JP7549578B2 - MEASURING ROLL FOR DETERMINING A CHARACTERISTIC OF A STRIP-LIKE ARTICLE THAT IS GUIDED THROUGH THE MEASURING ROLL - Patent application - Google Patents

Description

The present invention relates to a measuring roll for detecting the properties of a strip-shaped article, in particular a metal strip, guided through the measuring roll. The present invention further relates to a method for detecting the properties of a strip-shaped article, in particular a metal strip, guided through the measuring roll. The present invention also relates to the use of such a measuring roll.

Measuring rolls are used during the cold and hot rolling of metal strips and are known, for example, from DE 42 36 657 A1.

For conventional measurement of the flatness during rolling of a strip, essentially a method is used in which the strip is guided at a defined wrap angle through a measuring roll equipped with a force sensor.

In this way, in the measuring roll according to DE 42 36 657 A1, contact is made between the force encoder or its cover, which is arranged in a radial recess of the measuring roll that is open towards the measuring roll surface, and the strip. There is a cylindrical gap between the force sensor, which is clamped to the bottom of the recess, and the recess wall surrounding the force sensor. To prevent contaminants, such as strip wear debris and lubricant, from entering the ring gap between the force sensor and the measuring roll body, this gap can be closed by sealing the shoulder with an O-ring or by sealing the front with a plastic layer. As shown in FIG. 1c of DE 42 36 657 A1, the encoder can also be arranged in a recess of the solid roll and then covered by a machined diaphragm.

The arrangement of the force sensor at a distance from the wall surrounding it and the closure of the ring gap with an O-ring or a sufficiently elastic plastic (DE 196 16 980 A1) prevents lateral forces occurring in the body of the measuring roll during rolling from acting as disturbances on the force sensor or the measurement result. Such disturbance forces arise as a result of the strip tension acting on the measuring roll and the associated deflection of the measuring roll. In this case, the cross section of the measuring roll takes the shape of an ellipse whose major axis runs parallel to the strip. If the deflection of the measuring roll is transmitted to the encoder by force branching, it is misinterpreted by the force sensor as an unevenness of the strip. When using sealing elements in the ring gap, such force branching cannot be completely avoided, since the sealing force necessarily acts on the force sensor.

From DE 102 07 501 C2 a solid roll for detecting flatness deviations during the processing of strip-shaped articles, in particular metal strips, is known, which has a force sensor arranged in a recess, which is accessible in the axial direction. The formation of the axially extending recesses is often carried out by means of a deep hole drilling tool. For measuring rolls with a roll width of more than 1000 mm, very long drilling tools must be used, since for drilling from the end side of the recess the drilling tool must first be passed over the partly very long journal. This is often due to the length of the drilling passage.

From German Utility Model 202007001066, a measuring roll for detecting flatness deviations during processing of strip-shaped articles, in particular metal strips, is known, which has a measuring roll body, a cover tube that at least partially surrounds the measuring roll body, and a force sensor arranged in a recess, the recess extending from one end face of the measuring roll into the measuring roll body and/or into the cover tube. The recess can be closed at the end face side by a cover. The journals on each end face of the measuring roll are molded into the measuring roll body. A disadvantage of this measuring roll is that the provision of the recesses makes the measuring roll body or the cover tube weak. With wide measuring rolls, the passage of the bearing journals, as in the case of deep hole processing, is also a major disadvantage. Another problem is that the passages/grooves are produced by a milling tool (polygonal passages) and not by a drilling tool (circular passages), as in DE 102 07 501, which results in wear of the passages/grooves that are provided up to the end faces.

Prior art measuring rolls determine the flatness of the strip by means of individual sensors distributed over the circumference of the measuring roll. In this case, the measurement results of the individual sensors are often correlated during evaluation to determine the flatness. With prior art measuring rolls, measurement errors occur whenever the metal strip vibrates. This is the case, for example, when the measuring roll is arranged close to the reel. Due to the vibrations, the force values acting on the individual force sensors no longer depend only on the strip tension and the flatness of the strip, but are increased or decreased by the vibrations. This indeed leads to measurement errors in evaluation methods in which the measurement results of the individual sensors distributed over the circumference are compared with each other.

The problem underlying the present invention is to increase the information value of the inspection carried out by such a measuring roll of the properties of a strip of an article guided through the measuring roll.

This problem is solved by the subject matter of claims 1, 8 and 9. Preferred embodiments are described in the dependent claims and are explained in more detail in the following description.

The invention proceeds from the basic idea of arranging a first force sensor laterally of a second force sensor in one recess of the measuring roll body of the measuring roll, the two force sensors being arranged so close to each other that the sensor surface of the first force sensor is directly adjacent to the sensor surface of the second force sensor, or the first force sensor has an end boundary line extending in the radial direction of the measuring roll and intersecting with a point of the sensor surface of the first force sensor which is closest to the sensor surface of the second force sensor,
- extending in a plane including a line connecting a point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and a point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor and an end boundary line, and - intersecting the end boundary line at an intersection of the end boundary line with the circumferential surface, and - being located adjacent to the second force sensor so that the angle between the line intersecting the point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor is less than 65°. Alternatively, the invention proceeds from the basic idea of arranging a first force sensor in a first recess of the measuring roll body of the measuring roll and a second force sensor in a second recess adjacent to the first recess, both force sensors being arranged in a plane including a line connecting a point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and an end boundary line that extends in the radial direction of the measuring roll and intersecting a point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor, and
- extend in a plane including the end boundary line and a line connecting a point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and a point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor; and - intersect the end boundary line at an intersection of the end boundary line and the circumferential surface; and - are arranged adjacent to each other such that the angle between the line intersecting the point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor is less than 65°.

It is known from the prior art to arrange several force sensors in a recess of the measuring roll body. In paragraph 3, lines 1-2, of DE 10207501 A1, it is taught to arrange several force sensors in a recess at a distance from one another. FIG. 2 of US 2013/0298625 A1 also shows several force sensors arranged at a distance from one another. In paragraph [0021] of DE 102014012426 A1, it is taught to arrange several force sensors in a recess, which is embodied in FIG. 2 of this specification by the arrangement of several force sensors in this recess at a distance from one another. From the prior art, it is possible to read the general teaching that in the case of several force sensors arranged in a recess, the force sensors are obviously arranged at a distance from one another. The underlying principle is to distribute the (few) force sensors as widely as possible in the respective recesses, so that the measurements are carried out as widely as possible over the width of the possible measurement area, which is determined by the length of the recesses. Moreover, the widely spaced arrangement of the force sensors in the recesses is probably based on the idea of avoiding erroneous measurements. When measuring the radial force acting on the measuring roll body of the measuring roll by a force sensor arranged in a recess of the measuring roll body at a distance from the circumferential surface of the measuring roll body, there is the problem that the radial force is scattered by the material of the measuring roll body through which it must pass to reach the sensor surface of the force sensor. This phenomenon is called a stress cone or "Roetscherkegel". This effect makes the arrangement of several force sensors in a recess, which are widely spaced from each other, advantageous. In this way, two force sensors arranged next to each other deliver a measurement signal resulting from only one radial force acting on one point on the circumferential surface of the measuring roll body during the flatness measurement, which makes it possible to avoid the necessity of actually measuring with only one of the two sensors for some evaluation methods of the prior art.

According to the invention, it is now possible to provide a method for measuring the flatness of a strip-shaped article, in particular a metal strip, as well as for detecting other properties of a strip-shaped article guided through a measuring roll, in which a first force sensor in the recess is arranged adjacent to the second force sensor so close that the sensor surface of the first force sensor is directly adjacent to the sensor surface of the second force sensor, or an end boundary line extending in the radial direction of the measuring roll and intersecting with a point of the sensor surface of the first force sensor which is closest to the sensor surface of the second force sensor,
It has been recognized that an advantage can be achieved if the force sensor is disposed adjacent to the second force sensor such that: - it extends in a plane including the end boundary line and a line connecting the point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and the point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor; and - it intersects the end boundary line at an intersection of the end boundary line and the circumferential surface; and - the angle between the line intersecting the point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor is close to being less than 65°.

According to the invention, it is possible to arrange as many force sensors as possible in a line. This makes it possible to reduce the number of measurement points along the circumference of the measuring roll. In a further preferred embodiment, it is conceivable to arrange all force sensors required for detecting a characteristic, for example flatness, in a single axially extending recess or in a single row of radially extending adjacent holes. This concentrated arrangement of the individual sensors in a line reduces the influence of vibrations on the measurement result. All sensors arranged in this way see the strip-shaped article in the same vibration state, so that relative information can be obtained more accurately. This increases the information value of the inspection of the characteristics of the strip-shaped article guided through the measuring roll, which is carried out by such a measuring roll. For the measurement of flatness, the arrangement of the force sensors according to the invention can provide the advantage of a higher resolution and a more accurate imaging of the actual flatness.

