EP1317975A1 - Device for producing stretched wire - Google Patents

Abstract

The appliance has two clamp devices (24,28) at a distance to each other. At least one device (24) is moveable through a stretching distance, and one device has a sensor to detect wire tension. A roller straightening machine (22) is located on the intake side, followed in advance direction of the wire, by a first roller advance (23), a first clamp device, a straightening section (32), a second roller advance, and a second clamp device. The first clamp device is located on a linear hydraulic power intensifier (25). The sensor is a pressure cell located on the stationary clamp device (28). A control unit adjusts the stretching length dependent upon wire tension.

Description

Technical field

The invention relates to a device for producing discontinuously stretched Wire with two spaced clamping devices, at least one by one Stretching length is movable. Furthermore, a system with such an upstream one Device claimed. In addition, the invention relates to methods for industrial Manufacture of discontinuously stretched wire.

State of the art

Mainly cold-rolled for structural steel mesh - so-called reinforcement mesh Steel wire (KR) is used, which is rolled and glowed in the steel mill then on a cold rolling mill in two stages to the desired nominal size is cold formed and ribbed. To shape the ribs, the wire is 15% to 25% deformed. Cold-formed wires have an increased strength compared to a wire rod but at the same time the material becomes more brittle and the elasticity decreases.

The most important parameters for structural steel and in particular for wires in structural steel mats are specified, for example, by the German DIN standard 488. Today's steel grades for structural steel consist of 100% scrap, primarily from motor vehicle scrap, and contain e.g. T. high alloy proportions of various foreign metals. As a result, the minimum values for the yield strength (R _e ) and the tensile strength (R _m ) required in the standards are achieved without any special effort. The cold forming to form the ribs is no longer required to achieve the prescribed strengths. However, it is becoming increasingly difficult to meet the requirements for the yield strength ratio (R _m / R _e ) and the elongation properties.

Hot-rolled and finned steel wire (WR) is rolled to its nominal size in the glowing state. In the last roll stand, ribbing is applied to the wire rod. In order to ensure that the yield strength (R _e ) reaches a higher value than is normally the case with a WR, the WR can be cold worked in an additional step. For example, the WR is cold worked by stretching.

There are currently three principal types of stretching that are used in practice divided into two main groups. The first main group is the continuous one Stretching, whereby a multi-axis or uniaxial tension is exerted on the wire becomes. Continuous stretching with multi-axis tension is the most common Process used to produce drawn wire. The wire is through the top and pulled underlying rollers, which in their axial alignment to each other are shifted so that the wire is drawn in a serpentine shape through these rollers. Combination systems are often used for this, which are the process of cold rolling and combine stretching. In the other method of continuous stretching uniaxial tension is applied to the wire. The wire is around a first Role in the opposite direction and via a second role, which is compared to the first role in The opposite direction of the pulling force is arranged, again in the pulling direction. In the view the reel is guided in the form of a lying 8. This procedure for Production of stretched wire is nowadays due to the high mechanical Effort and the lack of flexibility hardly applied.

Another possibility of discontinuous stretching with a uniaxial tension is assigned to the second main group. In this process the wire is combined stretched, straightened and cut. This is due to the so-called start-stop operation Processes much slower than continuous processes.

Presentation of the invention

The object of the invention is to create a device and the associated method, which is a discontinuous stretching of wire at high speeds and high Production security enabled.

The solution to the problem is defined by the features of claim 1. According to the Invention has an apparatus for the industrial manufacture of batch stretched wire two spaced clamping devices, at least one around one Return stroke is movable and at least one of them with a sensor for determining the Wire tension is equipped.

Industrial production is understood to mean production in quantities. This in Difference to test arrangements in which individual wires for the determination of Test results are processed and processed, for example in one Destruction test to check the maximum tensile strength.

The wire is delivered as a coil of wire in the coil. By one by the stretch Movable clamping device becomes the wire when stretching due to the plastic Deformation directed at the same time. There is no additional adjustment work as with Straightening wings or roller straighteners required. The sensor continues the wire tension is detected. The recorded values can be assigned to a wire section can be saved. Wire sections produced in the following are only checked for their final values. The stretching can be based on statistical Evaluations of the measured values are continuously adapted automatically. additionally a voltage threshold can be specified at which the one to be stretched Wire section is aligned absolutely straight.

The degree of stretching can thus be programmed continuously. This eliminates the need for adjustments the device if different production lengths are to be produced. Furthermore, the device does not have to be converted if the diameter of the wire changes become.

