Abstract:
A bending device for rod-shaped workpieces having a bending head with a mandrel rotatable about a rotation axis, a cutting device for cutting the respective workpiece in a cutting plane, and a feed and straightening device for feeding the workpieces to the bending head, the cutting device capable of being moved along a travel path in the feed direction of the workpieces, with the bending head capable of being shifted between an operating position in which it is moved towards the workpiece and an inactive end position remote therefrom, the bending head, in order to assume its operating position, can be moved into the travel path of the cutting device, whereas, when assuming its inactive end position, it is positioned outside the travel path of the cutting device, and, when the bending head is situated in its inactive end position, the cutting device can be moved downstream on its travel path at least partly over the area of the operating position of the bending head.

Description:
[0001]    The present application claims priority to German Patent Application No. 10 2011 106 942.2 filed on Jul. 8, 2011, which said application is incorporated by reference in its entirety herein. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a bending apparatus for rod-shaped workpieces. 
       BACKGROUND OF THE INVENTION 
       [0003]    With bending devices it is frequently desired that there be only a short, straight end piece between the cutting plane and the last bend which the bending head produces. 
         [0004]    A bending device is known from EP 0 379 030 B1 (corresponding to DE 690 03 116 T2) in which upstream of the bending head, a cutting device is provided that can be moved in feed direction of the workpiece. It is thus possible to vary the distance between the end of the workpiece produced after cutting and the bending head. However, with this known bending machine, the cutting device, even in its position moved furthest towards the bending head, is still a clear distance from the bending head. As a result, there is in every case a relatively long straight end piece of the workpiece between the cutting point and the bending head. 
         [0005]    In DE 10 2009 024 075 A1, a bending device for rod-shaped workpieces is described in which the cutting device mounted upstream of the bending head can likewise be shifted in feed direction of the workpieces. The bending head is attached to the front end of the machine frame, wherein the cutting device can be moved up to a frontmost position in which it is situated immediately in front of the bending head. Although the cutting plane of the cutting device can thus be moved up fairly close to the bending head, in different cases of application this still leads to a straight end piece which turns out to be longer than desired. 
         [0006]    In order to still further shorten such relatively short straight end pieces between the last bend in the workpiece and its end, with known bending devices the workpiece has previously been moved backwards via the feeder (or a movable feeder) and the last bend already produced positioned at the cutting unit, in order to make a cut in this position. However, the required reversal of the conveyance direction of the workpiece leads to an undesired reduction in the machine&#39;s throughput. In addition, some bending devices also have no movable feeder, in which case it is not even possible to convey the workpiece backwards. Moreover, a rearward conveyance of the workpiece via the feeder is also very problematic when large workpiece diameters are used. 
       SUMMARY OF THE INVENTION 
       [0007]    As a result of the problems in the prior art, an object of the present invention is to provide a bending device such that it is also possible to cut off the workpiece quite close to its last bend with no, or only an extremely short, straight end piece, without the need for a movement of the workpiece. 
         [0008]    According to certain aspects of the present invention, this objective is achieved with a bending device for rod-shaped workpieces having a bending head, which in order to assume its operating position, can be moved into the travel path of the cutting device, whereas, after assuming its inactive end position, it lies completely outside the travel path of the cutting device, and in that, when the bending head is situated in its inactive end position, the cutting device can be moved downstream on its travel path at least partly over the area of the operating position of the bending head, i.e. the area of the travel path which the bending head occupies in its operating position. 
         [0009]    According to certain aspects of the present invention, a bending device for rod-shaped workpieces has a bending head with a mandrel rotatable about a rotation axis, a cutting device for cutting the respective workpiece in a cutting plane, and downstream of the bending head, a feed and straightening device for feeding the workpieces to the bending head, wherein the cutting device can be moved along a travel path in feed direction of the workpieces and the bending head can be shifted between an operating position in which it is moved up to the workpiece and an inactive end position remote therefrom. 
         [0010]    With the bending device according to certain aspects of the present invention, an arrangement is thus used in which the bending head can be shifted between an operating position in which it can process the workpiece and in which it protrudes into the travel path of the cutting device, and an inactive end position remote from the latter, wherein, when it assumes the inactive end position, it lies outside the travel path of the cutting device. The travel path of the cutting device extends downstream at least partly into the area of the operating position of the bending head or even beyond this area. 
