Supply system

Abstract

The invention relates to a supply system comprising: a supply device (300) for supplying an elongated-wire-shaped or tubular workpiece (100) to a forming machine; and a measuring unit. The supply device comprises: a receiving device (330) for receiving a workpiece supply in the form of a coil (381); and a straightening system (400) that is connected downstream of the receiving device and has two adjustable roller straighteners (400-1, 400-2) that are connected in series and have differently oriented straightening planes for straightening the workpiece before entry into the forming machine. The measuring unit (350) can be used for measuring residual curvatures on straightened wire-shaped or tubular material which has passed through the straightening system (400) of the supply device (300) and for determining measurement data representing a residual curvature of the straightened material. The supply system also has a cutting device (370) for separating rod-shaped portions (110-A) of predefinable lengths from the straightened material which has passed through the straightening system (400). The measuring unit (350): has a measuring device (520) for receiving, in a measuring position, a rod-shaped portion (110-A) of the straightened material which has passed through the straightening system; and is configured for a measurement that is straightening-plane-specific and makes it possible to assign the curvature components represented by the measurement data to the different straightening planes of the roller straighteners.

Description

FIELD OF APPLICATION AND STATE OF THE ART

[0001] The invention relates to a feeding system according to the preamble of claim 1.

[0002] A feeding system of the type considered here comprises a feeding device designed to feed an elongated wire-shaped or tubular workpiece to a forming machine. The feeding device has a receiving device for receiving a workpiece supply in the form of a coil. Furthermore, the feeding device has a straightening system downstream of the receiving device, comprising two series-connected, adjustable roller straighteners with differently oriented straightening planes for straightening the workpiece before it enters the forming machine. The feeding system also includes a measuring unit for measuring residual curvatures on straightened wire-shaped or tubular workpieces that have passed through the straightening system of the feeding device, and for determining measurement data representing a residual curvature of the straightened workpieces.Based on the measurement data, the roller straighteners of the straightening system can be adjusted so that the material to be straightened has the desired straightening quality.

[0003] Wires, tubes, or other elongated semi-finished materials are often in the form of coils immediately after production and normally need to be straightened before further processing. Straightening is a manufacturing process from the group of forming processes and is used to straighten the elongated material, also referred to here as the straightened material, before further processing, into a form that is as straight as possible, i.e., into a state with little or no residual curvature. In a straightening process, the material is conveyed from a material supply through a straightening system, and the straightening system produces straightened material or straightened straightened material from the material by forming it in a straightening operation.

[0004] Straightening systems of the type considered in this application have at least two roller straighteners. A roller straightener comprises a plurality of passive, i.e., non-rotationally driven, straightening rollers with mutually parallel axes of rotation, which are arranged alternately on opposite sides of a throughput path in a throughput direction and, when operated with peripheral sections in contact with the workpiece, define a straightening geometry. Using a roller straightener, it is possible to change one-dimensional initial curvatures (curvatures before entering the roller straightener) of a workpiece in one plane, so that a defined residual curvature is present in this plane after the straightening process. Typically, the goal is an end product without residual curvature, i.e., a straight end product. Straightening systems with two roller straighteners connected in series are usually used, which eliminate the initial curvatures in two mutually perpendicular planes.

[0005] Straightening systems with roller straighteners do not rotate and therefore differ fundamentally from rotating straightening systems with so-called straightening wings, which apply straightening forces in many different planes.

[0006] In adjustable roller straighteners, at least one of the straightening rollers can be adjusted in a feed direction oriented transversely to the feed direction. This allows the straightening geometry of the roller straightener to be modified to achieve a better straightening result. Depending on the type of roller straightener, a straightening roller can be adjusted manually, semi-automatically, or automatically by means of an associated actuator (e.g., servo motor, pneumatic cylinder, hydraulic cylinder, etc.) in response to control signals from a control unit.

[0007] Inadequate leveling results can occur, for example, when using freshly prepared material after a coil change or after switching to a different process. Material inhomogeneities, changes in material properties, and / or wear on leveling rolls can also lead to deterioration of leveling results during the ongoing process. Raw material is also subject to manufacturing tolerances. Changes can be detected through regular spot checks. If an unacceptable deterioration in leveling quality occurs, the leveling system should be adjusted by changing the leveling geometry.

[0008] In practice, a machine operator requires considerable experience and skill to ensure sufficiently consistent leveling quality on the machine being operated. There are already approaches to achieving production processes with reproducible leveling quality, regardless of the machine operator's skills.

[0009] Patent DE 195 03 850 C1 describes a non-rotating straightening device for bending machines with an integrated measuring device. The straightening device comprises at least one non-rotating straightening unit for wire or strip material, operating in at least one straightening plane. The straightening unit has several consecutive straightening rollers that process the material and are adjustable in the straightening plane and transversely to the material's throughput axis by means of at least one actuator.In the direction of travel of the material behind the straightening device, a material bending measuring device is provided in which at least one measuring section is provided for a material section of predetermined length and along the measuring section at least one mechanical and / or electronic and / or optical scanning device is arranged to determine the extent of the bend and the direction of bending. The scanning device can generate signals representing the measured bending of the material section, and the actuating drive of at least one straightening roller is an actuating drive that responds to the signals with corrective actuating movements. The measuring device is configured for a straightening plane-specific measurement, which allows an at least approximately unambiguous assignment of the measured data or the curvature components represented by the measured data to the different straightening planes of the roller straighteners.

[0010] For the technological background of the measurement of curvatures on aligned workpieces, please refer to documents JP H05337582 A, JP S6182939 A or WO 2017 / 183010 A1. TASK AND SOLUTION

[0011] It is an object of the invention to provide a feeding system of the type mentioned at the outset which enables precise measurements of the residual curvature on straightened material and provides meaningful measurement results which can be used during setup and operation of the straightening system in order to quickly and systematically optimize the straightening geometry of the roller straighteners so that good straightening results can be achieved.

[0012] This object is achieved according to a formulation of the invention by a feeding system having the features of claim 1. The wording of all claims is incorporated into the content of the description by reference.

