DE102015103903B4 - Power wrench with direct angle and/or torque measurement - Google Patents

Abstract

Torque support (3, 5, 9) of a device (20) for pneumatically or hydraulically driving a shaft (11, 12) comprising a tool holder and a housing (1), wherein the torque support (3, 5, 9) can be connected in a rotationally fixed manner to at least one section of the housing for receiving a reaction torque and has at least one sensor (4, 10, 13) for determining a reaction torque, which is connected to a signal processing device (7), wherein at least the torque support (3, 5, 9) and/or the shaft that can be received in the torque support forms a reaction element which forms at least one stress line during operation of the device (20), characterized in that the sensor (4, 10, 13) detects at least one change in length in a region of the at least one stress line, preferably in the region of the maximum stress lines of the reaction element (3, 5, 9) during operation of the device (20) and by means of the signal processing device (7) and predetermined Parameters determine an action torque of the shaft (11, 12) in the area of the tool holder.

Description

The present invention relates to a power screwdriver with a torque arm, in which essential screwing parameters are determined independently by means of direct angle of rotation and/or torque measurement, or a torque arm with at least one sensor for directly determining a torque of a power screwdriver.

Power screwdrivers are well known in the art. They are used to screw in or loosen screws using a shaft (drive shaft) at the end of which a tool holder is arranged. Power screwdrivers are used in particular for large machines or systems. Torques in the range of several thousand Newton meters often occur on the shaft.

Hydraulic or pneumatic screwing tools in particular are controlled indirectly according to the state of the art. With indirect control (according to the definition in VDI/VDE Guideline 2862 Sheet 2), the hydraulic (or pneumatic) pressure of the energy supply - usually measured at the pressure source - is used to calculate the target torque value on the shaft. In the following, we will mostly talk about hydraulic devices. However, this implies that the devices and methods according to the invention can also be applied in an analogous manner to pneumatic devices and methods.

Such a device with indirect control has the following disadvantages, among others: Particularly at higher flow rates of the hydraulic fluid, a systematic measurement error arises due to the back pressure. Therefore, in the state of the art - in order to make these systems sufficiently accurate - relatively low flow rates are usually used in order to keep the back pressure low and thus achieve the required precision.

A particular difficulty arises with so-called intermittently operating hydraulic tools. These are typically used with tools that have a ratchet function. With such power wrenches, the end of the tool's stroke is reached quite frequently, namely with each ratchet step. With power wrenches with indirect control, the hydraulic pressure continues to rise without a further increase in torque.

In other devices according to the state of the art, the angle of rotation of the shaft is also required as a measurement value. For example, in devices that work according to the so-called torque-angle of rotation method, the angle of rotation of the shaft (tool spindle) is used; this method enables tightening in the elastic and over-elastic range. Another example is the so-called gradient method, which enables yield point-controlled tightening. According to the state of the art, the angle of rotation of the shaft is measured via a flow sensor, i.e. indirectly, which also leads to a high degree of inaccuracy when determining the angle of rotation.

EP 0 042 548 B1 shows a screwing device with torque determination. The invention relates to a screwing device with torque determination, with a drive device arranged in a housing, the output shaft of which protrudes from the housing, a support foot coupled to the housing via an elastic connecting device and longitudinally movable along a sleeve with a non-circular profile for holding the housing against rotation and with a device for determining the screwing torque by determining the support torque acting on the support foot.

EN 25 20 250 A1 relates to a support device for gearbox wrenches for preventing the gearbox housing from rotating when a torque is transmitted from the input shaft to the output shaft of the gearbox, consisting of a holder which can be mounted on the gearbox housing in a rotationally fixed manner and which can be attached with an arm against a fixed point.

WO 2003/ 006 208 A1 relates to a power wrench with electronic torque limitation, with a drive unit and a downstream planetary gear that contains a planetary gear carrier. For this purpose, a combination of torque detection and rotational position detection is provided for follow-up control.

EN 43 07 131 A1 relates to a pressure-operated hydraulic or pneumatic power wrench with a drive part and a functional part, wherein the functional part has a shaft driven by a ratchet lever, which has a driving device, and with a measuring section determining the torsion element.

