EP4263084A1

EP4263084A1 - Method and apparatus for straightening elongated elements

Info

Publication number: EP4263084A1
Application number: EP21847782.6A
Authority: EP
Inventors: Massimo Montemarani; Marco Cesari
Original assignee: Schnell SpA
Current assignee: Schnell SpA
Priority date: 2020-12-21
Filing date: 2021-12-15
Publication date: 2023-10-25
Also published as: WO2022137270A1

Abstract

The method for straightening elongated elements, in particular metal elements, provides for arranging along a feeding line, for at least one element (2) in a feeding direction (A), a drawing assembly (3, 3') and a straightening assembly (4, 4') comprising at least a first unit (40, 40') configured to subject the element (2) to a yielding action; then, it provides for feeding the element (2) along the feeding line by means of said drawing assembly (3, 3') through said straightening assembly (4, 4'), for detecting by means of a measuring assembly (5) a datum relating to the quantity of energy expended for said yielding action, made upon the element (2) by said straightening assembly (4, 4') or, in particular, by said first unit (40, 40') of the straightening assembly and for sending said datum indicative of said amount of energy expended to a processing unit.

Description

METHOD AND APPARATUS FOR STRAIGHTENING ELONGATED ELEMENTS Technical field

[01] The present invention relates to a method and an apparatus for straightening elongated elements, in particular metal elements, metal sections and rods for reinforced concrete and similar products.

Prior art

[02] Apparatuses for processing profiles, in particular metal profiles, are known, which provide straightening assemblies, intended to straighten the material before use or before subsequent cutting to size and possibly bending and calendering processes. Straightening is necessary to eliminate any deformations shown by the material, especially if it is packaged in rolls and therefore is also deformed by the same winding condition.

[03] Various types of straightening assemblies are known, for example with rollers, rotors, hyperbolic rotors. In any case, these groups provide for guiding the element through a path with alternating curvature loops, aimed at imparting a yielding action that serves to "cancel" the deformations present in the material, straightening it and at the same time making it more ductile in order to permanently leave the element in the desired configuration, preferably straight or with the desired geometry, following processing subsequent to straightening. In other words, the yielding action serves to allow a "stable" deformation as the element unfolds, which, for technological reasons, does not have the same characteristics over the entire length.

[04] For example, the aforementioned apparatuses may comprise straightening assemblies made by means of a plurality of pairs of counter-rotating wheels or rollers, staggered along the feeding line, through which the element is fed, so as to subject each section of the element in transit to cyclical yielding actions due to bending, aimed at eliminating the original curvature.

[05] Patent US 1 ,239,175 illustrates, for example, an apparatus for straightening metal wires, comprising a first set of counter-rotating wheels and a second set of counter-rotating wheels, arranged on mutually orthogonal planes.

[06] In any case, the straightening units require adjustment actions, to adapt the sinuosity of the path, and therefore the straightening actions, to more or less deformed type and state of the material to be treated.

[07] Only in recent times this adjustment has been at least partially automated, since, until recently, it was performed manually by the operator who, on the basis of visual detection and his own experience, changed the set-up of the various straightening members, up to achieving, through subsequent attempts, a result deemed acceptable. More precisely, the operator observed each produced piece, visually checking the presence of any residual

2 curvature. In this case, he identified its orientation, for example based on the imprint left on the material by the cutting means. In particular, the operator visually estimated the Cartesian components of this residual curvature and intervened in a corresponding manner on the involved straightening means.

[08] Various solutions have been proposed by the Applicant to facilitate and automate this step. For example, the patent EP3445509 illustrates a method and an apparatus for automatically adjusting the straightening of metal elongated elements. In particular, the patent illustrates a detection assembly comprising at least a first sensor element positioned on a first detection plane and a second sensor element positioned on a second detection plane, to detect respectively at least one first datum and a second datum, respectively indicating an instant value of the distance from a section of the element being processed. These measurements, suitably processed by a control unit, are used to provide indications of the degree of straightness obtained and, therefore, indications of regulation for the straightening members.

[09] Furthermore, patent EP3209973, of the same Applicant, illustrates a magneto resistive sensor that can be used in detecting the positioning of a section of the element being processed, to automatically provide data indicative of any residual bends to the control unit of a processing apparatus, useful for an automatic adjustment of the straightening members.

[10] More precisely, solutions which, on the basis of measurements on the curvature of the material, collected downstream of the straightening members, act in feedback to adjust the straightening members, are known in the art.

