Patent Publication Number: US-2022234093-A1

Title: Straightening device for aligning a line, method for braking at least one rotatable roller in a straightening device, cable processing machine with a straightening device, and upgrade kit for a cable processing machine

Description:
This application is a National Stage completion of PCT/IB2021/054722 filed May 19, 2020, which claims priority from European patent application serial no. 19175428.2 filed May 20, 2019. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a straightening device for aligning a line, a method for braking at least one rotatable roller in a straightening device, a cable processing machine with a straightening device, and an upgrade kit for a cable processing machine. 
     BACKGROUND OF THE INVENTION 
     As the number of electronic assemblies in industry grows, so the requirements regarding the quality of the cable sets and cable connections between the assemblies also become more stringent. This in turn means that it is becoming all the more important when processing lines and cables to monitor the line or cable constantly, from the drawing process, through the cutting to length and further processing at the processing stations of the cable processing machines, and avoid damaging the lines. 
     The increasing number of lines needed also means that cable processing machines must work faster and faster. The output quantity of the cable processing machines is a significant economic factor, and besides quality it is a decisive consideration in the customers&#39; purchasing decision. 
     Fully automatic work machines for cable processing must be able to perform processing operations such as cutting to length, insulation stripping, crimping, twisting and tin-plating, as rapidly as possible. Further processing steps, such as welding of lines and automatic winding of the processed lines are available as options. For this purpose, continuous lines are typically drawn from a container, a cable reel or cable drum for example, into the cable processing machine, and aligned by a straightening stand. In this process, the straightening process relaxes the line, minimises its intrinsic torsion and enables axially aligned further process thereof. 
     EP 2 399 856 A1 discloses a straightening stand for aligning lines which has an upper and a lower row of rollers. Both of these rows of rollers can be moved relative to each other, and in this process the delivery route of the line between passes through the two rows of rollers. The rows of rollers include a plurality of rollers which rotate in order to align the line. 
     JP S62 248 528 A discloses an apparatus for straightening rolled, cold-drawn and annealed steel wire, in order to minimise the torsional stress in the wire and subsequently produce coil springs. The apparatus comprises two straightening stands, each having two rows of straightening rollers, wherein the straightening stands straighten the wire mechanically in two planes two planes. 
     The drawback of the known apparatuses is that during the final stopping operation the line to be aligned is only braked by friction of the rollers and walking forces in the line or wire. 
     EP 3 290 370 A1 discloses a wire running apparatus for feeding a wire into a feed device. The wire apparatus comprises a braking apparatus with a brake roller and with a pressure roller as the contact pressure element. The brake roller and the pressure roller are arranged opposite one another and are movable relative to each other. Pressure is applied to the wire between the brake roller and the pressure roller, and the wire is braked thereby as necessary. 
     The drawback associated with this known apparatus is that the wire is braked mechanically, which gives rise to a substantial amount of friction-based heat, and consequently the wire is deformed during braking. 
     U.S. Pat. No. 3,881,578 A discloses a magnet-assisted braking device for rail vehicles, with brake blocks for decelerating the rotary motion of the running wheels on the rail vehicle. A magnetic coil to which an electrical voltage can be applied is arranged on a ferromagnetic connecting member between the running wheels, and with the ferromagnetic brake blocks forms a closed magnetic circuit through the running wheels and stationary rails, wherein an additional attractive braking friction force of the brake blocks on the running wheels is generated by means of the magnetic flux. 
     The drawback of this known solution is that the magnet-assisted braking apparatus gives rise to a substantial amount of frictional heat in the running wheels and said braking apparatus is consequently not suitable for a cable processing apparatus. 
     A braking apparatus of similar species to the solution described above for a rail vehicle is disclosed in CN 102 556 102 A, although this disclosure does not describe direct braking of the rail vehicle&#39;s running wheels and is unsuitable as a braking apparatus for a cable processing apparatus. 
     DE 10 2013 002 020 A1 discloses a winding apparatus for winding a strand-like material to be wound having a winding drum and a movable laying arm. An eddy current brake is mounted on the laying arm as a brake for the material to be wound, and transmits a braking force directed away from the winding drum to the material to be wound as necessary. With the generation of the braking force on the material to be wound, the material to be wound is placed under pretension by tensile force downwards in the direction of delivery to the brake for the material to be wound. 
     The drawback of this known apparatus is that the braking force of the brake for the material to be wound acts directly on the material, with the result that a tensile force is applied to the material that is to wound, and consequently the material is unavoidably deformed. 
