MEDICAL OR DENTAL TREATMENT DEVICE AND TOOL FOR SUCH A TREATMENT DEVICE

Abstract

A medical or dental treatment device comprises a tool retainer, a measuring coil and an evaluation device. The tool retainer can be connected to a plurality of different tools. The measuring coil can be supplied with a periodic electrical energy. The evaluation device can be connected to the measuring coil for detecting whether a tool is connected to the treatment device or which of a plurality of tools is connected to the treatment device. On the basis of an electromagnetic (e.g., inductive) coupling between the tool accommodated in the tool retainer and the measuring coil supplied with the periodic energy, a periodic measurement signal specific to each tool can be generated and assigned by the evaluation device to the tool. The evaluation device determines the phase shift of the electrical voltage and of the electric current of the periodic measurement signal.

Claims

1. A medical or dental treatment device, which can be connected to a plurality of different tools, wherein the medical or dental treatment device comprises: a tool retainer for connecting the treatment device to a tool, at least one measuring coil which is connected to an electrical energy supply device via an electrical line and which can be supplied with a periodic electrical energy supply from the electrical energy supply device, and an evaluation device electrically connected to the at least one measuring coil for detecting whether a tool is connected to the treatment device or which of a plurality of tools is connected to the treatment device, wherein due to an inductive coupling between the tool accommodated in the tool retainer and the at least one measuring coil supplied with the periodic electrical energy, a periodic measurement signal specific to the tool is generated and assigned by the evaluation device to the tool, and wherein the evaluation device determines the phase shift of the electrical voltage and of the electric current of the periodic measurement signal.

2. The medical or dental treatment device according to claim 1, wherein the evaluation device further determines the amplitude of the electrical voltage of the periodic measurement signal.

3. A medical or dental treatment device according to claim 1, further comprising at least one tool which can be connected to the treatment device, wherein the at least one tool comprises a tool shaft and a working end connected to the tool shaft for working on a treatment site, wherein the tool shaft comprises at least one electrically conductive identification element in which, through the inductive coupling between the tool accommodated in the tool retainer and the at least one measuring coil supplied with the periodic energy, an alternating electric current and/or electrical eddy currents can be induced, which feeds back onto the periodic electrical energy flowing in the at least one measuring coil in order to generate the periodic measurement signal which can be assigned to the respective tool.

4. The medical or dental treatment device according to claim 3, wherein the at least one electrically conductive identification element is provided on a base material of the tool shaft, wherein the at least one electrically conductive identification element and the base material comprise different materials.

5. The medical or dental treatment device according to claim 3, wherein the at least one electrically conductive identification element comprises at least one of a wire, a winding, a coil, a coating, a film, a layer or a sleeve.

6. The medical or dental treatment device according to claim 3, wherein the at least one electrically conductive identification element forms a closed electrical circuit surrounding the tool shaft, in which the alternating electric current can flow.

7. The medical or dental treatment device according to claim 3, wherein the at least one electrically conductive identification element comprises two separated ends.

8. The medical or dental treatment device according to claim 1, comprising a plurality of different tools, each of the tools having a tool shaft with at least one electrically conductive identification element wherein, in order to detect or differentiate the tools by the evaluation device, the electrically conductive identification elements of the tools differ in at least one of the following parameters: the axial lengths of the electrically conductive identification element with respect to a longitudinal axis of the tool shaft; the cross-sectional areas of the electrically conductive identification elements; the thicknesses of the electrically conductive identification elements transversely to or radially to a longitudinal axis of the tool shaft; the thicknesses of the layers of the electrically conductive identification elements deposited on the tool shaft; the materials of the electrically conductive identification elements; the number of turns and/or the lengths of the electrically conductive identification elements configured as coils or windings; or the wire diameter of the electrically conductive identification elements configured as coils or windings.

9. The medical or dental treatment device according to claim 8, wherein in order to detect or differentiate the plurality of different tools by the evaluation device, the plurality of tools further differ in at least one of the following parameters: the base material of the tool shaft; the diameter of at least one section of the tool shaft; or the length of the tool shaft.

10. The medical or dental treatment device according to claim 3, wherein the tool shaft of the at least one tool comprises at least two electrically conductive and separated identification elements.

11. The medical or dental treatment device according to claim 1, further comprising a plurality of measuring coils which are electrically connected to the evaluation device for detecting whether a tool is connected to the treatment device or which of a plurality of tools is connected to the treatment device.