[11] The known solutions, however, do not fully satisfy the needs of the specific sector, since the correction carried out in feedback is not always capable of effectively and stably eliminating the residual deformations present in the material.

Disclosure

[12] The aim of the present invention is to solve the aforementioned problems, devising a method and an apparatus for straightening elongated elements, in particular metal elements, which achieves an effective straightening, in particular stable over time, in an easy way.

[13] A further object of the present invention is to offer a method and an apparatus for straightening elongated elements, in particular metal elements, which straighten these elements in a completely automatic way.

[14] Another object of the present invention is to provide a method and apparatus that allow straightening elongated elements, respecting the requirements imposed by law and regulations in force for metal profiles to be used, in particular, in the construction sector.

[15] Still another object of the present invention is to provide a method and an apparatus that

3 allow to straighten elongated elements with an optimal energy consumption, which avoids waste and excessive stress on the members of the apparatus, thus reducing the consequent wear.

[16] Even further object of the invention is to provide an apparatus for straightening elongated elements, in particular metal elements, having simple construction and functional conception, safe and reliable in use, as well as of relatively low cost.

[17] The aforementioned purposes are achieved, according to the present invention, by the method for straightening elongated elements, in particular metal elements, according to claim 1 , as well as by the straightening apparatus according to claim 11 .

[18] The method for straightening elongated elements, in particular metal elements, according to the invention, provides for arranging, for at least one element along a feeding line in a feeding direction, in any order, at least one drawing assembly and at least one straightening assembly comprising at least a first unit, configured to subject the element to a yielding action. The method then provides for feeding the element along said feeding line by means of the drawing assembly through the at least one straightening assembly, as well as to detect, by means of a measuring assembly, a datum that can be correlated to the quantity of energy expended for said action of yielding, performed in particular by the first unit of the straightening assembly or by the entire straightening assembly.

[19] The aforementioned data, correlated to the aforementioned amount of energy consumption, is then sent to a processing unit, which in turn processes, by correlation, a degree of yield obtained on the element by feeding it through the straightening assembly.

[20] Basically, the method according to the invention is based on a correlation between the amount of energy consumed by the straightening assembly, in particular by the aforementioned first unit, and the degree of yield suffered by the element.

[21] In other words, the method provides for carrying out a direct or indirect detection of the aforementioned energy consumption, by measuring an easily measurable quantity, for example the temperature of the element, the axial stress on at least one member of the straightener, as a constraining reaction produced by the yielding action on the element, the electrical absorption of a drive assembly of the drawing assembly or the activation frequency of a part of the straightening assembly, configured for a precise correction of the degree of straightening. Each of these measurements represents, possibly also separately, a quantitative indicator, proportional to the energy transferred to the element due to the suffered deformation.

[22] The method may also provide for a combination of these direct or indirect detections.

[23] The determination of the degree of yield obtained thanks to the measuring assembly then permits to establish whether it is sufficient for obtaining a stable straightening or, conversely, whether it is excessive, in order to avoid excessively damaging the material

4 constituting the element.

[24] For this purpose, the method provides for comparing the degree of yield thus elaborated with a minimum threshold value, in order to suitably adjust the straightening members of the first unit, if this threshold has not been initially reached.

[25] The method involves comparing the degree of yield processed with a maximum threshold value, in order to avoid excessive yielding of the element, which could cause the deterioration of the mechanical characteristics of the element, as well as an excessive expenditure of processing energy and premature and unnecessary wear of the parts of the apparatus.

[26] Preferably, the method provides that the processing unit makes an appropriate feedback on the straightening unit, in particular on the first unit, further processing an adjustment command based on the degree of yield related to the said indicative datum.

[27] According to the invention, the method can stably erase the "memory" of the shape previously assumed by the element, preferably acting in an adjustment range in which the yield undergone by the element upon passing through the straightening assembly is at least sufficient o the most suitable for obtaining an optimal result in terms of stability and energy consumption or not excessive, that is such as to damage the material by modifying the established mechanical characteristics.

[28] In fact, the material of which the element is made, for example steel, usually has an elasticity that tends to make it return at least in part to its original geometry when this is forcibly deformed.

[29] Usually, if the element is wound in rolls, it has a main curvature given by the roll winding, but also other shape anomalies, for example buckles, oriented in different directions, whose radius of curvature is presumably different and accidental with respect to that of the main curvature.

[30] According to the invention, this "shape memory" is deleted, effectively controlling the degree of yield, therefore the degree of non-elastic deformation, imposed in at least a part of the section of the element by the straightening members, so as to obtain a stable straightening.