[0013] An essential component of the feeding system is a feeding device designed to feed an elongated wire-shaped or tubular workpiece to a forming machine. The feeding device comprises a receiving device for receiving a workpiece supply in the form of a coil and a straightening system downstream of the receiving device. The straightening system comprises two adjustable roller straighteners connected in series with differently oriented straightening planes for straightening the workpiece before it enters the forming machine. The straightening planes are preferably oriented perpendicular to one another; in particular, one of the straightening planes is horizontal and the other is vertical. The feeding device thus produces more or less well-straightened continuous material (wire or tube) from the wound material of the coil.

[0014] To ensure sufficient straightening quality, the feeder is equipped with a measuring unit designed to measure residual curvature on the straightened material that has passed through the feeder's straightening system. These measurements are used to determine measurement data that represent the residual curvature of the straightened material, thus enabling a quantitative description of the curvature state. The measuring unit is adapted to the design and functional properties of the feeder to ensure the most interference-free measurement possible.

[0015] The measuring unit is a separate unit from the feeder that can be temporarily or temporarily connected to the feeder for measuring purposes to perform setup work. The feeder can then be moved into its working position on the forming machine to which the straightened material is to be fed. The measuring unit can also be used to set up the straightening systems of other machines equipped with a straightening system.

[0016] The feeding system of the claimed invention has the following special features according to a formulation of the invention.

[0017] The feed system comprises a cutting device for cutting rod-shaped sections of a predefined length from the straightened material that has passed through the straightening system. The measurement is then performed on rod-shaped sections (rods) of a predefined length (rod length) that have been cut from the straightened material that has passed through the straightening system using the cutting device. During each measuring operation, a single rod is measured. To enable such a measurement, the measuring unit comprises a measuring device for receiving a rod-shaped section in a measuring position and for determining measurement data that represent a residual curvature of the straightened material. The measuring unit is configured for a straightening plane-specific measurement, 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 straighteners.

[0018] The invention is based, among other things, on the following considerations. A roller straightener only straightens in a single straightening plane. If the straightening system comprises two roller straighteners running one after the other, each with different, particularly perpendicular, straightening planes, curvatures in the two straightening planes can be assessed independently of each other to a first approximation. It was recognized that for the targeted adjustment or positioning of the straightening rollers during the setup process or within the framework of a closed-loop control system, it is important to be able to clearly assign the measurement results obtained on the straightened workpiece to the individual straightening planes. Measurements that allow this are referred to in this application as "straightening plane-specific or straightening plane-selective measurements."

[0019] It is known to measure the straightness or residual curvature of a section of the straightened workpiece that is still connected to adjacent sections of the workpiece. If necessary, the measurement can be performed while the workpiece is moving, i.e., during phases in which it is in motion. The workpiece can also be temporarily immobilized for the measurement (cf. DE 195 03 850 C1). It is considered a disadvantage that the stresses and forces acting from other sections of the workpiece may influence the shape of the measured section, so that the true curvature is not measured.

[0020] According to the claimed invention, the measurement is performed on rod-shaped sections or rods of a predetermined length, which were separated from the straightened material after passing through the straightening system using a cutting device. Due to the separation from the subsequent remainder, the rod to be measured can relax without external force, so that the shape of the rod represents the true curvature conditions at least approximately unadulterated. According to the inventors' findings, significantly more interpretable measurement results can be achieved if a relatively short rod-shaped section is cut from the straightened material and this rod is then measured or subjected to a straightness test.

[0021] This allows precise quantitative statements about curvature components to be obtained using measurement methods that are relatively easy to carry out and evaluate, and these can be clearly assigned to the different alignment planes during the evaluation.

[0022] Preferred rod lengths are usually significantly less than one meter; depending on the stiffness of the straightened material, they can be, for example, between 300 mm and 700 mm.

[0023] Some advantages of this configuration can also be understood as follows. Many conventional straightness measuring systems are designed to provide a global statement about the curvature of the material being straightened, for example, to distinguish sufficiently well-straightened material with the desired straightening quality from material with insufficient straightening quality. In contrast, the measuring unit or the measuring method of the claimed invention can not only determine global values ​​for the residual curvature, but the information resulting from the measurement about the curvature of the rod-shaped section can be separated into curvature components that can be clearly assigned to the individual straightening planes of the straightening system. With such a straightening plane-specific or straightening plane-selective measurement, it is possible to quantitatively determine which component of a determined residual curvature was caused by which of the at least two straightening devices.

[0024] With this information on the curvature of the material to be straightened, broken down by straightening planes, the roller straighteners can then be adjusted in a targeted manner, for example during the setup of the straightening system, in order to achieve a suitable setting for the straightening rollers with just a few attempts. If, for example, a straightening system has a first roller straightener with a vertically oriented first straightening plane and, downstream of this, a second roller straightener with a horizontal straightening plane, the horizontal and vertical components of the residual curvature can be quantified separately using the measured data. Accordingly, during a setup process, for example if a detected residual curvature occurs predominantly or exclusively in one of the straightening planes, the adjustment of the straightening rollers can be concentrated on the straightener whose straightening plane is affected by the excessive residual curvature.

[0025] The measuring unit can work with cut bars that have been cut using a cutting device belonging to a machine upstream in the process, e.g., a straightening and cutting machine whose end products are straightened bars. A straightening and cutting machine typically comprises a feeder, a length measuring device, and a cutting device controlled by signals from the length measuring device. In these cases, a separate cutting unit is not required on the measuring unit.

[0026] According to a further development, the measuring unit has a cutting device for cutting rod-shaped sections of a predefined length from the straightened material passing through the straightening system. The measuring device is located downstream of the cutting device in the direction of material flow. Due to the integrated cutting device, the measuring unit, as a standalone unit, is capable of cutting rod-shaped sections of suitable lengths from straightened continuous material and performing straightness measurements or residual curvature measurements on these sections.

[0027] The cutting device can be mounted together with the measuring device on or to a common frame of the measuring unit to ensure a fixed positional relationship and form a functional unit that can be used, for example, as a setup station. One embodiment of such a self-contained measuring unit is explained in more detail below.

[0028] To implement a leveling plane-specific or leveling plane-selective measurement, the measuring unit is preferably configured such that the workpiece is measured in the rotational position in which it passed through the leveling system. The term "rotational position" refers to the rotational position or rotational orientation with respect to its own rotation around the longitudinal axis of the workpiece. While leveling plane-specific measurement data could also be determined by measuring any rotation of the workpiece between separation and measurement, and then correcting the measurement data determined with the measuring device with respect to the direction of rotation, it is considered significantly simpler and more accurate to exclude such rotations through process-related and design measures.