DE 202 13 740 U1 relates to an electric lifting cylinder which has a control device for a load-dependent force limitation and which, when a limit value of the torque is exceeded, switches off the drive of the electric lifting cylinder, reverses it or reduces the drive force, whereby the electric lifting cylinder is not damaged even in the event of an overload.

EN 10 2015 000 555 A1 relates to a screwdriver with a motor for generating a torque, furthermore with a tool holder which is in operative engagement with the motor and transmits the generated torque to a tool, a measuring device which continuously measures at least one measured variable for determining the torque and forwards the measured value, and with a control device which is connected to the motor and the measuring device and controls the operation of the motor in such a way that it generates a continuously increasing torque after it has been started, and which switches the motor off when a target measured value is reached.

Against this background, the object of the present invention is to provide a power wrench that at least partially overcomes or improves the disadvantages of the prior art described above. In addition, a torque support with a sensor system for determining the torque on a reaction element of the power wrench is also provided, which can be connected to a power wrench known in the prior art and thus at least partially overcomes or improves the disadvantages known in the prior art.

These and other objects are achieved by a torque support and a power screwdriver according to independent claims 1 and 2 and a method according to independent claim 8. Embodiments and developments of the present invention are the subject of the subclaims.

A device according to the invention for pneumatically or hydraulically driving a shaft with a tool holder has at least one torque support and a housing, wherein the torque support can be connected in a rotationally fixed manner to at least one section of the housing. This section of the housing serves to absorb a reaction torque. At least one sensor for determining a reaction torque is arranged in this section of the housing. This sensor is connected to a signal processing device. At least the torque support and/or the driven shaft forms a reaction element which has at least one stress line in the device during operation.

The sensor is arranged in an area of the at least one stress line, preferably in the area of the maximum stress lines of the reaction element such as the torque support, and detects at least one change in length in the measuring field during operation of the device. Based on this change in length and predetermined parameters, the signal processing device, which is connected to the sensor, determines an action torque of the shaft in the area of the tool holder.

The present invention includes both the combination of a power wrench in the form of a device for pneumatically or hydraulically driving a shaft with a torque arm equipped with corresponding sensors, as well as a torque arm per se, which, due to its inventive design with corresponding sensors, is suitable for working together with a corresponding power wrench known in the prior art.

The torque support according to the invention for a device for pneumatically or hydraulically driving a shaft with a tool holder and a housing can be connected in a rotationally fixed manner to at least one section of the housing of the device for absorbing a reaction torque and has at least one sensor for determining a reaction torque, which is connected to a signal processing device. At least the torque support and/or the shaft that can be accommodated in the torque support form a reaction element that forms at least one stress line in the device during operation. During operation of the device, the sensor detects at least one change in length in an area of the at least one stress line, preferably in the area of the maximum stress lines of the reaction element, and determines an action torque of the shaft in the area of the tool holder by means of the signal processing device and predetermined parameters.

In combination, the device for pneumatic or hydraulic drive comprises a shaft with a tool holder, a housing, a torque arm, which is connected to at least a section of the housing for receiving a reaction torque, and at least one sensor for determining a reaction torque, which is connected to a signal processing device. At least the torque arm and/or the shaft form a reaction element, which has at least one stress line during operation. The sensor detects at least one change in length in an area of the at least one stress line, preferably in the area of the maximum stress lines of the torque arm and/or shaft, i.e. a reaction element, during operation of the device and determines an action torque of the shaft in the area of the tool holder by means of the signal processing device and predetermined parameters.

A torque support according to the invention is understood to be a component that absorbs the reaction force, for example when a screw is screwed in, by means of a shaft. Such a component can, for example, be designed in one embodiment as a type of reaction arm, which is arranged, for example, to the side of the housing, preferably axially to the action shaft, and can be connected to it in a rotationally fixed manner. In another embodiment, it can be designed as a reaction sleeve, which is arranged, for example, around the rotary shaft. This is supported on the housing or a machine element (component for absorbing the reaction force) and, on the opposite side, engages in a structure connected to the element to be screwed in a force-fitting manner. Such a structure can, for example, be a profiled washer that protrudes beyond the screw head to be tightened and on the top of which the force-fitting connection with the torque sleeve is provided and on the other side a friction-fitting connection with the element to be screwed in is provided. Such systems are known in the prior art.

