MEASURING UNIT AND METHOD FOR MEASURING STRAIGHTENED WIRE-SHAPED OR PIPE-SHAPED MATERIALS - Patent application

Abstract

The measuring unit (350) for measuring the residual curvature of the straightened wire-shaped or pipe-shaped workpiece that has passed through a straightening system having two tandemly connected adjustable roller straighteners (400-1, 400-2) with differently oriented straightening planes accommodates the rod-shaped sections (110-A) of the workpiece that has passed through the straightening system, separated from the workpiece, at a measuring position, and has a measuring device (520) for determining measurement data representative of the residual curvature of the straightened workpiece. The measuring unit is configured for straightening-plane-specific measurement, which allows the curvature components represented by the measurement data to be associated with the different straightening planes of the roller straighteners.

Description

[Technical field]

[0001] The present invention relates to a measuring unit and a measuring method for measuring the residual curvature of a wire- or pipe-shaped workpiece that has been straightened by passing through a straightening system having two successively connected roller straighteners with differently oriented straightening planes. [Background technology]

[0002] Immediately after production, wires, pipes and other elongated semi-finished materials are often present in the form of wound material stock (coils) which usually have to be straightened before further processing. Straightening is a manufacturing process belonging to the group of forming processes, which is used to give elongated materials, also referred to here as straightened material, as much of the straight shape as possible, i.e. with little or no residual curvature, before further processing. To this end, in the straightening process, the material is transferred from the material stock through a straightening system which deforms the material by a straightening action, thereby producing a straightened material or a straightened material.

[0003] Straightening systems of the type considered in this application have at least two roller straighteners. The roller straighteners have a number of passive, i.e. not driven in rotation, straightening rollers with mutually parallel rotation axes, which are arranged alternately on both sides of the pass section in the pass direction and define the straightening geometry by the circumferential sections that contact the workpiece during the drive. With the roller straighteners, it is possible to change the one-dimensional input curvature of the straightened material (the curvature before entering the roller straightener) in one plane, so that after the straightening process there is a defined residual curvature in this plane. To a large extent, a final product without residual curvature, i.e. a straight final product, is desired. To a large extent, straightening systems are used with two successively connected roller straighteners, whereby the input curvature in two mutually perpendicular planes is eliminated.

[0004] Straightening systems with roller straighteners do not rotate and in this respect differ in principle from rotating straightening systems with so-called straightening vanes, which provide straightening forces in many different planes.

[0005] In adjustable roller straighteners, at least one of the straightening rollers can be delivered in a feed direction perpendicular to the pass direction, thereby allowing the straightening geometry of the roller straightener to be changed to obtain better straightening results. Depending on the type of roller straightener, the straightening rollers can be delivered manually, semi-automatically or automatically in response to control signals from a control unit using associated actuators (e.g. servo motors, pneumatic cylinders, hydraulic cylinders, etc.).

[0006] Inadequate straightening results can occur when starting to use new straightened material, for example after a coil exchange or after switching over to another process. Even while the process is ongoing, material inhomogeneities, changes in material properties and / or wear of the straightening rollers can lead to a deterioration of the straightening result. The raw material is also subject to manufacturing tolerances. Changes can be recognized by regular inspections with random samples. If an unacceptable deterioration of the straightening quality occurs, the straightening system has to be better adjusted by changing the straightening geometry.

[0007] In fact, a machine operator needs a lot of experience and skill to ensure stable straightening quality on the machine he or she is in charge of. There are already many studies to realize a manufacturing process with highly reproducible straightening quality regardless of the ability of the machine operator.

[0008] DE 19503850 C1 describes a non-rotating straightening machine for a bending machine with an integrated measuring device. The straightening machine has at least one non-rotating straightening device for wire or band material, which operates in at least one straightening plane. The straightening device has a number of successive straightening rollers for processing the material, which are adjustable by at least one actuator in the straightening plane and transversely to the axis of passage of the material. A material bending measuring device is provided behind the straightening device in the material passage direction, in which a measuring section is provided for a material section of a predetermined length and along which at least one mechanical and / or electronic and / or optical scanning device is arranged for determining the degree and direction of bending, by means of which a signal can be generated which is representative of the measured bending of the material section, and the actuator of the at least one straightening roller is an actuator which performs a corrective operating movement in response to the signal. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] German Patent No. 19503850 (C1) Summary of the Invention [Problem to be solved by the invention]

[0010] The object of the present invention is to provide a measuring unit and a measuring method for measuring straightened wire- or pipe-shaped workpieces, which allows accurate measurement of the residual curvature of the straightened workpiece and provides meaningful measurement results, which can be utilized in the adjustment and drive of the straightening system to quickly and systematically optimize the straightening geometry of the roller straightener and thus obtain good straightening results. [Means for solving the problem]

[0011] This problem is solved according to the present invention by a measuring unit having the features of claim 1 and by a measuring system having the features of claim 11. The wording of all claims is incorporated by reference into the content of this description.

[0012] The measuring unit and the measuring method are suitable for measuring the residual curvature of a straightened wire- or pipe-shaped workpiece that has passed through a straightening system having (at least) two successively connected roller straighteners with differently oriented straightening planes, preferably the straightening planes being oriented perpendicular to one another, in particular one of the straightening planes being horizontal and the other being vertical.

[0013] The measurements are carried out on rod-shaped sections (rods) of a predeterminable length (rod length) which are separated by a cutting device from the straightened material which has passed through the straightening system. Each individual rod is measured.

[0014] The measuring unit has a measuring device which receives the respective bar-shaped section at a measuring position and determines measurement data which are representative of the residual curvature of the straightened workpiece.

[0015] The particularity is that the measuring unit is designed for straightening-plane-specific measurements, which allows an at least approximately unambiguous assignment of the measurement data or the curvature components represented by the measurement data to the different straightening planes of the roller straightening tool.

[0016] The invention is based in particular on the following considerations:

[0017] A roller straightener performs straightening only in a single straightening plane. If the straightening system comprises two successively passed roller straighteners with different straightening planes, in particular those oriented perpendicularly to one another, the curvatures in the two straightening planes can be determined independently of one another in a first approximation. For the purposeful adjustment or adjustment of the straightening rollers in the adjustment process or within the framework of a closed-loop control during the drive, it is known that it is important to be able to uniquely assign the measurement results determined on the straightened workpiece to the respective straightening plane. Measuring methods and measuring devices which make this possible are referred to in this application as "straightening-plane-specific measurement" or "straightening-plane-selective measurement".

[0018] It is known to measure the straightness or residual curvature of a section of the straightened workpiece which is still connected to the adjacent parts of the workpiece. If necessary, the measurement can be performed during the passing, i.e. advancing, phase of the workpiece. Alternatively, the workpiece can be stopped for a short time for the measurement (see DE 19503850 C1). The inventor considers it a disadvantage that in that case the stresses and forces acting from other sections of the workpiece may strongly influence the shape of the section to be measured, so that the true state of curvature is not measured.

[0019] According to the claimed invention, the measurement is carried out on a rod-like section or bar of a predeterminable length, which has passed through the straightening system and been separated from the straightened material by a cutting device. The straightened bar to be measured can relax without external forces due to being separated from the subsequent remaining part, so that the shape of the bar represents the true curved situation at least approximately without distortion. According to the inventors' findings, a better interpretable measurement result can be obtained if a relatively short section is separated from the straightened material and this bar is subsequently measured or straightness checked.

[0020] As a result, by means of a measuring method which is relatively simple to carry out and evaluate, an exact quantitative description of the curvature components can be obtained, which can be unambiguously assigned to the different correction planes during the evaluation.

[0021] The preferred bar length is usually much less than 1 meter, for example between 300mm and 700mm, depending on the stiffness of the straightened material.

[0022] Another advantage of this configuration can be considered as follows: Many conventional straightness measuring systems are designed to provide a comprehensive description of the curvature of the workpiece to be straightened, for example in order to distinguish between sufficiently straightened workpieces having the desired straightening quality and workpieces having an insufficient straightening quality. In contrast, the measuring unit or measuring method of the claimed invention can not only determine a rough value for the residual curvature, but also split the information on the residual curvature of the bar section obtained from the measurement into curvature components which can be unambiguously assigned to the individual straightening planes of the straightening system. This type of straightening-plane-specific or straightening-plane-selective measurement makes it possible to quantitatively determine which components of the determined residual curvature were introduced by which of the at least two straightening machines.

