JPWO2019020165A5 - - Google Patents

Description

The invention consists of a rotatable tool in the form of a saw blade or a milling cutter, a sensor device for detecting a mechanical quantity dependent on the force emanating from the tool, and an information-communicating connection with the sensor device. With respect to power tools having a control device, the control device is designed to recognize the phenomenon of the power tool according to the detected mechanical quantity.

US Pat. No. 6,300,000 describes a table saw with a kickback detection system, which comprises a sensor, which is configured to detect the axis excursion as a scalar quantity. there is The controller compares this detected excursion to a scalar threshold to see if kickback is present.

International Application Publication No. 2014/105935

SUMMARY OF THE INVENTION It is an object of the present invention to modify the power tool described at the outset in such a way that the recognition performed by the control device is improved.

This task is solved by a power tool according to claim 1 .
According to the invention, a sensor device is used for detecting mechanical vector quantities that depend on the force emanating from the tool. The mechanical vector quantities are illustratively forces, accelerations, velocities, deflections, deformations and/or mechanical stresses. The control device is configured to recognize the phenomenon and/or state of the power tool according to the direction and/or change in direction of the mechanical vector quantity detected by the sensor device.

According to the invention, therewith a vector quantity is detected and the phenomenon and/or state of the power tool is recognized on the basis of the direction and/or direction change of this vector quantity. This approach requires that the tool, in a given phenomenon and/or state of the power tool, thrust in a given direction and, for this reason, the direction and/or direction of the mechanical vector quantity that depends on the force emanating from the tool. It is based on the recognition that change is a good indicator for recognition of this phenomenon and/or condition.
Due to the consideration according to the invention of the direction and/or direction change of mechanical vector quantities, in particular an earlier phenomenon recognition and/or state recognition can take place than if the recognition were based solely on scalar quantities. This usually consists in that, first of all, a given direction exists and/or a given direction change occurs before a given scalar threshold is exceeded.
With a power tool according to the invention, a particularly early—and thus improved—recognition of phenomena and/or situations can thus be achieved.

The detected mechanical vector quantities illustratively simulate forces, accelerations, velocities, deflections, deformations and/or mechanical stresses and are preferably two-dimensional. This mechanical vector quantity depends on the force emanating from the tool. In particular, the direction of the detected vector quantity coincides with (corresponds to) the direction of the force emanating from the tool or, in particular, the direction of thrust of the tool relative to other components of the power tool. Expediently, the vector quantity is detected in the transmission path of the forces emanating from the tool.

A condition to be identified by the control device is in particular a so-called "kickback" of the power tool. With this concept "kickback" is understood a phenomenon in which, typically during the machining of a work material by a power tool, sudden and unexpected forces are exerted on the power tool and the work material. and this force causes the power tool or the work piece to be accelerated in that case and put into motion.
In table circular saws, kickback usually induces an unexpected acceleration of the work material in the direction of the user. In hand circular saws, kickback can result in unpredictable movement of the tool. Kickback can cause injury to the user and thus represents a compromise in operational reliability.

Kickback occurs in particular during abrupt, excessively rapid entry of the tool into the workpiece, during reverse sawing, during clamping of the tool in the workpiece, due to certain material properties (e.g., inhomogeneous wood, stress) and/or with blunt tools. The kickback phenomenon can be recognized particularly well by the above-described phenomenon recognition on the basis of the direction and/or direction change of the detected mechanical vector quantity.
With the kickback or kickback-phenomenon to be recognized here, the kickback that is equally imminent here, i.e. the cause of the kickback, has already been given; / or the phenomenon that no significant acceleration of the work piece has yet occurred or no significant acceleration of the power tool and/or the work piece has occurred.
Before the power tool or work piece is put into motion or accelerated significantly by kickback, this kickback already causes the force vector emanating from the tool to change its direction, causing the incoming force vector to change direction. be forewarned. The tool, ie, just before kickback or at the beginning of kickback, thrusts in a different direction than in normal operation. This thrust in different directions can be detected by mechanical vector quantity detection, thereby inferring that a kickback-condition exists.

Furthermore, it is possible that the phenomenon to be recognized is the entry of the tool into the workpiece, forward sawing, backward sawing.

A condition to be recognized is, in particular, the wear condition of the power tool, preferably a tool embodied as a saw blade.

Advantageous further configurations are subject matter of the dependent claims.

The invention furthermore relates to a method for the recognition of phenomena and/or states of power tools having rotatable tools configured as saw blades or milling cutters.
The method comprises the steps of detection of mechanical vector quantities dependent on the force emanating from the tool, i.e. force, acceleration, velocity, deflection, deformation and/or mechanical stress; recognizing the phenomenon and/or state of the power tool according to the direction and/or direction change of the vector quantity.

Expediently, the method is implemented using the power tool described herein.

Further exemplary details, as well as exemplary embodiments, are described below with reference to the figures.

1 is a schematic diagram of a power tool according to a first embodiment; FIG. Fig. 2 is an illustrative graph of phenomenon and/or state recognition based on the direction or change of direction of mechanical vector quantities; FIG. 4 is a cross-sectional view of a power tool according to a second embodiment; FIG. 5 is a cross-sectional view of a power tool according to a third embodiment; FIG. 11 is a cross-sectional view of a power tool according to a fourth embodiment; FIG. 11 is a cross-sectional view of a power tool according to a fifth embodiment; FIG. 11 is a cross-sectional view of one driven shaft and two bearings of a power tool according to a fifth embodiment; FIG. 11 is a schematic diagram of a power tool according to a sixth embodiment; Figure 3 is a block diagram of a method;

FIG. 1 shows an electric tool 10 according to a first embodiment.

