DE20212241U1 - Device for bending hollow profile bars - Google Patents

Description

pOlta Patent attorneys

Dipl.Phys. Ulrich Twelmeier Dr. techn. Waldemar Leitner Dr. phi/, not. Rudolf Bauer-1990 Dipl.lng. Helmut Hubbuch -1991 European Patent Attorneys

LE01E043DEU/hl02s047/hl/TW/02.08.2002

Lenhardt Maschinenbau GmbH,

Karl-Lenhardt-Strasse 1-9, D-75242 Neuhausen-Hamberg

Device for bending hollow profile bars

Description:

The invention is based on a device with the features specified in the preamble of claim 1. Such a device is known from EP 0 483 044 A1. The known device is used for bending hollow profile bars to form spacer frames for insulating glass panes. The hollow profile bars have two parallel flanks as well as an inner wall and an outer wall which connect the flanks to one another. In particular, it concerns so-called box profiles which are to be bent as long as the hollow profile bars do not yet contain a granular drying agent which spacer frames in insulating glass panes must contain. The device has a frame which carries a bending tool. The bending tool has a bending beam which can be pivoted about a pivot axis and acts on the outer wall of the hollow profile bar for bending. The bending tool also includes a

Zerrennerstrasse 23-25 D-7$lPforzheim'. '. \ ' '. "·'.'· ' .'··.;. PoitbanßKdr/snJhe 16852-750 (BLZ66010075) Telefon(07231)39840 Tetefa«}0723U&JjM:'.. .'...'... .'... '. Spurkash Pforzheim 803 812 (BLZ66650085) Our general terms and conditions apply exclusively VAT Registration No. DE 144 180005

Bending abutment around which the hollow profile bar is bent, and a support which is arranged on the side of the pivot axis of the bending beam facing away from the starting position of the bending beam and which supports the outer wall of the hollow profile bar so that its leg lying on the relevant side of the bending abutment cannot move while the leg lying on the other side of the bending abutment is bent. The bending abutment is intended to mark the point at which the hollow profile bar is bent, press in the inner wall of the hollow profile bar and cause the hollow profile bar to assume a predetermined shape on its inner wall at the bending point.

The bending abutment known from EP 0 483 044 A2 consists of two abutment parts, each of which has the shape of a rivet. The two abutment parts are arranged coaxially so that their two heads face each other. Their mutual distance can be changed in order to be able to adjust them to hollow profile bars of different widths. For this purpose, one abutment part is attached to a stationary guide jaw and the other abutment part is attached to a movable guide jaw, which is parallel to the stationary guide jaw and opposite it and whose distance from the stationary guide jaw can be changed. These guide jaws serve on the one hand to guide the hollow profile bar while it is fed to the bending tool and on the other hand to prevent the flanks of the hollow profile bar from bulging during bending.

The disadvantage of the known bending device is that a distance is required between the bending abutment on the one hand and the alignment lines defined jointly by the support and the bending beam in their initial position on the other hand, which is significantly greater than the height of the hollow profile bar; this is necessary in order to be able to insert the hollow profile bar unhindered into the bending tool, push it forward after bending and finally remove it again. The disadvantageous consequence of this is that the hollow profile bar cannot

is well guided and that the bending beam must first lift the hollow profile bar against the bending abutment before bending, which is detrimental to the quality and repeatability of the bending result.

The proposal for a bending device known from EP 0 771 597 B1 aims to avoid these disadvantages, in which the two-part bending abutment is adjustable separately from the guide jaws. However, this proposal requires a complex and heavy mechanism with several pressure cylinders in order to be able to move the bending abutment independently of the guide jaws.

The object of the present invention is to create a device which is simpler than that of EP 0 771 597 B1 and which, on the one hand, makes it possible to better guide the hollow profile rod up to the start of the bending process and during the bending process and, after the bending process, to release it to such an extent that it can be pushed forward through the bending tool and finally removed from the device.

This object is achieved by a device having the features specified in claim 1. Advantageous developments of the invention are the subject of the subclaims.