     SUMMARY OF THE INVENTION 
     It is the object of the present invention to remedy one or more drawbacks of the related art. In particular, it is intended to create a straightening device in which damage to the line to be aligned due to the effects of friction during braking of said line to be aligned is prevented, as well as a method for braking at least one rotatable roller in a row of rollers of a straightening device, which brings about gentle braking of the line to be aligned. Moreover, a cable processing machine equipped with the straightening device is to be created, in which machine the quality requirements applicable to the line to be aligned can be maintained and an interruption of the processing operation because a line was damaged during the alignment can be avoided, and an upgrade kit for a cable processing machine may be created, with which a cable processing machine can be upgraded. 
     This object is solved with the apparatuses and methods defined in the independent claims. Advantageous further developments are presented in the figures, the description and in particular in the dependent claims. 
     A straightening device according to the invention for aligning a line along a delivery route comprises a straightening stand with a first row of rollers and with a second row of rollers, which are movable relative to each other, and between which the delivery route of the line extends, wherein at least one of the two rows of rollers has a plurality of rotatable rollers, and wherein a braking apparatus is provided for braking at least one of the rotatable rollers of at least one of the two rows of rollers in the straightening stand n des straightening stand. 
     In this context, the braking apparatus is designed to exert a braking effect on the roller of at least one of the two rows of rollers which rotates while the line is being aligned, thereby enabling an effective deceleration of said roller without mechanically overloading or deforming the line that is to be aligned. The line to be aligned is drawn through the straightening stand by means of a line drawing device. Because of the high speeds at which the line is drawn into the straightening stand during alignment of the line and the resulting high rotational energy of the rotating rollers in the rows of rollers, stopping the extremely rapidly moving line drawing device typically causes a loop to form in the line between the straightening stand and the line drawing device. This loop formation stems from the mass inertia of the rotating rollers in the rows of rollers in the straightening device and is caused by the subsequent line lengths coming from the container. The loop in the line may subsequently lead to the line becoming caught on components in the cable processing machine, with the result that production has to be stopped. The repeated restarting of the alignment process with the straightening device in which the previously formed line loop is smoothed flat by the line drawing device, inevitably to a jerky acceleration of the line through the line drawing device, which in turn causes length errors in the line to be aligned. The direct braking of the rollers rotating in at least one of the two rows of rollers with the braking apparatus prevents the abovementioned loop formation between the straightening device and the line drawing device, and the disadvantages described previously may be avoided. In particular, production does not have to be interrupted, and a length error in der line resulting therefrom is prevented. 
     Prevention of loop formation and prevention of the damage that the line may possibly suffer as a result thereof is advantageous particularly in the case of electrical or optical lines, as they are particularly vulnerable to effects such as those described previously, and the quality of the aligned lines is impaired significantly thereby. 
     In particular, the braking apparatus is designed for braking multiple rotatable rollers of at least one of the two rows of rollers in the straightening stand, so that efficiency in the braking operation may be enhanced further, and in turn the line to be aligned is treated yet more gently. The two rows of rollers are arranged on the straightening device so that they can move relative to each other. 
     In an activated state, at least a portion of the braking apparatus is preferably in a contactless operative connection for braking with at least one of the rotatable rollers in at least one of the two rows of rollers. In the activated state, the braking apparatus exerts a braking effect on the at least one rotatable roller in at least one of the two rows of rollers, with the result that its rotating speed is reduced. During this process, the braking apparatus does not touch this roller, so no heat is generated in said braked roller due to mechanical friction effects. 
     In particular, in an activated state the braking apparatus is in a contactless operative connection for braking with multiple rotatable rollers without generating frictional heat at said multiple rotatable rollers in at least one of the two rows of rollers. With the braking apparatus such as described herein, frictional heat which would otherwise be transmitted to the line to be aligned, and which would for example cause a deformation of the power insulation and thus damage its line insulation layer, is prevented. 
     More preferably, the contactless operative braking connection is adjustable. In this way, the braking speed and thus also the deceleration that acts on the at least one rotatable roller, may be adapted to variable properties of the line to be aligned, such as the line diameter, the line type or the thickness of the line insulation layer. Furthermore, it is then possible to adapt a desired braking effect to the drawing speed of the line in the straightening device, thereby further reducing the harsh effects on the line during braking. 
