DE102022210133B3 - Device for feeding an elongated workpiece to a forming machine, retrofit kit and forming system - Google Patents

Abstract

The invention relates to a device (300) for feeding an elongated workpiece (110) to a forming machine, which has a feed device for pulling in the fed workpiece and for conveying the workpiece to a tool area of the forming machine, comprising: a reel unit (380) for receiving a Workpiece supply in the form of a coil made of workpiece material, the reel unit (380) having a frame (320) and a reel (310) carried by the frame, which is rotatably mounted about a reel axis (312), the reel unit having a guide rod arrangement (410) with three or more guide rods (420) arranged distributed around the reel, each of the guide rods (420) extending substantially parallel or at an acute angle to the reel axis from a first end portion to a second end portion, the first end portion (422) is connected to a connection point (424) fixed to the frame and the second end section (425) has a workpiece guide (430) for guiding and / or deflecting the workpiece (110), the second end section (425) having some or all of the guide rods (420 ) can be deflected elastically at least radially to the reel axis (312).

Description

FIELD OF APPLICATION AND STATE OF TECHNOLOGY

The invention relates to a device according to the preamble of claim 1 for feeding an elongated workpiece to a forming machine, a retrofit kit and a forming system.

Forming machines are machine tools that, with the help of suitable tools, can produce smaller or larger series of molded parts with sometimes complex geometry from elongated workpieces such as wire, pipe, strip or the like in an automatic manufacturing process, primarily through forming. The forming machine can be, for example, a bending machine for producing two-dimensionally or three-dimensionally bent parts made of wire material, strip material or pipe material by bending, a straightening machine for straightening workpieces, a nailing machine or a spring manufacturing machine for producing compression springs, tension springs, leg springs or other spring-like molded parts act through spring coils or spring coils. For the efficient production of large quantities of molded parts, highly productive computer-numerically controlled forming machines with numerous machine axes are used today, which are controlled in a coordinated manner via a control device.

When producing molded parts, the workpiece material is drawn in or conveyed from a workpiece supply to the tool area of the forming machine under the control of an NC control program using a feed device of the forming machine. The feeding wire is formed into the desired molded part by the forming tools downstream in the material conveying direction. Before or after the shaping, the workpiece section intended to produce the molded part is separated from the supplied workpiece material by means of a cutting device under the control of the NC control program. This process is repeated cyclically for each molded part.

In devices of the type considered here, the workpiece supply is provided in the form of a coil. The term “coil” here refers to a container of workpiece material wound up like a coil. A wound stock of workpieces intended for processing is picked up in a reel unit before productive operation begins. A reel unit of the type considered here has a reel which is rotatably mounted about a reel axis and can carry the workpiece material in a wound form. The coiler unit is part of a device assigned to the forming machine for feeding the elongated workpiece to the forming machine.

An essential task of such a device is to supply the workpiece material to the forming machine or its feed device without any problems. This can represent a technical challenge, especially in highly dynamic forming machines that work with intermittent feed and/or with strongly fluctuating feed speeds and strong accelerations. Strong accelerations can occur, among other things, when the workpiece material supplied for the cutting operation has to be braked sharply after a forming operation has been completed, sometimes even to a standstill. This creates high dynamic requirements for unwinding the workpiece material from the coil. There are conflicting requirements here, namely, on the one hand, the high accelerations (positive and negative accelerations) required at the feed device of the forming machine and, on the other hand, retaining forces on the coil side.

Despite the large accelerations sometimes required at the feed of the forming machine, the reel should run as smoothly as possible in order to be able to deliver the workpiece material continuously (i.e. in particular without stopping).

In some devices, the reel is passively driven at a more or less constant speed by pulling in the elongated workpiece using the feed device. The speed of the reel depends on how much workpiece material is unwound from the coil and fed to the downstream forming machine. The reel of such devices is also referred to as a “passive reel”.

Other devices have a reel drive, by means of which the reel is usually actively driven at a more or less constant speed, the speed of the reel determining how much workpiece material is unwound from the coil and fed to the downstream forming machine. The reel of such devices is also referred to as an “active reel”.

Both in devices with a passive and with an active reel, the reel speed can be adjusted to the decreasing diameter of the coil to be processed or even when it occurs via a tensioning device attached to the reel that is resiliently biased in a deflection direction and effective up to a maximum deflection a larger or smaller one than the desired workpiece clamping, for example by increasing the reel speed when the deflection arm moves radially outwards or by adjusting it to rotate freely while the position of the deflection arm remains unchanged or by pivoting the deflection arm radially inwards to accelerate the reel speed (cf. DE 30 10 508 C2 ).

Such devices with a clamping device react automatically to changes in the workpiece states of the workpiece drawn in by the feeder device, e.g. to variations in the workpiece tension and/or changing feeder speeds, and try to ensure that the workpiece is removed from the reel as smoothly as possible.

TASK AND SOLUTION

Against this background, the invention is based on the object of providing a device for feeding an elongated workpiece to a forming machine, a conversion kit for retrofitting such a device and a forming machine with such a device, which has a relatively simple and robust structure and requires little space for the coiler unit enables trouble-free workpiece feeding under changing operating conditions.

This object is achieved by a device with the features of claim 1, a retrofit kit with the features of claim 19 and a forming machine with the features of claim 22. Advantageous developments are specified in the dependent claims. The wording of all claims is incorporated by reference into the content of the description.

According to a first aspect of the invention, a device for feeding an elongated workpiece to a forming machine is provided. The forming machine has a feed device for pulling in the supplied workpiece and for conveying the workpiece to a tool area of the forming machine. The feeding device is also referred to as the “feeding device” for short in the context of this application.

The device comprises a reel unit for receiving a workpiece supply in the form of a coil made of workpiece material. The reel unit has a frame and a reel carried by the frame, which is rotatably mounted about a reel axis.

The reel unit has a guide rod arrangement with three or more guide rods which are arranged distributed around the reel or around the reel axis. The guide rods can, for example, be distributed around the reel axis in the manner of a ring. The connection points can, for example, lie on a common circle, but deviations from a circle in the radial direction are possible.

Each of the guide rods extends substantially parallel or at an acute angle to the reel axis from a first end portion to a second end portion at the opposite end.

A “guide rod” is an elongated element whose length (rod length) is usually several orders of magnitude larger than its cross-sectional dimensions. The bar length is measured between the opposite bar ends. An “end section” is a section of the guide rod immediately adjacent to a rod end, the length of which is significantly less than half of the rod length, e.g. less than 40% or less than 30% or less than 20% of the rod length. A guide rod can be made solidly from a suitable rod material. A guide rod can also be tubular, i.e. with a continuous inner cavity. In this way, a guide rod can possibly be created which has a particularly favorable ratio between (compared to a solid rod of the same external dimensions) a relatively low overall weight and rigidity. A guide rod can be essentially cylindrical in shape (round rod), but guide rods with a cross-sectional shape that deviate from the circular shape are also possible, e.g. profile rods with a polygonal cross-section, e.g. with a square cross-section or a generally rectangular cross-section with possibly different edge lengths, or hexagonal cross-section.

