Device and method for determining the profile of a cutting edge

Abstract

The invention relates to a device (1) and a method for determining a profile of a cutting edge (2). The invention is based on the objective of providing a device (1) and a method that enable a simple and accurate determination of a cutting edge profile. The problem is solved by the device comprising a force measuring device (3) and a processing unit (4). The force measuring device (3) is configured to measure a force exerted on it by the cutting edge (2). The processing unit (4) is configured to receive a measurement signal from the force measuring device (3) and to calculate the profile of the cutting edge (2) based on this signal.

Description

[0001] The invention relates to a device for determining the profile of a cutting edge, comprising a force measuring device and a computing unit. The invention further relates to a method for determining the profile of a cutting edge, which includes providing a device as described herein.

[0002] Knives and blades are frequently manufactured by machine, and especially fully automatically. Some knives and blades are subject to special requirements. In particular, these knives and blades often have an edge with a specific geometry and, especially, a special cross-sectional profile. The edge is a component of a blade and a knife, as described below.

[0003] A knife typically consists of a handle and a blade. The blade can be made of a metal, a ceramic, or a composite material, for example. The blade has a flat surface and an edge, usually located at one of its outer edges. In cross-sectional view, the blade typically has symmetrical and often parallel flanks with respect to a central axis. The edge, in cross-sectional view, regularly features a cutting wedge, which has at least two cutting edges located on the wedge's flanks and angled relative to the blade's central axis at a so-called grinding angle. It also has a cutting edge with a defined radius and width.The cutting edge can be created, for example, by a grinding process in which material is removed from a blade blank, thus shaping the blank section by section into a geometry characteristic of a cutting edge. In a single-bevel grind, the cutting edge has two cutting flanks. In a multi-bevel grind, the cutting edge can have more than two cutting flanks, in particular four, six, or eight. With respect to the extended central axis of the blade in the cross-sectional view, which is extended to the cutting edge, opposing cutting flanks can be symmetrical or asymmetrical. The cutting flanks can have any contour in the cross-sectional view of the cutting edge. In particular, the cutting flanks in the cross-sectional view can be straight, convex, concave, or in the shape of a Gothic arch.

[0004] Determining the profile of the cutting edge of a manually or machine-made blade or knife is only possible with considerable effort. However, determining the profile—that is, determining the geometric shape of the cutting edge in a cross-sectional view—can be advantageous despite the considerable effort, especially for knives and blades with specific requirements. This is particularly useful, for example, to detect deviations from the specified geometry due to errors in the manufacturing process. Knives and blades where the cutting edge profile demonstrably adheres to the design specifications can ideally meet these specific requirements. Therefore, it is desirable to be able to determine the profile of a cutting edge, and in particular the grinding angles of the cutting edges, the height of the cutting edges, the contour of the cutting edges in cross-section, and / or the width of a cutting wedge.

[0005] Current technology offers comparatively less robust, mostly costly and / or inadequate measuring devices and methods for determining a profile or individual parameters of a cutting edge profile.

[0006] For example, laser goniometers are known from the prior art. Laser goniometers are used to measure the grinding angle of the cutting edges. For this purpose, a knife is inserted into the laser goniometer with its cutting edge facing a laser source. A laser beam is reflected off the cutting edges and onto a scale, allowing the grinding angle of the cutting edges to be read. The measurement with a goniometer is limited exclusively to measuring the foremost grinding angle with an accuracy of ± 1°. Furthermore, it is known in the prior art to cut a blade to produce a cross-section. This cross-section can then be examined using a microscope. The microscopes required for evaluating a cutting edge are expensive and not very robust, or rather, unsuitable for use in a manufacturing environment.Furthermore, generating a cross-section of a cutting edge and microscopically determining the profile are complex processes. Profilometers for determining microscopic or submicroscopic surface topographies along a straight and essentially flat measuring path are also known in the prior art. Profilometers only allow the measurement of one side of the cutting edge, are also expensive, and are not sufficiently robust for use in a production environment, and are therefore unsuitable for determining the profile of a cutting edge.

[0007] US patent 2020 / 0246933 A1 discloses an automatic knife sharpening machine that may include a vise for clamping a knife blade and a pair of grinding wheels for removing material from the blade. The machine may include a measuring device for determining the profile of a blade edge and a sharpness sensor for determining the edge's degree of sharpness. The machine may also include a control unit. Using the sharpness sensor, the control unit can determine the edge's sharpness after the first sharpening pass and perform at least one second sharpening pass if the determined sharpness falls below a sharpness threshold.

[0008] US patent 2019 / 0126423 A1 discloses a variant of a method for automatically resharpening a knife.

[0009] The invention is based on the objective of providing a device and a method that enable the simple and accurate determination of a cutting edge profile. In particular, the device and the method should be robust so that their reliable application in industrial environments is possible.

[0010] The problem is solved according to the invention by the features of the independent claims. Further practical embodiments and advantages of the invention are described in connection with the dependent claims.

[0011] The device described here for determining the profile of a cutting edge comprises a force measuring device and a processing unit. The force measuring device is configured to measure a force exerted on it by the cutting edge. The processing unit is configured to receive a measurement signal from the force measuring device and to calculate the profile of the cutting edge based on this signal. In particular, the processing unit is configured to receive a measurement signal from the force measuring device that was generated as a result of a force exerted on it by the cutting edge, and to calculate the profile of the cutting edge and / or at least one characteristic value describing the profile of the cutting edge based on this measurement signal.

