Patent Publication Number: US-8978435-B2

Title: Wire straightening apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to European Patent Application No. 10167053.7, filed Jun. 23, 2010, which is incorporated herein by reference. 
     FIELD 
     The disclosure relates to a straightening apparatus for straightening wires and a corresponding method. 
     BACKGROUND 
     To allow reliable execution of process steps on a wire-processing machine, such as insulation-stripping, crimping, and end-fitting, wires that are straight are important. 
     To make the wires straight, they are generally pulled, with the aid of the drives that are present in the wire-processing machine, through one or more straightening apparatuses that are mounted at the run-in of the machine. Curvatures and twists in the wires are thereby eliminated. 
     Known straightening apparatuses can require great outlay to yield a given straightening effect. With the usual straightening apparatuses in wire-processing machines, it can be difficult to reproduce a setting on the same straightening apparatus, or on another straightening apparatus, or on another machine. 
     Known straightening apparatuses usually have a plurality of rolls, between which the wire that is to be straightened is led. They also employ former solution methods for setting the roll-distance, which can use engraved scales and setting screws, in some cases with counters. In some cases, it is also possible to set the roll-distance automatically by means of an actuator. The rolls of the formerly known straightening apparatuses typically sit on two roll-rails. Setting of the pull-in of the straightening apparatus, i.e. the inclination of one or both roll-rails, usually takes place by tight gripping with screws. Frequently, this setting is performed using a rule of thumb which states that the exit-side rolls of the straightening apparatus should touch the wire. Due to the lack of simple setting possibilities and simple setting criteria, the pull-in is often not changed. 
     For straightening apparatuses there are therefore to date no known simple, robust criteria or parameters which, for example, can be stored together with a wire, so as to make it possible to optimally set the straightening apparatus on an arbitrary machine according to the wire type. 
     The rolls of straightening apparatuses that are used today are set with simple means to a certain position that depends on the material that is to be straightened. However, this position is very critical. A small incorrect setting, or a small deviation of the external diameter (e.g. caused by production scatter in the wire manufacture), or of the elasticity in the wire (e.g. depending on the temperature when processing), causes greatly differing straightening results. 
     Inexpensive straightening apparatuses today are set with a parameter, viz, a feeding movement of a rail with rolls perpendicular to the wire. 
     A straightening apparatus is described in EP0932462 (see also WO 98/12005). This document proposes arrangement of a first row of rolls perpendicular to the axis of the wire. The pull-in results from the arrangement of a second row of rolls which, through being borne in floating manner, is to a small extent additionally modifiable in its angular position. The change in angle is, however, largely undefined, since it is determined by two compression springs, which also serve to open the straightening apparatus. In addition, the pre-tensioning of these springs is modified by adjustment of the distance between the rows of rolls. 
     A further straightening apparatus is known from EP 0 739 066 A2. The straightening apparatus according to EP 0 739 066 A2 makes use of roll arrangements which, by swiveling movements, are settable in both horizontal and vertical direction. 
     SUMMARY 
     The disclosed embodiments relate in particular to straightening apparatuses for wire-processing machines. The wires, for example, insulation-stripped strands or complete conductors of copper or steel, which are processed on a wire-processing machine, are usually made ready in drums, on rolls, or as bundles, and, for this reason, after unrolling, are often to a greater or lesser extent curved and possessed of twist. 
     Embodiments of the technologies disclosed herein comprise an entry-side roll arrangement and an exit-side roll arrangement. These roll arrangements are arranged in such manner that, viewed in the direction of transport, a wire that is to be straightened enters into the straightening apparatus between the rolls of the entry-side roll arrangement and, after passing through, leaves the straightening apparatus between rolls of the exit-side roll arrangement, the straightening apparatus being settable in, for example, two degrees of freedom. Settable as first degree of freedom is a distance between two rolls of the exit-side roll arrangement, and specifiable as second degree of freedom is a force that acts perpendicular to the direction of transport on the wire between two rolls of the entry-side roll arrangement. 