     In particular, the at least one rotatable roller comprises an inner ring and an outer ring, wherein a rolling element unit, for example a ball race or the like, is arranged between the inner ring and the outer ring. The inner ring serves to attach the ball bearing and the outer ring arranged rotatably thereon securely to a stationary arbor of the first or second row of rollers in the straightening stand, wherein the inner ring is arranged statically on said stationary arbor. The rotatable outer ring is arranged rotatably on this arbor by means of the rolling element unit and is able to rotate according to the line drawing speed. 
     Alternatively, the at least one rotatable roller is arranged on the straightening stand on a rotatably mounted arbor and is attached fixedly to this rotatable arbor. The rotatable arbor together with the roller mounted thereon rotates about an axis of rotation, wherein said axis of rotation extends along the longitudinal extension of the rotatable arbor. This provides a simple way to mount the at least one rotatable roller rotatably on the first row of rollers or on the second row of rollers. 
     In particular, the contactless operative braking connection acts on the rotatable outer ring of at least one of the rotatable rollers. Consequently, the deceleration during braking acts on that region of the rotatable roller which has a larger radius and accordingly on a region with high torque, thereby further increasing the effectiveness of the contactless operative braking connection. 
     The rotatable outer ring of the at least one rotatable roller advantageously has a groove for guiding the line that is to be aligned. This serves to prevent the line to be aligned from departing from the straightening stand, which is undesirable. 
     In particular, the contactless operative braking connection acts on the rotatable outer ring of at least one more, in particular of each of the multiple rotatable rollers of the rows of rollers, thereby further improving the braking effect. 
     The braking apparatus is preferably a magnetic braking apparatus, wherein the magnetic braking apparatus comprises at least one permanent magnet or at least one electromagnet. Using magnets such as permanent magnets or electromagnets, it is possible to implement simple and efficient control and adjustment of the effect of braking on the at least one rotating roller. 
     The permanent magnets are advantageously cylindrical or disc-shaped, which enables them to be arranged in the braking apparatus easily and in keeping with the specific application. Further alternative embodiments as examples of the shape of the permanent magnets in the braking apparatus would be a square, annular, round or segmental shape. 
     In particular, the magnetic braking apparatus is an eddy current brake. The eddy currents induced in the at least one rotating roller by the eddy current brake are generated by the magnetic field lines, wherein a force system is created that brakes the one rotating roller or the rotating outer ring of that roller. The heat generated thereby in the one rotating roller or the rotating outer ring of that roller and the heat transmitted therefrom to the line to be aligned is negligible compared to the heating of the line that is to be aligned with mechanical braking of the line to be aligned. 
     Alternative, the magnetic braking apparatus is a hysteresis brake comprising at least two permanent magnets and a positioning unit for moving the at least two permanent magnets. The at least one rotatable roller such as described herein is embodied as a hysteresis disc or hysteresis ring made from a magnetic material, for example from a ferromagnetic material, the hysteresis brake. The at least two permanent magnets create a force line flux within the at least one rotatable roller. The following principle of operation applies: Opposite magnetic poles produce the lowest torque. However, the most powerful hysteresis takes place, and the torque is greatest if the south and north poles of the magnets are arranged alternatingly around the circumference of the hysteresis disc. By varying the angle of the magnetic pole superposition, the torque can be adjusted steplessly, and since there are no touching surfaces the setting is retained indefinitely. At the same time, the torque applied to the at least one rotatable roller is unaffected by the rotating speed of said roller and is this distributed evenly from standstill to maximum rotating speed. 
     The rotatable outer ring of the roller is advantageously made from an electrically conductive material, for example steel, copper, aluminium or the like. In this context, it is possible to generate the braking effect in the form of eddy currents with the magnetic field lines of the permanent magnet in the rotating outer ring of the at least one rotatable roller, as long as the rotatable outer ring is rotating. The eddy currents generated in the rotating outer ring of the at least one rotatable roller are strongest at high rotating speeds, and become constantly weaker as the rotating speed is reduced. The eddy currents in the rotatable outer ring of the at least one rotatable roller brake the rotation of the outer ring contactlessly and extremely effectively. When the outer ring is not rotating, no eddy currents are generated. 
     Also advantageously, the braking apparatus includes a magnet holder for accommodating at least one permanent magnet. The magnet holder enables simple placement of the permanent magnets on the braking apparatus. The at least one permanent magnet may be arranged detachably on the magnet holder so that it is separable from the magnet holder and the permanent magnet can be replaced without tools. 
     In particular, the braking apparatus includes a magnet holder for accommodating multiple permanent magnets, so that multiple permanent magnets can be involved in the operative braking connection, thereby improving the braking effect produced by the multiple permanent magnets on the at least one rotatable roller in at least one of the two rows of rollers. 
