuck drive shaft, at least in a drilling operation and especially in a screwing operation, so that an advantageous placement of an operating element of the impact-generation deactivation unit is possible using measures that are uncomplicated in terms of design. In particular, an annular operating element, which encloses the snap die or the clamping chuck drive shaft, is easily able to be realized. In addition, this development requires little space. An “impact-generation deactivation unit” in particular means a unit provided to allow an operator to switch off the impact-generation unit for a drilling and/or screwing operation. The impact-generation deactivation unit preferably prevents an especially automatic activation of the impact-generation unit when an inserted tool is pressed against a workpiece in a drilling and/or screwing mode. The pressure application in a cutting and/or impact drilling mode preferably causes an axial displacement of the clamping chuck drive shaft. The blocking element is advantageously provided to prevent an axial displacement of the clamping chuck drive shaft, the clamping chuck and/or advantageously the snap die in the drilling and/or screw-fitting mode. “Parallel to a force” in particular means that the clamping chuck drive shaft and the blocking element apply a force to the snap die at two different locations in at least one operating state. As an alternative or in addition, the clamping chuck drive shaft and the blocking element are able to exert a force on the clamping chuck at two different locations in at least one operating state. The forces preferably have a component that is oriented in the same direction, i.e., preferably parallel to the axis of rotation of the clamping chuck drive shaft, from the clamping chuck drive shaft in the direction of the clamping chuck. The blocking element preferably acts on the snap die directly, but especially preferably, at least via a clamping chuck bearing. Preferably, the clamping chuck drive shaft is acting directly on the snap die. The snap die preferably transmits a rotary motion from the clamping chuck drive shaft to the clamping chuck.

Moreover, a handheld tool is provided, which includes a hammer mechanism according to the present invention. A “handheld tool” in this context in particular describes a handheld tool that appears useful to the expert, but preferably a drilling machine, an impact drill, a screw driller, a boring tool and/or an impact drilling machine. The handheld tool preferably is developed as a battery-operated handheld tool, i.e., the handheld tool in particular includes a coupling means provided to supply a drive motor of the handheld tool with electrical energy from a handheld tool battery pack connected to the coupling means.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows a handheld tool10a, which is developed as impact drill screwer. Handheld tool10ahas a pistol-shaped housing12a. A drive motor14aof handheld tool10ais situated inside housing12a. Housing12ahas a handle region16aand a battery coupling means18a, which is disposed at an end of handle region16afacing away from drive motor14a. Battery coupling means18alinks a handheld tool battery20a, which link is severable by an operator either electrically or mechanically. Handheld tool battery20ahas an operating voltage of 10.8 Volt, but could also have a different, especially higher, operating voltage. Furthermore, handheld tool10ais provided with a hammer mechanism22aaccording to the present invention, which includes a clamping chuck24adisposed on the outside, and operating elements26a,28a.

FIG. 2shows hammer mechanism22ain a sectional view. Hammer mechanism22aalso includes a planetary gearing30aand a clamping chuck drive shaft32a. When in operation, planetary gearing30adrives clamping chuck drive shaft32ain rotary motions about an axis of rotation. Planetary gearing30ahas three planetary gear stages34a,36a,38afor this purpose. An operator is able to adjust the transmission ratio of planetary gearing30abetween a rotor40aof drive motor14aand clamping chuck drive shaft32ain at least two stages. As an alternative, a transmission ratio between drive motor14aand clamping chuck drive shaft32acould also be designed to be non-adjustable.

Hammer mechanism22ais equipped with a torque restriction device42a. While in operation, torque restriction device42afixates a ring gear44aof planetary gearing30a. Torque restriction device42ahas fixation balls46afor this purpose, which engage with recesses of ring gear44a. A spring48aof torque restriction device42aexerts a force on fixation balls46a, in the direction of ring gear44a. Using one of operating elements26a, the operator is able to move an end of spring48afacing fixation balls46ain the direction of fixation balls46a. Operating element26aincludes an eccentric element for this purpose. Thus, the force acting on fixation balls46ais adjustable. If a particular maximum torque has been reached, fixation balls46aare pushed out of the recesses and ring gear44aruns freely, thereby interrupting a force transmission between rotor40aand clamping chuck drive shaft32a. Torque restriction device42athus serves the purpose of restricting a maximum torque transmittable via clamping chuck drive shaft32a.

