EP0281488A1 - Turning bending head for a tube-bending machine - Google Patents

Abstract

This bending head (11) may equip machines with a single bending head or with two bending heads. A central shaft (16) is rotatably mounted, about the axis (5) of the tube to be bent (4), in a body (14) which cannot rotate. Control means (17,19,20) make it possible to change the angular position of the shaft (16), the front part (18) of which supports bending tools (26,27) placed in front of the body (14) so as to change the orientation of the bending plane. Other control means (29 to 37) serve for actuating the bending tools. <IMAGE>

Description

The present invention relates to a rotating bending head, intended to equip a machine for bending tubes, or other similar elongated objects, provided either with a single bending head or with two bending heads.

In tube bending machines, the bending heads usually work in an invariable plane, which is generally a horizontal plane. The tube to be bent is held by means of pliers, which can be rotated by the axis of the tube to be bent, to modify the angular position of this tube and thus determine the planes in which the bending operations.

Rotating bending heads are also known, that is to say mounted rotatably around the axis of the tube to be bent - see for example French patent FR-B-2 311 604. If such a head is used bending, the tube to be bent can remain immobilized in rotation on the machine; it is the rotation of the bending head which determines, and makes it possible to modify, the orientation of the bending plane relative to the tube.

The use of rotating bending heads has already been envisaged, on the one hand, in machines for bending tubes with a single bending head - see patent US-A-3,373,587 and, on the other hand, in machines for bending tubes provided with two bending heads arranged on either side of a central clamp - see European patent application EP-A-0 121 077. This kind of bending heads is particularly interesting in the case of machines with two heads, because it allows to form simultaneously, on the same tube, two elbows located in different planes.

Rotating bending heads, currently known, however have various drawbacks, due to which the use of these heads has so far hardly spread in the industry. In particular :
- These bending heads often having heavy and bulky rotating parts, such as motors necessary to control certain movements of the bending tools.
- It is impossible to rotate these bending heads through 360 °, either because of their design or because of the supply hoses of the engines running with these heads.
- The size of the known rotating bending heads is important, especially in the direction of the axis of the tube to be bent. This last drawback appears to be annoying, especially in the case of machines with two bending heads, because it prevents the production of very close bends on the same tube.

The present invention aims to avoid all of these drawbacks by providing a compact, rotating bending head capable of describing rotation over angles of 360 ° or more without any limitation, and comprising a minimum of rotating parts, all the motors necessary for the control of the head functions can in particular be fixed.

To this end, the rotating bending head which is the subject of the present invention essentially comprises, in combination:
- a tubular body with a horizontal axis, coincident with the axis of the tube to be bent and immobilized in rotation,
a central shaft mounted rotating in the body around the latter's axis, and comprising an enlarged front part supporting bending tools, placed in front of said body,
control means provided for modifying the angular position of the central shaft, therefore the orientation of the bending plane, and
- Other control means for actuating the bending tools, these other control means comprising at least one control member slidably mounted parallel to the axis of the bending head, between the tubular body, and the shaft central of it.

Thus, the bending head object of the invention has a non-rotating body, simply positioned axially in the desired position relative to the tube to be bent, and a part which, to allow the orientation of the bending plane to be chosen, can be animated in a rotary motion. For the control of this rotary movement, the central shaft of the bending head may comprise, at one end, a bevel drive pinion, while a gear motor is coupled to another bevel gear engaged with the previous one . The two bevel gears make it possible to arrange the gear motor perpendicular to the general axis of the bending head, which makes the bending head compact.

An even more compact, and in particular shorter, embodiment of the rotating bending head which is the subject of the invention can be obtained by providing, for controlling the rotary movement, that the enlarged part of the central shaft has at its periphery a circular toothing in engagement with a tangent screw, of axis orthogonal to that of the bending head, which is coupled to a drive motor.

