EP1849536B1 - Bending machine for rod-shaped workpieces like wire or tube - Google Patents

Abstract

The bending machine (10) has an auxiliary gripper (56) arranged on bending head housing, so as to be pivotable perpendicular to longitudinal axis of machine frame (16). The gripping units (52,58) are spaced apart from bending heads (54,60). The bending heads are arranged next to each other with their auxiliary grippers facing each other, and are positioned between two gripping units, such when viewed in the direction of machine frame's longitudinal axis, each bending head is mounted between other bending head and gripping unit associated with other bending head. An independent claim is included for method of bending rod-shaped workpiece made from wire or tubular material.

Description

The invention relates to a bending machine for rod-shaped workpieces made of wire or pipe material.

In the prior art different bending machines for two-sided machining of cut to length workpieces are known.

In the DE 3922326 C2 describes a bending machine with two bending heads mounted on robot arms, in which there are up to four axes of rotation for positioning the tool on the workpiece. Each of the robot arms is assigned its own guide so that it can be moved parallel to the workpiece. Between the guideways of the robot arms a gripping unit for fixing the respective workpiece to be machined is provided, which can be lowered, in which case a bending tool acts as a gripping means. The use of bending robots for bending the workpiece to be formed is very complicated, whereby even the only medium holder of the workpiece to be machined or, in its lowering, even its fixation in the bending tool can lead to the occurrence of unwanted vibrations in the longitudinal direction of the workpiece, which both the Bending accuracy as well as the possible speed of the bending operations and thus the performance of the machine adversely affected.

From the DE 4300311 C2 is a bending device with one or more movable in a plane gripping units known to transport the workpiece to be machined between mutually parallel bending stations, each of which performs a single bending operation. During bending itself, the tool is fixed by the jaws of the bending tool of the respective bending station. The bending heads sit on a vertically movable table to allow transport of the workpieces without vertical movement of the gripping units. This known machine is very complex in its overall construction and also does not allow processing of wire directly from the coil.

The DE 19630023 A1 describes a bending machine with several bending stations, in which a workpiece can be processed either on one side and then on the other side or, in the case of bends in one plane, from both sides at the same time. In this case, a plurality of gripping units are provided for conveying the workpiece between the individual bending stations, wherein the grippers are also used for rotating the workpieces. The bending heads are arranged movable parallel to the workpiece axis. All gripping units are attached to a portal. This known bending machine is built very expensive, which applies in particular to the arrangement of the gripping devices on a portal construction. Even with this known bending machine processing of directly deducted from the coil wire is not possible.

Also from the DE 20 2004 011 947 U1 known bending machine is used to edit elongated workpieces in several stations. In this case, each station has a central gripping unit and two bending heads mounted laterally thereof, which, like the gripping unit, can be moved on a common guide bed. In addition, a pivotable transfer device is provided with which the workpiece can be pivoted from the first processing station into the second, parallel processing station. The transfer device can also be the gripping unit at the same time. This known machine works serially out of a magazine and also does not allow processing of wire directly from the coil.

Proceeding from this, the present invention seeks to propose a new bending machine of the type mentioned, which is also suitable for processing wire from the coil, has a relatively simple structure, is particularly flexible and high unit performance allowed.

According to the invention this object is achieved by a bending machine for rod-shaped workpieces made of wire or pipe material, wherein on a machine frame on both sides of a frame longitudinal axis of the same each at least one bending station is provided with two bending units, each having a bending head with a bending head housing and a bending tool and a on the bending head housing perpendicular to the longitudinal axis of the frame pivotally mounted auxiliary gripper and an associated, seen in frame longitudinal axis offset at a distance from the bending head mounted, perpendicular to the frame longitudinal axis pivoting and movable in the direction thereof on a guide gripping device, further wherein each bending unit the two bending heads next to each other and with their auxiliary grippers facing each other and are arranged between the two gripping means that each bending head - seen in the direction of the frame longitudinal axis - between the other bending head and the associated gripping device is attached.

