EP1765556B1 - Percussion hammer and/or drill hammer comprising a safety coupling - Google Patents

Abstract

Disclosed is a safety coupling in a percussion hammer and/or drill hammer, comprising a basic sleeve (20), a driven toothed wheel (21) that is rotatably mounted on the basic sleeve (20) and can be driven by a drive unit, a closing ring (27) which is fastened to the basic sleeve (20), and a locking ring (28) located between the driven toothed wheel (21) and the closing ring (27). Said locking ring (28) is fixed in a torsion-proof manner relative to the closing ring (27) while being movable relative to the closing ring (27) in an axial direction, counter to the effect of a spring mechanism (29). The locking ring (28) is axially displaced while the driven toothed wheel (21) remains in the axial position thereof when a threshold torque is exceeded.

Description

The invention relates to a hammer drill and / or hammer drill according to the preamble of claims 1 or 5, which is equipped with a safety coupling. Such a hammer and / or hammer drill is from the DE-A-4215288 known.

In particular, when drilling consists of impact and / or rotary hammers (hereinafter referred to simply as hammers) the risk that the drill or drill bit abruptly jammed in the rock to be processed, resulting in a significant increase in the effective torque in the hammer and damage to the Drive train can lead. The torques must also be manually supported by the operator so that on heavier implements, a sudden blockage of the drill bit can cause the hammer to be torn from the operator's hand. For this purpose, a safety coupling is incorporated in the torque flow in known hammers, which interrupts the torque flow acting in the device when a predetermined limit torque is exceeded. As a result, an optionally excessive torque can no longer have a damaging effect on the drive or the operator.

The safety coupling can be arranged in various technical designs at different locations within the device in the force or torque flow, in particular in the torque flow between a drive of the hammer (eg an electric or internal combustion engine) and a tool-carrying tool holder. Fitting locations between a crankshaft belonging to the drive and a drilling shaft receiving or holding the tool holder have proven particularly suitable.

Safety clutches can be configured in many ways. In practice, so-called detent or claw-type safety clutches, which are arranged in the area of the drilling shaft or a percussion tube belonging to a striking mechanism of the hammer, have proved to be particularly advantageous. In this case, usually mounted on the drilling shaft or percussion tube, provided with frontal notches or claws drive gear by a clutch against a likewise provided with detents, integral with the percussion tube or the drilling shaft pressed federation. Such safety clutches are inexpensive to produce, robust and durable, since in the case of response, the rotational speeds are low and the installation site large diameter and enough space for a generous dimensioning is available.

Fig. 8 shows a section through a typical, z. B. off DE 101 45 464 A1 known hammer drill. The torque of an electric motor 1 serving as a drive is transmitted via a plurality of gears and a crankshaft 2 to a main shaft 3 and finally via further gears on a drilling shaft 4, which carries a tool holder 5, in turn inserted into a not shown drilling and / or chiselling tool can be.

In the main shaft 3, a safety coupling 6 is integrated, which has a supported by a spring 7 toothed disk 8. When a predetermined limit torque is exceeded 8 such large axial forces arise on the teeth of the toothed disc that the toothed disc 8 is pushed back against the action of the spring 7. An interruption of the torque flow is the result, so that a threat to the operator of the hammer, z. B. in a blocking of the drilling tool during a drilling process, is avoided.

From the DE 42 15 288 A1 a hammer drill is known with a safety coupling in which the arranged on the safety clutch drive gear must be axially displaced against the action of a spring to be brought out of engagement of mated with him mating gear and so to interrupt the flow of torque. As long as the hammer is new, this is not a problem. In the case of older devices, on the other hand, there is the risk that the drive gear wheel, after prolonged use, has run in such a way with the counter gear due to wear that it can no longer be displaced axially. But then a desired response of the safety clutch is not guaranteed when the limit torque is exceeded.

Rotary hammers are also often switch between several modes of operation: Except a pure drilling operation (with hammer mechanism off) and a hammer drill operation (drilling and chiseling) is also a pure chisel operation possible, in which the tool is not driven to rotate. In known hammers, however, the bit is then freely and uncontrollably rotatable, which can be unfavorable in the management of the entire device.