     In former straightening apparatuses it is at least sometimes neglected that, to obtain an optimal straightening result, the aforesaid pull-in should be changed according to the material that is to be straightened. For the first time, at least some embodiments disclosed herein offer the possibility of reproducibly specifying and setting two degrees of freedom. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is explained in more detail by reference to the attached figures. Shown are in 
         FIG. 1  a first embodiment in a diagrammatic representation; 
         FIG. 2  a second embodiment in a diagrammatic representation; 
         FIG. 3  a diagrammatic three-dimensional representation of an embodiment of a straightening apparatus; 
         FIG. 4A  a diagrammatic plan view of the straightening apparatus according to  FIG. 3 ; 
         FIG. 4B  a diagrammatic cross section along the axis A-A of the straightening apparatus according to  FIG. 4A ; 
         FIG. 5  a diagrammatic side-view of an embodiment of a straightening apparatus in an open state; 
         FIG. 6  a diagrammatic side-view of an embodiment of a straightening apparatus in a closed state; 
         FIG. 7  a diagrammatic side-view of an embodiment of a straightening apparatus in an active state; 
         FIG. 8  a diagrammatic three-dimensional view of a further embodiment of a straightening apparatus; 
         FIG. 9A  a diagrammatic side view of a further embodiment of a straightening apparatus; and 
         FIG. 9B  a diagrammatic three-dimensional view of the straightening apparatus according to  FIG. 9A . 
     
    
    
     DETAILED DESCRIPTION 
     The term “entry-side roll arrangement  110 ” is used for an arrangement of two, three, or more rolls (e.g. the rolls  111 - 113  in  FIG. 1  or  FIG. 2 ). The term “exit-side roll arrangement  120 ” is used for an arrangement of two, three, or more rolls (e.g. the rolls  121 - 124  in  FIG. 1  or  FIG. 2 ). “Entry side” means that the corresponding arrangement is one which, in relation to the direction of transport X of the wire  1 , is located before the rolls of the exit-side roll arrangement  120 . In other words, the wire  1  first runs between the rolls of the entry-side roll arrangement  110 , and only then between the rolls of the exit-side roll arrangement  120 . 
     Either the rolls of the entry-side roll arrangement  110  are held by a first pair of distanced roll-plates, and the rolls of the exit-side roll arrangement  120  by a second pair of distanced roll-plates. In this case, the mechanical outlay is, however, generally greater than in an embodiment which is based on the principle shown in  FIG. 2 , in which a first roll-plate  130  bears some of the rolls (here the rolls  111 ,  113 ) of the entry-side roll arrangement  110  and some of the rolls (here the rolls  121 ,  122 ) of the exit-side roll arrangement  120 , and a second roll-plate  140  bears some other of the rolls (here the roll  112 ) of the entry-side roll arrangement  110  and some other of the rolls (here the rolls  123 ,  124 ) of the exit-side roll arrangement  120 . 
     Generally, the principle shown in  FIG. 2  is mechanically simpler to implement, since only the distance d and the force F (which result in a pressure that acts on the wire  1 ) of the two roll-plates  130 ,  140  must be moved relative to each other in specifically controlled manner. In an embodiment with, for example, four roll-plates, the setting/adjustment outlay is generally somewhat greater. 
     Two basic straightening apparatuses  100  which, for the purpose of straightening wires  1 , are equipped with an entry-side roll arrangement  110  and an exit-side roll arrangement  120 , are shown in  FIGS. 1 and 2 . The roll arrangements  110 ,  120  are arranged in such manner that, viewed in the direction of transport X, a wire  1  that is to be straightened arrives in the straightening apparatus  100  between rolls  111 ,  112 ,  113  of the entry-side roll arrangement  110 . After passing between the rolls  121 ,  122 ,  123 ,  124  of the exit-side roll arrangement  120 , the wire  1  leaves the straightening apparatus  100 . 
     In some embodiments the straightening apparatus  100  is particularly characterized in that it is settable in two degrees of freedom d, F. This settability can be selected or designed so that the settability is reproducible, i.e. is generally reconstructable at any time based on instructions. 
     The various embodiments of the disclosed technologies can also have more rolls, or fewer rolls, than shown in the figures. 
     Described below are embodiments that were all derived from the principle that is shown in  FIG. 2 . The technical theory of this embodiment can, however, also be transferred to the principle of  FIG. 1 . 
     The straightening apparatus  100  can comprise a baseplate  101 , arranged on which are an upper roll-plate  130  and a lower roll-plate  140 . In their starting state, the rolls of the two roll-plates  130 ,  140  are each arranged parallel to an ideal wire-axis (which lies parallel to the direction of transport X) of a wire  1 . The rolls possibly have in the center a continuous circumferential groove. In  FIG. 4A , for example, the groove  123 . 1  of the roll  123  is indicated by an arrow. 