[0012] The invention is based on the fundamental idea of ​​determining the profile of a cutting edge using a force measuring device. Starting with a force measured by the force measuring device, the computing unit can easily calculate a displacement in the direction in which the force acts on the force measuring device. If, as is possible with the device described here, a force acting from the cutting edge onto the force measuring device is measured at a plurality of positions on the cutting flanks of a cutting edge, a displacement can be calculated at each of these positions. Based on the plurality of displacements calculated at the cutting flanks, it is possible to reconstruct a profile of the cutting edge and / or to calculate at least one characteristic value describing the profile of the cutting edge.

[0013] The force measuring device includes, in particular, at least one force sensor configured to measure the force exerted by the cutting edge on the force measuring device. The force measuring device and the force sensor can, in particular, be configured and arranged in the device such that the force measuring device, and especially the force sensor, is movable in a direction of movement relative to the cutting wedge of a knife or edge whose cutting profile is to be determined.

[0014] Force measuring devices allow for extremely precise force measurement and can also be extremely robust. Therefore, combining a force measuring device with a computing unit is ideally suited for developing the device described here for determining the profile of a cutting edge. This device enables the profile of a cutting edge to be determined simply and accurately in an industrial environment.

[0015] In practice, the device can include a drive unit. The drive unit is configured to move the cutting edge, whose profile is to be determined, along a direction of movement relative to the force measuring device. Alternatively, the drive unit is configured to move at least one component of the force measuring device relative to the cutting edge along the direction of movement. In other words, the drive unit can move either the cutting edge or a component of the force measuring device, for example, the force sensor or an element supporting the force sensor, relative to the other of these two components of the device.

[0016] The direction of movement can, for example, be the direction in which the central axis of the blade is oriented. Alternatively, the direction of movement can be a direction that deviates from the direction of the central axis by an angle, in particular by a smaller angle than the grinding angle of the cutting edges. Due to movement along the direction of the central axis of the blade or along a direction that deviates from this direction by no more than the grinding angle, the force measuring device, and in particular the force sensor, can be positioned simply and accurately at a plurality of positions on the cutting edges of a blade. At these plurality of positions, a force acting from the blade on the force measuring device can be measured.Due to its movement in the direction of motion, the cutting edge exerts different forces on the force measuring device at different positions along the cutting flanks. These varying forces are measured. From these measured forces, different displacements in the direction in which the force acts on the force measuring device are calculated. A profile of the cutting edge is then determined from these calculated displacements in the direction in which the force acts on the force measuring device.

[0017] The drive unit can include a drive that can be manually controlled by an operator of the device. Preferably, the drive unit can include an electric drive for executing the movement along the direction of motion, which can further preferably be controlled by the computing unit.

[0018] Additionally or alternatively, the device can include a displacement sensor. The displacement sensor is designed to measure the distance of a relative movement between the cutting edge and at least one component of the force measuring device along a direction of movement. Advantageously, the displacement sensor can detect the distance of a movement of the cutting edge or the component of the force measuring device generated, for example, by the drive unit. The detected distance can be transmitted from the displacement sensor to the processing unit. The processing unit can be configured such that the detected distance is automatically linked to the measurement signal from the force measuring device and / or to the calculated displacement. Due to this automatic linking, it is possible to easily acquire a large number of measurement results for calculating the profile of a cutting edge along its cutting flanks.The linked measurement results can be saved on a data carrier and retrieved by an operator of the device.

[0019] The device may also include a means for the optical output of information, such as a display. This means of optical output can display, for example, the measurement results obtained with the components of the device, the calculated displacements, the linked data, or a combination of at least some of the aforementioned. In particular, it may be possible to display an enlarged graphical reconstruction of the determined profile based on the calculation of the cutting edge profile using the means of optical output. The operator of the device can then perceive the geometric shape of the cutting edge's cross-section at a glance. The geometric shape of the cutting edge's cross-section often already contains much information relevant to the operator regarding the profile.For example, it is immediately apparent whether the profile is symmetrical or asymmetrical and / or what the height of the cutting edges is in relation to the width of the cutting wedge. Alternatively and / or additionally, the optical display can show at least one characteristic value that describes the cutting edge profile.

[0020] In practice, the force measuring device can have two opposing contact elements that can be separated, at least partially. A contact element is a component of the force measuring device that comes into contact with the cutting edge, whose profile is to be determined, when the cutting edge profile is being determined. The opposing contact elements can be arranged in contact with each other or spaced apart, with the distance between them being less than the width of a cutting wedge of a blade or knife. During the intended use of the device comprising the contact elements, the cutting edge comes into contact with both contact elements. At least one of the two opposing contact elements is designed such that at least a section of this contact element can be pushed away from the other contact element when a force is exerted on the contact elements by the cutting edge.This force can be exerted, for example, when the cutting edge or the force measuring device are moved relative to each other in a direction of movement which may be oriented, for example, along the direction of the central axis of the blade or along a direction that deviates from this direction by no more than the grinding angle of the cutting edge.

[0021] If at least one section of at least one of the two opposing system elements is pushed away from the other system element, a displacement of that section occurs in the direction in which the force acts on the system element. This displacement can be calculated by the processing unit based on the force measuring the displacement, as measured by the force sensor.

[0022] When the force measuring device with the section of the displaceable attachment element on the surface of the cutting flanks is moved in the direction of movement relative to the cutting edge, the displacement of the displaced section calculated along the direction of movement corresponds to the contour of the profile of the cutting edge.