The measuring roll according to the invention has a measuring roll body. The measuring roll body preferably has a closed circumferential surface. In a preferred embodiment, the measuring roll body is a solid roll extending along the longitudinal axis. A solid roll means a measuring roll body which is integral and whose shape is produced by a one-piece forming process, for example by casting, and/or whose geometric shape is produced from an integral semi-finished product by a separate process, in particular by machining, in particular by turning, drilling, milling or grinding. In a preferred embodiment, in such a measuring roll body formed as a solid roll, the measuring roll journals arranged on the respective end faces of the measuring roll are also part of the integral body, for example for the purpose of rotatably supporting the measuring roll in ball bearings. However, configurations are also conceivable in which the main part of the measuring roll body is formed as a cylindrical solid roll, which has a cover arranged on its end face, on which the measuring roll journals are formed, as shown, for example, in FIG. 2 of DE 202014006820. Furthermore, the measuring roll body according to the invention can be formed, for example, like the measuring roll body described in FIG. 3 of DE 202014006820, in which case an integral journal is formed on the measuring roll body and a cover tube is placed on the measuring roll body. However, in a particularly preferred embodiment, the measuring roll does not have a cover tube and is formed as a solid roll. An embodiment is also conceivable in which the measuring roll body according to the invention is formed from separate plates arranged next to one another, as shown, for example, in DE 2630410.

The measuring roll body of the measuring roll according to the invention preferably has a closed circumferential surface. A closed circumferential surface can be obtained, for example, by forming the measuring roll body as a solid roll and forming all recesses provided in the measuring roll body in such a way that none of the recesses leads from the recesses to the circumferential surface. In such an embodiment, the recesses are particularly preferably guided in the axial direction and have an opening at the end face of the measuring roll body or a transverse passage is provided inside the measuring roll body, which leads from the recesses in the radial direction further into the interior of the measuring roll body, for example to a collecting passage in the center of the measuring roll body. A closed circumferential surface of the measuring roll body can also be obtained in an embodiment in which each recess has a recess leading in the direction towards the circumferential surface, in that these recesses are closed by a closing element. Such a closing element can be, for example, a cover tube, as shown in figures 3 and 4 of DE 10 2014 012 426 A1, which completely surrounds the base body of the measuring roll body. However, the closing element can also be formed in the form of a cover as shown in DE 197 47 655 A1. In a preferred embodiment, however, the measuring roll does not have a cover tube, but is formed as a solid roll, with none of the recesses leading to the periphery, or each recess leading to the periphery but closed by a closing element, for example a cover. It is also conceivable to cover the periphery of the solid roll or the periphery of the cover tube, for example to reduce friction or to protect the strip-shaped article to be guided through the measuring roll.

The measuring roll body of the measuring roll according to the invention is provided with at least one recess. It has been shown that the advantages of the invention can already be obtained with a single recess provided in the measuring roll body. It is therefore conceivable that during flatness measurement, information about the flatness of a strip-shaped article guided through the measuring roll is provided once per revolution of the measuring roll.

In a preferred embodiment, the measuring roll body has a plurality of recesses. In a preferred embodiment, the recesses are formed at the same radial intervals relative to the longitudinal axis of the measuring roll body. In a preferred embodiment, all recesses are distributed equidistantly from one another in the circumferential direction. However, particularly preferred is a first group of recesses that are distributed equidistantly in the circumferential direction at the same radial intervals relative to the longitudinal axis, and in addition to the first group of recesses, at least one further recess is additionally provided, which is formed such that the radial interval relative to the longitudinal axis is different from that of the first group of recesses and/or does not have the equal interval in the circumferential direction that the other recesses have relative to one another. Thus, for example, for flatness measurements, it is conceivable to configure the measuring roll like a prior art measuring roll, for example as a solid roll known from DE 102 07 501 A1 or as a measuring roll known from DE 102 014 012 426 A1, but in this case, for the configuration according to the invention, such a prior art measuring roll can be provided with further recesses, configured outside the pattern, in which further measurements are performed, for example. Preferably, the recesses mentioned in this paragraph are recesses extending in the axial direction of the measuring roll body. Also conceivable is an embodiment in which the measuring roll has only one recess and all force sensors of the measuring roll are arranged in only one recess, for example in only one axially extending recess.

In a preferred embodiment, the measuring roll body has a closed circumferential surface and is closed at the end sides by end faces. In a preferred embodiment, the end faces are arranged at an angle of approximately 90° to the circumferential surface.

In a preferred embodiment, the measurement roll has a bearing journal. In a preferred embodiment, the bearing journal is formed at the end face in the embodiment of the measurement roll having an end face.

In a preferred embodiment, the measuring roll body is cylindrical.

In a first aspect of the invention, the measuring roll according to the invention is formed with at least one recess in the measuring roll body, which recess is arranged at a distance from the circumferential surface, and this recess is not open towards the circumferential surface or further recesses, e.g. holes, leading from the recess to the circumferential surface. In a second aspect of the invention, the recess leads from the circumferential surface into the interior of the measuring roll body, but is closed by a closing element. In a preferred embodiment, the measuring roll is formed with a plurality of recesses in the measuring roll body, which recesses are arranged at a distance from the circumferential surface, and all recesses are formed such that the recesses, e.g. holes, do not lead from the recess to the circumferential surface (and the recesses themselves do not open to the circumferential surface), or some recesses are formed such that no recess leads from the respective recess to the circumferential surface, and in other recesses there are recesses leading in the direction towards the circumferential surface, but these recesses are closed by a closing element. The closing element is, as described above, a cover or, for example, a cover tube.

In a preferred embodiment, one recess of the measuring roll body extends in a direction parallel to the longitudinal axis of the measuring roll body. According to a preferred embodiment, if the measuring roll body is provided with several recesses, it is preferred that all recesses of the measuring roll body each extend in a direction parallel to the longitudinal axis of the measuring roll body. In a preferred embodiment, each recess is open at least at one end, preferably at both ends, at the end face of the measuring roll body. The recess terminating at one end face of the measuring roll body can be closed by an end cap, which closes only this recess. Also conceivable is an embodiment in which the end face of the measuring roll body is entirely closed by a cover, as shown, for example, in Figs. 1 and 2 or 4 of DE 10 2014 012 426 A1.

In a preferred embodiment, the recess is elongated, where "elongated" means that the recess is larger in a first direction (the longitudinal direction of the recess) than in a direction extending approximately perpendicular to this direction. In a preferred embodiment, the extension of the elongated recess in the longitudinal direction is twice as large, or more preferably more than twice as large, than in a direction extending approximately perpendicular to this direction. In a preferred embodiment, the longitudinal direction of the recess forms an angle with the longitudinal direction of the measuring roll body of less than 75°, particularly preferably less than 45°, particularly preferably less than 30°, particularly preferably less than 10°, particularly preferably less than 5°. In a preferred embodiment, the longitudinal direction of the recess does not extend perpendicular to the longitudinal axis of the measuring roll body. If, as is conceivable in one embodiment, the longitudinal axis of the recess does not intersect with the longitudinal axis of the measuring roll body, the design provisions as described above apply to the projection of the longitudinal axis of the recess onto a plane containing the longitudinal axis of the measuring roll body. In such an embodiment, the projection of the longitudinal axis of the recess onto a plane containing the longitudinal axis of the measuring roll body is therefore formed such that the longitudinal projection of the recess forms an angle with the longitudinal direction of the measuring roll body of less than 75°, particularly preferably less than 45°, particularly preferably less than 30°, particularly preferably less than 10°, particularly preferably less than 5°. In a preferred embodiment in which the recess extends parallel to the longitudinal axis of the measuring roll body, the longitudinal axis of the recess clearly does not intersect the longitudinal axis of the measuring roll body, and similarly the projection of the longitudinal axis onto a plane containing the longitudinal axis of the measuring roll body hardly intersects the longitudinal axis of the measuring roll body. German Utility Model No. 202007001066 shows, for example, a measuring roll with an elongated recess.

In another preferred embodiment, the recesses are not elongated but are formed as radially extending pockets, as for example in DE 198 38 457 A1. In such an embodiment, the radially extending recesses can be dimensioned in their cross section such that, for example, they can accommodate two force sensors if they have the shape of the number 8. Alternatively, in this embodiment, one force sensor can be provided per recess, but in this case the recesses have an end boundary line that extends in the radial direction of the measuring roll and intersects with a point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor, and
- extend in a plane including the end boundary line and a line connecting the point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and the point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor; and - intersect the end boundary line at an intersection of the end boundary line and the circumferential surface; and - are arranged adjacent to each other such that the angle between the line intersecting the point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor is less than 65°.

In a preferred embodiment, a first and a second force sensor are arranged in one recess of the measuring roll (in the case where the measuring roll has only one recess). The first force sensor has a sensor surface, which can generate a sensor signal if the position of the sensor surface of the first force sensor changes. The second force sensor also has a sensor surface, which can generate a sensor signal if the position of the sensor surface of the second force sensor changes. The force sensor is called a force sensor because it is used to measure a force, particularly preferably a pressing force. To measure the force acting on the force sensor, the force sensor has a sensor surface and is designed in such a way that it can generate a sensor signal if the position of the sensor surface changes. The force sensor often has an associated reference system and reacts to a change in the position of the sensor surface in this reference system. The force sensor often has a casing. In this case, the reference system is often the casing. In such an embodiment, the force sensor can detect, for example, whether the position of the sensor surface has changed relative to the casing. If the force sensor is designed as a piezoelectric force sensor, for example, it has a piezoelectric quartz, which can generate an electrical signal when the position of the surface of the piezoelectric quartz changes relative to a reference surface, for example relative to the opposing surface of the piezoelectric quartz, for example when the piezoelectric quartz is compressed. In a force sensor designed as a strain gauge, the change in position of the surface of the force sensor changes the length of the measuring wire or of the measuring grid formed from the measuring wire, which is mainly stretched, but also partially crushed. In a force sensor designed as an optical force sensor, the optical properties of the force sensor, for example the refractive index or reflection properties, change with the change in position of the surface.