According to a particular embodiment of this rotating bending head, the enlarged part of the central shaft is extended by a lug which extends outside the tubular body and which supports the bending tools; these tools comprise on the one hand a bending roller mounted at the free end of an arm itself mounted rotating on the tab, around an axis orthogonal to the horizontal axis of the tubular body, and on the other hand a forming roller mounted along the same axis as the arm.

To actuate the bending tools, it is necessary to provide control means capable of acting effectively, whatever the bending plane in which these tools are positioned. For this purpose, the control means for actuating the bending tools advantageously comprise, on each bending head, a slide with longitudinal slot, movable in translation inside the tubular body along the axis of the latter, and a pusher eccentric with respect to the central shaft and having one end connected to the slide, while its other end is linked to the arm carrying the bending roller, the connection between the pusher and the slide allowing rotation of the pusher relative to the slide . One end of the pusher forms for example an enlarged head, introduced into an annular groove of the slide. This makes it possible to actuate the pusher by means of a slide occupying an invariable angular position, while this pusher has a variable angular position according to the bending plane, the angular positioning of the pusher being able to be ensured by providing that this pusher passes through sliding the widened part of the central shaft.

Towards its end remote from the slide, the pusher may include a rack engaging a pinion which is integral with the arm on which the bending roller is mounted. The translational movement of the plunger is thus transformed into a rotary movement of the arm, therefore of the bending roller which wraps the tube to be bent around the forming roller.

According to another characteristic, the slide itself comprises laterally, a rack which engages with a drive pinion, coupled to a gear motor. The latter therefore controls the movement of the bending roller by means of: a first rack and pinion mechanism, the slide, the plunger, a second pinion-rack and arm mechanism. The geared motor considered is arranged perpendicular to the general axis of the bending head, which makes it possible to keep a compact assembly, and above all this geared motor can remain fixed, therefore is not a rotating part around the axis of the bending head, although it actuates members which themselves are mounted to rotate about this axis.

In the case of the application of the rotating bending head, object of the invention, to a machine for bending tubes with a single head, the various coaxial organs that are the body, the central shaft with its enlarged part and the Slide can be, simply, fully tubular shaping members.

On the other hand, in the case of a head intended for a bending machine with two bending heads, longitudinal slots are provided respectively on the body of the bending head, on the central shaft with enlarged part, and on the slide. used to control the bending tools, these slots being necessary to allow the initial introduction of the tube to be bent, and the withdrawal of this tube after completion of the bending operations. Aside from the presence or absence of the longitudinal slots, the design of the bending head can be identical, whether it is a head for a bending machine with one head or with two heads.

• Figure 1 est une vue de côté d'une machine à cintrer les tubes, pourvue de deux têtes de cintrage réalisées conformément à la présente invention ;
• Figure 2 est une vue en coupe longitudinale de l'une des deux têtes de cintrage de la machine selon la figure 1 ;
• Figure 3 est une vue en coupe transversale de cette tête de cintrage, selon III-III de figure 2 ;
• Figure 4 est une vue en coupe suivant IV-IV de figure 2, passant par les outils de cintrage ;
• Figure 5 est une vue en coupe longitudinale, similaire à figure 1, relative à une variante de cette tête de cintrage, destinée à une machine à cintrer les tubes avec tête unique ;
• Figure 6 est une vue de côté d'une autre forme de réalisation de tête de cintrage conforme à l'invention, destinée à une machine à cintrer les tubes avec deux têtes ;
• Figure 7 est une vue en coupe longitudinale de la tête de cintrage de figure 6 ;
• Figures 8 et 9 sont des vues en coupe transversale de cette dernière tête, respectivement suivant VIII-VIII et IX-IX de figure 7.