The bending machine according to the invention is very flexible because it not only allows the machining of rod-shaped workpieces out of a magazine, but also allows the processing of material from the coil. The arrangement of one bending station with two bending units on both sides of the longitudinal axis of the frame of the bending machine according to the invention makes it possible to successively bend both ends or sides of a cut workpiece into a desired shape in a bending station. By arranging at least two bending stations (ie one on each side of the machine frame) with pairs mounted bending heads with belonging gripping device, it is possible to edit at least four workpieces in different stations at the same time, which represents a significant increase in performance, each cut workpiece alternately in the first and then in the second bending unit of the respective bending station is processed. Since each bending unit fixes the workpiece in question itself, after machining a workpiece in a first bending device and transferring it to the second bending device of the same bending station in the first bending device then simultaneously and parallel to the processing of the dispensed workpiece in the other bending station again a new workpiece be recorded and edited.

Characterized in that the gripping means of each bending unit perpendicular to the longitudinal axis of the frame take the workpieces in an alignment parallel to this, is a central feed of the workpieces in frame longitudinal direction (with alignment in this) between the arranged on both sides of the machine frame bending stations possible. As a result, the drawing, straightening and separating the wire from the coil can be carried out by an upstream unit, wherein after the cutting, the cut workpiece is present in a position suitable for gripping between the bending stations.

However, you can operate the bending machine according to the invention without such a feed and straightening unit and cutting device, in which case already cut to length workpieces in a magazine, such as the side of the machine frame, must be provided. The arrangement of the bending stations with their bending units can be in the bending machine according to the invention without any problems and a seizure of individually provided workpieces from the magazine and their transfer to the relevant bending unit without difficulty.

Similarly, it is also possible that z. B. workpieces a shaping on one side of the bending machine in the local bending station and workpieces with a different shape (also about a different length) are made in the bending station on the other side of the frame, so that a simultaneous processing of different workpieces with the bending machine according to the invention is possible.

A further increase in the flexibility of the use of the bending machine according to the invention can also be achieved if two or even more bending stations are arranged on each side of the frame longitudinal axis, in which case on all bending stations of the respective bending machine z. B. the same workpieces can be edited to further increase the unit performance of the machine. However, it would also be conceivable that in each bending station of such a bending machine a workpiece to be shaped differently is bent, so that even the simultaneous bending of a plurality of different workpieces could take place.

In the bending machine according to the invention, of course, a separate guide can be attached to each of the two gripping devices of a bending station. However, it is particularly preferred if both gripping devices of a bending station can be moved along the same guide.

The guidance of the gripping devices can be formed in any suitable manner. However, each guide for the gripping means of a bending station particularly preferably consists of two guideways parallel to one another and to the frame longitudinal axis, in particular in the form of guide rails, on the machine frame. If more than one bending station is provided on each side of the machine frame in a bending machine according to the invention, it is particularly preferred if all gripping devices of all bending stations on the same side of the bending machine can be moved along the same guide rails on the machine frame. As a result, not only a simplification of the overall structure, but in particular a precise alignment of the adjustment directions of the gripping means of a bending station can be achieved relative to each other.

Advantageously, in a bending machine according to the invention, each auxiliary gripper comprises a support arm, which is mounted pivotably on the side of the bending head housing of the associated bending head, wherein, again preferred, this support arm at its projecting end a movable radially to its pivot axis, with two gripping jaws for gripping the bending tool Having provided to be supplied bar-shaped workpiece gripping assembly. This results in a relatively simple construction, but very effective overall design arrangement for the auxiliary gripper.

It is furthermore advantageous if, in the bending machine according to the invention, each gripping device likewise comprises a pivotable lever arm which, at its end region facing away from its pivot axis, carries a gripping arm pivotably mounted around another pivot axis, which gripper arm offset two at a distance in the longitudinal direction of the frame longitudinal axis Has gripping arrangements for gripping a rod-shaped workpiece. Preferably, the pivot axes of the lever arm and the gripping arm of each gripping device lie parallel to one another. This also results in a relatively simple structure for the individual gripping device.

Each gripping device is preferably accommodated with its associated drives on a holding plate, which in turn sits movably on the guide rails on the machine frame.

A further preferred embodiment of the bending machine according to the invention also consists in that each bending head housing is fixedly attached to the machine frame, however, wherein the bending tool is movable in the direction of its axis of rotation relative to the bending head housing.

Advantageously, the machine frame is provided in a bending machine according to the invention in its upper portion to which the bending stations are mounted with a cross-section substantially isosceles trapezoidal machine bed, wherein the bending stations arranged on both sides of the frame longitudinal axis respectively at the obliquely extending there side of the machine bed are. As a result, a very particularly advantageous overall arrangement is achieved, which is also relatively space-saving while allowing easy and unobstructed access to the individual elements of the bending stations.