         [0011]    In certain aspects of the present invention, if the bending head is in its operating position, it protrudes into an area of the travel path of the cutting device, with the result that in this situation the cutting device cannot be moved along its entire travel path, in order not to collide with the bending head in its operating position. However, if the bending head has been moved out of its operating position into its inactive end position, in which it is wholly situated outside the travel path of the cutting device, the cutting device can then also be moved as far as the downstream end of its travel path (seen in feed direction of the workpiece). This configuration makes it possible, after moving the bending head into its inactive end position, to move the cutting device (at least) partly over the area of the operating position of the bending head so far that it has moved right up to the beginning of the last bend formed by the bending head on the workpiece, and only there can it be activated for cutting. 
         [0012]    The bending device according to certain aspects of the present invention is particularly preferably designed such that the cutting device can be moved at least so far downstream over the area of the operating position of the bending head, i.e. the area occupied by the bending head in its operating position, that it can reach a movement end position in which the cutting plane lies downstream of the position assumed by the rotation axis of the mandrel of the bending head when the latter has been deployed into its operating position. In certain aspects, this embodiment allows the cutting device to be moved so far that it can quite safely be moved up to the beginning of the last bend in the workpiece formed by the bending head. 
         [0013]    In further certain advantageous aspects of the present invention, the bending device can be provided such that the cutting device can travel over the whole of the area of the operating position of the bending head when the latter is situated in its inactive end position, particularly preferably that the cutting device can even be moved further downstream beyond the area of the operating position of the bending head, particularly preferably it can even be moved as far as the end of the machine frame. Quite specific advantages of a bending device according to the present invention can be achieved with these embodiments. 
         [0014]    In certain aspects of the present invention, if the cutting device is arranged so that it can travel over the whole of the area of the operating position of the bending head, this provides the possibility that a workpiece can be lowered only in front at the end face of the machine, for which the bending part in question is moved out forward beyond the bench, the cutting device is moved as far as the end of its travel path over the area of the operating position of the bending head and optionally even as far as the end of the machine frame, thus as far as the edge of the bench, and only there is the cut activated (wherein in this case the bench recess must of course be correspondingly adapted). 
         [0015]    Completely different positions for depositing the processed workpieces can thus be achieved with the bending device according to the present invention. 
         [0016]    In certain aspects of the present invention, a further advantageous possibility is also provided if, before cutting, the workpiece is conveyed still further forward beyond the supporting bench of the machine onto a further support bench or other reception device and only then is the cutting device activated e.g. in a middle position or at the end of the bench, thus allowing particularly easy removal of the workpieces over the end face of the bending device. 
         [0017]    In certain aspects of the bending device according to the present invention, because by moving the bending head out of the travel path of the cutting device the possibility is created (solely by moving the cutting device into the area of the operating position of the bending head, or even beyond the latter) to place the cut where it is desired without the possibility of a collision with the bending head, workpieces with cuts that take place immediately at the last bend or very shortly before it can be produced without difficulty and without the workpiece having to be moved in any way. Since it is completely unnecessary to reverse the movement of the workpiece, not only is it possible to achieve a somewhat higher workpiece throughput with the bending device according to the present invention, but it can also be used for workpieces with relatively large diameters in the case of which a reversal of the movement of the feeder was previously simply not possible. 
         [0018]    In certain aspects of the present invention, the bending head can be brought from its active operating position into its inactive end position (and vice versa) in any suitable manner. However, it is quite particularly preferred if the bending head can be moved by being made to travel in the direction of the rotation axis of the mandrel out of its operating position into its inactive end position or vice versa. Then, after the last bending process has been carried out, the mandrel can quite simply be moved perpendicularly out of the previous bending plane and brought into its other end position without further corrective movements of the mandrel being required in order to allow departure from the bending plane without changing the position of the workpiece. 