Guide rods are preferably made of a relatively solid, in particular metallic, material. Some of the guide rods or all of the guide rods are elastically bendable transversely to their longitudinal direction, but have sufficient rigidity to automatically assume their nominal basic shape, which can be straight, for example, in the absence of larger external forces. For example, a guide rod can be made of spring steel, i.e. a steel material whose yield strength ratio (quotient of yield strength and tensile strength) is in the range of 85% or more. It is also possible for one or more guide rods to be designed to be so rigid or rigid transversely to their longitudinal direction that they can hardly or essentially not be bent elastically.

The first end section of a guide rod is attached to a connection point fixed to the frame den, which means that the area of connection of the guide rod is stationary in relation to the frame of the reel unit. While the first end section is connected to the frame side, the second end section is a free end section. This free end section can be deflected in an elastically resilient manner in some or all of the guide rods with respect to the frame, for example transversely to the longitudinal direction of the guide rod. In particular, the free second end section of three or more guide rods can be deflected in an elastically resilient manner. Transverse forces acting on the second end section can lead to an elastic deformation of a guide rod connected on one side and thus to a deflection of the second end section in the transverse direction. The deflection can have a dominant radial component, i.e. a component that is directed radially with respect to the reel axis. In addition, at least one of the guide rods can be elastically deflectable laterally, in particular in the direction of an adjacent guide rod.

At least one workpiece guide is formed or arranged on or in the second end section. A workpiece guide is the component on a guide rod that comes into contact with the workpiece and specifies at which point or in which area a guided workpiece is guided on the guide rod. A workpiece guide can be used to guide and/or deflect the workpiece. The mechanical interaction between the workpiece guide and the workpiece, which is still under tension and/or in a curved shape after being removed from the coil, determines the extent and direction of any deflection of the second end section of the associated guide rod.

Some or all of the guide rods of the guide rod arrangement are thus connected with one of their ends to a fixed location with respect to the frame of the reel unit and have at the other end the second end section, which is freely movable without connection and therefore to a limited extent. Three or more such guide rods with an elastically deflectable second end section can be provided. If an elongated workpiece, guided by the workpiece guides, engages the individual free ends of these guide rods, the free end sections of these guide rods tend to be deflected at least radially inwards towards the reel axis as the tensile force on the workpiece increases, contrary to the restoring forces that develop. On the other hand, if the tensile force decreases, the free ends of these guide rods tend to move radially outwards under the influence of restoring forces.

Such a one-sidedly connected guide rod therefore functions in a similar way to a one-sidedly clamped, otherwise self-supporting cantilever, the free end of which is more or less elastic depending on the forces acting on it in the transverse direction. is bent in the radial direction. The forces or their radial components transmitted from the guided workpiece via the workpiece guides to the free end sections of such guide rods can cause correspondingly directed deformations of these guide rods and/or deflections of these guide rods. Their extent is a measure of the size of the component of the attacking forces acting in the radial direction.

In comparison to a conventional solution with a single reel arm, a deflection distributed over several points on the circumference with a smaller deflection of the second end sections results in a larger storage path for the workpiece material. In addition, by distributing the deflection over several guide rods or their workpiece guides over the entire circumference of the reel, the risk of kink formation in the workpiece material can be reduced.

According to a further development, it is provided that the guide rod arrangement has four or more guide rods, the number of guide rods preferably being in the range of five to ten. If these conditions are met, a relatively uniform distribution of force over the individual guide rods of the guide rod arrangement can be achieved. In this way, acceleration peaks acting on the workpiece can be compensated particularly well in the manner of a buffer memory, especially before they are transferred to the reel. Experience has shown that five, six or seven guide rods, preferably more or less evenly distributed over the circumference, are a good compromise between a sufficiently uniform distribution of guide points over the circumference of the reel on the one hand and kink-free guidance of the guided workpiece material on the other.

The guide rods of a guide rod arrangement can extend parallel to the reel axis. It has proven to be particularly useful if the guide rods are oriented at an acute angle to the reel axis, which can be in the range of 10° to 20°, for example. If possible, the connection points should be closer to the reel axis than the free ends of the guide rods, so that a force acting radially inwards deflects the guide rods into an orientation that is closer to the parallel orientation.

Experiments by the inventors have shown that the guide rods should be neither too long nor too short. According to a further development, it is provided that a ratio between the free length of the guide rods and the radial distance between the frame-fixed connection points of the guide rods and the reel axis is in the range of 0.5 to 2. The free length of a guide rod is measured between the connection point fixed to the frame and the free end of the guide rod. It is usually particularly favorable if the ratio between the free length and the radial distance is in the range between 0.8 and 1.2, so that a guide rod should be approximately as long as the radial distance between the connection point and the reel axis. This makes it possible to achieve good compromises between the most compact design of the reel unit and sufficient spring action.

On the one hand, the smallest possible radial distances between the connection points and the reel axis are advantageous for an overall compact lateral dimension of the reel unit. On the other hand, the area centered around the reel axis can then become too narrow to accommodate a coil. If, on the other hand, the free length of the guide rods is approximately in the order of magnitude of the radial distance between the connection points and the reel axis, then while the external dimensions of the reel unit are still compact, there is, on the one hand, enough space to accommodate a coil in the area around the reel axis and, on the other hand, the guide rods have a deflectable free end section sufficient length to show significant deflections and/or deformations even when the forces are not too great.

In the embodiment of the device, the workpiece guides of the guide rods are in a neutral position within a circular ring. The neutral position refers to the position of the guide rods that exists without deflection of the guide rods. In other words, the guide rods are in their neutral position when they are essentially free of stress caused by the workpiece being pulled in. The circular ring is preferably defined by two concentrically arranged circles, with a radius of the inner circle being 3 to 20 percent, in particular about 10 percent, smaller than the radius of the outer circle. In this way, buckling of the workpiece can be counteracted.

If each guide rod has at least one workpiece guide and guide rods are distributed more or less in a ring shape around the reel, a longer section of the workpiece material running more or less in the shape of a circular arc can be guided and held by the individual workpiece guides of the guide rods, so that the workpiece material can form at least one loop . A loop in the sense of this application is formed in particular when the workpiece material is guided around the reel axis over 360° or more.

A guide rod arrangement can serve as a loop storage for the workpiece material, in which at least one loop of the workpiece material is held by the workpiece guides of the individual guide rods. The reel unit thus has a loop storage, which means that the free workpiece length between the removal point on the workpiece coil and the feed device can be significantly longer than the distance between the reel unit and the forming device. Such a loop memory can - as already indicated above - also serve as a buffer memory in order to decouple the acceleration processes on the feed device from the workpiece supply.