The method of holding plates with the gripping means seated thereon along the guide rails can be done in any suitable manner. However, it is particularly preferred if the gripping devices are each movable over a rack drive along the guides, in which case over the entire length of the guides on a rack side away the use of a single rack for moving all holding plates with gripping devices sufficient.

In addition, it is particularly favorable if, in the bending machine according to the invention, both the bending heads with the auxiliary grippers have an identical construction to each other, as also the gripping device in a bending station to each other.

It is equally advantageous if in each case two bending stations, which are opposite one another with respect to the frame longitudinal axis, are of mutually identical construction.

Fig. 1

eine perspektivische Ansicht (von schräg vorne oben) auf eine erfindungsgemäße Biegemaschine mit vorgeschalteter Vorschub- und Richteinheit sowie mit Schneid- und Führungseinheiten;

Fig. 2

eine Draufsicht auf die Biegemaschine aus Fig. 1;

Fig. 3

eine Endansicht einer Biegemaschine nach Fig. 1 von deren (in Maschinen-Längsrichtung gesehen) Endseite her;

Fig. 4

eine perspektivische Draufsicht auf eine Biegestation der Biegemaschine aus Fig. 1;

Fig. 5

eine vergrößerte Perspektivansicht einer auf einer Halteplatte montierten Greifeinrichtung der Biegemaschine aus Fig. 1, und

Fig. 6

eine perspektivische (vergrößerte) Detaildarstellung eines Biegekopfes mit Biegekopfgehäuse und an diesem verschwenkbarem Hilfsgreifer der Maschine aus Fig. 1.

The invention will now be explained in more detail by way of example with reference to the drawings in principle. Show it:

Fig. 1

a perspective view (obliquely from the top front) on a bending machine according to the invention with upstream feed and straightening unit and with cutting and guiding units;

Fig. 2

a plan view of the bending machine Fig. 1 ;

Fig. 3

an end view of a bending machine after Fig. 1 from the end side (seen in the machine longitudinal direction);

Fig. 4

a perspective top view of a bending station of the bending machine Fig. 1 ;

Fig. 5

an enlarged perspective view of a mounted on a holding plate gripping device of the bending machine Fig. 1 , and

Fig. 6

a perspective (enlarged) detail of a bending head with bending head housing and on this pivotable auxiliary gripper of the machine Fig. 1 ,

In Fig. 1 a bending machine 10 for processing wire 12 from the coil is shown. The bending machine 10 is provided on the input side with a feed and straightening unit 14, which is followed by a machine frame 16, which has a cross-sectionally substantially isosceles trapezoidal machine bed 18 in its upper region, as shown in the (only in principle indicated) representation of the machine frame 16 in the end view of the bending machine 10 in FIG Fig. 3 is clearly recognizable in detail.

The bending machine 10 has a frame longitudinal axis MM , wherein on the machine bed 18 on both sides of the frame longitudinal axis MM, opposite each other, a first bending station 20 (in the illustration of Fig. 1 : lying on the front) and a second bending station 22 (in the representation of Fig. 1 : lying on the back) are attached.

First, reference is made to the feed and straightening unit 14, which has at least one feeder module 24 with a feed roller pair 26 for drawing in the wire 12 from a coil (not shown). In addition, a straightening module 28 is further provided, which may consist of a conventional rotating straightening body or from a straightening apparatus with rollers and the wire 12 is directed by bending in all planes straight.

The straightening module 28, a further feed module 30 with a pair of feed rollers 32 and a length measuring device 34 are connected downstream, the latter can be brought to determine the exact feed length with the wire 12 in engagement.

Behind the advancing and straightening unit 14 of the wire 12 passes through a cutting and guiding unit 36, wherein it is supported over its entire length by a plurality of frame longitudinal direction on the machine bed 18 at a distance from each other arranged guide elements 38.

At a suitable location between these guide elements, namely in the illustrated bending machine 10 (seen in the conveying direction R of the wire 12) after the second guide member 38 behind the exit point of the wire 12 from the feed and straightening unit 14, is a cutting module 40 on the machine bed 18th mounted so that it separates the wire 12 after a corresponding feed length and thus produces a cut, elongated workpiece 42 as the starting workpiece for the subsequent bending operations. In this case, the position of the cutting module 40 is suitably selected at a location which lies between the bending stations 20 and 22 before the entry of the cut workpiece 42, that there directly after the cutting process and without further transport in the frame longitudinal direction of a gripping device of a downstream Bending device of a bending station 20 or 22 well detected and then transferred to one of the bending stations 20 and 22, respectively.

