WO2024126038A1

WO2024126038A1 - Hand-held electric power tool and method for operating a hand-held electric power tool

Info

Publication number: WO2024126038A1
Application number: PCT/EP2023/083448
Authority: WO
Inventors: Maximilian Knyrim
Original assignee: Hilti Aktiengesellschaft
Priority date: 2022-12-12
Filing date: 2023-11-29
Publication date: 2024-06-20
Also published as: EP4385664A1

Abstract

The present invention relates to a hand-held electric power tool (100), in particular a pressing, crimping and/or cutting tool, comprising a tool head (4) which is movable during operation of the hand-held electric power tool (100) and is coupled, or is able to be coupled at least temporarily, to a drive unit (10) via a linearly movably mounted actuating rod (3). The drive unit (10) has at least one drive motor (1) and a transmission (2) which converts a rotational drive of the drive motor (1) into a linear movement for driving the actuating rod (3). The drive unit (10) has a mechanical torque limiting device (5) which is designed to interrupt a force/torque flow from the drive motor (1) to the actuating rod (3) at a predetermined limit torque.

Description

Hilti Aktiengesellschaft

Principality of Liechtenstein

Hand-held electric power tool and method for operating a hand-held electric power tool

FIELD OF THE INVENTION

The present invention relates to a hand-held electric power tool, in particular a pressing, crimping and/or cutting tool, and to a method for operating a hand-held electric power tool.

Mechanical pressing, crimping and cutting processes are working steps frequently encountered on construction sites. When rebars need to be severed, pipes mechanically connected together (by crimping, flanging or squeezing, etc.) or hose clamps pressed on, pressing, crimping and/or cutting tools are used for this purpose. The simplest variant consists of purely manually operated devices such as bolt cutters and the like, but these have limited use in practice on account of the large actuating forces to be applied and the associated fatigue potential.

Therefore, electrically operated power tools which considerably simplify the execution of the pressing, crimping and cutting processes are widespread. In order to realize high actuating forces, for instance for crimping steel pipes, a pressing cylinder of one type of such tools is hydraulically driven. In this case, a drive motor drives a hydraulic pump, wherein a linear movement of the pressing cylinder is achieved using the hydraulic pressure generated by the hydraulic pump.

Another, likewise known type consists of electromechanical pressing, crimping and/or cutting tools, in which the actuating forces are transferred from the drive motor to the pressing or tool head not hydraulically but via a spindle drive. In this case, a rotational movement of the drive motor is converted into a linear movement via the spindle drive. These electromechanical devices frequently have a transmission, arranged between the spindle drive and the drive motor, for speed and torque conversion, in order for it to be possible for the drive motor to have an accordingly smaller and lighter design.

When the pressing or tool head of pressing, crimping and/or cutting tools has arrived in its action end position - in other words: when its jaws reach their limits - high hydraulic system pressures arise in a hydraulic pressing, crimping and/or cutting tool, and these pressures are released by means of a pressure relief valve in order not to mechanically overload the system.

Until now, electromechanically driven pressing, crimping and/or cutting tools have had only an electronic overload safety device, which switches off the drive motor when a predetermined limit power consumption is exceeded. This is comparatively sluggish and means that device components of the hand-held electric tool that are located in the force/torque flow are sometimes exposed to very high force and/or torque peaks. Therefore, these device components need to be slightly overdimensioned for resistance purposes in practice, this increasing the weight of the hand-held electric power tool and thus having a negative effect on the costs and on the ergonomics.

In hand-held electric screwdrivers, settable slip clutches mounted upstream of the tool head are known, via which a maximum torque is settable. However, such electric screwdrivers are not comparable to the hand-held electric power tool according to the invention, since these are fundamentally different types of tool; while an electric screwdriver comprises a rotationally driven tool head, the tool head of the hand-held electric power tool according to the invention is driven linearly.

It is an object of the present invention to provide an improved hand-held electric power tool, in particular a pressing, crimping and/or cutting tool, which is characterized by an optimized overload safety device and is thus more robust.