The invention has for its object to provide a hammer and / or rotary hammer with a safety coupling, which are improved in terms of wear resistance, reliability and functionality.

The object is achieved by a hammer and / or hammer drill according to claim 1 or according to claim 5. Advantageous embodiments of the invention are defined in the dependent claims.

The impact hammer and / or hammer drill according to the invention is equipped with a safety clutch, which can be driven by the drive torque with the drive gear, an axially arranged to the drive gear final ring over which the torque is feasible, and arranged between the drive gear and the locking ring locking device having. The latching device ensures a torque flow between the drive gear and the end ring in a normal operating state. In an overload condition in which a torque exceeding a predetermined limit torque is introduced into the safety clutch, the detent interrupts the torque flow between the drive gear and the end ring.

Due to the axial arrangement of drive gear and closing ring with the axially interposed latching device, it is possible to make the safety coupling such that at least the axial position of the drive gear must not be changed even in the overload condition. Rather, the locking device takes over the function of interrupting the torque closure by axial displacement.

The drive gear can always remain in its intended axial position and thus comb in case of overload with an associated mating gear. The occurring in the prior art problems of mutual run-in of drive gear and mating gear and the resulting limited reliability of the safety clutch is thereby avoided.

In a first embodiment of the invention, the latching device has a locking ring arranged between the drive gear and the closing ring. The locking ring is rotationally fixed relative to the closing ring and axially displaceable against the action of a spring device. The drive gear and the locking ring have an interlocking locking toothing, via which the torque to be transmitted from the safety clutch is conducted. In the normal operating state of the locking ring is pressed by the spring means axially against the drive gear, so that the locking teeth mesh. In the overload condition of the locking ring is axially displaced in the direction of the end ring against the action of the spring means, so that the locking teeth of locking ring and drive gear are disengaged.

A second embodiment of the invention provides a kinematic reversal of the embodiment described above. Thus, the latching ring disposed between the drive gear and the end ring is rotationally fixed relative to the drive gear and axially displaceable relative to the drive gear against the action of a spring means. The locking teeth are - in contrast to the embodiment described above - not formed between the drive gear and the locking ring, but between the closing ring and the locking ring. Accordingly, the closing ring has a latching toothing on an end face facing the latching ring, while the latching ring has a latching toothing which fits on the latching toothing of the closing ring on an end face facing the closing ring. The locking ring is no longer supported by the spring device against the end ring, but against the drive gear. In the normal operating state, the locking ring is pressed against the closing ring in such a way that the locking teeth mesh with one another. In the overload condition, however, the locking ring is axially displaced in the direction of the drive gear, so that the locking teeth are disengaged.

It is particularly advantageous to ensure that the axial position of the drive gear does not have to be changed if at least part of the latching device is axially movable relative to the closing ring and / or to the drive gearwheel. This can be z. B. realize that even only the locking device or a part thereof an axial movement - z. B. in overload condition - performs, while the other components of the safety clutch remain in their axial position.

Preferably, the axial position of the drive gear and / or the end ring is fixed at least in an axial direction. A movement of the drive gear or of the end ring in the opposite axial direction may be permissible under circumstances and then should only be possible against the action of a spring. As a result, various embodiments of the safety clutch are possible.

It when the drive gear and the end ring are arranged on a base sleeve is particularly advantageous. This design of the safety coupling enables a compact design, in which the safety coupling can be pre-assembled before installation in the hammer.

In a particularly advantageous embodiment of the invention, the drive gear is rotatably mounted on the base sleeve, while the closing ring is mounted on the base sleeve or formed einstükkig with the basic sleeve.

In another embodiment of the invention, this construction principle can be reversed, so that the closing ring is rotatably mounted on the base sleeve, while the drive gear is fixedly mounted on the base sleeve. Finally, a variant is possible in which both the drive gear and the closing ring are rotatably mounted on the base sleeve.