This power tool 10 comprises a rotatable tool 1 in the form of a saw blade or milling cutter, a sensor device 2 and a control device 4 .
This sensor device 2 is designed to detect a mechanical vector quantity 3 . Mechanical vector quantities 3 are forces, accelerations, velocities, deflections, deformations and/or mechanical stresses. Moreover, this mechanical vector quantity 3 depends on the force emanating from the tool 1 . The control device 4 is communicatively connected to the sensor device 2 and follows the direction and/or change in direction of the mechanical vector quantity 3 sensed by the sensor device 2 to the phenomenon and/or of the power tool 10 . It is made to recognize the state.

By performing phenomenon recognition and/or state recognition of the power tool 10 based on the direction and/or direction change of the detected mechanical vector quantity 3, the phenomenon change or state change of the power tool 10 is already It can be confirmed very early. This phenomenon recognition and/or situation recognition is improved accordingly.

Exemplary details of power tool 10, as well as further exemplary embodiments, are described below.

Power tool 10 is advantageously a saw, in particular a hand circular saw or a plunge saw. It is also possible for this power tool 10 to likewise be designed as a flat dowel milling machine. The tool 1 is in particular circular and rotates in the operating state exemplary clockwise.

By way of example, the power tool 10 comprises a housing 6 in which the sensor device 2 and the control device 4 are arranged. The housing 6 is provided with a rest surface 9 with which the power tool 10 can rest on a workpiece 11 to be machined.

The power tool 10 has a drive device 7 . This drive 7 comprises, for example, an electric motor and a transmission. This drive 7 is preferably controlled by the control device 4 .
The power tool 10 further comprises a driven shaft 8 , which can be driven by a drive 7 . The tool 1 is mechanically connected with the driven shaft 8 . Expediently, this tool 1 is fixed to the driven shaft 8 .

The power tool 10 also has a carrier structure 21 , which is expediently arranged in the housing 6 . The driven shaft 8 is, for example, mounted on this carrier structure 21 . Furthermore, it is possible for this carrier structure 21 to be formed as a housing for the drive device 7 . It is possible for this carrying structure 21 to embody or comprise, for example, a drive housing, in particular a transmission housing.

Illustratively, power tool 10 includes user interface 5 . This user interface 5 comprises, for example, an input device with which the user can, for example, switch on and off and/or configure and/or calibrate the power tool 10. .

As shown in FIG. 1, the power tool 10 typically rests on the work piece 11 by means of a resting surface 9 during the processing of the work piece 11 and in the feed direction 12 . , is moved relative to the workpiece 11 . Illustratively, the saw teeth of the tool 1 then saw from the bottom up into the workpiece 11 .
In this position, the tool 1 thrusts relative to the rest of the power tool 10 in the direction of the mechanical vector quantity 3 shown by way of example, i.e. at an angle. The forces emanating from the tool 1 are directed in particular in the direction of the mechanical vector quantity 3 .

Within FIG. 1, the sensor device 2 is illustratively coupled to the driven shaft 8 and the mechanical vector quantities 3 of the driven shaft 8--i.e. force, acceleration, velocity, deflection, deformation, and/or configured to detect mechanical stress.

Advantageously, the sensor device 2 is designed for continuous detection of the mechanical vector quantity 3, so that changes, in particular changes in direction of the mechanical vector quantity 3, can be detected.

The control device 4 is formed, for example, as a microcontroller. This control device 4 is designed to determine phenomena and/or states of the power tool 10 on the basis of the mechanical vector variables 3 .
For example, the controller 4 checks whether the direction of the detected mechanical vector quantity 3 lies inside or outside a predetermined range of directions, and based on this check , is configured to determine whether a given condition exists or does not exist.

Based on FIG. 2, in the following it will be explained in detail how the recognition of the identified phenomena and/or states can be exemplarily performed.

FIG. 2 shows a diagram for different orientation ranges 14 , 15 and 16 , two orientation thresholds 17 , 18 and the detected mechanical vector quantity 3 .

This diagram is divided into four quadrants. Each quadrant comprises 90°. Reference numeral 19 marks the 0° line.
The angular coordinates or angular numbers described below are to be understood mathematically in the positive direction of rotation (counterclockwise). Expediently, this 0° line runs parallel to the bearing surface 9 and/or the feed direction 12 .

The directional ranges 14, 15 and 16 are illustratively two-dimensional directional ranges. These directional ranges 14, 15 and 16 may here also be referred to as angular ranges.

Expediently, the directional ranges 14, 15, 16 lie in one plane. This plane is expediently oriented parallel to the plane of the tool 1 or perpendicular to the axial direction of the driven shaft 8 . These directional ranges 14, 15, 16 preferably do not overlap each other.

Control device 4 is formed to provide at least one directional range 14 , 15 and 16 . For example, at least one directional range is stored in a memory within this controller 4 . Alternatively or in addition to this, it is also possible for this control device 4 to likewise generate at least one directional range itself. This control device 4 is further adapted to determine whether the detected mechanical vector quantity 3 lies inside or outside the directional range 14, 15 or 16, and for this determination Based on this, the state of the power tool 10 is recognized.

Expediently, the control device 4 is arranged to provide a plurality of directional ranges 14, 15, 16 and to detect different phenomena and/or states within any one of the directional ranges 14, 15, 16. It is configured to recognize based on where the direction of the vector quantity 3 is positioned. In particular, each of these directional ranges 14, 15, 16 is then assigned a phenomenon and/or state.