SUMMARY OF THE INVENTION

Accordingly, a hand-held electric power tool, in particular a pressing, crimping and/or cutting tool, is proposed, which comprises a tool head which is movable during operation of the hand-held electric power tool and is coupled, or is able to be coupled at least temporarily, to a drive unit via a linearly movably mounted actuating rod. The drive unit has at least one drive motor and a transmission which converts a rotational drive of the drive motor into a linear movement for driving the actuating rod. The drive unit also has a mechanical torque limiting device which is designed to interrupt a force/torque flow from the drive motor to the actuating rod at a predetermined limit torque.

The torque limiting device is advantageously a purely mechanically acting torque limiting device. This has the advantage that such a device reacts much more quickly than an electronically realized overload safety device of the drive motor. Force and/or torque peaks in the drive unit can therefore be avoided much more effectively than in known hand-held power tools of the generic type with only an electronic overload safety device. Since the maximum force and/or torque levels to be expected during operation are significantly reduced as a result, the overall drive train of the hand-held electric power tool can be designed to be weaker in terms of resistance, this having a positive effect on the weight of the hand-held electric power tool and thus, indirectly, also on the costs thereof and on improved ergonomics. During operation of the hand-held electric power tool according to the invention, the mechanical torque limiting device is activated virtually without delay as soon as the pressing or tool head has arrived in its action end position, or its jaws have reached their limits.

The predetermined limit torque can be designed individually in the dimensioning process of the hand-held electric power tool according to the invention, thereby ensuring that the drive train is not overloaded. In exemplary embodiments, the limit torque may be 10 to 100 Nm.

The application of the present invention is expressly not limited to pressing, crimping and/or cutting tools, but rather, the invention can be used universally for all hand-held electric power tools in which an actuating rod for actuating a tool head needs to be moved axially by means of a spindle drive, for instance also for glue dispensers, embossing tools and bending tools.

In embodiments, the drive motor may have a nominal speed of 8000 to 20 000 rpm.

According to one advantageous embodiment, the torque limiting device may have a defined press fit between a hub and a shaft of the transmission of the drive unit. Press fits can be designed reliably on the basis of the coefficients of friction, or surface roughnesses, that arise during functional contact and of the tolerance position, wherein a wide limit torque range is able to be realized. The further advantage also arises that a press fit is a very cost-effective embodiment of a mechanical torque limiting device, since its number of parts is reduced to the absolute minimum. Furthermore, a torque limiting device in the form of a press fit can be integrated in an extremely space-saving manner. The press fit is, according to the invention, designed specifically for transmitting a defined limit torque. In exemplary embodiments, the press fit can have a tolerance position of H7/k6 to H7/s6 or H6/k5 to H6/s6.

A suitable combination of materials in the press fit is in particular hardened steel on hardened steel or hardened steel on non-ferrous metal (for example copper, bronze or brass).

Alternatively, the torque limiting device may also comprise a slip clutch, wherein the slip clutch has in particular at least one spring element which generates a defined pressing force acting on a friction contact. A slip clutch affords the advantage that the limit torque is settable very precisely and that said slip clutch is also easy to maintain in the event of wear, since, in embodiments, friction linings of the friction contact can be replaced separately. Slip clutches are available on the market in a large number of shapes and sizes and for a wide range of limit torques, and so a person skilled in the art can choose a suitable variant. The slip clutch may be radially and/or axially active. In one exemplary embodiment, the slip clutch is embodied as a so-called tolerance ring. In embodiments, the slip clutch may be settable such that a user of the hand-held electric power tool according to the invention can set the desired limit torque directly on the device on the basis of a specific pressing, crimping and/or cutting task.

In a further embodiment, the transmission may have a spindle drive, wherein the spindle drive is coupled indirectly or indirectly to the drive motor on the input side and is coupled to the actuating rod on the output side.