[0023] This information on the residual curvature of the straightened workpiece, classified according to the straightening plane, can then be used to carry out a targeted adjustment of the roller straightener, for example within the context of the adjustment of the straightening system, so that an appropriate adjustment of the straightening rollers is achieved with minimal experimentation. For example, if a straightening system has a first roller straightener with a vertically oriented first straightening plane and a second roller straightener connected thereto with a horizontal straightening plane, the horizontal and vertical components of the residual curvature can be quantified separately from each other using the measurement data. Thus, in the adjustment process, for example, if the determined residual curvature occurs mainly or exclusively in one of the straightening planes, the adjustment of the straightening rollers can be focused on the straightener whose straightening plane is affected by the excessive residual curvature. As already mentioned above, an important contribution to obtaining meaningful measurement results can be made by carrying out measurements on bars separated to an appropriate finite length. The straightened workpiece to be measured, i.e. the separated bar, can relax without external forces due to its separation from the remaining subsequent parts, so that the shape of the bar represents the true curvature situation at least approximately without distortion. To enable such measurements on a relaxed bar, some embodiments include a device for fixing the straightened bar-shaped workpiece to a first fixation point and a second fixation point spaced apart from the first fixation point, which are constructed and arranged such that only the vertical and horizontal positions of the bar-shaped workpiece are predetermined for each of the fixation points, such that no forces other than gravity are applied to the section of the bar-shaped workpiece located between the fixation points. Further provided is a device for measuring the position of the straightened workpiece in a measurement plane located between the first and second fixation points, and a device for determining the residual curvature using position data for the first and second fixation points and the position of the straightened workpiece in the measurement plane.

[0024] An almost force-free positional fixation of the kind proposed here gives the rod accommodated in the fixation a certain degree of freedom to orient in space, so that it can relax and form a curve. This is considered an important difference with respect to solutions in which the wire to be measured is measured in the area between two wire guides, which each tightly surround the wire on all sides and prevent possible oblique orientations.

[0025] The measuring unit can handle wires that have been separated by a cutting device belonging to another machine connected upstream in the process, for example a straightening and separating machine, the end product of which is a straightened rod. In these cases, a cutting unit dedicated to the measuring unit is not necessary.

[0026] According to a further development, the measuring unit has a cutting device for separating rod-shaped sections of a predeterminable length from the straightened material that has passed through the straightening system. The measuring device is connected downstream of the cutting device in the material flow direction. Due to the integrated cutting device, the measuring unit can be a self-contained unit that separates rod-shaped sections of the appropriate length from the straightened endless material and performs a straightness test or a measurement of the residual curvature on said sections.

[0027] The cutting device can be mounted together with the measuring device in or on a common frame of the measuring unit in order to form a functional unit which ensures a fixed positional relationship and which can be used, for example, as an adjustment station. An embodiment of a self-sufficient measuring unit of this kind is described in detail below.

[0028] In order to realize a straightening-plane-specific or straightening-plane-selective measurement, the measuring unit is preferably configured so that the straightened workpiece is measured in the rotational position in which it has passed through the straightening system. The term "rotational position" in this case refers to the rotational position or orientation with respect to the self-rotation of the workpiece around its longitudinal axis. Straightening-plane-specific measurement data can also be determined in that any rotation that may occur between separation and measurement is mechanically detected and the measurement data determined by the measuring device are subsequently corrected with respect to the direction of rotation. However, it is considered much simpler and more accurate to eliminate this type of self-rotation by method-technical and structural measures.

[0029] For the measurement, a separated bar of an appropriate length is separated from the remaining part of the straightened workpiece, so that self-rotation of the bar about its longitudinal axis between the acts of separation and measurement should be avoided, thereby allowing an unambiguous assignment of the measurement result to the corresponding roller straightener. This can be problematic in particular when processing round workpieces, which are placed, for example, so that they roll along an inclined surface between separation and measurement. When processing materials with an uneven cross-section, for example a rectangular cross-section, simple measures are sufficient to prevent self-rotation, such as placing the workpiece with its flat side on a straight or flat rest.

[0030] According to a further development, the measuring unit is characterized by an anti-rotation device, which is configured in such a way that the rotational position of the bar section provided for measurement about its longitudinal axis does not change between straightening and measurement and the straightened material can be measured in its rotational position in which it has passed through the straightening system. The anti-rotation device and / or the anti-rotation measure thus ensure that the rotational position of the material about its longitudinal axis does not change between straightening and measurement.

[0031] According to a further development, the measuring unit has a control unit which is configured in such a way that in the drive mode, the cutting device and the measuring device are driven in a coordinated manner and are transported by a controlled feed to the measuring position in the measuring device, the front end section of the straightened workpiece is prevented from self-rotating by the anti-rotation device of the measuring device, for example by clamping, and only after that the cutting device is driven and the anti-rotation bar-shaped section to be measured is separated from the remaining part of the straightened workpiece. Clamping the workpiece before separation or another anti-rotation fixing means ensures that the separated workpiece is stationary.

[0032] The coordination between cutting and measuring is particularly easy to achieve by the integrated cutting device in the measuring unit, but also in terms of control technology, if the cutting device is external and therefore not an integral part of the measuring unit but belongs to another unit.

[0033] In many variants, the workpiece to be straightened is first transported into the area of ​​the measuring device, where it is accommodated against rotation and only afterwards is it separated from the remaining workpiece to be straightened. In an embodiment of the measuring device, the prevention of rotation can be ensured by a laterally displaceable member of the clamping device.

[0034] It is also possible to provide a rod transport device which is configured to grip the section of the material to be straightened to be separated before the cutting operation is performed, transport it to the measuring device after it has been separated from the remaining part of the material to be straightened, insert or place it there in an unchanging rotational position, and release it after the rod-shaped section has been accommodated in the measuring device against rotation.

[0035] As already mentioned above, the measuring unit can be configured so that it can measure the material to be straightened in the rotational position in which it passed through the straightening system. However, this is not necessarily the case, so that it is also possible that the rotational position of the bar section during measurement differs from the rotational position of the bar section at the time of separation from the remaining material. In general, it is sufficient if the bar section is accommodated in the measuring unit so that it can be measured in a defined rotational position that is in a known spatial relationship to the rotational position in which the material to be straightened passed through the straightening system. In that case, straightening-plane-specific measurements can be performed, since the measurement results can be associated with the respective straightening planes.

[0036] Many embodiments of the measuring method utilize this possibility by forming rotational position markings on the bar section, which are suitable for determining the rotational position of the bar section present during straightening. The bar section with the rotational position markings is then transferred to the measuring unit and placed in a defined rotational position in the measuring position of the measuring unit. This rotational position is in a known spatial relationship to the rotational position in which the straightened material passed through the straightening system, so that a conversion or coordinate transformation is possible. In order to be able to systematically and reliably adjust this defined rotational position, a rotational position adjustment assistant is used on the side of the measuring unit, which is designed to functionally cooperate with the rotational position markings on the bar section to ensure that the bar section is placed in a defined rotational position for measurement. The measurement results obtained in this way can then be unambiguously associated with the straightening plane.

[0037] There are various possibilities for generating the rotational position marking. In many embodiments, a bent or curved section is formed at or near the end of the rod-shaped section, which is angled in a predetermined direction to be radial with respect to the longitudinal axis of the rod-shaped section, thereby allowing the rotational position to be precisely determined and possibly reproduced. The length of the curved section compared to the rest of the rod-shaped section is usually quite short, for example at most 20%, or at most 10% of the total length of the rod-shaped section. For the purposes of this application, a rod or "rod-shaped section" does not exist only if it extends substantially straight over its entire length. Rather, a rod or rod-shaped section exists even if it extends straight over the overwhelming part of its entire length, for example at least 80% or at least 90% of its entire length.

[0038] To generate the rotational position markings, notches or other partially dug structures can be formed in the material of the section, for example by using a punch, a center punch, a knurling tool or a tool for imprinting a texture. Cutting tools can also be used for marking by slightly guiding the working stroke and penetrating the blade a little into the material to form the notch. If the material is an insulated wire, the rotational position markings can also be provided by partially or completely removing the insulating layer at small points on its periphery, so that the removed points can be used to recognize the rotational position. In principle, it is possible to use each marking, whose marked points do not have rotational symmetry with respect to the longitudinal axis of the bar-shaped section. For example, it is also possible to design the cutting device in such a way that the cutting operation for separating the bar-shaped sections produces a chamfer at the end of the bar-shaped section, for example on one side, thereby producing a characteristic shape change that is used as a rotational position marking. If chamfers are to be produced on more than one side, the chamfers can be differentiated in such a way that a chamfer that is reliably distinguishable from the other sides can be used as a rotational position marking.