In a particularly advantageous embodiment of the invention, the locking teeth each have, viewed in the circumferential direction, oblique side edges over which the torque to be transmitted from the safety clutch is transmitted. Due to the oblique side edges, a directed against the action of the spring device axial force is constantly generated on the locking ring. When in the overload state, the effective torque exceeds the predetermined limit torque value, the axial force is so large that it axially displaces the locking ring against the action of the spring means in the direction of the end ring, so that the locking teeth are disengaged.

A particularly advantageous embodiment of the invention is that the closing ring and the locking ring each have driving claws that constantly interlock. As a result, the closing ring and the locking ring are rotationally fixed to each other in the circumferential direction. In the axial direction, however, the locking ring is displaceable relative to the closing ring. The driving claws can be made stable, so that they reliably transmit the torque, even when the locking ring is in its farthest position from the closing ring.

Preferably, the drive gear is axially supported or supported at least on a side remote from the locking claws side of the basic sleeve. In this way, a complex separate storage of the drive gear can be avoided. An axial bearing on the side of the locking claws, however, is not required because the drive gear is constantly supported on this side by the locking ring and the spring device acting behind it.

In a further advantageous embodiment of the invention, the basic sleeve is an integral part of the drilling or part of a percussion tube. This means that the basic sleeve does not necessarily have to be a separate, additional component. Rather, it is possible to build the drive gear, the end ring and the locking device on an already existing device in the hammer, namely in particular the drilling shaft, the percussion tube or another, arranged in the torque flux wave. However, a separate base sleeve has the advantage of a particularly simple pre-assembly outside of the hammer.

It is particularly advantageous that the safety coupling can be completely preassembled and then can be slid rotatably with its base sleeve onto a carrier sleeve. The carrier sleeve may be part of a drilling shaft and / or part of a striking mechanism or striking mechanism tube. In principle, the safety coupling according to the invention can be used in any type of impact hammer and / or hammer drill, so that the support sleeve can be used at a suitable location.

In a particularly advantageous embodiment of the invention is on the Support sleeve provided an axially displaceable switching ring, with which the torque flow from the safety coupling to the support sleeve can be made or interrupt. The switching ring is used to preset different operating states of the hammer, as explained in more detail below.

The switching ring is preferably rotatably connected to the support sleeve and has on a front side switching claws, which are assigned opposite, provided on a rear side of the closing ring shift dogs. The switching claws of the switching ring can thus be brought into engagement with the switching claws of the closing ring, so that the torque flow from the closing ring can be transmitted via the switching claws to the switching ring and from there to the carrier sleeve.

In a particularly preferred embodiment of the invention, the switching ring is displaceable at least between a drilling position in which the switching claws of the switching ring are engaged with the switching claws of the closing ring, and a free rotation position in which the switching claws are not engaged. In the drilling position, it is of course also possible for punches to be exerted on the tool by the impact mechanism provided in the hammer, so that the term "drilling position" also encompasses a "drilling bit position". In the free rotation position, however, no drilling torque is transmitted to the tool. Rather, then the tool can rotate freely relative to the hammer when the operator z. B. pivoted accordingly. Accordingly, the free rotation position is typically used prior to chiseling to bring a chisel blade into a suitable angular rotational position with the hammer housing.

In a particularly advantageous embodiment of the invention, the switching ring is displaceable in a fixing position (bit position), in the Fixierklauen, which are attached to the switching ring on a front side opposite the rear side, in opposite, provided on a housing fixing ring Fixierklauen be engaged. In the fixation position of the switching ring and consequently the carrier sleeve is thus fixed relative to the housing of the hammer. A rotation of the support sleeve or the drilling shaft and thus of the tool relative to the hammer is then excluded. The fixation position is used by the operator in clean chisel work (without drilling).