The spindle drive is the device component of the transmission that converts the rotational movement of the drive motor into a linear movement, while the actuating rod is the device component of the hand-held electric power tool that transmits the linear feed forces and/or reverse forces to the tool head. A spindle drive affords the advantage that, via said spindle drive, a very large transmission ratio is able to be realized, such that very high linear forces are able to be generated using comparatively low drive torques.

According to yet another embodiment, the transmission may have a speed conversion device which is coupled to the drive motor on the input side and to the spindle drive on the output side. The speed conversion device may comprise in particular a planetary transmission, which combines a high transmission ratio, a high torque capacity and a low space requirement. The use of a speed conversion device coupled to the output side of the drive motor and mounted upstream of the spindle drive has the advantage that the drive motor can be dimensioned even smaller and thus lighter, this having a positive effect both in terms of costs and in terms of ergonomics.

In embodiments, a reduction ratio of the speed conversion device may be 8:1 to 50:1. A person skilled in the art can dimension a suitable reduction on the basis of the spindle pitch, the desired extension speed, the motor inertia, the device size and further factors.

In a further advantageous embodiment, the torque limiting device may be mounted upstream of the spindle drive on the input side and in particular be mounted downstream of the speed conversion device. This positioning of the torque limiting device within the drive unit or within the drive train has the particular advantage that, at this position, there are comparatively low speeds with a comparatively high torque level. This has an important positive effect on the wear behaviour of the torque limiting device, since when the latter is activated or “slips through”, relatively small relative movements occur as a result and so the tribological wear is minimized. In particular in embodiments in which the torque limiting device is embodied as a press fit, it is possible as a result for unintentional friction welding between the shaft and hub of the press fit to be effectively counteracted.

According to a further embodiment, the speed conversion device may be coupled to the spindle drive via a coupling element, wherein in particular the torque limiting device is integrated into the coupling element or connected thereto.

This embodiment affords the advantage that the integration of the torque limiting device is particularly space saving since, in particular, a device component that is already present in hand-held electric power tools of the generic type can be developed into a torque limiting device using structurally simple measures.

Advantageously, provision may be made for the coupling element to be coupled to the speed conversion device on the input side and to a rotatable device component of the spindle drive, in particular to a spindle of the spindle drive, on the output side.

Alternatively or additionally, the spindle drive may comprise at least one spindle nut in which the spindle is rotatably received, wherein the spindle nut is arranged in a relatively fixed position in particular with respect to the tool head. In embodiments, the spindle may be received in the spindle nut via at least one mounted rolling element. Preferably, the spindle drive is a rolling element screw, in particular a ball screw.

In embodiments, the coupling element may comprise a compensating coupling acting at least in an axial direction, in particular a torsionally rigid compensating coupling, in particular a spline shaft coupling or a claw coupling. In other words, it allows the coupling element to compensate for an axial offset which occurs as a result of the linear displacement of the spindle during operation of the spindle drive.

According to one development, the tool head may have at least two jaws that are each pivotable about a pivot point and are selectively openable and closable. The jaws each have at least one active face on mutually facing sides, this being able to be in particular a cutting face, a pressing die and/or crimping die. The jaws are coupled or able to be coupled at least temporarily kinematically to the actuating rod such that the respective opening or closing degree of the jaws depends on the linear position of the actuating rod. The kinematics of the jaws may be embodied in particular such that they are closed, or are able to be transferred into their action end position, during a feed movement of the actuating rod, while the jaws are opened during a return movement of the actuating rod.

Provision may also be made for the drive motor to be an electric drive motor which has in particular an overload safety device. The overload safety device may be in particular an electronic or electric overload safety device. In particular, the mechanical torque limiting device in this case has a quicker activation behaviour than the overload safety device of the drive motor. The overload safety device of the drive motor may be for example a protective circuit which interrupts the flow of current to the drive motor when a predetermined limit power consumption is exceeded.