12. The medical or dental treatment device according to claim 1, further comprising an electrical energy supply device which is configured to provide the at least one measuring coil with periodic electrical energy at different frequencies so that, in order to detect whether a tool is connected to the treatment device or which of a plurality of tools is connected to the treatment device, the at least one measuring coil can be supplied with periodic electrical energy at different frequencies.

13. The medical or dental treatment device according to claim 1, wherein the periodic electrical energy supply is a sinusoidal electrical energy supply.

14. A method for detecting whether a tool is connected to a treatment device or which of a plurality of tools is connected to said treatment device, comprising: supplying at least one measuring coil with periodic electrical energy, establishing an inductive coupling between a tool accommodated in a tool retainer and the at least one measuring coil supplied with the periodic energy, generating a periodic measurement signal which is specific to each tool and which can be assigned to the respective tool by an evaluation device, and detecting whether a tool is connected to the treatment device or which of a plurality of tools is connected to the treatment device with the evaluation device, wherein the evaluation device determines the phase shift of the electrical voltage and of the electric current of the periodic measurement signal.

15. The method of claim 14, further comprising determining the amplitude of the electrical voltage of the periodic measurement signal with the evaluation device to detect whether a tool is connected to the treatment device or which of a plurality of tools is connected to the treatment device.

16. The method of claim 14, wherein an alternating electric current and/or electrical eddy currents is/are induced in at least one electrically conductive identification element of the at least one tool due to the inductive coupling between said tool accommodated in the tool retainer and the at least one measuring coil supplied with the periodic energy, wherein said alternating electric current and/or electrical eddy currents feeds back onto the periodic electrical energy flowing in the at least one measuring coil in order to generate the periodic measurement signal which can be assigned to the respective tool.

17. The method of claim 14, wherein generating a periodic measurement signal comprises generating a sinusoidal measurement signal.

18. A medical or dental tool, comprising a tool shaft, and a working end connected to the tool shaft for working on a treatment site, wherein the tool shaft comprises at least one electrically conductive identification element in which due to an inductive coupling between said tool and a measuring coil supplied with periodic electrical energy, an alternating electric current and/or electrical eddy currents can be induced, which feeds back onto the periodic electrical energy flowing in the at least one measuring coil in order to generate a periodic measurement signal which can be assigned to the tool.

19. A medical or dental treatment device having at least one tool according to claim 18.

20. The medical of dental tool of claim 18, wherein the measuring coil is supplied with sinusoidal electrical energy.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0072] FIG. 1 shows an embodiment of a medical or dental treatment device with an evaluation device for detecting whether a tool is connected to the treatment device or which of a plurality of tools is connected to the treatment device, and a handle element for tartar removal;

[0073] FIG. 2 shows a sectional view of the tool side end of the handle element for tartar removal of FIG. 1;

[0074] FIG. 3 shows a schematic view of an embodiment of a circuit diagram of a medical or dental treatment device with an evaluation device for detecting whether a tool or which of a plurality of tools is connected to the treatment device;

[0075] FIG. 4 shows a further schematic view of an embodiment of a circuit diagram for a medical or dental treatment device with an evaluation device for detecting whether a tool or which of a plurality of tools is connected to the treatment device;

[0076] FIG. 5 shows a schematic view of a further embodiment of a circuit diagram for a medical or dental treatment device with an evaluation device for detecting whether a tool or which of a plurality of tools is connected to the treatment device;

[0077] FIG. 6 shows a plurality of tools or a set of tools with a plurality of tools each with an electrically conductive identification element in the form of at least one winding;

[0078] FIG. 7 shows a plurality of tools or a set of tools with a plurality of tools each with an electrically conductive identification element in the form of at least one coil;

[0079] FIG. 8 shows a plurality of tools or a set of tools with a plurality of tools each with an electrically conductive identification element in the form of at least one film;

[0080] FIG. 9 shows a plurality of tools or a set of tools with a plurality of tools each with an electrically conductive identification element in the form of at least one coating;

[0081] FIG. 10 shows a plurality of tools or a set of tools with a plurality of tools each with an electrically conductive identification element in the form of at least one split sleeve;

[0082] FIG. 11 show a tool with two separated electrically conductive identification elements in the form of a coil and a split sleeve;

[0083] FIG. 12 shows a cross-section through the tool shafts of a plurality of tools, in particular a set of tools, each with an electrically conductive identification element in the form of at least one coating with different layer thicknesses;

[0084] FIG. 13 shows two schematic diagrams with the respective phase shifts and the different amplitudes of two different tools in order to differentiate the tools by the evaluation device.