[0039] It is also possible to provide a rotational position marking by means of a laser beam or by providing a color marking or by gluing a preferably self-adhesive sticker on the side of the bar-shaped section. In contrast to the possibilities listed above, which change the shape of the bar-shaped section by mechanical action on the ends, marking by laser (laser marking) or marking or gluing by color is also a possibility of marking the bar-shaped section without mechanical loading of it.

[0040] As a rotational position marking, it is also possible to use a separately formed, preferably shape-fitted, asymmetrical marking element, which can be fixed, for example, by attaching, clipping, clamping, gluing, etc., to the free end before it is separated from the rest of the straightened material. For example, a clip or a small cap formed by 3D printing can be attached, capped or clipped onto the free end before the rod is separated. Due to the asymmetry, the rotational position can then be easily recognized.

[0041] A rotational position adjustment aid can be provided on the side of the measuring unit, which, in accordance with the type of rotational position marking, can functionally cooperate with the rotational position marking to ensure that the bar section is positioned in a defined rotational position oriented for the measurement. In a simple case, the measuring unit itself can be provided with markings or other orientation aids, so that a machine operator or a robot can optically detect in which rotational position the bar section must be mounted in order to be able to perform a directed measurement. It is also possible for the rotational position recognition device to have a camera for optically detecting the rotational position markings. Using the camera signal, the bar section can then be positioned in the measuring unit in a defined rotational position oriented. This correct position orientation can be performed by the operator or semi-automatically or automatically.

[0042] Another possibility is to provide a rotational position recognition aid, which has a mechanical marking counter element for mechanically contacting the rotational position marking of the bar-shaped section. The marking counter element can, for example, have a section with a complementary counter structure to the rotational position marking, whereby the desired rotational position of the bar-shaped section can be adjusted by forming the contact itself. A counter element can be provided which corresponds to the rotational position marking of the bar-shaped section. For example, a locking element can be provided which fits into a notch or a center punch provided at one point on the periphery of the bar-shaped section and serves as a rotational position marking. In order to obtain the defined rotational position, it may be necessary to insert a folded or bent section into a corresponding cutout at the end of the bar-shaped section, or a marking (for example a chamfer) formed by a cutting operation must be applied to the corresponding oblique surface.

[0043] Using the above-mentioned measures, it is also possible, if necessary, to carry out an in-process measurement / closed-loop control, by feeding the straightened bars, regularly or irregularly during the production process according to a predetermined diagram or on a machine-by-machine basis, to a measuring device, where they are measured, thereby determining the straightening quality and, if necessary, making compensating changes to adjust the straightening system. Bars removed from the material stream for inspection purposes can, if possible, be fed again into a subsequent production step, but this is not mandatory. Thus, from time to time, the straightened bars can be separated from the material stream for measurement purposes and, if necessary, returned to the material stream again after the measurement is completed.

[0044] According to a further development, the straightened workpiece is fixed for measurement purposes at a first fastening point and at a second fastening point at a distance from the first fastening point such that for each of the fastening points the vertical and lateral positions of the workpiece (e.g. horizontal direction transverse to the longitudinal axis of the rod) are determined and no forces other than gravity are applied to the workpiece section located between the fastening points. The position of the workpiece is then measured in a measurement plane located between the first and second fastening points. This can be located, for example, in the middle of the fastening points. The residual curvature of the wire section located between the fastening points is then determined using position data for the first fastening point, the second fastening point and the position of the workpiece in the measurement plane.

[0045] Structurally, the measuring device can be provided with first and second clamping devices which provide a rest for the workpiece to be straightened at the appropriate fastening points and have laterally movable clamping members which can be moved into contact with the workpiece to be straightened and thereby determine the lateral position. The clamping members exert only a small force in any case when they come into contact with the workpiece to be straightened.

[0046] According to a further development, the measuring device has a first clamping device on the side facing or to be faced with the cutting device (entrance side) and a second clamping device at a longitudinal distance therefrom, with components of a measuring system arranged in the area between the clamping devices, which measuring system is designed to define a measuring plane oriented transversely, in particular perpendicularly, to the longitudinal direction of the measuring device and to determine the position of the rod-like section placed in the measuring plane. The measuring plane is preferably located in the center between the clamping devices, where typically the largest quantitative displacement of the clamped rod-like section can be expected, which contributes to the measurement accuracy.

[0047] According to a further development, each clamping device has a mounting roller mounted with a horizontal axis of rotation and two lateral positioning elements displaceable by a drive, the inserted bar-shaped sections being respectively fixable at vertically and horizontally defined fixing points. The section lying above the jacket surface of the mounting roller then defines the vertical position, while the laterally positioned lateral positioning elements define the horizontal position. The lateral positioning elements can be formed, for example, as rotatably supported lateral positioning rollers. However, in many cases, rotatability is not necessary. Other fixedly mounted lateral positioning elements, for example lateral positioning blocks, can also be provided, which optionally have a convexly curved front surface in order to provide a point-like or line-like contact surface for the workpiece to be straightened.

[0048] In this type of embodiment of the measuring device, the anti-rotation is ensured by transverse positioning elements of the clamping device, for example in the form of transverse positioning rollers or transverse positioning blocks, which can slide laterally and therefore act as anti-rotation devices. If the rod-shaped section is softly clamped laterally, for example at the vertical axis of rotation by the transverse positioning elements or at the cylindrical front surface by the transverse positioning blocks, the degree of freedom of rotation about the longitudinal axis of the rod is essentially eliminated, while the horizontal clamping between the essentially point-like contact points between the resting rollers and the outside of the rod-shaped section does not essentially prevent any possible sagging of the rod or any vertical displacement. Thus, the true state of curvature of a rod-shaped section, which is supported at two points spaced apart from one another and is otherwise essentially subjected only to gravity, can be measured. Instead of roller-shaped transverse positioning elements, other, possibly immovably supported transverse positioning elements, for example blocks with convexly curved contact surfaces, can also be provided. Preferably, the contact surface against the workpiece must be capable of being formed in such a way that only substantially point-like or small-area contact points occur, so that the straightened bar is clamped between the substantially point-like contact points only in the horizontal direction, whereby any possible vertical sagging is not essentially prevented.

[0049] The anti-rotation can therefore be an element with a suitable geometry that allows point or line contact between the clamping device and the rod-like section, for example the rollers mentioned, but also non-rotatable elements that have sharp edges or rounded edges at least in the contact area, thus for example cylindrically or spherically curved contact surfaces.

[0050] According to a further development, the distance between the clamping devices, measured parallel to the longitudinal direction, is infinitely adjustable, so that the measuring device can be easily adapted to bar sections of various lengths. The bar sections provided for measurement are often much shorter than one meter, their length depending on the stiffness of the straightened material, for example between 300 mm and 700 mm, and in some cases (in the case of relatively thin bar materials) even less.

[0051] One of the clamping devices can be fixedly mounted, only the other one slidable, but preferably the clamping devices are mounted on a carriage which runs on a guide rail which is fixed to the upper side of the horizontally oriented base plate of the measuring system, so that the two clamping devices can slide infinitely in the same axis and then be fixed in the desired position.

[0052] In order to be able to position the measuring plane well for rods of different lengths, according to a further development, the components of the measuring device are fixed to a support which is mounted on a carriage which can run on guide rails which also guide the clamping device, thus forming an arrangement which is very stable and which can be easily adapted to the various dimensions of the rod-like sections to be measured.

[0053] For the measurement recording, i.e. measurement, of the straightened material after it has passed through the straightening system, in principle any measuring device can be used which provides a quantitative description of the residual curvature in the straightening plane of the roller straightener and allows an unambiguous correspondence of the measured residual curvature to the straightening plane.

[0054] The measured quantity does not have to directly correspond to the residual curvature, it is sufficient if the measured quantity is a value which represents the residual curvature. The measurement can be performed tactilely (and therefore with contact) or without contact, for example with optical and / or electromagnetic devices. What is important in that case is that the measurement technique allows a description of the residual curvature or the straightening quality in the straightening plane in which the respective straightener acts, in order to adjust the straightener.