Finally, the hand-held electric power tool may have a housing in or on which the tool head, the actuating rod and the drive unit are arranged. The housing may exhibit in particular a plastics material, or consist thereof. In embodiments, the housing may have an internal part made of a mechanically loadable material, in particular a metal, which acts as a machine carrier and accommodates the device parts that are involved in the force flow during operation. The housing, in particular the internal part thereof, provides corresponding accommodating regions for the tool head, the actuating rod and the drive unit, and is designed to accordingly absorb bearing forces that arise during operation.

A further aspect of the invention relates to a method for operating a hand-held electric power tool, wherein the hand-held electric power tool has a tool head which is movable during operation of the hand-held electric power tool and is coupled, or is able to be coupled at least temporarily, to a drive unit via a linearly movably mounted actuating rod. The drive unit has at least one drive motor and a transmission which converts a rotational drive of the drive motor into a linear movement for driving the actuating rod. Furthermore, the drive unit has a mechanical torque limiting device which is designed to interrupt a force/torque flow from the drive motor to the actuating rod at a predetermined limit torque. When the method is carried out

- the drive motor is operated to bring about a movement of the tool head in a direction of action, and

- the tool head is transferred into an action end position as a result, and

- if the predetermined limit torque in the drive unit is exceeded, the torque limiting device is activated in order to interrupt the force/torque flow from the drive motor to the actuating rod.

According to one development of the method, in a subsequent method step, an electronic overload safety device of the drive motor is activated.

BRIEF DESCRIPTION OF THE FIGURES

The following description explains the invention with reference to exemplary embodiments and figures, in which: Figure 1 shows a view in longitudinal section of a hand-held electric power tool according to the invention;

Figure 2 shows detail A according to Figure 1 ;

Figure 3 shows an isometric view of a coupling element, coupled to a spindle, of a hand-held electric power tool according to the invention with the torque limiting device in the drive state;

Figure 4 shows an isometric view of a coupling element, coupled to a spindle, of a hand-held electric power tool according to the invention with the torque limiting device in the activated state.

Identical or functionally identical elements are indicated by the same reference signs in the figures, unless stated otherwise.

EMBODIMENTS OF THE INVENTION

Figure 1 shows a view in longitudinal section of the hand-held electric power tool 100 in the form of a pressing, crimping and/or cutting tool. The hand-held electric power tool 100 has a movable tool head 4 with two jaws 41 that are each mounted so as to be pivotable about a pivot point 43. The jaws 41 are illustrated closed in the illustration but may be opened counter to the direction of action W in order to insert a workpiece to be worked, since, in the state shown, they are kept only loosely in the closed state by a pressure spring 46.

The jaws 41 each have an active face 42 on mutually facing sides, in particular in the form of a cutting edge, pressing die and/or crimping die. The workpiece to be worked, for instance a pipe segment to be crimped, can be introduced between the two active faces 42 after the jaws 41 have been opened by overcoming the preloading force of the pressure spring 46.

The hand-held electric power tool 100 also has a drive unit 10, which drives an actuating rod 3 that is able to be displaced linearly in an axial direction L and is able to be coupled kinematically to the jaws 41 of the tool head 4. During a feed movement of the actuating rod 3 in the longitudinal direction L, the jaws 41 can be loaded in the direction of action W, or in the closing direction, while the jaws 41 can be opened again during a return movement of the actuating rod 3. The actuating rod 3 is coupled to the tool head 4 via a connecting element 8 which is connected to a distal end of the actuating rod 3 by a screw connection 81. Arranged on the connecting element 8 are two rollers 44, which are mounted rotatably thereon. During a feed movement of the actuating rod 3, the rollers 44 come to bear on guide slots 45 that are respectively assigned to the jaws 41 , with the result that a closing force is exerted on the jaws 41.

The actuating rod 3 is mounted at its distal end via a radial bearing 31 with respect to the housing 6 or a mechanically loadable inner part of the housing, and sealed off via a seal 32. At its proximal end, the actuating rod 3 is mounted via a radial bearing 214 and an axial bearing 213 with respect to the spindle drive 21 , in particular with respect to a spindle 211 of the spindle drive 21.