The force sensor mounted according to the invention has a sensor surface, the positional changes of which are monitored in order to determine the force acting on the force sensor. An embodiment is conceivable in which the sensor surface is the surface of an element whose properties change in order to generate a sensor signal, for example the surface of the piezoelectric quartz itself. However, in many cases, in force sensors of this type, an intermediate member is provided on which the sensor surface is formed. In many cases, intermediate members of this type are rigid blocks, in which a change in the position of one surface of the rigid block directly leads to a change in the position of the opposite surface due to the rigidity of the block. Intermediate members of this type can be used to form the sensor surface protruding from the rest of the force sensor, in particular from the casing. A sensor surface protruding from the rest of the force sensor forms a clearly defined surface on which the environment can act, which increases the measurement accuracy. A protruding sensor surface can, for example, avoid measurement errors due to branching of forces. The force sensor according to the invention can be formed, for example, like the force sensor shown in DE 1773551 A1 and can have a piezoelectric element consisting of a multi-layer crystal assembly arranged between two force transmission plates arranged in a casing. In such an embodiment, the sensor surface is the outer surface of the upper force transmission plate in FIG. 1 of DE 1773551 A1 or the outer surface of the lower force transmission plate in FIG. 1 of DE 1773551 A1.

In a preferred embodiment, the sensor surface is formed flat. In a preferred embodiment, the surface normal of the flat sensor surface of the first force sensor is directed toward the circumferential surface. The surface normal of the sensor surface of the second force sensor is also formed flat in a preferred embodiment and is also directed toward the circumferential surface in a preferred embodiment. In a preferred embodiment, the surface normal of the sensor surface of the first force sensor is parallel to the surface normal of the sensor surface of the second force sensor. In a preferred embodiment, the radial direction of the measuring roll body is the surface normal of the sensor surface of the first force sensor and/or the second force sensor.

In a preferred embodiment, the surface normal of the flat sensor surface, at the point of the sensor surface where the sensor surface intersects with a radial line of the measuring roll body, forms an angle of less than 45°, particularly preferably less than 20°, particularly preferably less than 10°, particularly preferably less than 5° with respect to this radial line of the measuring roll body.

In a preferred embodiment, the sensor surfaces of the force sensors used in the measuring roll according to the present invention, in particular the first force sensor and/or the second force sensor, are flat surfaces.

In a preferred embodiment, the sensor surface of the first force sensor is formed symmetrically with respect to a plane that includes the longitudinal axis of the measuring roll body, intersects the sensor surface of the force sensor, and in which the surface normal of the sensor surface is also located.

In a preferred embodiment, the sensor surface is ring-shaped, in particular annular. Also preferred are embodiments in which the sensor surface is circular or elliptical. Rectangular, square or polygonal sensor surfaces are also conceivable. In a preferred embodiment, the sensor surface is flat.

In a preferred embodiment, the sensor surface is a surface that protrudes from the other elements of the force sensor and is in contact with a boundary surface of the recess or with a closing surface that closes the recess against the surrounding surface.

In a preferred embodiment, at least two force sensors used in the measuring roll according to the invention, particularly preferably some of the force sensors used in the measuring roll according to the invention, particularly preferably all the force sensors used in the measuring roll according to the invention, are configured similarly and therefore in the same way, in particular of the same type, particularly preferably identically.

According to a first variant of the measuring roll according to the invention, the first force sensor is arranged in the recess adjacent to the second force sensor. This means that the sensor surface of the first force sensor is arranged closer to the end face of the measuring roll body than the sensor surface of the second force sensor. It is conceivable that the first force sensor is arranged in the recess offset in the circumferential direction with respect to the second force sensor. However, in a preferred embodiment, the first and second force sensors are arranged without being offset from each other in the circumferential direction.

In a preferred embodiment, the first force sensor and the second force sensor are arranged at the same radial distance from the longitudinal axis of the measuring roll body.

In the measuring roll according to the invention, the sensor surface of the first force sensor is directly adjacent to the sensor surface of the second force sensor, or the first force sensor extends in the radial direction of the measuring roll and has an end boundary line that intersects with a point of the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor;
- extends in a plane including a line connecting a point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and a point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor and the end boundary line, and - intersects the end boundary line at an intersection of the end boundary line and the circumferential surface, and - is positioned adjacent to the second force sensor such that the angle between the line intersecting the point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor is less than 65°.

Of the two alternative embodiments according to the invention described above, the embodiment in which the sensor surface of the first force sensor is directly adjacent to the sensor surface of the second force sensor is particularly preferred. Thus, for example, in the case of a circular or toric sensor surface, a point located on the circumference of the first sensor surface, which is circularly or toric, is adjacent to a point located on the circumference of the second sensor surface, which is circularly or toric. In such an embodiment of the invention, the radial forces acting on the circumference of the measuring roll can be completely measured. However, such an arrangement leads to a branching of forces, and it is expected that the movement of the first sensor surface due to the forces acting on the first sensor surface will move the second sensor surface, for example, due to friction at the periphery of the sensor surface. Branching of forces can only be prevented if the periphery of the sensor surface is so smoothly designed that it does not transmit frictional forces. In the practically relevant implementation, therefore, it is mainly assumed that the sensor surfaces are spaced slightly apart from each other, so that the measurement result of each sensor surface is not influenced by the load of the adjacent sensor surface.

In another alternative aspect according to the invention, the sensor faces are spaced apart from one another, but extend in the radial direction of the measuring roll and intersect with a point on the sensor face of the first force sensor that is closest to the sensor face of the second force sensor, and
- extend in a plane including the end boundary line and a line connecting the point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and the point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor; and - intersect the end boundary line at an intersection of the end boundary line and the circumferential surface; and - are positioned close enough to each other that the angle between the line intersecting the point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor is less than 65°.

The claimed design provisions according to the invention are based on radially extending edge boundaries. In practical use, measuring rolls are usually used for measuring radially acting forces. Such forces arise when the strip-shaped article to be inspected is partially wrapped around the measuring roll. The edge boundary defines the point at which the radially acting force is still directly above the sensor surface of one of the force sensors by the point at which the edge boundary crosses the circumferential surface, but only above the points located around the sensor surface, whether the sensor surface is circularly or annularly formed.

Given such edge boundaries, the present invention defines the spacing for adjacent sensor faces as:
- extends in a plane including a line connecting a point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and a point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor, and the end boundary line; - intersects the end boundary line at an intersection of the end boundary line and the circumferential surface; and - is defined via the angular position of a line intersecting a point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor.

According to the invention, the angle between these lines is less than 65°, particularly preferably less than 55°, particularly preferably 45° or less, particularly preferably 40° or less, particularly preferably 35° or less, particularly preferably 30° or less, particularly preferably 20° or less, particularly preferably 10° or less, particularly preferably 5° or less.

Thus, according to the invention, there is also provided an embodiment in which a portion of the second sensor surface is inside a "Roetscherkegel" originating from a radially acting force acting on the circumferential surface at the intersection of the end boundary line and the circumferential surface.

In a preferred embodiment, the line connecting the point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and the point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor extends parallel to the longitudinal axis of the measuring roll. This is in particular the case when the first and second force sensors are arranged in an elongated recess, the direction of longitudinal extension of which extends parallel to the longitudinal axis of the measuring roll. However, embodiments are also conceivable in which the first force sensor is arranged in a first radial recess, preferably in a pocket, and the second force sensor is arranged in a second radial recess, preferably in a pocket. In such an embodiment, the line connecting the point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and the point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor likewise extends parallel to the longitudinal axis of the measuring roll. However, embodiments are also conceivable in which the radial recess of the first force sensor is arranged axially (radially relative to the longitudinal axis of the measuring roll) and circumferentially offset relative to the radial recess of the second force sensor. In such embodiments, the line connecting the point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and the point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor does not run parallel to the longitudinal axis of the measuring roll. Such an orientation of the line also occurs with elongated recesses whose longitudinal axis does not run parallel to the longitudinal axis of the measuring roll body, but has a circumferentially oriented component.

In a preferred embodiment, the line connecting the point on the sensor surface of the first force sensor closest to the sensor surface of the second force sensor and the point on the sensor surface of the second force sensor closest to the sensor surface of the first force sensor extends at an angle to a plane extending perpendicular to the longitudinal axis of the measuring roll, preferably at an angle greater than 1 °, particularly preferably at an angle greater than 5 °, particularly preferably at an angle greater than 10 °, particularly preferably at an angle greater than 15 °, particularly preferably at an angle greater than 20 °, particularly preferably at an angle greater than 25 °, particularly preferably at an angle greater than 30 °, particularly preferably at an angle greater than 45 °. In a preferred embodiment, this angle is less than or equal to 90 °. If this angle is 90° according to a particularly preferred embodiment, the line connecting the point on the sensor surface of the first force sensor closest to the sensor surface of the second force sensor and the point on the sensor surface of the second force sensor closest to the sensor surface of the first force sensor runs parallel to the longitudinal axis of the measuring roll. In a preferred embodiment, the point on the sensor surface of the first force sensor closest to the sensor surface of the second force sensor and the point on the sensor surface of the second force sensor closest to the sensor surface of the first force sensor are not located one behind the other in the circumferential direction.