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 examples, some embodiments of this rotating bending head:

• Figure 1 is a side view of a tube bending machine, provided with two bending heads made in accordance with the present invention;
• Figure 2 is a longitudinal sectional view of one of the two bending heads of the machine according to Figure 1;
• Figure 3 is a cross-sectional view of this bending head, according to III-III of Figure 2;
• Figure 4 is a sectional view along IV-IV of Figure 2, passing through the bending tools;
• Figure 5 is a longitudinal sectional view, similar to Figure 1, relating to a variant of this bending head, intended for a machine for bending tubes with a single head;
• Figure 6 is a side view of another embodiment of the bending head according to the invention, for a machine for bending tubes with two heads;
• Figure 7 is a longitudinal sectional view of the bending head of Figure 6;
• Figures 8 and 9 are cross-sectional views of the latter head, respectively along line VIII-VIII and IX-IX of Figure 7.

The bending machine, shown as a whole in Figure 1, comprises a bench 1 elongated in the horizontal direction. The bench 1 comprises, substantially at mid-length, a column 2 which supports, at its top, a clamp 3 arranged so as to maintain a tube 4 to be bent. The middle part of the tube 4, clamped in the clamp 3, is held in the direction of a horizontal axis 5.

The bench 1 carries, on either side of the support column 2, horizontal guide columns respectively designated by 6 and 7, along which are movable in horizontal translation of the respective carriages 8 and 9. The first carriage 8 is equipped at its lower part with a geared motor 10 for its translational drive along the guide columns 6, for example by a mechanism of the rack and pinion type, and it carries at its upper part a first bending head 11. Symmetrically, the second carriage 9 is equipped at its lower part with a geared motor 12 for its translational drive along the guide columns 7, and it carries at its upper part a second bending head 13. The two bending heads 11 and 13 are arranged on either side of the central clamp 3, on the axis 5, at a distance from the clamp 3 which is variable according to the position of the carriages 8 and 9. It has been indicated for example, in Figure 1, a posit ion of carriages 8 and 9 and bending heads 11 and 13 close to the central clamp 3 (drawn in solid lines), and a position remote from this central clamp (drawn in broken lines).

Figures 2 and 3 show the detail of a bending head 11, the other bending head 13 having the same structure with a symmetrical arrangement or rotated by 180 °.

The bending head 11 considered here has a body 14 of cylindrical shape, split longitudinally, which is rigidly connected to the carriage 8. The longitudinal slot 15 of the body 14 has a width provided so as to allow the passage of the tube 4 to be bent.

Inside the body 14 is rotatably mounted, along the horizontal axis 5, a central shaft 16 which comprises, at one end, a bevel gear 17 and, at its other end, an enlarged part 18 fitting into the body 14. The bevel gear 17 is engaged with another bevel gear 19, of vertical axis, which is coupled to a geared motor 20 carried by the carriage 8 (see also Figure 1). The central shaft 16 also has a longitudinal slot 21, allowing the passage of the tube 4 to be bent. The slot 21 is formed between two successive teeth of the bevel gear 17.

The enlarged part 18 of the shaft 16 is extended, outside the body 14 and on the side opposite to the central clamp, by a lug 22. At the free end of the lug 22 is rotatably mounted, around a axis 23 orthogonal to the horizontal axis 5, an assembly comprising a pinion 24 mounted along the axis 23, a radial arm 25 secured to the pinion 24, and a bending roller 26 mounted at the end of the arm 25. In addition, the free end of the tab 22 carries a forming roller 27 mounted along the axis 23. The tube 4 to be bent passes between the two rollers 26 and 27.

In the annular space 28 located between the body 14 and the shaft 16 is housed a cylindrical slide 29 having at one end an annular groove 30. A pusher 31, parallel to the axis 5 and eccentric relative to this axis, crosses slidingly the enlarged part 18 of the shaft 16. One end of the pusher 31 forms an enlarged head 32, introduced into the annular groove 30 of the slider 29. Towards its other end, the pusher 31 laterally comprises a rack 33, coming in taken with the pinion 24 secured to the arm 25.