     It should be noted that, in  FIGS. 3 to 9B , in each case only those rolls are provided with reference numbers to which reference is made in the current description. As already mentioned, the number of rolls can vary, depending on the embodiment. The assignment of the rolls to the entry-side roll arrangement  110 , and to the exit-side roll arrangement  120 , relates at least to the first two or three entry-side rolls  111 ,  112 ,  113 , and to the last two or three exit-side rolls  121 ,  122 ,  123 . 
     In at least some embodiments, the rolls can be arranged mutually offset. They can be in sequence of, for example, an upper roll  111 , then diagonally a lower roll  112 , and then diagonally an upper roll  113 , etc. The number of the lower rolls  112 ,  124 ,  123  can be one less than the number of the upper rolls  111 ,  113 ,  121 ,  122  (e.g. above four rolls, and below three rolls, as in  FIGS. 1 and 2 ), or vice versa (e.g. above four rolls, and below five rolls, as in  FIG. 3 ). 
     The upper roll-plate  130  can be led with a guide  102  perpendicular to the wire-axis (direction of transport X) on the baseplate  101 , as can be seen in the cross-sectional representation in  FIG. 4B . It can be pressed into the open state (i.e. here upwards) with a spring  103 . A rapid-clamping lever  104  with eccentric  104 . 1 , or a corresponding automatically operable eccentric element, can serve to rapidly open and close the upper roll-plate  130 . “Opening” is the designation given to a relative movement which results in the distance between the upper roll-plate  130  and the lower roll-plate  140  being enlarged. “Closing” is the designation given to an opposite relative movement. During “opening” and “closing”, the respective roll-plates  130 ,  140  move synchronously. 
     The rapid-clamping lever  104 , the eccentric  104 . 1 , and the upper roll-plate  130  are, for example, displaced with a setting wheel or a setting screw  144  via a spindle  144 . 1  (see  FIG. 4B ) perpendicular to the wire-axis (direction of transport X). 
     The lower roll-plate  140  is swivelable about an off-center axis  141 . This axis  141  possibly lies close to the axis of rotation R 1  of the final roll  123  of the exit-side roll arrangement  120 . Generally, the closer the axis  141  sits to the axis of rotation R 1  of the final roll  123 , the less the distance d of the two final rolls  122 ,  123  changes when a slight swiveling movement of the lower roll-plate  140  about the axis  141  takes place. 
     In another embodiment, the axis  141  and the axis of rotation R 1  of the final roll  123  coincide. In this case, the distance d does not change when the lower roll-plate  140  executes a slight swiveling movement about the axis  141 . 
     The aforesaid swiveling movement about the axis  141  is executed to determine on the entry-side a force F, as can be seen, for example, in  FIG. 2  or  FIG. 5 . 
     To pull the roll-plate  140  upwards, a pneumatic cylinder  142 , for example, can be used. By the aforesaid turning movement about the axis  141 , the lower roll-plate  140  is thereby set diagonal relative to the upper roll-plate  130 , and the entry-side rolls press on the wire  1 , which is pulled through the straightening apparatus  100 . The apparatus  100  thereby exercises a reducing straightening effect in the direction of transport X (direction of pull) of the wire  1  from the first roll  111  to the final roll  122 . If the cylinder  142  acts in the opposite direction, the lower roll-plate  140  is moved parallel to the upper roll-plate  130  to a stop  143  into the starting position. The pneumatic cylinder  142  can be controlled by the wire-processing machine or straightening apparatus  100  via a valve. The pressure of the cylinder  142 , and hence also the force F is, for example, set via a pressure regulator. 
     An exemplary embodiment of the functional principle is explained below. 
     The straightening apparatus  100  has three positions:
     1. Open, when the two roll-plates  130  and  140  are set so that none of the rolls touches the wire  1  (see  FIG. 5 ).   2. Closed, when the roll-plates  130  and  140  are aligned parallel, and the rolls touch the wire  1  (see  FIG. 6 ).   3. Active, when the roll-plates  130  and  140  on the side of the first roll  111  (i.e. on the entry side) are pressed together with a force F, so that the wire  1  is straightened as it passes through (see  FIG. 7 ).   