The recognition according to the invention can be expressed in terms of the height of the web for the embodiment in which the sensor surface is in contact with the recess boundary surface located closest to the circumferential surface of the measuring roll body, where web means the material between the circumferential surface of the measuring roll body and the recess boundary surface located closest to the circumferential surface of the measuring roll body. The height of the web may be 2 mm or more, preferably 5 mm or more, and preferably 20 mm or less, preferably 15 mm or less, particularly preferably 12 mm or less. In an alternative way of expressing the recognition according to the invention, the point of the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor is separated from the point of the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor by less than 2.2 times the web height, preferably less than 2 times the web height, particularly preferably less than 1 time.

In a preferred embodiment, the first and second force sensors are arranged in a recess that runs from one end face of the measuring roll body to the opposite end face of the measuring roll body. In an alternative configuration, the recess in which the first and second force sensors are arranged runs parallel to the longitudinal axis of the measuring roll body and extends over at least 50%, particularly preferably at least 60%, particularly preferably at least 75%, particularly preferably at least 80%, particularly preferably at least 90%, particularly preferably at least 95% of the length of the measuring roll body that would be obtained if the length of the measuring roll body were measured from end face to end face (i.e. without taking into account the journals).

In an embodiment in which the measuring roll has a number of recesses, all recesses are conceivable in a similar manner, i.e. in a longitudinal extension parallel to one another and of the same length. In an alternative embodiment, the measuring roll with a number of recesses is conceivable in such a way that at least one recess is designed to meet the above-mentioned design provisions, i.e. to extend over at least 50%, particularly preferably over at least 60%, particularly preferably over at least 75%, particularly preferably over at least 80%, particularly preferably over at least 90%, particularly preferably over at least 95% of the length of the measuring roll body obtained when the length of the measuring roll body is measured from end face to end face (i.e. without taking into account the journals), and the other recesses are conceivable to be designed shorter. Figure 5 of DE 102 07 501 shows the possibility of spirally grading the depth of the recesses. Such an embodiment can be supplemented with the following regarding the selection of the length of the recesses: the axially extending recesses shown here are designed to extend from one end face of the measuring roll to the opposite end face.

In a preferred embodiment, the recess has an opening arranged on one end face of the measuring roll body. This recess may be formed in an open state. However, a configuration in which the recess is closed by a cover is also conceivable. If several recesses are provided that open on the end face, in this embodiment, each recess has its own cover. In particular in such an embodiment, an embodiment of the measuring roll according to the invention is also conceivable in which the measuring roll has several recesses, in which the measuring roll body has an end cover for closing the openings of the recesses together, for example as shown in FIG. 1 or FIG. 2 of DE 102014012426 A1. Likewise, in particular with regard to an embodiment in which the measuring roll has several recesses, it is conceivable that these recesses each have an opening arranged on one end face of the measuring roll body, which openings are closed by an end cover, for example as shown in FIG. 1 of DE 10207501 A1.

In a preferred embodiment, the measuring roll has a number of force sensors all arranged in one recess. Particularly preferred is more than 5, particularly preferably more than 7, particularly preferably more than 10, particularly preferably more than 15 force sensors arranged in one recess.

In a preferred embodiment, the measuring roll has a first recess, in which a number of force sensors are arranged adjacent to one another, particularly preferably more than 5, particularly preferably more than 7, particularly preferably more than 10, particularly preferably more than 15 force sensors are arranged in the first recess, and in this embodiment the measuring roll has further recesses, in which only one force sensor is arranged or in which fewer than 15, particularly preferably fewer than 10, particularly preferably fewer than 7, particularly preferably fewer than 5 force sensors are arranged.

In a preferred embodiment of the measuring roll in which several force sensors are arranged in one recess, the force sensors are distributed equidistantly over the length of the recess, and at least equidistantly from each other (for embodiments in which the distance of the last force sensor to the end of the recess does not correspond to the distance that this last force sensor has from its neighboring (next to last) force sensor). However, embodiments are also conceivable in which the force sensors of the first group are arranged equidistantly from each other and the force sensors of the second group are arranged at different distances from the force sensors of the first group, in which case the force sensors of the second group can also be arranged equidistantly from each other. Thus, a predefined zone can be formed inside the recess, inside which the force sensors are arranged closer to each other, and further force sensors provided outside this zone are arranged more widely spaced from each other.

The embodiment with several force sensors can also be replaced by the basic type according to the invention of the measuring roll, in which the force sensors are arranged in pockets, in which several, particularly preferably more than 5, particularly preferably more than 7, particularly preferably more than 10, particularly preferably more than 15 pockets are arranged adjacent to one another, in which each one of the force sensors arranged in each pocket has an end boundary line extending in the radial direction of the measuring roll and intersecting with a point of the sensor surface of the respective force sensor that is closest to the sensor surface of the respective force sensor adjacent to the respective force sensor,
- extend in a plane including the edge boundary line and a line connecting the point of the sensor surface of the respective force sensor that is closest to the sensor surface of the adjacent force sensor and the point of the sensor surface of the respective force sensor that is closest to the sensor surface of the adjacent force sensor, and - intersect the edge boundary line at the intersection of the edge boundary line with the circumferential surface, and - be close to the adjacent force sensor located in the adjacent pocket to such an extent that the angle between the line intersecting the point of the sensor surface of the respective force sensor that is closest to the sensor surface of the respective force sensor is less than 65°. In a preferred embodiment, such a design rule is met by all the force sensors of this measuring roll. In an alternative embodiment, this design rule is met by some of the force sensors of the measuring roll, preferably by a plurality of force sensors, and there is provided another pocket with a force sensor located therein that does not meet this design rule. With regard to pockets with force sensors that meet the design rule, it is preferred if these pockets are arranged in one line, i.e. if the center points of the pockets are arranged on one line. This line preferably runs parallel to the longitudinal axis of the measuring roll body or in a spiral around the longitudinal axis of the measuring roll body. In an alternative embodiment, with respect to pockets with force sensors that meet the design regulations, the pockets are arranged offset with respect to one another, so that each subsequent pocket is located on a line with the respective pocket, and the subsequent pockets are arranged offset with respect to the respective pocket, preferably on a line with the subsequent pocket of this pocket. Such an arrangement allows the density of the pockets to be increased.

In a preferred configuration, the force sensor is wedge-fixed in the recess. This allows the force sensor, which in a particularly preferred embodiment can be loaded with a predefined preload. The force sensor is not only fixed in position at the position of the force sensor inside the recess by the wedge-fixing, but can also be loaded with a preload force. Loading with a preload force is preferred since, when the measuring roll is used in normal operation, the installation conditions for the force sensor can change under various operating conditions, for example due to temperature changes. Therefore, when the force sensor is installed in the recess, it is preferred to load it with a preload force of such a height that the force connection between the force sensor and the recess wall remains maintained under all operating influences during operation in order to ensure a linear measurement without hysteresis.

In a preferred embodiment, the force sensor should be fixed in position in the recess, i.e. wedge-fixed, and preferably preloaded by means of the wedge fixation. In a preferred embodiment, the wedge fixation is formed such that a preload is applied to the force sensor. This preload is particularly preferably selected to maintain a force connection between the force sensor and the recess wall under all operating influences during operational use, in order to ensure a linear measurement without hysteresis.

If different preloads occur during tightening, these can be easily compensated for using measurement technology. On the other hand, however, the preload can be intentionally adjusted in order to compensate for manufacturing errors of the force sensor and the recess. In this case, a force sensor with plane-parallel surfaces can be arranged between wedge-shaped holding elements, for example tightening wedges, which are moved relative to one another until the force sensor is immovably clamped between the holding elements.

One of the two retaining members is usually placed in a fixed position in the recess where the force sensor is to be located, and the other retaining member is slid in until the force sensor is fixed in the recess. This can be done by a tension screw that is supported on the measuring roll body and acts on the movable retaining member via a spacer sleeve.

An arrangement of multiple force sensors in a radially movable slide member that is fixed in the recess by a wedge strip is particularly preferred. The slide member can be arranged in a spacer strip and can be pressed radially outward by the wedge-shaped retaining projections of the fastening strip and fastened in the recess.

To ensure a reliable attachment of the lines leading to the force sensor, the recesses can be connected to parallel running line passages. Alternatively, however, the recesses can also be connected via lateral passages to a central cable recess provided in the measuring roll. The lateral passages can run within the body of the measuring roll or can run as open passages at the end faces of the measuring roll, which can then be closed by covers.

To guide the retaining member or strip for the force sensor in the recess, the recess can be provided with longitudinal ribs which engage in complementary guide grooves in the body of the measuring roll.

In a preferred embodiment, the force sensor is held between two pairs of inner and outer wedge elements. This allows, on the one hand, the force sensor to be oriented in the direction of action of the pressing force to be measured. Furthermore, this arrangement allows the holder to be made geometrically symmetrical, possibly axially symmetrical, with respect to a plane that runs through the mounting position of the force sensor and is arranged perpendicular to the direction of action of the pressing force to be measured.