Such a torque support must absorb a significant (the same when used as intended) part of the reaction force caused by the action torque of the shaft. This causes torsion of the shaft or torque support, and stress lines form in and on the shaft or torque support. Length changes can be determined along these stress lines and recorded using a suitable sensor. The length changes are a function of the reaction torque. In the simplest case, this function can be a proportional relationship between reaction torque and length change.

A signal processing device according to the invention is understood to be a controller or a similar computer which calculates a target torque for the shaft from the measured values of the sensor or sensors, with which the pneumatic or hydraulic drive is controlled.

A pneumatic or hydraulic drive according to the invention is understood to be a pressure source, for example a hydraulic pump or a compressor. This pressure source can be controlled via a suitable interface. The target torque of the shaft (action torque) is selected as the control variable.

With a device according to the invention for direct measurement of torque, a systematic measurement error that is caused by the dynamic pressure in indirect control according to the state of the art is avoided. Furthermore, work can be carried out more precisely and with higher dynamic pressure and thus faster than with indirect control. A device according to the invention therefore also achieves higher values in machine capability tests (MFU) in accordance with VDI/VDE Guideline 2645 Sheet 2. A device according to the invention can also be approved for screw systems in safety category A in accordance with VDI/VDE 2862 Sheet 2. A core statement of the guideline is that for screwing cases with a high risk assessment, only those screw systems that have the direct measurement of angle of rotation and/or torque are classified as suitable.

The advantages of the invention are particularly evident in intermittently operating hydraulic tools. The end of the tool's stroke is clearly identified with each ratchet step. The screws can therefore be tightened with greater precision and therefore more safely.

In an embodiment according to the invention, the torque support is a support foot or reaction arm that extends at least partially around the shaft or, in particular, a sleeve. The embodiments mentioned are connected in a rotationally fixed manner to the housing of a shaft or the device and interact with a further counter bearing in the area of a screw connection.

In one embodiment, the pressure source can be part of a tool that is indirectly controlled according to the prior art. In this case, a device according to the invention is placed on the shaft of the indirectly controlled tool and the pressure source (or the energy supply) is controlled by means of the signal processing device. In this way, conventional machines can be brought to a higher standard of machine and process safety with relatively little effort - i.e. without it being necessary to completely replace the tools.

In an embodiment according to the invention, the counter bearing for the torque support, when it is designed in the form of a sleeve, is a profiled washer. This design leads to a compact construction of the device and also has the advantage that the corresponding component is relatively easy to manufacture.

In an embodiment according to the invention, the sensor for determining the torque is a strain gauge (SG) or a measuring method that works according to the physical principle of magnetostriction, such as a Pulsed Current Modulation Encoding (PCME) sensor.

A strain gauge provides an electrical chain variable that is proportional to the change in length of the strain gauge. In particular, the strain gauges are preferably arranged in the area of the torque arm so that their measuring range extends along the stress lines. This is preferably an extension direction that is essentially perpendicular to the axis of rotation of the shaft. One advantage of such an arrangement is that relatively large changes in length can be determined in this area, thus improving the measurement results. Of course, this can also be deviated from to a certain extent in order to be able to take application-specific requirements such as the robustness of the system during operation into account when positioning the strain gauges. In addition, it can be advantageous to arrange the strain gauges in the area of relatively thin sections of the torque arm and, if necessary, to use a large number of opposing strain gauges (outside and inside) on the appropriately designed torque arm.

A PCMC sensor is a sensor that uses the so-called inverse magnetostrictive effect. A magnetic field changes when a force acts on a magnetically coded component. Such sensors are known in the prior art. In a device according to the invention, the torsion (as a function of the reaction torque) can be measured directly on the shaft using such a sensor.