At the bending machine 10 off Fig. 1 the first bending station 20 and the second bending station 22 are formed with an identical structure, for which reason only the first bending station 20 (namely the in Fig. 1 front, ie, the viewer facing bending station) to be described in more detail, as their description applies in the same way to the second bending station 22.

The first bending station 20 has two bending units 44 and 46 and the opposite second bending station 22 two bending units 48 and 50 on.

The first bending unit 44 of the bending station 20 comprises a gripping device 52 and a bending head device 54 with an auxiliary gripper 56 mounted thereon and pivotable in a plane perpendicular to the frame longitudinal axis MM .

The other bending unit 46 of the bending station 20, in turn, likewise comprises a gripping device 58, a bending head device 60 and an auxiliary gripper 62 mounted thereon and pivotable in a plane perpendicular to the frame longitudinal axis MM .

Each of the two gripping devices 52 and 58 is seated on a holding plate 64 and 66, respectively. Both holding plates 64, 66 are mounted on a guide extending in the longitudinal direction MM on the machine bed 18 (in the direction Z in FIG Fig. 1 and Fig. 6 ) traversable, with this guide off two parallel to each other and to the frame longitudinal axis MM guideways in the form of correspondingly formed guide rails 68, 70 consists.

The displacement of the holding plates 64, 66 takes place along the guide rails 68, 70 via a rack 72 motor and parallel to the cut workpiece 42.

The two bending heads 54 and 60, their structure in detail in an enlarged view in Fig. 6 is shown (which will be discussed in more detail below) are in turn fixedly mounted on the guide rail pair 68, 70 and not displaceable relative to these. Only the two auxiliary grippers 56 and 62 are, like this Fig. 6 shows in detail, laterally mounted on the bending head housing 84 pivotally mounted (in the pivoting direction T in a pivoting plane perpendicular to the frame longitudinal axis MM) .

The gripping device 52 on the holding plate 64 cooperates with the bending head device 54 and the laterally associated auxiliary gripper 56 in the context of the first bending unit 44, while the other gripping device 58 with the bending head device 60 with the laterally attached auxiliary gripper 62 in the context of the second bending unit 46th cooperates.

The same applies to the second bending station 22 arranged opposite the first bending station 20 and the bending units 48 and 50 included therein.

From the top view of the bending machine 10 off Fig. 1 as they are in Fig. 2 is shown once again is good on both sides of the frame longitudinal axis MM (which coincides in plan view with the orientation of the supplied wire 12) arrangement of the bending stations 20 and 22 and their respective two bending units 44, 46 (bending station 20) and 48, 50 (bending station 22) removable.

From the representation of Fig. 1 and 3 the latter taking a look at the bending machine 10 from its end side (in Fig. 1 Thus: from the right-most end), it can be seen that the bending stations 20 and 22, relative to the vertical longitudinal center plane of the machine frame 16, a mirror-symmetrical arrangement of the individual elements of both bending stations 20, 22 to each other.

First, however, reference is made to the representation of Fig. 5 in an enlarged perspective view of the structure of a gripping device, namely the gripping device 58 from Fig. 1 , represents.

The gripping device 58 comprises a lever arm 74 which is pivotable about a rotational axis D parallel to the direction of movement Z in the direction of rotation Y. The pivoting movement is effected by a motor 76, to which the lever arm 74 is connected.

At its end region remote from the axis of rotation D, a gripping arm 78 is pivotably mounted in the direction of rotation X on the lever arm 74 about an axis of rotation E parallel to the axis of rotation D of the lever arm 74. The likewise extending in the direction of the axis of rotation E gripper arm 78 has on its underside two at a distance a from each other remote gripping assemblies 80, each of two arranged perpendicular to the rotation axis E , mutually movable gripping jaws 82 for gripping the workpiece 42 includes, as Fig. 5 shows in detail what is being referred to.

The gripping device 58 is seated on a retaining plate 66, which also receives the motor 76 and other required for the operation of the various movements drives.