An advantage is already achieved by a holder for a force sensor capable of measuring a pressing force acting from above, which holder has the following components:
a first inner wedge element arranged above the mounting position provided for the force sensor, the first inner wedge element having an inner surface facing the mounting position of the force sensor and an outer surface facing said inner surface, which is angled with respect to said inner surface; and a first outer wedge element arranged below the mounting position provided for the force sensor, the second inner wedge element having an inner surface facing the mounting position of the force sensor and an outer surface facing said inner surface, which is angled with respect to said inner surface, and a second outer wedge element arranged below the mounting position provided for the force sensor, the second inner wedge element having an inner surface facing the mounting position of the force sensor and an outer surface facing said inner surface, which is angled with respect to said inner surface, and a second outer wedge element arranged below the mounting position provided for the force sensor, the second inner wedge element having an inner surface facing the mounting position of the force sensor and an outer surface facing said inner surface.

In this way, the wedge assembly required for the translational preloading of the holder and the force sensor in the recess is installed inside the holder. The outer surface of the holder can be adapted to the shape of the recess in which the holder and the force sensor are clamped, while the inner surface, which directly or indirectly influences the mounting direction of the force sensor, can be oriented as desired, for example perpendicular to the direction of action of the pressing force to be measured. Furthermore, it has been shown that with the holder according to the invention, the surface quality of the recess in which the holder is mounted (for example the axial recess) can be reduced without tilting. This eliminates the need for costly methods for producing a good surface quality, such as honing or spinning.

In a preferred embodiment, the holder is geometrically symmetrical with respect to a plane that runs through the mounting position of the force sensor and is arranged perpendicular to the direction of action of the pressing force to be measured. By adjusting the geometry of the components arranged above and below the force sensor, the tilting moment that occurs in the event of preloading can already be reduced or even completely eliminated.

Alternatively or additionally, the holder can be designed symmetrically with respect to a plane extending through the mounting position of the force sensor and arranged perpendicular to the direction of action of the pressing force to be measured, with respect to the materials used for the components forming the holder and/or with respect to the surface quality of these components. Tilting moments can arise not only due to geometric differences in the components provided above and below the force sensor, but also due to different friction forces arising between the surfaces moving against each other above and below the force sensor due to different material selections or different surface qualities. Such tilting moments can be prevented by designing the corresponding materials or surface qualities symmetrically.

In a preferred embodiment, a connection is provided that connects the first and second inner wedge elements in order to prevent relative sliding in a direction other than the direction of action of the pressure to be measured. The tilting moment to be prevented can also occur when comparable components on the upper side of the force sensor and on the lower side of the force sensor do not move synchronously with each other. This can be prevented by connecting the corresponding components to each other. However, such a connection is preferably formed in such a way that sliding of both connected components is possible in the direction of action of the pressure to be measured. In a holder for a force sensor for measuring a pressure acting from above, it is preferable to keep the branching of forces as small as possible by constructional measures, i.e. to keep the portion of the pressure to be measured that is transmitted through the holder and past the force sensor small. This is done by forming the components spring-like relative to each other in the direction of action of the pressure to be measured and by making the spring stiffness of the force bridge caused by the connection as small as possible.

In a further embodiment of the invention, a connection is provided for connecting the first and second outer wedge elements in order to avoid relative sliding in a direction other than the direction of action of the pressing force to be measured. This provides the same advantages as when connecting the inner wedge elements.

Although the outer surface of the first inner wedge element and/or the outer surface of the second inner wedge element can be formed flat in the form of a flat wedge, in a preferred embodiment the outer surface of the first inner wedge element and/or the outer surface of the second inner wedge element are formed as partial surfaces of a cone having a longitudinal axis extending through the mounting position of the force sensor. With regard to the tilting moment occurring under preload, it is important to what degree the geometry of the facing surfaces of the individual surfaces moving relative to one another can be produced. It has been shown that the production of conical partial surfaces, for example by turning or machining semi-finished products, can be produced more precisely than the flat surfaces of flat wedges. This special configuration of the outer surface therefore allows the resulting tilting moment to be further reduced.

For similar reasons, the inner surface of the first outer wedge element and/or the inner surface of the second outer wedge element are preferably formed as partial surfaces of the boundary of a conical recess having a longitudinal axis extending through the mounting position of the force sensor.

In a preferred embodiment, the first inner wedge element and the second inner wedge element are partial elements of an inner sleeve that are manufactured in one piece. This provides advantages with regard to the manufacture of the components of the holder and with regard to the handling of the holder during the installation of the force sensor.

In a preferred embodiment, the inner sleeve has a longitudinal slit between the first and second inner wedge elements, which extends substantially perpendicular to the direction of action of the pressing force to be measured. This reduces the spring stiffness of the inner sleeve, so that the force branching is kept small. Furthermore, the inner sleeve can be formed with a small wall thickness. A small wall thickness means, for example, a wall thickness of 0.3 mm to 5 mm for a typical inner diameter of, for example, 20 mm to 50 mm. The selected wall thickness of the sleeve can also be selected depending on the sleeve length, the sliding distance and the inclination. The wall thickness can be 1/10 mm at the thinnest point. In particular, the longitudinal slit can be formed in such a way that it has almost the entire longitudinal extension of the inner sleeve, leaving a thin web at one or both ends as a connection between the first and second inner wedge elements. In a preferred embodiment, the inner sleeve has two longitudinal slits. Preferably, the longitudinal slit is provided in a plane extending through the mounting position of the force sensor and arranged perpendicular to the direction of action of the pressing force to be measured.

As in the case of the inner wedge element, in a preferred embodiment, alternatively or additionally, the first outer wedge element and the second outer wedge element may be partial elements or parts of an integrally manufactured outer sleeve. The outer sleeve, in a preferred embodiment, may likewise have at least one longitudinal slit between the first outer wedge element and the second outer wedge element, which extends substantially perpendicular to the direction of action of the pressing force to be measured.

In a preferred embodiment, the inner surface of the first inner wedge element and/or the inner surface of the second inner wedge element are flat and are arranged in a plane perpendicular to the direction of action of the pressing force to be measured. With this configuration, a force sensor, the upper and lower surfaces of which are primarily flat, can be inserted between the two inner wedge elements by directly contacting the inner surfaces and sliding them between them.

Alternatively, in a further embodiment of the invention, a first intermediate part with a spherical crown can be provided between the first inner wedge element and the mounting position of the force sensor, and/or a second intermediate part with a spherical crown can be provided between the second inner wedge element and the mounting position of the force sensor, in which case the spherical crown forms a surface facing one of the inner surfaces of the inner wedge element and is formed to correspond to the associated inner surface of the inner wedge element. In this case, the spherical crown preferably has the geometric shape of a partial surface of the cylindrical body.

In a preferred embodiment of the invention, the outer surface of the first outer wedge element and/or the outer surface of the second outer wedge element are partial surfaces of a cylindrical body. Such an arrangement is particularly recommended in fields of use in which the force sensor is held in a recess by a holder, for example in an axial recess of a measuring roll.

The holder can have a centering pin which engages in a central recess in the component. Such a centering pin allows good and accurate positioning of individual loose components, such as force sensors, relative to other components, such as inner wedge elements or inner sleeves.

In a preferred embodiment, the holder has an internal thread provided in the first and second outer wedge elements and a compression screw screwed into the internal thread, the longitudinal axis of the internal thread extending through the mounting position of the force sensor, and the compression screw can contact the first inner wedge element and the second inner wedge element and can slide relative to the first and second outer wedge elements. This compression screw allows a preload of the holder to be generated in a simple manner. Due to the angular configuration of the respective outer surfaces of the cooperating inner and outer wedge elements compared to their respective inner surfaces, the sliding of the wedge elements relative to each other displaces the outer wedge element away from the mounting position of the force sensor. In this way, the holder can be tightened in the recess.

Alternatively, the holder has an internal thread provided in the first and second inner wedge elements and a tension screw screwed into the internal thread, the longitudinal axis of the internal thread extending through the mounting position of the force sensor, and the thread head of the tension screw can contact the first outer wedge element and the second outer wedge element and can slide relative to the first and second inner wedge elements.

In a preferred embodiment, two or more force sensors are provided in the measuring roll to measure the various mechanical forces. This allows the effects of temperature to be detected, which the inventors have realized can be sensed by measuring the mechanical forces present in the measuring roll and then calibrated accordingly. Thus, in addition to the other usual measurements of mechanical forces, a second mechanical force is measured that can be due to the effects of heat input from using the measuring roll with hot strip material. A measuring roll constructed according to the invention allows the proportion of the force caused by the heat input into the measuring roll body to be separated from the total signal of the force encoder.

The inventors have realized that according to a preferred embodiment, it is particularly preferred if one type of force sensor is a force sensor for measuring a radial force, and one type of force sensor is a force sensor for measuring a preload force of the force sensor for measuring a radial force. Tests have shown that temperature changes on the surface of the measuring roll lead to an elastic deformation of the measuring roll, whereby the force sensor for measuring a radial force, which is usually installed under a preload force, changes its preload force and therefore also its linearity. A force sensor for measuring a preload force applied to the force sensor for measuring a radial force of a different type from the first type allows the influence of thermal deformation of the measuring roll body to be measured and the proportion of the measurement signal of the force for measuring the radial force caused by thermal deformation to be separated from the radial force actually brought to the strip-like article.

The inventors further realized that if multiple force sensors are arranged in the longitudinal direction of the measuring roll, then a second type of force sensor measuring mechanical force can detect the relative temperature distribution across the width of the strip, in addition to the thermal deformation of the measuring roll, which affects the measurement result of the first type of force sensor. For example, for a heat input of 1°C, a value x of the unit N can be measured, which allows the temperature distribution to be determined in relation to the measured mechanical force.