The spindle drive 21 is part of a transmission 2 of the drive unit 10, which also has a drive motor 1 , in particular an electric motor. The drive motor 1 has a rotational action, wherein its output shaft is accommodated in a mounting 11 that mounts it with respect to the housing 6. The output shaft of the drive motor 1 is connected to a speed conversion device 22 which is provided in the form of a planetary transmission. An output side of the speed conversion device 22 is coupled to a coupling element 23 which has an outer part 233 and an inner part 232 which are connected together so as to rotate conjointly but to be axially displaceable. The speed conversion device 22 is coupled to the outer part 233 of the coupling element 23. At the other end, the coupling element 23 is coupled to the spindle drive 21 , namely via the inner part 232. The coupling element 23 represents a compensating coupling that acts in the axial direction and makes it possible to displace the inner part 232 in the longitudinal direction L relative to the outer part 233 coupled to the speed conversion device 22.

The inner part 232 of the coupling element 23 is coupled to a spindle 211 of the spindle drive 21 such that a rotational movement or a drive torque is able to be introduced into the spindle 211. The spindle 211 is guided rotatably in a spindle nut 212 which is arranged on the housing 6 in a fixed position with respect to the tool head 4. More specifically, the spindle 212 is accommodated in the spindle nut 212 via a multiplicity of mounted rolling elements 215. The rolling elements 215 are accommodated in particular in a rolling element cage. In other words, the spindle drive 21 is a rolling element screw. The spindle drive 21 is configured to convert a rotational movement of the coupling element 23 into a linear movement and to transmit the latter to the actuating rod 3. Since the spindle 211 is rotatable, the actuating rod 3 is uncoupled therefrom by the abovedescribed radial bearing 214 and axial bearing 213 such that the feed movement is transmitted to the actuating rod 3 but not the rotational movement.

The coupling element 23 is coupled to the spindle 211 of the spindle drive 21 via a mechanical torque limiting device 5. The mechanical torque limiting device 5 is embodied as a press fit between the inner part 232 of the coupling device 23 and the spindle 211 of the spindle drive 21. The press fit of the torque limiting device 5 is designed, with regard to its maximum transmissible limit torque, such that it is activated or slips through as soon as the jaws 41 of the tool head 4 have reached their limits. As a result, effective force or torque limitation is achieved in the entire drive unit 10 or in the drive train of the hand-held electric power tool 100, such that mechanical damage caused by overload can be reliably avoided. The arrangement of the torque limiting device 5 downstream of the speed conversion device 22 has the advantage that, at this position, there is a comparatively low speed level while there is a comparatively high torque level. These are ideal conditions for the use of a torque limiting device 5, since, when the latter is activated or slips through, only small relative movements occur, and so tribological wear and/or unintentional friction welding of the friction partners of the press fit is/are effectively counteracted.

Since the coupling of the spindle drive 21 to the actuating rod 3 is effective only in the feed direction or under pressure loading (the axial bearing 213 does not transmit any tensile forces), a restoring spring 7 is also provided, which pushes the actuating rod 3 back counter to the feed direction when the spindle drive 21 is moved back. The restoring spring 7 is supported on the housing 6 at one end and on a collar, projecting in the radial direction R, of the actuating rod 3 at the other end. By way of this very collar projecting in the radial direction R, the actuating rod 3 also bears on the axial bearing 213, such that the forces during the feed of the spindle 211 of the spindle drive 21 are introduced into the actuating rod 3 via this collar.

The housing 6 also has a battery receptacle 61 , at which a rechargeable battery for supplying the drive motor 1 with power can be exchangeably arranged. Figure 2 shows detail A in Figure 1. In this case, the functional core region of the handheld electric power tool 100 according to the invention is illustrated in more detail, wherein in particular the region of the coupling of the coupling element 23 to the spindle drive 21 via the torque limiting device 5 is more clearly apparent. Furthermore, the mounting 230, 231 of the coupling element 23 in the housing 6 is illustrated, which is realized via a ball bearing 230 and a roller bearing 231 , which are spaced apart in the longitudinal direction L.