In this case, the loop storage is arranged essentially concentrically to the reel axis. This means that the components of the loop storage that come into contact with the workpiece (i.e. the workpiece guides on the guide rods) are arranged in such a way that at least one loop can be formed, which is arranged more or less concentrically to the reel axis. With a vertical reel axis, this loop storage is preferably arranged at a level above the area of the reel in which the recorded coil lies.

In some embodiments, several of the guide rods, in particular all of the guide rods, have a first workpiece guide and at least one second workpiece guide in the second end section. Thus, more than one loop of the workpiece material can be formed on the workpiece guides of the guide rods of the guide rod arrangement, for example 1.5 loops or two loops or 2.5 loops can be formed. This allows the guide rod arrangement to provide an even greater storage length of the loop storage.

The reel axis is preferably oriented in the vertical direction. Gravity then affects all guide rods in the same way, so that there is no fear of asymmetry in function due to gravity. In principle, the reel axis can also be oriented obliquely to the vertical, or possibly also horizontally.

A workpiece guide can, for example, be in the form of a closed eyelet or an eyelet that is still open at one point. This can be made from the material of the guide rod integrally with the be shaped like this. It can also be an eyelet that can be produced separately and can be subsequently attached to the second end section, for example by screwing or welding.

A workpiece guide can also include a deflection roller, which preferably has a circumferential groove on its circumference in which the guided and deflected workpiece can be guided laterally. With a deflection roller, particularly low-friction workpiece guidance is possible.

The roller can, for example, be rotatably mounted concentrically to the guide rod. The workpiece guide can also be part of a separate assembly which is attached to the second end section. The workpiece guide can, for example, have a deflection roller (possibly with a circumferential groove) which is mounted on an axle piece which is formed on a support or arm that can be attached to the guide rod. The workpiece guides can be attached at different heights. Using workpiece guides arranged helically in the vertical direction, e.g. deflection rollers, a wire or other elongated workpiece can be brought to the machine feed height more slowly and evenly if necessary. Overall, this means that the processing of the workpiece material and the adaptation of the memory can be carried out more homogeneously (at best with minor fluctuations).

There are different options for connecting the individual guide rods with their first end section on the frame side to a component that is fixed to the frame, in particular screwed or welded. According to a further development, guide rods are firmly connected to the component fixed to the frame. The ability to deflect some or all of the guide rods between the connection point and the workpiece guide essentially results from the elastic deformability or the rigidity of the area between the connection point and the workpiece guide. Such a guide rod can have a corresponding elastic flexibility or a corresponding rigidity over its entire length.

In some embodiments, some or all of the guide rods are essentially made of spring steel and are structurally designed so that the optimal rigidity or elastic flexibility is present with regard to the forces that occur.

It is also possible to form a separate spring section between the connection point within at least one guide rod, which is more easily deformable compared to the adjacent sections and makes a significant contribution to the elastic flexibility of this guide rod. An elastically flexible section can be designed, for example, in the manner of a coil spring. It is also possible to insert an elastically deformable section made of a rubber-elastic material in the area of the first end section. If a separate, elastically deformable section is inserted within such a guide rod, the rest of the spring rod can have a significantly higher rigidity. In the embodiment variants mentioned, the required elastic flexibility between the connection point and the workpiece guide is provided by the design of the guide rod itself with a deflectable free end section.

It is also possible to connect a guide rod to a component fixed to the frame via a swivel joint. In this case, the guide rod itself can have a very high rigidity. The elastic compliance and the required restoring forces can then be achieved via a spring arrangement, which acts on the pivotable guide rod on the one hand and on the component fixed to the frame on the other hand. The arrangement can be such that, due to the separate spring elements, a guide rod is in a neutral position in the absence of external forces in the area of the workpiece guide, from which it is deflected accordingly when forces are applied to the workpiece to be guided.

A feeding device of the type described here should preferably be able to be used not only for a specific type of workpiece, but for a certain spectrum of workpieces with different properties. For example, workpieces such as wires, pipes or strips of different thicknesses and/or different material properties should be able to be picked up and fed equally reliably. With a view to universal usability for workpieces with different properties from a certain range of applications, in some embodiments it is provided that some or all of the guide rods are assigned a stiffness adjustment device for adjusting the effective stiffness of the guide rod. Preferably, the stiffness adjustment device should be designed so that a continuous adjustment of the effective stiffness is possible within a certain setting range. The term “effective stiffness” essentially refers to the resistance to elastic deformation that a guide rod offers to the workpiece to be guided. The effective stiffness depends on both the elasticity of the material of a guide rod and the geometry of the guide rod Overall construction comprising the guide rod, which also determines the deformability.

In some embodiments, the stiffness adjustment device for each of the relevant guide rods has a support rod arranged at a distance next to it, which is also connected to the component that carries the respective guide rod. A displaceable connecting element connects this guide rod and the support rod arranged next to it. By moving the connecting element in the longitudinal direction of the rod, it is possible to continuously adjust the support length over which the guide rod is supported by the support rod and thus becomes more resistant to external forces and, accordingly, how long the remaining deformable length remains until the workpiece guide. The connecting element can, for example, be manually moved when setting up the feed device for a new workpiece material and fixed in the desired position by means of a clamping screw or the like.

In other embodiments, which have a separate, elastically deformable spring section in the area of the first end section, a stiffness adjustment device can be realized by providing a sleeve which can be displaced along the guide rod and which can also be guided over the spring section. Depending on the length over which the sleeve encloses the spring section, the deflection of the guide rod can be limited to a greater or lesser extent. This also allows the effective rigidity of a guide rod to be infinitely adjusted.

In the embodiment of the device, the reel is designed as an active reel. This means that the reel can be driven by means of a reel drive, whereby the speed of reel rotation can be variably specified via control signals from a control device. The rotation of the reel can be controlled depending on the conditions of the workpiece material. For this purpose, the device has a workpiece state detection device for detecting workpiece states that can be influenced by the operation of the feed device. In particular, the workpiece condition is influenced by which movement profile, i.e. with which accelerations and/or speeds, the workpiece material is drawn in in each phase of processing. The workpiece state detection device generates state signals that represent the workpiece states. The guide rod arrangement is a functional component of the workpiece condition detection device. The control device is configured to control the reel drive depending on the status signals. This makes a controlled workpiece removal operation possible, in which the dynamics of the rotation of the reel can automatically adapt to the dynamics of the processes during the workpiece material intake.

Preferably, the workpiece condition detection device has at least one rod condition detection sensor.

Depending on the design of the guide rods, different rod condition detection sensors can be used to generate corresponding status signals. In particular, the rod state detection sensor serves to detect a rod state of the at least one guide rod with a deflectable free end section.