Preferably, the force introduced by the strip-shaped article being pulled in the longitudinal direction is measured dynamically by one type of force sensor, and the force resulting from the deformation of the measuring roll as a result of the thermal input is measured statically by the other type of force sensor. This allows the radial force measured by one type of force sensor to be corrected by the thermal input or thermal deformation in relation to the respective actually measured forces.

In particular, a force sensor of one type can be fixed or clamped in the recess, for example by wedge clamping. This preload is predictable and can be easily compensated for by measurement technology. The preload can be adjusted by a predefined value. For example, a force sensor with plane-parallel surfaces can be arranged between wedge-shaped holding members, for example clamping wedges, which are moved relative to one another until the force sensor is immovably clamped between the holding members. Preferably, a force sensor of another type can be fixed or clamped in the recess together with the force sensor of the first type in a casing. The force sensor of another type can be mounted, for example, in a recess formed in one of the holding members, which clamps the force sensor of one type in the recess, or on one of the holding members.

One of the two retaining members can be positioned in a fixed position in the recess where the force sensor is to be located, and the other retaining member can be slid in to fix the force sensor in the recess. This can be done, for example, by means of a tension screw that is supported on the measuring roll body and acts on the movable retaining member via a spacer sleeve.

Particularly preferably, force sensors of various types are arranged next to each other in order to measure the direct influence of the heat input "in situ" and to use the influence on the signal of another force sensor as a correction value.

In a preferred embodiment, one type of force sensor is arranged together with another type of force sensor in or on the surface of the casing or in or on the surface of the holder, which simplifies handling during production. The casing can be arranged in a recess of the measuring roll. For example, one type of force sensor can already be preloaded in the casing, in which case the other type of force sensor is arranged on the first type of force sensor and can measure the preload force. The first type of force sensor can be preloaded in and/or with the casing, in which case the other type of force sensor can determine the preload of the casing and thus the heat input. If both types of force sensors are arranged in the casing or on the casing surface, it is also ensured that both types of force sensors are arranged adjacent to each other in order to accurately take into account the influences detected by one type of force sensor for the other type of force sensor.

The term "casing" according to the invention also includes holders that do not have the closed configuration of a normal casing. The casing according to the invention can be configured in particular as described in DE 10 2006 003 792 A1, the disclosure of which is expressly incorporated herein by reference, in which the casing or holder has an inner sleeve with an outer peripheral cone on which a force sensor for measuring radial forces (one type of force sensor) is arranged, and an outer sleeve with an inner peripheral cone that can engage with the inner sleeve or be clamped to the inner sleeve. For example, a force sensor for measuring mechanical forces acting against the radial forces (the other type of force sensor) can be arranged or attached in the inner sleeve or in a recess of the inner sleeve. For example, the force sensor can be glued. A force sensor for measuring mechanical forces acting against the radial forces (the other type of force sensor) can also be arranged in the outer sleeve or in a recess of the outer sleeve. A force sensor for measuring the mechanical force acting against the radial force (the other type of force sensor) can also be arranged in the recess of the measuring roll in the area of the location provided for the installation of the casing or holder, without being connected to the casing or holder itself.

In a preferred embodiment, the other type of force sensor is arranged to be in the flow of forces acting on the first type of force sensor. This arrangement should be in the flow of forces of one type of force sensor.

In a preferred embodiment, one type of force sensor is formed as a quartz force sensor, which is understood to be a piezoelectric element, at whose crystal surface the force to be measured generates an electric charge that is used as a measurement value. Such force sensors have small dimensions, high response sensitivity, high natural frequency, stability and can compensate for preloads without impairing the measurement result.

Preferably, one type of force sensor is formed as a strain gauge, which can measure the preload force of a quartz force sensor, which can change when the measuring roll is deformed, for example as a result of heat input into the measuring roll.

The measuring roll according to the invention is particularly suitable for use in determining the properties of a metal strip during its cold or hot rolling, in particular for determining the flatness of the metal strip. Further areas of application can be, for example, rerolling frames (skin pass frames), strip annealing lines, galvanizing lines, further processing lines such as stretching and straightening devices.

Next, the present invention will be described in more detail with reference to the illustrated embodiment.

FIG. 2 is a side view, partially in section, of a first embodiment of a measuring roll; FIG. 2 shows a perspective view of a measuring roll with cable passage with the cover removed; FIG. 3 is a diagram showing a portion of an end face of the measuring roll of FIG. 2 . FIG. 2 shows a measuring roll with force sensors arranged stepwise along a spiral in a perspective view with the cover removed; FIG. 13 is a detailed cross-sectional view of a force sensor disposed within a hole. FIG. 6 is a plan view showing the arrangement of the force sensors in FIG. 5 . FIG. 13 is a side view, partially in section, of another embodiment of a measuring roll. FIG. 10 is a cross-sectional view of the holder with the force sensor partially shown in a state of installation in the measuring roll in a side view cut along the line B-B in FIG. 9 . 8 along line AA of FIG. 8, showing the element of FIG. 8. 8 and 9 in a view taken along line CC of FIG. 9. FIG. FIG. 10 is a view comparable to FIG. 9 showing an alternative configuration of the holder. FIG. 9 is a view comparable to FIG. 8 showing another configuration of the holder. 13 is a view of the element of FIG. 12 taken along line AA of FIG. 12. 12 and 13 in a view taken along line CC of FIG. 12. FIG. 13 is a view comparable to FIG. 8 and FIG. 12 showing another configuration of the holder; FIG. FIG. 4 is a detailed view of a force sensor arranged in a recess of the measuring roll. FIG. 13 is a detailed view of another embodiment of a force sensor arranged in a recess of the measuring roll. FIG. 4 is a diagram showing the forces acting on a measuring roll.

The measuring roll 1 according to the invention has a measuring roll body 1a with journals 2 and formed as a solid roll. In the measuring roll body 1a, a recess 3 is provided which is formed as a hole axially parallel to the longitudinal axis A of the measuring roll body 1a, from which a transverse passage 4 leads out near the end face of the recess and leads to a central cable passage 5. The recess 3 is closed at the end face by a cover 6 or by a respective separate cover and has a first force sensor 7a, a second force sensor 7b arranged adjacent to the first force sensor 7a, a third force sensor 7c arranged adjacent to the second force sensor 7b, and a fourth force sensor 7d arranged adjacent to the third force sensor 7c, from which a cable 8 (shown only as one cable for the sake of simplicity) is guided to the outside through the hole 3, the transverse passage 4 and the central passage 5.

The measuring roll 1, shown in a schematic perspective view in Figures 2 and 3 with the cover 6 removed, has cable passages 10, 11 located opposite each other, parallel to each hole 3, for lines guided to the outside via the lateral passages 4 and the central passage 5.

As shown in Figures 4 and 5, the holes extend from both end faces of the roll 1 and have various depths as blind holes. This allows the individual sensors to be arranged along the spiral 20, i.e. in stages, and collectively detect the entire width of the roll 1.

Compared to the embodiment of Figures 1 to 3, the embodiment of Figures 4 and 5 has a roll body 1a formed as a solid roll with multiple grooves formed on the outer periphery, which are covered with a cover tube 1b that closes the grooves and forms a recess for the force sensor 7.

As shown in FIG. 4, each recess 3 can be formed in such a way that only one force sensor 7 is arranged therein. However, in the embodiment of FIG. 4, recesses 3 having multiple force sensors 7 are also provided. In the embodiment of FIG. 4, the recesses 3 are configured to run from one end face of the measuring roll body 1a to the opposite end face of the measuring roll body.

5 shows the arrangement of two force sensors 107a, 107b in a hole 103 in the measuring roll body 1a of a measuring roll, which is configured as a solid roll according to the construction shown in Figs. 1 and 2 and has an axial hole 103 in the solid roll. Each of the force sensors 107a, 107b shown in Fig. 5 has a casing 120. A socket 122 is attached to one side of each of the casings 120. Each of the force sensors 107a, 107b has a piezoelectric element 113, which consists of a multilayer crystal assembly. Each of the piezoelectric elements 113 is located between two force transmission disks 114, 115. The force transmission disks 114, 115 are connected to the casing 120 by elastic flanges 116. The sensor surface of the force sensor 107a is the outer surface of the force transmission disk 114, which contacts the wall of the hole 103. The sensor surface of the force sensor 107b is the outer surface of the force transmission disk 114, which is in contact with the wall of the hole 103.

In Fig. 5, for the force sensor 107a, an edge boundary line 117 is drawn, which runs in the radial direction of the measuring roll and which intersects with the point of the sensor surface of the first force sensor 107a which is closest to the sensor surface of the second force sensor 107b. Furthermore, in Fig. 5, a line 118 is drawn, which corresponds to
- extends in a plane including the end boundary line 117 and a line connecting a point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and a point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor; and - intersects the end boundary line 117 at an intersection 119 between the end boundary line 117 and the peripheral surface;
- It intersects the point on the sensor surface of the second force sensor 107b that is closest to the sensor surface of the first force sensor 107a.

As shown in FIG. 5, the angle α between the end boundary line 117 and the line 118 is less than 65°, i.e., approximately 45°.