         [0019]    A quite particularly preferred embodiment of the bending device according to certain aspects of the present invention also provides that the cutting device comprises a support arm aligned perpendicularly to the feed direction of the workpiece, which support arm has a movable cutting blade and a stationary counter-blade fixed to the support arm in the feed direction of the workpiece directly in front of this cutting blade, wherein the cutting plane is established between the two adjacent blades. Furthermore, the support arm protrudes into the feed axis of the respectively conveyed workpiece and the workpiece coming from the feed device can be cut through while passing the cutting blade and the counter-blade in the cutting plane established between the two. This results in a relatively simply structured embodiment of the bending device according to the present invention, which can be produced inexpensively and allows a problem-free implementation of the method according to the present invention. 
         [0020]    According to certain aspects of the present invention, a particularly preferred embodiment of the bending device furthermore comprises the bending head being situated in a bending-head housing from which it can be moved out in order to assume its active operating position and into which it can be moved in order to assume its inactive end position. With this embodiment, if it has assumed its inactive end position inside the bending-head housing, outside the latter, where the bending head is moved out in its active operating position, the cutting device can be moved on top of the bending-head housing, while the bending head is accommodated, protected from the processes, inside the bending-head housing during the movement of the cutting device. 
         [0021]    With such an embodiment, the support arm of the cutting device is preferably movably supported on linear guides at its end area facing away from the supplied workpiece against a rear wall of the machine frame or of the bending-head housing parallel to the workpiece. Thus, when displaced by the bearing on the back of the machine frame or bending housing, it can be guided precisely parallel to the workpiece, while the support arm, when moved, is guided above the machine frame or the bending-head housing respectively, at a distance therefrom and at the same time the area of the operating position of the bending head can be traversed without difficulty. 
         [0022]    In certain aspects of the present invention, the bending-head housing can preferably be formed such that it can also still be movably attached to the machine frame parallel to the feed direction of the workpiece. 
         [0023]    In certain aspects of the present invention, the bending apparatus for rod-shaped workpieces comprises a bending head having a mandrel rotatable about a rotation axis, the bending head moveable between an operating position, in which the bending head comprises an operating area and operably engages the respective workpiece, and an inactive end position remote therefrom, a feed device and a straightening device, the feed and straightening devices operably located in an axial direction from the bending head, and a cutting device for cutting the respective workpiece in a cutting plane, wherein the cutting device is configured such that it is moveable along a travel path in a feed direction of the workpieces from the feed and the straightening devices to the bending head, and wherein the bending head in the operating position is located in the travel path of the cutting device, and the bending head in the inactive end position is positioned outside the travel path of the cutting device such that the cutting device can be moved in a downstream direction on the travel path toward the location of the bending head such that the cutting device is capable of being located at least partly within the operating area of the bending head. 
         [0024]    In certain aspects, the cutting device is moveable in the downstream direction such that the cutting plane is located upstream of the position of the rotation axis of the mandrel of the bending head in its operating position. 
         [0025]    In certain aspects, the cutting device is moveable in the downstream direction such as to completely traverse the operating area of the bending head when the bending head is in the inactive end position. 
         [0026]    In certain aspects, the cutting device is moveable in the downstream direction such that at least a portion of the cutting device is located beyond the operating area of the bending head. 
         [0027]    In certain aspects, the cutting device is moveable in the downstream direction as far as an end of a machine frame of the bending apparatus. 
         [0028]    In certain aspects, the bending head is moveable between the operating position and the inactive end position along a direction of the rotation axis of the mandrel. 
         [0029]    In certain aspects, the cutting device comprising a support arm aligned generally perpendicular to the feed direction of the workpiece 
         [0030]    In certain aspects, the support arm has a movable cutting blade, and a stationary counter-blade, the cutting blade and the stationary counter-blade defining the cutting plane. 
         [0031]    In certain aspects, the stationary counter-blade is fixed to the support arm in the feed direction of the workpiece. 
         [0032]    In certain aspects, the support arm protrudes as far as the respectively conveyed workpiece. 
         [0033]    In certain aspects, the support arm of the cutting device is movably supported on one or more linear guides. 
         [0034]    In certain aspects, the bending head is situated in a bending-head housing from which it can be moved out in order to occupy its operating position and into which it can be moved to occupy its inactive end position. 
         [0035]    In certain aspects, the cutting device comprising a support arm aligned generally perpendicular to the feed direction of the workpiece, wherein the support arm is movably supported on one or more linear guides proximally located on a machine frame of the bending apparatus. 