The invention solves the problem by a special design of the two-part bending abutment, in that it can be pivoted by means of its own drive about the pivot axis of the bending beam or about an axis adjacent to it and parallel to it, but preferably about the pivot axis of the bending beam, and that the two abutment parts have an eccentric shape with respect to their pivot axis in such a way that the bending abutment is at a distance from the plane in which the bending beam and the support are aligned with each other (this is also the conveyor track on which the hollow profile bars move with their outside during the feed) at the beginning of the bending process,

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which is equal to or smaller than the height of the hollow profile bar, after the bending process, during which the bending abutment is also pivoted, but has a distance which is greater than the height of the hollow profile strip. In order to maintain this greater distance when the hollow profile bar is pushed forward, the bending abutment can be pivoted independently of the bending beam, so that after the bending process, when the bending beam is moved back to its starting position, it can remain in its deflected position or can be pivoted further into an end position in which the hollow profile bar can be pushed forward over the bending beam to the next bending point without hindrance and without touching the bending abutment. Only then is the bending abutment pivoted back into its starting position, in which it rests against the inner wall of the hollow profile bar and preferably presses this in slightly before the bending process begins, thus clearly marking the bending point.

The invention uses extremely simple means to ensure that the bending abutment fully fulfils its abutment function during the bending process, but is ineffective when the hollow profile bars are pushed forward. The inner wall of the hollow profile bar, which is the only wall that is later clearly visible in the insulating glass pane, remains free of scratches and other grinding marks, which are particularly annoying when the surface of the hollow profile bar is shiny or painted.

In order to be able to move the bending abutment separately from the bending beam for the purposes of the invention, a simple pneumatic cylinder is sufficient. This can be controlled in such a way that at the beginning and during the bending process it presses the bending abutment against the hollow profile bar and thus against the bending beam, whereby the hollow profile bar is clamped between the bending abutment and the bending beam and the bending beam carries out the bending process while overcoming the counterforce exerted by the pneumatic cylinder. Once the desired bending angle has been reached and the bending beam is then returned to its starting position

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swung back, the pressure cylinder can be depressurized or, better still, reversed so that it is swung further to an end position in which it no longer touches the hollow profile rod during advance. After the hollow profile rod has reached its next bending point, the bending abutment is swung back to its starting position by actuating the compressed air cylinder. In this context, it is particularly preferred if the bending abutment or one of its parts is arranged at the tip of a counterholder opposite the bending cheek, which is designed to rest against the inner wall of the hollow profile rod. Such a counterholder not only makes the counterholder easier to handle, but can also form a clamp together with the bending cheek in which the hollow profile rod can be temporarily secured as required. For this purpose, the surface of the counterholder facing the inner wall of the hollow profile rod is preferably flat.

A possibility of clamping the hollow profile bars is preferably also provided on the opposite side of the pivot axis, in the vicinity of the support, where preferably a rear clamping jaw and a front clamping jaw are provided, which are intended for clamping the flanks of the hollow profile bar, whereby the rear clamping jaw should be stationary and the front clamping jaw should be movable. The rear clamping jaw limits the pivoting movement of the bending beam. In order to achieve large pivoting angles, it is preferably provided that the rear clamping jaw and the counterholder are wedge-shaped, whereby the wedge tip points towards the bending abutment and the wedge surfaces are arranged and designed in such a way that the wedge surface of the counterholder finally strikes the rear clamping jaws when the counterholder is pivoted and finds its end position there, whereby the stop is preferably flat. The wedge angles of the counterholder and the rear clamping jaw should be selected so that they are together less than 50°, in particular less than 30°, so that correspondingly large bending angles, which far exceed 90°, are possible.

Two types of hollow profile bars are commonly used to produce spacer frames for insulating glass panes. The most commonly used are so-called box profiles, in which the inner wall extends at right angles from parallel flanks of the hollow profile bar and the outer wall runs parallel to the inner wall in a central area and is connected to the flanks on both sides via inclined surfaces. The terms "inside" and "outside" are derived from the finished bent spacer frame: the inner wall points into the interior of the insulating glass pane; the outer wall points in the opposite direction. In the other type, which is also commonly used, the parallel flanks protrude beyond the inner wall, whereby the distance between the inner wall and the outer wall is generally smaller than with box profiles. This type of profile, in which the flanks protrude beyond the inner wall, is also known as a web profile. Web profiles have the advantage over box profiles that their inner wall does not have to be deformed as much when bent because it is closer to the "neutral phase". Web profiles are usually bent after they have been filled with a granular desiccant, which the spacer frames must contain before they are installed in the insulating glass pane. The invention is particularly suitable for bending hollow profile bars that are still empty, especially for those with box profiles. When bending box profiles, a bending abutment has proven to be useful in which the abutment parts have a predominantly cylindrical surface with a radius of 2 mm to 3 mm, in particular 2.5 mm, in a first circumferential section.