DETAILED DESCRIPTION

[0085] The medical or dental treatment device 1 shown in FIG. 1 is configured as a tartar removal device or a scaling device. It comprises a handle element or handpiece 18, a control device or a control unit 20 and a supply or connection tube 19 connecting the control unit 20 and the handpiece 18.

[0086] The preferably straight elongate handpiece 18 shown in FIG. 2 has a hollow cylindrical outer sleeve 21 in which, as will be described below in detail, the following are disposed, inter alia: the drive unit 2 for tools 3 which can be connected to the handpiece 18, at least parts of the evaluation device 4 for detecting whether a tool is connected to the treatment device or which of a plurality of tools is connected to the treatment device (see FIG. 3, also termed the tool detecting device 4 below), a tool receiving device or tool retainer 22 for detachably accommodating a plurality of different tools 3, and an illumination device 9 which preferably encircles the tool retainer 22. The control device or control unit 20 has a housing 23 with a display 24 for displaying fixed or adjustable operational parameters or the tool 3 detected by the tool detecting device 4, one or more actuators 25, such as pushbuttons, for selecting or changing operational parameters, a handpiece rest 26 and a source of liquid 27 with a cooling or rinsing liquid.

[0087] The power or connecting tubing 19 comprises a plurality of media lines or lines for resources, in particular electrical lines which connect the drive unit 2 and the tool detecting device 4 to an electrical energy supply device 12 (see FIG. 3). A media line 30 connects the liquid source 27 to the tool retainer 22 and a tool 3 accommodated therein, so that liquid can be dispensed via a liquid dispensing opening 28 of the tool 3 onto the treatment side and/or the tool 3, in particular its working end 3A.

[0088] As can be seen in FIG. 2, the drive unit 2 comprises a vibration generator 8 which is preferably a piezoelectric vibration generator with a plurality of piezoelectric elements. The vibration generator 8 is connected to the tool 3 in order to transmit vibrations via a sonotrode 29, which in particular is designed as a hollow vibrating shaft. At one end of the sonotrode 29, the tool retainer 22 is designed for detachable accommodation of a plurality of tools 3. The tool retainer 22 comprises an internal thread, for example, which can be connected to an external thread of the tool 3, which in particular is provided on its tool shaft 3B. The tool retainer 22 may additionally or alternatively have a conical friction surface, which forms a frictional connection with a second conical friction surface of the tool 3, which in particular is provided on its tool shaft 3B.

[0089] The media line 30 connected to the liquid source 27 opens into the hollow sonotrode 29, from which the cooling liquid is transferred into a channel 31 of the tool 3 in order to discharge through the liquid dispensing opening 28.

[0090] The sonotrode 29, the tool retainer 22 and a tool shaft 3B of a tool accommodated therein are surrounded by the illumination device 9 at the tool side end of the handpiece 18.

[0091] Furthermore, at least one preferably cylindrical measuring coil 5, 5A is provided at the tool side end of the handpiece 18 and forms part of the tool detecting device 4 (see also FIGS. 3-5). The at least one measuring coil 5, 5A in particular surrounds at least one section of the tool retainer 22 or is disposed adjacent to the tool retainer 22. The at least one measuring coil 5, 5A is preferably disposed in the handpiece 18 such that when a tool 3 is accommodated in the tool retainer 22, an electrically conductive identification element 6 of the tool 3 is positioned close to the at least one measuring coil 5, 5A, in particular within the at least one measuring coil 5, 5A so that, because of an electromagnetic in particular inductive coupling between the tool 3 accommodated in the tool retainer 22, in particular its at least one electrically conductive identification element 6, and the at least one measuring coil 5, 5A supplied with periodic, in particular sinusoidal electrical energy (alternating current) from the electrical energy supply device 12, a periodic, in particular sinusoidal measurement signal can be generated which is specific for each of the plurality of tools 3 and which can be assigned to the respective tool 3 by the evaluation device 4.

[0092] The at least one measuring coil 5, 5A is, for example, supported on a support sleeve 32 formed from plastic. Preferably, a magnetic feedback element 33, which in particular consists of sheet metal, surrounds the at least one measuring coil 5, 5A, in particular on its outside and preferably also at least partially on its inside facing the tool shaft 3B and the sonotrode 29. This sleeve-like feedback element 33, which is provided with an opening to the inside, produces a concentration or compaction of the magnetic field lines or an increase in the magnetic flux density, in particular in the at least one electrically conductive identification element 6 of the tool shaft 3B of the tool 3 accommodated in the tool retainer 22, so that detection of the tool 3 by the tool detecting device 4 is facilitated. The magnetic feedback element 33 in particular also supports the detectability of a plurality of electrically conductive identification elements 6.