[0055] According to a further development, the measuring device has an optical measuring system which generates two mutually perpendicular laser light curtains located in the measuring plane by means of laser radiation and detects them by means of opposite photosensitive sensors, so that the position of the workpiece in the measuring plane can be determined with high precision in two directions by projection. The non-contact measurement does not affect the shape of the bar to be measured.

[0056] The residual curvature, which is present in the curvature plane (plane perpendicular to the rotation axis of the straightening rollers) affected by the respective roller straightener, can be easily determined from the distance between the measured position of the bar section, which is present in the measurement plane, and a reference position, which is located in the measurement plane, which would be present if the straightened material had the desired residual curvature. This reference position takes into account the sag of the straightened material, which is preferably not on a straight line connecting the two fixing points, but rests on the fixing points, which is present due to gravity. To determine the position of this reference point, the straightened material parameters used for the sensitivity analysis can likewise be used, possibly modified according to the situation in which the straightened material is deformed several times in the straightening process and thus possibly changed in terms of its elastic properties.

[0057] The invention also relates to a method for adjusting a straightening system for straightening a passing wire- or tube-shaped workpiece, in which a measuring device and a measuring method according to the claimed invention are used.

[0058] Further advantages and aspects of the invention will become apparent from the claims and from the following description of embodiments of the invention, which are illustrated in the following figures. [Brief description of the drawings]

[0059] [Figure 1] FIG. 1 shows the components of a feeding apparatus for feeding wire material from a wire coil to a deformation machine (not shown), the feeding apparatus being located at a conditioning station with an integrated straightness measurement system. [Diagram 2] FIG. 2 shows an enlarged view of the straightening system of the feeding device shown in FIG. [Diagram 3] FIG. 3 shows an enlarged view of the measuring device of the conditioning station shown in FIG. [Figure 3A] FIG. 3A shows the measurement plane in detail. [Figure 4A] FIG. 4A shows a method variant in which self-rotation of the separated and straightened round bar during measurement separated from the rest of the wire is prevented by an anti-rotation device. [Figure 4B] FIG. 4B shows a method variant in which the self-rotation of the separated and straightened round bar during measurement separated from the rest of the wire is prevented by an anti-rotation device. [Figure 4C] FIG. 4C shows a method variant in which the self-rotation of the separated and straightened round bar during measurement separated from the rest of the wire is prevented by an anti-rotation device. [Figure 5A] FIG. 5A shows a method variant in which the straightened bar is separated from the flat material and measured. [Figure 5B] FIG. 5B shows a method variant in which the straightened bar is separated from the flat material and measured. [Figure 5C] FIG. 5C shows a method variant in which the straightened bar is separated from the flat material and measured. [Figure 5D] FIG. 5D shows a method variant in which the straightened bar is separated from the flat material and measured. [Figure 6A] FIG. 6A shows an embodiment with a device for generating the rotational position marking on the side of the supply device and a rotational position adjustment aid on the side of the measuring unit. [Figure 6B] FIG. 6B shows an embodiment with a device for generating the rotational position marking on the side of the supply device and a rotational position adjustment aid on the side of the measuring unit. [Figure 6C] FIG. 6C shows an embodiment with a device for generating the rotational position marking on the side of the supply device and a rotational position adjustment aid on the side of the measuring unit. [Figure 6D] FIG. 6D shows an embodiment with a device for generating rotational position markings on the side of the supply device and a rotational position adjustment aid on the side of the measuring unit. [Figure 6E] FIG. 6E shows an embodiment with a device for generating a rotational position marking on the side of the supply device and a rotational position adjustment aid on the side of the measuring unit. [Figure 7A] FIG. 7A shows an embodiment with a device for generating the rotational position marking on the side of the supply device and a rotational position adjustment aid on the side of the measuring unit. [Figure 7B] FIG. 7B shows an embodiment with a device for generating the rotational position marking on the side of the supply device and a rotational position adjustment aid on the side of the measuring unit. [Figure 7C] FIG. 7C shows an embodiment with a device for generating the rotational position marking on the side of the supply device and a rotational position adjustment aid on the side of the measuring unit. [Figure 8A] FIG. 8A shows an embodiment with a device for generating a rotational position marking on the side of the supply device and a rotational position adjustment aid on the side of the measuring unit. [Figure 8B] FIG. 8B shows an embodiment with a device for generating the rotational position marking on the side of the supply device and a rotational position adjustment aid on the side of the measuring unit. [Figure 9]FIG. 9 shows an embodiment with a device for generating the rotational position marking on the side of the supply device and a rotational position adjustment aid on the side of the measuring unit. [Figure 10] FIG. 10 shows another embodiment of a measuring device for measuring the residual curvature in a straightened and separated bar. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0060] Below, examples of measuring units and methods are described for measuring the residual curvature of a straightened wire or pipe-shaped workpiece. The workpiece passes through a straightening system with two successively connected roller straighteners with straightening planes oriented perpendicular to each other. The workpiece, e.g. a wire, can be further processed in a deformation machine to form straight or curved shaped parts from the straightened workpiece. The measuring units and methods can be used, for example, when adjusting the straightening system.

[0061] FIG. 1 shows the components of a wire processing installation, which is designed and adapted to process elongated workpieces 110 in the form of metal wire, which are provided as a workpiece stock in the form of so-called coils, and thus wire bundles wound in the form of reels. From the workpiece material, which is initially present in large lengths on the workpiece stock, a more or less large number of homogeneous or non-homogenous shaped parts are formed by deformation in a computer numerically controlled manufacturing process. The shaped parts can be, for example, coil springs, in particular compression or tension springs, or bent parts of other geometric arrangements. The shaped parts can generally be bent in two or three dimensions, and can also be present in the form of straight bars, for example in straightening machines or bar mass production machines. The Cartesian xyz machine coordinate system is used to better describe the orientations and positional relationships.

[0062] In the ready-to-operate state, the wire processing installation comprises a deformation machine (not shown), which can be designed, for example, as a spring winding machine in the case of forming coil springs.

[0063] Further, there is provided an apparatus 300 for feeding the elongated wire-shaped workpiece material to a deformation machine, also referred to in the present application as a feeding apparatus 300 for short. The feeding apparatus is a deformation machine which produces a straightened wire by deformation from a more or less strongly curved wire of a wound wire stock. Figure 1 shows some components of the feeding apparatus 300 at a conditioning location or station 350.

[0064] The task of the feeding device 300 is to feed the downstream connected deformation machine or its withdrawal device with a straightened wire shape (residual curvature is almost zero within the tolerance range) at each point in time as accurately as possible at the speed required at that point in time. The feeding device 300 has a dedicated control unit 390, which communicates with the control unit of the deformation machine. The functionality of the two control units can be integrated in a single control unit.

[0065] After completion of the adjustment at the adjustment station, the supply device is moved to its working position in the transformation machine to be supplied, for which purpose the components shown are mounted on a movable platform, which can be linearly slidable, for example on guide rails, or rotatably supported about a vertical axis of rotation, or can be movable unguided (for example on rollers or wheels).

[0066] The feeding device comprises a feeding unit 310 with a receiving device 330 for receiving a workpiece stock 381 in the form of a coil and a downstream straightening system 400 for straightening the workpieces before they enter the transforming machine. The straightening system 400 is shown in detail in FIG.

[0067] FIG. 1 shows the feeding unit 310 in the adjustment station 350, which allows the machine operator to carry out all operations in the straightening system 400 in the adjustment station 350, which are necessary to adjust the straightening system to the workpiece material used and to feed straightened workpiece material with a high straightening quality, in particular material without residual curvature or with only a slight residual curvature within the tolerance range, when the feeding unit is in the production drive and therefore in its working position in the deformation machine.

[0068] The workpiece stock (coil) is pre-held on an exchangeable reel 335, which is received by the receiving device 330 and supported for rotation about a horizontal axis of rotation in the received state. In this case, the support does not take place in the area of ​​the axis of rotation of the reel, but instead two axially parallel support rollers 332, 333 with a horizontal axis of rotation in the floor area are mounted. These support rollers are part of the receiving device 330. The reel is placed on the two support rollers, so that the circumference of the disk-shaped side members of the reel rests on the two support rollers and the position of the axis of rotation in space is determined. In the example case, the reel is an active reel with a dedicated drive. A drive 334 engages the front support roller 333 and can drive it under the control of a control unit 390.