Each wire section is determined by the values recorded and saved by the sensor continuously checked. Fluctuations in material strength are observed during production recognized and the device can continuously adapt to the detected values processing material to be adjusted. At the same time, through the device Any material defects or rejects during production are recognized and qualitative inferior wires can be discarded or the further manufacturing process of Finished products are removed. This prevents none from being qualitative inferior wire sections with wire sections corresponding to the standards Structural steel mats are welded. The existing committee is concerned only individual wire sections and not entire structural steel mats. This does not result only to save material, but also to save a significant amount of time at Production of steel mesh.

Means for inserting or advancing the wire are preferably in Longitudinal wire direction provided. The wire rod is typical for industrial production introduced directly from the coil of wire rod into the device according to the invention. It can the wire rod can be shot into the device. With the means of insertion or feeding the wire during the production is also with one Exchange of the wire rod bundle guaranteed.

In a variant to this, cut and preferably pre-aligned wire sections preferably from a magazine or storage unit of the device according to the invention be fed transversely to the stretching direction. The wire sections fed in this way are stretched in the device and then processed further.

On the input side, the device is preferably provided with a roller straightener. This aligns the wire so far that it is facilitated by the device can be pushed through. The roles of the roller straightener are preferably slidably mounted so that the distance between the top and bottom rollers, preferably automatically controlled, adapts to the diameter of the wire. For one automatic control of the roles of the roller straightener can, for example, in The direction of insertion of the first, opposite rollers must be freely movable. Will the Inserted wire, the rollers move from their zero position according to the Diameter of the wire up or down. With a separate sensor can the distance between the first two roles recorded and the subsequent roles accordingly this distance can be positioned mechanically controlled. Further on Slidable rollers act a spring force, which is sufficiently large on the wire Press force exerts for the perfect guidance of the wire.

Instead of a roller straightener, the wire can e.g. B. straightened under straightening presses become. Another possibility to prepare the wire is with a straightening rotor Indicative stones. Furthermore, the device according to the invention can be a stretch leveler upstream, which straightens the wire before stretching. Can continue the roller straightener can be essentially replaced by any device which for example, at least pre-straightening the wire by rolling, drawing or pressing.

Are preferred in the device in the feed direction of the wire after Roller straightener a first roller feed unit, a first clamping device, a Straightening path and a second clamping device arranged. The approximately prepared one Wire is fed from the roll straightener through the first with the first roll feed unit Clamping device, the straightening section and the second clamping device passed through. After the two clamps hold the wire, at least through the a movable clamping device, preferably the first clamping device, the wire stretched. The wire is transported further with the roller feed unit so that the The process can be repeated for the next wire section.

In a variant, the first roller feed unit can be in the feed direction of the Wire can be arranged after the first clamping device, the Roller feed unit comes to lie within the straightening path. Only that can go on second clamping device can be moved. Furthermore, both the first and the second, Clamping devices are designed to be movable.

The length of the straightening section can preferably be adjusted. For example the roller straightener, the first roller feed unit and the first clamping device one unit of the device and the second clamping device as one further unit of the device which is displaceable to the first unit. For example, with a worm drive, the second unit of one The predetermined maximum length of the straightening section is shortened to any dimension become. The maximum length of the route is interrelated with the Length of the path of the movable clamping device, which is determined by the degree of stretching results.

To simplify the wire transport in the entire production, you can choose between the Straightening path and the second clamping device a second roller feed unit in front of second clamping device can be arranged, which supports the wire transport. The arrangement of the second can be particularly great when the number of cycles of the device is high Roller feed unit can be an advantage. When arranging two roller feed units they are preferably operated synchronously. In one variant, for example, only one of the roller feed units is actively operated and the other roller feed unit runs passively. The wire can be pre-tensioned with the second roller feed unit being held.

The first clamping device arranged on the input side, which extends by the stretching length is movable, is preferably arranged on a linear hydraulic booster, which can travel freely programmable paths. A wire rod is preferably 3% up to 5% in the device according to the invention. So the required is Stroke or the movable path of the first clamping device a little more than 5% of the length the maximum straightening distance. Instead of the movable clamping device on one hydraulic power booster, another tensioning device can also be provided.