[0029] Since a bar of a suitable length is separated from the rest of the material to be straightened for measurement, any rotation of the bar around its longitudinal axis between the act of separation and the act of measurement should be avoided in order to enable clear assignment of the measurement results to the corresponding roller straightener. This can be a problem, especially when processing round material, for example if it is placed in such a way that it rolls along an inclined surface between separation and measurement. When processing material with a profiled cross-section, for example with a rectangular cross-section, simple measures can be sufficient to prevent self-rotation, for example by placing the material to be straightened with one of its flat surfaces on a straight or flat surface.

[0030] According to a further development, the measuring unit is characterized by anti-rotation devices configured such that the rotational position of a severed rod-shaped section intended for measurement remains unchanged about its longitudinal axis between straightening and measuring, such that the material to be straightened can be measured in the rotational position in which it passed through the straightening system. Anti-rotation devices and / or anti-rotation measures thus ensure that the rotational position of the material about its longitudinal axis remains unchanged between straightening and measuring. Preferably, active or actuatable anti-rotation devices are provided, which can be switched between a neutral configuration without intervention on the material to be straightened and an intervention configuration with contact with the material to be straightened in response to control signals from a control unit.

[0031] According to a further development, the measuring unit has a control unit which, in an operating mode, is configured such that the cutting device and the measuring device are controlled or operated in a coordinated manner such that a front end section of the straightened material to be straightened, which has been conveyed to a measuring position in the measuring device by means of a controlled feed, is secured against self-rotation by means of anti-twist devices of the measuring system, e.g., by clamping, and only then is the cutting device controlled in order to separate the rod-shaped section to be measured, which is secured against twisting, from the rest of the material to be straightened. By clamping the material to be straightened or by another anti-twist fixing measure before separation, the separated material to be straightened can be reliably brought to a standstill.

[0032] Coordination between cutting and measurement is particularly easy to achieve in measuring units with integrated cutting devices. However, control coordination is also possible with external cutting devices, i.e., those that are not part of the measuring unit but belong to another unit.

[0033] In some variants, the material to be straightened is first conveyed into the area of ​​the measuring device, where it is secured against twisting, and only then separated from the rest of the material. In one embodiment of the measuring device, the anti-twist protection can be ensured using transversely movable elements of a clamping device.

[0034] It is also possible to provide a rod transport device which is configured to grasp a section of the straightening material to be separated before carrying out the cutting operation, to transport it to the measuring device after separation from the rest of the straightening material and to insert it there with an unchanged rotational position or to deposit it and to release it after the rod-shaped section has been received in the measuring device and secured against rotation.

[0035] This can also be used to perform in-process measurement / control, where straightened bars are fed to the measuring device regularly or irregularly during the production process according to a predefined schedule or on an ad hoc basis, and measured there to assess the straightening quality and, if necessary, make compensating adjustments to the straightening system settings. Bars removed from the material flow for testing purposes can then, if possible, be returned to the subsequent production step, although this is not mandatory. Straightened bars can therefore be removed from the material flow from time to time for measurement purposes and, if necessary, returned to the material flow after the measurement has been completed.

[0036] According to a further development, the straightened workpiece is fixed for the purpose of measurement at a first fixing point and a second fixing point located at a distance from the first fixing point in such a way that a vertical position and a transverse position of the workpiece (e.g. in the horizontal direction transverse to the longitudinal direction of the rod) are specified for each of the fixing points and a section of the workpiece lying between the fixing points is free of forces except for the forces of gravity. The position of the workpiece is then measured in a measuring plane lying between the first and second fixing points. This can, for example, be located centrally between the fixing points. The residual curvature of the wire section lying between the fixing points is then determined using position data for the position of the workpiece at the first fixing point, the second fixing point and the measuring plane.

[0037] The measuring device can be designed with a first and a second clamping device that supports the workpiece at the corresponding fixation points and has clamping elements that can be moved transversely. These elements, when moved toward the workpiece, can thereby fix the transverse position upon contact. This simultaneously provides protection against self-rotation.

[0038] According to a further development, the measuring device has a first clamping device on a side facing or to be faced by the cutting device (inlet side) and a second clamping device spaced longitudinally therefrom. Components of a measuring system are arranged in a region between the clamping devices. The measuring system defines a measuring plane oriented transversely, in particular perpendicular to the longitudinal direction of the measuring device, and is designed to determine the position of the applied rod-shaped section in the measuring plane. The measuring plane is preferably located centrally between the clamping devices, where the greatest deflections of the fixed rod-shaped section are typically expected, which benefits the measuring accuracy.

[0039] According to a further development, each of the clamping devices has a support roller mounted with a horizontal axis of rotation and two transverse positioning elements, e.g., transverse positioning rollers, adjustable by means of a drive, such that an inserted rod-shaped section can be fixed at a fixation point defined in the vertical direction and in the horizontal direction. The upper section of the lateral surface of the support roller can determine the vertical position, while the laterally positioned transverse positioning elements specify the position in the horizontal direction.

[0040] In such embodiments of the measuring device, the anti-twist protection can be ensured by means of the transverse positioning elements, in particular rollers, of the clamping device, which are displaceable in the transverse direction and thus function as anti-twist devices. If a rod-shaped section is gently clamped laterally by means of transverse positioning elements with a vertical axis of rotation, essentially only the degree of freedom of rotation of the rod about its longitudinal axis is eliminated, while the clamping in the horizontal direction between essentially point-like contact points between the support rollers and the outer side of the rod-shaped section does not significantly impede any possible sagging of the rod or deflections in vertical directions. Thus, the true state of curvature can be measured on a rod-shaped section that is supported at two spaced-apart points and is otherwise essentially only subject to gravity.

[0041] As an alternative to roller-shaped transverse positioning elements, other, possibly fixed, transverse positioning elements can also be provided, e.g., blocks with convexly curved contact surfaces. The contact surfaces with the workpiece should preferably be designed so that only a point-like or small-area contact occurs, so that the aligned rod is clamped only horizontally between essentially point-like contact points, thus not significantly impeding any possible deflection in the vertical direction.

[0042] The anti-rotation devices can therefore be elements with a suitable geometry that enable point or linear contact between the clamping device and the rod-shaped section. These include, for example, the rollers mentioned above, but also non-rotatable elements that have a point or radius at least in the contact area, e.g., a cylindrically or spherically curved contact surface.