[0093] Preferably, the at least one measuring coil 5, 5A, in particular also the feedback element 33, is encapsulated by an encapsulation material, for example a resin, in particular epoxy resin, in order to protect it from external influences and contamination and to ensure stability of form.

[0094] The illumination device 9, which can include a circuit board 35 and one or more optical semiconductor elements 10, in particular light-emitting diodes, is disposed distally adjacent to the at least one measuring coil 5, 5A. The circuit board 35 is annular in shape, so that a tool 3 inserted into the tool retainer 22 can protrude through its central opening. A transparent plastic sleeve 36 covers the circuit board 35 and the light-emitting diodes 10 and protects them from contamination and mechanical stresses.

[0095] The electrical supply in the handpiece 18 for supplying the at least one measuring coil 5, 5A with electric current from the electrical energy supply device 12, preferably also the illumination device 9, is via an electrical line 11. The electrical line 11 is connected with the electrical energy supply device 12 via an electrical line in the supply or connection tube 19.

[0096] The medical or dental treatment device 1 shown in the form of a schematic circuit diagram in FIG. 4 comprises an evaluation device 4 for detecting whether a tool or which of a plurality of tools is connected to the treatment device, with a (single) measuring coil 5 and a (single) electrically conductive identification element 6 on the tool shaft 3B of the tool 3. The measuring coil 5 is connected to the electrical energy supply device 12 and the other components of the evaluation device 4 via an electrical line 11.

[0097] The medical or dental treatment device 1 shown in the form of a schematic circuit diagram in FIG. 5 comprises an evaluation device 4 for detecting whether a tool or which of a plurality of tools is connected to the treatment device, with two measuring coils 5, 5A and two mutually separated electrically conductive identification elements 6 on the tool shaft 3B of the tool 3. Preferably, the two electrically conductive identification elements 6 respectively are configured as independent electrical circuits 37. The measuring coils 5 are connected together, to the electrical energy supply device 12 and to the other components of the evaluation device 4 via an electrical line 11.

[0098] Preferably, an illumination device 9 is also connected to the electrical energy supply device 12 via the electrical line 11 to supply electricity to the optical semiconductor element 10. Preferably, the electrical line 11 can be connected or is connected to an electrical energy supply device 12 in order to supply direct current to the illumination device 9 and to supply the coil of the tool detecting device 4 with alternating current. In order for the electrical line 11 to be able to supply the illumination device 9 with direct current and the at least one measuring coil 5 with alternating current, the alternating current is modulated to direct current or the two voltages are superimposed on each other. Alternatively, it is also possible to supply the illumination device 9 with alternating current from the electrical energy supply device 12 via the electrical line 11.

[0099] Preferably, the illumination device 9, in particular at least one optical semiconductor element 10, is disposed on a support 49, for example the circuit board 35. Particularly preferably, the support 49 is also a part of the tool detecting or evaluation device 4 and is, for example, connected to the coil ends of the at least one measuring coil 5 or carries at least one element of the evaluation device 4.

[0100] FIG. 3 shows, in the form of a schematic circuit diagram, the construction of the tool detecting device 4, in particular of FIG. 5, in more detail.

[0101] The evaluation device 4 for detecting whether a tool or which of a plurality of tools is connected to the treatment device 1 comprises a microcontroller unit 40 which, for example, is disposed in the control device or the control unit 20 or forms at least a part of the control device or the control unit 20. The microcontroller unit 40 comprises a microcontroller 41, the electrical energy supply device 12 to supply the at least one measuring coil 5, preferably also the illumination device 9 with electricity, a device for measuring the voltage 42 and a device for measuring the current 43, preferably indirectly via a voltage measurement. These elements 12, 42, 43 mentioned are preferably configured as a part of the microcontroller 41 and/or are controlled via the microcontroller 41 by software.

[0102] The device for measuring voltage 42 and the device for measuring current 43 are in particular provided such that the electrical voltage and the electric current (value) of the periodic, in particular sinusoidal measurement signal received from the at least one measuring coil 5 can be determined, from which the phase shift for detecting whether a tool or which of a plurality of tools is connected to the treatment device 1 can be determined. Preferably, the device for measuring voltage 42 is also intended, for the purposes of tool detection, to determine the amplitude, in particular the extreme values of the amplitude, of the electrical voltage of the periodic, in particular sinusoidal measurement signal.