Alternatively, the second clamping device can be on a linear hydraulic Power amplifier can be arranged, the first being arranged on the input side Clamping device is arranged stationary in this variant. Both can continue Clamping devices can be arranged on linear hydraulic boosters. The Clamping devices are preferably used simultaneously in such an arrangement Move away from each other or alternately in opposite directions until the Wire rod was extended by the desired stretching dimension.

A pressure can is preferably arranged as a sensor on the stationary clamping device. With the pressure cell, the tension in the wire is maintained during the entire process of Stretching and in particular the final value for each stretched wire section. The Pressure cell can, for example, on the basis of a spring (spring principle) or on the Working on the basis of a hydraulic pressure (hydraulic principle). The dates of the Pressure cell are stored in one control unit and for the other Production of drawn wire provided. With the measured and stored values is a discontinuous stretching with simultaneous (online) Quality control enables.

The stored final values can be used for a statistical evaluation for the individual stretched wire sections can be used. It can also be a Stress threshold can be defined, which is certainly on the elastic straight line of the Stress-strain diagram of the wire rod is to ensure that the Wire is absolutely straight and that stretching has started.

Furthermore, the device preferably has a cutting unit arranged on the output side, to cut the stretched wire. The stretched wire is preferred with a Cutting device z. B. a scissors arrangement according to the desired length cut to length. As a variant, the stretched wire can also be used with a cutting torch be cut to length.

To receive the cut wires is preferably at the exit of the device according to the invention arranged a receptacle, which fall to the ground the cut wires are prevented and the wires are used for further processing Provides. If the device is connected upstream of a lattice welding machine, serves the recording as a material depot or storage area from which the required wires can be removed from a feed device of the grid welding machine.

The device preferably comprises a control device which measures the stretching length on the Sets the basis of the wire tension measured with the sensor. Is the total length of the wire section to be stretched more than the length of the straightening path, which is determined by the Distance between the first and second clamping device is given in a first Step extends the wire section by the maximum possible stretching length, which in the percentage relationship to the standard distance. Then the wire is around the Missing amount of the desired total length advanced and again by one Amount stretched in the same percentage ratio, which is divided by the amount of Feeds. The stretching length is preferably automatically increased by the control Adjusted the length of the straightening path or feed.

The controller is typically designed as a module and is not fixed in the device built-in. This allows control to be tailored to the needs of the user or adapted to the local conditions.

A system with a lattice welding machine is advantageous according to the invention Device for producing discontinuously stretched wire upstream. Consequently the stretched and cut wire sections are directly on the grid welding machine made available for further processing and can be used by a Wire feeder of the mesh welding machine can be taken over.

For example, two devices according to the invention for producing discontinuously stretched wire of a system with a grid welding machine be upstream. One of the devices according to the invention produces the cross wires and the other device produces the line wires. From the corresponding Interim storage is, for example, with two feeders Grid welding machine removed the required, stretched wires and for further Processing positioned. With such an arrangement, the production times and the production costs significantly reduced because the components of the two devices and the stretching length to the maximum dimensions of the desired cross and Line wires can be matched while ensuring high Quality of the stretched transverse and longitudinal wires.

In the process for the industrial production of discontinuously stretched wire, a Wire section to be machined gripped and stretched with two clamping devices. With a sensor for measuring the wire tension and a displacement sensor Stress-strain dependency added. This is used for further processing stored associated with the wire section. In a first step, a new one Wire stretched in a so-called start-stop operation and the stress-strain dependency for this specific section of wire. Then the further wire sections are stretched at full power Device and there are only the final values of each individual wire section checked. If a measured end value of an stretched wire section lies outside of a predefined tolerance range, the device can be adapted accordingly or the wire section with the values outside the tolerance discarded. Through this online quality control is throughout the production the wire sections ensures production security and compared to the known methods for a discontinuous stretching of wire sections improved as well as reducing the amount of scrap. There will be no inferior quality Wire sections with wire sections corresponding to the standards for structural steel mats welded, which prevents entire steel mats from being thrown away have to. This leads not only to material savings, but also to one significant time savings in the production of steel mesh.

The method has the advantage that it is possible to work with high cycle numbers and that Production security is improved compared to previous processes. Will stretching Regulated by the tractive force, stretching is only possible with a small number of cycles, since the Force changes continuously from the start of stretching to the desired stretching length. Can at the same time the saved values for each rolled wire bundle or also for each wire section can be printed out. This printout can be used as proof of quality for the material from Steel mats serve. If the wires are sold as semi-finished products, the printed list or a copy of it enclosed with the wire bundle as a quality document become. A quality control is created, which meets every ISO standard and allows a reliable statement about the rod production.