When the tool 1 is being driven into the workpiece 11 and when the power tool 10 is moved relative to this workpiece 11 in the feed direction 12, the first directional range 14 is , embodying a directional range within which the mechanical vector quantity 3 is located. Illustratively, this first directional range 14 lies within both lower quadrants, i.e. within the range between 180° and 360°. In the example shown, this first range of directions 14 extends from 220° to 330°.

The mechanical vector quantity 3 located within the first direction range 14 is an indication for the presence of the phenomenon or state of forward sawing in the feed direction 12 by the power tool 10 .
Accordingly, the controller 4 recognizes that a "forward sawing-phenomenon" or "forward sawing-state" exists when the mechanical vector quantity 3 is located within the first directional range 14. is formed to

When the tool 1 is being advanced into the workpiece 11 and the power tool 10 moves relative to this workpiece 11, opposite to the standard feed direction 12, i.e. in the backward direction. , the second directional range 15 embodies a directional range within which the mechanical vector quantities are located.
When the tool 1 is driven into the workpiece 11, this second directional range 15 furthermore embodies a directional range within which the mechanical vector quantity 3 lies. Illustratively, this second directional range 15 lies within both left quadrants, ie within the range between 90° and 270°. In the example shown, this second range of directions 15 extends from 125° to 220°.

The mechanical vector quantity 3 located within the second directional range 15 is sawed backwards by the power tool 10 or the tool 1 is advanced into the workpiece 11, It is an indicator of the existence of a phenomenon or state.
Correspondingly, the control device 4 indicates that when the mechanical vector quantity 3 is located within the second direction range 15, the "reverse sawing-phenomenon" or the "reverse sawing-state" or the "incoming- It is formed to recognize that "phenomenon" exists.

The first directional range 14 and the second second directional range 15 together embody a standard range. As long as the mechanical vector quantity 3 lies within this standard range, it is possible for the control device 4 to assume that a safe operating state of the power tool 10 exists and, for example, to output a corresponding signal It is possible to provide

The third directional range 16 embodies a directional range in which the mechanical vector quantities are located in the presence of a kickback phenomenon. Illustratively, this third range of directions 16 is located in both upper quadrants, i.e. inside the range between 0° and 180°. In the example shown, this third range of directions 16 extends from 5° to 100°.
Advantageously, the control device 4 is designed to detect kickback phenomena when the mechanical vector variable 3 is located within the third directional range 16 .

The directional range over which the control device 4 estimates the kickback-phenomenon can be defined to be larger as well. For example, this directional range boundary may be located between the normal range boundary and the third directional range 16 boundary. This is illustrated by both direction thresholds 17, 18 in FIG. Illustratively, these directional thresholds 17, 18 are adjacent to the boundaries of the normal range.
Alternatively to this, these directional thresholds can likewise lie at the boundaries of the normal ranges.

Expediently, a direction range extending clockwise from the second direction threshold value 18 to the first direction threshold value 17 can be used for the position of the third direction range 16 . This third directional range 16 (illustrated in FIG. 2) is optional in this case.

Expediently, the controller 4 determines that the mechanical vector quantity 3 is between both directional thresholds 17 and 18--that is, behind the first directional threshold 17 and the second directional threshold 18 in the counterclockwise direction. It is formed to recognize the kickback phenomenon when positioned in front of and between.
This kickback-phenomenon has already been given a cause for kickback, and the power tool 10 or the workpiece 11 has however not yet been significantly accelerated or has not yet exerted any recoil or rebound. At this point, it can already be recognized.
Advantageously, the control device 4 is configured to recognize the kickback phenomenon before 50 ms to 100 ms of the occurring acceleration of the power tool 10 relative to the workpiece 11 (without recognition and reaction to the kickback). . This acceleration is, for example, an acceleration with an upward component or, within the diagram shown, a component in the 90° direction.

Alternatively or additionally to the phenomenon recognition and/or state recognition described above based on the direction of the detected mechanical vector quantity 3, the phenomenon recognition and/or state recognition can be mechanically It is equally possible to work on the basis of the direction change of the vector quantity 3 .

For example, if kickback is imminent, mechanical vector quantity 3 rotates in a direction to third directional range 16 . It is possible that the control device 4 is accordingly formed to recognize phenomena and/or states on the basis of the detected rotation of the mechanical vector quantity 3 . For example, the control device 4 is configured to compare the angular velocity of the mechanical vector quantity with a velocity threshold and to recognize phenomena and/or states when this velocity threshold is exceeded.
Furthermore, this is so that the control device 4 specifies by what angle of change the mechanical vector quantity 3 has changed, in particular within a predetermined time range, and for recognizing phenomena and/or states. It can be configured to compare the change angle with an angle threshold.

During kickback-recognition, it is possible that the control device 4 is further configured to distinguish between different modes of kickback. For example, if there is an imminent kickback that occurs during reverse sawing or entry, the mechanical vector quantity 3 rotates counterclockwise (starting from the second directional range 15), whereas Thus, this mechanical vector quantity 3 rotates clockwise during kickback induced in the workpiece 11 by the pinching of the tool 1 .
It is possible for the control device 4 to be formed accordingly such that the direction of rotation of the mechanical vector variable 3 is taken into account in the recognition of phenomena and states.