In order for the bending abutment to act only on the inner wall and not on the flanks of the hollow profile bar during bending, it must be adapted to the width of the hollow profile bars so that its width is at least twice the wall thickness of the hollow profile bars smaller than the width of the hollow profile bars. To achieve this, the distance between the two bending abutment parts can be changed, whereby the rear bending abutment part is not arranged so that it can be moved, but rather is in line with the rear clamping jaw, which is located in the vicinity of the support. The front abutment part, on the other hand, is in

Direction of the pivot axis can be adjusted, ideally by coupling it to a clamping jaw that can be placed on the front flank of the hollow profile bar, so that no separate drive is required to adjust the front bending abutment part. It is best to couple the abutment detachably to a separate clamping device which is arranged in the immediate area of the pivot axis and acts on the flanks of the hollow profile bar there. Such a separate clamping device in the area of the pivot axis is particularly useful because it can prevent the flanks from bulging in the immediate corner area of the hollow profile bar to be bent, at a point where the tendency for bulging is greatest. This separate clamping device, or at least the jaws which move the clamp, can preferably be pivoted with the bending abutment or with the bending cheek in order to keep the friction between the jaws and the flanks of the hollow profile bar as low as possible during the bending process.

The pivotability of the rear jaw, which is coupled to the bending abutment, is most easily achieved by taking it along with the bending abutment or the counterholder on which the bending abutment is located when pivoting. The associated front jaw and the front abutment part coupled to it can also be taken along with the rear abutment part or the counterholder by connecting them with a driver.

A particularly suitable eccentric shape for the abutment parts is one in which a first circumferential section is cylindrical and a second circumferential section is flat, in particular planar or even concave, wherein the extent to which the hollow profile bars can be released by pivoting the bending abutment is particularly large if both circumferential sections lie on one and the same side of the pivot axis.

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Preferably, the bending abutment and the counterholder are attached to a pivoting support in an exchangeable manner so that they can be replaced in the event of wear or in the case of bending tasks for which a different bending abutment is more suitable. One such other application would be, for example, the bending of web profiles already filled with granular desiccant, for which an undivided bending abutment is more suitable. However, when bending unfilled hollow profile bars, good results can be achieved with a split bending abutment, the abutment parts of which act on the inner wall of the profile near the flanks of the hollow profile bars.

A further development of the invention, which is suitable for a quick tool change, is the subject of claims 14 and 18.

The invention is particularly suitable for bending hollow profile bars that are still empty, in particular box profiles.

Further advantages and features of the invention will become apparent from an embodiment shown in the accompanying drawings and described below.

Figure 1 shows a simplified overall view of the device,

Figure 2 shows a part of the bending tool of the device in a front view,

Figure 3 is a plan view of the bending tool without clamping part,

Figure 4 is a sectional view of the bending tool along the line A-A in Figure 3,

Figure 5 shows an enlarged detail from Figure 4, and

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Figure 6 shows, in a view corresponding to Figure 1, the bending tool in which the counterholder is pivoted into its effective end position in which the bending abutment is ineffective.

Figure 1 shows a simplified overall view of the device with a frame 1, with a support wall 2 supported by the frame and inclined to the rear, with a horizontal conveyor track 3 provided in the lower area of the support wall 2, along which hollow profile bars to be bent are fed to a bending tool 5 in the conveying direction 4. A feed device is provided for feeding the hollow profile bars, which in the exemplary embodiment preferably consists of two endless, parallel, synchronously driven toothed belts 6 and 7, which are guided over pairs of gears 8 and 9 and 8a and 9a, by which the front gears 8, 8a are driven. In order to adapt to different profile heights of the hollow profile bars, the toothed belts 6 and 7 can be varied in their mutual distance, in particular by moving the upper toothed belt 7 together with its gears 8 and 9. Additional tools can be arranged along the conveyor track 3, in particular a saw for cutting through the hollow profile bars, a labeling device for labeling the hollow profile bars, and a connecting device for connecting successive sections of hollow profile bars. Such a connecting device consists, for example, of a stationary pair of clamping jaws 10 and a pair of clamping jaws 11 that can be moved along the conveyor track 3. In order to connect two successive hollow profile bars, the front hollow profile bar is secured near its rear end between the stationary clamping jaws 10 and the following hollow profile bar is secured near its front end between the movable clamping jaws 11, one of the two ends carrying a connector that is also pushed into the opposite end of the other hollow profile bar by moving the second pair of clamping jaws 11 forward.

The legs of the hollow profile bars to be bent are bent anti-clockwise in the device shown, in which the conveying direction 4 runs from left to right, whereby the bent legs can be supported on the supporting wall 2 and are guided on it. However, choosing the conveying direction 4 from left to right is arbitrary, it could also run from right to left; in this case the hollow profile bars would be bent clockwise.