In another process for the industrial manufacture of discontinuously stretched Wire becomes the stretching length for a wire section based on statistical Evaluations of the stress-strain dependency are automatically adjusted continuously. The automatic adjustment takes place e.g. B. on the way and / or the force. Does that change Steel quality or if a new wire rod is inserted into the device, the adapts Machine itself. This process can be used to produce wire sections an operating documentation is created, which on the one hand for the Operational data acquisition and on the other hand used for quality assurance can.

In another process for the industrial manufacture of discontinuously stretched Wire becomes the stretching length for a wire section to a voltage threshold related, which defines the completion of a pre-stretch phase. Relative to the stress-strain diagram of the wire rod is a value as a control point on the elastic Just defines which ensures that the wire section is absolutely straight. First the wire is stretched. With the voltage threshold, the end of the "Grading phase" can be determined. A wire rod supplied as a bundle must first be absolutely straight, so that stretching in the required size and quality is performed. As soon as the sensor detects that it is already at a lower value the wire is absolutely straight, can be used for the subsequent wire sections if necessary the voltage threshold can be reduced.

The voltage threshold value is preferably individual for each wire section determined. The sensor detects when the wire is in an absolutely straight line Position and the applied force is used only for stretching and not straightens the wire more.

Typically, the wire becomes automatic in the longitudinal direction in all processes introduced and cut to length automatically after stretching.

From the following detailed description and the entirety of the claims there are further advantageous embodiments and combinations of features of the Invention.

Brief description of the drawings

Fig. 1

ein Spannungs-Dehnungs-Diagramm für einen warmgewalzten und gerippten Draht (WR) im Walz- und gereckten Zustand; und

Fig. 2

eine beispielhafte Anordnung für eine erfindungsgemässe Reckmaschine.

The drawings used to explain the exemplary embodiment show:

Fig. 1

a stress-strain diagram for a hot rolled and corrugated wire (WR) in the rolled and stretched state; and

Fig. 2

an exemplary arrangement for a stretching machine according to the invention.

In principle, the same parts are provided with the same reference symbols in the figures.

Ways of Carrying Out the Invention

FIG. 1 shows a stress-strain diagram for a hot-rolled and ribbed wire (WR) in the rolled and stretched state. The strain ε is plotted on the abscissa axis 2 of the diagram 1 and the stress σ on the ordinate axis 3. Curve 4 shows the characteristic curve of a naturally hard steel - here a wire rod - in the stress-strain diagram. The wire is drawn and reaches its yield point R _e . Up to this point, the steel is in its elastic range and would regain its original length if the traction were removed. From the yield point R _e , the steel begins to flow with another force (the so-called flow plateau). At the end of the flow plateau 5, the tension in the steel increases further from the end of the flow plateau 5 to the maximum tensile strength R _m (also referred to here as point 6). The region 7 from the zero point to the point of the yield point R _e is referred to as elastic elongation. The area 8 from the point of the yield point R _e to the tensile strength R _m (point 6) is referred to as plastic elongation. If a tensile force continues to be exerted on the steel after the tensile strength R _{m has been reached} , the tension σ drops and the steel begins to constrict at its weakest point until it breaks. By stretching the wire is extended into the area of plastic stretch (e.g. up to point 9). The elongation ε of the wire is usually in the range from 3% to 5%. The wire was cold worked by stretching.

As soon as the stretched wire section is relaxed, the wire section shortens minimally, which is represented by point 10. If the stretched wire is loaded again, the steel essentially behaves like a cold-formed wire, on which the ribs and the reduction in diameter due to longitudinal expansion were formed by cold working. In contrast, the stretched WR has better stretching properties than a ribbed KR. As a result of the stretching, the WR has a new yield strength R _er , which is closer to the tensile strength R _m than the given tensile strength R _{m in} terms of the value of the tension σ (by the difference between the yield strength R _e and the yield strength R _er ) than it is for an unstretched wire is. The wire behaves elastically again in region 11 and plastically in region 12. A preferred stretching limit ratio is achieved with stretching, the better stretching properties of the wire rod essentially being retained.