Furthermore, it is possible for the control device 4 to be designed in such a way that it also takes into account the values of the mechanical vector quantity 3 that are likewise determined during the situation recognition and/or phenomenon recognition.
For example, it is possible that the control device 4 is designed to recognize states and/or phenomena only if the value of the mechanical vector quantity 3 is greater than a certain threshold value. In this way, it can be prevented that weak impacts occurring in the operating state are erroneously recognized as kickbacks.

In addition, it is possible that the control device 4 is made to take into account the length of time that the mechanical vector quantity 3 is located inside the predetermined directional ranges 14 , 15 , 16 .
For example, the control device 4 can be configured to recognize states and/or phenomena only when the mechanical vector quantity 3 is located within a given direction range 14, 15, 16 for longer than a given time threshold. It is possible that

Furthermore, it is possible that the control device 4 is configured to determine whether a wear condition exists based on the direction of the detected mechanical vector quantity 3 . It is possible that this wear condition is in particular that of the tool 1 .
The controller 4 is configured to provide a directional range and to ascertain the wear condition based on whether the mechanical vector quantity 3 lies inside or outside the directional range. It is possible to be By way of example, the control device 4 can recognize a redirection of the mechanical vector quantity 3, eg a force redirection, and deduce the wear state from this. The control device 4 can then output, via corresponding signaling means, an acoustic or visual signal indicating that a wear condition exists.

The angular designations of the specific directional ranges 14, 15, 16 described above are to be understood as purely exemplary. Depending on the type and construction of each power tool 10, the actual angle may vary. The actual angles of these directional ranges 14, 15, 16 can be established using calibration. This calibration can be done, for example, during the development or manufacture of the power tool and/or by the user.

Advantageously, the control device 4 is designed to calibrate one or more of the directional ranges 14 , 15 , 16 . For example, using the user interface 5, this calibration can be undertaken. The control device 4 drives the tool 1 on this basis via the drive device 7 and thereby detects the mechanical vector variable 3 via the sensor device 2 .
Based on the detected mechanical vector quantity 3, the controller 4 can then create a directional range and/or one or more thresholds and, in the memory of the controller 4, Can be stored. This step can be performed, for example, when a new tool 1 is assembled. Wear recognition of the tool 1 can thus be improved.

Below, the sensor device 2 and the detection of the mechanical vector quantity 3 will be described in detail.

The sensor device 2 is expediently designed to detect the mechanical vector quantity 3 as an at least two-dimensional vector.
For this purpose, this sensor device 2 is designed to measure the mechanical quantities on which the mechanical vector quantities 3 are based in at least two different spatial directions. These two spatial directions are, for example, one spatial direction running parallel to the feed direction 12 and one spatial direction running perpendicular to this feed direction 12 .
Expediently, both spatial directions are perpendicular to the axial direction of the driven shaft 8 . For example, the sensor device 2 comprises at least two sensor elements 25,26. Expediently, each sensor element of these sensor elements 25, 26 measures the underlying mechanical quantity--force, acceleration, velocity, deflection, deformation and/or mechanical stress--by It is used for measuring in different spatial directions.

Mechanical vector quantities 3 are in particular force vectors, acceleration vectors, velocity vectors, deflection vectors, deformation vectors and/or mechanical stress vectors or stress tensors.
Accordingly, it is possible that the sensor device 2 is configured to measure forces, accelerations, velocities, deflections, deformations and/or mechanical stresses in at least two spatial directions.

It is possible for the sensor device 2 to have, in particular, a radial measuring bearing 28 by which the driven shaft 8 is supported, for example. This radial measuring bearing 28 is formed in such a way that it detects the force between the driven shaft 8 and the measuring bearing 28 as a mechanical vector quantity 3 using a force or stress sensor, for example a piezo-sensitive sensor. It is possible that

Alternatively or additionally to this, it is possible for the sensor device 2 to comprise distance sensors spaced from the driven shaft 8, which measure the deflection of the driven shaft 8 via a mechanical vector Quantity 3 is configured to detect.

Furthermore, it is possible for the sensor device 2 to comprise a stress sensor, in particular a strain gauge (DMS), in particular fixed to the carrier structure 21 .

Basically, it is possible that the sensor device 2 is arranged to measure the mechanical vector quantity 3 at a suitable part inside the transmission path of the force emanating from the tool 1 .
This force transmission path is illustratively from the tool 1 via the driven shaft 8, the bearing arrangement 27, the bearing structure 21, the housing 6 and the bearing surface 9 to the workpiece 11. Extend. In particular, the sensor device 2 is designed to measure a mechanical vector quantity 3 between two members positioned one behind the other in a force transmission path.

Figures 3 to 6 show second, third, fourth and fifth exemplary embodiments, in which the detection of the mechanical vector quantity 3 is respectively different Done in structure and manner.
With the exception of the formation and arrangement of the carrier structure 21 and the sensor device 2, the second to fifth embodiments correspond to the first embodiment described above. The features already described above in connection with this first embodiment also apply to the second, third, fourth and fifth embodiments as well.

FIG. 3 shows a power tool 20 according to a second embodiment. In this second embodiment, the sensor device 2 comprises two sensor elements 25 , 26 both of which are arranged on the carrier structure 21 . For example, these sensor elements 25 , 26 are glued to the carrier structure 21 .

These sensor elements 25 , 26 are in particular sensors for the detection of deformations of the carrier structure 21 , which deformations are induced by forces acting on this carrier structure 21 from the driven shaft 8 . These sensor elements 25, 26 are, for example, force-stress sensors, in particular strain gauges (DMS), piezo elements and/or photoconductor sensors.