[0023] In practice, at least one of the system components can have an elongated deflection element with a first end and a second end in a principal direction of extension. The first end is mounted on a support, and the second end is deflectable.

[0024] As intended, a blade may be positioned with its cutting edge, and in particular its cutting edge, at the second end of the deflection element. If, starting from this arrangement, the cutting edge is moved relative to the deflection element in the direction of movement, or if the deflection element is moved relative to the cutting edge in the direction of movement, the second end of the deflection element scans a cutting flank of the cutting edge. The cutting edge exerts a force on the deflection element, such that at least the second end, which is in contact with the cutting flank, is pushed away from the opposite contact element. The force sensor can, for example, be arranged on the elongated deflection element and measure the bending of the deflection element at the sensor location, which is caused by the force exerted on the contact element.

[0025] A structurally simple design of the deflection element described here could, for example, be an elongated rod with an essentially rectangular cross-section.

[0026] It is possible that only one of the two support elements has the deflection element. Alternatively, both support elements can have the deflection element. If both support elements have the deflection element, the second end of each of the two deflection elements can be deflected away from the cutting edge. If only one of the two support elements has the deflection element, the other support element can, for example, be designed as a rigid component with a guide surface oriented towards the support element designed as the deflection element. A blade flank or a cutting edge of a knife, the profile of which is to be determined, can be applied to this guide surface. In particular, the guide surface can be flat.When a blade flank of a blade with two parallel blade flanks is applied to the flat guide surface, the central axis of the blade is arranged parallel to the direction of extension of the guide surface. Advantageously, movement of the cutting edge or the force measuring device in the direction of movement can occur parallel to the guide surface, and a force exerted by the cutting edge on the deflection element can, in particular, be transverse to the plane of extension of the guide surface.

[0027] Optionally, at least one of the two system elements, in particular a system element with a deflection element at the second end, may have a probe element, which may, for example, be in the form of a measuring tip.

[0028] If both system components include the deflection element, the two deflection elements can be designed and / or arranged symmetrically to each other. In particular, a force sensor can be arranged on each of the two deflection elements. Additionally or alternatively, the deflection elements can be designed such that both deflection elements are movable together in the direction of movement relative to the cutting edge. Consequently, the deflection elements do not move relative to each other during movement in the direction of movement. Such a design allows for particularly rapid determination of cutting edge profiles with a symmetrically designed profile. This is because a symmetrically designed cutting edge causes the same displacement at the second end of both deflection elements in this case.

[0029] In practice, the at least one deflection element can be an elastically deformable bending element, with the first end fixed to the holder in a rotationally fixed manner. In this case, if a cutting edge exerts a force on the second end, the second end is displaced in a direction transverse to the direction of movement, thereby elastically bending the bending element. Alternatively, the at least one deflection element can be a rigid deflection element, with the first end rotatably mounted on the holder. If the deflection element is designed as a rigid deflection element, the mounting element additionally has a pivot joint mechanically connecting the deflection element and the holder, allowing the deflection element to pivot. In this case, if a cutting edge exerts a force on the second end, the second end is displaced in a direction transverse to the direction of movement, thereby pivoting the bending element about the pivot joint.

[0030] If the deflection element is an elastically deformable bending element, the processing unit can be configured to calculate a deflection curve of the elastically bent deflection element, or at least individual points on the deflection curve, based on the force acting on the force measuring device. If the deflection element is a rigid deflection element, the processing unit can be configured to calculate a pivot angle of the deflection element pivoted about its first end, based on the force acting on the force measuring device.

[0031] As described in this application, the force measuring device can include a force sensor. If the deflection element is an elastically deformable bending element, the force sensor can preferably be designed as a strain gauge arranged on the bending element. More preferably, the strain gauge can be arranged at a position of the deflection element where the deflection element has a reduction in cross-section, for example, in the form of a recess or a notch. Additionally or alternatively, the deflection element can be designed as a load cell with a force sensor designed as a strain gauge. By elastically bending the deflection element in a direction transverse to the direction of movement, a force sensor designed as a strain gauge is stretched or compressed. This stretching or compression can correlate with bending of the deflection element in the region of the strain gauge.Based on the determined bending and the known geometry of the deflection element, the deflection curve of the deflection element or at least the displacement of the second end of the deflection element can be calculated using the computing unit.

[0032] In a rigid deflection element that is pivotably arranged around the pivot joint, the force sensor can be located, in particular, at the pivot joint. By pivoting the deflection element in a direction transverse to the direction of movement, a force sensor, which is designed, in particular, as a strain gauge and is arranged at the pivot joint, is stretched or compressed. This stretching or compression can correlate, in particular, with the pivot angle. Based on the determined pivot angle and the known geometry of the deflection element, the displacement of the second end of the deflection element can be calculated using the processing unit.