[0069] The drawn wire is guided through a deflection device 340, which has an upper deflection roller 340-1 and a lower deflection roller 340-2, which are rotatably supported on a vertical support 341 with parallel axes. The upper deflection roller is configured as an active dancer roller with spring return. By referencing the position of this roller, the drive motor for the support / drive roller is controlled in a closed loop. The lower deflection roller is wound, for example, over three-quarters of its circumference, so that the outlet, and therefore the upper side of the lower deflection roller 340, is at the height of the passage opening on the inlet side of the straightening system 400.

[0070] The wire is thus guided substantially horizontally by the lower deflection rollers to the straightening system 400. Between the deflection device and the straightening system there is a wire guiding device 375, the outlet of which is aligned with the inlet of the downstream connected straightening system 400. A wire end recognition device can be integrated into the wire guiding device.

[0071] An alternative construction is shown or suggested in FIG. 1 by dashed lines. In this construction, the lower deflection roller is omitted. This construction has a buffer store 600 in the form of a storage box that is relatively flat and open on one side (here towards the top) and a leading-stage connected auxiliary draw-in device 610, which can be arranged behind the upper deflection roller 340-1. The auxiliary draw-in device can be driven by an auxiliary drive and is configured to transfer the workpiece, and thus the wire in this example, to the leading-stage connected buffer store 600 at a predeterminable transport speed. The buffer store has an inlet and an outlet for the workpiece. The buffer store is designed in such a way that the workpiece in the buffer store can form a workpiece loop 111 of variable length between the inlet and the outlet. Speed ​​differences between the areas in front and behind the buffer store can thus be compensated. A sensor system is preferably provided for detecting the degree of filling of the buffer store and for generating a sensor signal representative of the degree of filling. The control device can then be configured such that the transport speed of the auxiliary retraction device is controllable or controlled according to the sensor signal of the sensor system. The buffer reservoir can also be integrated horizontally if necessary, so that the workpiece loop is formed in a substantially horizontally oriented plane. For further details and variants, reference is made to WO 2020 / 224977 A1, the disclosure content of which about the feeding device is incorporated herein by reference.

[0072] The straightening system 400 comprises two roller straighteners 400-1, 400-2, which are arranged directly behind one another and can be adjusted independently of one another, each having a certain number of axially parallel straightening rollers. Here, seven straightening rollers are provided in each case, but other numbers are also possible, for example from 5 to 9. The rotation axes of the straightening rollers of the straighteners connected behind one another are oriented perpendicular to one another.

[0073] In the roller straightener, the straightening roller is adjusted eccentrically with respect to the neutral axis of the material to be straightened, so as to generate a variable curvature, which deforms the material to be straightened into the plastic region and thus straightens it. In contrast to the roller straightening machine, the straightening roller is here passive, i.e. is not driven in rotation, so that there is no drive for rotating the straightening roller. The wire is pulled through the roller straightener. For this purpose, a drawing device 385 is provided, which is arranged behind the straightening system 400 in the material flow direction and is used in particular to draw the wire material through the two roller straighteners 400-1, 400-2 of the straightening system 300 in the direction of the subsequent components.

[0074] The components of the straightening system 400 are supported by a frame part in which the control unit 390 of the supply unit 310 can also be accommodated. This frame part also supports a retraction device 385, which in the example is formed as a drum retraction device, and which can also be formed as a belt retraction device or a pliers-type retraction device in other embodiments. Behind the retraction device 385 in the material flow direction, an optional, possibly manually operable clip device can be provided, by means of which the axial position of the passing wire can be fixed if necessary.

[0075] Further details are given by way of example of a first roller straightener 400-1, effective in a vertical plane (xz-plane), shown enlarged in FIG.

[0076] The first roller straightener 400-1 has seven passive straightening rollers R1, ... R7 with horizontal rotation axes parallel to one another, which are arranged alternately on opposite sides of the passing section (parallel to the x-axis) in the passing direction 115. These straightening rollers define the effective straightening geometry of the roller straightener by their circumferential sections which are in contact with the material to be straightened 110 during the operation of the straightening system. The first roller straightener 400-1 changes the curvature substantially only in the vertical plane of the straightening plane (xz-plane). The second roller straightener 400-2, which is responsible for straightening in the horizontal plane, is constructed similarly, where the straightening roller rotation axes run vertically.

[0077] In the example case, all seven straightening rollers are designed as automatically deliverable straightening rollers and can be delivered automatically, independently of one another, in both directions in a delivery direction oriented perpendicular to the pass direction (parallel to the z-axis) by servo motor drives 405-1, ... 405-7 in response to control signals from the control unit 390.

[0078] There are also variants in which all straightening rollers are manually adjustable. For this purpose, for example, adjustment screws and position indicators can be provided. There are also examples in which some straightening rollers (for example 2, 3 or 4) are automatically adjustable and some others (for example 3, 4 or 5) are manually adjustable.

[0079] Due to the large number of adjustment degrees of freedom, a correct adjustment of the roller straightener requires an experienced machine operator, and the adjustment operations or adjustments in each case require a great deal of time.

[0080] The adjustment station 350 or the conditioning station 350 has a cutting device 370 by means of which the straightened rod-shaped wire section 110-A is cut off as a sample from the supplied wire in the course of the adjustment operation in the straightening system and is thereby prepared for the straightness test. In the example, an automated cutting device 370 is provided, alternatively a manually operable cutting device can be provided. Furthermore, the adjustment station 350 has a measuring device 500.

[0081] The wire sections or wire rods 110-A separated by the cutting device are checked for straightness or residual curvature by a downstream measuring device 500. In this case, the anti-rotation device ensures that the rotational position of the material rod provided for measurement about its longitudinal axis does not change, so that the wire is measured in its rotational position in which it has passed through the straightening system.

[0082] The measuring device 500 and the associated cutting device 370 are components of a measuring unit 350, which, possibly together with other components, forms a self-contained unit which can be used as the conditioning station 350. The same reference number 350 is therefore used for the conditioning station and the measuring unit.

[0083] FIG. 3 shows an enlarged view of the components of the measuring device 500 in detail. The measuring device 500 has a first clamping device 510-1 on the side facing the cutting device 370 and a second clamping device 510-2 at a distance behind it. The clamping devices are mounted on a carriage which runs on two guide rails 501 which are fixed on a horizontally oriented base plate 502. The axial distance between the clamping devices, measured parallel to the passing direction, can therefore be adjusted steplessly. Each clamping device has a mounting roller 512-1, 512-2 mounted with a horizontal axis of rotation and two pneumatically displaceable lateral positioning rollers 514-1, 514-2. The inserted wire rod can therefore be fixed at a precisely defined fixing point both vertically and horizontally. The rollers contact the wire without the introduction of any other force or torque, so that the wire rod rests in a defined fixed position at the front and back and is subjected only to gravity between them during actuation. The rod cannot rotate about its axis when it is softly clamped between the horizontally slidable rollers 514-1, 514-2.

[0084] In the area between the clamping devices 510-1, 510-2, the components of the measuring system 520 are mounted. They are supported by a cross-shaped support 522, which is mounted on a carriage that can run on guide rails 501, which also guide the clamping devices. The measuring system 520 is an optical measuring system that can determine very accurately the position of the wire placed in a measuring plane 524 oriented perpendicular to the x-direction. Above the straight coupling line between the fixing points, a second laser unit 525-2 is mounted, which generates a laser light curtain located in the measuring plane 524, which enters the detection area of ​​a photosensitive sensor 527-2 on the opposite side, so that the position of the wire in the lateral (horizontal) direction in the projection can be accurately detected. The vertical position is detected by the first laser unit 525-1 and the opposite sensor 527-1. The measurement is preferably performed horizontally or vertically with two lasers, centered between the two fixtures.

[0085] The enlarged detail of Fig. 3A shows a typical measurement situation, where the plus sign indicates the intersection of the connecting line between the fixing point and the measurement plane 524. The hatched circle represents the position of the wire section 110-A in the center between the clamping devices. From the horizontal distance value ΔH and the vertical distance value ΔV, the residual curvature of the wire rod in the respective straightening plane can be calculated. The results are therefore straightening plane specific and are evaluated accordingly to provide indications for the improvement of the straightening geometry, possibly determined separately for each of the two roller straighteners.

[0086] When evaluating, it is taken into account that the wire rod brings about a certain sag solely due to gravity, the extent of which depends on the material characteristic value and the distance between the fixing points. This amount is excluded from the calculation when evaluating. As a result of the measurement, a quantitative value for the residual curvature is generated, which may also have a contribution in the horizontal and vertical directions. Based on these measurements, the straightening geometry of the roller straightener must then be adjusted so that in the next wire piece the residual curvature disappears.