[0103] Preferably, between the at least one measuring coil 5 and the electrical energy supply device 12 are further electrical or electronic components, for example a filter 44 for filtering or smoothing (the high frequency transients caused by the microcontroller of the electrical energy supply device 12 of) the periodic, in particular sinusoidal electrical energy provided by the electrical energy supply device 12 and/or an amplifier 45 to amplify the periodic electrical energy (of the alternating current).

[0104] A device for adjusting the level of the voltage and/or a filter 46 protect the microcontroller unit 40 and its components from voltages of the periodic, in particular sinusoidal measurement signal transmitted by the at least one measuring coil 5 which are too high. A current-voltage transformer 47 determines the value of the voltage of the periodic, in particular sinusoidal measurement signal from the measured value of the current of the periodic, in particular sinusoidal measurement signal.

[0105] Since the treatment device 1 of FIG. 3 has two measuring coils 5, 5A, but only one evaluation device 4 or microcontroller unit 40, it is necessary, in order to detect the tool, to supply the two measuring coils 5, 5A sequentially with periodic, in particular sinusoidal electrical energy (alternating current). To this end, a switching device 48 is provided which is electrically connected to the respective two coil ends of the two measuring coils 5, 5A, and is configured to supply the two measuring coils 5, 5A sequentially with the periodic, in particular sinusoidal electrical energy from the electrical energy supply device 12 and in particular also to connect to the microcontroller unit 40, the microcontroller 41, the voltage measurement device 42 and/or the current measurement device 43. The switching device 48 is preferably disposed on the support 49 (see also FIG. 5).

[0106] The switching device 48 is clearly an optional element which, for example, is not necessary when the treatment device 1 has only one measuring coil 5 (see FIG. 4) or when the treatment device 1 has a plurality of measuring coils 5, 5A and comprises for each coil of the plurality of measuring coils 5, 5A at least one independent device for measuring voltage 42 and one independent device for measuring current 43 or an independent microcontroller unit 40.

[0107] FIGS. 6 to 12 show various tools 3 which in particular are provided for use with a treatment device 1. Two or more or all of the tools shown may form a set of tools. Each of the depicted tools has at least one electrically conductive identification element 6 so that it can be identified by the evaluation device 4 for detecting whether a tool is connected to the treatment device 1 or which of a plurality of tools is connected to the treatment device 1. The electrically conductive identification element 6 is a separate element provided on a base material 7 of each tool on the tool shaft 3B.

[0108] In the tools of FIG. 6, the electrically conductive identification element 6 is respectively configured as a winding 13. The windings 13 in particular respectively comprise only a single turn. The windings 13 in particular are each configured as a closed electrical circuit 37 (see also FIG. 12), in which an alternating current flowing about the tool shaft 3B and/or the longitudinal axis 38 of the tool shaft 3B can be induced. The windings 13 of the three different tools of FIG. 6 differ in particular in their axial lengths (with respect to the longitudinal axis 38), so that they produce different phase shifts and/or amplitudes of the periodic, in particular sinusoidal measurement signal and thus can be distinguished by the evaluation device 4. Because of the large axial extent of the single turn of the winding 13, at least some of the windings 13 of the various tools 3 form sleeves or sleeve-like elements. Clearly, the windings 13 may also differ in further properties, in particular those mentioned above, for example in their material, their thickness and/or their radial extent (with respect to the longitudinal axis 38).

[0109] In the tools of FIG. 7, the electrically conductive identification element 6 is respectively configured as a coil 14. The coil 14 may, for example, have an insulated winding wire or a flexible printed circuit board. In particular, the coils 14 comprise a plurality of turns. The coils 14 are in particular respectively configured as a closed electrical circuit 37, in which an alternating current flowing about the tool shaft 3B and/or the longitudinal axis 38 of the tool shaft 3B can be induced. The coils 14 of the three different tools of FIG. 7 differ in particular in their axial lengths (with respect to the longitudinal axis 38) and/or in the number of turns and also in the number of coils 14. While the first two tools 3 each have only one coil 14, the third tool 3 has two axially separated coils 14 for detection through the evaluation device 4. Clearly, the coils 14 may also differ from each other in other properties, in particular those mentioned above, for example in their material and/or their cross-sectional areas.