The conveyor track 3 is not designed as a continuous track, but consists of a series of partially different elements which support and guide the hollow profile bars both parallel to the support wall 2 and in a plane perpendicular to it, thereby forcing a straight, horizontal movement path of the hollow profile bars. These elements, which determine the movement path of the hollow profile bars, include the toothed belts 6 and 7, the pairs of clamping jaws 10 and 11 and the bending tool 5, which is shown in more detail in Figure 2.

Essential components of the bending tool 5 are a bending beam 12, a counterholder 13 that works with it, a bending abutment 14 and a support 16, which is arranged on the same side of the hollow profile bar 20 as the bending system 12, specifically behind the bending beam in relation to the conveying direction 4. These components are shown in Figure 2 in a view with a viewing direction perpendicular to the support surface 2, but only the first rear abutment part 14a of the two-part bending abutment 14 is shown.

Both the bending beam 12 and its counter-holder 13 can be pivoted about a pivot axis 18 that is eccentric with respect to the bending abutment 14 and oriented at right angles to the supporting wall 2. To pivot the bending beam 12, an electric servo motor is preferably provided behind the plane of the supporting wall 2, which allows predetermined pivot angles to be carried out particularly precisely. However, it would also be possible to pivot the bending beam 12 by means of a

pneumatic cylinder, in particular a rotary wing cylinder. The counterholder 13 does not have its own swivel drive; it is driven by the bending beam 12 when the latter performs a swivel movement in the direction of arrow 19. The counterholder 13 is pressed or pulled against the section of the hollow profile bar 20 lying on the bending beam 12, preferably by means of a pneumatic cylinder, which is not shown in the drawings and whose resistance is overcome by the drive motor of the bending beam 12. The result of this is that a hollow profile bar 20 to be bent is clamped between the bending beam 12 and its counterholder 13 during the bending process. In order to prevent the counterholder 13 from pressing in the inner wall 23 of the hollow profile bar 20 adjacent to the nose 34, a stop can be provided between the bending cheek 12 and the counterholder 13, which limits the approach of the counterholder 13 to the bending cheek 12 to a dimension corresponding to the height of the hollow profile bar 20; such a stop can be formed, for example, by a screw turned into the counterholder 13 and directed against the bending cheek 12.

Before the bending beam 12 is pivoted back into its initial position shown in Figure 2, the pressure medium cylinder acting on the counterholder can be depressurized so that the counterholder remains in its position, or the pressure medium cylinder can be reversed in its direction of action so that the counterholder is pivoted into its end position shown in Figure 6, in which the bending abutment 14 has completely released the hollow profile rod 20.

The hollow profile bar 20 is fed to the bending tool on the conveyor track 3 in such a way that its outer wall 21 points downwards and rests against the bending beam 12, that its parallel flanks 22 run parallel to the supporting wall 2 and that its inner wall 23 faces the counterholder 13. The hollow profile bars 20 shown are box profiles, for which the invention is particularly suitable. In principle, however, it is also suitable for web profiles if these are to be bent while they are still unfilled.

The terms "inside" and "outside" are chosen with regard to the corner to be bent, which has an outside and an inside, so that the "inner wall" forms the inside and the "outer wall" the outside of the corner.

The support 16 can be pivoted by means of a pressure cylinder (not shown) by means of a shaft 25 running at right angles to the support wall 2. The support 16 prevents the rear section of the hollow profile bar from being deflected during bending and supports its guidance during advancement.

During the advancement of the hollow profile bar 20, the support 16 can be pivoted slightly downwards from the position shown in Figure 2 if required; the bending beam 12 is in the starting position shown in Figure 2 or, if required, in a position pivoted slightly downwards in comparison; during the advancement of the hollow profile bar 20, the counterholder 13 is preferably in the position shown in Figure 6, in which the bending abutment 14 has its greatest possible distance from the plane 17 in which the surfaces of the support 16 and the bending beam 12 facing the hollow profile bar 20 are aligned with one another in their starting position. Under these conditions, the hollow profile bar 20 is advanced by its feed device 6 to 8 between the bending abutment 14 and the counterholder 13 on one side and the support 16 and the bending beam 12 on the other side.

The hollow profile bar 20 is advanced until the point at which a corner is to be bent reaches the bending abutment 14. The correct position can be determined by a stop 27 (Figure 1) that can be moved along the conveyor track 3, against which the front end of the hollow profile bar 20 strikes and is brought to a standstill. The support 16 is then pivoted up into the plane 17 if it was not already in the plane 17. Instead of using a stop 27, the correct position can also be determined by software from specified production data and feed data.