[0087] The inventor sees a potential problem when processing round material, where a round bar that still has a significant bulge in the horizontal plane after straightening can roll of its own accord into a stable rotational position when inserted into the measuring device, where the bulge can sag downwards, which will impersonate a bulge in the vertical direction that does not actually exist, thereby resulting in erroneous measurement results and consequently erroneous delivery and / or erroneous delivery in the wrong straightener.

[0088] In order to ensure that the measurement results can be accurately assigned (horizontally and vertically) to different straightening planes or roller straighteners, special measures are, if necessary, taken to ensure that the wire rod provided for the measurement cannot rotate about its longitudinal axis while being measured separated from the rest of the workpiece to be straightened. For this purpose, the measuring system is designed for straightening-plane-specific or straightening-plane-selective measurements.

[0089] The method variants shown diagrammatically in Figures 4A to 4C are suitable for many materials of various cross-sectional shapes, in particular also for round materials. In that case, the front end section 112 of the workpiece to be straightened, which is continuous with the front side 113, is first transferred by controlled feed (by the retraction device 385 connected to the front stage) to the measuring position in the measuring device 500 (Figure 4A), then it is contacted on diametrically opposite sides by the laterally slidable rollers 514-1 or 514-2 of the clamping devices 510-1, 510-2, thereby clamping horizontally and thus preventing rotation (Figure 4B), and only then is the bar to be measured separated from the remaining part of the workpiece to be straightened (Figure 4C). Then the measurement is started by the optical measuring system 520.

[0090] The horizontally runnable rollers 514-1 or 514-2 of the clamping device act as anti-rotation devices and contact the wire material at two diametrically opposed contact points in the horizontal direction with a relatively low pressure which is determined so that adhesive friction is sufficient to prevent self-rotation of the rod about its longitudinal axis, but at the same time the wire rod is allowed to relax with no forces other than gravity applied, thus exhibiting the residual curvature to be measured.

[0091] 5A to 5D, another method variant for checking the straightness of a rod by means of a measuring device is described. First, a wire with a flat rectangular cross section (see details) is fed to the cutting position by wire feed by the retraction device 385. This is characterized in particular in that the front end 113 of the rod has already reached the rest roller of the rear or second clamping device 510-2 and is resting there. During this insertion operation, the lateral positioning roller is in its retracted position. Then, the cutting by the cutting device 370 takes place (FIG. 5B). In the next method step (FIG. 5C), the cut wire piece is moved further forward to its measuring position, where the wire rod is centered with respect to the central measuring plane so that on both sides a piece of equal length extends beyond the rest roller. For this short wire feed, no special devices are required. Rather, the following wire piece arrives at the rear front end of the wire rod to be measured by the retraction device 385, which can result in a horizontal feed in the form of a shove. In the next step (FIG. 5D), the lateral positioning roller is moved in the direction of the fixed position defined by its pneumatic cylinder. Furthermore, the wire piece is pressed against the rear stop, which ensures the defined plane. The wire rod is thus fixed for the measurement. It can be clearly seen that the connecting line between the front and rear fixed positions does not have to be coaxial with the feed axis of the subsequent wire.

[0092] The preferred measuring device and method are described by way of example on the adjustment of a deformation machine in the form of a feeder which, in normal use, by means of an integrated straightening system, forms a straightened wire material from the wire material arriving with a variable input curvature, fed from a coil, which wire material is fed as "endless material" to a downstream connected deformation machine.

[0093] The straightening system can have exactly two roller straighteners, which preferably form a straightening plane perpendicular to each other. The straightening system can also have three, four or even a larger number of roller straighteners. For example, the straightening system can have four straighteners, each displaced by 45°, which can be a preferred variant, for example, for straightening round wires.

[0094] The deformation machine integrated in the straightening system may be a straightening and cutting machine, which is designed to straighten wires or other semi-finished materials that can be processed by straightening, having various cross-sectional sizes and shapes, and to subsequently separate the straightened material to the desired length. In that case, the machine further comprises a length measuring device and a cutting device, which can preferably be operated automatically on the basis of a signal from the length measuring device. A measuring unit can then measure the separated and straightened rods, which does not require a dedicated cutting device for that purpose. It may also be a rod mass production machine, which, in addition to the straightening system, the cutting device and the length measuring device, further comprises an insulation removal device, by means of which sections of insulation are removed from the metallic initial material coated with an insulating layer.

[0095] The straightening system can also be integrated into a deformation machine, which can form smaller or larger series of shaped parts, partly with complex geometries, in an automated production process from the straightened material by means of suitable deformation tools. The deformation tools required for the deformation are then connected downstream of the straightening system. The deformation machine can be, for example, a bending machine for forming bent parts from wire, band or pipe material, or a spring forming machine or a wire nail machine for the mass production of screws, nails, rivets, etc.

[0096] The invention can be used for various types of straightened material, in particular for straightening metal wire or pipe material. The cross-sectional shape of the straightened material can be various, for example a circular cross-section in round material, a concave and / or polygonal cross-section in profile material, a rectangular cross-section in particular in square material. Flat materials can also be straightened, for example flat bands of metal with a large aspect ratio between width and height. The cross-sectional size can also vary. Metal materials can be uncoated or have a coating, for example an insulating layer made of an electrically non-conductive plastic.

[0097] The linearity check or linearity measurement does not have to be performed as described in the examples. The linearity check can also be performed automatically with at least one camera. For example, in the case of flat materials, the linearity can be checked during the pass by two cameras, for example displaced by 90°. In the case of particularly round wires, a camera rotating around the wire or a laser scanner can be used.

[0098] 6 to 9, various embodiments are described, each with a device for generating a rotational position marking on the side of the feed unit and a rotational position adjustment auxiliary device on the side of the measuring unit. A rotational position marking can thus be generated on the bar section on the side of the feed unit, which allows an unambiguous determination of the rotational or spatial position in which the bar section has been straightened. On the side of the measuring unit, a rotational position adjustment auxiliary device adapted thereto is provided, which cooperates functionally with the rotational position marking on the bar section and can accommodate the bar section in a defined rotational position into the measuring unit, so that the measured values ​​determined by the measuring unit can be unambiguously related to the rotational position in which the bar section passed through the straightening system. The transport of the bar section between the feed unit and the measuring unit can be performed manually, semi-automatically or automatically, without the need to maintain a defined rotational position or orientation of the bar section during the entire transport. For example, an operator can grasp the marked rod section after it has been separated from the wire, insert it into a measuring unit, and use the rotational position markings and a matching rotational position adjustment aid to insert the wire into the measuring unit in the correct rotational position.

[0099] 6A to 6D show the area of ​​a retraction device 385 and a downstream connected cutting device 370 in one embodiment at various stages of producing a rotational position marking on a bar-shaped section 110-A of the material to be straightened 110. The material to be straightened is assumed here to be a round wire. FIG. 6A shows the cutting tool before it penetrates into the wire during the cutting operation. FIG. 6B shows the retraction movement of the cutting tool after the wire has been separated. A bar-shaped section has been separated by cutting and the next one is about to be formed. After separation of the resulting bar-shaped section, the wire is fed a short distance, for example a few centimeters, by the retraction device 385. The upper cutting tool 370-1 then imprints or makes a V-shaped notch 115-1 in the upper side of the wire a short distance from the front end in a notching operation (FIG. 6C). After retraction of the cutting tool 370-1 used for notching, the rotational position marking 115-1 formed by the notch 115-1 can be seen on the upper side of the wire. The wire (material to be straightened) is then fed a distance until the next separation point is within the area of ​​the cutting device 370. The bar-shaped section 110-A marked by the notch 115-1 is then separated.

[0100] Since the wire is still suspended on the supplied wire when forming the notch 115-1 (FIG. 6C), the bottom of the V-shaped notch runs parallel to the horizontal direction, the notch is on the upper side, and the vertical direction is discernible from it. Therefore, by using the notch 115-1, it is possible to unequivocally confirm in which rotational position the wire was in during the straightening.