Figure 3 and Figure 4 each show an isometric view of the coupling element 23 and of the spindle 211 of the spindle drive 21. As already stated herein, the outer part 233 of the coupling element 23 is connected as an assembly to an output side of the speed conversion device 22, while the inner part 232 is coupled to the spindle 211 of the spindle drive 21 via the torque limiting device 5. To be more precise, the torque limiting device 5 is in the form of a press fit between an outer lateral face of the inner part 232 of the coupling device 23 (“shaft side”) and an inner lateral face of the spindle 211 of the spindle drive 21 (“hub side”).

The coupling device 23 comprises an axially acting compensating coupling, which couples the outer part 233 to the inner part 232 for conjoint rotation but allows a relative axial movement of the inner part 232 with respect to the outer part 233 when the spindle 211 is axially displaced. The axial compensating action is realized via a spline shaft coupling 234 which is formed between an inner lateral face of the outer part 233 and an outer lateral face of the inner part 232. At its proximal end (on the left in the illustration), the outer part 233 has a radially inwardly protruding collar, which acts as an axial stop for the inner part 232.

Figure 3 illustrates a drive state, in which a drive-side rotation UA of the coupling element 23 corresponds to an output-side rotation Us of the spindle 211. By contrast, in Figure 4, the output-side rotation Us is prevented, specifically in that the jaws 41 of the tool head 4 have arrived in their action end position or have reached their limits. In this state, the maximum limit torque that is transmissible by the torque limiting device 5 is exceeded and so the latter is activated or slips through. The maximum torque or force level that arises in the drive unit 10 or in the drive train of the hand-held electric power tool is limited to the limit torque as a result and so no excessive force and torque peaks can arise during operation in a window of time between the jaws 41 reaching their limits and the activation of an overload safety device of the drive moor 1 .

Besides the possibility, already shown herein, of it being possible to design the compo- nents of the drive unit to be weaker in terms of resistance and thus of saving weight and costs, the further advantage also arises as a result of the hand-held electric power tool 100 being more robust and having a lower tendency to be damaged by mechanical overload.

LIST OF REFERENCE SIGNS

100 Hand-held electric power tool

10 Drive unit

1 Drive motor

11 Mounting output motor

2 Transmission

21 Spindle drive

211 Spindle

212 Spindle nut

213 Axial bearing actuating rod

214 Radial bearing actuating rod

215 Rolling elements

22 Speed conversion device

23 Coupling element

230 Mounting coupling element

231 Mounting coupling element

232 Inner part coupling element

233 Outer part coupling element

234 Spline shaft coupling

3 Actuating rod

31 Radial bearing actuating rod

32 Seal actuating rod

4 Tool head

41 Jaws

42 Active face/pressing die

43 Pivot point

44 Rollers

45 Guide slot

46 Pressure spring

5 Torque limiting device

6 Housing

61 Battery receptacle

7 Restoring spring

8 Connecting element actuating rod-tool head 81 Screw connection

L Axial direction

R Radial direction

UA Rotation drive coupling element Us Rotation output coupling element

W Direction of action

Claims

PATENT CLAIMS

1. Hand-held electric power tool (100), in particular pressing, crimping and/or cutting tool, comprising a tool head (4) which is movable during operation of the hand-held electric power tool (100) and is coupled, or is able to be coupled at least temporarily, to a drive unit (10) via a linearly movably mounted actuating rod (3), wherein the drive unit (10) has at least one drive motor (1) and a transmission (2) which converts a rotational drive of the drive motor (1) into a linear movement for driving the actuating rod (3), characterized in that the drive unit (10) has a mechanical torque limiting device (5) which is designed to interrupt a force/torque flow from the drive motor (1) to the actuating rod (3) at a predetermined limit torque.

2. Hand-held electric power tool (100) according to Claim 1 , wherein the torque limiting device (5) has a defined press fit between a hub and a shaft of the transmission (2) of the drive unit (10).