Expediently, these sensor elements 25 , 26 are arranged on two portions 24 of the carrier structure 21 which extend radially outward relative to the driven shaft 8 . Illustratively, the sensor elements 25 are arranged on the horizontally extending portion 24 and the sensor elements 26 are arranged on the vertically extending portion 24 . These portions 24 are in particular web-shaped.

Part 24 expediently connects first partial section 22 and second partial section 23 of carrier structure 21 to one another. Illustratively, the first partial section 22 surrounds the driven shaft 8 . In particular, the first partial section 22 embodies or comprises a transmission housing. Advantageously, driven shaft 8 is journalled in first partial section 22 .
The second partial section 23 is expediently located behind the first partial section 22, ie downstream of this first partial section 22, in the force transmission path emanating from the tool 1. FIG.

FIG. 4 shows a power tool 30 according to a third embodiment. Expediently, the carrier structure 21 is formed as in the second embodiment described above.

In a third embodiment, the sensor device 2 comprises two sensor elements 25, 26 which are formed to detect the deflection of the driven shaft 8 in two different spatial directions. there is Advantageously, sensor element 25 detects a deflection of driven shaft 8 in a first spatial direction, and sensor element 26 is rotated relative to this driven shaft 8, in particular by 90°. Deflection in a second spatial direction is detected.

Expediently, the sensor elements 25, 26 are distance sensors, for example eddy current sensors, capacitive sensors and/or inductive sensors. In the case of an inductive sensor, it is possible that magnetic particles are arranged in or along the driven shaft 8 .

Illustratively, both sensor elements 25 , 26 are arranged on the carrier structure 21 . Expediently, the sensor elements 25 , 26 are arranged, in particular screwed, in boreholes, which are preferably provided in the carrier structure 21 . Illustratively, both sensor elements 25 , 26 are arranged on the inner partial section 22 of the carrier structure 21 .

FIG. 5 shows a power tool 40 according to a fourth embodiment. The fourth embodiment starts from the support structure 21 as described above in connection with the second embodiment, however, compared to this second embodiment, in particular in the following It has the fix described.

In the fourth embodiment, the sensor elements 25 , 26 are therefore arranged between the first partial section 22 and the second partial section 23 of the carrier structure 21 . In particular, the sensor elements 25 , 26 embody connecting elements, which mechanically connect the second partial section 23 with the first partial section 22 . Illustratively, the sensor elements 25, 26 take the place of the part 24 mentioned above in connection with the second embodiment.

Expediently, the sensor elements 25, 26 are designed as force sensors and measure the force existing between the first partial section 22 and the second partial section 23 in two different spatial directions. do. Expediently, both spatial directions are aligned perpendicular to each other. In particular, the first spatial direction extends parallel to the support surface 9 and/or the feed direction 12, and the second spatial direction extends perpendicular thereto.

According to an advantageous configuration, the first partial section 22 embodies the transmission housing and via the sensor elements 25, 26, preferably exclusively via the sensor elements 25, 26, the second partial section 23. and/or suspended on the remaining support structure 21 .

FIG. 6 shows a power tool 40 according to a fifth embodiment. Expediently, the carrier structure 21 is formed as in the second embodiment described above.

FIG. 6 shows the bearing device 27 by way of example. Expediently, this bearing arrangement 27 is arranged on the carrier structure 21 and bears the driven shaft 8 against this carrier structure 21 . This bearing arrangement 27 expediently comprises one or more bearings 31, 32, in particular radial and/or radiaxle bearings, preferably ball bearings.

Expediently, at least one bearing 31 , 32 of the bearing arrangement 27 is designed as a measuring bearing 28 , in particular a radial measuring bearing 28 , and thus embodies the sensor arrangement 2 .
Advantageously, the measuring bearing 28 is designed to measure the forces existing between the driven shaft 8 and the carrier structure 21 in at least two different spatial directions. For example, the measuring bearing 28 comprises a plurality of sensor elements, for example piezo-sensitive sensor elements, in particular piezo-sensitive thin-film sensor elements, which expediently extend in the circumferential direction of the driven shaft 8. placed around it.
In particular, these sensor elements are external bearing components of the measuring bearing 28, such as the outer ring, i.e. bearing components that are immovable relative to the carrier structure 21, or bearing structures that do not rotate with the driven shaft 8. Element -. By way of example, eight sensor elements are provided, which are each arranged offset from one another by 45°.

FIG. 7 shows the driven shaft 8 together with the two bearings 31 , 32 of the bearing arrangement 27 . Exemplarily, a first bearing 31 is arranged in the region of the distal end of the driven shaft 8 assigned to the tool 1 and a second bearing 32 is arranged opposite the tool 1 . is arranged in the region of the distal end of this driven shaft 8 on the side.

Expediently, one or both bearings 31, 32 are formed as the measuring bearings 28 described above.

Alternatively or additionally to the configurations described above, in which the sensor device 2 is integrated internally in one or more bearings 31, 32, the sensor device 2 can likewise be one or more It can also be arranged between the bearings 31 , 32 and the carrier structure 21 .

FIG. 8 shows a power tool 60 according to a sixth embodiment. Power tool 60 is here exemplarily formed as a stationary saw, in particular a table circular saw. This power tool 60 has the features already mentioned in connection with the power tool 10 above. Furthermore, it is possible in this power tool 60 for the sensor device 2 and/or the carrier structure 21 to be configured in correspondence with the second to fifth embodiments.