Fig. 1

einen Schnitt durch eine erfindungsgemäße Sicherheitskupplung für einen Schlag- und/oder Bohrhammer;

Fig. 2

eine perspektivische Explosionsdarstellung der Sicherheitskupplung von Fig. 1;

Fig. 3

die Explosionsdarstellung von Fig. 2 aus anderer Perspektive;

Fig. 4

einen Schnitt mit der auf ein Schlagwerkrohr gebauten Sicherheitskupplung;

Fig. 5

eine Außenansicht zu Fig. 4;

Fig. 6

eine perspektivische Explosionsdarstellung zu den Fig. 4 und 5;

Fig. 7

einen Schnitt durch eine andere Ausführungsform der erfindungsgemäßen Sicherheitskupplung; und

Fig. 8

einen Schnitt durch einen Schlag- und/oder Bohrhammer nach dem Stand der Technik.

These and other advantages and features of the invention are explained in more detail below by way of example with the aid of the accompanying figures. Show it:

Fig. 1

a section through a safety coupling according to the invention for a hammer and / or hammer drill;

Fig. 2

an exploded perspective view of the safety coupling of Fig. 1 ;

Fig. 3

the exploded view of Fig. 2 from another perspective;

Fig. 4

a section with the built on a striking tube safety coupling;

Fig. 5

an exterior view too Fig. 4 ;

Fig. 6

an exploded perspective view of the 4 and 5 ;

Fig. 7

a section through another embodiment of the safety coupling according to the invention; and

Fig. 8

a section through a hammer and / or hammer drill according to the prior art.

The Fig. 1 to 3 show a safety coupling according to the invention in a sectional or exploded view.

On a base sleeve 20, a drive gear 21 is arranged, which is supported with its smooth sliding surface 22 against a corresponding collar 23 of the basic sleeve 20. The drive gear 21 is freely rotatable relative to the base sleeve 20 and meshes with a counter-wheel, not shown, from which the drive torque of a drive, also not shown, is initiated. On one of the sliding surface 22 opposite end face 24, the drive gear 21 carries a plurality of radially offset Locking claws 25 a locking teeth 26 (see Fig. 2 ).

On the collar 23 opposite end of the base sleeve 20 is a closing ring 27 z. B. fixed by a press fit. Of course, the end ring 27 also attached elsewhere on the base sleeve 20, z. B. bolted or formed integrally with this.

Between the closing ring 27 and the drive gear 21, an axially displaceable locking ring 28 is arranged, which is pressed axially against the drive gear 21 by a plurality of springs 29 supported against the closing ring 27. The locking ring 28 carries a plurality of axially extending driving claws 30, which engage in corresponding grooves 31 between associated driving claws 32 of the closing ring 27. Accordingly, it is possible that the locking ring 28 is displaced axially by the springs 29 and against the action of the springs 29, wherein always the driving claws 30 of the locking ring 28 with the driving claws 32 of the end ring 27 remain engaged, so that a torque can be transmitted can.

The locking ring 28 carries on a drive gear 21 facing end side a plurality of locking claws 33, which form a locking teeth 34. The locking teeth 26 of the drive gear 21 and the locking teeth 34 of the locking ring 28 are formed such that the latching claws 25 and the latching claws 33 at least in a certain relative rotational position of the drive gear 21 and the locking ring 28 can engage with each other. The individual latching claws 25 and 33 can have a different or asymmetrical width in the circumferential direction (angular extensions), so that the latching claws 25, 33 can engage in each other less frequently than would be possible in principle on account of the number of intermediate spaces between the latching claws 25, 33. This avoids rattling of the safety coupling and reduces wear in the event of overload. On the other hand, due to the increased number of locking claws 25, 33 several locking points, so that the torque can be reliably transmitted.

The latching claws 25, 33 each have bevelled side edges 35, over which the force or torque flow between the drive gear 21 and the locking ring 28 is guided. Due to their inclination, the side flanks 35 each also generate axial forces, which are a Auseinanderdrükken of the drive gear 21 and the locking ring 28 effect. Since the drive gear 21 is supported against the collar 23, however, it can not shift axially, but always remains in the desired axial position, in which it meshes with the mating gear, not shown. The locking ring 28, however, is - as shown above - axially displaceable.