The hole 103 is formed with a rectangular cross section so that the annular, flat sensor surfaces of the force sensors 107a and 107b can abut against the walls of the hole 103.

Figure 6 shows a schematic plan view of the force sensors 107a and 107b arranged in the hole 103, cut at the height of the upper hole wall. In this case, a line 123 is drawn in Figure 6 connecting the point on the sensor surface of the first force sensor 107a that is closest to the sensor surface of the second force sensor 107b and the point on the sensor surface of the second force sensor 107b that is closest to the sensor surface of the first force sensor 107a. The sensor surface of the force sensor 107a is the outer surface of the force transmission disk 114 that is in contact with the hole wall of the hole 103. The sensor surface of the force sensor 107b is the outer surface of the force transmission disk 114 that is in contact with the hole wall of the hole 103.

7 has a measuring roll body 201a formed as a solid roll, the circumference of which is provided with a number of recesses 203, 203a, 203b distributed over the roll width, in which an encoder, for example a distance or force or piezo encoder 207 in the form of a quartz washer for measuring dynamic and static forces, is mounted together with a cylindrical cover 234. The encoder 207 extends between the bottom surface 239 of the recess 203 and the cover 234. The cover 234 has a recess in which the head 236 of a tightening screw 237 is located, which engages in a threaded hole 238 of the measuring roll 201. The tightening screw 237 tightens the cover 234 together with the encoder 207 towards the bottom surface 239 of the recess 203.

The cover 234 is provided with a plastic layer 240. A gap 241 is created between the encoder 207 and the wall of the recess 203 of the roll 201 due to the difference between the diameter of the encoder and the diameter of the recess 203, and this gap is closed from the outside by the plastic layer 240 or in other ways when the cover is attached. A gap may also be created between the encoder cover and the wall of the recess.

Figure 7 shows holes 203b arranged side by side on a line extending parallel to the longitudinal axis A of the measuring roll body 201a. A line connecting the point on the sensor surface of each force sensor 207 in one recess 203b that is closest to the sensor surface of the adjacent force sensor 207 in the adjacent recess 203b and the point on the sensor surface of the adjacent force sensor 207 in the adjacent recess 203b that is closest to the sensor surface of each force sensor 207 in the aforementioned recess 203b extends parallel to the longitudinal axis A of the measuring roll body 201a in the case of these holes 203b.

However, FIG. 7 shows holes in the form of holes 203a that are adjacent to each other but are not arranged on a line extending parallel to the longitudinal axis A of the measuring roll body 201a. The line connecting the point on the sensor surface of each force sensor 207 in the recess 203a that is closest to the sensor surface of the adjacent force sensor 207 in the adjacent recess 203a, projected parallel to a plane containing the longitudinal axis A of the measuring roll body 201a, and the point on the sensor surface of the adjacent force sensor 207 in the adjacent recess 203a that is closest to the sensor surface of each force sensor 207 in the aforementioned recess 203a, extends at an angle to the longitudinal axis A of the measuring roll body 201a in the case of these holes 203a.

The measuring roll body 201a can be configured to have a coating, not shown, to form a closed circumferential surface.

In FIG. 7, further individually formed holes 203 are provided. FIG. 7 thus shows that various arrangements of holes 203, 203a, 203b can be integrated on one measuring roll depending on the desired measurement task. However, configurations in which only holes 203b or only holes 203a are provided are also conceivable.

8 shows a holder 1101 for a force sensor 1102. The holder 1101 holds the force sensor 1102 in an axial bore 1103 of a partially shown measuring roll 1104. The holder 1101 has an inner sleeve 1105 with a first inner wedge element 1106 arranged above the mounting position provided for the force sensor 1102, the inner wedge element having an inner surface 1107 facing the mounting position of the force sensor 1102 and an outer surface 1108 facing the inner surface 1107 at an angle to the inner surface 1107. Furthermore, the inner sleeve 1105 has a second inner wedge element 1109 arranged below the mounting position provided for the force sensor 1102, the inner wedge element having an inner surface 1110 facing the mounting position of the force sensor 1102 and an outer surface 1111 that is angled relative to the inner surface 1110 and faces the inner surface 1110.

The holder 1101 further comprises an outer sleeve 1112. The outer sleeve 112 comprises a first outer wedge element 1113 having an inner surface 1114 facing the mounting position of the force sensor and an outer surface 1115 that is angled with respect to the inner surface 1114 and faces the inner surface 1114. The outer sleeve 1112 further comprises a second outer wedge element 1116 having an inner surface 1117 facing the mounting position of the force sensor 1102, with the second outer wedge element 1116 resting with the inner surface on the outer surface of the second inner wedge element 1109. The outer wedge element 1116 further comprises an outer surface 1118 facing the inner surface 1117.

A compression screw 1119 with an external thread is threaded into an internal thread 1120 on the outer sleeve. The threading depth of the compression screw 1119 determines the relative position of the inner sleeve 1105 with respect to the outer sleeve 1112 and thus the degree of preload of the holder 1101 in the axial recess 1103.

As can be seen from FIG. 9, the inner sleeve 1105 and the outer sleeve 1112 have slits 1121 and 1122. These longitudinal slits 1121, 1122 reduce the spring stiffness of the inner sleeve 1105 and the outer sleeve 1112 and serve to keep the force branching small. The pressing force to be detected, acting in the direction of action of the arrow D, is thus well introduced into the force sensor 1102. The outer sleeve 1112 and the inner sleeve 1105 are produced by turning in a first work step. This allows for particularly precise production, particularly with regard to the geometrical tolerances of the inner surfaces 1114, 1117 of the outer sleeve 1112 and the outer surfaces 1108, 1111 of the inner sleeve, and allows a tilting moment-free movement of the inner sleeve 1105 relative to the outer sleeve 1112. In a subsequent processing step, the regions of the inner sleeve 1105 located laterally as viewed in FIG. 9 can be further thinned in order to reduce the lateral wall thickness of the inner sleeve 1105. This results in lateral spaces 1123, 1124 as viewed in FIG. 9 between the inner sleeve 1105 and the outer sleeve 1112, which optimize the introduction of forces into the force sensor 1102 and further reduce the branching of forces.

10 shows a top view of the force sensor 1102. In this view, the routing of the cables leading to the force sensor 1102 can be clearly seen. A first cable 1125 leads to the illustrated force sensor 1102, and another cable 1126 leads to another force sensor (not shown) located in the same axial recess 1103.

The alternative configuration of the holder shown in FIG. 11 has essentially the same structure as the holder shown in FIGS. 8 to 10. The same components have reference numbers that are 100 higher. However, in the inner sleeve 1205 of this second embodiment, a number of cavities 1226 are provided, which further reduce the lateral wall thickness of the inner sleeve 1205, thus resulting in a further reduction in the spring stiffness and thus in a further reduction in the branching of forces.

Figures 12 to 14 show another embodiment of the invention, which differs from the embodiment shown in Figures 8 to 10 in that intermediate parts 1327 and 1328 with spherical crowns are provided between the inner sleeve 1305 and the force sensor 1302. In other respects, the illustrated components correspond to the components of the parts shown in Figures 8 to 10. These components are designated by reference numbers 200 higher.

Figure 15 shows a holder 1401 comparable to that shown in Figure 8. It differs from that shown in Figure 8 by the different orientation of the inner faces 1408, 1411 and the corresponding outer faces 1414, 1417, as well as by the tension screw 1429, which is screwed into the internal thread 1430 of the inner sleeve 1405. The screwing depth of the tension screw 1429 into the internal thread 1430 determines the position of the inner sleeve 1405 relative to the outer sleeve 1412 and thus the preload of the holder 1401 in the axial bore 1403 of the measuring roll 1404. Elements that are the same as those shown in Figures 8 to 10 are designated with a number 300 larger.

16 shows another configuration of the embodiment of FIG. 8, showing a detailed view of the force sensors 1102a, 1102b arranged in a pair in the recess 1103 of the measuring roll. The casing 1101 or holder holds a first type of force sensor 1102a, which is designed to measure radial forces, in the recess 1103 of the measuring roll, which is partially shown. The casing 1101 has an inner sleeve 1105 with a first inner wedge element 1106 arranged above the mounting position provided for the force sensor 1102a, which has an inner surface 1107 facing the mounting position of the force sensor 1102a and an outer surface 1108 facing the inner surface 1107, which is angled with respect to the inner surface 1107. Furthermore, the inner sleeve 1105 has a second inner wedge element 1127 arranged below the mounting position provided for the force sensor 1102a, the inner wedge element having an inner surface 1110 facing the mounting position of the force sensor 1102a and an outer surface 1111 that is angled relative to the inner surface 1110 and faces the inner surface 1110.

The casing 1101 further comprises an outer sleeve 1112, which comprises a first outer wedge element 1113 having an inner surface 1114 facing the mounting position of the force sensor 1102a and an outer surface 1115 angled relative to the inner surface 1114 and facing the inner surface 1114. The outer sleeve 1112 further comprises a second outer wedge element 1120 having an inner surface 1117 facing the mounting position of the force sensor 1102a, with the outer wedge element 1120 resting with the inner surface on the outer surface of the second inner wedge element 1127. The outer wedge element 1120 further comprises an outer surface 1116 facing the inner surface 1117.