[0033] In practice, the at least one deflection element can have two elongated sections in the principal direction of extension, with the first section comprising the first end and the second section comprising the second end, the first section being stiffer than the second section. The first and second sections can, in particular, be arranged linearly adjacent to each other in the principal direction of extension. Due to the higher stiffness of the first section, it can only be deflected with a greater force than the second section. The higher stiffness of the first section can be achieved, for example, by the first section having a higher area moment of inertia than the second section, and / or by the elastic modulus of the material from which the first section is formed being greater than the elastic modulus of the material from which the second section is formed.Constructing the deflection element from two elongated sections allows the use of commercially available load cells in the device described here for measuring the force exerted by the cutting edge on the force measuring device. Commercially available load cells can occasionally be so rigid that their use as a deflection element can cause scratching of the cutting edge or damage to the load cell due to excessive deflection and / or bending. Combining a commercially available load cell as the first section with a less rigid second section, which bends more easily in contact with the cutting edge than the commercially available load cell, allows measurement of the cutting edge profile without scratching it or overloading the load cell. The bending of the second section is greater than that of the first section, on which the force sensor can preferably be arranged.In particular, the deflection curve of the second section can be known as a function of the force measured with the bending of the first section, and thus even with a small bending of the first section a comparatively large displacement of the second end of the deflection element can be calculated using the computing unit.

[0034] Additionally or alternatively, it is also possible that the first section is formed as a rigid deflection element, with the first end rotatably mounted on the bracket, and the second section is formed as a bending element.

[0035] In practice, the device can include a holding device. The holding device is designed to hold a blade with the cutting edge whose profile is to be determined. In particular, the holding device is designed to securely hold a blade in a predetermined position relative to the force measuring device. The holding device can, in particular, include at least one magnet. A blade made of a magnetic material can be easily held by the holding device by the magnet. To protect the blade, the magnet can, in particular, have a protective layer of rubber.

[0036] If the second support element is designed as the rigid component with a guide surface, particularly a flat one, oriented towards the support element designed as a deflection element, the holding device can be integrated into the second support element. For example, the at least one magnet can be arranged on the component such that a surface of the magnet is flush with the guide surface. Alternatively, the holding element can be designed as a separate component from the two support elements in the device. The holding element can then be designed and arranged such that a knife or blade arranged on the holding element, as intended, bears with its cutting edge against the force measuring device, preferably against the support elements, more preferably against the deflection elements, and even more preferably against the sensing elements.

[0037] In practice, the holding device can include an adjusting device. The adjusting device is designed to position a blade held by the holding device, with its cutting edge (the profile of which is to be determined) in an adjustable position along an adjustment direction. The adjustment direction is different from the direction of movement and, in particular, is oriented orthogonally to it. Furthermore, the adjustment direction is, in particular, at least substantially, oriented perpendicular to the blade of a blade held in the holding device. For positioning along the adjustment direction, the adjusting device can include a drive, for example, in the form of an adjusting screw. If the holding device includes a magnet, this magnet can be moved along the adjustment direction, for example, by means of the drive, which is designed, in particular, as an adjusting screw.Additionally or alternatively, the adjusting device may have at least one ball head and / or a gimbal suspension with which the adjusting device and thus a blade arranged on the adjusting device can be balanced.

[0038] The invention also relates to a method for determining the profile of a cutting edge. The method comprises the following steps: • Provide a device described here; • Positioning a blade with the cutting edge, whose profile is to be determined, on the force measuring device; • Moving the force measuring device and / or the blade with the cutting edge in relation to each other and thereby exerting a force with the cutting edge on the force measuring device; • Measuring the force exerted by the cutting edge on the force measuring device using the force measuring device; • Transmitting the measurement signal from the force measuring device to the computing unit and calculating the profile of the cutting edge and / or at least one characteristic value describing the profile of the cutting edge based on the measurement signal.

[0039] With regard to the method described here, reference is also made to the description of the device, which can be applied analogously to the features of the method.

[0040] In practice, the device may be provided to have two opposing support elements, with the blade being arranged with the cutting edge on the support elements in such a way that these support elements are pushed apart at least section by section by a relative movement of the blade and / or at least one of the support elements to each other.

[0041] The calculation of the cutting edge profile and / or at least one characteristic value describing the cutting edge profile in the processing unit 3 is performed, in particular, on the basis of a calibration. The calibration can be based on the measurement of at least one physical embodiment with the device.

[0042] Calibration can be performed by measuring at least one, preferably multiple, physical dimensions with known dimensions using the device. The physical dimensions are selected to ensure that the device's measuring range is representatively covered. A characteristic curve can then be derived from the various measured values ​​obtained. This characteristic curve illustrates, in particular, the relationship between the values ​​measured by the force measuring device and the underlying displacement of the relevant system element. During subsequent measurements, the cutting edge profile and / or at least one characteristic value describing the cutting edge profile are determined from the electrical signal value of the force measuring device's sensor, based on the characteristic curve.

[0043] Reference is also made to the description of the device with regard to this development of the method, which can be applied analogously to the features of the method.

[0044] Further practical embodiments and advantages of the invention are described below in connection with the drawings. They show: Fig. 1 a schematic representation of a knife blade; Fig. 2 a schematic representation of a first embodiment of the device according to the invention for determining a profile of a cutting edge and a blade in a state before the start of a profile determination; Fig. 3 the in Fig. 2 first embodiment of the device according to the invention and the blade in a state during a profile determination; Fig. 4 a schematic representation of a second embodiment of the device according to the invention for determining a profile of a cutting edge and a blade in a state before the start of a profile determination; Fig. 5 the in Fig. 4 shown second embodiment of the device according to the invention and the blade in a state during a profile determination; Fig. 6 a representation of a third embodiment of the device according to the invention for determining a profile of a cutting edge in a state before the start of a profile determination in a side oblique top view; Fig. 7 the device from Fig. 6 in a front view; Fig. 8 the device from Fig. 6 in a front view at an angle from above; Fig. 9 the device from Fig. 6 in a top view; Fig. 10 the upper part of the device made of Fig. 6 in a side oblique top view with a blade arranged on the device; Fig. 11 the device from Fig. 6 in a side oblique top view with a blade arranged on the device without the housing and without the holding device.