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Spacer frames for insulating glass panes require flat, parallel flanks 22 everywhere, even in the corner area. The parallelism and flatness must not be lost by bending the corner. In order to prevent the flanks 22 of the hollow profile bars 20 from bulging during bending, they are clamped at the flanks 22. The means provided for this are shown in the top view shown in Figure 3, looking parallel to the support surface 2. The pivot axis 18 and the bending beam 12 can be seen. A carrier 32 is firmly attached to a mounting plate 30 fixed to the frame, through which a drive shaft 31 for the bending beam 12 passes, which carrier 32 replaceably carries a fixed clamping jaw 33 which faces the rear flank of the hollow profile bar, which is not shown in Figure 3. The shaft 25, which carries and rotates the support 16, is mounted in the mounting plate 30. The shaft 25 and a rod 24 parallel to it, which passes through a recess in the support 16, together carry a second clamping jaw 35, which is omitted in Figure 2 and can be moved transversely by means of a pressure cylinder (not shown). For this purpose, the shaft 25 and the rod 24 can be moved in their longitudinal direction, so that the second clamping jaw 35 can be moved in the direction of the arrow 37 towards the clamping jaw 33 and thus towards the hollow profile bar 20 in front of it. The second clamping jaw 35 also carries a jaw 38 (Figure 3), which is mounted in a recess in the second clamping jaw 35 so as to be rotatable about the pivot axis 18. The rotatable jaw 38 forms, together with another jaw 36 facing the rear flank 22 of the hollow profile bar 20, which is also mounted on an extension 12a of the bending cheek 12 so as to be rotatable about the pivot axis 18, a second clamping device with which the flanks 22 of the hollow profile bar can be clamped in the immediate vicinity of the pivot axis 18. The jaws 36 and 38 are mounted eccentrically; they extend along the leg of the hollow profile bar 20 that is to be bent over a greater length than along its non-bent leg. The rear jaw 36 is carried along by the counterholder 13. The front jaw 38 is held in a

Recess of the front jaw 38 is taken along by the counterholder 13; the engagement resembles a dovetail connection and remains shortened when the front jaw 38 increases its distance from the mounting wall 30. Because the jaws 36 and 38 can rotate with the counterholder 13 and this can be taken along by the bending cheek 12, the risk of grooves forming in the flanks 22 due to the clamping of the hollow profile bar 20 at the bending point or of the material expansion occurring during bending being uncontrollably hindered is much lower than with stationary jaws.

The arrangement and fastening of the rear, first abutment part 14a is shown in Figures 2 and 6. It is screwed with two screws 40 to the rear jaw 36, which in turn engages with a pin 42a in a bushing 43a which is arranged coaxially with the drive shaft 31 of the bending cheek 12.

The second, front abutment part 14b is, as can best be seen from Figure 5, rotatably mounted in a recess 41 of the clamping jaw 35, for which purpose the front jaw 38 has a pin 42a on its rear side, which engages in a matching bushing 43a of the clamping jaw 35. In order to hold the front jaw 38 captive in the recess 41 of the clamping jaw 35, the recess 41 is provided with an arcuate undercut 44, into which the jaw 38 engages with a corresponding arcuate projection 45, which extends approximately over a circumferential angle of 180°. During the bending process, the front jaw 38 is rotated clockwise with respect to the view shown in Figure 5, whereby the engagement of the arcuate projection 45 in the arcuate undercut 44 is maintained. To replace the front jaw 38, turn it counterclockwise, allowing the circular projection 45 to slide out of the undercut 44. As long as the positive connection between the front jaw 38 and the clamping jaw 35 is maintained, the

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When the clamping jaw 35 is adjusted, the front jaws 38 are carried along by the latter and moved into its clamping position on the hollow profile bar or moved out of the clamping position.

The front bending abutment 14b is screwed to the front jaw 38 with two screws 40. The unit thus formed has a recess 47 into which the driver 39 engages in a form-fitting manner. In this way, both abutment parts 14a and 14b are inevitably pivoted with the counterholder 13.

Figure 5 shows in detail the contour of the nose 34 of the abutment parts 14a, 14b with a substantially cylindrical first circumferential section 26a and a substantially flat second circumferential section 26b. From Figure 3 it can be seen that the nose 34 is spaced apart from the jaw 38; this distance is at least twice the wall thickness of the hollow profile bar so that the latter can be dented by the circumferential section 26a without damaging the flanks 22.