[0110] In the tools of FIG. 8, the electrically conductive identification element 6 is respectively formed as a film 17, wherein respectively, two separated films 17 are disposed on one tool shaft 3B. In particular, the films are each configured as a closed electrical circuit 37, in which an alternating current flowing around the tool shaft 3B and/or the longitudinal axis 38 of the tool shaft 3B can be induced. The films 17 of the various tools of FIG. 8 differ in particular in their axial lengths (with respect to the longitudinal axis 38), so that they produce different phase shifts and/or amplitudes of the periodic, in particular sinusoidal measurement signal and thus can be distinguished by the evaluation device 4. Because of the large axial extent of the films 17, at least some of these films 17 of the various tools form sleeves or sleeve-like elements. Clearly, the films 17 may also differ from each other in other properties, in particular those mentioned above, for example in their material, in their thickness and/or in their radial extent (with respect to the longitudinal axis 38).

[0111] In the tools of FIG. 9, the electrically conductive identification element 6 is respectively configured as a coating 15, wherein respectively three axially separated coatings are disposed on one tool shaft 3B. The coatings 15 are in particular respectively configured as a closed electrical circuit 37 in which an alternating current flowing around the tool shaft 3B and/or the longitudinal axis 38 of the tool shaft 3B can be induced. The coatings 15 of the various tools of FIG. 9 again differ in particular in their axial lengths (with respect to the longitudinal axis 38), so that they produce different phase shifts and/or amplitudes of the periodic, in particular sinusoidal measurement signal and thus can be distinguished by the evaluation device 4. Clearly, the coatings 15 may also differ from each other in other properties, in particular those mentioned above, for example in their material and/or layer thickness.

[0112] In the tools of FIG. 10, the electrically conductive identification element 6 is respectively configured as a sleeve 16, which in particular is split. The split sleeves 16 have two electrically separated ends 39A, 39B which in particular are formed by the gap or slit 50 formed between the two ends 39A, 39B. The split sleeves 16 thus do not form a closed electrical circuit, so that only eddy currents can be induced in the split sleeves 16. The sleeves 16 of the various tools of FIG. 10 again differ in particular in their axial lengths (with respect to the longitudinal axis 38), so that they produce different phase shifts and/or amplitudes of the periodic, in particular sinusoidal measurement signal and thus can be distinguished by the evaluation device 4. Clearly, the coatings 15 may also differ from each other in other properties, in particular those mentioned above, for example in their material, their thickness and/or their radial extent (with respect to the longitudinal axis 38).

[0113] The tool of FIG. 11 comprises two different electrically conductive identification elements 6, for example a coil 14 and a split sleeve 16 are shown. Obviously, other electrically conductive identification elements 6 mentioned above may be combined on a tool 3, wherein every possible combination of two or more of the electrically conductive identification elements 6 mentioned above may be envisaged.

[0114] Due to the cross-section through the tool shaft 3B of the tools 3 shown in FIG. 12, it is particularly easy to see that the electrically conductive identification elements 6 differ in their thickness, layer thickness and/or radial extent (with respect to the longitudinal axis 38), so that they produce different phase shifts and/or amplitudes of the periodic, in particular sinusoidal measurement signal and thus can be distinguished by the evaluation device 4. Furthermore, it should be noted that the electrically conductive identification elements 6 are configured as a closed electrical circuit 37, in which an alternating current which flows around the tool shaft 3B and/or the longitudinal axis 38 of the tool shaft 3B can be induced. Clearly, the electrically conductive identification elements 6 may also differ in other properties, in particular those mentioned above, for example in their material and/or in their axial extent (with respect to the longitudinal axis 38).

[0115] FIG. 13 shows two schematic diagrams each with the phase shifts and the different amplitudes of two different tools 3 for identification of the tools by the evaluation device 4. As described in detail above, the phase shifts and the different amplitudes are in particular produced by the electrically conductive identification element 6 which is specific to each tool 3, preferably additionally by the base material of the tool 3. The phase shift can clearly be seen in both diagrams. The current signal, shown as a dashed line, follows the voltage signal, shown as a solid line, with a temporal shift. The periodic, in particular sinusoidal measurement signals of the two diagrams, i.e., of the two tools detected by the evaluation device 4, differ in their phase shifts and in their amplitudes, in particular the extreme values of the amplitudes or amplitude heights.

[0116] The embodiments described or shown in particular serve to illustrate the invention. The features disclosed in one embodiment are therefore not limited to that embodiment, but may be combined individually or together with one or more features of another embodiment.