     The wire-processing machine, or the straightening apparatus  100 , possibly sets the two roll-plates  130 ,  140  parallel with the pneumatic cylinder  142 . The operator, or a control, opens the straightening apparatus  100  with the rapid-clamping lever  104  and inserts the wire  1 . The operator, or a control, then closes the straightening apparatus  100  with the rapid-clamping lever  104  and sets, for example with the setting screw  144 , the upper roll-plate  130  so that all rolls of the apparatus  100  exactly touch the wire  1  (see  FIG. 6 ). The operator, or a control, can recognize this in that, for example, the wire  1  starts to bend. Alternatively, or additionally, during closing, the wire  1  can be moved backwards and forwards until the rolls turn with the wire  1 . The instant can thus be recognized which corresponds to the closed position  2  (see  FIG. 6 ). 
     With a pressure regulator, the operator or a control sets the pressure of the pneumatic cylinder  142  based on specifications (e.g. based on a table, or based on data from a storage medium) for the stretched-in wire  1 . The pressure of the pneumatic cylinder  142  corresponds to a force F, as described. 
     Before the wire-processing machine, or the straightening apparatus  100 , transports the wire  1  in the direction of transport X, the pneumatic cylinder  142  is brought into the upper position (referred to as “active position”), whereby the straightening apparatus  100  is active, and the wire  1  is bent by the upper and lower rolls in alternate directions, and decreasingly in the direction of wire-transport X, from the first roll  111  to the final roll  122 . As the wire  1  is pulled through the straightening apparatus  100 , it is now straightened in a defined manner. 
     When, after straightening, the wire  1  becomes stationary again, the wire-processing machine or straightening apparatus  100  can move the roll-plates  130 ,  140  apart again and set them parallel (referred to as “open position”), so that the wire  1  can be de-tensioned and removed. 
     The embodiments described hitherto can be modified, for example, as follows. 
     As already indicated, the axis of rotation  141  of the roll-plate  140  can assume another position. If the axis of rotation  141  of the lower roll-plate  140  coincides with the axis of rotation R 1  of the final roll  123 , the final roll  123  touches the wire  1  at all angular settings, or rotational settings, of the lower roll-plate  140 , provided that in Step  2  the closed setting was moved to/set. This principle can be applied to one or more embodiments disclosed herein. 
     In some cases, to ensure that, even in the case of a slightly faulty setting of the upper roll plate  130 , the final roll  123  no longer bends the wire  1 , the axis of rotation  141  can be located below the axis of rotation R 1  of the roll  123 . 
     Similar to the lower roll-plate  140 , the upper roll-plate  130  can be provided with an axis of rotation which coincides with the roll-axis of the final roll  125  of the upper roll-plate  130 , or lies in the vicinity of this roll  125  in  FIG. 3A , with the possible advantage that the wire  1 , on entry to the straightening apparatus  100 , is symmetrically loaded. This principle can be applied to one or more disclosed embodiments. 
     As explained below, it is possible for the upper roll-plate  130  to be provided with a setting aid. If the external diameter of the wire  1  is known, the upper roll-plate  130  can be brought into a defined position, e.g. with a scale, which is inscribed for various wire dimensions, or with a sensor, which measures the distance of the two roll-plates  130 ,  140  from each other. A position transducer or distance sensor can be used as sensor. As shown in  FIG. 6 , the setting aid can allow the transition from the open setting into the closed setting to be made reproducible. This principle can be applied to one or more disclosed embodiments. 
     Depending on the embodiment, a force sensor  145  can be provided as shown in  FIG. 8 . A force sensor  145  can be built in which allows measurement of whether the wire  1  is touching the rolls, or the rolls touching the wire  1 , respectively. For example, a force sensor  145  can measure the contact via a measurement roll  105  and a counter roll  106 . The rolls  105  and  106  can touch the wire  1  in a line with the other rolls of the respective roll-plate  130 ,  140 . This principle can be applied to one or more disclosed embodiments. 