         [0036]    In certain aspects, the bending-head housing is movably attached to the machine frame parallel to the feed direction of the workpiece. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0037]    The present invention is explained in more detail in principle by way of example with reference to the drawings, wherein: 
           [0038]      FIG. 1  shows a top diagrammatic perspective view of a bending device according to the present invention, the bending device having a supporting bench viewed at an angle from above from the front; 
           [0039]      FIG. 2  shows a perspective view of the bending device in  FIG. 1 , but viewed at an angle from the back and without a supporting bench; 
           [0040]      FIG. 3  shows a top perspective view of the machine from  FIGS. 1 and 2 , the bending device having the supporting bench removed and the bending device illustrated in the configuration after a bending process; 
           [0041]      FIG. 4  shows a top perspective view from  FIG. 3 , but in the cutting position; 
           [0042]      FIG. 5  shows a diagrammatic view of a detail of the upper part of the bending device from  FIGS. 1 to 4 , viewed in the direction parallel to the supporting bench, before the workpiece is fed into the bending head; 
           [0043]      FIG. 6  shows a diagrammatic view from  FIG. 5 , but after a cutting process; and 
           [0044]      FIG. 7  shows a diagrammatic view from  FIG. 5 , but with cutting device located in the cutting position. 
       
    
    
     DETAILED DESCRIPTION 
       [0045]      FIGS. 1 to 4  show a diagrammatic perspective representation of a bending device  1 , wherein in the view in  FIGS. 1 ,  3  and  4  the chosen viewing direction is at an angle from above from front to back, and in the view in  FIG. 2  the chosen viewing direction is at an angle from above from back to front. 
         [0046]    The bending machine  1  comprises a machine frame  2  and a housing  3  mounted thereon, in which a feed device  4  in the form of a roller feed with three pairs of series-connected rollers is rotatably mounted. 
         [0047]    Two straightening devices  5  offset by 90° to each other are situated at the back of the housing  3 , are connected to the rotatable feed device  4 , and can be twisted with the latter about the central axis of a workpiece  11  in the form of a wire. 
         [0048]    Arranged in front of the end face  6  of the housing  3  are a bending head  7 , bearing a mandrel  8  at the top, which is rotatable about a rotation axis  9  ( FIGS. 2 and 3 ), as well as a cutting device  10  which can be moved along a travel path in direction a (workpiece-feed direction). 
         [0049]    In the representation of  FIG. 1 , an inclined supporting bench  18 , which supports the workpiece  11  during production, rests on top of a bending-head housing  20 . Corresponding to the inclination of the supporting bench  18 , the bending head  7  and the cutting device  10  are also arranged equally inclined to the horizontal, in order that, after cutting, the finished workpieces  11  can drop down. The supporting bench  18  (not shown in detail in the figures) is height adjustable, and the entire bending-head housing  20  can also be moved parallel to the longitudinal direction of the workpiece  11  (also not shown in the figures). 
         [0050]    To show the structure of the bending device  1  clearly, the supporting bench  18  is no longer shown in  FIGS. 2 to 7 . 
         [0051]    The bending head  7  is mounted in the bending-head housing  20 , which has an opening  21  on top through which the bending head  7  can be moved into the bending-head housing  20  or moved out of it. The outward and/or inward movement takes place in a direction b (cf.  FIG. 3 ), namely in the direction of the rotation axis  9 , perpendicular to the wire  11 . In certain aspects, as illustrated in  FIG. 3 , the rotation axis  9  and/or direction b are generally perpendicular to the travel path direction a. 
         [0052]    Also situated on the bending-head housing  20  is the cutting device  10  which, as shown by  FIG. 2 , comprises a support arm  12  which has a movable cutting blade  14  and, directly next to the latter, a fixed counter-blade  13 . The two blades  13 ,  14  between them establish a cutting plane  22 , as can best be seen from the representations in  FIGS. 5 to 7 . The movable cutting blade  14  is driven via a motor  25 . In certain aspects, as illustrated in  FIG. 3 , the cutting plane  22  is parallel to the rotation axis  9  and/or direction b, and when moved in travel path direction a as shown in  FIG. 4 , can be in the same plane as rotation axis  9 . Thus, in certain aspects, the cutting plane  22  is generally perpendicular to the travel path direction a. 