[31] The control of the degree of yield, in other words, allows the determination of the portion of the section of the element actually affected by yield or plasticization. If this share is sufficient, with respect to the entire section, then the element can be straightened in a stable way, even if the remaining portion is deformed in an elastic way.

[32] This portion is controlled in an optimal way, according to one aspect of the method, by comparing the degree of yield processed with minimum and maximum threshold values, as previously mentioned, to ensure effective straightening, but also to prevent the yielding action from being excessive and that therefore involving a waste of energy, as well as the

5 useless deterioration of the element and of the mechanical members of the drawing assembly and of the straightening assembly.

[33] Preferably, it is also important to check that the yielding action does not exceed the maximum threshold value, in order to avoid the alteration of the mechanical characteristics of the material and, instead, to guarantee the satisfaction of the requirements imposed on the materials by the regulations in force, for example by the standards called "Eurocodes", applicable to construction materials.

[34] The method preferably provides for feeding the element through at least a second unit of the straightening assembly, arranged downstream of the first unit, to exert a precise correction or straightening action thereon, aimed at cooperating with the first unit so that the element achieves the desired degree of straightness.

[35] This correction action can preferably be exercised with the coordination of a detection assembly arranged downstream of the second correction unit, configured to detect a position datum of the element, indicative of the degree of straightness of the element downstream of the straightening assembly, preferably of the second unit, and possibly allowing the feedback regulation of the second unit.

[36] This detection assembly can be for example of the type in contact with the element to be straightened, for example of the type illustrated in the application W02020/230181 of the same Applicant, or without contact, for example by means of one or more sensors of the type illustrated in the patent EP3445509 or in application W02020/174507 of the same Applicant, or more generally for example magneto resistive, optical, laser or similar sensors.

[37] Preferably, the datum indicative of the aforementioned amount of energy expended is the frequency with which the second unit is activated to perform the correction or precise adjustment.

[38] In this case, the minimum threshold value corresponds to a maximum frequency value, which may indicate an excessive activation of the second unit and therefore an insufficient degree of yield of the element.

[39] The maximum threshold value in this case corresponds to a minimum frequency value, indicative of a reduced activation of the second unit and therefore of an excessive degree of yield of the element.

[40] The method preferably comprises the further steps of detecting the frequency with which the second unit is activated, checking if the detected value is included in an interval between said minimum frequency value and said maximum frequency value and intervening on an adjustment of the first unit if the detected frequency value is out of said range.

[41] Preferably, the method provides that the data indicative of said amount of energy is a

6 temperature variation. In this case, said measurement assembly detects on the element a current temperature value downstream of the first unit of the straightening assembly and, preferably, a temperature reference value upstream of the first unit.

[42] Said temperature variation then results from the difference between the current value and said reference value, or between the current value and the ambient temperature, if it is assumed that the element enters the straightening assembly at this temperature condition.

[43] It is also possible to provide that said current temperature value is detected downstream of the second unit of the straightening assembly, at which the increase in energy consumption may be detected, considering that the contribution of the precise adjustment operations of the straightening that take place through this second unit is reduced.

[44] Essentially, in this case the method provides for indirectly measuring the amount of energy spent for the yielding action on the element.

[45] In other words, in this case, the method involves measuring the effect due to the yielding action, in terms of transformation into heat, of the transfer of mechanical energy to the element. The difference in temperature read between the inlet and outlet of the straightening assembly, in particular of the first unit, permits to effectively trace the amount of energy consumption and therefore the degree of yield imparted to the element.

[46] Alternatively or in addition, the method can provide that the data indicative of the amount of energy is a variation in the absorption of an actuation unit of the drawing assembly. The measuring assembly then detects an absorption value.

[47] Basically, in this case the amount of energy spent on the element for yielding is measured directly.

[48] This method of implementing the method according to an aspect of the invention, in order to measure the amount of energy spent to stretch the element at the yield strength, can be compromised by the undesired inclusion, in the measurement, of the absorption required for unrolling the element and of the inertia of the relative reel set in motion which, moreover, varies with the consumption of the latter. This absorption rate, which normally is discontinuous, due only to drawing, could be further distorted by the effect of braking actions, for example of mechanical origin, which can oppose the regular unrolling of the element. The apparatuses, in general, draw the element discontinuously, due to accelerations and decelerations due to the unrolling action and the arising inertia actions, also as a function of the set working speed.