Illustratively, the tool 1 now rotates counterclockwise. Expediently, the workpiece 11 is pushed into the tool 1 , which is formed as a saw blade, such that during machining the saw teeth saw from above into this workpiece 11 . . The corresponding feed direction 12 is shown in FIG. Orientation ranges 14 , 15 , 16 and/or orientation thresholds 17 , 18 are adapted accordingly in power tool 60 . For example, it is possible that the directional ranges 14, 15, 16 and/or the directional thresholds 17, 18 shown in FIG. 2 are symmetrical about the center point of the diagram.

In the following, various possibilities of how a perceived phenomenon and/or a perceived state can be responded to are mentioned. Expediently, it is possible that each possibility is implemented in each of the power tools mentioned above.

Advantageously, the control device 4 is designed to provide corresponding signals in response to recognized phenomena and/or conditions. It is possible for the control device 4 to be configured, for example, to store this signal in a memory and/or to output it, in particular via acoustic or visual signal output means of the power tool. be.
The stored signal can in particular be a data record in which the data detected by the sensor device 2 are recorded. What is being dealt with here is, for example, data recording for the purposes of accident course detection.

In order to cause, for example, that the tool 1 is no longer driven and/or is braked, in particular fully braked, the control device 4 can also control the movement of the drive 7 in response to the recognized phenomena and/or conditions. It is possible that it is configured to perform certain controls. This is particularly useful when the perceived phenomenon is the kickback-phenomenon.
This braking can then in particular be effected by the same electric motor by which the tool 1 is otherwise driven.

Alternatively or additionally, the power tool can be provided with braking means and the control device, in response to a recognized phenomenon and/or signal, activates this braking means when the tool 1 is braked. It is possible that it is configured to control to some extent.

Expediently, the control device 4 controls the braking of the tool 1 via the drive 7 and/or the braking means in the event of a recognized kickback-phenomenon as well as any recoil of the power tool and/or the workpiece 11 . Alternatively, it is formed so as to occur at a point in time when rebounding is not performed.
For example, returning to FIG. 2, this braking can take place at a time when the directional threshold 17 or 18 has already been exceeded and the mechanical vector variable 3 is advantageously however not yet located within the third directional range 16. .
In this way, recoil or rebound caused by kickback can be reduced or completely prevented.

Furthermore, the power tool 10, 60 can be provided with a positioning device 29, which is configured to selectively position the tool 1 in an operating position or a safety position. It is possible that the control device 4 is configured to control this positioning device 29 in response to recognized phenomena and/or conditions, so that the tool 1 is positioned in the operating position or in the safeguarding position. be done.
The positioning device 29 is formed, for example, to move and/or pivot the tool 1 between an operating position and a safety position. Expediently, the tool 1 is positioned farther into the housing 6 in the safety position than in the operating position. Expediently, the tool 1 is positioned in a safe position in response to a kickback-event.

FIG. 9 shows a flowchart of a method for phenomenon and/or status recognition of a power tool 10, 20, 30, 40, 50, 60 having a rotatable tool 1 formed as a saw blade or milling cutter. showing.
The method comprises a step S1 of detection of mechanical vector quantities 3, i.e. forces, accelerations, velocities, deflections, deformations and/or mechanical stresses, which depend on the force emanating from the tool 1; recognizing the phenomenon and/or state of the power tool according to the direction and/or direction change of the mechanical vector quantity 3 .

30; 40; 50; 60 described above.