For example, a deflection sensor can be used as a bar state detection sensor. This can be arranged so that a deflection of a guide rod can be measured at a specific position at a distance from the connection location of the first end section. Using a deflection sensor, the deflection of the guide rod in this area can be determined in relation to a reference position (for example a reference position in the force-free state). The deflection sensor preferably works without contact and can be designed, for example, as a distance sensor. A distance between the current position and the reference position is then a measure of the forces leading to the deflection that act on the guide rod in the area of the workpiece guide.

Alternatively or additionally, a strain sensor attached to the deflectable guide rod can be used as a rod condition detection sensor, for example in the form of a strain gauge. This can, for example, be attached near the connection point within the first end section on the guide rod on the side that comes under tensile stress when stronger forces act on the workpiece. Thus, conclusions can be drawn about the deflecting forces acting in the area of the free second end section based on the extent of the deformation in the area of the strain sensor.

Alternatively or additionally, it is also possible to use at least one force sensor that measures the forces acting on a guide rod to deflect or deform it.

Alternatively or additionally, a rotary encoder or a displacement sensor can be used to record the rod condition.

It is also alternatively or additionally possible to use one as a bar state detection sensor To use an acceleration sensor that detects an acceleration of the second end section during its deflection.

It is also possible to mount a guide rod in the area of its connection to a component fixed to the frame so that it can pivot about a pivot axis and, for example, to pretension it into a zero position using spring tension, from which the spring rod is then pivoted when the forces caused by the guided workpiece are applied. The extent of the pivoting can be detected using a rotary encoder, with the angle of rotation then being a measure of the forces acting in the area of the workpiece guide.

According to a further development, a bar state detection sensor is designed as a proportional sensor, which can generate a state signal proportional to the extent of the state variable for each value of the detected state variable within a detection range lying between a first final value and a second final value. This means that a corresponding status signal can be generated continuously for each status within the detection range. As a result, a particularly quiet reel run can be achieved with possibly only gradual changes in speed or only weak accelerations.

There are embodiments in which all guide rods can be deflected elastically. However, this is not mandatory. In some embodiments, there are one or more guide rods in which the second end section, i.e. the free end section, is essentially not deflectable. In particular, the second end sections of two immediately adjacent guide rods cannot be deflected in this way. “Substantially non-deflectable” is understood to mean that the second end section in question is hardly or not deflected during operation of the device, i.e. it remains essentially stationary even when external forces are applied. For this purpose, the relevant guide rod and its frame-side connection can be designed to be comparatively rigid or rigid compared to the at least one deflectable guide rod. Non-deflectable guide rods are also referred to here as essentially undeflectable.

In an embodiment of the device, a guide rod carrier which can be handled separately from the frame of the reel unit is provided and which carries all the guide rods, the first end sections of the guide rods being connected to the guide rod carrier and the guide rod carrier being detachably connectable to the frame. The guide rod carrier can, for example, be a ring-shaped, closed carrier frame, the free inner diameter of which is so large that the carrier frame can enclose the outside of the reel unit with the largest coil that can be attached to it. The support frame can, for example, have a polygonal shape and consist of straight individual parts assembled at angles, which form a torsion-resistant overall arrangement with a low overall weight.

The guide rod carrier with the guide rods attached or attachable to it can be available as a retrofit kit in order to convert conventional reel units relatively inexpensively into a configuration according to the invention without great technical effort.

One aspect of the invention relates to such a retrofit kit. The retrofit kit can be used to retrofit a conventional generic device for feeding an elongated workpiece. The retrofit kit includes a guide rod carrier that supports a guide rod assembly with three or more guide rods. Each of the guide rods extends from a first to a second end section substantially parallel or at an acute angle to a main axis of the retrofit kit. The first end section is connected to a support-fixed connection point on the guide rod carrier and the second end section of some or all of the guide rods can be deflected in an elastically resilient manner at least radially to the main axis. The second end section has a workpiece guide for guiding and/or deflecting the workpiece. The guide rod carrier can be mounted on the frame of the reel unit in such a way that the main axis runs coaxially to the reel axis and the guide rods are arranged distributed around the reel. By mounting the retrofit kit on the frame of the reel unit, a device described above can be formed, to the frame of which the guide rod carrier of the retrofit kit is firmly attached. Under this condition, the advantages listed above also apply mutatis mutandis to the retrofit kit or a device retrofitted with the retrofit kit.

The guide rod carrier of the retrofit kit can be designed as a ring-shaped closed unit, for example with a polygonal, for example hexagonal, outline. There can be one guide rod per corner of the outline. The guide rods can be connected to the corners or between the corners on the sides of the guide rod support.

With regard to the number of guide rods, the arrangement of the workpiece guides and the other design of the guide rod arrangement Please refer to the description above.

The retrofit kit can also have components of a workpiece condition detection device of the type described in this application.

The invention also relates to a forming machine which has a feed device that can be operated at varying feed speed for pulling in an elongated workpiece and for conveying the workpiece to a tool area of the forming machine, the forming system having a device according to the invention and described above for feeding an elongated workpiece. The advantages explained above are therefore also transferred to the forming machine according to the invention.

BRIEF DESCRIPTION OF DRAWINGS

• 1 zeigt eine Gesamtansicht einer Drahtverarbeitungsanlage mit einer Umformmaschine in Form einer Federwindemaschine sowie einer in Materialflussrichtung vorgeschalteten Vorrichtung zum Zuführen des langgestreckten drahtförmigen Werkstückmaterials gemäß einem Ausführungsbeispiel;
• 2 zeigt eine vergrößerte Darstellung der Zuführvorrichtung;
• 3A bis 4B illustrieren einige Möglichkeiten, die effektive Steifigkeit von Führungsstäben stufenlos zu verstellen;
• 5 zeigt in schematischer Perspektivdarstellung eine weitere Zuführvorrichtung, die mit einem Nachrüstsatz nachgerüstet ist.

Further advantages and aspects of the invention result from the claims and from the description of exemplary embodiments of the invention, which are explained below with reference to the figures.

• 1 shows an overall view of a wire processing system with a forming machine in the form of a spring winding machine and an upstream device in the material flow direction for feeding the elongated wire-shaped workpiece material according to an exemplary embodiment;
• 2 shows an enlarged view of the feed device;
• 3A until 4B illustrate some ways to continuously adjust the effective stiffness of guide rods;
• 5 shows a schematic perspective view of another feeding device that is retrofitted with a retrofit kit.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The schematic 1 shows an overall view of a wire processing system 100 according to an exemplary embodiment. The wire processing system 100 is set up to produce a large number of similar shaped parts in the form of helical springs, in particular compression springs or tension springs, from an elongated workpiece 110 in the form of a metallic wire in a computer numerically controlled manufacturing process.

The wire processing system 100 comprises a forming machine 200 in the form of a spring winding machine 200 and a device 300 connected upstream in the material flow direction for feeding the elongated wire-shaped workpiece material to the forming machine 200. The device 300 is also referred to briefly as the feed device 300 in this application.