When the torque introduced into the drive gear 21 exceeds a predetermined limit value (limit torque), the axial forces caused by the inclined side flanks 35 become so great that the latching ring 28 is pressed against the action of the spring 29 in the direction of the end ring 27. As a result, the latching teeth 26 and 34 are disengaged, so that further transmission of the torque is avoided. The safety clutch is then in overload condition and performs its assigned function of protection of the driveline or the operator holding the hammer with his hands.

In the overload state, therefore, the locking ring 28 is pressed by the inclined side edges 35 against the end ring 27 such that the locking teeth 26 and 34 are disengaged. However, the springs 29 always push the locking ring 28 back to bring it into engagement with the locking teeth 26 of the drive gear 21. If the torque to be transmitted is still above the limit torque, the locking ring 28 experiences there again an increased axial force, which presses him back against the closing ring 27. Accordingly, the safety clutch will rattle in case of overload until the operator interrupts the operation of the hammer.

In the in the Fig. 1 to 3 In the embodiment shown, the springs 29 are to a considerable extent used in bores 36 formed essentially in the driving claws 32 of the closing ring 27. Alternatively, it is also possible that the springs 29 are inserted into corresponding holes in the driving claws 30 of the locking ring 28. This would even allow an increase in the axial width of the locking ring 28, which would improve its axial sliding properties on the base sleeve 20.

The in the Fig. 1 to 3 shown safety coupling is a self-contained assembly, which are pre-assembled outside the hammer can. The assembly can then be installed as a single component in a simple and comfortable way in the hammer.

The Fig. 4, 5 and 6 show the safety coupling in the installed state, that is pushed onto a support sleeve 40th Fig. 4 represents a section. In Fig. 5 is one to the cut of Fig. 4 matching side view pictured while Fig. 6 the arrangement in a perspective exploded view shows.

The carrier sleeve 40 may be part of a drilling shaft. In the in the FIGS. 4 to 6 As shown, the carrier sleeve 40 is a percussion tube, in the interior of which a per se known, not shown in the figures Luftfederschlagwerk is arranged. Air spring impactors are based on the principle that an axially reciprocating, z. B. on, a crankshaft driven drive piston back and forth drives a percussion piston lying in front of the drive piston via an air spring. The percussion piston in turn transfers its impact energy cyclically to a tool. Since such air spring impact are known in various configurations, a more detailed explanation is unnecessary.

If the carrier sleeve 40 is formed as a drilling shaft, they can record a full percussion, especially a percussion tube, or even - as in the 4 to 6 shown - the percussion tube or housing form.

In the in the 4 to 6 In the embodiment shown, it is necessary for the percussion tube to take over the function of a drilling shaft and, accordingly, to rotate in order to transmit the torque.

For this purpose, an axially displaceable switching ring 41 is disposed on the support sleeve 40, which is non-rotatably connected via wedges 42 with the support sleeve 40. The switching ring 41 is used for producing or interrupting the torque flow from the safety coupling to the support sleeve 40. On one end side of the switching ring 41 switching claws 43 are provided, which are assigned opposite, arranged on a rear side of the end ring 27 shift dogs 44. The shift dogs 44 are also in the Fig. 1 to 3 good to see.

In the in the 4 and 5 shown position of the switching ring 41, the switching ring 41 assumes a so-called "drilling position" in which the switching claws 43 of the switching ring 41 with the switching claws 44 of the end ring 27 are engaged, so that the introduced via the drive gear 21 torque via the end ring 27, the switching ring 41 and the spline 42 can be transferred to the carrier sleeve 40. From the support sleeve 40, the torque is transmitted in a manner not shown, but known per se to a likewise not shown tool.

If, in contrast, the switching ring 41 is displaced axially on the carrier sleeve 40 such that the switching claws 43, 44 are disengaged, a so-called "free rotary position" is achieved, in which no torque is introduced onto the carrier sleeve 40. Rather, the carrier sleeve 40 can rotate freely together with the switching ring 41.