[0101] FIG. 6E shows the insertion of the rod section 110-A into the measuring device 500 in the appropriate orientation or rotational position, which can be determined using the notches 115-1 or the rotational position markings. The rod section 110-A is placed on the rest rollers 512-1, 512-2 in such a way that the rod end with the markings 115-1 is behind the rear rest roller 512-2. The measuring unit then has a rotational position adjustment aid 550 with a downwardly facing wedge 555, whose V-shape corresponds to the shape of the edge of the cutting tool 370-1. The wire can thus be oriented exactly as it passed through the straightening unit using the markings on the wire and the appropriate cutouts in the measuring station. The curvature components represented by the measurement data can thus be unambiguously associated with the different straightening planes of the roller straightener (straightening plane-specific measurements).

[0102] Whereas in the variant of Fig. 6 a separate cutting operation is provided after the wire feed to generate the notch 115-1 used as a rotational position marking, in the variant of Figs. 7A to 7C the rotational position marking is formed during the cutting operation. The cutting device here has an upper cutting tool 370-1 with a bevel on one side, which cooperates with a lower non-cutting cutting tool as a counterholder. Since the cutting movement is performed only from one side, at the end of the wire there arises a beveled chamfer 115-2 provided as a rotational position marking, the orientation of which allows the rotational position of the wire during cutting to be clearly defined.

[0103] In the corresponding measuring unit, beyond the second rest roller, there is a rotational position adjustment aid 550, which has a vertically movable stop which at its lower end has a bevel which corresponds to the bevel on the cutting wedge of the cutting tool. The bar section is inserted so that the chamfer 115-2 on the front side of the bar section 110-A rests flat against this stop. Correct orientation is thus determined by mechanical contact with this bevel. The stop is then moved out of engagement with the bar section, so that contact with the stop does not impair the measurement.

[0104] In the embodiment of Fig. 8, after separation of the preceding bar section, a short piece of wire is bent at the front end of the next bar section 110-A by approximately 90°, so that a short end piece 115-3 of the bar section projects radially parallel to the vertical plane. This bend or radially projecting end piece 115-3 serves as a rotational position marking and is provided here, for example, by the cutting tool 370-1 itself, after separation of the preceding bar section. Alternatively, other bending tools are possible.

[0105] The measuring device 500 (FIG. 8B) is provided with a rotational position adjustment aid 550 having a marking counter-member corresponding to the bend 115-3, which marking counter-member has a cut-out 556 into which the bend fits. The bar section 110-A is inserted into the measuring device such that the bent end piece fits into the cut-out. For measurement, the marking counter-member is moved downwards so that the cut-out is out of engagement with the bar section and no force is applied to this section for measurement.

[0106] 9 shows diagrammatically an alternative, in which the measuring device rotational position adjustment assistant 550 has a camera 558 by means of which the front end of the inserted bar-shaped section 110-A can be detected. The rotational position markings (e.g. bend 115-3) are thus determined here contact-free by an optical measuring system. Alternatively, a linear laser can also be used as the optical measuring system. The measured values ​​provided by the optical measuring system are then processed in order to determine the rotational position of the bar-shaped section 110-A during the measurement and thereby form a correlation for the orientation of the straightening plane in the straightening unit.

[0107] 10 shows a further embodiment of a measuring device 600, which is designed to measure the finite length of a bar 110-A after it has been straightened and separated from the subsequent straightened material, with respect to any curvature that may be present. The measuring device 600, which is constructed relatively simply and robustly, can be installed at suitable locations in the production hall and can be used by various machine operators to measure the straightened bars from time to time, with respect to any curvature that may be present, and to carry out measurements specific to the straightening plane in that case. The measuring device 600 can be mounted, for example, on a roller wagon, in order to be able to use it in various places, but it is of course also possible to mount it stationarily.

[0108] The measuring device 600 has a relatively heavy, torsion-resistant base plate 605, which can be mounted, for example, on the top of a roller wagon and which supports all other components of the measuring device. The measuring device 600 has a first fixing device 610-1 and, at a distance in the x-direction relative to it, a second measuring device 610-2, which are designed in such a way that the rod to be measured can be accommodated without force in a precisely defined spatial position. This distance in the x-direction is dimensioned to be slightly shorter than the shortest rod to be measured.

[0109] Each fixing device has a bearing block 612-1, 612-2 in the form of a plate standing vertically in the yz-plane. On the upper side of each bearing block, a substantially V-shaped rod receiving section 615-1, 615-2 is formed, which widens upwards. The side surfaces of the rod receiving sections are inclined at an angle of 45° to the xz-plane or the vertical and are formed in a roof shape, so that at the ridge of the roof shape, each rod receiving section forms only a point-like or line-like contact surface with the inserted rod.

[0110] In the example case, a bar 110-A of flat material with a rectangular cross section is measured. The wider side is in line contact with one of the side surfaces, and the narrower side is in line contact with the other side surface near the bottom of the V-shape. This determines and fixes the position of the bar vertically (z direction) and laterally (y direction) to the yz-plane, so that no prescribing forces (apart from gravity) act on the resting bar. Measurements of round materials are possible in exactly the same way, in which in this case point-like contact areas are produced on the inwardly projecting edges of the sides of the bar receptacle.

[0111] On the outside of the bearing block of the first fixing device 610-1 a foldable stopper 640 is provided which makes it possible in a simple manner to insert the rod so that the rod centre is exactly centred between the mounting points of the fixing devices.

[0112] When measuring flat materials, a precisely known relationship usually occurs automatically during loading between the rotational position for the straight cut and the rotational position for the measurement, insofar as they are rotated 45° relative to one another. In the case of round materials, this relationship can be ensured, for example, by means of a rotational position marking (e.g. color marking, attached or clamped marking elements, etc.) and a suitable rotational position recognition device in the measuring device.

[0113] If the straightened rod still has a relatively strong curvature and / or is slightly twisted, for example after the first straightening process, it may not be possible to guarantee that the rod is placed in the two fixing points (front and rear or first and second fixing devices) in the correct position. In order to nevertheless guarantee a reliable measurement, in many embodiments one of the two fixing devices is provided with an additional clamping member, which is designed to grip a section of the rod located in the rod receiving part and press said section against the side of the rod receiving part with a small force. This small force acting only on the end section of the rod makes it possible to guarantee a defined rotational position of the rod in this rod receiving part, without imposing a force on the entire rod which would change the curvature to be measured.

[0114] The actual measurement is performed in a manner similar to the measurement operations already described in the other embodiments. The components of the measuring system 620 are mounted in the center between the clamping devices 610-1, 610-2. The measuring system works optically and determines with high precision the position of the wire or rod placed in the yz-plane (measurement plane) centered between the clamping devices. The electro-optical components of the measuring system (two laser units and the appropriate sensors for the projection measurement) are fixed to a C-shaped support that is open towards the visible front side, thus allowing the rod to be inserted comfortably by hand. In contrast to the variant shown in FIG. 3, the measuring devices are oriented perpendicular to one another, not horizontally and vertically, but inclined at 45° to the horizontal (y-direction). This corresponds to the oblique position of the rod, which is caused by the V-shaped accommodation of the clamping points. The oblique orientation allows the curvature components at the wide and narrow sides, for example when measuring flat materials (as shown in the example), to be detected and evaluated particularly accurately. For further functioning, reference is made to the preceding embodiment.

Claims

1. A measuring unit (350) for measuring the residual curvature of a straightened wire or pipe-shaped workpiece that has passed through a straightening system with two tandemly connected adjustable roller straighteners having differently oriented straightening planes, A measuring device (500) that holds rod-shaped sections (110-A) separated from a straightened material that has passed through a straightening system at a measurement position and obtains measurement data representing a residual curvature of the straightened material, 4. A measuring unit comprising: a roller straightener for straightening a surface of a roller straightener, the roller straightener including a roller straightener for straightening a surface of the roller straightener, the roller straightener being configured for straightening-plane-specific measurements, the measuring unit being configured for straightening-plane-specific measurements, the measuring unit being configured for straightening-plane-specific measurements, the measuring unit being configured for straightening-plane-specific measurements,

2. a device (510, 610) for fixing the rod-shaped section to a first fixing point and a second fixing point at a distance from the first fixing point as follows, i.e., for each of the fixing points only the vertical and horizontal positions of the rod-shaped workpiece are determined, and no force is applied to the section of the rod-shaped workpiece located between the fixing points, except for gravity; a device (520, 620) for measuring the position of the workpiece in a measurement plane (524) located between the first and second fixing points; a device for determining the residual curvature using position data for the position of the workpiece at the first fixation location, the second fixation location and in the measurement plane (524); The measuring unit according to claim 1 .