Wire from wire rod bundles in coils is mainly used on the device according to the invention. The wire inserted into the device is not absolutely straight. Therefore, at the beginning of the application of voltage, the characteristic picture as represented by curve 4 does not result. Until the wire is not absolutely straight, there is a discontinuous curve 13. From the point of intersection 14 of curve 13 with the elastic straight line 15 of curve 4, the actual stretching of the wire begins. A voltage threshold value 16 can thus be defined, which is either determined individually for each wire section to be stretched or is determined as a fixed value. As soon as, for example, a pressure cell measures the voltage threshold, there is certainty that the pre-stretching phase is complete and the actual stretching begins. The voltage threshold value 16 is, for example, 200 N / mm ² , which corresponds approximately to one third of the yield strength R _{e of} the wire material. This tension threshold value 16 can also be set higher in the case of strongly curved wire material, the value of the tension threshold value 16 preferably being clearly below the value of the yield strength R _e (<500 N / mm ² ).

With the sensors, all values can be recorded and are available Control available on the one hand for creating a stress-strain dependency, which is saved assigned to the wire section for further processing. On the other hand, the measured values can be used for a continuous automatic adjustment of the Stretching length based on the statistical evaluation of the stress-strain dependency be used. The stored values can also be printed out and used for the Operating and / or quality documentation can be used. You can continue with the stored values, the various phases from the characteristic curve 4 determine mathematically.

An exemplary arrangement for a stretching machine according to the invention is shown in FIG. 2 shown. The stretching machine 21 comprises on the input side (based on the drawing, left) a roller straightener 22 to which a first roller feed unit 23 connects. This is followed by a first clamping device 24, which is based on a hydraulic Linear amplifier 25 is arranged on which the first clamping device 24 horizontally is controlled controlled. These components form a first part 26 of the stretching machine 21. A second part 27 is formed by a second clamping device 28, which a Includes cutting device 29. The second part 27 can also be a second Include roll feed unit. With the second roller feed unit For example, the wire 31 is kept under tension or it serves the Supporting the first roller feed unit 23 when feeding the wire 31.

By dividing the stretching machine 21 into a first part 26 and a second part 27, which can be moved relative to one another with a separate device (not shown here), the length of the straightening section 32 can be varied if necessary. To the two parts To move to each other, for example, the first part 26 can be fixed on a frame mounted and the second part 27 z. B. be fixed on a worm gear, which with an engine is operated. The length of the straightening section 32 can thus meet the requirements be adapted to production. The straightening section 32 is, for example, by a stable steel girder (e.g. a U-profile, such as a UNP or UAP) is formed. So that Straightening section 32 can be adjusted in length, for example, two nested U-profiles arranged, which according to the set Overlap length. In a variant, the second part 27 can have a recess be provided or be constructed in such a way that the steel girder of the straightening section 32 does so penetrates when the length of the straightening section 32 by moving the second part 27 is shortened.

The straightening section 32 begins at the first clamping device 24 and ends at the second clamping device 28. The maximum straightening distance 32 can correspond to the Desires or requirements of the user, the maximum stroke of the hydraulic linear amplifier 25 is to be considered. For example, if the length the straightening distance is 4,000 mm and the usual degree of stretching is from 3% to 5% the stroke of the movable first clamping device 24 must be at least Amount to 200 mm. If the straightening section 32 z. B. enlarged to 8,000 mm, would have consequently the stroke of the movable first clamping device 24 corresponds to the The length of the straightening section 32 must be at least 400 mm. With the nowadays Available resources are for constructive reasons and with regard to the Production costs and due to the serviceability of the stretching machine 21 It makes sense to limit the length of the straightening section 32 to less than 5,000 mm.

For example, on a stretching machine 21 with a maximum straightening distance 32 of 4'000 mm a wire section z. B. will be produced with a length of 6,000 mm proceed as follows: The wire is advanced to a length of 4,000 mm and, at a degree of stretching of 5%, stretched by 200 mm. Then the wire is turned again 2'000 mm pushed and stretched again by 100 mm. Thus, a 6,000 mm long wire section produced, which was stretched by 5%.

The process for producing a discontinuously stretched wire described. The wire rod bundles 33.1 and 33.2 are on a double, horizontal drain 34 for processing in the stretching machine 21 provided. With the use of a double, horizontal drain 34 can for example the end of the wire rod bundle 33.1 with the beginning of the Wire rod bundle 33.2 are welded so that work can be carried out without interruption can. After the entire wire rod bundle 33.1 has been processed, a new one Positioned wire rod bundle on the drain and its start if necessary to the End of the wire rod bundle 33.2 welded. Thus, continuously and without Interruption wire sections are produced in large quantities.