For bending, the hollow profile bar 20 is first clamped between the various clamping devices. The bending process can then be carried out by pivoting the bending cheek 12, with the greatest possible bending angle being achieved when the counterholder 13 strikes the clamping jaw 33. In order to enable the greatest possible pivoting angle, the counterholder 13 and the clamping jaw 33 are wedge-shaped, with the wedge tips directed against the bending abutment 14. An inclined surface 28 of the counterholder 13 and an inclined surface 29 of the clamping jaw 33, which lie on the side of the counterholder 13 or the clamping jaws 33 facing away from the conveyor track 3, are arranged in such a way that the counterholder 13 can strike the inclined surface 29 of the clamping jaw 33 with its inclined surface 28 over its entire surface, see Figure 6. This enables pivoting angles that are significantly greater than 90°.

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The bending abutment 14 has a first circumferential section 26a with a substantially cylindrical surface and a second, flattened circumferential section 26b, both of which lie on the same side of the pivot axis 18. Preferably, the distance of the first circumferential section 26a of the bending abutment 14 from the plane 17 in which the surfaces of the bending beam 12 and the support 16 facing the hollow profile bar 20 are aligned with one another is somewhat smaller than the height of the hollow profile bar 20, so that its inner wall 23 is dented even before the bending process, namely when the counterholder 13 and/or the bending beam 12 are pivoted into their position shown in Figure 2. The center of the bending point is then located at exactly this point. Due to the selected arrangement and shape of the second circumferential section 26b of the bending abutment 14, its distance from the plane 17 is greater than the distance of the first circumferential section 26a when the counterholder 13 is in the stop position shown in Figure 6 or in the vicinity thereof. It should also be noted that the circumferential contour is selected to be the same for both abutment parts 14a and 14b.

During bending, the support 16 prevents the section of the hollow profile bar 20 located there, in front of the bending point, from deflecting. In order to be able to transport the hollow profile bar 20 further after bending a corner, its clamp is released, the pneumatic cylinder acting on the counterholder 13 is depressurized or operated in the opposite direction and the bending beam 12 is pivoted back into its starting position (Figure 2) by its own drive. The counterholder 13, on the other hand, is pivoted in the opposite direction together with the two-part bending abutment 14 until it stops on the clamping part 15, as shown in Figure 6. The hollow profile bar 20 is then completely free of the engagement of the bending abutment 14 and can be pushed forward in the conveying direction 4 to its next bending point, at which it can be clamped again in the manner described and subsequently bent. The engagement of the bending abutment from the hollow profile bar 20 is released using the simplest means and ensures in particular that the hollow profile bar 20 is held at its

The inner wall is not touched and no grinding marks appear there, which would be particularly disturbing on painted surfaces because the inner wall of the hollow profile bar is later clearly visible in the insulating glass pane.

After the described release of the bent hollow profile bar 20 from the engagement of the bending abutment 14, it can also be completely removed from the area of the bending tool, if necessary after increasing the distance between the two abutment parts 14a and 14b to more than the width of the hollow profile bar 20.

In the device according to the invention, the hollow profile bar 20 can be clamped on both sides of the bending point, even on all sides if necessary. This means that a well-defined and - if desired - greater tension can be exerted on the outer wall 21 and on the flanks 22 during bending than in the prior art, which helps to avoid the formation of wrinkles in the area of the resulting corner and increases the quality of the bend. In addition, there is the three-sided clamping in the bending area by the jaws 36 and 38 and by the bending abutment 14. This results in an overall unmatched uniform, reproducible, attractive-looking corner formation when bending hollow profile bars 20 into spacer frames for insulating glass panes.

The counterholder 13 can be exchanged together with the bending abutment 14 and replaced by an arrangement that is particularly suitable for bending hollow profile bars filled with desiccant, consisting of a counterholder, bending abutment and a clamping part opposite the support 16, against which the support 16 can clamp the hollow profile bar 20 and in which the bending abutment is formed by a hinge-like connection of the counterholder to the clamping part. Such a hinge-like design of the bending abutment makes it particularly resistant to the greater forces that occur when bending filled hollow profile bars, despite its small dimensions. An example

of such a bending tool is disclosed in the German patent application 101 38 345.2. For the purpose of replacement, the counterholder 13 has an elongated hole-like recess 46 at its end facing away from the pivot axis 18, which is open towards the end of the counterholder 13. In the counterholder 13 there is also a bore 48 parallel to the pivot axis 18, which lies between the recess 46 and the bending abutment 14. A pin 49 is inserted into a bore of a carrier 57 for the counterholder 13 that can pivot about the pivot axis 18, and parallel to this there is another axially parallel bore 50 in the carrier 57, which is at a distance from the pin 49 that corresponds to the distance of the bore 48 from the recess 46.