Hammer mechanism22aincludes an impact-generation unit50aand a first coupling means52a. First coupling means52ais connected to clamping chuck drive shaft32ain torsionally fixed manner, first coupling means52aand clamping chuck drive shaft32abeing formed in one piece, in particular. Impact-generation unit50ais provided with a second coupling means54awhich is connected to first coupling means52ain torsionally fixed manner in a drilling and/or impact drilling mode. As shown inFIG. 3as well, first coupling means52aare developed as premolded shapes and second coupling means54aare developed as recesses. When the drilling mode is activated, first coupling means52adips into second coupling means54a, i.e., to the full extent. As a result, the coupling between first coupling means52aand second coupling means54ais reversible by axial shifting of clamping chuck drive shaft32ain the direction of clamping chuck24a. A spring56aof hammer mechanism22ais situated between first coupling means52aand second coupling means54a. Spring56apresses clamping chuck drive shaft32ain the direction of clamping chuck24a. When impact-generation unit50ais deactivated, it opens the link between first coupling means52aand second coupling means54a.

Hammer mechanism22ais provided with a first bearing58a, which fixates second coupling means54arelative to housing12ain the axial direction and rotationally mounts it coaxially with clamping chuck drive shaft32a. Furthermore, hammer mechanism22aincludes a second bearing60a, which rotationally mounts clamping chuck drive shaft32aon a side facing drive motor14a, such that it is able to rotate about the axis of rotation. Second bearing60ais developed in one piece with with one of the three planetary gear stages38a. Clamping chuck drive shaft32ais provided with a coupling means62a, which connects it to a planet carrier64aof this planetary gear stage38ain axially displaceable and torsionally fixed manner. As a result, this planetary gear stage38aserves the purpose of mounting clamping chuck drive shaft32ain axially displaceable manner. On a side facing clamping chuck24a, clamping chuck drive shaft32atogether with clamping chuck24ais rotationally mounted with the aid of a clamping chuck bearing70a. Clamping chuck bearing70ahas a rear bearing element which, axially fixated, is pressed onto clamping chuck24a. In addition, clamping chuck bearing70ahas a front bearing element which supports clamping chuck24ainside housing12ain axially displaceable manner.

Impact-generation unit50aincludes a spur gear transmission stage72a, which translates a rotational speed of clamping chuck drive shaft32ainto a higher rotational speed for impact generation. A first toothed wheel74aof spur gear transmission stage72ais integrally formed with second coupling means54a. In an impact drilling operation, it is driven by clamping chuck drive shaft32a. A second toothed wheel76aof spur gear transmission stage72ais integrally formed with a hammer mechanism shaft78a. An axis of rotation of hammer mechanism shaft78ais disposed next to the axis of rotation of clamping chuck drive shaft32ain the radial direction. Impact-generation unit50aincludes two bearings80a, which mount hammer mechanism shaft78ain axially fixed and rotatable manner. Impact-generation unit50aincludes a drive means82a, which translates a rotary motion of hammer mechanism shaft78ainto a linear motion. An eccentric element84aof drive means82ais integrally formed with hammer mechanism shaft78a. Using a needle roller bearing, for example, an eccentric sleeve86aof drive means82ais mounted on eccentric element84ain a manner that allows it to rotate relative thereto. Eccentric sleeve86ahas a recess88a, which encloses a rocker lever90aof impact-generation unit50a.

Rocker lever90ais pivotably mounted on a pivot axle92aof impact-generation unit50a, that is to say, it is able to pivot about an axis that runs perpendicularly to the axis of rotation of clamping chuck drive shaft32a. An end of rocker lever90afacing away from drive means82apartially encloses a strike means94aof hammer mechanism22a. In so doing, the rocker lever engages with a recess96aof strike means94a. Recess96ais developed in the form of a ring. In an impact drilling operation, rocker lever90aexerts a force on strike means94a, which accelerates it. Rocker lever90ais moved in a sinusoidal pattern while in operation. Rocker lever90ahas a spring-elastic design. It has a spring constant between eccentric sleeve86aand strike means94athat is less than 100 N/mm and greater than 10 N/mm. In this particular exemplary embodiment, rocker lever90ahas a spring constant of approximately 30 N/mm.

Clamping chuck drive shaft32amounts strike means94aso that it is movable in strike direction98a. Strike means94adelimits a recess100afor this purpose. Clamping chuck drive shaft32apenetrates strike means94athrough recess100a. In so doing, strike means94aencloses recess100ato 360 degrees in a plane perpendicular to recess100a. When operated, strike means94astrikes a snap die102aof hammer mechanism22a. Snap die102ais situated between an inserted tool104aand strike means94a. In the operative state, inserted tool104ais fixed in place in clamping chuck24a. Clamping chuck24amounts snap die102ain a manner that allows it to move parallel to strike direction98a. In an impact drilling operation, snap die102atransmits strike pulses originating from strike means94ato inserted tool104a.