[0043] According to a further development, a distance of the clamping device measured parallel to the longitudinal direction is continuously adjustable, allowing the measuring device to be easily adapted to rod-shaped sections of different lengths. The rod-shaped sections intended for measurement are in most cases significantly shorter than one meter; depending on the stiffness of the straightened material, their length can be, for example, between 300 mm and 700 mm, or even less (for relatively thin rod materials).

[0044] Although one of the clamping devices can be fixed and only the other can be moved, the clamping devices are preferably mounted on carriages that run on guide rails attached to the top of a horizontally aligned base plate of the measuring system. This allows both clamping devices to be continuously moved along the same axis and then fixed in the desired positions.

[0045] In order to accurately position the measuring plane for different rod lengths, a further development provides for components of the measuring device to be attached to a support mounted on a carriage that can be moved along the guide rails that also guide the clamping devices. This creates an extremely stable arrangement that is easily adaptable to different dimensions of the rod-shaped sections to be measured.

[0046] In principle, any measuring device can be used for the metrological recording of the straightened material after it has passed through the straightening system, i.e. for the measurement, which provides quantitative information about the residual curvature in the straightening planes of the roller straighteners and allows a clear assignment of the measured residual curvatures to the straightening planes.

[0047] The measured value does not have to directly correspond to the residual curvature; it is sufficient if the measured value represents the residual curvature. The measurement can be performed tactile (i.e., by contact) or non-contact, for example, using optical and / or electromagnetic devices. It is important that the measurement technology used to adjust a straightening device allows for statements about the residual curvature or the straightening quality in the straightening plane in which the respective straightening device operates.

[0048] According to a further development, the measuring device comprises an optical measuring system that uses laser radiation to generate two perpendicular laser light curtains located in the measuring plane. These are detected by opposing light-sensitive sensors. This allows the position of the target object in the measuring plane to be determined with high precision in two directions using shadow projection. The non-contact measurement does not affect the shape of the bar being measured.

[0049] The residual curvature present in the curvature plane influenced by the respective roller straightening device (plane perpendicular to the rotation axes of the straightening rollers) can then be easily determined from the distance in the measuring plane between the measured position of the wire section and a reference position located in the measuring plane, which would exist if the straightened material had the desired residual curvature. This reference position preferably does not lie on a straight line connecting the two fixing points, but rather takes into account the deflection of a straightened material resting on the fixing points due to gravity. To determine the position of this reference point, suitable material-specific straightening material parameters can be used, modified if necessary by the fact that the straightened material is deformed several times during the straightening process and thus possibly altered with regard to its elastic properties.

[0050] Within the scope of the claimed invention, different designs of the feeding device are possible.

[0051] According to a further development, the workpiece supply is wound onto an interchangeable reel, and the receiving device is designed such that the reel can be picked up by the receiving device and, when picked up, is mounted so that it can rotate about a horizontal axis of rotation. An advantage of a horizontal orientation of the reel axis is that components that can be positioned high above the hall floor are used to further guide the unwound material, thus requiring only minimal lateral space. In variants, a vertical orientation of the reel axis can also be provided.

[0052] In some designs, a particularly convenient and simple reel change is achieved by the fact that the support device has two axially parallel support rollers with horizontal rotation axes, onto which the reel can be placed in such a way that the circumference of the reel's side elements rests on the two support rollers, and the position of the rotation axis is fixed in space. This eliminates the need to disassemble or rebuild bearing units in the area of ​​the rotation axis when changing the reel.

[0053] Preferably, the reel is actively driven. For example, a drive controlled by a control unit can be provided that engages one of the support rollers and can drive it under the control of the control unit. An active reel drive can contribute to gentle material conveyance with minimal voltage fluctuations.

[0054] According to a further development, the receiving device has a deflection device with an upper deflection roller for receiving the workpiece unwound from the workpiece supply and a device arranged below the upper deflection roller for receiving a workpiece loop before entering the straightening system.

[0055] According to a further development, the device for receiving a workpiece loop arranged below the upper deflection roller comprises a vertically oriented buffer storage in the form of a storage box partially open at the top and, between the upper deflection roller and the buffer storage, an auxiliary feed device which can be driven by means of an auxiliary drive and is configured to convey the workpiece to the downstream buffer storage at a predeterminable conveying speed.

[0056] Preferably, a sensor system is provided for detecting the fill level of the buffer storage and for generating sensor signals representing the fill level, wherein a control device is configured such that the conveying speed of the auxiliary feed device can be controlled depending on sensor signals from the sensor system. Thus, overfilling or underfilling of the buffer storage can be avoided.

[0057] It is also possible for the device for receiving a workpiece loop, located below the upper deflection roller, to have a lower deflection roller. This can be arranged and dimensioned so that the material can then flow directly into the straightening system in a horizontal direction.

[0058] The measuring unit and the feeding device are system components of the feeding system. They can also represent a protectable invention on their own, i.e., independently of the other system component. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Further advantages and aspects of the invention emerge from the claims and from the description of embodiments of the invention, which are explained below with reference to the figures. Fig. 1 shows components of a feeding device for feeding wire material from a wire coil to a forming machine (not shown), wherein the feeding device is arranged at a setup station with an integrated straightness measuring system; Fig. 2 shows the straightening system of the feeding device Fig. 1 in magnification; Fig. 3, 3A shows in Fig. 3 the measuring device of the setup station Fig. 1 in magnification and in Fig. 3A a detailed view of the measuring plane; Fig. 4A bis 4C show a variant of the method in which anti-rotation devices are used to prevent the self-rotation of a separated straightened round rod between separation from the rest of the wire and the measurement; Fig. 5A bis 5D show an alternative process variant in which a straightened rod is cut from flat material and measured. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0060] The following describes exemplary embodiments of feeding systems as well as methods and systems for setting up a straightening system designed for straightening continuous wire-shaped straightening material. The straightening material, in this example a wire, can be further processed in a forming machine to produce straight or bent formed parts from the straightened material. The straightening system is integrated into a feed device designed to supply a forming machine (not shown in detail) with straightened wire as input material during ongoing production. To set up the feed device, a measuring unit belonging to the feed system is used. This measuring unit is structurally and functionally adapted to the feed device and serves as a temporarily used auxiliary device during setup.

