EP1311356B1 - Tube bending machine - Google Patents

Abstract

A machine for high rate serial bending of a tube includes a bending head provided with a radius block and a backing block including, at the periphery, a groove with a semicircular cross-section and a driver for the backing block in rotation coaxial to the radius block, so as to drive the tube to be bent and wind it on the radius block. The radius block includes a disc including a beveled panel arranged along a chord of the disc and it includes device for moving the bending head relative to the axis of the tube along a path passing through the pins of the radius block and the backing block and a device for axially rotating the radius block independently from the displacement of the backing block.

Description

The present invention relates to a machine for bending of tubes in series and at high rate.

We already know many devices for arching, or bend, tubes, which consist for the most part of hand tools, electrically operated or not, in particular used by building professionals to bend copper tubes for the installation of installations health.

These devices have a shape having the radius of desired curvature, and a counterform capable of being displaced coaxially with said shape, on the periphery thereof, in driving the tube to be bent which is wedged between said form and said counter-form, so as to wind it on said form.

A tube can not be arched or bent in the same way as is a wire, because because of its axial channel, a tube risk to be crushed. Also, form and counter-form comprise each a groove of cross section in a circular arc of radius of curvature corresponding to the diameter of the tube to be arched.

In general, the counterform is in the form of a movable block in a limited pivoting manner, and in which is performed longitudinally the throat, or a grooved roller mounted in free rotation. The bending operation is made while the tube is in contact with the funds of two throats.

Note that the throats are enveloping, that is to say depths with a maximum depth equal to the radius of the tube at arch, and less said tube may be crushed.

The tube is thus retained laterally by the grooves of the form and counter-form, so that to disengage it side of the tool, to remove it or to perform a second camber in another direction, the tool is equipped with means to distance the form from the counterform. These means allow the replacement of the form by a other of a different radius of curvature and / or adapted to a tube of another diameter.

To allow the disengagement of the tube, it is planned on benders to use shapes having a cutaway in sort of allow to disengage the tube from the throat of the against form. This is the case, for example, with the document machine GB 1,298,666, which is intended to bend U-shaped tubes into simultaneously making two folds at right angles each on a against form. It should be noted that to allow disengagement tube, the two cons-forms each comprise two sections cut.

It should also be noted that the machine that is the subject of this document is not not for the same purpose as that of the present invention and that in no case it can not achieve the same folds.

Indeed, the present invention relates more particularly machines that allow the bending of tubes in series and at a high rate, these tubes being notably intended for the production of frames. These machines include a means for feeding the tube which supplies a bending head equipped with movable bending tools with respect to other.

These machines are, however, more particularly intended for to bend wire, too, the bending obtained is not always of excellent quality, the tube being in most cases slightly crushed at its bent part or parts.

Moreover, on this type of machine, move the shape by relative to the counter-form to allow lateral clearance tube is a waste of time which is detrimental to the productivity.

In addition, the use of machines of this type is limited, these do not allow for example to arch a tube to 180 ° then disengage it in order to remove it or to perform a bending in another direction.

Note that it is often necessary to make a tube two or more cambrings of different directions, which is obtained by disengaging the tube and then repositioning after having made it operate an axial pivoting. On a machine as mentioned above, the axial pivoting of the tube is relative, it is indeed the bending head that rotates around the axis of the tube; if there is no possibility of Lateral disengagement, moreover during a 180 ° bending, said pivoting is impossible.

The present invention aims to remedy the various disadvantages mentioned above, by proposing a machine for bending of a tube, which authorizes working cadences high, and which allows in particular to arch a tube at 180 °, without risk of crushing the tube.

The machine for bending a tube in series and at a rate high according to the invention comprises a bending head comprising a form and a counter-form which comprise in periphery a groove of semicircular section, as well as means for driving said counterform in rotation coaxially with said shape so as to cause the tube to arching and winding it on said shape, and it is characterized essentially in that said form consists of a disk having a cutaway disposed along a rope of said disk, and in that it includes means for moving said bending head relative to the axis of the tube, according to a trajectory passing through the axes of said form and counter-form, as well as means for rotating axially said shape, regardless of the displacement of said counterform.