The beginning of the wire rod bundle 33.1, for example, is in the stretching machine 21 introduced or shot and prepared in the roller straightener 22 such that the Pushing the wire 31 is facilitated. The wire 31 is subsequently from the First roller feed unit 23 is detected, which connects to the roller straightener 22. The first roller feed unit 23 consists of two oppositely directed rollers 35.1 and 35.2, between which the wire 31 is advanced, and two drives 36.1 and 36.2, which drive the rollers 35.1 and 35.2 in a controlled manner and preferably are coordinated. Instead of two separate drives 36.1 and 36.2 only one drive both roles 35.1 and 35.2 z. B. drive via a gear. In order to different wire diameters without any special effort in a stretching machine 21 can be processed, are at least the lower or upper roles of the Roller straightener 22 and the first roller feed unit 23 in one direction slidably mounted, e.g. B. in vertical. The zero position of the rollers corresponds to that smallest wire diameter to be processed (e.g. 4 mm) and the minimum Movement of the movable rolls must be the largest to be processed Correspond to wire diameter (e.g. 12 mm). The setting of the gap between the rollers can passively due to the diameter of the inserted Wire 31 or actively mechanically controlled. In a variant, the Rolling surfaces of the rollers can be coated with a deformable material, which the Machining of the entire diameter range (e.g. 4 mm to 12 mm) enables without that the rollers have to move in one direction.

The wire 31 is fed to the second clamping device 28 with the roller feed unit 23 advanced. The first clamp 24 and the second clamp 28 are constructed essentially the same. They have at least two jaws 37.1 and 37.2 or 38.1 and 38.2, which are movable relative to each other and the clamp wire 31 in between. The jaws 37.1 and 37.2 and 38.1 and 38.2 are controlled mechanically or hydraulically.

The first clamping device 24 is arranged on a hydraulic linear amplifier 25, which can travel freely programmable paths. In this exemplary embodiment, the stretching force generated by the linear amplifier 25 is approximately 70 kN and enables a wire with a diameter of 12 mm to be stretched up to its maximum yield point of approximately 630 N / mm ² . The wire 31 to be stretched is held by the first clamping device 24 and the second clamping device 28. The first clamping device is then moved in the clamped state by the desired degree of stretching against the direction of insertion. The front pair of rollers 35.1 and 35.2 must rotate against the direction of insertion of the wire 31 so that the stretching path is compensated for. The first stretched wire section is produced in a start-stop function (stop-and-go). As soon as the values for this wire rod bundle have been recorded and saved, the stretched wires are produced. If differences in the measured end values during production that are outside the defined tolerance range are determined, the force or degree of stretching is adjusted. At the same time, stretched wires that do not meet the desired requirements or have material defects can be sorted out and removed from the further manufacturing process, for example in the manufacture of structural steel mats.

In the next step, the stretched wire with the first roll feed unit 23 transported on. If two roll feed units in one stretching machine arranged, they are preferably coordinated (i.e. synchronously), or actively or passively depending on the position of the wire 31.

A cutting device 29 is arranged on the second clamping device 28 the stretched wire 31, for example with a scissor device to the desired Measure to length.

In another process for the industrial manufacture of discontinuously stretched Wire becomes the stretching length for a wire section based on statistical Evaluations of the stress-strain dependency are automatically adjusted continuously. The statistical evaluation is based on an average, which is based on a predefined number, e.g. B of fifty wire sections, measured and stored values is created. The automatic adjustment of the stretching length can doing z. B. on the way and / or force. Does the steel quality change or if a new wire rod is inserted into the device, the machine adapts itself. This process can be used to produce wire sections Operating documentation are created, which for example for the Operating data acquisition or for quality assurance can be used.

In another method for the industrial production of discontinuously stretched wire, the stretching length for a wire section is related to a stress threshold value, which defines the completion of a pre-stretching phase. In relation to the stress-strain diagram of the wire rod, a value is defined as a control point on the elastic straight line, which ensures that the wire section is absolutely straight. Such a voltage threshold for wire material that is used for the production of structural steel mats and that complies with the relevant standards is in the range of 200 N / mm ² and 500 N / mm ² . First the wire is stretched. When the voltage threshold is reached, the end of the "grading phase" is determined. A wire rod supplied as a bundle must first be aligned absolutely straight so that the stretching is carried out in the required size and quality. As soon as the sensor detects that the wire is absolutely straight even at a lower value, the voltage threshold value can be reduced for the subsequent wire sections. This has the advantage that the number of cycles of the device and thus the amount of drawn wire increased. If the voltage threshold is reached, stretching of the wire section can begin until the desired final value is reached.