     More preferably, the braking apparatus is located at a distance from the at least one rotatable roller. In this context, the braking apparatus arranged with a horizontal and/or vertical separation from the at least one rotatable roller, with the result that the contactless braking apparatus has a simple, compact construction. The distance between the braking apparatus and the at least one rotatable roller allows service maintenance of the braking apparatus to be carried out without difficulty, since the components of the braking apparatus are easily accessible for a user. 
     The braking apparatus preferably comprises a positioning apparatus for at least partially moving the braking apparatus from a first position, in which the braking apparatus is in an inactive state, at least into a second position, in which the braking apparatus is in an activated state. In the inactive state, no braking effect at all acts on the least one rotatable roller in the row of rollers, and therefore the alignment of the line can be carried out largely without resistance. Using the positioning apparatus, the braking apparatus can be activated directly, since the distance from the braking apparatus to the at least one rotatable roller will become smaller, so that the braking effect is produced at least on this one rotatable roller in the row of rollers. 
     In particular, the positioning apparatus is designed as a lifting device, said lifting device being brought towards the at least one rotatable roller vertically, substantially normally to the axis of rotation of the rotatable roller. This allows a simple construction of the positioning apparatus. 
     Alternatively, the positioning apparatus is designed to shift the braking apparatus horizontally, substantially along the axis of rotation of the rotatable roller, so that the positioning apparatus can be arranged with low space requirement in the region of one of the rows of straightening rollers. 
     The magnet holder may advantageously be shifted from a first position, in which the magnet holder and the magnet is in an inactive state, into at least one second position, in which the magnet holder and the magnet is in an activated state. Thus at least one component of the braking apparatus, which is to say the magnet holder, is mounted movably on the braking apparatus. Accordingly, the number of movable components can be reduced, and consequently the construction of the braking apparatus can be designed more simply and less expensively. 
     The positioning apparatus is advantageously embodied as an electric crank mechanism. With the aid of an electric crank mechanism, the braking apparatus and the magnet holder can be moved from a first position to another position quickly and continuously or constantly. 
     More preferably, the positioning apparatus has a housing, by which the movable components of the positioning apparatus are covered, conferring a high level of safety. It may also serve to prevent a line loop from being formed on the positioning apparatus and/or a line loop from being formed inside the straightening stand of the straightening device. 
     In particular, the housing includes a guide section, which enables the braking apparatus to be arranged precisely and reproducibly on the straightening stand. The positioning apparatus preferably includes a drive device, which shifts at least the magnet holder pneumatically, hydraulically or electrically relative to the at least one rotatable roller. With this drive device, the magnet holder can be shifted relative to the rotatable rollers in controlled manner, wherein it advantageously adjusts the distance between the magnet holder and the at least one rotatable roller steplessly. 
     The positioning apparatus advantageously comprises an end plate which has at least one elastic element, such as for example a pretensioning spring. With the aid of the elastic element, it is possible to arrange at least the magnet holder on the braking apparatus such that it can be biased to prevent tilting of the magnet holder while the braking apparatus and the magnet holder is being transferred from the inactive state of the magnets to the activated state of the magnets. 
     More preferably, the magnet holder includes at least two permanent magnets, on each of which the magnetic south poles face substantially in the same direction. Accordingly, the existing magnetic fields of the permanent magnets have the same field line patterns, thus strengthening the operative braking connection between the at least one rotatable roller and the braking apparatus. 
     Preferably, at least one permanent magnet in the magnet holder is a neodymium magnet. Neodymium magnets have a particularly high field strength and are stable, so the braking apparatus needs hardly any maintenance service work. 
     The method according to the invention for braking at least one rotatable roller in at least one row of rollers of a straightening device such as described herein comprises at least the following steps:
         aligning at least one line, wherein the at least one line is drawn through the straightening device, and   braking at least one of the rotatable rollers in at least one row of rollers in the straightening device with a braking apparatus.       

     The method enables effective braking of said rotatable roller in one of the rows of rollers without mechanically loading or deforming the line that is to be aligned. As was disclosed earlier, this in turn prevent loop formation in the line. 
     The line to be aligned is advantageously unwound from a container and drawn into the straightening device. In this context, as described herein a container is understood to be a cable reel, a winding material, a cable drum or similar, in which for example a continuous line is disposed, whereby many line lengths of a continuous line can be aligned in a short time. 