In an embodiment according to the invention, the signal processing device determines the reaction torque on the torque support and/or the shaft by means of the sensor and thus controls the drive of the shaft.

The signal processing device can receive the measured variables from one or more sensors. The sensors can be of the same type or use different measuring principles. Depending on the functional principle and the design of the sensors, several sensors can be used to record the reaction torque, preferably at several different points on the device. This has the advantage that redundant measurement of the torque is possible. This can, for example, achieve greater measurement precision or detect inconsistencies in the measurement - caused, for example, by the failure of a sensor or the breakage of a part of the device according to the invention. This leads to a further increase in the safety of the systems.

In an embodiment according to the invention, in addition to the sensor for determining the torque, at least one further sensor is provided for determining a rotation angle of the shaft. This is preferably selected from a group of sensors which includes optical, inductive or resistive sensors, in particular axial rotation angle sensors, Hall sensors, combinations thereof and the like.

The angle of rotation is measured against a (in principle arbitrary) fixed point next to the shaft. The zero position is determined during initialization.

Such an additional direct sensor leads to a further increase in the precision of the screwing process. In addition, redundancy is increased, which further improves the safety of the device. For example, with a state-of-the-art power screwdriver, it is not detected if the tool pawl is not working correctly. A system with indirect measurement would output an angle value that is not transferred to the tool spindle if the system does not re-reference itself using other physical parameters, which can, however, be subject to errors. An independent idle sensor self-test, as required for an MFU, cannot therefore be carried out correctly by the screwing system itself, since the incorrect values are not detected if the tool pawl is manipulated or the tool ratchet system fails. This means that a ratchet system that is not working correctly is not detected in the tightening process and can therefore lead to screw connections being tightened incorrectly without being noticed.

This also meets the requirements for screw systems of safety category A according to VDI/VDE 2862 Sheet 2.

• • Erfassung einer Längenänderung in einem Bereich wenigstens der Spannungslinie, vorzugsweise im Bereich der maximalen Spannungslinien eines Reaktionselementes, insbesondere der Drehmomentenstütze oder der Welle, mittels des Sensors, wobei die Längenänderung der Spannungslinie eine Funktion des Reaktions-Drehmoments ist;
• • Bestimmen eines Drehmoments der Welle im Bereich der Werkzeugaufnahme mittels der Signalverarbeitungseinrichtung und vorgegebenen Parametern;
• • Steuern der Energiezufuhr, als Funktion des Drehmoments der Welle.

A method according to the invention for driving a shaft with a tool holder by means of hydraulic or pneumatic energy supply has the following steps:

• • Detecting a change in length in a region of at least the stress line, preferably in the region of the maximum stress lines of a reaction element, in particular the torque support or the shaft, by means of the sensor, wherein the change in length of the stress line is a function of the reaction torque;
• • Determining a torque of the shaft in the area of the tool holder by means of the signal processing device and specified parameters;
• • Controlling the energy supply as a function of the shaft torque.

The detected change in length in an area of at least one stress line can be measured at one point or at several points, with one type of sensor or with several types of sensors. If there was no damage, for example a break, between the shaft and the reaction element, the sensor(s) will receive correlated values. In the case of redundant sensors, differences in the detection can be used as an indicator of a fault - in the sensor or the machine - and the machine can be stopped, for example, before damage to the screw system occurs.

The signal processing device links the values recorded by the sensor or sensors with specified parameters, for example functions or tables, which reflect the dependence of the sensor values on a change in the reaction torque. After this linking and in conjunction with a control algorithm, the signal processing device determines the target torque of the shaft (action torque).

A machine operating according to a method according to the invention can further be configured for self-test functionality.

This target torque is used to control the energy supply of the pressure source via a suitable interface, preferably an industrial interface. An analog current interface, an analog voltage interface or fast bus systems such as a CAN bus or optical buses are ideal for this.

In a method according to the invention, the signal processing device is suitable for intermittent control of the energy supply.

With such a design, the method according to the invention is particularly suitable for ratchet operation or for ratchet systems. While methods according to the state of the art are usually designed in two stages or work accordingly slowly, this method enables faster, more precise and error-tolerant work.