The forming machine 200 includes a feed device 210, which is connected to the control unit 290 of the forming machine 200 and, under the control of an NC control program, wire fed by the feed device 300 into the tool area 220 equipped with forming tools (one or more). Forming machine 200 promotes. By means of the forming tools downstream in the material conveying direction, the supplied wire is formed into a coil spring or (in other forming machines) into another molded part. After the forming operation has been completed, the finished molded part is separated from the supplied wire under the control of the NC control program using a cutting device (not shown). This process is repeated cyclically for each molded part to be manufactured.

The feed of the wire to the tool area 220 or the feed of the wire through the feed device 210 should take place according to a speed profile specific to the manufacturing process with a feed speed that varies over time. The feed device 210 preferably has at least one pair of feed rollers, which has two feed rollers which are arranged with axes of rotation parallel to one another and can be driven in opposite directions via a controlled drive. Two or more pairs of feed rollers that can be operated synchronously are often provided in order to be able to transfer the feed forces to the workpiece material in a way that is gentle on the material and without significant slippage. With their profiled peripheral surfaces, the feed rollers limit a feed gap for feeding the workpiece through. By controlling the rotation speed and direction of rotation of the feed rollers, the feed speed and the feed direction of the material to be processed can be specified.

An insufficiently well-controlled supply of wire can lead to significant quality problems in spring winding machines, for example. In these forming machines, unlike wire bending machines in the bending process, the forming force on the forming tools is applied directly by the feed rollers of the feed device 210 in order to press the workpiece against a winding tool and thus advance the winding process. During this process, any slippage on the feed rollers of the feed device 210 can directly affect the quality of the end product impact. In highly dynamic spring coil machines, the slip on the retraction device 210 can, in unfavorable cases, amount to several percent of the total retraction length, which would result in the springs produced being too short.

One task of the feed device 300 can be to feed the wire to the feed device of the forming machine 200 as accurately as possible at any time at the speed required at that time.

A workpiece supply with a large length of wire to be processed is kept in the form of a coil 112 in a reel unit 380 of the device 300. In this example, the reel unit 380 has a reel 310. The reel 310 is in the examples 1 , 2 and 5 arranged with a vertical reel axis 312. The wire is then gradually withdrawn from the circumference of the coil 112 in the direction of subsequent devices while rotating the reel 310 or the coil 112.

The coiler unit 380 is a separate assembly from the forming machine 200, which is used to hold the coil 112 made of workpiece material. The reel unit 380 comprises a frame 320, which has, for example, a base plate with adjustable feet for setting up on the hall floor and storage devices on the base plate for storing the reel 310. The reel 310 can rotate indefinitely.

The reel 310 is only shown schematically in the figures. In its lower part, it includes a plate-shaped or plate-shaped collar receptacle 314, on which a wire collar or another workpiece collar can be placed. Not shown are four radially infinitely adjustable, upwardly projecting stanchions with which the coil can be centered after it has been placed on the coil holder. After placing the coil, an upper end element 316 in the manner of a wheel with radial spokes is placed over a centering rod 317 arranged coaxially to the reel axis 312 and clamped in a certain height position.

During operation of the forming machine 200, the wire is then gradually withdrawn from the circumference of the wire coil 112 using its feed device 210.

The mechanical components that enable the workpiece 110 to roll off the reel 310 as uniformly as possible include a guide rod arrangement 410, which comprises, for example, six guide rods 420 which are arranged at substantially uniform circumferential distances in an annular or circular arrangement around the reel 310 . Each of the guide rods 420 has a first end section 422, which is firmly connected to the base plate of the frame 320 in the area of a connection 424, and at the opposite end a second end section 425, which is not connected to the base plate. In the present case, the second end section 425 of each of the guide rods 420 is freely movable within certain limits relative to the base plate. The limits are given by the elastic flexibility or rigidity of the guide rod 420 and its corresponding elastic deformability. In the absence of external forces, the guide rods 420 are straight. They are connected in such a way that their longitudinal axes form an acute angle of approximately 10° to 20° with the reel axis 312, in such a way that the guide rods 420 are inclined outwards in the radial direction from the connection points 424 with respect to the reel axis 312. The connection points 424 of the guide rods 420 are arranged at a radial distance from the reel axis 312. A ratio of this radial distance to the free length of the guide rods 420 is, for example, in the range of 0.5 to 2. Each of the guide rods 420 carries in its free second end section 425 remote from the frame 320 two workpiece guides 430 which are axially offset relative to the length of the guide rod 420, which belong to the guide rods 420 as components that come into contact with the workpiece and are designed in such a way that the passing wire can be held and guided near the free end of the guide rod 420 using the workpiece guides 430.

In the example case, each of the workpiece guides 430 has a deflection roller 432. The deflection roller 432 is mounted on the second end section 425 of a guide rod 420 using a boom 434. The boom 434 has a boom arm which has a through hole in one end region for passing the end section 425 of the guide rod 420 through, and at a distance therefrom in the other end region an axle piece on which the deflection roller 432 is rotatably mounted. The axis of rotation of the deflection roller 432 runs essentially parallel to the longitudinal direction of the second end section 425 or the unbent guide rod 420.

The workpiece 110, here the wire, is guided in the area between the deflection roller 432 and the guide rod 420 on the radially outer part of the circumference of the deflection roller 432, which has a circumferential groove to prevent the guided wire from slipping in the axial direction.

For example, on each guide rod 420 there are two axial ones in its second end section 425 deflection rollers 432 that are offset from one another are mounted, the longitudinal position of which can be continuously adjusted on the guide rod 420 when setting up the machine and fixed using clamping screws or the like.

Like in the 1 , 2 and 5 clearly visible, the wire is not guided directly from the circumference of the coil 112 towards the forming machine 200. Instead, on the way to the forming machine 200, a loop storage 440 is interposed, which in the present case can hold two complete, essentially circular loops of the workpiece material before it is led to the forming machine 200. The essentially circular course of the workpiece material within the loops is determined by the positions of the workpiece guides 430 at the rod ends. The deflection rollers 432 are arranged at different heights so that they prescribe a helical course of the wire from the coil 112 at the lower end to the level of the feed device at the upper end.

The guide rods 420, which are fixed to the frame with their first end sections 422, are designed so that they are not rigid and immovable compared to the forces typically exerted by the workpiece material, but on the contrary have a certain rigidity on the one hand, but on the other hand an elastic bending under the influence of forces of the workpiece material allow workpiece guidance. In this case, the guide rods 420 are each made of spring steel and are relatively thin relative to their rod length (between the two ends). A ratio between the maximum diameter and rod length of the spring rods can, for example, be in the range from 0.005 to 0.02. The length of the spring bars between the connection point 424 and the free end is approximately in the range between 80% and 120% of the radial distance of the connection points 424 from the reel axis 312.