     More preferably, at least a section of the braking apparatus is shifted from a first position, in which the braking apparatus is in an inactive state, at least into a second position, in which the braking apparatus is in an activated state before the previously described braking of the at least one rotatable roller of at least one row of rollers in the straightening device. In the inactive state of the braking apparatus no operative braking connection acts on the at least one rotatable roller of the row of rollers. Accordingly, the at least one rotatable roller is not continuously braked, which thus prevents continuous heat formation in the at least one rotatable roller of the row of rollers. 
     Advantageously, the magnet holder of the braking apparatus is shifted from a first position, in which the magnet holder of the braking apparatus is in an inactive state, at least into a second position, in which the magnet holder of the braking apparatus is in an activated state before the previously described braking of the at least one rotatable roller of the row of rollers in the straightening device. 
     The braking apparatus preferably exerts a braking effect on the at least one rotatable roller of the at least one row of rollers in the straightening device contactlessly. This prevents the generation of heat due to mechanical friction, so that the at least one rotatable roller has a long service life and consequently a long maintenance service interval. 
     A cable processing machine according to the invention comprises a straightening device such as described previously. As described herein, a cable processing machine comprises various processing operations, such as cutting to length, insulation stripping, crimping, twisting and tin-plating. In order to ensure that these processing operations can be completed without interruption, formation of a loop between the straightening stand and the line drawing device is prevented with the aid of the straightening device as described herein. 
     In particular, the straightening device as described previously is arranged immediately after a container. Typically, continuous lines are drawn into a cable processing machine, and the line lengths thereof are aligned and processed further there in the abovementioned processing operations, in particular being cut to a desired length. 
     A control device for controlling the braking apparatus is preferably present. The control device is designed to shift at least a portion of the braking apparatus from a first position, in which the braking apparatus is in an inactive state, at least into a second position, in which the braking apparatus is in an activated state. 
     In particular, the control device for controlling the braking apparatus is designed as a selector switch, with which the braking apparatus can either be kept permanently in the activated state, or with which the braking apparatus can be kept alternately in the inactive or the activated state, wherein the braking apparatus is accordingly shifted from the first position into the second position according to the machine cycle of the straightening device or cable processing machine. 
     Alternatively or additionally, a control device for controlling the magnet holder of the braking apparatus is present. This control device is designed to shift at least the magnet holder of the braking apparatus from a first position, in which the magnet holder of the braking apparatus is in an inactive state, at least into a second position, in which the magnet holder of the braking apparatus is in an activated state. 
     Alternatively or additionally, a control device for controlling an electromagnet of the braking apparatus is present. This control device is designed to control the electric current in the electromagnet and thus adjust the magnetic field of the electromagnet. This enables the magnetic operative braking connection with the rotatable rollers of the at least one row of rollers to be adjusted steplessly. 
     Alternatively or additionally, the control device is designed to control the straightening stand. The movements of the first row of rollers and/or the second row of rollers in a straightening stand are typically controlled by means of the control device, so that the alignment of the line can be carried out in a controlled and reproducible manner. Control of the braking apparatus and the straightening stand such as described herein with a control device enables the braking of the at least one rotatable roller on the straightening stand to be matched with the movement of the first and/or second row of rollers on the straightening stand when aligning the line. 
     In particular, the cable processing machine has at least one further straightening stand as described earlier, wherein the at least one further straightening stand is arranged at an angle of 90° with respect to the first straightening stand, and the two straightening stands are arranged apart from and close to one another. 
     An arrangement at an angle of 90° to each other is understood—as described herein—to mean the arrangement of the axis of rotation of the rollers of the first straightening stand rotated through 90° relative to the axis of rotation of the rollers of the second straightening stand. This enables an improved alignment of the line in a first spatial direction and in a further spatial direction, the two spatial directions being arranged with an angular shift of 90° relative to each other. 
     The cable processing machine advantageously includes a line drawing device, which is arranged in a subordinate position in the delivery direction after the straightening device as described previously. In this way, the line which is be aligned can be drawn simply and automatically through the straightening device as described herein. 
     An upgrade kit according to the invention for a cable processing machine comprises a braking apparatus for braking at least one of the rotatable rollers in at least one row of rollers on the straightening stand, in particular for braking multiple rotatable rollers in at least one row of rollers of the straightening stand, such as is described herein. In this way, a straightening stand of a cable processing machine may be upgraded simply with a braking apparatus such as described herein. 
     The upgrade kit preferably comprises a control device such as is described herein which is connected to the braking apparatus such as described herein in order to control the braking apparatus such as described herein. 