By pivoting the lever arm 74 in the direction of rotation Y , the gripping device 58 can be pivoted toward the centrally delivered between the two bending stations 20 and 22 workpiece 42 to take this with the gripper arm 78 by means of the two gripping assemblies 80, after which it by pivoting in Counter direction in the region of the bending station 20 for performing bending operations can be converted there.

Equally, however, could also be in the bending station 20 already partially bent workpiece 42 with the gripping device 58 after the bending operations either by further pivoting laterally deposited from the machine frame 16 or, for pivoting in the opposite direction z. B. passed to the opposite bending station 22, where it is received by a gripping device of this bending station and then subjected to further bending shapes.

The entirety of gripping device 58 with holding plate 66 thus has two axes of rotation D and E and is movable in the direction Z. For special applications, but it might also be appropriate to form the gripping device 58 so that the gripping arm 78 in turn also about a through the axes of rotation D and E extending and perpendicular to these axes of rotation further (third) axis of rotation is rotatable. This creates the possibility of picking up a workpiece 42 even in a starting position or output in an orientation that is not aligned parallel to the frame longitudinal axis MM .

Reference should now be made to the illustration of Fig. 6 , in an enlarged perspective oblique view (obliquely from the top front) the structure of a Biegekopfeinrichtung with associated auxiliary gripper, here the bending head device 60 and the auxiliary gripper 62, with the gripping device Fig. 6 cooperate within the first bending unit 44 of the first bending station 20 shows. The bending head device 60 comprises a bending head housing 84, on which a bending tool 86 is mounted, which consists of a central, in turn rotating in the direction of rotation U bending mandrel 88 and an associated, arranged concentrically to him in the direction of rotation V rotatable bending pin 90.

On the bending head housing 84, immediately laterally to this, in a direction of rotation T about a pivot axis F pivotable auxiliary gripper 62 is attached, which consists of a support arm 92, at the end facing away from its pivot axis F a gripping assembly 94 is provided with two mutually movable gripping jaws 96. The gripping assembly 94 with the gripping jaws 96 is in the direction S (ie in the longitudinal direction of the support arm 92) radially displaceable to the pivot axis F. The pivot axis F of the support arm 92 extends parallel to the frame longitudinal axis MM and sits at a position on the side of the bending head housing 84 so that when the support arm 92 is aligned parallel to the axis of rotation of the bending tool 86 (bending mandrel 88 and bending pin 90) between the Gripping jaws 96 held to be machined workpiece 42 has a proper for the recording by the bending tool 86 alignment.

Fig. 4 FIG. 3 illustrates an oblique perspective view of a portion of the bending machine 10 which essentially comprises the bending station 20. Here are in Fig. 4 only the essential structural parts shown and all omitted for the representation of the relative positions of these parts to each other unimportant details of the machine.

Fig. 4 FIG. 12 shows the state of the machine in which the requested wire has just been cut by the cutting module 40 (the wire lying in the feeding direction in front of the cutting module 40 is omitted), resulting in a cut workpiece 42 (here: a wire section of a predetermined length) initially held by various longitudinally offset guide members 38.

The gripping device 58 has now been pivoted so that the gripping jaws 82 on the underside of the gripping arm 78 grasp the elongate workpiece 42 at its front end region at two mutually offset locations and then transfer it by pivoting in the direction Y in the working range of the bending station 20 , If necessary or desired, also the auxiliary gripper 62 of the cooperating with the gripping device 58 Biegekopfeinrichtung 60 can also in the direction of the workpiece 42nd pivoted, this also detected by the jaws 96 of this auxiliary gripper 62 at a further point and then transferred together with the gripping device 58 in the bending station 20 by pivoting back.

How out Fig. 4 Also clearly visible, the bending heads 54 and 60 of the first bending station 20, both of which are fixedly mounted on the guide rails 68, 70 of the machine bed 18, are aligned differently, so that there are inclined bending axes of their bending tools.

The bending machine 10 shown in the figures operates in the manner set forth below, illustrated by means of a continuously fed wire 12:

As Fig. 1 shows, the wire 12 is withdrawn from a coil (not shown) through the feed module 24 via the feed rollers 26 and fed to the straightening module 28. The arranged behind this further feed module 30 pulls the straightened wire 12 out of the straightening module 28 and promotes him on the other feed roller pair 32 of the downstream length measuring device 34. From the length measuring device 34 of the wire 12 is further promoted in the separating and guiding unit 36. As soon as the desired length of wire has been detected by the length measuring device 34, the feed modules 24 and 30 are stopped, the cutting module 40 is actuated and thus a cut workpiece 42 is produced, as is known Fig. 4 is apparent.