This creates a loop storage 440 which, on the one hand, has a relatively high storage capacity (approximately twice the circumference of a recorded loop) and, on the other hand, due to the elastic flexibility of the guide rods 420, it responds to changes in the tensile stress caused by the feed device by deflection of the free ends of the guide rods 420 can react to change the storage volume of the loop memory 440 within certain limits. The essential component of the deflection is oriented radially to the reel axis 312, since the wire wants to pull the guide rods 420 inwards. In addition, the guide rods 420 can be deflected laterally, i.e. in the direction of an adjacent guide rod 420, in an elastically resilient manner.

For example, if the tensile force F exerted by the feed device 210 is significantly increased, all free ends of the guide rods 420 are pulled essentially radially inwards towards the reel axis 312 by the workpiece material under tension, so that tension compensation takes place and the tensile stress peaks are not at the Reel 310 arrives, which can continue to rotate at a relatively constant speed. On the other hand, if the pulling speed decreases after a phase of relatively high pulling speed, the radially inwardly acting forces at the ends of the guide rods 420 are reduced, so that they are deflected outwards, reducing their elastic tensions, which in turn largely decouples the reel 310 from the feed in terms of tension can be.

Within the guide rod 420, for example, a separate spring section 421 is formed, which is more easily elastically deformable compared to adjacent sections of said guide rod 420. “Easier to be elastically deformed” means, for example, a locally reduced stiffness in the area of the spring section 421 compared to the neighboring sections. If the material of the guide rod 420 is homogeneous, this can be achieved, for example, by locally changing the moment of inertia related to the bending axis oriented perpendicular to the deflection. To locally reduce the elastic deformability, the spring section 421 can be designed separately and/or designed in the manner of a coil spring and/or made of a rubber-elastic material.

Due to the elastic flexibility provided by the design and the possibility of reversible deflection of the free end sections 425 due to radial forces acting on them, the guide rod arrangement 410 has a certain sensitivity, i.e. a construction-related relationship between the magnitude of the forces leading to the deflection in the area of the workpiece guides 430 and the forces caused thereby radial deflections. The sensitivity is due to the effective rigidity of the relevant guide rod 420.

In order to be able to use the reel unit 380 with good efficiency and/or sufficiently sensitive control for processing workpiece materials of different strengths, some exemplary embodiments are equipped with special devices that allow the effective stiffness to be adjusted relatively quickly and easily the guide rod assembly 410 enable. These devices preferably allow a continuous adjustment of the effective stiffness.

In the 3A , 3B and 4A, 4B, two structurally relatively simple, robust and yet effective options for setting the sensitivity are explained as examples. The sensitivity, ie the response behavior of the workpiece state detection device 400, to different workpiece tensions in the guide rod arrangement 410 is essentially based on the effective rigidity of the guide rods 420, which are firmly connected on one side, i.e. on the resistance of the free rod ends to deflection under the influence of radial forces. This effective stiffness of the guide rods 420 can be adjusted very easily and manually using suitable stiffness adjustment devices 460.

In the variant 3A and 3B the stiffness adjustment device 460 includes a support rod 462, which is firmly connected to the same connection unit at some distance next to its associated guide rod 420 radially outside of its connection point 424. The two rods are connected via a connecting element 464, which has two axially parallel through holes for the passage of the guide rod 420 or the support rod 460. The connecting element 464 can be clamped at different axial positions of the guide rod 420 or the support rod 462 by simply turning a clamping lever and released just as easily. If the connecting element is attached relatively close to the connection point 424 ( 3A) , the effective stiffness of the guide rod 420 will essentially correspond to that of a guide rod 420 without an associated support element. If, on the other hand, the connecting element 464 is pushed in the direction of the second end section 425 of the guide rod, so that a larger length of the guide rod 420 is firmly connected to the parallel support rod 460, the free length of the guide rod 420 available for bending is reduced, so that its resistance to deflection in the area of the workpiece guide 430 increases.

In the variant of 4A and 4B For example, a guide rod 420 with a rectangular cross section is provided. The guide rod 420 is not made of the same rod material all the way up to the connection point 424, but rather has a spring section 421 in the manner of a helical spring in the first end section. The deflection at the distant second end section 425 does not result (exclusively) from the flexibility of the rectangular guide rod, but to a large extent from the elastic bendability in the area of the spring section 421. The stiffness adjustment device 470 here includes a support sleeve 474, which is guided axially displaceably on the rectangular cross section of the guide rod 420 and can be placed more or less far over the spring section 421. When configuring in 4A the support sleeve 474 leaves most of the spring section free, so that its entire length is available for bending and the guide rod 420 has a softer characteristic overall. On the other hand, if the support sleeve 474 is found in the direction of the connection point 424 in such a way that only a shorter section of the spring section remains bendable ( 4B) or even the spring section lies within the support section of the support sleeve 474 over its entire length, this results in a significantly higher effective rigidity.

Some advantages of the exemplary embodiments compared to conventional feed devices are mentioned again below in summary.

The deflection over the circumference of the reel 310 results in a larger wire storage path with smaller deflections of the guide rods 420. In addition, by distributing the deflection over several arms or rollers over the entire circumference, the risk of kink formation is reduced. The deflection rollers 432, which are arranged helically in the vertical direction, also bring the wire to the machine feed height more slowly and more evenly. Overall, the unwinding of the wire and the adjustment of the memory are more homogeneous.

Three or more guide rods 420 are used over the circumference of the reel 310, for example four, five, six, seven or eight. Instead of a movable bearing, the deflection is realized via the spring action of guide rods, which act as spring rods. At the free end of each guide rod, deflection roller combinations can be used, and if necessary also eyelets.

Some or - as in the present case - all of the guide rods 420 are firmly connected with their frame-side first end section 422 to a component fixed to the frame. Alternatively, at least one of the guide rods 420 can be connected to a component fixed to the frame via a pivot joint, with a spring arrangement being provided. In this alternative, not shown in the figures, the spring arrangement engages on the one hand on the pivotable guide rod 420 and on the other hand on a component fixed to the frame. The arrangement is designed in such a way that a guide rod 420 is held in a neutral position by the spring arrangement in the absence of external forces in the area of the workpiece guide 430, from which it is at The action of forces on the workpiece 110 to be guided is deflected with deformation of the spring arrangement.

The reel 310 is shown in the example 5 designed as a passive reel 310. The passive reel 310 is freely rotatable and is set in rotation about the reel axis 312 only by removing the workpiece 110. A reel drive is shown in the example 5 not provided. In contrast, in the example according to the 1 and 2 the reel 310 is designed as an active reel. As already explained above, the active reel 310 can be actively rotated by means of a reel drive 315. The reel drive can, for example, comprise a servo motor which is connected to the output of the control device 390, which in the example is mounted as part of the reel unit on the base plate of the frame 320. The reel 310 can be driven to rotate about the reel axis 312 by means of a reel drive 315 that can be controlled by the control unit 390.