[0045] In the Fig. Reference symbols 1 to 11, found in different figures, denote identical or functionally equivalent technical elements or process steps. For clarity, not all reference symbols are shown in the figures, although the elements may still be present.

[0046] Fig. Figure 1 shows a schematic representation of a knife blade. The blade can be made of knife steel, for example. The blade has a flat blade a and an edge b formed at an outer edge of the blade a. In a cross-sectional view, the blade a has blade flanks d that are parallel to a central axis c. In a cross-sectional view, the edge b has a cutting wedge with two cutting flanks e located on the flanks of the cutting wedge and angled relative to the central axis c of the blade a by a grinding angle α, as well as a cutting edge f. The edge b, which may have been produced by a grinding process, has a single-bevel grind with two cutting flanks e.With respect to the extended central axis c of the blade a, the opposing cutting flanks e of the cutting edge b are symmetrical and essentially straight. Only in the area of ​​the cutting edge f do the cutting flanks e exhibit a slightly convex shape.

[0047] The Fig. 2 and Fig. Figure 3 represents a first embodiment of the device 1 according to the invention for determining the profile of a cutting edge b in different states. These two figures are therefore described together. Fig. Figure 2 shows the device 1 in a state before the start of a profile determination and Fig. 3 in a state during profile determination. The device 1 comprises a force measuring device 2 and a computing unit 3. The force measuring device 2 is configured to measure a force exerted on the force measuring device 2 by the cutting edge b. The computing unit 3 is configured to receive a measurement signal from the force measuring device 2 and to calculate the profile of the cutting edge b based on the measurement signal. The device is designed such that the force measuring device 2 and the cutting edge b can be moved relative to each other in a direction of movement A for determining the profile of the cutting edge b. The direction of movement A is defined in the Fig. 2 and Fig. 3 shown embodiment is oriented parallel to the orientation of the central axis c of the blade, whose cutting profile is to be determined.

[0048] The force measuring device 2 has two opposing and sectionally separating support elements 4, two force sensors 5, and two mountings 6 that are fixed relative to each other. As an alternative to the version with two mountings 6, the version described in the Fig. 2 and Fig. The device shown in Figure 3 may also only have a holder 6 on which, for example, both system elements 4 are arranged.

[0049] The system elements 4 each have an elongated deflection element 7 and a sensing element 8. The deflection elements 7 and the sensing elements 8 are in Fig. 2 symmetrically designed and arranged relative to each other, with the stylus tips of the stylus elements 8 in the Fig. In the state shown in section 2, the probe tips are in essentially forceless contact with each other before profile determination. Alternatively, and preferably, a small gap between the probe tips can be provided in the state before profile determination.

[0050] The elongated deflection elements 7 are designed as elastically deformable bending elements and each comprises a first end 9 and a second end 10 in a principal extension direction B. The first end 9 is fixed to the support 6 against rotation, and the second end 10 is elastically deflectable. Approximately midway between the first end 9 and the second end 10 in the principal extension direction B, the deflection element 7, designed as a bending element, has a region of cross-sectional reduction 11. Due to this cross-sectional reduction, the area moment of inertia is reduced in this region 11, so that bending of the bending element can occur, particularly in the region of the cross-sectional reduction 11.

[0051] The force sensors 5 can be designed as strain gauges and arranged on the outer side of each of the two deflection elements 7, which are designed as bending elements, in the area of ​​the cross-sectional reduction 11. Since the bending is particularly pronounced in this area, the force sensors 5 are especially sensitive to bending of the deflection elements 7.

[0052] To determine the profile of the cutting edge b, the blade can, for example, be held in a fixed position with the cutting edge b, and the supports 6 can be moved together towards the cutting edge b in the direction of movement A. This brings the deflection elements 7, designed as bending elements, into contact with the cutting edge f of the cutting edge b, and the cutting edge b exerts a force on the contact elements 4 and, in particular, via the sensing elements 8, on the deflection elements 7. The deflection elements 7, designed as bending elements, are pushed apart section by section by the force, whereby, in particular, the areas of the deflection elements 7 encompassing the second end 10 above the area of ​​the cross-sectional reduction 11 are pushed away from the force, and the deflection elements 7 are thus bent. The bending is greatest in the area of ​​the cross-sectional reduction 11.

[0053] If the holders 6 continue to move together in the direction of movement A towards the cutting edge b, the sensing elements 8 are guided along the cutting flanks e with their sensing tips, as shown in particular in Fig. Figure 3 shows that, due to the wedge-shaped cross-section of the cutting edge b, the elastic bending of the deflection elements 7 and thus the force acting on the deflection elements 7 from the cutting flanks e increases when the supports 6 with the deflection elements 7 are moved further towards the cutting edge b in the direction of movement A.

[0054] Due to the bending, particularly in the area of ​​cross-sectional reduction 11 of the deflection elements 7, the force sensors 5, designed, for example, as strain gauges, are compressed or stretched. The compression or stretching correlates with the force acting on the deflection elements 7, which can thus be measured in a simple manner. In particular, the force acting on the force measuring device 2 from the cutting edge b can be measured at predetermined intervals along the direction of movement A.