Clamping chuck drive shaft32ais connected to snap die102ain axially movable and torsionally fixed manner. Snap die102adelimits a recess106afor this purpose. When in an operative state, clamping chuck drive shaft32ais partially situated inside recess106aof snap die102a. Clamping chuck drive shaft32ais rotationally mounted with the aid of snap die102a, clamping chuck24aand clamping chuck bearing70a. Clamping chuck24ais rotationally driven by way of snap die102a. Clamping chuck24aand snap die102aare each provided with a coupling means108a,110afor this purpose, the coupling means being provided to transmit the rotary motion to clamping chuck24a. Coupling means108aof snap die102ais developed in the form of a groove, whose main extension runs parallel to strike direction98a. Coupling means108aextends along a radially outward-lying surface area of snap die102a. Coupling means110aof clamping chuck24ais developed as a protrusion that fits the groove.

Clamping chuck24aincludes an inserted-tool coupling region112a, in which inserted tool104ais fixed in strike direction98aduring a drilling a screwing operation, or in which it is mounted in moveable manner in strike direction98aduring an impact-drilling operation. In addition, the clamping chuck includes a tapered region114a, which delimits a movement range of snap die102ain strike direction98a. Furthermore, clamping chuck24ais provided with a mounting ring116a, which delimits a movement range of snap die102acounter to strike direction98a.

During an impact drilling operation, an operator presses inserted tool104aagainst a workpiece (not shown further). The operator thereby shifts inserted tool104a, snap die102aand clamping chuck drive shaft32arelative to housing12a, in a direction counter to the strike direction98a, i.e., in the direction of drive motor14a. In so doing, the operator compresses spring56aof hammer mechanism22a. First coupling means52adips into second coupling means54a, so that clamping chuck drive shaft32abegins to drive impact-generation unit50a. When the operator stops pressing inserted tool104aagainst the workpiece, spring56ashifts clamping chuck drive shaft32a, snap die102aand inserted tool104ain strike direction98a. This releases a torsionally fixed connection between first coupling means52aand second coupling means54a, and thereby switches impact-generation unit50aoff.

Hammer mechanism22ahas an impact-generation deactivation unit118awhich includes a blocking element120a, a sliding block guide122a, and operating element28a. In a drilling or screwing mode, blocking element120aexerts a force on snap die102a, which acts on snap die102parallel to at least one force of clamping chuck drive shaft32a. The force of blocking element120aacts on snap die102avia clamping chuck bearing70a, clamping chuck24a, and mounting ring116a. The force of blocking element120aprevents an axial displacement of snap die102aand clamping chuck drive shaft32aduring a drilling and screwing mode, and thus prevents an activation of impact-generation unit50a. The force of clamping chuck drive shaft32ahas a functionally parallel component which drives snap die102ain rotating fashion during operation. In addition, the force has a functionally and directionally parallel component which is brought to bear on snap die102aby spring56avia clamping chuck drive shaft32a.

FIG. 4shows a section that runs perpendicularly to the section ofFIG. 2and parallel to strike direction98a, in which operating element28ais disposed in two different positions in the sections ofFIGS. 2 and 4. Operating element28ais developed in the form of a ring. It coaxially encloses the axis of rotation of clamping chuck drive shaft32a. Operating element28ais rotatable and connected to sliding block guide122ain torsionally fixed manner. Sliding block guide122ais likewise developed in the form of a ring. Sliding block guide122ais provided with a bevel124a. Bevel124aconnects two surfaces126a,128aof sliding block guide122a. Surfaces126a,128aare aligned perpendicularly to strike direction98a. Surfaces126a,128aare disposed in different planes in strike direction98a.

In an impact drilling mode, blocking element120ais situated inside a recess130a, which is delimited, for one, by bevel124aand one of surfaces126a. This surface126ais situated closer to drive motor14athan the other surface128a. Housing12ahas a housing element132a, which mounts the blocking element in torsionally fixed manner and allows it to move in strike direction98a. As a result, blocking element120a, together with clamping chuck24a, is able to be pressed in a direction counter to the strike direction98aat the start of an impact-drilling operation. In an impact-drilling operation, blocking element120adoes not exert any blocking force on clamping chuck24a. When operating element28aof impact-generation deactivation unit118ais rotated, blocking element120ais moved through bevel124ain strike direction98a. In the drilling or screwing mode, blocking element120ais kept in this frontal position. Blocking element120athereby prevents axial shifting of clamping chuck drive shaft32ain the drilling or screwing mode.