[49] To overcome these circumstances, it is possible to provide for feeding the unwinding element and for continuously measuring the absorption associated with the drive unit of the drawing assembly. The minimum value detected in a given time interval is then detected. This minimum value presumably corresponds to the circumstance in which the element is not tensioned by the unwinding unit and therefore the absorption measured on

7 the drawing assembly instead depends only on the crossing of the straightening assembly, therefore on the exerted yielding action.

[50] The method according to the invention therefore allows not to excessively wear the apparatus and to control the consumption of electricity by keeping it to the strict minimum needed to obtain the desired result.

[51] The method according to the invention is applicable to any type of straightening assembly, for example with rollers, rotors, hyperbolic rotors, with the appropriate adaptations to individual cases.

[52] The apparatus for straightening elongated elements, in particular metal elements, according to the invention, includes a drawing assembly and a straightening assembly equipped with at least a first unit configured to subject the element to a yielding action. The apparatus also comprises a measurement assembly configured to detect a datum indicative of the amount of energy spent for the aforementioned yielding action, performed in particular by the first unit of the straightening assembly, as well as a processing unit configured to correlate the data indicative of said quantity of energy with a degree of yield obtained on the element by passing through the straightening assembly.

[53] The processing unit is also configured to compare said processed degree of yield with a minimum threshold value and/or with a maximum threshold value, corresponding, respectively, to a degree of yield insufficient for obtaining a desired straightening and to a degree of excessive yielding, which can lead to the deterioration of the element and/or excessive energy consumption.

[54] Preferably, the measuring assembly comprises at least one temperature sensor device, preferably of the non-contact type, for example a laser detector or a thermal imager.

[55] Preferably, the measuring assembly is configured to detect a current temperature value of the element downstream of the first unit of the straightening assembly and, preferably, a temperature reference value of the element upstream of the first unit. The data indicative of the aforementioned amount of energy is then a temperature variation resulting from the difference between the current value and the temperature reference value.

[56] The measuring assembly preferably comprises at least one energy absorption sensor, connected to a drive unit of the drawing assembly.

[57] The measuring assembly is preferably configured to detect a current absorption value and an absorption reference value. Said indicative data of the amount of energy absorbed by the element is then a change in absorption resulting from the difference between the current value and the reference value of absorption.

[58] The measuring assembly preferably comprises at least one sensor for measuring the axial stress, connected to the support of the straightening assembly and configured to detect a datum indicative of the constraint reaction transmitted by the element to the support by

8 virtue of said yielding action, therefore, indicative of said action.

[59] The measuring assembly is preferably configured to detect a current axial stress value. Said indicative data of the amount of energy absorbed by the element as a result of the yielding action is then a measure of said axial stress.

[60] Preferably the apparatus comprises, in this case, at least one sensor device of the type of a strain gauge or a load cell, to detect this axial stress.

[61] The apparatus also preferably comprises a detection assembly arranged downstream of the straightening assembly to detect a position datum, indicative of the residual curvature or degree of straightness of the element, for example according to patent EP3445509 or according to applications W02020/174507 or W02020/230181 of the same Applicant.

[62] The straightening assembly preferably comprises a second unit, arranged downstream of the first unit or in the final part thereof, and configured to perform a precise correction of the straightening carried out on the element. Alternatively, the second unit can be made by an extension of the first unit, in particular by a respective set of wheels, to perform said precise adjustment or correction of the straightening action, with yielding, already performed on the element by the first unit.

[63] The apparatus can include several straightening assemblies, for example arranged on mutually incident planes. In this case it is preferable to detect a degree of yield for each straightening assembly.

[64] The aforementioned measuring assembly may include at least one frequency detector configured to detect the frequency with which the second unit is activated to perform the precise correction or adjustment. In this case said minimum threshold value corresponds to a maximum frequency value and said maximum threshold value corresponds to a minimum frequency value.

[65] The frequency detector can be conformed by the same memory register of the control unit of the apparatus, which records the adjustment actions carried out on the second unit. Alternatively, the frequency detector can be an additional device, intended to detect said activation frequency of the second unit.

[66] The processing unit can be configured to check whether the frequency value detected by said frequency detector is included in an interval between said minimum frequency value and said maximum frequency value and to intervene on an adjustment of the first unit if the detected frequency value is out of this range.

[67] The method and apparatus according to the invention can be applied to the power supply of one or more elements at the same time.