[0061] The Fig. 1 shows components of a wire processing system designed and configured to process elongated workpieces 110 in the form of metallic wires, which are available as a workpiece supply in the form of a so-called coil, i.e. a wire bundle wound like a spool. From the workpiece material, which is originally available in great lengths on the workpiece supply, more or less large quantities of similar or dissimilar shaped parts are produced by forming in a computer-numerically controlled production process. The shaped parts can be, for example, coil springs, in particular compression springs or tension springs, or bent parts of a different geometry. Shaped parts can generally be bent two-dimensionally or three-dimensionally, and may also be in the form of straight bars (e.g., in straightening machines or bar processing machines).The Cartesian xyz machine coordinate system is used to better describe directions and positional relationships.

[0062] When configured ready for operation, the wire processing system comprises a forming machine (not shown) which can be designed as a spring coiling machine, for example, in the production of coil springs.

[0063] Furthermore, a device 300 is provided for feeding the elongated wire-shaped workpiece material to the forming machine. The device 300 is also referred to in this application as the feeding device 300. The feeding device of the exemplary embodiment is a forming machine that produces a straightened wire from more or less strongly curved wire from the wound wire stock by forming it. Fig. 1 shows some components of the feeding device 300 together with an associated measuring unit 350 of a feeding system.

[0064] One task of the feed device 300 is to feed the wire to a downstream forming machine or its feed device in a straightened form (residual curvature close to zero within the tolerance range) at any time and as precisely as possible at the speed required at that time. The feed device 300 has its own control unit 390, which communicates with the control unit of the forming machine. The functionalities of both control units can be integrated into a single control unit.

[0065] After setup at the setup station is complete, the feeding device is moved into its working position on the forming machine to be supplied. For this purpose, the components shown are mounted on a movable platform, which can be linearly displaced on guide rails, mounted for rotation about a vertical axis, or moved unguided (e.g., on rollers or wheels).

[0066] The feeding device comprises a feeding unit 310, which has a receiving device 330 for receiving a workpiece supply 381 in the form of a coil and a downstream straightening system 400 for straightening the workpiece before it enters the forming machine. The straightening system 400 is in Fig. 2 shown in detail.

[0067] Fig. 1 shows the feed unit 310 at a measuring unit 350 or a setup station 350, which enables a machine operator to carry out all the work required to adjust the straightening system to the workpiece material used on a straightening system 400, which is located at the measuring unit or the setup station 350, in such a way that the feed unit, in productive operation, i.e. when the feed unit is in its working position on a forming machine, can deliver straightened workpiece material with a high level of straightening quality, in particular material with no residual curvature or with residual curvature only within the tolerance range.

[0068] The workpiece supply (coil) is held on an interchangeable reel 335, which is picked up by a holding device 330 and, when picked up, is mounted so as to rotate about a horizontal axis of rotation. The mounting does not take place in the area of ​​the reel's axis of rotation; instead, two axially parallel support rollers 332, 333 with horizontal axes of rotation are attached to the base area. These support rollers are components of the holding device 330. The reel is placed on the two support rollers so that the circumference of the disc-shaped side elements of the reel rests on the two support rollers and the position of the axis of rotation is fixed in space. In the example, this is an active reel with its own drive. The drive 334 engages the front support roller 333 and can drive it under the control of the control unit 390.

[0069] The unwound wire is guided over a deflection device 340, which has an upper deflection roller 340-1 and a lower deflection roller 340-2, which are mounted on a vertical support 341 so as to be rotatable and parallel to their axes. The upper deflection roller is designed as a vertically movable dancer roller with spring return. The drive motor for the support / drive roller is controlled by a position sensor of this roller. The lower deflection roller is wrapped around approximately three-quarters of its circumference in such a way that the outlet, i.e., the upper side of the lower deflection roller 340, is level with the inlet-side passage opening of the straightening system 400.

[0070] The wire is thus guided essentially horizontally from the lower deflection roller to the straightening system 400. Between the deflection device and the straightening system is a wire guide device 375, the output of which is aligned with the input of the downstream straightening system 400. A wire end detection device can be integrated into the wire guide device.

[0071] An alternative construction belonging to the claimed invention is shown in Fig. 1 shown or indicated by dashed lines. In this case, the lower deflection roller is omitted. The construction comprises a buffer storage 600 in the form of a relatively flat storage box that is open on one side (here partially at the top) and an upstream auxiliary feed device 610, which can be arranged, for example, behind the upper deflection roller 340-1. The auxiliary feed device can be driven by means of an auxiliary drive and is configured to convey the workpiece, in the example the wire, at a predeterminable conveying speed to the downstream buffer storage 600. The buffer storage has an inlet and an outlet for the workpiece. The buffer storage is designed such that the workpiece can form a workpiece loop 111 of variable length in the buffer storage between the inlet and the outlet.This allows speed differences between the areas in front of and behind the buffer storage to be compensated. Preferably, a sensor system is provided for detecting the fill level of the buffer storage and for generating sensor signals representing the fill level. The control device can then be configured such that the conveying speed of the auxiliary feed device can be controlled or is controlled as a function of sensor signals from the sensor system. If necessary, a buffer storage device can also be installed horizontally, so that the workpiece loop forms in a plane that is essentially horizontally aligned. For further details and variants, reference is made to WO 2020 / 224977 A1, the disclosure of which regarding the design of the feed device is incorporated into this description by reference.

[0072] The straightening system 400 comprises two independently adjustable roller straighteners 400-1, 400-2, arranged directly one behind the other, each with a number of axially parallel straightening rollers. Seven straightening rollers are provided in each case, but other numbers, such as five to nine, are also possible. The rotational axes of the straightening rollers of the straightening devices arranged one behind the other are aligned orthogonally to each other.

[0073] In a roller straightener, the straightening rollers, due to their off-center alignment with respect to a neutral axis of the material to be straightened, generate alternating bends that deform the material to be straightened into the plastic range and thus straighten it. In contrast to a roller straightener, the straightening rollers here are passive, or not rotationally driven; thus, there are no drives for rotating the straightening rollers. The wire is pulled through the roller straighteners. For this purpose, a feed device 385 is provided, which is arranged downstream of the straightening system 400 in the direction of material flow and serves, among other things, to pull the wire material through the two roller straighteners 400-1, 400-2 of the straightening system 300 toward downstream components.