Finally, a fixing ring 45 is provided, which is fixed to a housing, not shown, of the hammer. At the fixing ring 45 Fixierklauen 46 are frontally formed, which are assigned to 41 on a back side 47 of the switching ring 41 Fixierklauen 48. The switching ring 41 is accordingly displaceable in a fixation position, also not shown in the figures, in which the fixing claws 48 of the switching ring 41 are in engagement with the fixing claws 46 of the fixing ring 45. Although no torque is applied to the carrier sleeve 40 by the drive in this fixing position. However, the carrier sleeve 40 can not rotate freely because its position is fixed relative to the housing.

The axial displacement of the switching ring 41 is effected by means of an externally accessible by the operator lever 49, the z. B. can also be performed as a rotary switch, in particular in Fig. 6 shown. The rotational position of the shift lever 49 is transmitted via a shift eccentric 50 and a known switching spring 51 on a shift fork 52 which engages in a circumferential groove 53 in the outer region of the switching ring 41. By the switching spring 51, it is possible that in particular when z. B. the shift dogs 43 of the switching ring 41 are on the shift dogs 44 of the end ring 27, an axial force is applied to the shift dogs 43 so that they can finally engage 27 in a further relative rotation of the switching ring 41 relative to the end ring. For the Operator, this means an increased ease of use, since he can preselect the desired mode with the lever 49 and the device automatically - by the spring bias of the switching spring 41 - changes to the desired mode.

Fig. 7 shows another embodiment of the safety coupling according to the invention in a sectional view.

Since the safety coupling in the basic structure of the safety coupling of Fig. 1 has been used, the same reference numerals have been used for simplicity. In contrast, however, to the safety coupling of Fig. 1 the drive gear 21 is fixedly mounted on the base sleeve 20. The closing ring 27, however, is radially rotatable on the base sleeve 20. It is supported axially against the collar 23, wherein the action of the springs 29 secures the axial position of the end ring 27 against the collar 23. The springs 29 in turn are supported via the locking ring 28 against the drive gear 21 fastened to the base sleeve 20.

The further function of the safety coupling, in particular the latching device with the locking ring 28 and the springs 29 corresponds to the above with reference to the Fig. 1 to 3 explained principle, so that at this point a repetition is unnecessary.

In a further, not shown embodiment of the invention, both the drive gear 21 and the end ring 27 can be freely rotatably mounted on the base sleeve 20, wherein in each case a collar 23, as in the Fig. 1 and 7 shown, must be provided for each of the elements 21, 27. The springs 29 together with the locking ring 28 ensure that both the locking ring 27 and the drive gear 21 are each pressed against its associated collar 23, so that the respective axial position is ensured.

Although the safety clutches shown in the figures each have a base sleeve 20, it is not necessary for the embodiment of the invention to provide such a basic sleeve 20. Rather, it is also possible, the drive gear 21, the closing ring 27 and the locking ring 28 and the springs 29 having locking device without additional base sleeve 20 at a suitable location, for. B. build on the drilling shaft.

Claims (22)

1. Percussion hammer and/or hammer drill, having

   - a drive (1);

   - a drill shaft driven with torque by the drive; and having

   - a safety coupling disposed in the torque flux between the drive and the drill shaft;
   wherein the safety coupling comprises:

   - a driving toothed wheel (21) which can be driven with the torque by the drive (1);

   - a closing ring (27) disposed axially with respect to the driving toothed wheel (21), by means of which closing ring the torque can be controlled; and

   - a latching device (28, 29, 30) disposed between the driving toothed wheel (21) and the closing ring (27)

   wherein

   - in a normal operating condition the latching device (28, 29, 30) ensures a torque flux between the driving toothed wheel (21) and the closing ring (27); and wherein

   - in an overload condition, in which torque exceeding a predetermined limit torque is introduced into the safety coupling, the latching device (28, 29, 30) interrupts the torque flux between the driving toothed wheel (21) and the closing ring (27);

   characterised in that

   - the latching device has a latching ring (28) which is disposed between the driving toothed wheel (21) and the closing ring (27), can be displaced axially against the effect of a spring device (29) and ensures or interrupts the torque flux depending on the axial position;