     Further advantages, features and particularities of the invention may be discerned from the following description, in which exemplary embodiments of the invention are described with reference to the figures. Enumerations such as first, second, third or more are used solely for the purpose of identifying the components. 
     The list of reference numerals constitutes a component of disclosure in the same way as the technical content of the claims and the figures. The figures are described individually and with correlation to the other figures. The same reference numerals stand for identical components, reference numerals with different indices denote functionally equivalent or similar components. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the Drawing: 
         FIG. 1  is a perspective view of a first embodiment of a straightening device according to the invention, 
         FIG. 2  is a perspective view of the straightening device of  FIG. 1 , wherein the straightening stand is shown separated from the braking apparatus, 
         FIG. 3  is a side view of the straightening device of  FIG. 1 , wherein the braking apparatus is arranged in an inactive state, 
         FIG. 4  is a side view of the straightening device of  FIG. 1 , wherein the braking apparatus is arranged in an activated state, 
         FIG. 5  is a cross-sectional view of a roller of one of the rows of rollers of the straightening stand in the straightening device of  FIG. 1 , 
         FIG. 6  is a perspective view of a cable processing machine having a straightening device according to the invention as shown in  FIG. 1 , 
         FIG. 7  is a perspective view of the straightening device according to the invention as shown in  FIG. 1 , and a further straightening device on the cable processing machine of  FIG. 6 , and 
         FIG. 8  is a perspective view of an upgrade kit according to the invention for a cable processing machine. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  to  FIG. 5  show a straightening device  15  for aligning an electrical or optical line  11  in a straightening stand  20  along a delivery route  16 . The straightening stand  20  comprises a straightening stand housing  22 , on which a first row of rollers  21  with multiple rotatably mounted rollers  25  is arranged, and on which a second row of rollers  31  with multiple rotatably mounted rollers  35  is arranged. In these figures and in the following figures, one roller  25  will be marked with the respective reference numeral to represent the plurality of rollers  25  and one roller  35  will be marked with the respective reference numeral to represent the plurality of rollers  35 . The straightening stand  20  represented is in the closed state, in which the two rows of rollers  21  and  31  are positioned in close proximity to each other, and wherein the line  11  is guided between the rollers  25  and the rollers  35  and rests on the rollers  25  along a delivery direction  17 . The rollers  25  are in a staggered arrangement relative to the rollers  35  along the delivery direction  17 . The first row of rollers  21  is arranged on a first carrier  23 , and the second row of rollers  31  is arranged on a second carrier  33 . The two carriers  23  and  33  are attached to the straightening stand housing  22 . The straightening stand  20  comprises a positioning drive  27  and a swivel drive  28 . In this case, the positioning drive  27  comprises a pneumatically controlled drive and moves the first row of rollers  21  up to the second row of rollers  31  in such manner that the distance between the first row of rollers  21  and the second row of rollers  31  may be reduced until the rollers  35  of the second row of rollers  31  touch the line  11  and hold the line  11 , or until the line  11  is clamped between the rollers  25  and the rollers  35 . The swivel drive  28  comprises an adjustment spindle  29 , which swivels the first row of rollers  21  through a definable angle relative to the second row of rollers  31 , so that a section of the line to be aligned is clamped or retained in the straightening stand  20 . 
     The straightening device  15  includes a magnetic braking apparatus  40  for braking the rotatable rollers  25  of the first row of rollers  21  in the straightening stand  20 . The braking apparatus  40  includes a magnet holder  45  having multiple permanent magnets  41 - 44 , wherein permanent magnets shown here have a cylindrical structure and are neodymium magnets. The magnet holder  45  is located at a distance from the rotatable rollers  25 , and in an activated state is in a contactless operative braking connection with the rotatable rollers  25  of the first row of rollers  21  in the straightening stand  20 . The braking apparatus  40  is also embodied as an eddy current brake, which exerts a braking effect on the rotatable rollers  25  during alignment of the line  11 . In this context, the braking apparatus  40  acts in particular on the outer ring  25   a  of the rotatable rollers  25 . 
     The braking apparatus  40  includes a positioning apparatus  50  for moving the magnet holder  45  and comprises a housing  51  and a guide section  52  arranged on the housing  51 . The positioning apparatus  50  has a drive device  55 , which shifts the magnet holder  45 —in the present case pneumatically—relative to the at least one rotatable roller  25  or the multiple rotatable rollers  25 . The positioning apparatus  50  moves the magnet holder  45  from a first position, in which the magnet holder  45  is in an inactive state (see  FIG. 3 ), into a second position, in which the magnet holder  45  is in an activated state (see  FIG. 4 ). The positioning apparatus  50  is designed to move the magnet holder  45  horizontally, which here means substantially normally to the axis of rotation  26  of the rotating roller  25 . 