[0074] The components of the straightening system 400 are supported by a frame part, which can also house the control unit 390 of the feed unit 310. The frame part also supports the feed device 385. In the example, the feed device 385 is designed as a roller feed device and, in other embodiments, can also be designed as a belt feed device or a gripper feed device. An optional, possibly manually operable clamping device can be provided downstream of the feed device 385 in the material flow direction, with which the axial position of the passed wire can be fixed if necessary.

[0075] Further details are explained using the example of the first roller straightening device 400-1 operating in the vertical plane (xz plane).

[0076] The first roller straightener 400-1 has seven passive straightening rollers R1, ... R7 with mutually parallel, horizontal axes of rotation, which are arranged alternately on opposite sides of a throughput path (parallel to the x-axis) in a throughput direction 115. During operation of the straightening system, the straightening rollers, with their circumferential sections touching the material 110 to be straightened, define the effective straightening geometry of the roller straightener. The first roller straightener 400-1 essentially changes the curvature only in a vertical plane (xz-plane), the straightening plane. The second roller straightener 400-2, responsible for straightening in a horizontal plane, has a similar structure; here, the straightening roller axes of rotation run vertically.

[0077] In the example case, all seven straightening rollers are designed as automatically adjustable straightening rollers and can be automatically adjusted bidirectionally in response to control signals from the control unit 390 by means of servomotor drives 405-1, .., 405-7 independently of one another in a feed direction oriented perpendicular to the feed direction (parallel to the z-axis).

[0078] There are also variants in which all straightening rollers are manually adjustable. Adjustment screws and position indicators can be provided for this purpose. There are also examples in which some of the straightening rollers (e.g., two, three, or four) are automatically adjustable, while others (e.g., three, four, or five) are manually adjustable.

[0079] Due to the multitude of adjustment options, a highly experienced machine operator is required to correctly adjust a roller straightener. In any case, the adjustment process, or setup, requires a considerable amount of time.

[0080] Setup is facilitated by the fact that the feed system includes a measuring unit 350, which is adapted to the structural and functional conditions of the feed device 300 and enables a targeted setup procedure in a short time. The measuring unit 350 serves as a setup station.

[0081] The measuring unit or setup station 350 comprises a cutting device 370, with which, during the adjustment work on the straightening system, test-straightened rod-shaped wire sections 110-A are cut from the supplied wire and thus prepared for a straightness test. In the example, an automated cutting device 370 is provided; alternatively, a manually operable cutting device can be provided. Furthermore, the setup station 350 has a measuring device 500.

[0082] The wire sections or wire rods 110-A cut by the cutting device are checked for straightness and residual curvature using the downstream measuring device 500. Anti-rotation devices ensure that the rotational position of the material rod intended for measurement remains unchanged around its longitudinal axis, so that the wire is measured in the rotational position in which it passed through the straightening system.

[0083] The measuring device 500 and the associated cutting device 370 are components of the measuring unit 350, which, optionally together with other components, forms a self-contained unit that can serve as a setup station 350. Therefore, the same reference numeral 350 is used for the setup station and the measuring unit.

[0084] Fig. 3 shows an enlarged detailed view of components of the measuring device 500. The measuring device 500 comprises a first clamping device 510-1 on the side facing the cutting device 370 and, at a distance behind it, a second clamping device 510-2. The clamping devices are mounted on carriages that run on two guide rails 501 that are fastened to the upper side of a horizontally oriented base plate 502. The axial distance between the clamping devices, measured parallel to the direction of travel, can thus be continuously adjusted. Each of the clamping devices has a support roller 512-1, 512-2 mounted with a horizontal axis of rotation and two pneumatically adjustable transverse positioning rollers 514-1, 514-2. This allows an inserted wire rod to be fixed at a precisely defined fixing point in both the vertical and horizontal directions.The rollers contact the wire without introducing additional forces or torques, so that the wire rod rests at defined fixation positions at the front and rear, and in the area between them is subject only to gravity. The rod cannot rotate around its axis when gently clamped between the horizontally movable rollers 514-1, 514-2.

[0085] Components of a measuring system 520 are mounted in the area between the clamping devices 510-1, 510-2. These are carried by a cross-shaped carrier 522 mounted on a carriage that can move along the guide rails 501, which also guide the clamping devices. The measuring system 520 is an optical measuring system that can determine the position of the applied wire with high precision in a measuring plane 524 oriented perpendicular to the x-direction. A second laser unit 525-2 is mounted above the straight connecting line between the fixation points. This laser unit generates a laser light curtain located in the measuring plane 524, which falls into the detection range of a photosensitive sensor 527-2 on the opposite side, so that the position of the wire in the transverse (horizontal) direction can be precisely detected in the shadow cast. The position in the vertical direction is detected using a first laser unit 525-1 and the opposite sensor 527-1.The measurement is preferably carried out in the middle between the two fixation elements using the two lasers in the horizontal and vertical directions.

[0086] The enlarged detail in Fig. 3A illustrates a typical measurement situation. The plus symbol represents the intersection of the connecting lines between the fixation points 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 distance values ​​ΔH in the horizontal direction and ΔV in the vertical direction, a residual curvature of the wire rod in the respective straightening planes can be calculated. The results are therefore specific to the straightening plane and are evaluated accordingly to provide, if necessary, separately determined instructions for improving the straightening geometry for each of the two roller straighteners.

[0087] The evaluation takes into account that the wire rod experiences a certain amount of deflection due to gravity alone, the extent of which depends on the material properties and the distance between the fixation points. This contribution is factored out during the evaluation. The measurement results in a quantitative value for the residual curvature, which can have contributions in both the horizontal and vertical directions. Based on these measured values, the straightening geometry of the roller straighteners is then adjusted so that the residual curvature disappears for the next piece of wire.

[0088] The inventors identify a potential problem in the processing of round material. A round bar that still has a significant bulge in the horizontal plane after straightening may, upon insertion into the measuring device, automatically roll into a stable rotational position in which the bulge sags downwards. This would simulate a bulge in the vertical direction that is not actually present, leading to erroneous measurement results and, consequently, incorrect feeds and / or incorrect feeds at the wrong point on the straightening device.

[0089] To ensure that the measurement results can be precisely assigned to the different straightening planes or roller straighteners (horizontal and vertical), special measures are taken, if necessary, to ensure that the wire rod intended for the measurement cannot rotate around its longitudinal axis between the separation of the remaining material to be straightened and the measurement. The measuring unit 350 is configured for a straightening plane-specific or selective measurement. This will be explained in more detail below using examples.