A locking pin 52 is inserted into the bore 50 and is secured against moving out by a spring-loaded pressure piece 54. After loosening the grub screw 54, the locking pin 52 can be pulled out and the counterholder 13 removed. This enables a lightning-fast tool change.

-25-Reference number list:

1 Posted

2 retaining wall

3 Conveyor track

4 Conveying direction

5 Bending tool

6 Toothed belt of the feed device

7 Toothed belt of the feed device

8 Gears of the feed device 8a Gears of the feed device

9 Gears of the feed device 9a Gears of the feed device

10 stationary jaw pair

11 Movable pair of clamping jaws 12 Bending beam 12a Extension of the bending beam, part of the second clamping device

13 Counterholder

14 Bending abutments

14a first rear abutment part 14b second front abutment part

15 Clamping part of a first clamping device

16 Support, part of the first clamping device

17 Level

18 Swivel axis 19 Arrow

20 hollow profile bar

21 Exterior wall

22 flanks

23 Inner wall 24 Rod

25 Shaft of 16 26a First circumferential section 26b Second circumferential section 27 Stop 28 Inclined surface

29 Inclined surface

30 Mounting plate

31 Drive shaft

32 carriers

33 Clamping jaw of the third clamping device

34 Nose

35 second clamping jaw of the third clamping device

36 rear jaw, part of the second clamping device

37 Arrow

38 front jaw, part of the second clamping device

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39 Carrier

40 screws

41 Recess

42 Pin 43 Socket

44 Backstep

45 lead

46 Recess in

47 Recess 48 Hole in

49 first pin

50 Hole in 12a 52 Locking pin 54 Spring pressure piece 57 Support for the counterholder

Claims (25)