Advantageously, the method comprises a further step in which one of the previously mentioned reactions to the recognized phenomenon and/or the recognized state is performed. .
Although the present application relates to the invention described in the claims, it can also include the following as other aspects.
1. A power tool (10, 20, 30, 40, 50, 60) having a rotatable tool (1) formed as a saw blade or milling cutter, the power tool comprising
comprising a sensor device (2) for detection of a mechanical vector quantity (3);
This mechanical vector quantity (3) comprises force, acceleration, velocity, deflection, deformation and/or mechanical stress, and this mechanical vector quantity (3) comprises said saw blade ( 1) depending on the force emanating from
and the power tool is
a control device (4) communicatively coupled with said sensor device (2);
The control device controls the phenomenon and/or state of the power tool (10; 20; 30; 40; 50; 60) in the direction of the mechanical vector quantity (3) detected by the sensor device (2). and/or configured to recognize according to direction changes,
A power tool characterized by:
2. Said controller (4) controls the phenomena and/or conditions to be recognized such as kickback, forward sawing, backward sawing, entry of said tool (1) into workpiece (11), and/or , configured to recognize the state of wear of said power tool (10; 20; 30; 40; 50; 60), in particular said tool (1),
20; 30; 40; 50; 60).
3. Said controller (4) is adapted to provide at least one directional range (14, 15, 16) and to indicate said phenomena and/or states that the direction of said mechanical vector quantity (3) is in said direction configured to recognize based on whether it lies inside or outside the range (14, 15, 16);
3. The power tool (10; 20; 30; 40; 50; 60) according to 2 above, characterized in that:
4. Said controller 4 is adapted to provide a plurality of directional ranges (14, 15, 16) and to detect different phenomena and/or conditions within any of said directional ranges (14, 15, 16). configured to recognize based on where said direction of said mechanical vector quantity (3) is located in
4. The power tool (10; 20; 30; 40; 50; 60) according to 2 or 3 above, characterized in that:
5. said control device 4 is configured to calibrate one or more directional ranges (14, 15, 16);
5. The power tool (10; 20; 30; 40; 50; 60) according to 3 or 4 above, characterized in that:
6. The controller 4 is configured to recognize the phenomenon and/or state based on the angular velocity and/or angle of change of the mechanical vector quantity (3),
6. The power tool (10; 20; 30; 40; 50; 60) according to any one of 2 to 5 above, characterized in that:
7. The sensor device (2) comprises a first sensor element (25) and a second sensor element (26),
said first sensor element (25) is configured to measure a mechanical quantity underlying said mechanical vector quantity (3) in a first spatial direction, and
Said second sensor element (26) is configured to measure the mechanical quantity underlying said mechanical vector quantity (3) in a second spatial direction different from this first spatial direction. has been
7. The power tool (20; 30; 40) according to any one of 2 to 6 above, characterized in that: 8. Said power tool (20; 30; 40) further comprises a bearing structure (21) and a driven shaft (8) journalled in said bearing structure (21) with which said tool is connected. A power tool (20; 30; 40) according to Claim 7, characterized in that the sensor element (25, 26) is arranged on this carrier structure (21).
9. Said carrying structure (21) comprises a first partial section (22), in particular a transmission housing, and a second partial section (23), and
both sensor elements (25, 26) are each formed as a connecting element between the first partial section (22) and the second partial section (23),
9. The power tool (40) according to the above 8, characterized in that:
10. 10. Power tool (50) according to any one of claims 2 to 9, characterized in that the sensor device (2) comprises a measuring bearing (28).
11.
said controller (4) is configured to provide a signal in response to said recognized phenomenon and/or said recognized state;
11. The power tool (10; 20; 30; 40; 50; 60) according to any one of 2 to 10 above, characterized in that:
12. The power tool (10; 20; 30; 40; 50; 60) comprises a drive (7) for driving the tool (1), and
In order to vary the drive of the tool (1), in particular to brake the tool (1), the control device (4) may, in response to the recognized phenomenon and/or the recognized state, change this configured to control the drive (7),
12. The power tool (10; 20; 30; 40; 50; 60) according to any one of 2 to 11 above, characterized in that:
13. Said power tool comprises a positioning device (29), said positioning device:
configured to selectively position the tool (1) in an operating position or a safety position; and
Said control device (4) is arranged to control said positioning device (29) in response to said recognized phenomenon and/or said recognized condition, so that said tool (1): positioned in the operating or safety position,
(10;60) according to any one of the above 1 to 12, characterized in that
14. A method for the recognition of phenomena and/or states of a power tool (10, 20, 30, 40, 50, 60) having a rotatable tool (1) formed as a saw blade or milling cutter, , the method includes the following steps:
a step (S1) of detection of a mechanical vector quantity (3), wherein the mechanical vector quantity (3) is a force, acceleration, velocity, displacement, deformation and/or mechanical stress and this mechanical vector quantity (3) depends on the force emanating from said saw blade (1) (S1);
Recognition of said phenomenon and/or state of said power tool (10; 20; 30; 40; 50; 60) according to the sensed direction and/or direction change of said mechanical vector quantity (3). (S2);
A method comprising:

REFERENCE SIGNS LIST 1 tool 2 sensor device 3 mechanical vector quantity 4 control device 5 user interface 6 housing 7 drive device 8 driven shaft
9 placement surface 10 power tool 11 material to be processed 12 feed direction 14 direction range, first direction range 15 direction range, second direction range 16 direction range, third direction range 17 direction threshold, first direction threshold 18 orientation threshold, second orientation threshold 19 0° line 20 power tool 21 carrying structure 22 first partial section, inner partial section 23 second partial section 24 section 25 sensor element, first sensor element 26 sensor element, second sensor element 27 bearing arrangement 28 measuring bearing, radial measuring bearing 29 positioning device 30 power tool 31 bearing, first bearing 32 bearing, second bearing 40 power tool 50 power tool 60 power tool S1 step S2 step

Claims (16)