   - the latching ring (28) is rotationally fixed relative to the closing ring (27) and is axially displaceable relative to the closing ring (27) against the effect of the spring device (29);

   - the driving toothed wheel (21) has latching teeth (26) on an end face (24) facing the latching ring (28);

   - on an end face facing the driving toothed wheel (21) the latching ring (28) has latching teeth (34) fitting with the latching teeth (26) of the driving toothed wheel (21);

   - in the normal operating condition the latching ring (28) is pressed by the spring device (29) axially against the driving toothed wheel (21) in such a way that the latching teeth (26, 34) engage in each other; and that

   - in the overload condition the latching ring (28) is axially displaced in the direction of the closing ring (27) and the latching teeth (26, 34) become disengaged.
2. Percussion hammer and/or hammer drill as claimed in claim 1, characterised in that

   - the latching teeth (26, 34) each comprise inclined side flanks (35) when seen in the peripheral direction, by means of which the torque to be transmitted by the safety coupling is transmitted from the driving toothed wheel (21) to the latching ring (28); and that

   - in the overload condition an axial force directed against the effect of the spring device (29) is produced by the inclined side flanks in such a way that the latching ring (28) is axially displaced in the direction of the closing ring (27) and the latching teeth (26, 34) become disengaged.
3. Percussion hammer and/or hammer drill as claimed in claim 1 or 2, characterised in that the closing ring (27) and the latching ring (28) each have entrainer claws (30, 32) which continually engage in each other in such a way that the closing ring (27) and the latching ring (28) are fixed to each other in the peripheral direction but can be displaced with respect to each other in the axial direction.
4. Percussion hammer and/or hammer drill as claimed in any one of claims 1 to 3, characterised in that the driving toothed wheel (21) is axially mounted, at least on a side facing away from its latching teeth (26), by a basic bushing (20).
5. Percussion hammer and/or hammer drill having

   - a drive (1);

   - a drill shaft driven with torque by the drive; and having

   - a safety coupling disposed in the torque flux between the drive and the drill shaft;

   wherein the safety coupling comprises:

   - a driving toothed wheel (21) which can be driven with the torque by the drive (1);

   - a closing ring (27) disposed axially with respect to the driving toothed wheel (21), by means of which closing ring the torque can be controlled; and

   - a latching device (28, 29, 30) disposed between the driving toothed wheel (21) and the closing ring (27)

   wherein

   - in a normal operating condition the latching device (28, 29, 30) ensures a torque flux between the driving toothed wheel (21) and the closing ring (27); and wherein

   - in an overload condition in which torque exceeding a predetermined limit torque is introduced into the safety coupling, the latching device (28, 29, 30) interrupts the torque flux between the driving toothed wheel (21) and the closing ring (27);

   characterised in that

   - the latching device has a latching ring (28) which is disposed between the driving toothed wheel (21) and the closing ring (27), can be displaced axially against the effect of a spring device (29) and ensures or interrupts the torque flux depending on the axial position;

   - the latching ring (28) is rotationally fixed relative to the driving toothed wheel (21) and is axially displaceable relative to the driving toothed wheel (21) against the effect of a spring device (29);

   - the closing ring (27) has latching teeth on an end face facing the latching ring (28);

   - on an end face facing the closing ring (27) the latching ring (28) has latching teeth fitting with the latching teeth of the closing ring (27);

   - in the normal operating condition the latching ring (28) is pressed by the spring device (29) axially against the closing ring (27) in such a way that the latching teeth engage in each other; and that

   - in the overload condition the latching ring (28) is axially displaced in the direction of the driving toothed wheel (21) and the latching teeth become disengaged.
6. Percussion hammer and/or hammer drill as claimed in claim 5, characterised in that

   - the latching teeth each comprise inclined side flanks (35) when seen in the peripheral direction, by means of which the torque to be transmitted by the safety coupling is transmitted from the latching ring (28) to the closing ring (27); and that