The effects of changes in workpiece tension at the feed on the area of the guide rod assembly 410 are as follows 1 and 2 detected at the reel unit 380 by means of suitable sensors, transmitted to the control device 190 by means of suitable status signals and this then controls the reel drive 315 so that the reel 310 is rotated at any time at a rotational speed that systematically avoids the build-up of voltage peaks on the reel.

In the example case of 1 and 2 the device 300 has a workpiece condition detection device 400, the component of which is the guide rod arrangement 410. In addition, the workpiece condition detection device 400 has a non-contact distance sensor 470, which is connected to the control unit 390 and located radially outside of the in 2 Guide rod 420, which can be seen on the right, is arranged fixed to the frame so that the distance sensor 470 can continuously measure the radial distance AB between a reference plane of the distance sensor and a reference plate RP attached to the second end section. The distance measurement can be carried out optically or acoustically, for example. The distance signals are representative of the voltage state of the wire stored in the memory and are transmitted to the control device 390 and evaluated there.

The distance AB is a sensitive measure of the workpiece clamping. If the workpiece 110 wound into loops is not under tension, all guide rods 420 are in their force-free configuration, in which they are not elastically bent, but are tension-free and straight. In this force-free configuration, the guide rods 420 are in a zero or neutral position. When the guide rods 420 are in their neutral position, the workpiece guides 430 of the guide rods 420 are arranged, for example, within a circular ring. The circular ring is delimited by two concentrically arranged circular lines, with a radius of the inner circular line being 3% to 20%, in particular approximately 10%, smaller than the radius of the outer circular line. When the workpiece tension increases, i.e. when workpiece material is drawn more strongly towards the forming machine 200 than it can be unrolled or tracked by the reel 310, the loops in the loop storage 440 contract, as a result of which the free ends of the guide rods move radially inwards via the workpiece guides to be pulled. This increases the distance AB. By measuring the distance, status signals can be generated that are representative of the workpiece status, in particular for the workpiece tension, between the forming machine 200 and the reel 310. The reel 310 is regulated by changing the distance. If a certain distance is exceeded, an emergency stop is triggered, which switches off the reel 310.

In order to be able to control the reel drive 315 in such a way that the reel can deliver the wire smoothly and continuously despite changing feed speeds and possible temporary standstill of the feed, according to 1 and 2 a workpiece state detection device 400 is provided, which can automatically detect the workpiece states caused or influenced by the operation of the feed device and generate corresponding state signals representing the workpiece states, which are then processed by the control device 390 in order to control the reel drive 315 depending on the state signals. The guide rod arrangement 410 is part of the workpiece detection device 400.

The workpiece condition detection device 400 includes at least one rod condition detection sensor. Different sensor concepts can be used. The bar state detection sensor can have a deflection sensor, which preferably works without contact and/or is designed as a distance sensor 470. Alternatively or additionally, the rod condition detection sensor can have a strain sensor, in particular with a strain gauge, which is attached to a radial outside of a guide rod in the region of the first end section. Alternatively or additionally, a force sensor can be used Rotary encoder, a displacement sensor and / or an acceleration sensor may be provided.

To control the reel motor, in an embodiment not shown, another rod is coupled to one of the guide rods 420. This merely transmits the movement of the coupled part of the guide rod 420 to a rotation angle sensor or a displacement sensor, which can be attached to the lower end of the guide rod 420. In this way, an indirectly acting bar state detection sensor can be realized.

In the embodiment according to 5 There is a guide rod carrier 450, which can be handled separately from the frame 320 of the reel unit 380. The guide rod carrier 450 is releasably attached to the frame 320, so that in the present case it forms a component that is fixed to the frame. The guide rod carrier 450 carries all the guide rods 420. The first end sections 422 of the guide rods 420 are connected to the guide rod carrier 450. The guide rod carrier 450 can be designed as a carrier frame. The guide rods 420 can be connected to the frame 320 by means of the guide rod carrier 450.

The feed device after 5 is retrofitted using a retrofit kit. The retrofit kit is used to retrofit a corresponding device without a guide rod arrangement. A device to be retrofitted can essentially correspond to the above feed device 300 without guide rod arrangement 410.

The guide rod arrangement 420 can now be attached to the device to be retrofitted in a particularly simple manner, in particular reversibly, using the retrofit kit. For this purpose, the retrofit kit of the example includes a separate assembly with a guide rod carrier 450, which is designed as a hexagonal frame and carries a guide rod arrangement 410 with six guide rods 420. Each of the guide rods 420 extends from a first end section 422 to a second end section 425 essentially parallel or at an acute angle to a main axis 480 of the retrofit kit. The first end section 422 is connected to a carrier-fixed connection point 424 on the guide rod carrier 450. The connection points are located in the middle between the corners. The second end section 425 of each of the guide rods can be deflected in an elastically resilient manner at least radially to the main axis 480 and has a workpiece guide 430 for guiding and/or deflecting the workpiece 110. The guide rod carrier 450 is mounted on the frame 320 of the reel unit 380 in such a way that the main axis 480 runs coaxially with the reel axis 312 and the guide rods 420 are arranged distributed around the reel 320. By mounting the guide rod carrier 450 on the frame 320 of the reel unit 380, the in 5 form the arrangement made.

In an embodiment not shown in the figures, the second end section 425 of at least one of the guide rods 420, for example two adjacent guide rods 420, is essentially not deflectable or undeflectable. For example, those guide rods 420 whose workpiece guides 430, starting from the reel 310, first and/or last come into contact with the workpiece 110 can be designed to be essentially undeflectable. These non-deflectable guide rods can, for example, be designed to be rigid and/or rigid in themselves and in their connection to the frame, so that the position of the workpiece guides in space practically does not change during operation, even when the acting forces change. A loop storage device can thus be formed whose inlet and outlet remain stationary during operation, which can contribute to a quieter feeding process.

Claims (22)