The first cut workpiece 42 is now machined in the first bending station 20. By moving the holding plate 66 of the gripping device 58 in the Z- direction and by pivoting the lever arm 74 and the gripping arm 78 about their respective pivot axis D and E , the gripping arrangements 80 on the gripper arm 78 in the path of the cut-to-length workpiece 42 mounted on the guide elements 38 (FIGS. see. Fig. 4 ) and the workpiece 42 are gripped at its end region there (see. Fig. 4 ). If it is a long workpiece to be machined 42, as already described above, the cooperating with the gripping device 58 auxiliary gripper 62 can be pivoted to the bending head device 60 to the workpiece 42 and this also grasp with his gripping jaws 96 to prevent that z. B. the workpiece 42 begins to swing during the return pivoting to the bending head device 60 of the bending unit 46.

The gripping device 58 and the auxiliary gripper 62 then pivot the workpiece 42 into the area of the bending head device 60.

As a result of the movements of the bending tools in the directions U, V and W and by the movement of the holding plate 66 in the Z direction and the gripping device 58 about the pivot axes D and E , the cut workpiece 42 can be provided on one side with bends in different planes ,

In order to be able to machine the workpiece 42 on its other side, the gripping device 52 and the auxiliary gripper 56 of the other bending unit 44 then pivot toward the bending head device 60 and pick up the pre-bent workpiece 42, after which they pivot it to the bending head device 54. There, the second portion of the workpiece 42 is then bent and then the finished bent workpiece 42 by the gripping device 52 laterally of the bending machine 10, z. B. on a conveyor belt or the like, are stored.

After the workpiece 42 has been transferred from the bending unit 46 to the other bending unit 44, the bending unit 46, a new workpiece 42 are supplied.

During processing of a workpiece 42 in the bending unit 46, the feed modules 24 and 30 are actuated again and a second, cut workpiece 42 is produced. This is then processed in the opposite second bending station 22, to which the picking device arranged there relative to the gripping device 58 picks up this second workpiece 42 and pivots it into the bending region of the bending head device 60 opposite bending head device.

The feed and straightening unit 14 now supplies alternately the first bending station 20 (front) and the second bending station 22 (rear), wherein in both bending stations the workpiece 42 respectively first in the bending unit 46 and 50 and then in the bending unit 44 and 48, respectively is bent.

Due to their construction, the bending machine 10 is extremely flexible:

Thus, the same workpieces can be bent in the bending stations 20, 22, which can be achieved almost twice the unit performance compared to a simple machine. Likewise, in both bending stations 20, 22 also different parts can be produced on both sides of the machine, even from different lengths wire sections.

The bending machine 10 can be operated without the feed and straightening unit 14 when z. For example, cut-to-length workpieces can be provided in a magazine. The processing would in this case run in series and the respective workpiece 42 in up to four processing stations (bending units) transformed. A transfer from the first bending station 20 in the second bending station 22 is possible with the gripping means 52 and 58 without difficulty.

It is also possible to arrange several bending stations on each side of the bending machine 10 in succession, so that more than four bending units are realized on each side. The gripping device 58 is designed so that the transfer to another, adjacent to the bending machine 10 bending machine (not shown in the figures) could take place.

All processes of the overall machine are controlled in the usual way by a central (not shown in the figures) program control.

The gripping arms of all gripping devices 52, 58, etc. are preferably pivotable through 360 °, while the lever arms of the gripping means 52, 58, etc., as well as the support arms of the auxiliary gripper 56, 62, etc. are pivotable through 180 °.

The bending head housing 84, etc. of the individual bending head devices 60, etc. include the drive for the bending pins, the drive for the bending mandrels and the drive for the mobility of the actual bending head (bending tool) in the direction W.