[0055] The force exerted by the cutting edge b on the force measuring device 2, as measured by the force sensors 5, is transmitted as an electrical measurement signal to the processing unit 3. Transmission can be wireless or wired. In the processing unit 3, the measurement results can be linked and stored with the position of the supports 6, the deflection elements 7, and / or the probe element 8 along the direction of movement A with respect to the cutting edge b and, in particular, with respect to the cutting edge f. Additionally or alternatively, based on the force measurement results, the processing unit 3 can easily calculate a displacement of the probe tips of the probe elements 8 and / or the second ends 10 of the deflection elements 7 in the direction in which the force acts on the force measuring device 2. In particular, the direction in which the force acts on the force measuring device 2 can be oriented orthogonally to the direction of movement A.

[0056] From the measured force, the computing unit 3 calculates the displacement of the probe tips of the probe elements 8 and / or the second ends 10 of the deflection elements 7. The calculation in the computing unit 3 can be based in particular on a calibration, for example in the form of a characteristic curve stored in the computing unit 3 for the displacements corresponding to the measured forces.

[0057] If the force measuring device 2 measures a force acting on the cutting edge b from the cutting edge at a plurality of positions on the cutting flanks e of the cutting edge b, a displacement of the stylus tips of the stylus elements 8 and / or the second ends 10 of the deflection elements 7 can be calculated at each of these positions. Based on the plurality of displacements calculated on the cutting flanks e, it is possible to reconstruct the profile of the cutting edge b and / or to calculate characteristic values ​​describing the profile of the cutting edge b.

[0058] The in the Fig. 4 and Fig. The second embodiment of the device 1 according to the invention, shown in Figure 5, is similar to the one shown in the Fig. 2 and Fig. 3 embodiment shown. In particular, the second embodiment of the device 1 also has the computing unit 3 and the force measuring device 2 with the support elements 4 and the force sensors 5. The support elements 4 further comprise elongated, symmetrical deflection elements 7 and a sensing element 8. The deflection elements 7 are, in comparison to those shown in the Fig. 2 and Fig. The 3 deflection elements shown are designed differently. The following only describes the differences in the Fig. 4 and Fig. 5 embodiment shown in the Fig. 2 and Fig. 3 described the embodiment shown.

[0059] The deflection elements 7 exhibit the following characteristics when viewed in the Fig. 4 and Fig. In the embodiment of the device 1 shown in Figure 5, two adjacent elongated sections 12 and 13 extend along the main direction B, with the first section 12 encompassing the first end 9 and the second section 13 encompassing the second end 10. The first sections 12 each have a higher stiffness than the adjacent second sections 13. The first sections 12 of the device shown in the Fig. 4 and Fig. The deflection elements 7 shown in section 5 can be described in particular as being related to those described in the Fig. 2 and Fig. The 3 deflection elements shown can be considered identical. The second sections 13 are, in comparison with those in the Fig. 2 and Fig. The deflection elements shown in section 3 are an additional component of the deflection elements 7. The higher stiffness of the first sections 12 is due to the Fig. 4 and Fig. 5 is visualized by the fact that the second section 13 is narrower than the first section 12, and in particular also narrower than the cross-sectional reduction area 11 of the first section 12. The higher stiffness of the first section 12 can be achieved, for example, by the first section 12 having a higher area moment of inertia than the second section 13, and / or by the fact that the modulus of elasticity of the material from which the first section 12 is formed is greater than the modulus of elasticity of the material from which the second section 13 is formed. The first sections 12 of the in the Fig. 4 and Fig. The deflection elements 7 shown in Figure 5 can, for example, be commercially available load cells. A combination of a commercially available load cell in the form of the first section 12 with a less rigid second section 13, which is more easily deflected upon contact with the cutting edge b than the commercially available load cell, allows for a cost-effective and simple determination of the profile of the cutting edge b without scratching it. As shown in particular in Fig. As shown in Figure 5, the bending of the second section 13 during the determination of the cutting edge profile b is greater than the bending of the first section 12, on which the force sensor 5 is located. Even with a small bending of the first section, a comparatively large displacement of the stylus tips of the stylus elements 8 and / or the second ends 10 of the deflection elements 7 can thus be easily calculated by the computing unit 3.

[0060] Furthermore, the profile of the cutting edge b is determined using the one described in the Fig. 4 and Fig. 5 second embodiment of the device 1 analogous to determining the cutting edge b with the in the Fig. 2 and Fig. 3 first embodiment of the device shown.

[0061] The in the Fig. The third embodiment of the device 1 according to the invention, shown in Figures 6 to 11, is based on the embodiment shown in the Fig. 4 and Fig. 5 embodiment of the device 1. In comparison with the one shown in the Fig. 4 and Fig. The embodiment shown in section 5 is the one described in the Fig. The third embodiment shown in 6 to 11 represents a further development. Fig. Sections 6 to 11 are discussed below jointly and in particular with reference to the description of the Fig. 1 to 5 described.

[0062] The in the Fig. The third embodiment of device 1 shown in Figures 6 to 11 also includes the computing unit (in the Fig. 6 to 11 not recognizable) and deflection elements 7 with force sensors not shown in the drawing.

[0063] In the third embodiment, at least some of the functional components of the device 1 described here are arranged at least partially within a housing 14. A means for the optical output of information 15 in the form of a display is arranged on a front face of the housing 14. The results of determining a profile of the cutting edge b can be displayed on the display 15. In particular, the display 15 can be used to show an enlarged graphical reconstruction of the determined profile based on the calculation of the profile of the cutting edge b.