[0090] One in Fig. 4A bis 4C The schematically illustrated process variant is suitable for many materials with different cross-sectional shapes, especially for round material. The procedure is such that the front end section 112 of the straightened wire, which adjoins the front end face 113, is first conveyed to a measuring position in the measuring device 500 by means of a controlled feed (by the upstream feed device 385) ( Fig. 4A ), then by means of the transversely movable rollers 514-1 and 514-2, the clamping devices 510-1, 510-2 are contacted on diametrically opposite sides and are thereby clamped horizontally and thus prevented from rotating ( Fig. 4B ) and that only then is the bar to be measured separated from the rest of the target material ( Fig. 4C ). The measurement then begins using the optical measuring system 520.

[0091] The horizontally movable rollers 514-1 and 514-2 of the clamping devices act as an anti-twist device, contacting the wire material at two contact points diametrically opposite in the horizontal direction with a relatively low pressure, which is dimensioned such that the static friction is sufficient to prevent the rod from rotating around its longitudinal axis, but at the same time the wire rod can relax so that it is otherwise free of forces except for gravity and thus shows those residual curvatures that are to be measured.

[0092] Based on the Figuren 5A bis 5D Another method variant for testing the straightness of bars using the measuring device is explained. First, the wire with a flat rectangular cross-section (see detail) is advanced through the wire feed by means of the feed device 385 to a cutting position. This is characterized, among other things, by the front end 113 of the bar having already reached the support roller of the rear or second clamping device 510-2 and resting there. During this threading operation, the transverse positioning rollers are in their retracted position. The cut is then performed by means of the cutting device 370 ( Fig. 5B ). In the next step ( Fig. 5C ), the cut piece of wire is pushed further forward into its measuring position, in which the wire rod is centered with respect to the central measuring plane and extends beyond the support roller by equal lengths on both sides. No separate device is required for this short wire feed. Rather, the following piece of wire is moved to the rear end of the wire rod to be measured by means of the feed device 385, so that it can effect the horizontal feed like a ram. In the next phase ( Fig.5D), the cross-positioning rollers are moved toward the designated clamping positions using their pneumatic cylinders. The wire piece is also pressed against the rear stop to ensure a defined plane. This secures the wire rod for measurement. It is clearly visible that the connecting line between the front and rear clamping positions does not have to be coaxial with the feed axis of the subsequent wire.

[0093] Advantageous measuring units and procedures were explained using the example of setting up a forming machine in the form of a feeding device which, when used as intended, forms straightened wire material from wire material fed from a coil with varying input curvature using the integrated straightening system, which is fed to a downstream forming machine as "endless material".

[0094] A measuring unit of the type described here can also be used in other ways.

[0095] The straightening system can have exactly two roller straighteners, which preferably produce mutually perpendicular straightening planes. A straightening system can also have three, four, or more roller straighteners. For example, a straightening system can have four straighteners offset by 45°, which can be a favorable option for straightening round wire, for example.

[0096] The forming machine into which the straightening system is integrated can also be a straightening and cutting machine designed to straighten wires or other semi-finished materials with different cross-sectional sizes and shapes that can be processed by straightening, and then cut the straightened material to a desired length. The machine then additionally has a length measuring device and a cutting device, which can preferably be operated automatically based on signals from the length measuring device. The measuring unit can then measure the separated straightened bars. The measuring unit does not require its own cutting device for this purpose. It can also be a bar processing machine that, in addition to the straightening system, a cutting device, and a length measuring device, also has a stripping device for removing sections of the insulation from a metallic starting material coated with an insulating layer.

[0097] A straightening system can also be integrated into a forming machine, which, with the aid of suitable forming tools, can produce small or large series of shaped parts, sometimes with complex geometries, from the straightened material in an automated production process. The forming tools required for forming are then connected downstream of the straightening system. The forming machine can, for example, be a bending machine for producing bent parts from wire, strip, or tube material, or a spring manufacturing machine or a wire nail machine for the mass production of screws, nails, rivets, or the like. The measuring unit can, for example, be used to measure the wire exiting a wire guide of the respective machine.

[0098] The invention can be used for different types of straightening material, in particular for straightening metallic wire or tubular material. The cross-sectional shape of the material can vary, e.g., a circular cross-section for round material, a profiled and / or polygonal cross-section for profile material, or, in particular, a rectangular cross-section for square material. Flat material, such as metallic flat strips with a high aspect ratio between width and height, can also be straightened. The cross-sectional size can also vary. The metallic material can be uncoated or have a coating, e.g., an electrically non-conductive insulating layer made of plastic.

[0099] The straightness inspection or measurement does not have to be performed as described in the example. The straightness inspection can also be performed automatically using at least one camera. For example, with flat material, straightness can be checked in a continuous process using two cameras offset by 90°. Especially with round wires, a camera rotating around the wire or a laser scanner can be used.

Claims

1. Supply system comprising: a supply apparatus (300) for supplying an elongate, wire-shaped or tubular workpiece (110) to a forming machine, wherein the supply apparatus has a receiving device (330) for receiving a workpiece store in the form of a coil (381) and a straightening system (400) which is downstream of the receiving device and which has two adjustable rolling / straightening apparatuses (400-1, 400-2) which are connected one behind the other and which have differently orientated straightening planes for straightening the workpiece before introduction into the forming machine; a measurement unit (350) for measuring residual curvatures on straightened wire-shaped or tubular straightening material which has passed through the straightening system (400) of the supply apparatus (300), and for establishing measurement data which represent a residual curvature of the straightened straightening material; wherein the measurement unit is configured for a measurement which is specific to the straightening plane and which allows association of the curvature portions represented by the measurement data with the different straightening planes of the rolling / straightening apparatuses, characterized in that a cutting device (370) for separating rod-shaped portions (110-A) of a predeterminable length from the straightening material which has passed through the straightening system (400) is provided; the measurement unit (350) has a measurement apparatus (520) for receiving in each case one rod-shaped portion (110-A), which is separated from the straightening material, of the straightening material which has passed through the straightening system in a measurement position.

2. Supply system according to Claim 1, characterized in that the measurement unit (350) has the cutting device (370) for separating rod-shaped portions (110-A) of predeterminable length from the straightening material which has passed through the straightening system, wherein preferably together with the measurement apparatus (500) the cutting device (370) is mounted on or at a common frame.