     Depending on the embodiment, a position sensor can be provided. A corresponding roll  107 . 1  can be mounted on a lever  108 , which, via an axle  108 . 1 , is rotatably fastened to the roll-plate  130 . With a spring  108 . 2 , or through gravity, the lever  108  is pressed in the direction of an oppositely lying roll  107 . 2 . Through the contact with the wire  1 , the roll  107 . 1  is moved into the line of the other rolls of the upper roll-plate  130 . A sensor which is fastened on the roll-plate  130  (e.g. a fork light-barrier  109 ) emits a signal if the roll  107 . 1 , which touches the wire  1 , is located in a line with the other rolls of the upper roll-plate  130 , and therefore all of the rolls touch the wire  1 . This principle can be applied to one or more disclosed embodiments. 
     Instead of, or in addition to, a sensor (e.g. a fork light-barrier  109 ), a marking can also be applied to the upper roll-plate  130 , which, on manual setting, shows the correct position of the lever  108 . This principle can be applied to one or more disclosed embodiments. 
     Possibly, a return of sensor data into the straightening apparatus  100  is applied. In this manner, a closed-loop, or active, control circuit can be established. For this purpose, the sensor signals of the force sensor or position sensor can be fed into, for example, a machine control of the straightening apparatus  100  and/or of the wire-processing machine, which monitors the measurement values and, in case of faulty settings, for example, warns the user and blocks the wire processing. This principle can be applied to one or more disclosed embodiments. 
     In some cases, a feeding mechanism of the upper roll-plate  130  is used. The upper roll-plate  130  can be moved by motor, e.g. with a motor  131  with spindle  132 . The motor drive can be coupled with one of the said sensors (e.g.  145  and/or  109 ), to automatically travel to the optimal position, in which both the distance d and the force F match the specified values. 
     The feeding force or pressure that is responsible for creating the force F can, in one or more embodiments, be applied also to the lower roll-plate  140 , or both roll-plates  130 ,  140  can have applied to them a partial force. 
     To specify the force F, instead of a manual pressure regulator, in each embodiment also a pressure-regulating valve can be used, which can be controlled by the wire-processing machine or the straightening apparatus  100 . The wire-processing machine or the straightening apparatus  100  can maintain a table (e.g. in a storage medium), in which the optimal force F for the various types of wire, or the corresponding setting of the pressure-regulating valve, or of the cylinder of the apparatus  100 , is stored. In this case, setting of the pressure takes place at least partially automatically or fully automatically as soon as the wire-type of the wire-processing machine, or of the straightening apparatus  100 , is known. 
     In at least some embodiments, the force F can also be varied during the wire transport so as to straighten the wire  1  more or less strongly in various sections. 
     At least some of the disclosed embodiments offer an array of advantages, which have already been described or otherwise indicated. Example advantages of the straightening apparatus  100  can include:
         Easily settable parameters, which allow an optimal (manual or automatic) setting.   The parameter that defines the force F is insensitive, i.e. even with a slight deviation from the optimal force setting (through faulty setting, manufacturing tolerances, or deviating material characteristics), the straightening effect of the straightening apparatus  100  does not deviate far from the optimum.   The roll-distance parameter d at the exit can be derived objectively, and very easily, from the geometrical data of the material that is to be straightened (of the wire  1 ). In at least some cases, a faulty setting is therefore unlikely.   Both parameters F and d are objectively measurable and settable (manually or automatically).   Both parameters F and d are independent of a certain wire-processing machine or of a certain straightening apparatus  100 . The setting data can therefore be defined once and stored along with the wire type (e.g. in a storage medium). These setting data can be used with reproducible effect at an arbitrary point in time on an arbitrary wire-processing machine or straightening apparatus  100 .   In certain operating states, it is possible to reduce the entry-side force F, for example in the case of a stationary wire  1 , so as to avoid an undesired deformation in wire  1  or, at high speed, to reduce the necessary drive-power in the wire-advance. The wire  1  is nevertheless well-led between the rolls of the straightening apparatus  100 .   At least some embodiments of the straightening apparatus  100  can be inexpensively designed and constructed, and existing wire-processing machines can be easily retrofitted.   In at least some embodiments, the entry-side rolls of the straightening apparatus  100 , which often exercise the greatest straightening effect, are always located in an ideal position.       

     Having illustrated and described the principles of the disclosed technologies, it will be apparent to those skilled in the art that the disclosed embodiments can be modified in arrangement and detail without departing from such principles. In view of the many possible embodiments to which the principles of the disclosed technologies can be applied, it should be recognized that the illustrated embodiments are only examples of the technologies and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims and their equivalents. I therefore claim as my invention all that comes within the scope and spirit of these claims.