In a method according to the invention, the signal processing device for intermittent control operates at frequencies of 0.1 to 15 pressure peaks or strokes per second, in particular up to 10 pressure peaks or strokes per second, whereby this can vary in particular depending on the tool type.

With a system according to the invention, several adjustment processes can be carried out and high performance with fast and precise load changes is thus possible. This significantly increases the screwing performance, which leads to higher overall performance, improved efficiency and lower machine downtime.

In a method according to the invention, the control device for controlling the energy supply has a PID controller, whereby P controllers or PI controllers are also used depending on the main requirements of the screw system.

This makes it possible to meet even the highest demands on control, which are caused by the weight of the components involved, by flow resistance of the hydraulic or pneumatic system and by elastic deformation of the reactive parts.

Use of a device according to one of the preceding claims as a power wrench, in particular as a hydraulic power wrench, preferably for transmitting forces of more than 1,000 Newton meters, particularly preferably between 1,000 and 20,000 Newton meters.

Power screwdrivers according to the present invention are used in particular in power plant construction, in the assembly of large systems and components, e.g. assembly and maintenance of large wind turbines. The tool holder preferably has a hexagon drive or square drive.

Further features of the invention will become apparent from the following detailed description of embodiments of the invention in conjunction with the drawings and the claims.

• 1: die Skizze eines erfindungsgemäßen Hydraulikwerkzeuges mit einem axial um die Welle abgestützten Reaktionsarm;
• 2: die Skizze eines erfindungsgemäßen Hydraulikwerkzeugs mit einer nicht axial zur Welle angeordneten Reaktionsarmvorrichtung;
• 3: die Skizze eines erfindungsgemäßen Hydraulikwerkzeuges mit einer Reaktionshülse;
• 4: die Skizze eines erfindungsgemäßen Hydraulikwerkzeuges mit einer Reaktionshülse mit Öffnungen zur Aktionswelle;
• 5: Schema eines Verfahrens zum Antrieb einer Welle mit Werkzeugaufnahme gemäß dem Stand der Technik;
• 6: Schema eines Verfahrens zum Antrieb einer Welle mit Werkzeugaufnahme in einer erfindungsgemäßen Ausführungsform mit Erfassung des Drehmoments;
• 7: Schema eines Verfahrens zum Antrieb einer Welle mit Werkzeugaufnahme in einer erfindungsgemäßen Ausführungsform mit Erfassung des Drehmoments und des Drehwinkels.

Showing:

• 1 : the sketch of a hydraulic tool according to the invention with a reaction arm supported axially around the shaft;
• 2 : the sketch of a hydraulic tool according to the invention with a reaction arm device not arranged axially to the shaft;
• 3 : the sketch of a hydraulic tool according to the invention with a reaction sleeve;
• 4 : the sketch of a hydraulic tool according to the invention with a reaction sleeve with openings to the action shaft;
• 5 : Scheme of a method for driving a shaft with tool holder according to the prior art;
• 6 : Diagram of a method for driving a shaft with tool holder in an embodiment according to the invention with detection of the torque;
• 7 : Diagram of a method for driving a shaft with tool holder in an embodiment according to the invention with detection of the torque and the angle of rotation.

1 shows the sketch of a power wrench according to the invention. This has a housing barrel, on the underside of which a shaft 12 with a tool holder is arranged. The shaft 12 is connected via the hydraulic coupling 2 to a pressure source (e.g. to a hydraulic unit; not shown) via an internal piston ratchet mechanism (not shown) for supplying hydraulic energy. Furthermore, a reaction arm 5 is arranged on the housing 1, which is supported axially around the shaft 12 and is connected in a rotationally fixed manner to a section of the housing 1. The reaction arm 5 is intended to absorb the reaction torque - as a counterpart to the action torque of the shaft 12. The reaction arm 5 experiences torsion and/or stretching under load, ie when the shaft 12 is actuated. Under load, stress lines therefore form in and on the reaction arm 5. A sensor 13 is arranged on the reaction arm 5, preferably in the area of the maximum stress lines. This sensor 13 - e.g. a strain gauge - detects a change in length during torsion and/or extension of the reaction arm 5, which is proportional to the reaction torque on the reaction arm 5. The sensor 13 is connected to a signal processing device 7. This determines the target torque of the shaft 12 in the area of the tool holder, based on the sensor 13 and specified parameters. The signal processing device 7 controls the pressure source with this target torque.