The number of cycles of the device according to the invention is based on the cycle time Production of a wire section, which results from the advance of the wire section, the clamping of both clamping devices, the stretching stroke and the opening of the clamps and the sum of the split times. By the inventive Processes allow discontinuous stretching, for example for a Wire section length of 2,000 mm, a cycle rate of 110 pieces / min (= 3.66 m / s) enable.

To change the diameter, the wire 31 is withdrawn completely and the new one Wire is inserted or shot into the stretching machine 21. Through the The adjustable components of the individual devices described can be set to manual Adjustments to the individual devices of the stretching machine can be dispensed with, which the Productivity of the stretching machine significantly increased compared to the prior art. The Diameter changes can be automated with simple means.

Another way to increase productivity is to arrange two units, which are connected in parallel. The two units can use only one Hydraulic unit are operated.

The stretching machine 21 can be used as a stand-alone solution or as an integration in one Plant for the production of structural steel mats are used, the stretching machine the actual system is preferably connected upstream. That is, that in the Stretching machine stretched wires directly to the plant for the production of steel mesh Made available and taken over by them for further processing.

In summary, it should be noted that an apparatus and associated method were created, which combines the stretching and straightening process and one discontinuous stretching in an industrially acceptable number of cycles with simultaneous Quality control enables.

Claims (16)

Device for the industrial production of discontinuously stretched wire (31) with two spaced-apart clamping devices (24 and 28), of which at least one (24) can be moved by a stretching length, characterized in that at least one of the mentioned clamping devices (24 or 28) with a Sensor for determining the wire tension is equipped. Apparatus according to claim 1, characterized in that means are provided for inserting or advancing the wire in the longitudinal direction of the wire. Apparatus according to claim 1 or 2, characterized in that it is provided on the input side with a roller straightener (22). Apparatus according to claim 3, characterized in that a first roller feed unit (23), a first clamping device (24), a straightening path (32) and a second clamping device (28) are arranged in the feed direction of the wire after the roller straightening unit (22). Apparatus according to claim 4, characterized in that a second roller feed unit is arranged between the straightening section (32) and the second clamping device (28). Apparatus according to claim 4 or 5, characterized in that the first clamping device (24) is arranged on a linear hydraulic booster (25). Device according to one of claims 1 to 6, characterized in that a pressure cell on the stationary clamping device (28) is arranged as a sensor. Device according to one of claims 1 to 7, characterized in that it has a cutting unit (29) on the output side for cutting the stretched wire (31) to length. Device according to claim 8, characterized in that it has a receptacle on the output side for the intermediate storage of the cut, stretched wire (31). Device according to one of claims 1 to 9, characterized in that it comprises a control device which adjusts the stretching length on the basis of a measured wire tension. System with a grid welding machine and an upstream device (21) for producing discontinuously stretched wire (31) with two spaced-apart clamping devices (24 and 28), at least one of which (24) can be moved by a stretching length, characterized in that at least one of them also a sensor for determining the wire tension. Method for the industrial production of discontinuously stretched wire, wherein a wire section (31) to be processed is detected and stretched with two clamping devices (24 and 28), characterized in that a voltage-strain dependency is recorded with a sensor for measuring the wire tension and a displacement sensor and that it is stored assigned to the wire section for further processing. Method for the industrial production of discontinuously stretched wire, wherein a wire section (31) to be processed is detected and stretched with two clamping devices (24 and 28), characterized in that a voltage-strain dependency is recorded with a sensor for measuring the wire tension and a displacement sensor and that the stretching length is continuously and automatically adjusted on the basis of statistical evaluations of the stress-strain dependency. Method for the industrial production of discontinuously stretched wire, wherein a wire section (31) to be processed is detected and stretched with two clamping devices (24 and 28), characterized in that a voltage-strain dependency is recorded with a sensor for measuring the wire tension and a displacement sensor and that the stretch length is related to a tension threshold that defines the completion of a pre-stretch phase. A method according to claim 14, characterized in that the voltage threshold value is determined individually for each wire section (31). Method according to one of claims 12 to 15, characterized in that the wire (31) is automatically introduced in the longitudinal direction of the wire and is automatically cut to length after stretching.

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