The slider 29 itself comprises, laterally, a rack 34 which engages a drive pinion 35, which is coupled to a gear motor 36 placed under the body 14 (see also Figure 1). This slider 29 is split longitudinally, like the body 14 and the shaft 16, the longitudinal slot 37 of the slider 29 being formed in correspondence with that 15 of the body 14.

At the start of an operating cycle, the central shaft 16 is angularly positioned so that its longitudinal slot 21 is brought into correspondence with the slots 15 and 37 of the body 14 and of the slide 29, which allows the introduction and the establishment of the tube 4 to be bent, initially straight. The tube 4 is blocked in translation and in rotation along the axis 5 by the central clamp 3. In the event that the tube 4 must undergo, on either side of its central region, several operations of bending, the carriages 8 and 9 with the respective bending heads 11 and 13 are first positioned towards the ends of the bench 1. These carriages 8 and 9 are brought closer to the central clamp 3, as and when executed elbows on the tube 4 by their respective bending heads 11 and 13. We will now describe the progress of a particular bending operation, carried out by the bending head 11:

The position of the elbow to be produced being predetermined, the carriage 8 is first moved in translation along the guide columns 6, by switching on the geared motor 10, so as to bring the bending head 11 onto the point of the tube 4 where this elbow must be executed. The bending plane also being predetermined, the gear motor 20 is then actuated so as to rotate the central shaft 16, by means of the bevel gears 17 and 19. The assembly formed by the pinion 24, the arm 25 and the two rollers 26 and 27 is thus brought into the desired bending plane. it should be noted that the pusher 31 is rotated about the horizontal axis 5 with the shaft 16; in this movement, the head 32 of the pusher 31 describes a circular movement, along the annular groove 30 of the slide 29.

Then the gear motor 36 is actuated, so as to move the slider 29 in translation in the direction of the arrow 38 (FIG. 2), via the pinion 35 and the rack 34. The slider 29 presses on the pusher 31, which is also moved in translation parallel to the axis 5. The rack 33 of the pusher 31 rotates the pinion 24, therefore the arm 25, in the direction indicated by the arrow 39. The bending roller 26, carried by the free end of the arm 25, wraps the tube 4 around the forming roller 27, which performs the bending. The stroke of the slider 29 is predetermined and defines the angle of rotation of the arm 25, therefore the bending angle of the tube 4. After the bending has been carried out, the slider 29 is brought back and the bending roller 26 returns to its position initial.

While the first bending head 11 thus realizes an elbow on the left half of the tube 4, the second bending head 13 realizes according to the same process an elbow at a point on the right half of the tube 4. The positioning and the control of this second bending head are provided by the geared motor 12 already mentioned, as well as by two other geared motors 40 and 41 (see FIG. 1), which correspond respectively to the geared motors 20 and 36 of the first bending head 11 . The elbow executed by the second bending head 13 on the right half of the tube 4 can be produced in a bending plane which is different from the bending plane of the elbow executed on the left half by the first bending head 11.

The following elbows are always produced according to the same process, after having moved in translation the two carriages 8 and 9, therefore the two bending heads 11 and 13, the bending planes being able to be modified at each operation.

When all the desired bends have been made on the tube 4, the respective slots 15, 21 and 37 of the body 14, of the shaft 16 and of the slider 29 are again brought into correspondence, on the two bending heads 11 and 13 , to allow the withdrawal of the bent tube 4, after loosening of the central clamp 3.

The entire operation of the bending machine can be programmed.

In addition to the possibilities for selecting the bending planes on the two bending heads 11 and 13, provision may be made for the central clamp 3 to be orientable by, for example, 90 ° around the axis 5, to avoid contact with the tube 4 during bending with the ground or with any other obstacle, depending on the environment of the bending machine.

Figure 5 shows a rotating bending head 11ʹ whose design is similar to that of the previous figures; the elements of Figure 5 corresponding to those of Figures 2 to 4 are designated by the same references, and will not give rise to a new full description.