3. Hand-held electric power tool (100) according to Claim 1 , wherein the torque limiting device (5) comprises a slip clutch, wherein the slip clutch has in particular at least one spring element which generates a defined pressing force acting on a friction contact.

4. Hand-held electric power tool (100) according to one of Claims 1 to 3, wherein the transmission (2) has a spindle drive (21), and wherein the spindle drive (21) is coupled indirectly or indirectly to the drive motor (1) on the input side and is coupled to the actuating rod (3) on the output side.

5. Hand-held electric power tool (100) according to Claim 4, wherein the transmission (2) has a speed conversion device (22) which is coupled to the drive motor (1) on the input side and to the spindle drive (21) on the output side, wherein in particular the speed conversion device (22) comprises a planetary transmission.

6. Hand-held electric power tool (100) according to Claim 4 or 5, wherein the torque limiting device (5) is mounted upstream of the spindle drive (21) on the input side, and in particular is mounted downstream of the speed conversion device (22).

7. Hand-held electric power tool (100) according to Claim 5 or 6, wherein the speed conversion device (22) is coupled to the spindle drive via a coupling element (23), wherein in particular the torque limiting device (5) is connected to the coupling element (23) or is integrated into the coupling element (23).

8. Hand-held electric power tool (100) according to Claim 7, wherein the coupling element (23) is coupled to the speed conversion device (22) on the input side and to a rotatable device component of the spindle drive (21), in particular to a spindle (211) of the spindle drive (21), on the output side.

9. Hand-held electric power tool (100) according to one of Claims 4 to 8, wherein the spindle drive (21) comprises at least one spindle nut (212) in which the spindle (211) is rotatably received, wherein in particular the spindle nut (212) is arranged in a relatively fixed position with respect to the tool head (4).

10. Hand-held electric power tool (100) according to one of Claims 7 to 9, wherein the coupling element (23) comprises a compensating coupling acting at least in an axial direction, in particular a torsionally rigid compensating coupling, in particular a spline shaft coupling (234) or a claw coupling.

11. Hand-held electric power tool (100) according to one of the preceding claims, wherein the tool head (4) has at least two jaws (41) that are each pivotable about a pivot point (43) and are selectively openable and closable, wherein the jaws (41) each have at least one active face (42) on mutually facing sides, in particular a cutting face, a pressing die (42) and/or crimping die.

12. Hand-held electric power tool (100) according to one of the preceding claims, wherein the drive motor (1) is an electric drive motor which has in particular an electronic overload safety device, wherein the torque limiting device (5) has in particular a quicker activation behaviour than the overload safety device of the drive motor (1).

13. Hand-held electric power tool (100) according to one of the preceding claims, wherein the hand-held electric tool (100) has a housing (6) in or on which the tool head (4), the actuating rod (3) and the drive unit (10) are arranged.

14. Method for operating a hand-held electric power tool (100), in particular a pressing, crimping and/or cutting tool, in particular according to one of the preceding claims, wherein the hand-held electric power tool (100) comprises a tool head (4) which is movable during operation of the hand-held electric power tool and is coupled, or is able to be coupled at least temporarily, to a drive unit (10) via a linearly movably mounted actuating rod (3), wherein the drive unit (10) has at least one drive motor (1) and a transmission (2) which converts a rotational drive of the drive motor (1) into a linear movement for driving the actuating rod (3), and wherein the drive unit (10) has a mechanical torque limiting device (5) which is designed to interrupt a force/torque flow from the drive motor (1) to the actuating rod (3) at a predetermined limit torque,

- wherein the drive motor (1) is operated to bring about a movement of the tool head (4) in a direction of action (W), and

- the tool head (4) is transferred into an action end position as a result, and

- if the predetermined limit torque in the drive unit (10) is exceeded, the torque limiting device (5) is activated in order to interrupt the force/torque flow from the drive motor (1) to the actuating rod (3).

15. Method according to Claim 14, wherein an electronic overload safety device of the drive motor (1) is activated.