     The positioning apparatus  50  has an end plate  57 , which is arranged on the housing  51  with the aid of cylindrical bars  59 . The magnet holder  45  has boreholes which accommodate the cylindrical bars  59  singly. The magnet holder  45  is mounted on the cylindrical bars  59  so as to be movable towards the end plate  57 . Pretensioning springs  58  are arranged on the cylindrical bars  59  and they bias the magnet holder  45  against the housing  51 , so that tilting of the magnet holder  45  when the magnet holder  45  is transferred from a first position to a second Position can be prevented. 
     The braking apparatus  40  is connected to a control device  80  for controlling the braking apparatus  40 . The control device  80  is connected to the positioning apparatus  50  via control lines  81  and is designed to shift the magnet holder  45  from a first position, in which the braking apparatus  40  and die magnet holder  45  is in an inactive state, at least into a second position, in which the magnet holder  45  is in an activated state. In this way, a contactless operative braking connection may be adjusted between the permanent magnets  41 - 44  and the rotatable rollers  25  when aligning the line  11 . In this context, the contactless operative braking connection acts primarily on the outer ring  25   a  of the rotatable rollers  25 . 
       FIG. 5  shows the rotatable roller  25  which is arranged on the row of rollers  21  on the straightening stand  20 . The rotatable roller  25  includes an inner ring  25   b  and an outer ring  25   a . A ball race is arranged between the inner ring  25   b  and the outer ring  25   a  as rolling element unit  25   c . The inner ring  25   b  serves to fasten the ball race securely on the arbor  30  of the row of rollers  21  on straightening stand  20 , the inner ring  25   b  being arranged fixedly on said arbor  30 . The rotatable outer ring  25   a  is arranged on said arbor  30  via the rolling element unit  25   c  so as to be rotatable about the axis of rotation  26  and rotates in accordance with the line drawing speed. The rotatable outer ring  25   a  has a groove  32  to enable centred guidance of the line  11  that is to be aligned. The rollers  35 , which are positioned on the row of rollers  31  by means of an arbor, are constructed identically to the rollers  25 . 
     In an alternative embodiment, the rollers are each arranged on the row of rollers fixedly on rotatable arbors. In this arrangement, the arbors rotate with the rollers about the axis of rotation, so the lines can be aligned in the straightening stand (not shown). 
     A further variant of the inventive magnetic braking apparatus (not shown here) is equipped with an electromagnet instead of the previously described permanent magnets. The magnetic field strength can be modified with the aid of the control device to adjust the magnetic operative braking connection. 
     The method for braking the rotatable rollers  25  in the straightening device  15  will now be described with reference to  FIG. 1 ,  FIG. 3  and  FIG. 4 . 
     First, the line  11  to be aligned is unwound from a container, drawn by hand into the straightening device  15  and placed on the straightening rollers  25  of the first row of rollers  21 . At this point, the straightening stand  20  is initially in an opened state, so the two rows of rollers  21  and  31  are located sufficiently far away from each other. In a further step, the straightening stand  20  is with positioned with the positioning drive  27  so that the rollers  35  of the second row of rollers  31  subsequently rest on the line  11 . In addition, the second row of rollers  31  is swivelled with the aid of the swivel drive  28  and pressed onto the line  11 . Then, the line  11  is aligned, wherein the line  11  is drawn through the straightening device  15 . The line is drawn in by a power-driven line drawing device, which is arranged at a distance from the straightening device  15  in the delivery direction (see  FIG. 7 ). At this time, the rollers  25  of the first row of rollers  21  and the rollers  35  of the second row of rollers  31  are caused to rotate. For the purpose of braking, the magnet holder  45  of the braking apparatus  40  is shifted from a first position, in which the magnet holder  45  of the braking apparatus  40  is in an inactive state (see  FIG. 3 ), into a second position, in which the magnet holder  45  of the braking apparatus  40  is in an activated state (see  FIG. 4 ). In the inactive state, the magnet holder  45  is in immediate proximity to the end plate  57 , and the pretensioning springs  58  are in the compressed state. In the activated state, the magnet holder  45  is located directly below the rotating rollers  25 , and the pretensioning springs  58  are in an unloaded state. In a further step, the effective braking of the rotating outer rings  25   a  of the rollers  25  of the first row of rollers  21  with the permanent magnets arranged on the magnet holder  45 , wherein the braking apparatus acts in braking manner on the rotating outer rings  25   a  of the rollers  25  without touching them, according to the principle of the eddy current brake. Thus, the braking apparatus  40  is in an operative braking connection with the rotating outer rings  25   a  of the rollers  25 . 