In fact, FIG. 5 relates to a variant intended for a machine for bending tubes with a single head. This variant differs from the previous embodiment by eliminating the longitudinal slots in the body 15, the central shaft 16 and the slider 29, which is clear when comparing the hatched areas of Figures 2 and 5, additional hatching appearing in FIG. 5 in place of the slots 15, 21 and 37 in FIG. 2.

Thus, the body 15, the central shaft 16 and the slide 29 of this bending head 11ʹ are entirely tubular coaxial parts, traversed along their common horizontal axis 5 by the tube 4 to be bent. The body 14 of the bending head can here be fixed directly to the frame, not shown, of the bending machine. The bending tube 4, held by a clamp itself carried by a mobile carriage on the frame, is positioned and moved relative to the bending head 11ʹ by the movements of said carriage. The rotation of the central shaft 16 controlled by the geared motor 20 determines, for each bending operation of the tube 4, the orientation of the bending plane.

Figures 6 to 9 show another embodiment of the rotating head 11ʺ, which is similar to the first embodiment described in that it applies to machines for bending tubes with two bending heads, but which differs from it by a more compact construction, its length (dimension along axis 5) being notably reduced.

The bending head 11ʺ therefore also includes a body 14 of cylindrical shape and horizontal axis 5, split longitudinally, the sectional view of FIG. 7 passing through the longitudinal slot 15 of the body 14, provided to allow the passage of the tube 4 to be bent.

Inside the body 14 is rotatably mounted, along the axis 5, a central shaft 16 which is integral with an enlarged portion or rotor 18 fitting into the body 14. The central shaft 16 and the rotor 18 which is integral with it, also, has a longitudinal slot 21. The end of this central shaft 16 remote from the rotor 18 is mounted to rotate, and retained axially, in a split split in two parts 42, fixed to the body 14.

The rotation control of the shaft 16 and of the rotor 18 is here ensured by means of a tangent screw 43, engaged with a circular toothing 44 formed hollow on the cylindrical lateral surface of the rotor 18. As shown in particular Figure 9, the tangent screw 43 is located on the side diametrically opposite to the slot 15; it has its axis oriented in a direction orthogonal to the general axis 5 of the bending head, and it is carried by a shaft 45 mounted to rotate, by means of combined needle and ball thrust bearings 46, in two flanges 47 fixed to the body 14. The rotation drive of the shaft 45, controlling the rotation of the rotor 18, is achievable from a motor not shown, which can be located at a distance from the bending head 11ʺ .

As in the previous embodiments, the enlarged part or rotor 18 is extended, outside the body 14, by a lug 22 on which is rotatably mounted, around an axis 23, an assembly comprising a shafted pinion 24 , a radial arm 25 and a bending roller 26 rotating on an axis 48, while a forming roller 27 is mounted along the axis 23. The tube 4 to be bent passes between the two rollers 26 and 27, and it s' wraps around the forming roller 27 - see in particular Figure 9.

In the annular space 28 located between the body 14 and the shaft 16, is housed as previously a cylindrical slide 29 with a longitudinal slot 37 and with an annular groove 30; a pusher 31, slidingly passing through the rotor 18, has a head 32 introduced into the groove 30, and comprises a rack 33 engaged with the pinion 24. Finally, the slider 29 is provided laterally with a rack 34 engaged with a drive pinion 35, carried by a shaft 49 connected to a motor not shown, which can be located at a distance from the bending head 11ʺ.

The operating principle of this head 11ʺ is identical to that of the previous ones, only the mode of driving the rotor 18 in rotation being different. It is understood that the position here chosen by the means for driving the rotor 18 in rotation makes it possible to substantially reduce the length of the bending head 11ʺ, and it can also be seen that in this latter embodiment all the pinions can be spur gears.

Furthermore, it is understood that, in the case of bending heads as described above applied to machines for bending tubes with two heads (according to Figure 1), the elbows produced on the tube can be all the closer together the bending heads are short. From this point of view, the embodiment of Figures 6 to 9 proves to be particularly advantageous.