1. Device for bending hollow profile bars ( 20 ), in particular for spacer frames for insulating glass panes, wherein the hollow profile bars ( 20 ) have two mutually parallel flanks ( 22 ) and an inner wall ( 23 ) and an outer wall ( 21 ) which connect the flanks ( 22 ) to one another, - with a frame ( 1 ), - with a bending tool ( 5 ) carried by the frame ( 1 ), which - has a bending beam ( 12 ) which can be pivoted about a pivot axis ( 18 ) and acts on the outer wall ( 21 ) of the hollow profile bar ( 20 ) for bending
and has an initial position which it assumes before bending, - has a bending abutment ( 14 ) facing the inner wall ( 23 ), around which the hollow profile bar ( 20 ) is bent, and which has two abutment parts ( 14 a, 14 b) whose mutual distance is variable, - and a support ( 16 ) for supporting the outer wall ( 21 ) of the hollow profile bar ( 20 ), which is arranged on the side of its pivot axis ( 18 ) facing away from the starting point of the bending beam ( 12 ) characterized in that the bending abutment ( 14 ) can be pivoted by means of its own drive about the pivot axis ( 18 ) of the bending beam ( 12 ) or about an axis adjacent to and parallel to it, and that the two abutment parts ( 14a , 14b ) have an eccentric shape with respect to their pivot axis ( 18 ) in such a way that they have a first circumferential section ( 26a ) which bears against the inner wall ( 23 ) of the hollow profile bar ( 20 ) during the bending process, and that they have a second circumferential section ( 26a ) adjoining the first circumferential section ( 26a ) which can be turned towards the inner wall ( 23 ) of the hollow profile bar ( 20 ) by pivoting the bending abutment ( 14 ) and in the then given position from the plane ( 17 ) in which the side of the Support ( 16 ) and the bending cheek ( 12 ) are aligned with each other, have a greater distance than the first peripheral portion ( 26a ) in its position facing this plane ( 17 ). 2. Device according to claim 1, characterized in that the bending abutment ( 14 ) can optionally also be pivoted together with the bending beam ( 12 ) about its pivot axis ( 18 ). 3. Device according to claim 1 or 2, characterized in that the bending abutment ( 14 ) or one of its parts 14a is arranged at the tip of a counterholder ( 13) opposite the bending cheek (12 ) , which is designed to rest against the inner wall ( 23 ) of the hollow profile rod ( 20 ). 4. Device according to claim 3, characterized in that the surface of the counterholder ( 13 ) facing the inner wall ( 23 ) of the hollow profile rod ( 20 ) is flat. 5. Device according to claim 3 or 4, characterized in that the counterholder ( 13 ) is wedge-shaped, the wedge tip pointing towards the bending abutment ( 14 ). 6. Device according to one of the preceding claims, characterized in that the support ( 16 ) is pivotable about an axis ( 25 ) parallel to the pivot axis ( 18 ). 7. Device according to claim 6, characterized in that in the vicinity of the support ( 16 ) a rear clamping jaw ( 13 ) and a front clamping jaw ( 35 ) are provided, which are intended for clamping the flanks ( 22 ) of the hollow profile bar ( 20 ), and that the rear clamping jaw ( 33 ) is wedge-shaped, the wedge tip pointing towards the bending abutment ( 14 ). 8. Device according to claim 7, characterized in that the wedge surface of the counterholder ( 13 ) can be brought into flat contact with the contact of the rear clamping jaw ( 33 ) facing it by pivoting the counterholder ( 13 ). 9. Device according to claim 7 or 8, characterized in that the wedge angles of the counterholder ( 13 ) and the rear clamping jaw ( 33 ) taken together are less than 50°, in particular less than 30°. 10. Device according to one of the preceding claims, characterized in that the abutment parts ( 14 a, 14 b) have a predominantly cylindrical outer surface in a first circumferential section ( 26 a). 11. Device according to claim 10, characterized in that for the bending of hollow profile bars ( 20 ) with a box-shaped cross-section (box profiles), the radius of the lateral surface of the first circumferential section ( 26a ) is 2 mm to 3 mm, in particular 2.5 mm. 12. Device according to one of the preceding claims, characterized in that both abutment parts ( 14 a, 14 b) have a matching contour in their first peripheral section ( 26 a), which faces the hollow profile bar 20 during bending. 13. Device according to one of the preceding claims, characterized in that the abutment parts ( 14 a, 14 b) have a flattened second circumferential portion ( 26 a) on their rear side, which faces away from the first circumferential portion ( 26 a). 14. Device according to one of the preceding claims, characterized in that the first and the second peripheral portion ( 26a ) both lie on the same side of the pivot axis ( 18 ). 15. Device according to one of the preceding claims, characterized in that the bending abutment ( 14 ) is replaceable. 16. Device according to claim 15, characterized in that the bending abutment ( 14 ) is detachably fastened to a support ( 57 ) pivotable about the pivot axis ( 18 ) of the bending beam ( 12 ). 17. Device according to claim 16, characterized in that the counterholder ( 13 ) has a recess ( 46 ) open towards its end facing away from the pivot axis ( 18 ), that an axially parallel pin ( 49 ) protrudes from the pivotable support ( 57 ) and is intended to engage in the recess ( 46 ), and that means ( 52 ) are provided for fixing the bending abutment ( 14 ) with the counterholder ( 13 ) on the pivotable support ( 57 ), which means additionally releasably hold the counterholder ( 13 ) on the pivotable support ( 57 ) at a point remote from the pin ( 49 ). 18. Device according to claim 17, characterized in that for fixing the counterholder ( 13 ) together with the bending abutment ( 14 ) a pin ( 52 ) or a screw is provided which is introduced through the counterholder ( 13 ) into the carrier ( 57 ) which can be pivoted with the bending cheek ( 12 ) or relative to the bending cheek ( 12 ). 19. Device according to one of the preceding claims, characterized in that in the region of the pivot axis ( 18 ) a second clamping device ( 12a , 38 ) acting on the flanks ( 22 ) of the hollow profile bar ( 20 ) is provided. 20. Device according to claim 19, characterized in that the second clamping device ( 12a , 38 ) is pivotable with the bending abutment. 21. Device according to claim 20, characterized in that the one abutment part ( 14a ) is coupled to a rear jaw ( 36 ) of the second clamping device and the other abutment part ( 14b ) is coupled to a front jaw ( 38 ) of the second clamping device, the distance of which from the rear jaw ( 36 ) of the second clamping device is variable. 22. Device according to claim 21, characterized in that the abutment parts ( 14 a, 14 b) are detachably coupled to the jaws ( 36 , 38 ). 23. Device according to claim 21 or 22, characterized in that a driver ( 39 ) is attached to the counterholder ( 13 ) and/or to the first abutment part ( 14a ) attached thereto, which driver engages the second abutment part ( 14b ) and/or the second, distance-variable part ( 38 ) of the second clamping device and takes it along. 24. Device according to one of the preceding claims, characterized in that a third clamping device ( 33 , 35 ) acting on the flanks ( 22 ) of the hollow profile bar ( 20 ) is provided on the side of the pivot axis ( 18 ) facing away from the bending beam ( 12 ) in its initial position. 25. Device according to one of the preceding claims, characterized in that a fourth clamping device ( 40 , 41 ) which can be pivoted with the bending beam ( 12 ) and acts on the flanks ( 22 ) of the hollow profile bar ( 20 ) is connected to the bending beam (12).