[0064] As particularly in Fig. As can be seen from 11, the following are included in the Fig. The housing 14, which is essentially concealed from the housing 14, comprises elongated, symmetrical deflection elements 7 and a sensing element 8. The deflection elements 7 have two adjacent, elongated sections 12 and 13 in the main extension direction B, with the first section 12 encompassing the first end 9 and the second section 13 encompassing the second end 10. The first sections 12 each have a higher stiffness than the adjacent second sections 13. The first sections 12 are formed, in particular, from commercially available load cells. The second sections 13 are structurally connected to the first sections 12 formed from the load cells by a detachable connection.Due to the detachable connection, the second sections 13 are interchangeable, so that different second sections 13 with, for example, different strengths, geometries and / or materials can be selectively chosen for different blades or knives.

[0065] The sensing elements 8 are held at the second ends 10 of the second sections 13, in a particularly interchangeable manner, and can be designed to be slidable. For example, the sensing elements 8 can be received in the second sections 13 by means of a friction-fit connection, in particular a screw (not shown) that presses the sensing elements against the second sections 13. Due to the releasable friction-fit connection, the position of the sensing elements relative to the second sections 13 can be flexibly adjusted and thus adapted to different cutting edge thicknesses. The sensing elements can also be replaced.

[0066] The first sections 12 of the deflection elements 7 are both rotationally fixed to a common support 6. The support 6 and the deflection elements 7 rigidly connected to it can be displaced along guide elements 16. The guide elements 16 can, in particular, have an elongated shape and a constant cross-section. The principal extension direction of the in Fig. The guide elements shown in Figure 11, designed as cylinders, are parallel to the main extension direction B of the deflection elements 7 shown in the figure and are identical to the direction of movement A in which the deflection elements 7 are movable.

[0067] In order to enable relative movement between the cutting edge b and the deflection elements 7, the embodiment of the device 1 described here has a drive unit 17, which may be equipped with a displacement sensor 20. Furthermore, the device 1 has two holding devices 18 and support elements 19 for positioning the knife.

[0068] The drive unit 17 is designed to move the holder 6 and the deflection elements 7 rigidly connected to it in relation to the cutting edge along the direction of movement A. In the Fig. In the embodiment of the device 1 shown in Figures 6 to 11, the drive unit 17 comprises a handwheel, a threaded rod 24 arranged parallel to the guide elements 16 and fixedly connected to the handwheel, and a runner with an internal thread that is movable along the threaded rod 24. The runner is fixedly connected to the holder 6. When the handwheel is turned, the runner, the holder 6, and the deflection elements 7 are moved towards or away from the cutting edge b in the direction of movement A. The housing 14 is designed, in particular, so that an operator of the device 1 can grip the housing 14 with one hand. The movement can be generated manually using the handwheel. This is particularly advantageous when the housing 14 is designed so that an operator of the device 1 can grip it with one hand. Alternatively, a motor drive can be provided to perform the movement.

[0069] Each of the holding devices 18 is designed to hold the blade with its cutting edge b. The holding devices 18 each have a rubber-coated magnet 21. The magnet 21 is flush with a flat holding surface of a receiving element 22 of the holding devices 18. The receiving elements 22 are each structurally connected to an adjusting device 23 of the holding devices 18, by means of which the receiving elements 22, the magnets 21, and the blade held by the holding device 18 can be arranged in an adjustable position along an adjustment direction C. In the embodiment of the device 1 described here, the adjustment direction C is oriented orthogonally to the direction of movement A.

[0070] For positioning along the adjustment direction C, each of the adjusting devices 23 has a drive in the form of an adjusting screw. When the adjusting screws are turned, the receiving elements 22, the magnets 21, and the blade held by the holding device 18 are moved in the adjustment direction C. The adjusting device 23 can further comprise two ball joints (in the Fig. 6 to 11 not shown), with which the receiving elements 22 and thus a blade arranged thereon can be balanced.

[0071] The support elements 19 ensure that the blade is held in a fixed position. They serve as a support for the cutting edge f of a blade whose cutting profile is to be determined. For this purpose, two support elements 19 are arranged below the holding devices 18 and centrally between the symmetrical deflection elements 7 along a virtual straight line. The support elements 19 have a section coated with a rubber layer on which the cutting edge f of the blade can be supported for determining the profile of the cutting edge b. Due to the holding devices 18 and the support elements 19, a blade can be held in a particularly secure position, so that displacement of the cutting edge b during movement of the support elements 7 along the cutting flanks e can be largely avoided.

[0072] To measure the movement of the deflection elements 7 in the direction of movement A, the device 1 has the displacement sensor 20. As an implementation example for the displacement sensor, it is particularly evident in the Fig. Figure 11 shows a rotary encoder. The rotary encoder can, for example, detect the angle of rotation of the threaded rod of the drive device 17 and transmit this angle of rotation to the processing unit 3. In the processing unit 3, a movement of the deflection elements 7 and / or a displacement of the deflection elements 7 by a distance dependent on the angle of rotation in the direction of movement A can be calculated from the angle of rotation.