FIGS. 5 through 11show additional exemplary embodiments of the present invention. The following descriptions and the figures are essentially limited to the differences between the exemplary embodiments. Regarding components designated in the same way, particularly regarding components provided with identical reference numerals, it is basically also possible to refer to the drawings and/or the description of the other exemplary embodiments, especially ofFIGS. 1 through 4. In order to distinguish the exemplary embodiments, the letter a has been added after the reference numerals of the exemplary embodiment inFIGS. 1 through 4. In the exemplary embodiments ofFIGS. 5 through 11, the letter a has been replaced by the letters b through e.

FIG. 5shows a portion of a hammer mechanism22b. A hammer means94bof an impact-generation unit50bof hammer mechanism22bis mounted in movable manner on a clamping chuck drive shaft32bof hammer mechanism22b. Clamping chuck drive shaft32bis joined to a snap die102bof hammer mechanism22bin torsionally fixed and axially displaceable manner. Snap die102bis provided with a coupling means108bwhich forms a torsionally fixed connection to a clamping chuck24bof hammer mechanism22bin at least one operating state. Coupling means108bis situated on a side that is facing a tapered region114bof clamping chuck24b. Coupling means108bis developed as teething. A sealing region134bof the snap die is resting against clamping chuck24bwithout gear teeth and advantageously prevents dust from entering impact generation unit50b.

FIG. 6, likeFIG. 5, schematically illustrates a portion of hammer mechanism22c. A hammer means94bof an impact-generation unit50cof hammer mechanism22cis mounted in movable manner on a clamping chuck drive shaft32cof hammer mechanism22c. Clamping chuck drive shaft32cis joined to a snap die102bof hammer mechanism22cin torsionally fixed and axially displaceable manner. Snap die102cincludes a coupling means108cwhich forms a torsionally fixed connection to a clamping chuck24cof hammer mechanism22cin at least one operating state. Clamping chuck24chas an inserted-tool coupling region112c, in which coupling means108cof snap die102cat least partially engages. One inserted-tool coupling region112cis provided to exert forces on an inserted tool in the peripheral direction during operation. In an operative state, coupling means108cis at least partially disposed inside a tapered region114cof clamping chuck24c. Coupling means108cis developed in the form of an external hexagon. The dimensions of the external hexagon correspond to the usual dimensions of a bit for a screwing operation. A sealing region134cof the snap die102crests against clamping chuck24cwithout gear teeth and advantageously prevents dust from entering impact-generation unit50bin a cost-effective manner. Especially fat loss is able to be minimized.

FIGS. 7 through 10also show a portion of a hammer mechanism22das a section and a perspective view. A hammer means94dof an impact-generation unit50dof hammer mechanism22dis mounted in movable manner on a clamping chuck drive shaft32dof hammer mechanism22d. Clamping chuck drive shaft32dis joined to a snap die102dof hammer mechanism22din torsionally fixed and axially displaceable manner. Snap die102dincludes a coupling means108d, which in at least one operating state forms a torsionally fixed connection to a clamping chuck24dof hammer mechanism22d. In an operative state, coupling means108dis at least partially disposed inside a tapered region114dof clamping chuck24d. Coupling means108dis developed as teething and has two coupling ribs lying opposite each other in relation to the axis of rotation. Coupling means108dhas the same form and the same dimensions as a coupling means for the coupling with an insertion tool. The form and the dimensions correspond to those of the SDS Quick standard. A sealing region134dof snap die102drests against clamping chuck24dwithout gear teeth.

FIG. 11, likeFIG. 5, schematically illustrates a portion of hammer mechanism22e. A hammer means94eof an impact-generation unit50eof hammer mechanism22eis mounted in movable manner on a clamping chuck drive shaft32eof hammer mechanism22e. Clamping chuck drive shaft32eis joined to a snap die102eof hammer mechanism22ein torsionally and axially fixed manner. Clamping chuck drive shaft32eand snap die102eare developed in one piece. During a strike, hammer means94emoves both clamping chuck drive shaft32eand snap die102ein strike direction98e. With the aid of a coupling means62e, clamping chuck drive shaft32eis connected in axially displaceable and torsionally fixed manner to a planetary-gear stage described in the exemplary embodiment ofFIGS. 1 through 4.