Description of drawings

[68] The details of the invention will become more evident from the detailed description of a preferred embodiment of the apparatus for straightening elongated elements, in particular

9 metal elements, according to the invention, illustrated by way of example in the accompanying drawings, wherein:

Figures 1 and 2 are respectively a perspective view and a front view of the apparatus for straightening elongated elements, according to the invention;

Figures 3 and 4 are respectively a second embodiment of the apparatus according to the invention, in which a further straightening assembly is used.

Description of embodiments of the invention

[69] With reference to Figures 1 and 2, an apparatus for straightening elongated elements 2, in particular rods and metal profiles is indicated as a whole with the reference number 1 .

[70] The apparatus 1 can be used for the processing of only one element 2 at a time or of a plurality of elements 2, for example a pair, fed simultaneously.

[71] The apparatus 1 comprises a drawing assembly 3, a straightening assembly 4 and a measuring assembly 5, preferably in succession along a feeding line according to a feeding direction A.

[72] The drawing assembly 3 comprises a pair of wheels 3a, 3b, which are opposite each other with respect to the feed line and counter-rotating, around rotation axes lying on the same plane orthogonal to the feed direction. The wheels of the drawing assembly 3, as known in the art, are alternatively movable between a rest condition, in which they are moved away from the feed line and do not engage the element 2 to be drawn, and an active condition, in which the wheels are brought close to element 2, to impose a dragging action thereon.

[73] At least one of the driving wheels, for example the wheel 3a from a first side of the feed line or both are rotated by a suitable drive unit, comprising at least one motor member known in the art. This drive unit absorbs a quantity of energy to exercise the drawing action of the element 2 in particular through the straightening assembly 4.

[74] It is possible to provide a detection unit associated with said drive unit, to measure such amount of absorbed energy.

[75] The drawing assembly 3 may comprise one or more assemblies and can be of any type, for example with wheels, tracks, pliers or a combination of these types, provided that it is suitable for the purpose of supplying the element 2, for example by pulling it or pushing it, through the apparatus 1.

[76] The drawing assembly 3 can be arranged in any position of the apparatus, for example upstream, downstream or between straightening assemblies 4, if provided in a plurality, as described below, or be made by at least part of the straightening assembly, by suitably motorizing certain parts thereof.

[77] The straightening assembly 4 comprises a first unit 40 and, preferably, a second straightening unit 41 .

[78] In the embodiment illustrated in Figures 1 and 2, the first unit 40 and the second unit 41

10 are of the roller type, but it is possible to provide that one or both are of a different type, for example of the type with rotors or hyperbolic rotors or even mixed.

[79] The first unit 40 comprises for example a first series of rollers 40a and a second series of rollers 40b, which are opposite and staggered along the feed line.

[80] As is known, the rollers 40a, 40b are alternatively movable between a rest condition, away from the element 2, and a working condition, in which they are mutually moved near to engage the element 2, defining a loop path between them aimed at exerting a yielding and therefore a straightening action on the fed element 2.

[81] More precisely, this yielding action serves to plasticize at least part of each section of element 2, so as to cancel the "memory" of previous deformations or curvatures present on element 2.

[82] The second unit 41 is arranged downstream of the first unit 40 or part thereof, to perform a so-called "fine" correction action of the straightening. It can be of a known type, for example of the type illustrated in EP2600991 or in EP 0947256 of the same Applicant. Alternatively, the second unit 41 can be made by a final part of the first unit 40, or by an extension thereof, in particular by a respective set of wheels, to perform said "fine" adjustment or correction of the straightening action with yield already carried out on element 2 by the first unit 40.

[83] The second unit 41 comprises, for example, a pair of contrast wheels 41a, which are opposite and staggered with respect to a central wheel 41 b. The contrast wheels 41a and the central wheel 40b are movable by an adjustment, reciprocal moving near or away, so as to accentuate or, on the contrary, reduce the corrective action exerted by the second unit 41.

[84] The apparatus 1 also includes a measuring assembly 5, configured to detect a data indicative of the amount of energy absorbed by the element 2 due to the straightening action through the straightening assembly 4. Essentially, this data is indicative of the degree of yield of the element 2, therefore of the effectiveness and stability of the straightening.

[85] Preferably the measuring assembly 5 detects said data, in relation to the straightening action, in particular the yielding action, exerted on the element 2 by the first unit 40.

[86] The measuring assembly 5 may comprise for example a sensor device 50, for example a thermal imager or a laser detector, configured to detect an actual temperature value of the element 2 downstream of the straightening assembly 4, preferably downstream of the first unit 40, between the first unit 40 and the second unit 41 , or, alternatively, downstream of the second unit 41. In the latter case, the present value is also affected by the effect of the finishing action exerted by the second unit 41 , which is very low compared to the yielding action exerted especially by the first unit 40, but which is also representative of a small

11 energy contribution for the straightening.