Claims (11)

1. Rotating bending head, intended to equip a machine for bending tubes, or other similar elongated objects, the rotation of this head about the axis (5) of the tube to bend (4) determining the orientation of the plane of bending relative to said tube (4), characterized in that it essentially comprises, in combination:
- a tubular body (14) with a horizontal axis (5), coincident with the axis (5) of the tube to be bent (4) and immobilized in rotation,
- a central shaft (16) mounted rotating in the body (14) around the axis (5) of the latter, and comprising an enlarged front part (18) supporting bending tools (26,27), placed in front said body (14),
control means (17, 19, 20; 43 to 47) provided for modifying the angular position of the central shaft (16), therefore the orientation of the bending plane, and
- other control means (29 to 37) for actuating the bending tools (26, 27), these other control means comprising at least one control member (29, 31) mounted to slide parallel to the axis (5) of the bending head (11,11ʹ, 11ʺ), between the tubular body (14) and the central shaft (16) thereof. 2. rotating bending head according to claim 1, characterized in that the central shaft (16) comprises, at one end, a conical drive pinion (17), while a gear motor (20) is coupled to another bevel gear (19) engaged with the previous one, to control the rotary movement of the central shaft (16). 3. rotating bending head according to claim 1, characterized in that the enlarged part (18) of the central shaft (16) has at its periphery a circular toothing (44) engaged with a tangent screw (43), d axis orthogonal to that (5) of the bending head (11ʺ), which is coupled to a drive motor, to control the rotary movement of the central shaft (16). 4. rotating bending head according to any one of claims 1 to 3, characterized in that the enlarged part (18) of the central shaft (16) is extended by a tab (22) which extends to the outside of the tubular body (14) and which supports the bending tools, comprising on the one hand a bending roller (26) mounted at the free end of an arm (25) itself mounted rotatably on the tab (22 ), around an axis (23) orthogonal to the horizontal axis (5) of the tubular body (14), and on the other hand a forming roller (27) mounted along the same axis (23) as the arm (25). 5. rotating bending head according to claim 4, characterized in that the control means for actuating the bending tools (26,27) comprise a slide (29) with longitudinal slot (37) movable in translation to the inside the tubular body (14) along the axis (5) of the latter, and a pusher (31) eccentric with respect to the central shaft (16) and having one end (32) connected to the slide (29), while that are other end (33) is linked to the arm (25) carrying the bending roller (26), the connection between the pusher (31) and the slide (29) allowing rotation of the pusher (31) relative to the slide ( 29). 6. rotating bending head according to claim 5, characterized in that the pusher (31) slidably passes through the enlarged part (18) of the central shaft (16). 7. rotating bending head according to claim 5 or 6, characterized in that one end of the pusher (31) forms an enlarged head (32), introduced into an annular groove (30) of the slide (29). 8. rotating bending head according to any one of claims 5 to 7, characterized in that the pusher (31) comprises, towards its other end, a rack (33) engaging a pinion (24) which is integral of the arm (25) on which the bending roller (26) is mounted. 9. rotating bending head according to any one of claims 5 to 8, characterized in that the slide (29) itself comprises, laterally, a rack (34) which engages with a drive pinion (35 ), coupled to a gear motor (36). 10. rotating bending head according to any one of claims 5 to 9, characterized in that it is intended to equip a machine for bending tubes with a single head (11ʹ), its coaxial bodies that are the body (14) , the shaft (16) with its enlarged part (18) and the slide (29) being fully tubular shaping members. 11. rotating bending head according to any one of claims 5 to 9, characterized in that it is intended to equip a machine for bending tubes with two bending heads (11,13), longitudinal slots (15, 21,37) being provided respectively on the body (14) of this bending head (11,11ʺ), on the central shaft (16) with enlarged part (18), and on the slide (29) used for the control bending tools (26,27).

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