3. Supply system according to Claim 1 or 2, characterized in that the measurement unit (350) is configured in such a manner that the straightening material can be measured in the rotational position in which it passed through the straightening system (400).

4. Supply system according to one of the preceding claims, characterized by rotation prevention devices (514-1, 514-2) which are configured in such a manner that a rotational position about the longitudinal axis of a separated rod-shaped portion (110-A) which is provided for measurement remains unchanged between the straightening and the measurement so that the straightening material can be measured in the rotational position in which it passed through the straightening system, wherein there are preferably provided actuatable rotation prevention devices which can be switched in response to control signals of a control unit between a neutral configuration without any engagement with the straightening material and an engagement configuration with contact with the straightening material.

5. Supply system according to one of the preceding claims, characterized by a control unit (390) which is configured in an operating mode so that the cutting device (370) and the measurement apparatus (500) are controlled in such a coordinated manner that a front end portion (112) of the straightened straightening material is conveyed by means of a controlled advance to a measurement position in the measurement apparatus (500), afterwards the straightening material is secured to prevent rotation, in particular clamped in a horizontal direction, by means of rotation prevention devices (514-1, 514-2) of the measurement unit (350), and afterwards the cutting device (390) is controlled in order to separate the rod-shaped portion which is intended to be measured from the remainder of the straightening material.

6. Supply system according to one of the preceding claims, characterized in that the measurement apparatus (500) has, at an inlet side, a first clamping apparatus (510-1) and, with spacing therefrom in a longitudinal direction, a second clamping apparatus (510-2), wherein in a region between the clamping apparatuses (510-1, 510-2) components of a measurement system (520) are arranged, in that a measurement plane (524) which is orientated transversely, particularly perpendicularly to the longitudinal direction, is defined and configured to determine the position of the deposited rod-shaped portion (110-A) in the measurement plane (524), wherein each of the clamping apparatuses preferably has a support roller (512-1, 512-2) which is mounted with a horizontal rotation axis and two transverse positioning rollers (514-1, 514-2) which are adjustable by means of a drive in such a manner that an introduced rod-shaped portion can be fixed at a fixing location which is defined in a vertical direction and in a horizontal direction.

7. Supply system according to Claim 6, characterized in that a spacing, measured parallel with the longitudinal direction, of the clamping apparatuses (510-1, 510-2) is adjustable steplessly, wherein preferably the clamping apparatuses are mounted on carriages which run on guide rails (501) which are fixed at the upper side of a horizontally orientated base plate (502) of the measurement system and / or components of the measurement apparatus are fixed to a carrier (522) which is mounted on a carriage which can be displaced on the guide rails (501) which also guide the clamping apparatuses.

8. Supply system according to one of the preceding claims, characterized in that a measurement system (520) of the measurement apparatus is an optical measurement system for determining the position of the rod-shaped portion in a measurement plane (524) which is located between the clamping apparatuses, wherein preferably the measurement system has a first laser unit (525-1) and a second laser unit (525-2) which generate a laser light curtain which extends in the measurement plane in measurement directions which are orientated transversely, in particular perpendicularly to one another, wherein a sensor unit with photo-sensitive sensors for detecting a shadow projection of the part, which extends through the measurement plane, of the rod-shaped portion (110-A) is arranged opposite a laser unit.

9. Supply system according to one of the preceding claims, characterized in that the workpiece store is wound on a replaceable reel (335) and the receiving device (330) is configured so that the reel can be received by the receiving apparatus (330) and is supported rotatably about a horizontal rotation axis in the received state.

10. Supply system according to one of the preceding claims, characterized in that the receiving apparatus (330) has two axially parallel carrier rollers (332, 333) with horizontal rotation axes, on which the reel (335) can be positioned in such a manner that the circumference of lateral elements of the reel is positioned on the two carrier rollers and the position of the rotation axis is fixed in space, wherein preferably a drive (334) which can be controlled via a control unit and which is in engagement with one of the carrier rollers (333) and can drive them under the control of the control unit (390) is provided.

11. Supply system according to one of the preceding claims, characterized in that the receiving apparatus (330) has a redirecting device (340) having an upper redirecting roller (340-1) for receiving the workpiece which is unwound from the workpiece store and a device which is arranged under the upper redirecting roller (340-1) for receiving a workpiece loop before introduction into the straightening system (400).

12. Supply system according to Claim 11, characterized in that the device arranged under the upper redirecting roller (340-1) for receiving a workpiece loop (111) comprises a vertically orientated buffer store (600) in the form of an upwardly, partially open storage box and an auxiliary intake device (610) which is preferably arranged between the upper redirecting roller (340-1) and the buffer store (600) and which can be driven by means of an auxiliary drive and is configured to convey the workpiece at a predeterminable conveying speed to the downstream buffer store (600), wherein preferably a sensor system is provided for detecting the filling level of the buffer store and for generating sensor signals which represent the filling level, wherein a control device is configured so that the conveying speed of the auxiliary intake device can be controlled in accordance with sensor signals of the sensor system.

13. Supply system according to Claim 11, characterized in that the device which is arranged under the upper redirecting roller (340-1) for receiving a workpiece loop has a lower redirecting roller (340-2), the upper redirecting roller (340-1) and the lower redirecting roller (340-2) are rotatably supported in an axially parallel manner on a vertical carrier (341), wherein preferably the upper redirecting roller is in the form of a vertically displaceable dancer roller with resilient restoring and interrogation of the position of this redirecting roller is used to control a drive motor (334) for reel rotation and / or wherein the lower redirecting roller is wrapped around over approximately three-quarters of the circumference thereof and has at the upper side thereof an outlet which is at the height of an inlet-side through-opening of the straightening system (400) so that the workpiece material can run from the lower redirecting roller directly in a horizontal direction into the straightening system (400).

14. Supply system according to one of the preceding claims, characterized in that the straightening system (400) has two rolling / straightening apparatuses (400-1, 400-2) which are connected one behind the other and which are adjustable independently of one another, wherein rotation axes of straightening rollers of the straightening apparatuses are orientated orthogonally relative to one another, preferably in such a manner that a first straightening apparatus defines a vertical straightening plane and a subsequent second straightening apparatus defines a horizontal straightening plane.

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