[87] The measuring assembly 5 preferably comprises a further sensor device 51 configured to detect a reference value of the temperature of the element 2 upstream of the straightening assembly 4.

[88] The indicative data can then be represented by the temperature variation At through the straightening assembly 4 or, in particular, through the first unit 40.

[89] In this case the temperature variation can be given by the difference between the current temperature value measured by the sensor device 50 and the reference value given by the ambient temperature, assuming that the element 2 is introduced at this temperature in the straightening assembly 4.

[90] Alternatively, the temperature variation At can be determined by the difference between the current value measured by the sensor device 50 and the reference value measured by the additional sensor device 51.

[91] The apparatus includes a processing unit configured to process the indicative data of the energy spent for the yielding action on element 2, processing current measured values, for example of temperature.

[92] Alternatively or in addition, the processing unit can process this indicative data based on the axial stress exerted on the straightener by virtue of the yielding action and/or based on the power absorbed thereby.

[93] The axial stress can be measured by means of at least one sensor device connected for example to the support of the straightening assembly, preferably made by means of an extensometer device or a load cell device.

[94] The current and reference value of the absorbed power, in particular, can be measured by means of a respective sensor device connected to the drive unit of the straightening assembly.

[95] The apparatus 1 may further comprise a detection assembly 6, arranged downstream of the straightening assembly 4, in particular downstream of the second unit 41. This detection assembly 6 can comprise for example at least one sensor for detecting the position of a section of the fed element 2, so as to determine the degree of straightness of the element 2 and, in the event of deviations from a desired degree of straightness, allow the straightening members, in particular the second unit 41 to do the appropriate corrections.

[96] The detection assembly may be made, for example, according to what is described in patent EP3445509 o in applications W02020174507 or W02020/230181 of the same Applicant.

[97] Alternatively or in addition to the sensor devices 50, 51 and/or to the axial force sensor and/or to the absorption sensor, the measuring assembly 5 can comprise at least one

12 frequency detector, configured to detect the frequency with which the second unit 41 is activated for precise correction or adjustment. In this case said minimum threshold value corresponds to a maximum frequency value and said maximum threshold value corresponds to a minimum frequency value.

[98] The frequency detector can be conformed by the same memory register of a control unit of the apparatus, which records the adjustment actions carried out on the second unit. Alternatively, the frequency detector can be an additional device, intended to detect said activation frequency of the second unit 41 .

[99] The processing unit can be configured to check whether the frequency value detected by said frequency detector is included in an interval between said minimum frequency value and said maximum frequency value and to intervene on an adjustment of the first unit if the detected frequency value is out of this range.

[100] The method according to the invention, as well as the operation of the apparatus for straightening elongated elements, in particular metal elements, according to the invention, are easily understood from the above description.

[101] The element 2 is fed thanks to the drawing assembly 3 along the feed line in the feed direction A, through the straightening assembly 4 which exerts a yielding action for the straightening of the same element 2.

[102] The measuring assembly 5 detects an actual temperature value at a section of the element 2 downstream of the straightening assembly 4, preferably between the first unit 40 and the second unit 41 , and detects or estimates a reference value upstream of the first unit 40 of the straightening assembly 4.

[103] Alternatively or in addition, the measuring assembly 5 can measure a current value for the axial stress transmitted by the element by reaction, for example on the support of the straightening assembly, or for the power absorbed by the straightening assembly, by means of the appropriate sensor devices described above.

[104] Alternatively or in addition, the measuring assembly 5 can measure an actual frequency value with which the second unit 41 is activated to correct the straightening of the element 2.

[105] The measuring assembly 5 transmits these values to the processing unit of the apparatus that processes the difference, and correlates it to the degree of yield of the element 2 due to the crossing of at least the same first unit 40.

[106] This processed degree of yield is then compared with a minimum threshold value and/or with a maximum threshold value. In the event that the degree of yield processed is not included in the interval between the threshold limit values, the processing unit determines the adjustment to be made to the straightening members of the straightening assembly 4, in particular to the first unit 40, so that, for example, the second unit 41 can stably achieve

13 a desired straightening.

[107] At the same time, the detection assembly 6 can coordinate corrective actions on the straightening assembly 4, in particular on the second unit 41 , by detecting data relating to the position of the element, therefore to its curvature, at the output of the straightening assembly 4.