2 shows the sketch of an alternative embodiment of the power wrench 20 according to the invention with a reaction arm device not arranged axially to the shaft 12. Elements with the same reference numerals as in 1 the same elements.

The reaction arm 9 is arranged differently than in 1 ; nevertheless, when loaded - which is caused by an action torque of the shaft 12 - it also experiences a torsion and/or a stretching, which can be detected by means of one or more torque sensors. In the embodiment shown, three sensors are connected to the signal processing device 7: a torque sensor 10, which is arranged in the tool housing, a torque sensor (not visible) on the back of the reaction arm 9 and a sensor 8 for detecting the angle of rotation, which is arranged on the upper part of the housing 1.

3 shows the sketch of a power wrench 20 according to the invention with a reaction sleeve 3 as a torque support. The internal shaft 11 is arranged inside the reaction sleeve 3 (only partially visible). A torque sensor 13 - e.g. DMS - is arranged on the outside of the reaction sleeve 3, which detects changes in length due to the reaction torque of the reaction sleeve 3. A further sensor system 4 is arranged on the reaction sleeve 3, which is designed here as a PCMC sensor. This PCMC sensor 4 directly measures the reaction torque on the shaft 11, using the so-called inverse magnetostrictive effect. A magnetic field changes when a force acts on a magnetically coded component.

4 shows the sketch of another, alternatively designed power wrench according to the invention. This is constructed similarly to 3 shown. However, here the torque sensor 13 is arranged in openings of the reaction sleeve 3 towards the action shaft 11.

Tests show that in this embodiment the easily determinable lines of force are located in the lower or upper area of the openings, i.e. off-center. In particular, the arrangement must avoid arranging the strain gauge in the area of so-called neutral lines, since no or only slight changes in length can be determined there.

5 shows a diagram of a method for driving a shaft 12 with a tool holder according to the prior art, using indirect measurement. The energy supply to the shaft 12 takes place via the hydraulic coupling 2. The shaft 12 exerts an action torque on the tool or the tool holder. The signal processing device 7 measures the hydraulic (or pneumatic) pressure of the energy supply, which is generated by a hydraulic pump, for example, via a sensor between the pressure source and the hydraulic coupling 2, and thus controls the pressure source. This measured pressure is used to calculate the target torque value on the shaft 12.

6 shows a diagram of a method for driving a shaft 12 with a tool holder in an embodiment according to the invention. As in 5 the energy supply to the shaft 12 is via the hydraulic coupling 2, and the shaft 12 exerts an action torque on the tool or the tool holder. However, by means of direct measurement by one or more torque sensors 4, 10, 13, the reaction torque is measured at a torque support 3, 5, 9 and transmitted to the signal processing device 7. This controls the pressure source, here on the basis of the reaction torque.

7 shows a diagram of a method for driving a shaft 12 with a tool holder in a further embodiment according to the invention. The detection of the reaction torque takes place as in 6 by means of direct measurement by one or more torque sensors 4, 10, 13. In addition, the angle of rotation of the shaft is recorded by means of the angle of rotation sensor 8. Here, the pressure source is controlled based on the reaction torque and the angle of rotation.