[0073] In the processing unit 3, measurement results obtained with the force measuring device 2 and measurement results obtained with the optional displacement sensor 20 can be combined. This allows the profile of a cutting edge b, examined with the device, to be calculated automatically and easily. The displacement sensor is particularly advantageous if the cutting edge flank e is not a flat surface but is profiled or consists of several surfaces, and these profiles or surface sections are to be represented. If, in the case of flat cutting edge flanks e, the device 1 is only intended to determine the angle α, this can be obtained from the sensor signal even without a displacement measurement. Optionally, the device 1 can include a storage unit (not shown here) on which the measurement results and / or a determined profile of a cutting edge b are stored.Optionally, the device 1 can also include a unit that compares the measured profile with a predetermined target profile and determines deviations of the measured profile from the target profile.

[0074] The features of the invention disclosed in this description, in the drawings, and in the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention is not limited to the described embodiments. It can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. Reference symbol list 1 Device 2 Force measuring device 3 Computing Unit 4 Plant element 5 Force sensor 6 brackets 7 Deflection element 8 Key element 9 first end 10 second end 11 Area of ​​cross-sectional reduction 12 first section 13 second section 14 cases 15 Means for the optical output of information, display 16 guide element 17 Drive unit 18 Holding device 19 Support element 20 displacement sensor 21 magnets 22 Recording element 23 Actuator 24 threaded rod A direction of movement B Main extension direction of the deflection element C Adjustment direction a blade b cutting c Central axis of the blade d blade flanks e cutting edges f cutting edge α Grinding angle

Claims

[1] Device (1) for determining a profile of a cutting edge (b), comprising a force measuring device (2) and a computing unit (3), wherein the force measuring device (2) is configured to measure a force exerted by the cutting edge (b) on the force measuring device (2), wherein the computing unit (3) is configured to receive a measurement signal from the force measuring device (2) and to calculate the profile of the cutting edge (b) and / or at least a characteristic value describing the profile of the cutting edge (b) on the basis of the measurement signal. [2] Device according to claim 1, characterized bythat the device (1) has a drive unit (17), wherein the drive unit (17) is configured to move the cutting edge (b), the profile of which is to be determined, in relation to the force measuring device (2) along a direction of movement (A), or the drive unit (17) is configured to move at least one component of the force measuring device (2) in relation to the cutting edge (b) along the direction of movement (A). [3] Device according to one of claims 1 or 2, characterized by , that the device (1) has a displacement sensor (20), wherein the displacement sensor (20) is configured to measure a distance of a relative movement between the cutting edge (b) and at least one component of the force measuring device (2) along a direction of movement (A). [4] Device according to one of the preceding claims, characterized by, that the force measuring device (2) has two opposing system elements (4) that can be pushed apart at least in sections. [5] Device according to claim 4, characterized by , that at least one of the system elements (4) has an elongated deflection element (7) with a first end (9) and a second end (10) in a principal extension direction (B), wherein the first end (9) is supported on a bracket (6), wherein the second end (10) is deflectable. [6] Device according to claim 5, characterized by , that both system elements (4) have the deflection element (7), in particular wherein the two deflection elements (7) are designed and / or arranged symmetrically to each other. [7] Device according to claim 5 or 6, characterized by , that the at least one deflection element (7) is an elastically deformable bending element, wherein the first end (9) is fixed to the support (6) in a rotationally fixed manner. [8] Device according to claim 5 or 6, characterized by , that the at least one deflection element (7) is a rigid deflection element (7) wherein the first end (9) is rotatably mounted on the support (6). [9] Device according to claim 7, characterized by , that the force measuring device (2) has a force sensor (5) which is designed as a strain gauge arranged on the bending element (7). [10] Device according to any one of claims 5 to 9, characterized by , that the at least one deflection element (7) in the principal extension direction (B) has two elongated sections (12, 13), wherein the first section (12) includes the first end (9) and the second section (13) includes the second end (10), wherein the first section (12) is stiffer than the second section (13). [11] Device according to any of the preceding claims, characterized bythat the device (1) has at least one holding device (18), wherein the at least one holding device (18) is designed to hold a blade with the cutting edge (b) whose profile is to be determined, in particular wherein at least one holding device (18) has at least one magnet (21). [12] Device according to the preceding claim, characterized by , that the at least one holding device (18) has an adjusting device (23), wherein the adjusting device (23) is configured to arrange a blade held by the holding device (18) with the cutting edge (b), the profile of which is to be determined, in an adjustable position along an adjustment direction (C). [13] Method for determining a profile of a cutting edge (b) comprising the following steps: • Providing a device (1) according to one of the preceding claims; • Arrange a blade with the cutting edge (b) whose profile is to be determined on the force measuring device (2); • Moving the force measuring device (2) and / or the blade with the cutting edge (b) in relation to each other and thereby exerting a force with the cutting edge (b) on the force measuring device (2); • Measuring the force exerted by the cutting edge (b) on the force measuring device (2) using the force measuring device (2); • Transmitting the measurement signal from the force measuring device (2) to the computing unit (3) and calculating the profile of the cutting edge (b) and / or at least one characteristic value describing the profile of the cutting edge (b) based on the measurement signal. [14] Procedure according to the preceding claim, characterized by, that the device (1) has two opposing support elements (4), wherein the blade with the cutting edge (b) is arranged on the support elements (4) such that these support elements (4) are pushed apart at least section by a relative movement of the cutting edge (b) and / or at least one of the support elements (4) relative to each other. [15] Method according to claim 13 or 14, characterized by , that the calculation of the profile of the cutting edge (b) and / or at least one characteristic value describing the profile of the cutting edge (b) in the computing unit (3) is based on a calibration which is based on the measurement of at least one physical embodiment with the device (1).

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