         [0053]      FIGS. 5 to 7  show quite diagrammatically and in a viewing direction parallel to the supporting bench  18  a detailed view of the upper part of the bending-head housing  20  with different positions of the bending head  7 . 
         [0054]      FIG. 5  shows the situation before the operating position of the bending head  7  is reached, thus before the workpiece  11  is fed into the bending tool. 
         [0055]      FIG. 6  shows the situation in which the bending head  7  is in its operating position and has made a bend in the workpiece  11  (as shown in  FIG. 3 ). 
         [0056]    Finally,  FIG. 7  shows how the bending head  7  has travelled into the bending-head housing  20  into its inactive end position and the cutting device  10  has already travelled over a section of the area of the operating position of the bending head  7 . 
         [0057]    As is shown clearly by  FIGS. 5 to 7 , the workpiece  11  runs past the two blades  13 ,  14  in two grooves (not shown) each attached to the two blades  13 ,  14 , aligned relative to each other and in feed direction of the workpiece  11  and is sheared upon activation of the cutting device  10  when the movable cutting blade  14  moves relative to the stationary counter-blade  13  in the cutting plane  22 . 
         [0058]    In certain aspects of the present invention, the bending device  1  is a wire bending machine, the feeder of which continuously pulls in the workpiece  11 , namely a wire, from a coil (not shown) through the straightening units  5 . The rotatable design of the feed device  4  and the straightening devices  5  allows the wire  11  to be bent in different planes. 
         [0059]    As  FIG. 2  shows, the support arm  12  of the cutting device  10  is attached at its end area lying on the back of the bending-head housing  20  to a support  23  which for its part is movably supported on two parallel linear guides  15 . 
         [0060]    Shown between the linear guides  15 , parallel thereto, is a rack  17 , represented only quite diagrammatically in  FIG. 2 , with which a gear  24  engages, which for its part can be driven in both rotation directions via a motor  16  fastened to the support  23  and wherein the support  23  with the support arm  12  and the blades  13 ,  14  can be moved along the linear guides  15 . 
         [0061]    If the cutting device  10  is moved along the linear guides  15 , it moves on top of the bending-head housing  20 , at a slight distance therefrom, along a travel path that runs parallel to the feed direction of the wire  11 . 
         [0062]    In order to carry out the bending processes, the bending head  7  with the mandrel  8  can be moved out of the bending-head housing  20  through the opening  21  along direction b into an outer end position which is to be called the “operating position” and in which it can enter into effective engagement with the mandrel  8  in order to carry out the desired bending processes with the wire  11 . When moving out into this operating position, the wire  11  is fed into the bending tool. 
         [0063]    This deployed operating position is shown in  FIGS. 3 and 6 ; however, in each case already at a point in time after a bending process has been carried out. 
         [0064]    If several bending processes, between which the cutting device  10  is not activated, are carried out in succession, the bending head  7  can be moved out of its deployed operating position ( FIG. 6 ) into an intermediate position lying approximately vertically away from the wire  11  (direction b) as shown in  FIG. 5 : however, in this intermediate position, the top of the bending head  7  with the mandrel  8  still lies outside the bending-head housing  20  and is only so far away from the wire  11  that there is just no longer any effective engagement between the bending tool and the wire  11 . The wire  11  can then be advanced unimpeded and, as soon as a new bending process is required, the bending head  7  is returned to its operating position (in direction b) ( FIG. 6 ). 
         [0065]    However, if the bending head  7  is now no longer required during the processing of the respective workpiece  11 , but the cutting device  10  is ready for activation, the bending head  7  is retracted into the bending-head housing  20  in direction b, vertically away from the wire  11  and through the opening  21 , until it assumes its inactive end position in the retracted state. 
         [0066]    The consequence of this retraction of the bending head  7  into the bending-head housing  20  is that the bending head  7  has completely disappeared from the travel path along which the cutting device  10  can be moved in feed direction of the wire  11  at the bending-head housing  20 , with the result that the cutting device  10  can now be moved with its support arm  12  protruding as far as the wire  11  and its blades  13 ,  14  into the area of the opening  21 , even into the area occupied by the bending head  7  in its deployed operating position, without the risk of a collision of the cutting device  10  with the bending head  7 . 