[108] According to a further embodiment, illustrated in Figures 3 and 4, the apparatus 1' can include in addition to the straightening assembly 4 a further straightening assembly 4' oriented orthogonally to the first one. For example, the straightening assembly 4 can be arranged on a substantially vertical plane, while the further straightening assembly 4' can be arranged on a substantially horizontal plane.

[109] Each straightening assembly 4, 4' preferably comprises a respective first unit 40, 40' and a respective second unit 41 , 41'.

[110] The drawing assembly 3', for example made by two pairs of counter-rotating rollers or in any other way, provided that it is suitable for the purpose, is preferably interposed between the two straightening assemblies 4, 4'.

[111] Upstream of the further straightening unit 4', an insertion device 30' can be further provided with the function of allowing the insertion of element 2.

[112] Figures 3, 4 also illustrate, by way of example, a cutting assembly 7 and a bending assembly 8, arranged in succession downstream of the straightening assemblies 4, 4'.

[113] Downstream of the bending assembly 8, the apparatus 1' may usefully comprise said detection assembly 6' to detect the degree of straightness of the element 2. For example, the detection assembly 6' comprises a plurality of detection sensors 60 arranged at or below the work surface 80 of the bending assembly 8.

[114] According to the invention, the apparatus T is functionally completely similar to the first described embodiment. Therefore, the same reference numerals have been used in the figures to indicate structurally and/or functionally similar assemblies or elements.

[115] In particular, the apparatus T comprises a measuring assembly 5, schematically shown in Figure 3, to measure a datum that can be correlated to the energy spent for the yielding of the element 2, so as to obtain, following a possible necessary adjustment, an effective and stable straightening, but never excessive.

[116] The operation is entirely similar to that described for the first embodiment illustrated in Figures 1 and 2.

[117] The apparatus described by way of example is subject to changes according to different needs.

[118] In the practical embodiment of the invention, the used materials, as well as the shape and the dimensions, may be modified depending on needs.

[119] Should the technical features mentioned in any claim be followed by reference signs, such

14 reference signs were included strictly with the aim of enhancing the understanding of the claims and hence they shall not be deemed restrictive in any manner whatsoever on the scope of each element identified for exemplifying purposes by such reference signs.