A power tool (10, 20, 30, 40, 50, 60) having a rotatable tool (1) formed as a saw blade or milling cutter, the power tool comprising
comprising a sensor device (2) for detection of a mechanical vector quantity (3);
This mechanical vector quantity (3) comprises forces, accelerations, velocities, deflections, deformations and/or mechanical stresses, and this mechanical vector quantity (3) comprises said tool (1 ), depending on the force emanating from
the direction of the detected vector quantity coincides with the direction in which the tool (1) advances relative to other components of the power tool (10, 20, 30, 40, 50, 60);
and the power tool is
a control device (4) communicatively coupled with said sensor device (2);
The control device controls the phenomenon and/or state of the power tool (10; 20; 30; 40; 50; 60) to the mechanical vector quantity (3) detected by the sensor device (2). configured to recognize according to direction and/or direction change,
A power tool characterized by: Said controller (4) controls the phenomena and/or conditions to be recognized such as kickback, forward sawing, backward sawing, entry of said tool (1) into workpiece (11), and/or , configured to recognize the state of wear of said power tool (10; 20; 30; 40; 50; 60), in particular said tool (1),
A power tool (10; 20; 30; 40; 50; 60) according to claim 1, characterized in that: Said controller (4) is adapted to provide at least one directional range (14, 15, 16) and to indicate said phenomena and/or states that the direction of said mechanical vector quantity (3) is in said direction configured to recognize based on whether it lies inside or outside the range (14, 15, 16);
A power tool (10; 20; 30; 40; 50; 60) according to claim 2, characterized in that: Said controller 4 is adapted to provide a plurality of directional ranges (14, 15, 16) and to detect different phenomena and/or conditions within any of said directional ranges (14, 15, 16). configured to recognize based on where said direction of said mechanical vector quantity (3) is located in
A power tool (10; 20; 30; 40; 50; 60) according to claim 2 or 3, characterized in that: said control device 4 is configured to calibrate one or more directional ranges (14, 15, 16);
A power tool (10; 20; 30; 40; 50; 60) according to claim 3 or 4, characterized in that: The controller 4 is configured to recognize the phenomenon and/or state based on the angular velocity and/or angle of change of the mechanical vector quantity (3),
A power tool (10; 20; 30; 40; 50; 60) according to any one of claims 2 to 5. The sensor device (2) comprises a first sensor element (25) and a second sensor element (26),
said first sensor element (25) is configured to measure a mechanical quantity underlying said mechanical vector quantity (3) in a first spatial direction, and
Said second sensor element (26) is configured to measure the mechanical quantity underlying said mechanical vector quantity (3) in a second spatial direction different from this first spatial direction. has been
A power tool (20; 30; 40) according to any one of claims 2 to 6, characterized in that: Said power tool (20; 30; 40) further comprises a bearing structure (21) and a driven shaft (8) journalled in said bearing structure (21) with which said tool is connected. 8. Power tool (20; 30; 40) according to claim 7, characterized in that the sensor element (25, 26) is arranged on this carrier structure (21). Said carrying structure (21) comprises a first partial section (22) and a rearward of said first partial section (22) in the transmission path of forces emanating from said tool (1), ie this first partial section. a second sub-section (23) located downstream of (22); and
both sensor elements (25, 26) are each formed as a connecting element between the first partial section (22) and the second partial section (23),
A power tool (40) according to claim 8, characterized in that: Power tool (50) according to any one of claims 2 to 9, characterized in that the sensor device (2) comprises a measuring bearing (28). said controller (4) is configured to provide a signal in response to said recognized phenomenon and/or said recognized state;
A power tool (10; 20; 30; 40; 50; 60) according to any one of claims 2 to 10. The power tool (10; 20; 30; 40; 50; 60) comprises a drive (7) for driving the tool (1), and
In order to vary the drive of the tool (1), in particular to brake the tool (1), the control device (4) may, in response to the recognized phenomenon and/or the recognized state, change this configured to control the drive (7),
A power tool (10; 20; 30; 40; 50; 60) according to any one of claims 2 to 11. Said power tool comprises a positioning device (29), said positioning device:
configured to selectively position the tool (1) in an operating position or a safety position; and
Said control device (4) is arranged to control said positioning device (29) in response to said recognized phenomenon and/or said recognized condition, so that said tool (1): positioned in the operating or safety position,
13. A power tool (10; 60) according to any one of the preceding claims. A power tool (40) according to claim 9, characterized in that said first section (22) is a transmission housing. A method for the recognition of phenomena and/or states of a power tool (10, 20, 30, 40, 50, 60) having a rotatable tool (1) formed as a saw blade or milling cutter, , the method includes the following steps:
A step (S1) of detection of a mechanical vector quantity (3), wherein said mechanical vector quantity (3) is a force, acceleration, velocity, deflection, deformation and/or mechanical stress and this mechanical vector quantity (3) depends on the force emanating from said tool (1),
At that time, the direction of the detected vector quantity coincides with the direction in which the tool (1) moves relative to other components of the power tool (10, 20, 30, 40, 50, 60). do,
and,
of the recognition of said phenomenon and/or state of said power tool (10; 20; 30; 40; 50; 60) according to said direction and/or direction change of said detected mechanical vector quantity (3); a step (S2);
A method comprising: A power tool (10, 20, 30, 40, 50, 60) having a rotatable tool (1) formed as a saw blade or milling cutter, the power tool comprising
comprising a sensor device (2) for detection of a mechanical vector quantity (3);
This mechanical vector quantity (3) comprises forces, accelerations, velocities, deflections, deformations and/or mechanical stresses, and this mechanical vector quantity (3) comprises said tool (1 ), depending on the force emanating from
and the power tool is
a control device (4) communicatively coupled with said sensor device (2);
The control device controls the phenomenon and/or state of the power tool (10; 20; 30; 40; 50; 60) in the direction of the mechanical vector quantity (3) detected by the sensor device (2). and/or configured to recognize according to direction changes;
The control device (4) detects that the phenomena and/or conditions to be recognized include kickback, forward sawing, reverse sawing, entry of the tool (1) into the workpiece (11), and/or , being configured to recognize the state of wear of said power tool (10; 20; 30; 40; 50; 60), in particular said tool (1);
said sensor device (2) comprising a first sensor element (25) and a second sensor element (26),
said first sensor element (25) is configured to measure a mechanical quantity underlying said mechanical vector quantity (3) in a first spatial direction, and
Said second sensor element (26) is configured to measure the mechanical quantity underlying said mechanical vector quantity (3) in a second spatial direction different from this first spatial direction. is being done,
The power tool (20; 30; 40) further comprises a bearing structure (21) and a driven shaft (8) journalled in the bearing structure (21), with which the tool is connected. and said sensor elements (25, 26) are arranged on said carrier structure (21); and
Said carrying structure (21) comprises a first partial section (22), i.e. the transmission housing,
A second partial section ( 23) and
both sensor elements (25, 26) are each formed as a connecting element between the first partial section (22) and the second partial section (23);
A power tool characterized by: