EP0445044A1 - Bending machine with two bending heads - Google Patents

Abstract

The machine is provided with two bending heads (9,10) both of which can be moved in the initial direction of the tube (12) to be bent and each of which is equipped with a bending tool working in a bending plane whose orientation can be varied. <??>At least one of the bending heads (9,10) is also moveable in a plane perpendicular to the initial direction of the tube (12) and carries means (27,29) for gripping the said tube which are offset in relation to the longitudinal axis of the head. Thus, this head may be moved away from the initial axis (11) of the tube, the associated gripping means (27,29) then coming into this axis and being able to hold the tube (12) there temporarily. <??>This arrangement enables very closely spaced elbows to be formed in the central region of the tube.

Description

The present invention relates to a machine for bending tubes. More particularly, this invention relates to a machine provided with two bending heads, movable one and the other in the initial direction of the tube to be bent, and each equipped with a bending tool working in a plane of bending whose orientation is modifiable by the action of control means and may be different from the orientation of the bending plane in which the other bending head works.

Machines for bending tubes of this kind, and rotating bending heads adapted to these machines, are already described for example in French patent application No. 2,610,852, or in European patent application No. 0 281 488 in the name of the Applicant.

In such known bending machines, the two bending heads are usually arranged on either side of a fixed or rotating central clamp, provided for holding the tube to be bent. During a bending process, the two bending heads, working simultaneously or alternately, are gradually brought closer to the central clamp, each bending head making it possible to make several successive bends on the corresponding half of tube, the different bends being able to locate in separate planes from each other. It is understood that bending machines of this kind make it possible to produce multiple bends with high efficiency, on tubes of relatively great length, and thus these machines find applications in particular in the field of the automobile industry, for example for the production of conduits for braking circuits.

However, these machines for bending tubes still retain drawbacks which limit their possibilities of use. In particular, taking into account the usual presence of the central clamp, it remains difficult, if not impossible, to produce close bends in the central region of the tube. Indeed, this central region is clamped in the central clamp, which constitutes an obstacle limiting the translational movement of the two bending heads in the direction of their approximation. Thus, unless provision is made for special devices, the minimum distance between two elbows, in the central region of the tube, is at least twice the length of a bending head, increased by the width of the central clamp.

The simple removal of this central clamp cannot constitute a valid solution to the problem posed above, because it remains necessary to hold the tube during the execution of the last bend (s) in its middle region.

The present invention aims to eliminate these drawbacks by providing a machine for bending tubes of the type under consideration, effectively making it possible to produce very close bends in the median region of the tube, while always ensuring correct immobilization of the latter.

To this end, the subject of the invention is a machine for bending tubes with two bending heads, of the type specified in the introduction, in which at least one of the two bending heads is provided to be movable also in a plane perpendicular to the initial direction of the tube to be bent, and carries means for pinching said tube, offset with respect to the longitudinal axis of the bending head, so that this bending head can be moved away from the initial axis of the tube to be bent , the associated pinching means then coming in this axis and being able to temporarily hold the tube to be bent there.

Thus, the machine for bending tubes according to the invention is devoid of central clamp, without this affecting its operation: its two bending heads are actuated alternately, one of the heads producing an elbow on the tube in the plane of desired bending while the other head maintains the same tube. When the two bending heads reach the median region of the tube, one of the heads can slip away, for example behind this tube, so that it no longer constitutes an obstacle to an additional advance of the other head bending, for the realization of a last bend which can be very close to that previously formed. While the last bend is produced by this other bending head, the tube is held tight by the clamping means carried by the clamping head which has been moved away from the initial axis of the tube.

Preferably, the two bending heads of the machine are both provided in a plane perpendicular to the initial direction of the tube to be bent, so as to be able to be separated each from the initial axis of the tube to be bent, and each bending head carries means for pinching said tube, offset with respect to the longitudinal axis of this head.

According to one embodiment of the invention, each bending head is carried by the free end of a support arm pivotally mounted, about an axis parallel to the initial direction of the tube to be bent, on a part of a carriage which can itself be moved in this direction, and motorized control means are provided for actuating the pivoting support arm, so as to separate the corresponding bending head from the initial axis of the tube to be bent, or to return said bending head to this axis. The motorized control means can here be constituted by a jack, mounted between a part of the carriage and the pivoting support arm of the bending head.

In one embodiment of the invention, each bending head is itself provided, towards its end situated on the side of its bending tool, with a support rod substantially perpendicular to the initial direction of the tube to be bent, this support rod being provided at its free end with the aforementioned clamping means. The latter can be produced in the form of a clamp with two opposite jaws, pivoting symmetrically under the action of motorized control means. The distance between the clamp and the longitudinal axis of the bending head defines the distance by which this head must be offset, to bring the clamp into its active position, where it can temporarily hold the tube to be bent.

The pinching means can be fixedly mounted on the associated bending head. These means can also be provided retractable, so as not to constitute obstacles when they do not intervene, and in particular so as not to hinder the movement of the tube during bending.

• Figure 1 est une vue d'ensemble, en perspective, d'une machine à cintrer les tubes à deux têtes de cintrage, conforme à la présente invention ;
• Figure 2 est une vue en bout, avec coupe partielle, de la machine de figure 1, montrant une tête de cintrage en position normale de travail ;
• Figure 3 est une vue de côté d'une tête de cintrage de cette machine ;
• Figure 4 est une vue en bout de la tête de cintrage de figure 3 ;
• Figures 5,6,7,8 et 9 sont des schémas illustrant le fonctionnement de la machine, pour la réalisation de coudes rapprochés dans la région médiane d'un tube ;
• Figure 10 est une vue en bout similaire à figure 2, mais montrant la tête de cintrage en position écartée de l'axe initial du tube à cintrer.

In any case, the invention will be better understood with the aid of the description which follows, with reference to the appended schematic drawing showing, by way of nonlimiting example, an embodiment of this machine for bending tubes:

• Figure 1 is an overall perspective view of a machine for bending tubes with two bending heads, according to the present invention;
• Figure 2 is an end view, partly in section, of the machine of Figure 1, showing a bending head in the normal working position;
• Figure 3 is a side view of a bending head of this machine;
• Figure 4 is an end view of the bending head of Figure 3;
• Figures 5,6,7,8 and 9 are diagrams illustrating the operation of the machine, for the production of close bends in the middle region of a tube;
• Figure 10 is an end view similar to Figure 2, but showing the bending head in the position away from the initial axis of the tube to be bent.

The machine for bending tubes, shown as a whole in Figure 1, comprises a bench 1 elongated in the horizontal direction. The bench 1 comprises two parallel horizontal guide columns 2 and 3, along which are movable in translation two carriages 4 and 5. The first carriage 4 is equipped with a gear motor 6 controlling its movement along the guide columns 2 and 3, by means of a not shown pinion which engages with a horizontal rack 7 carried by the bench 1. The second carriage 5 is also equipped with a geared motor 8 controlling its movement along the columns of guide 2 and 3, by means of a pinion which engages with the same rack 7.

The first carriage 4 carries a first bending head 9, and the second carriage 5 carries a second bending head 10, the two bending heads 9 and 10 being normally positioned along the same horizontal axis 11, along which the tube is also arranged to bend 12, initially straight. Thus, by the displacement of the respective carriages 4 and 5, the two bending heads 9 and 10 can be moved one and the other horizontally in the initial direction of the tube to be bent 12.

More particularly, and with reference also to FIG. 2, each carriage 4 or 5 has an upwardly facing part, respectively 13 or 14. At the top of this part 13 or 14 is pivotally mounted, around a horizontal axis 15 parallel to the initial direction of the tube to be bent 12, a support arm respectively 16 or 17. The first bending head 9 is carried by the free end of the pivoting support arm 16 associated with the first carriage 4, and the second head bending 10 is carried by the free end of the pivoting support arm 17 associated with the second carriage 5.

A jack 18 is mounted between the part 13 of the first carriage 4 and a point of the associated support arm 16, to control a pivoting of this support arm 16 around the axis 15, and thus move the first bending head 9 on a circular path 19, in a plane perpendicular to the initial direction of the tube to be bent 12. The first bending head 9 can thus be moved away from the initial axis 11 of the tube to be bent.

Similarly, another jack 20 is mounted between the part 14 of the second carriage 5 and a point of the associated support arm 17, to control a pivoting of this support arm 17 around the axis 15, and thus move the second head bending 10 on a circular path, in a plane perpendicular to the initial direction of the tube to be bent 12. The second bending head 10 can thus also be spaced from the initial axis 11 of the tube to be bent.

With reference also to FIGS. 3 and 4, each bending head 9 or 10 has a body with a cylindrical appearance, having a longitudinal slot 21 which allows the lateral insertion and exit of the tube to be bent 12. At its outer end, that is to say distant from the other head, each bending head 9 or 10 comprises a bending tool of known type, essentially constituted by a forming roller 22 and by a bending roller 23, the latter being carried by a pivoting radial arm 24 and thus able to rotate around the forming roller 22. All the bending tools are mounted rotating around the longitudinal axis of the bending head 9 or 10, so as to modify the orientation of the bending plane . Motorized control means, indicated generally at 25 in FIGS. 2 and 3 and which may include two geared motors and mechanical transmission members, are provided, on the one hand, to modify the orientation of the bending plane and , on the other hand, actuate the radial arm 24. As regards the detailed structure of such a rotating bending head and its control members, reference may usefully be made to the description and figures of the application for European patent N ° 0 281 488 in the name of the Applicant.

The body of the first bending head 9 is provided, on the side of the bending tool, with a support rod 26 substantially perpendicular to the longitudinal axis of this head, as well as to the direction of the support arm 16 of this head 9. At its free end, the support rod 26 is provided with clamping means, generally designated by 27.

Symmetrically, the body of the second bending head 10 is provided, on the side of the bending tool, with a support rod 28 substantially perpendicular to the longitudinal axis of this head, as well as to the direction of the support arm 17 of this head 10. At its free end, the support rod 28 is provided with pinching means, generally designated by 29.

The clamping means 27 or 29 can be produced, as shown in particular in FIG. 4, in the form of a clamp with two opposite jaws 30 and 31, which can pivot symmetrically between an open position and a closed position under the action of motorized control means 32. The clamp is designed to grip the tube to be bent 12 between its two jaws 30 and 31. D denotes the distance which separates this clamp from the longitudinal axis of the bending head.

In the embodiment considered, again referring to Figures 1 and 2, the bending machine further comprises an automatic handling device, generally designated by 32. The handling device 32 comprises a support leg 33, fixed to the middle of the bench 1 and carrying a double loading arm 34, pivotally mounted about a horizontal axis 35 parallel to the initial axis 11 of the tube to be bent. Gripping means 36, for example magnetic, capable of retaining a tube, are provided at the ends of the arms of the double loading arm 34. The waiting tubes 12 rest on an inclined plane 37. The double loading arm 34 picks up the tube 12 located at the lowest point of the inclined plane 37, and it brings this tube, by a movement in an arc 38, as far as the axis 11 along which the two bending heads 9 and 10 normally move. These heads 9 and 10 then being spaced apart as shown in FIG. 10, and sufficiently distant from one another to allow the passage of the double loading arm 34 (or, possibly, sufficiently close to one another to allow the two loading arm to pass on either side of the two heads 9 and 10).

The two bending heads 9 and 10 are then brought back in the axis 11 to take up the tube to be bent 12. These heads 9 and 10 are then spaced from one another, in the direction of the ends of the tube 12, and they can thus come up to the stop against end caps or nuts provided at the ends of the tube 12. Finally the double arm 34 of the handling device 32 is returned to its starting position, at the lowest point of the inclined plane 37, s' it has not been previously retracted.

Then, the two bending heads 9 and 10, remaining in the normal working position on the axis 11 (see FIG. 2), moved alternately one towards the other along this axis 11, to execute bends alternately on the two halves of the tube to be bent 12. While a bending head 9 or 10 bends the desired angle in the corresponding tube half, this according to a bending plane determined by the orientation of its bending tools , the other bending head 10 or 9 maintains the tube 12 in the corresponding half. One of the bending heads 9 or 10 also maintains the tube 12 during bending while the other head is moved along the axis 11. This alternative bending process can continue, until the two heads 9 and 10 arrive in close proximity to each other, as shown in Figure 5, in the middle region of the tube 12.

This FIG. 5 shows that the last two elbows, which can be produced on the tube 12 by means of the respective bending tools of the two heads 9 and 10, are then separated at least by a distance E equal to substantially twice the length of a head of bending.

To make at least one additional bend in the middle region of the same tube 12, the bending roller 23 of the first head 9 for example is first brought back to the starting position (corresponding to a zero bending angle), as shown Figure 6.

Then, as illustrated in FIG. 7 and also in FIG. 10, the first bending head 9 is spaced from the initial axis 11 of the tube 12, over a distance D, so that the clamping means 27 carried by this head 9 is placed in the axis 11. The pinching means 27 are then actuated so as to firmly hold the tube 12, in its rectilinear part located between the last two elbows formed.

The second bending head 10 is then moved along the axis 11 in the direction of the clamping means 27, without encountering any obstacle since the first head 9 has been previously overshadowed. This additional movement is illustrated in Figure 8.

Finally, an additional bend is made on the tube 12 by means of the second bending head 10, brought closer to the pinching means 27, as shown in FIG. 9. Thus, the last two elbows made on the tube 12 are separated by a distance e which is clearly less than distance E and which can be approximately equal to half of distance E.

Of course, given the symmetry of the machine, the roles of the two bending heads 9 and 10 can be reversed in the process which has just been described.

It goes without saying that the invention is not limited to the only embodiment of this tube bending machine which has been described above, by way of example; on the contrary, it embraces all the variants respecting the same principle. Thus, one would not depart from the scope of the present invention by using all equivalents, in particular for the means for controlling the various movements, or even by providing additional arrangements, such as a system for retracting the means pinching the tube carried by the bending heads.

Claims (8)

Tube bending machine provided with two bending heads (9,10), each movable in the initial direction of the bending tube (12), and each equipped with a bending tool (22 , 23, 24) working in a bending plane, the orientation of which can be modified by the action of control means (25) and may be different from the orientation of the bending plane in which the other bending head works, characterized in that at least one of the two bending heads (9,10) is provided movable also in a plane perpendicular to the initial direction of the tube to be bent (12), and carries clamping means (27,29) of said tube (12), offset with respect to the longitudinal axis of the bending head (9,10), so that this bending head (9,10) can be moved away from the initial axis (11) of the tube to be bent, the pinching means (27,29) associated then coming in this axis (11) and being able to temporarily hold the tube therein to bend (12). Machine for bending tubes with two bending heads, according to claim 1, characterized in that the two bending heads (9, 10) are both provided movable in a plane perpendicular to the initial direction of the tube to be bent (12), so that each can be moved away from the initial axis (11) of the tube to be bent, and in that each bending head (9,10) carries gripping means (27,29) of said tube (12), offset from the longitudinal axis of this head. Machine for bending tubes with two bending heads, according to claim 2, characterized in that each bending head (9,10) is carried by the free end of a support arm (16,17) pivotally mounted, about an axis (15) parallel to the initial direction of the tube to be bent (12), on a part (13,14) of a carriage (4,5) itself movable in this direction, and in that motorized control means (18,20) are provided for actuating the pivoting support arm (16,17) so as to separate the corresponding bending head (9,10) from the initial axis (11) of the tube to be bent , or to bring back said bending head (9,10) on this axis (11). Machine for bending tubes with two bending heads, according to claim 3, characterized in that the motorized control means consist of a jack (18,20) mounted between a part (13,14) of the carriage (4,5 ) and the pivoting support arm (16,17) of the bending head (9,10). Machine for bending tubes with two bending heads, according to any one of Claims 2 to 4, characterized in that each bending head (9,10) is itself provided, towards its end situated on the side of its bending tool (22,23,24), with a support rod (26,28) substantially perpendicular to the initial direction bending tube (12), this support rod (26,28) being provided at its free end with the clamping means (27,29) mentioned above. Machine for bending tubes with two bending heads, according to claim 5, characterized in that the clamping means (27,29) associated with each bending head (9,10) are produced in the form of a pliers two opposite jaws (30,31), pivoting symmetrically under the action of motorized control means (32). Machine for bending tubes with two bending heads, according to any one of claims 1 to 6, characterized in that the clamping means (26,27) are fixedly mounted on the associated bending head (9,10). Machine for bending tubes with two bending heads, according to any one of Claims 1 to 6, characterized in that the clamping means (26, 27) are provided retractable.

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