     In an alternative embodiment, the rotatable rollers are each arranged on a rotating axle on the row of rollers in the straightening stand and are attached fixedly to said rotatable axle. The rotatable axle rotates about an axis of rotation together with the roller arranged thereon, wherein said axis of rotation extends along the longitudinal extension of the rotatable axle. In this context, the contactless braking effect acts on the rotating rollers of the respective row of rollers (not shown). 
       FIG. 6  shows a cable processing machine  70  according to the invention, having a straightening unit and a straightening device  15  such as described previously. As described here, the cable processing machine  70  may be designed to perform various processing operations, such as aligning, cutting to length, insulation stripping, crimping, twisting and tin-plating. A container  75  containing a line  11  in the form of a continuous line is arranged in front of the straightening device  15 . The line  11  is drawn into the cable processing machine  70  and is aligned in the straightening device  15 . Aline drawing device  90 , which is arranged in a subordinate position in the delivery direction after the straightening device  15  is used to draw the line  11  through the straightening device  15  as will be described below. 
       FIG. 7  shows the straightening unit  73  with two straightening devices  15  and  15   a  arranged side by side, each of which has two straightening stands  20   a - 20   d . One of these straightening devices  15 ,  15   a  includes a braking apparatus  40  such as described herein for braking the rotatable rollers in one of the rows of rollers in the straightening stand  20   a . The cable processing machine  70  has a control device  80  such as described herein for controlling the braking apparatus  40  of the straightening device  15 . Additionally, the control device  80  is connected electrically to the positioning drive, the swivel drives of the straightening stands  20   a  and  20   c , and to a line drawing device  90  via the control lines  81 . The line drawing device  90  of the cable processing machine  70  draws the line  11  in delivery direction  17  through the straightening stands  20   a  and  20   c . The control device  80  contains a processor  85  which processes the control commands and transmits them to the drive device  27 ,  28  and  55 , to the line drawing device  90 , and to the braking apparatus  40  and/or the straightening stands  20   a  and  20   c . In this context, the control commands are transmitted to the drive devices  55 , the line drawing device  90  and braking apparatus  40 , and to the drive devices  27 ,  28  of the straightening stands  20   a  and  20   c  according to a predefined step sequence. The two straightening stands  20   a  and  20   c  in a position rotated through 90° relative to each other. In an embodiment of the straightening unit which is not shown, any of the straightening stands  20   a - 20   d  shown in  FIG. 7  may include a braking apparatus, such as described herein. 
       FIG. 8  shows an upgrade kit  100  according to the invention for a cable processing machine, wherein the kit contains a braking apparatus  40  such as described herein for braking at least one of the rotatable rollers in a row of rollers in a straightening stand, in particular for braking multiple rotatable rollers in a row of rollers in a straightening stand. The upgrade kit  100  includes a control device  80  with a processor  85 , which is connected to the drive device  55  of the positioning apparatus  50  in order to control the braking apparatus  40 . 
     LIST OF REFERENCE NUMERALS 
     
         
           11  Line 
           15  Straightening device 
           15   a  Straightening device 
           16  Delivery route 
           17  Delivery direction 
           20  Straightening stand 
           20   a - 20   d  Straightening stands 
           21  First row of rollers 
           22  Straightening stand housing 
           23  First carrier 
           25  Rollers of  21   
           25   a  Outer ring of  25   
           25   b  Inner ring of  25   
           25   c  Rolling element unit of  25   
           26  Axes of rotation of  25   
           27  Positioning drive 
           28  Swivel drive 
           29  Adjustment spindle 
           30  Arbor of  25   
           31  Second row of rollers 
           33  Second carrier 
           32  Groove of  25   a    
           35  Rollers of  31   
           40  Braking apparatus 
           41 - 44  Permanent magnets 
           45  Magnet holder 
           50  Positioning apparatus 
           51  Housing of  50   
           52  Guide section 
           55  Drive device 
           57  End plate 
           58  Pretensioning springs 
           59  Cylindrical bars 
           70  Cable processing machine 
           73  Straightening unit 
           80  Control device 
           81  Control lines 
           85  Processor 
           90  Line drawing device 
           100  Upgrade kit