15

Claims

Claims A method for straightening elongated elements, in particular metal elements, comprising the steps of: a. arranging along a feed line for at least one said element (2) in a feeding direction (A) a drawing assembly (3, 3') and a straightening assembly (4, 4') comprising at least a first unit (40, 40') configured to subject said element (2) to a yielding action; b. feeding said element (2) along said feed line by means of said drawing assembly (3, 3') through said straightening assembly (4, 4'); c. detecting by means of a measuring assembly (5) a datum relating to the quantity of energy expended for said yielding action, operated by said straightening assembly (4, 4') or, in particular, by said first unit (40, 40'); d. sending said datum indicative of said amount of energy expended to a processing unit; e. processing by means of said processing unit, by correlating said data indicative of said amount of energy, a degree of yield obtained on said element (2) by feeding through said straightening assembly (4, 4'); f. comparing through said processing unit said processed degree of yield with a minimum threshold value and/or with a maximum threshold value, corresponding, respectively, to a degree of yield insufficient to obtain a desired straightening and to an excessive degree of yield, which can lead to the deterioration of the element (2) and/or an excessive energy consumption. The method of claim 1 , wherein said datum indicative of said amount of energy is a temperature variation (At), said measuring assembly (5) detecting at least one current temperature value of said element (2) downstream of said first unit (40) of said straightening assembly (4, 4'). The method of claim 2, wherein said measuring assembly (5) detects a reference value of the temperature of said element (2) upstream of said straightening assembly (4, 4'), said temperature variation resulting from the difference between said actual detected value and said reference value. The method of one or more of the preceding claims, wherein said data indicative of the amount of energy expended for said yielding action performed by said straightening assembly (4, 4') or by said first unit (40, 40') is a measurement of the constraining reaction carried out axially in said feed direction (A) by said element (2) on a respective support of said straightening assembly (4, 4'). The method of one or more of the preceding claims, wherein said indicative data of said amount of expended energy is absorption (AE) of an actuation unit of said drawing assembly (3, 3'), said measuring assembly (5) being associated with said actuation unit and configured to detect the absorption of said drawing assembly (3, 3') attributable to said yielding action on said element (2). The method of one or more of the preceding claims, wherein said processing unit operates an appropriate feedback on said straightening assembly (4, 4'), in particular on said first unit (40, 40'), further processing an adjustment command on the basis of said degree of yield correlated to said indicative datum. The method of any one of the preceding claims, wherein the further step is provided of feeding said element (2) through a second unit (41 , 4T) of said straightening assembly (4, 4'), arranged downstream of said first unit (41 , 4T) either in the final part or as an extension thereof, and configured to perform a correction or fine adjustment of the straightening action of said element (2), with yield, made on said element (2) by said first unit (40, 40'). The method of claim 7, wherein said data indicative of said amount of energy is the frequency with which said second unit (41 , 4T) is activated to make said correction or precise adjustment, said minimum value of threshold corresponding to a maximum frequency value and said maximum threshold value corresponding to a minimum frequency value, said method comprising the further steps of detecting the frequency with which said second unit (41 , 4T) is activated, checking whether the value detected is included in an interval between said minimum frequency value and said maximum frequency value and intervening on an adjustment of said first unit (40, 40') if said detected frequency value is outside said interval. The method of any one of the preceding claims, wherein the further step is provided of detecting through a detection assembly (6, 6') arranged downstream said straightening assembly (4, 4'), a datum of position of at least one section of said fed element (2), indicative of the residual curvature or of the degree of straightness of said element (2). The method of claim 9, wherein the further step is provided of adjusting said second unit (41 , 4T) on the basis of said position datum detected by said detection unit (6, 6'), to correct a respective contribution to the straightening action. An apparatus for straightening elongated elements, in particular metal elements, comprising a drawing assembly (3, 3') and a straightening assembly (4, 4') comprising at least a first unit (40, 40') configured to subject said element (2) to a yielding action, characterized in that comprises a measuring assembly (5) configured to detect a datum indicative of the amount of energy expended for said yielding action, operated by said first unit (40, 40') of said straightening assembly (4, 4'), a processing unit configured to process, by correlation to said data indicative of said amount of energy expended, a degree of yield obtained on said element (2) by means of feeding through said straightening assembly (4, 4') and to compare said processed yield degree with a minimum threshold value and/or with a maximum threshold value, corresponding, respectively, to a degree of yield insufficient to obtain a desired straightening and an excessive degree of yield, which can lead to the deterioration of the element (2) and/or to excessive consumption of energy expended. The apparatus of claim 11 , wherein said measuring assembly (5) comprises at least one temperature sensor device (50). The apparatus of claim 12, wherein said measuring assembly (5) is configured to detect an actual temperature value of said element (2) downstream of said first unit (40, 40') of said straightening assembly (4, 4'), said datum indicative of said amount of energy expended being calculated as a temperature variation (At) resulting from the difference between said current value and a reference value of the temperature of the element (2), measured or estimated upstream of said straightening assembly (4, 4'). The apparatus of claim 13, wherein said reference value is the room temperature. The apparatus of claim 13, wherein said measuring assembly (5) comprises a further sensor device (51) configured to detect said temperature reference value of said element (2) upstream of said straightening assembly (4, 4'). The apparatus of any one of claims 11 - 15, wherein said measuring assembly (5) comprises at least one sensor for absorbing the energy expended by an actuation unit of said drawing assembly (3, 3 '). The apparatus of any one of claims 11 - 16, wherein said measuring assembly (5) comprises a sensor device, for example a strain gauge or a load cell, configured to detect a measurement of the constraint reaction carried out axially to said feed direction (A) by said element (2) on a respective support of said straightening assembly (4, 4'). The apparatus of any one of claims 11 - 17, comprising a detection assembly (6, 6') arranged downstream of said straightening assembly (4, 4') to detect a position datum, indicative of the residual curvature or the degree of straightness of said element (2). The apparatus of any one of claims 11 - 18, wherein said straightening assembly (4) comprises a second unit (41 , 4T) configured to perform a precise correction or adjustment of the straightening action, with yield, carried out on said element (2) by said first unit (40, 40'). The apparatus of claim 19, wherein said second unit (41 , 4T) is made downstream either by a final part or by an extension of said first unit (40, 40'). The apparatus of claim 19 or 20, wherein said measuring assembly (5) comprises at least one frequency detector configured to detect the frequency with which said second unit (41 , 4T) is activated to make said precise correction or adjustment, said minimum threshold value corresponding to a maximum frequency value and said maximum threshold value corresponding to a minimum frequency value, said processing unit being

18 configured to check whether the frequency value detected by said frequency detector is included in a interval between said minimum frequency value and said maximum frequency value and to intervene on an adjustment of said first unit (40, 40') if said detected frequency value is outside said interval.

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