List of reference symbols:

1

Housing

2

Hydraulic coupling

3

Reaction sleeve

4

Sensor system on reaction sleeve (PCMC sensor)

5

Reaction arm, axial to the action shaft

7

Signal processing device

8th

Angle sensor

9

Low reaction, not axial to the action shaft

10

Torque sensor in the tool housing

11

Internal action shaft

12

Action shaft, shaft with tool holder

13

Torque sensor (e.g. strain gauge)

20

Power screwdriver

Claims (12)

Torque support (3, 5, 9) of a device (20) for pneumatically or hydraulically driving a shaft (11, 12) comprising a tool holder and a housing (1), wherein the torque support (3, 5, 9) can be connected in a rotationally fixed manner to at least one section of the housing for receiving a reaction torque and has at least one sensor (4, 10, 13) for determining a reaction torque, which is connected to a signal processing device (7), wherein at least the torque support (3, 5, 9) and/or the shaft that can be received in the torque support forms a reaction element which forms at least one stress line during operation of the device (20), characterized in that the sensor (4, 10, 13) detects at least one change in length in a region of the at least one stress line, preferably in the region of the maximum stress lines of the reaction element (3, 5, 9) during operation of the device (20) and by means of the signal processing device (7) and predetermined parameters an action torque of the shaft (11, 12) in the area of the tool holder is determined. Device (20) for pneumatically or hydraulically driving a shaft (11, 12) comprising a tool holder, a housing (1), a torque support (3, 5, 9) which is connected to at least one section of the housing for receiving a reaction torque and at least one sensor (4, 10, 13) for determining a reaction torque, which is connected to a signal processing device (7), wherein at least the torque support (3, 5, 9) and/or the shaft (11, 12) form a reaction element which has at least one stress line during operation, characterized in that the sensor (4, 10, 13) detects at least one change in length in a region of the at least one stress line, preferably in the region of the maximum stress lines of the torque support (3, 5, 9) and/or shaft (11, 12), during operation of the device (20) and, by means of the signal processing device (7) and predetermined parameters, an action torque of the shaft (11, 12) in the region the tool holder. Device according to Claim 1 or 2 , characterized in that the torque support is a support foot (5) or reaction arm (9) extending around the shaft or in particular a sleeve (3), which are connected in a rotationally fixed manner to the housing of the shaft or a drive shaft (11, 12) and interact with a further counter bearing in the region of a screw connection. Device according to Claim 2 , characterized in that the counter bearing for the torque support in the form of a sleeve is a profiled washer. Device according to one of the preceding claims, characterized in that the sensor (4, 10, 13) for determining the torque is a strain gauge or a magnetostriction sensor, in particular a PCMC sensor. Device according to one of the preceding claims, characterized in that the signal processing device (7) measures the reaction torque on the torque support (3, 5, 9) and/or the shaft (11, 12) by means of the sensor (4, 10, 13) and thus controls the drive of the shaft (11, 12). Device according to one of the preceding claims, characterized in that in addition to the sensor (4, 10, 13) for determining the torque, at least one further sensor (8) is provided for determining an angle of rotation of the shaft (11, 12) and this is preferably selected from the group of sensors which comprises optical, inductive or resistive sensors, in particular axial angle of rotation sensors, Hall sensors, combinations thereof and the like. Procedure according to Claim 1 or 2 for driving a shaft (11, 12) with a tool holder by means of a hydraulic or pneumatic energy supply (2), with the steps: - detecting a change in length in a region of at least the stress line, preferably in the region of the maximum stress lines of the torque support (5, 9) by means of the sensor (4, 10, 13), the change in length of the stress line being a function of the reaction torque, - determining a torque of the shaft (11, 12) in the region of the tool holder by means of the signal processing device (7) and predetermined parameters, - controlling the energy supply (2) as a function of the torque of the shaft (11, 12). Procedure according to Claim 8 , characterized in that the signal processing device (7) is suitable for intermittent control of the energy supply. Procedure according to Claim 9 , characterized in that the signal processing device (7) for intermittent control operates at frequencies of 0.1 to 15 pressure peaks or strokes per second, in particular up to 10 pressure peaks or strokes per second. Method according to one of the Claims 8 until 10 , characterized in that the control device (7) for controlling the energy supply (2) has at least one P-controller, PI-controller or PID-controller. Use of a device (20) according to one of the preceding claims as a power wrench, in particular as a hydraulic power wrench, preferably for transmitting forces of more than 1,000 Newton meters, particularly preferably between 5,000 and 20,000 Newton meters.

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