3. 2. The measuring unit according to claim 1, characterized in that the measuring unit comprises a cutting device (370) for separating rod-shaped sections (110-A) of a predeterminable length from the material to be straightened that has passed through the straightening system, the cutting device (370) being preferably mounted on or to a common frame together with the measuring device (500).

4. The measuring unit according to claim 1 , characterized in that the measuring unit (350) is configured such that the straightened material can be measured at a rotational position where it has passed through the straightening system (400).

5. 2. The measuring unit according to claim 1, characterized in that the anti-rotation device (514-1, 514-2) is configured so that between straightening and measurement, the rotational position of the separated rod-shaped section (110-A) provided for measurement about its longitudinal axis does not change, so that the straightened material can be measured in the rotational position in which it has passed through the straightening system.

6. 4. A control unit (390) according to claim 3, characterized in that in a drive mode, the control unit is configured as follows: the cutting device (370) and the measuring device (500) are driven synchronously, whereby the front end section (112) of the straightened workpiece is transported by controlled feed to a measuring position in the measuring device (500), after which the straightened workpiece is prevented from rotating by anti-rotation devices (514-1, 514-2) of the measuring unit (350), in particular clamped horizontally, and after which the cutting device (370) is driven to separate the bar-shaped section to be measured from the remaining part of the straightened workpiece.

7. The measuring unit (350) comprises a rotational position adjustment assistant (550) configured as follows: to functionally cooperate with rotational position markings (115) provided on the bar-shaped section (110-A) suitable for identifying the rotational position of the bar-shaped section, to ensure that the bar-shaped section can be accommodated in the measuring unit such that the bar-shaped section can be measured in a defined rotational position, which is in a known relationship to the rotational position at which the straightened material passed through the straightening system (400); preferably the rotational position adjustment assistant comprises at least one rotational position recognition device, which is configured to recognize the rotational position markings (115) provided on the bar-shaped section (110-A), which rotational position recognition device is preferably of the following group: a camera (558) for optically detecting said rotational position markings; 2. The measuring unit according to claim 1, characterized in that the measuring unit is selected from: a mechanical marking counter-member for mechanical contact of the rotational position marking (115), the marking counter-member preferably having a section with a complementary counter structure (556) to the rotational position marking, such that the desired rotational position of the rod-shaped section can be adjusted by contact.

8. 2. The measuring unit according to claim 1, characterized in that the measuring device (500) has a first clamping device (510-1) on the inlet side and a second clamping device (510-2) at a longitudinal distance therefrom, the components of the measuring system (520) being arranged in the area between the clamping devices (510-1, 510-2), the measuring system defining a measuring plane (524) oriented transversely, in particular vertically, to the longitudinal direction and designed to determine the position of the rod-shaped section (110-A) placed in said measuring plane (524), preferably each of the clamping devices having one placement roller (512-1, 512-2) mounted with a horizontal axis of rotation and two lateral positioning members displaceable by a drive, in particular lateral positioning rollers (514-1, 514-2) or lateral positioning blocks, in such a way that the inserted rod-shaped section can be fixed at fixing points respectively defined in the vertical and horizontal directions.

9. 9. A measuring unit according to claim 8, characterized in that the spacing of the clamping devices (510-1, 510-2), measured parallel to the longitudinal direction, is steplessly adjustable, preferably the clamping devices are mounted on a carriage, which runs on a guide rail (501) which is fixed to the upper side of a horizontally oriented base plate (502) of the measuring system, and / or the components of the measuring devices are fixed on a support (522), which is mounted on a carriage, which can run on the guide rail (501) which also guides the clamping devices.

10. 9. The measuring unit according to claim 8, characterized in that the measuring system (520) is an optical measuring system for determining the position of the bar-shaped section in a measuring plane (524) located between the clamping devices, preferably the measuring system has a first laser unit (525-1) and a second laser unit (525-2) which generate laser light curtains extending in the measuring plane, respectively, in measuring directions oriented laterally, in particular perpendicularly to each other, and opposite each laser unit a sensor unit is arranged having a photosensitive sensor for detecting the projection of the part of the bar-shaped section (110-A) through the measuring plane.

11. A method for measuring a residual curvature in a straightened wire-shaped or pipe-shaped workpiece that has passed through a straightening system having two roller straighteners connected in series with each other and having straightening planes oriented in different directions, the method comprising: separating a rod-shaped section (110-A) of a predeterminable length from the straightened workpiece that has passed through the straightening system (400) by a cutting device (370); and measuring the rod-shaped section by a measuring device (500), the measuring device comprising a measuring system (520) for receiving the rod-shaped section (110-A) separated from the straightened workpiece in a measuring position; and a device for determining measurement data representative of the residual curvature of the straightened workpiece. A measuring method characterized by a straightening plane-specific measurement, in which the curvature components determined based on the measurement data are associated with different straightening planes of the roller straightener.

12. 12. The method of claim 11, wherein the straightened material is measured at a rotational position where it passed through the straightening system, since the rotational position of the straightened material about its longitudinal axis does not change between straightening and measurement.

13. In order to measure the bar-shaped section of the straightened workpiece, first the front end section (112) of the straightened workpiece is transferred by controlled feeding to a measuring position in the measuring device (500), after which the straightened workpiece is prevented from self-rotating by a rotation prevention device, in particular by clamping in a horizontal direction, and The bar section (110-A) to be measured is then separated from the remainder of the material to be straightened. The measurement method according to claim 11 .

14. Steps below: forming rotational position markings (115) on said bar section (110-A) suitable for determining the rotational position of said bar section; transferring the bar section having the rotational position markings to the measuring unit (350); and placing the bar section (110-A) having the rotational position markings (115) in a measurement position of the measuring unit at a defined rotational position, the defined rotational position having a known relationship to a rotational position at which the straightened material passed through the straightening system (400); the determined rotational position is adjusted using a rotational position adjustment assistant (550) of the measuring unit, the rotational position adjustment assistant being configured to cooperate with the rotational position markings (115) on the rod section to ensure that the rod section is located at the determined rotational position. The measurement method according to claim 11 .

15. The formation of the rotational position markings (115) is carried out by the following steps: forming a notch or other recessed structure around the periphery of the workpiece; forming a bent section at an end of the material to be straightened; forming a chamfer on an end of the workpiece; Creating a color marking or a laser marking; removing one side of a portion of the insulating layer; Attaching a separately formed, suitably shaped marking member to said rod-shaped section, in particular by fastening, clipping or gluing, preferably by 3D printing; and - gluing preferably self-adhesive stickers to or on the sides of said bar-shaped sections; 15. The method of claim 14, further comprising one of:

16. The measurement of the straightened workpiece includes the following steps: Fixing the straightened material to a first fixing point and a second fixing point spaced apart from the first fixing point as follows, i.e., for each of the fixing points, a vertical and horizontal position of the straightened material is provided, and no forces, apart from gravity, are applied to the straightened material section located between the fixing points; measuring the position of the workpiece in a measurement plane (524) located between the first and second fixing points; and 12. The method of claim 11, further comprising the step of determining the residual curvature using position data for the position of the workpiece at the first fixation location, the second fixation location and within the measurement plane (524).

17. 17. The measuring method according to claim 11, characterized in that an optical measuring system is used for measuring, which preferably uses laser radiation to generate two mutually perpendicular laser light curtains located in the measuring plane and detect them using opposing photosensitive sensors, whereby the position of the straightened material in the measuring plane is determined very accurately in two directions by projection.

18. 1. A method for adjusting a straightening system (400) for straightening a passing wire-shaped or pipe-shaped workpiece (110), particularly for use in a deformation machine for forming straight or bent shaped parts from the workpiece, comprising the steps of: The straightening system (400) comprises two tandemly connected adjustable roller straighteners (400-1, 400-2) with differently oriented straightening planes, a cutting device (370) is used to separate rod-shaped sections (110-A) of a predeterminable length from the straightened material that has passed through the straightening system (400); The bar-shaped sections are measured by a measuring device (500), the measuring device having a measuring system (520) for receiving the bar-shaped sections (110-A) separated from the straightened material in a measuring position, and a device for determining measurement data representative of the residual curvature of the straightened material; the straightening geometry of at least one roller straightener (400-1, 400-2) is changed according to said measurement data in such a way that the residual curvature of the subsequently straightened section of said straightened material is improved with respect to the target residual curvature by the change in said straightening geometry, In things, 11. A method for adjusting an orthodontic system, characterized in that a measuring unit according to any one of claims 1 to 10 is used.

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