         [0067]    The linear guides  15  correspondingly extend as far forward at the back of the bending-head housing  20  as a movement of the cutting device  10  downstream is desired. In the representation shown in  FIG. 2  the length of the linear guides  15  is chosen such that the cutting device  10  can be moved over the entire width of the opening  21  and thus also over the entire area of the effective engagement of the bending head  7  along its travel path if the bending head  7  is in its retracted inactive end position. 
         [0068]    Equally, the linear guides  15  could however also be made so long (not shown in the figures) that they actually extend beyond the area of the opening  21  and thus the area of the effective engagement of the bending head  7  as far as the end face of the entire machine, in order, if desired, to move the bent part produced from the wire  11  before cutting forward only as far as the end of the supporting bench  18  and to activate the drive  25  of the cutting device  10  only at the edge of the supporting bench  18 , after which the produced part can be immediately removed on the front at the bending device  1 . 
         [0069]    If the bending head  7  has been retracted into its inactive end position in the bending-head housing  20  in direction b and the cutting device  10  has then travelled over the entire open opening  21  in direction a, a situation results as shown in  FIG. 7 . In this representation the cutting plane  22  is situated only very slightly upstream of the point where, with the bending head  7  deployed into its operating position, the rotation axis  9  of the mandrel  8  would be situated. 
         [0070]    If the representations in  FIGS. 3 and 4  are compared with each other, then in  FIG. 3  the bending head  7  has made a bend of 90° (downwards in the graphic representation in  FIG. 3 ) in the wire  11  and the cutting device  10  lies immediately in front of the opening  21  of the bending-head housing  20 , i.e. only a very short distance from the bending head  7  which is in its deployed operating position. 
         [0071]      FIG. 4  shows the situation when the wire  11  provided with the bend according to  FIG. 3  is to be cut off quite close to the beginning of the bend produced. 
         [0072]    For this purpose, as shown in  FIG. 4 , the bending head  7  has been lowered through the opening  21  into its retracted, inactive end position inside the bending-head housing  20  perpendicular to the wire  11  (in direction b), after which the cutting device  10  is retracted in direction a with the two blades  13 ,  14  into the area occupied by the bending head  7  in its operating position ( FIG. 3 ), so far that the bent leg of the wire  11  has come to rest against the front face of the movable blade  14 . In this position the cutting plane  22  is situated very close to the point at which the bend made in the wire  11  begins. If the cutting process is now started, this front, bent part of the wire  11  falls onto the inclined surface of the bending-head housing  20 , from which it can drop down. 
         [0073]    If, however, during this process the cutting plane is to lie exactly at the point where the last bend of the previously bent wire  11  begins, i.e. so far as possible without a short straight piece of wire in front, then before the activation of the cutting device  10  by rotation of the feeder the bent leg of the wire  11  is swivelled upwards, with the result that it no longer lies against the front side of the movable blade  14 , lying in front. The support arm  12  can thereby be moved downstream until the cutting plane  22  established between the two blades  13 ,  14  has moved up to the beginning of the last bend of the wire  11 , after which the cutting device  10  is then activated. 
         [0074]    In order to ensure an undisturbed and continuous operation with the bending device  1  shown in the figures, the bending device  1  is connected to a machine controller (not shown in the figures) which is designed such that it allows a retraction of the cutting device  10  into the area occupied by the bending head  7  in its deployed operating position only when the bending head  7  is retracted into its inactive end position in the bending-head housing  20 , in which, as shown by the figures, in particular  FIGS. 5 to 7 , it is located wholly under the beam or support arm  12  of the cutting device  10 , with the result that in this way a collision of the cutting device  10  retracting into the operating position of the bending head  7  (or of its support arm  12  with the blades  13 ,  14 ) with the bending head  7  moved from its operating position is safely avoided. 
         [0075]    With the bending machine according to the present invention an arrangement is in principle achieved in which the bending head can be moved into an active operating position in which it protrudes into the travel path of the cutting device, and out of the latter into an inactive end position in which it is arranged completely outside the travel path, and vice versa and, as a result of this departure from the travel path, the usable travel length of the travel path is increased so that the area of the travel path into which the bending head protrudes in its operating position can then also be completely or also only partly traversed.