Claims (17)

1. Bending machine (10) for rod-shaped workpieces (42) of wire or tube material in which is provided, on both sides of a longitudinal frame axis (M-M) of a machine frame (16), at least one bending station (20, 22) having in each case two bending units (44, 46; 48, 50) each one of which comprises a bending head (54, 60) with a bending head housing (84) and a bending tool (86), an auxiliary gripper (56, 62) attached to the bending head housing (84) so as to be pivotable perpendicular to longitudinal frame axis (M-M) and an associated gripper device (52, 58) offset at a distance from the bending head (54, 60) when looked at along the longitudinal frame axis (M-M) said gripper device being pivotable perpendicular to the longitudinal frame axis (M-M) and movable in the direction of said axis on a guide (68, 70),
   whereby additionally in each bending unit (44, 46; 48, 50) the two bending heads (54, 60) are disposed next to each other and facing each other with their auxiliary grippers (56, 62) as well as being disposed between the two gripper devices (52, 58) such that each bending head (54, 60) - seen in the direction of the longitudinal frame axis (M-M) - is attached between the other bending head (60, 54) and the gripper device (58, 52) associated with it.
2. Bending machine according to claim 1, in which both gripper devices (52, 58) of a bending station (20, 22) are movable longitudinally along the same guide (68, 70).
3. Bending machine according to claim 1 or 2, in which each guide for the gripper devices (52, 58) of a bending station (20, 22) consists of two guide rails (68, 70) on the machine frame (16) which are parallel to each other and also to the longitudinal frame axis (M-M).
4. Bending machine according to one of claims 1 to 3, in which each auxiliary gripper (62) comprises a support arm (92) which is pivotably supported directly on the side on the bending head housing (84) of the associated bending head (60).
5. Bending machine according to claim 4, in which the support arm (92) has on its projecting end a gripper arrangement (94) movable radially to its pivot axis (F) provided with two gripper jaws (96) for grasping the rod-shaped workpiece (42) to be fed to the bending tool (86) for bending.
6. Bending machine according to one of claims 1 to 5, in which one bending station (20, 22) is provided in each case on both sides of the longitudinal frame axis (M-M).
7. Bending machine according to one of claims 1 to 6, in which each gripper device (52, 58) comprises a pivotable lever arm (74), which carries on its end region facing away from its pivot axis (D) a gripper arm (78) pivotable for its part about a further pivot axis (E), said gripper arm having two gripper arrangements (80) offset from each other at a distance (a) in the longitudinal direction of the longitudinal frame axis (M-M) for grasping a rod-shaped workpiece (42).
8. Bending machine according to claim 7, in which the pivot axes (D, E) of the lever arm (74) and of gripper arm (78) of each gripper device (52, 58) lie parallel to each other.
9. Bending machine according to one of claims 1 to 8, in which each gripper device (52, 58) is accommodated with its associated drives (76) on a retaining plate (64, 66) which for its part sits movably on the guide (68, 70) on the machine frame (16).
10. Bending machine according to one of claims 1 to 9, in which upstream of the machine frame (16), are connected a feed and straightening (14) unit, by means of which a wire (12) or a tube may be fed centrally between the two bending stations (20, 22) and parallel to the longitudinal frame axis (M-M), and a cutting unit (40) for cutting off the wire (12) or the tube, which is fed in, at a point before it enters between the bending stations 20, 22).
11. Bending machine according to one of claims 1 to 9, with an associated magazine for rod-shaped workpieces (42) from which said individual rod-shaped workpieces (42) are removable by the gripper device (58) and the auxiliary gripper (62) of a lateral bending unit (46) for processing on the bending machine (10).
12. Bending machine according to one of claims 1 to 11, in which each bending head housing (84) is fixedly attached to the machine frame (16) whereby, however, the bending tool (86) is movable in the direction of its rotational axis relative to said bending head housing (84).
13. Bending machine according to one of claims 1 to 12, in which the machine frame (16) in its upper section, on which the bending stations (20, 22) are provided, has a machine bed (18), which in cross-section is shaped substantially like an equilateral trapezium, whereby the bending stations (20, 22) on both sides of the longitudinal frame axis (M-M) are each attached on the sloping side of the machine bed (18).
14. Bending machine according to one of claims 1 to 13, in which the gripper devices (52, 58) are each movable along the guides (68, 70) by way of a rack-and-pinion drive (72).
15. Bending machine according to one of claims 1 to 14, in which both the bending heads (54, 60) with the auxiliary grippers (56, 62) and also the gripper devices (52, 58) of a bending station (20, 22) each have an identical construction to one another.
16. Bending machine according to one of claims 1 to 15, in which in each case two bending stations (20, 22) opposing each other in relation to the longitudinal frame axis (M-M) have an identical construction.
17. Bending station according to one of claims 1 to 16, in which two or more bending stations (20, 22) are provided on each side of the longitudinal frame axis (M-M).

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