A compression screw 1119 with an external thread is screwed into an internal thread provided in the outer sleeve 1112. The screw-in depth of the compression screw 1119 determines the relative position of the inner sleeve 1127 with respect to the outer sleeve 1112 and thus also the degree of preload of the casing 1101 in the recess 1103. To detect the preload, a force sensor 1102b in the inner sleeve 1127 is arranged in the recess of the inner sleeve. The force sensor 1102b allows the preload to be measured.

The force sensor 1102a for measuring the radial force is preloaded, the extent of which can be detected by the force sensor 1102b. For example, when heat is applied during the processing of a metal strip during hot rolling, the deflection of the strip under tension in the longitudinal direction introduces a radial force into the measuring roll, which elastically deforms the outer skin of the measuring roll. The web formed "diaphragm-like" above the recess 1103 is then displaced radially, which can be detected by the force sensor 1102a, which can be formed as a piezoelectric force sensor. Thermal stresses caused by the thermal gradient also cause a radial distance change in the web located circumferentially outward above the recess 1103, which counteracts the radial force. This changes the measurement result of the force sensor 1102a, and the change in distance due to the change in preload can be detected by the force sensor 1102b, which can be formed as a statically measuring force sensor, in particular as a strain gauge. The radial force value of the force sensor 1102a can be corrected each time based on the actually measured preload.

The pair of force sensors 1102a, 1102b arranged adjacent to each other are mounted in a casing 1101 having an inner sleeve 1127 and an outer sleeve 1112, and are then positioned in a recess 1103 of the measuring roll 1 and tightened in position.

17 shows a detailed view of the force sensors 1102a and 1102b arranged in the recess 1103 of the measuring roll 1 in a different embodiment from that of FIG. 16. The configuration of the embodiment as shown in FIG. 17 substantially corresponds to the configuration of the embodiment shown in FIG. 16. Only with regard to the arrangement and configuration of the force sensors 1102a and 1102b, the embodiment of FIG. 17 differs from the force sensors 1102a and 1102b of FIG. 16. The force sensor 1107a is configured as a piezoelectric force sensor and is somewhat shorter in the radial direction than the force sensor 1102a of FIG. 16. As another type of force sensor, the force sensor 1107b is provided, which is configured as a statically measuring force sensor, in particular as a strain gauge.

Figure 18 shows the force exerted on the measuring roll by a metal strip partially wrapped around the measuring roll under strip tension. A quartz force sensor located in a recess in the measuring roll generates an electric charge that is directly proportional to the force exerted on the quartz.

The strip length deviation, usually measured in I-units, which is commonly used to represent strip flatness, is calculated using the following relationship:

Local radial force N
F _{R, i}

Localized tensile force N
F _Z,i =F _R,i /(2×sin α/2)
α = belt deflection angle around the measuring roll

Local tensile stress N/ ^mm2
σ _Z,i =F _Z,i /(b _El ×d)

b _El = measurement area width d = band thickness

Tensile stress deviation N/ ^mm2
Δσ _Z,i =σ _Z,max ×σ _Z,i

σ _{Z, max} = maximum local constant tensile stress

Strip length deviation μm/m
ΔL/L _i =(Δσ _Z,i /E)×10 ⁶
E = Modulus of elasticity (modulus of elasticity of steel = 2.06 x ¹⁰⁵ N/ ^mm2 )

Band length deviation I-Unit
ΔL/L _i =(Δσ _Z,i /E)×10 ⁵
E = Modulus of elasticity (modulus of elasticity of steel = 2.06 x ¹⁰⁵ N/ ^mm2 )

Example: Quartz force sensor: Sensitivity = 4.2 pC/N
Sensor charge:=210 pC
Force applied to the sensor: F _R,i = 50N
F _Z,i =50/(2×0.342/2)=146.19Nα=20°σ _Z,i =146.19/(25×0.5)=11.69N/mm ² b _El =25mm, d=0.5mmΔσ _Z,i =20-11.69=8.3N/mm ² σ _{Z, max} = 20N/mm ²
ΔL/L _i = (Δσ _Z,i /E)×10 ⁶ = 162.34 μm/m E = Elastic modulus (elastic modulus of steel = 2.06×10 ⁵ N/mm ² )
ΔL/L _i =(Δσ _{Z, i} /E)×10 ⁵ =16.234 I-Unit

Claims (13)

A measuring roll for detecting a characteristic of a strip-shaped article guided through said measuring roll, said measuring roll comprising:
a measuring roll body formed as a solid roll and having a peripheral surface;
at least one recess in the measuring roll body, the recess being spaced apart from the circumferential surface or leading from the circumferential surface into the interior of the measuring roll body; and a first force sensor disposed in the recess, and a second force sensor disposed in the recess or in another recess adjacent to the recess.
It has
a first force sensor having a sensor surface, the first force sensor being capable of generating a sensor signal when a position of the sensor surface of the first force sensor changes, and a second force sensor having a sensor surface, the second force sensor being capable of generating a sensor signal when a position of the sensor surface of the second force sensor changes,
the first force sensor is disposed adjacent to the second force sensor in the recess, the sensor surface of the first force sensor being adjacent to the sensor surface of the second force sensor;
Alternatively, the first force sensor is disposed in close proximity to the second force sensor such that an angle between a first line, which is a line that extends in a radial direction of the measuring roll and intersects a point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor, and a second line is less than 65°;
The second line is
extends in a plane including a line connecting a point on the sensor surface of the first force sensor that is closest to the sensor surface of the second force sensor and a point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor, and the first line; and
intersects the first line at an intersection point between the first line and the perimeter; and
a measuring roll intersecting a point on the sensor surface of the second force sensor that is closest to the sensor surface of the first force sensor. The measuring roll according to claim 1, wherein the measuring roll body is a solid roll extending along one longitudinal axis, and the recesses extend parallel to the longitudinal axis. The measuring roll according to claim 1 or 2, wherein the recess has an opening disposed on one end surface of the measuring roll body. a plurality of force sensors each having a sensor surface and each capable of generating a sensor signal when the position of the respective sensor surface of the plurality of force sensors changes are arranged in the recess or in recesses adjacent to each other,
the sensor surface of one force sensor is adjacent to the sensor surface of a force sensor adjacent to the force sensor;
or each of the force sensors extends in a radial direction of the measuring roll and is disposed adjacent to a force sensor adjacent to the respective force sensor such that an angle between a first line intersecting a point on the sensor surface of the respective force sensor closest to the sensor surface of the force sensor adjacent to the respective force sensor and a second line is less than 65°;
The second line is
extends in a plane including a line connecting a point on the sensor surface of the respective force sensor that is closest to the sensor surface of the adjacent force sensor and a point on the sensor surface of the respective force sensor that is closest to the sensor surface of the adjacent force sensor, and the first line; and
intersects the first line at an intersection point between the first line and the perimeter; and
4. The measuring roll according to claim 1, wherein the force sensor is disposed adjacent to the respective force sensor at a point on the sensor surface of the respective force sensor that is closest to the sensor surface of the respective force sensor. For each force sensor within the recess,
the sensor surface of the force sensor is adjacent to the sensor surface of a force sensor adjacent to the force sensor;
or each of the force sensors extends in a radial direction of the measuring roll and is disposed adjacent to a force sensor adjacent to the respective force sensor such that an angle between a first line intersecting a point on the sensor surface of the respective force sensor closest to the sensor surface of the force sensor adjacent to the respective force sensor and a second line is less than 65°;
The second line is
extends in a plane including a line connecting a point on the sensor surface of the respective force sensor that is closest to the sensor surface of the adjacent force sensor and a point on the sensor surface of the respective force sensor that is closest to the sensor surface of the adjacent force sensor, and the first line; and
intersects the first line at an intersection point between the first line and the periphery; and
5. The measuring roll of claim 4 , intersecting a point on the sensor surface of the force sensor adjacent to the respective force sensor that is closest to the sensor surface of the respective force sensor. The measuring roll according to any one of claims 1 to 5, wherein the first force sensor and the second force sensor are each a piezoelectric force sensor, a strain gauge, or an optical force sensor. The measuring roll according to any one of claims 1 to 6, wherein the first force sensor is preloaded and embedded in the recess. 8. The measuring roll according to claim 1, wherein the force sensors arranged so close together that the angle between the first line and the second line is less than 65° are arranged in the same recess. 1. A method for detecting a characteristic of a strip of an article guided through a measuring roll, comprising the steps of:
The belt-shaped article is guided through a measuring roll according to any one of claims 1 to 8 so that the belt-shaped article is partially wrapped around the measuring roll;
supplying a sensor signal generated by the first force sensor due to a change in the position of a sensor surface of the first force sensor caused by a pressing force generated by the wrapping to an evaluation unit;
supplying a sensor signal generated by the second force sensor due to a change in the position of a sensor surface of the second force sensor caused by a pressing force generated by the wrapping to an evaluation unit;
4. A method according to claim 3, wherein the evaluation unit generates information dependent on the sensor signal of the first force sensor and on the sensor signal of the second force sensor. 9. Use of a measuring roll according to claim 1 for determining a property of a strip of material guided over the measuring roll. 9. The measuring roll according to claim 1, wherein the strip-shaped article guided through the measuring roll is a metal strip. 10. The method of claim 9, wherein the strip-shaped article guided through the measuring roll is a metal strip. 11. Use of a measuring roll according to claim 10 for detecting the flatness of a strip-shaped article, the strip-shaped article being guided through the measuring roll being a metal strip.

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