Device (300) for feeding an elongated workpiece (110) to a forming machine (200), which has a feed device (210) for pulling in the fed workpiece (110) and for conveying the workpiece (110) to a tool area (220) of the forming machine ( 200), comprising: a reel unit (380) for receiving a workpiece supply (112) in the form of a coil (112) made of workpiece material, the reel unit (380) having a frame (320) and a reel (320) carried by the frame (320). 310), which is rotatably mounted about a reel axis (312); characterized in that the reel unit (380) comprises a guide rod assembly (410) with three or more guide rods (420) distributed around the reel (310), each of the guide rods (420) being substantially parallel or at an acute angle to the reel axis (312) from a first end section (422) to a second end section (425), the first end section (422) being connected to a frame-fixed connection point (424) and the second end section (425) providing a workpiece guide (430). Guiding and / or deflection of the workpiece (110), the second end section (425) of some or all of the guide rods (420) being elastically deflectable at least radially to the reel axis (312). Device (300) after Claim 1 , characterized in that the guide rod arrangement (410) has four or more guide rods (420), the number of guide rods (420) preferably being in the range from 5 to 10. Device (300) after Claim 1 or 2 , characterized in that a ratio between the free length of the guide rods (420) and the radial distance from connection points (424) of the guide rods (420) to the reel axis (312) is in the range of 0.5 to 2. Device (300) according to one of the preceding claims, characterized in that the workpiece guides (430) of the guide rods (420) lie in a neutral position within a circular ring. Device (300) according to one of the preceding claims, characterized in that the reel unit (380) has a loop storage (440) which is arranged concentrically to the reel axis (312) in such a way that components of the loop storage (440) that come into contact with the workpiece, in particular the Workpiece guides (430) on the guide rods (420) are arranged in such a way that at least one loop of workpiece material can be formed, which is arranged more or less concentrically to the reel axis (312), the loop storage (440) preferably being designed to have more as a single loop of the workpiece material, in particular at least two loops. Device (300) according to one of the preceding claims, characterized in that several of the guide rods (420) in the second end section (435) have a first workpiece guide (430) and at least one second workpiece guide (430). Device (300) according to one of the preceding claims, characterized in that the reel axis (312) is oriented vertically. Device (300) according to one of the preceding claims, characterized in that a workpiece guide (430) has a closed eyelet or an eyelet that is laterally open at one point. Device (300) according to one of the preceding claims, characterized in that a workpiece guide (430) comprises a deflection roller (432), which preferably has a circumferential groove on its circumference for lateral guidance of the workpiece (110), the deflection roller (432) preferably is mounted on an axle piece which is formed on an arm (434) which can be attached to the guide rod (420). Device (300) according to one of the preceding claims, characterized in that some or all of the guide rods (420) are firmly connected with their frame-side first end section (422) to a component fixed to the frame. Device (300) according to one of the preceding claims, characterized in that some or all of the guide rods (420) consist essentially of spring steel. Device (300) according to one of the preceding claims, characterized in that a separate spring section (421) is formed between the connection point (424) and the second end section (425) within a guide rod (420), which in comparison to adjacent sections of the guide rod (420) is more easily elastically deformable, preferably a separate spring section (421) being designed in the manner of a helical spring and/or consisting of a rubber-elastic material. Device (300) according to one of the preceding claims, characterized in that a guide rod (420) is connected to a component fixed to the frame via a swivel joint and a spring arrangement is provided which acts on the one hand on the pivotable guide rod (420) and on the other hand on a component fixed on the frame , wherein the arrangement is designed in such a way that, in the absence of external forces in the area of the workpiece guide (430), a guide rod (420) is held in a neutral position by the spring arrangement, from which it falls under the influence of forces on the workpiece (110) to be guided Deformation of the spring arrangement is deflected. Device (300) according to one of the preceding claims, characterized in that some or all of the guide rods (420) are assigned a stiffness adjusting device (460, 470) for setting an effective stiffness of the guide rod (420), the effective stiffness preferably being infinitely adjustable is. Device (300) according to one of the preceding claims, characterized in that - the reel (310) can be driven by means of a reel drive (315) in response to control signals from a control device (390); - the device has a workpiece state detection device (400) for detecting workpiece states that can be influenced by the operation of the feed device (210) and for generating status signals representing the workpiece states, - wherein the workpiece state detection device (400) comprises the guide rod arrangement (410), and wherein the control device ( 390) is configured to control the reel drive (315) depending on the status signals. Device (300) after Claim 15 , characterized in that the workpiece condition detection device (400) has at least one rod condition detection sensor, which is selected from the group: a deflection sensor, which preferably works without contact and / or is designed as a distance sensor (470); a strain sensor, in particular with a strain gauge, which is attached to a radial outside of a guide rod in the region of the first end section; a force sensor; a rotary encoder or displacement encoder; an acceleration sensor. Device (300) according to one of the preceding claims, characterized by a, preferably annularly closed, guide rod carrier (450), which can be handled separately from the frame (320) of the reel unit (380) and which carries all guide rods (420), the first end sections (422) of the guide rods (420) are connected to the guide rod carrier (450) and the guide rod carrier (450) can be releasably connected to the frame (320). Device (300) according to one of the preceding claims, characterized in that the second end section (425) of at least one of the guide rods (420), in particular two adjacent guide rods (420), is essentially undeflectable. Retrofit kit for retrofitting a device for feeding an elongated workpiece (110) to a forming machine (200), which has a feed device (210) for pulling in the fed workpiece (110) and for conveying the workpiece (110) to a tool area (220) of the forming machine (300), wherein the device comprises a reel unit (380) for receiving a workpiece supply (112) in the form of a coil of workpiece material, the reel unit (380) having a frame (320) and a reel (320) carried by the frame (320), which is rotatably mounted about a reel axis (312); where the retrofit kit includes: a guide rod carrier (450) supporting a guide rod assembly (410) with three or more guide rods (420), each of the guide rods (420) being substantially parallel or at an acute angle to a main axis (480) of the retrofit kit of a first End section (422) extends to a second end section (425), the first end section (422) being connected to a support-fixed connection point (424) on the guide rod carrier (450) and the second end section (425) having a workpiece guide (430) for guidance and/or deflection of the workpiece (110), the second end section (425) of some or all of the guide rods (420) being elastically deflectable at least radially to the main axis (480), wherein the guide rod carrier (450) can be mounted on the frame (320) of the reel unit (380) in such a way that the main axis (480) runs coaxially to the reel axis (312) and the guide rods (420) around the reel (320). are arranged distributed. Retrofit kit Claim 19 , characterized in that the guide rod carrier (450) is an annularly closed unit. Retrofit kit according to one of the Claims 19 or 20 , further characterized by at least one of the following features: (i) the guide rod assembly (410) has four or more guide rods (420); wherein the number of guide rods (420) is preferably in the range of 5 to 10; (ii) a ratio between the free length of the guide rods (420) and the radial distance of connection points (424) of the guide rods (420) from the main axis (480) is in the range of 0.5 to 2; (iii) the workpiece guides (430) of the guide rods (420) lie in a neutral position within a circular ring; (iv) the guide rod arrangement (410) forms a loop storage (440), which can be arranged concentrically to the reel axis (312) in such a way that the workpiece guides (430) are arranged on the guide rods (420) in such a way that one or more loops can form workpiece material, which are arranged more or less concentrically to the reel axis (312); (v) a workpiece guide (430) comprises an eyelet or a deflection roller (432); (vi) the second end section (425) of at least one of the guide rods (420), in particular two adjacent guide rods (420), is essentially undeflectable. Forming system with a forming machine (200), which has a feed device (210) that can be operated at varying feed speed for pulling in an elongated workpiece (110) and for conveying the workpiece (110) to a tool area (220) of the forming machine (200), the forming system a device (300, 500) for feeding an elongated workpiece (110) to a forming machine (200), according to one of Claims 1 until 18 having.

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