   - in the overload condition an axial force directed against the effect of the spring device (29) is produced by the inclined side flanks in such a way that the latching ring (28) is axially displaced in the direction of the driving toothed wheel (21) and the latching teeth become disengaged.
7. Percussion hammer and/or hammer drill as claimed in claim 5 or 6, characterised in that the driving toothed wheel (21) and the latching ring (28) each have entrainer claws (30, 32) which continually engage in each other in such a way that the driving toothed wheel (21) and the latching ring (28) are fixed to each other in the peripheral direction but can be displaced with respect to each other in the axial direction.
8. Percussion hammer and/or hammer drill as claimed in any one of claims 5 to 7, characterised in that the driving toothed wheel (21) is axially mounted, at least on a side facing away from the latching ring (28), by a basic bushing (20).
9. Percussion hammer and/or hammer drill as claimed in any one of claims 1 to 8, characterised in that at least part of the latching device (28, 29, 30) is axially moveable relative to the closing ring (27) and/or to the driving toothed wheel (21).
10. Percussion hammer and/or hammer drill as claimed in any one of claims 1 to 9, characterised in that the axial position of the driving toothed wheel (21) and/or of the closing ring (27) is fixed at least in an axial direction.
11. Percussion hammer and/or hammer drill as claimed in any one of claims 1 to 10, characterised in that the driving toothed wheel (21) and the closing ring (27) are disposed on a basic bushing (20).
12. Percussion hammer and/or hammer drill as claimed in claim 11, characterised in that

    - the driving toothed wheel (21) is rotatably mounted on the basic bushing (20); and that

    - the closing ring (27) is attached to the basic bushing (20) or is formed as one piece with the basic bushing (20).
13. Percussion hammer and/or hammer drill as claimed in claim 11, characterised in that

    - the driving toothed wheel (21) is rotatably mounted on, or fixedly attached to, the basic bushing (20); and that

    - the closing ring (27) is rotatably mounted on the basic bushing (20).
14. Percussion hammer and/or hammer drill as claimed in any one of claims 1 to 13, characterised in that the basic bushing (20) is an integral component of the drill shaft or part of a percussion tube.
15. Percussion hammer and/or hammer drill as claimed in any one of claims 1 to 14, characterised in that a support bushing (40) is provided, on which the safety coupling, in particular its basic bushing (20), is disposed in a rotatably moveable manner.
16. Percussion hammer and/or hammer drill as claimed in claim 15, characterised in that the support bushing (40) is part of the bore shaft.
17. Percussion hammer and/or hammer drill as claimed in claim 15 or 16, characterised in that the support bushing (40) is part of a percussion mechanism, in particular part of a percussion tube.
18. Percussion hammer and/or hammer drill as claimed in any one of claims 15 to 17, characterised in that an axially displaceable switching ring (41) is provided on the support bushing (40) in order to establish or interrupt a torque flux from the safety coupling to the support bushing (40).
19. Percussion hammer and/or hammer drill as claimed in claim 18, characterised in that the switching ring (41) is connected in a non-rotational manner to the support bushing (40) and comprises switching claws (43) on at least one end face, to which opposite switching claws (44) provided on a rear side of the closing ring (27) are allocated.
20. Percussion hammer and/or hammer drill as claimed in claim 19, characterised in that the switching ring (41) is displaceable at least between a drilling position, in which the switching claws (43) of the switching ring (41) are engaged with the switching claws (44) of the closing ring (27), and a free-rotation position in which the switching claws (43, 44) are not engaged.
21. Percussion hammer and/or hammer drill as claimed in any one of claims 18 to 20, characterised in that

    - the switching ring (41) comprises fixing claws (48) on a rear side (47) opposite the end face, to which opposite fixing claws (46) provided on a fixing ring (45) fixed to the housing are allocated; and that

    - the switching ring (41) is displaceable to a fixing position in which the fixing claws (48) of the switching ring (41) are engaged with the fixing claws (46) of the fixing ring (45).
22. Percussion hammer and/or hammer drill as claimed in any one of claims 18 to 21, characterised in that the switching ring (41) can be displaced by a switching device (49) which can be operated on an outer side of the percussion hammer and/or hammer drill.

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