By positioning the cutaway of the shape, to the right of the counter-form, and by the displacement of the bending head, and so of the form and against-form with respect to the axis of the tube, it is possible to release the cambered tube laterally, in providing for a cut-off of adequate size, that is to say when the distance between the cutaway and the edge of the counterform is at least equal to the diameter of said tube.

According to an additional feature of the machine according to the invention, the means for moving the head of bending with respect to the tube, drive it according to a rectilinear trajectory.

According to another additional feature of the machine according to the invention, the means for moving said head of bending relative to the tube cause it to Curved trajectory.

According to another additional feature of the machine according to the invention, the counterform consists of a roller.

According to another additional feature of the machine according to the invention, the counterform consists of a pressing block.

According to another additional feature of the machine according to the invention, the means for moving the head of bending in relation to the tube, and the means to make axially rotate the form, consist of stepper motors digitally controlled.

According to a preferred embodiment of the machine according to the invention, the bending head is carried by a movable arm in pivoting, on which it is movable pivotally coaxially with the form, the latter being mounted mobile in axial pivoting on said bending head.

The advantages and characteristics of the machine according to invention, will become clearer from the description which follows and which refers to the annexed drawing, which represents a non-limiting embodiment.

• la figure 1 représente une vue schématique partielle d'une machine pour le cambrage de tubes.
• les figures 2a, 2b, 2c et 2d représentent des vues schématiques partielles de la même machine lors de phases successives différentes d'une opération de cambrage.

In the attached drawing:

• FIG. 1 represents a partial schematic view of a machine for bending tubes.
• Figures 2a, 2b, 2c and 2d show partial schematic views of the same machine in successive phases different from a bending operation.

FIG. 1 represents the bending head 1 of a machine according to the invention, on which is placed a tube 2 maintained by a feeding means, not shown, which consists of a element able to hold the tube 2 and to drive it axially in one sense as in the other as the materializes the double X arrow.

The bending head 1 has a shape 3 and a counter form 4, between which passes the tube 2.

The shape 3 consists of a disc having a cutaway 30 disposed along a rope, while its curved edge 31 comprises a groove 32, which is represented by transparency only the bottom 33, of semicircular cross-section of radius equal to that of the tube 2.

Counterform 4 consists of a roller mounted crazy on a tree 40, and which has on the periphery a groove 41, of which is represented by transparency as the bottom 42, section transverse semicircular also of the same radius as that of the tube 2.

The form 3 is rotatably mounted on the bending head 1 by via a shaft 34 adapted to be rotated by motor means, not shown, so as to rotate the shape 3 axially relative to the bending head 1, in one way or the other, according to the double arrow Y.

The bending head 1 is carried by an arm, not shown, on which it can, by means of motor means, also not shown, pivot coaxially with the axis of rotation of the form 3, in one direction or the other, according to the double arrow Z.

On the other hand, the arm, not shown, which carries the head of bending 1, is movable relative to the tube of the feeding means 2, so that it describes a trajectory through the trees 34 and 40. In the illustrated embodiment, this trajectory, which is materialized by the double arrow R, is curve, it results from the pivoting of the arm. It will be noted that this trajectory can be, preferably, rectilinear, which can however, make the construction of the machine more complex.

The dimensions of form 3 and counterform 4, their spacing, as well as the height of the rope according to which is realized the cut cut 30, are such that when the cut 30 is at the right of the counter form 4, it remains between the form 3 and the counter-form 4 a space at least equal to the diameter of the tube 2.

Referring now to FIGS. 2a, 2b, 2c and 2d, one can see different phases of a bending operation of the tube 2, knowing that Figure 1 represents a preliminary phase where the pan cut 30 is at the right of the counter-form 4 and the head of bending 1 is positioned so that the tube 2 comes to cutaway contact 30.

For the sake of clarity, the different directions of rotation Y, Z and R will be assigned an index A or B according to whether they coincide with, respectively, clockwise or counter-clockwise.

In FIG. 2a, by a movement of the bending head 1 in the direction R _B , the bottom 42 of the groove 41 of the counterform 4 is brought into contact with the tube 2.

The following phase, represented in FIG. 2b, consists in rotating the shape 3 according to Y _A so that the tube 2, which is in the locking position in the axial direction, is engaged in the groove 32 and then blocks the shape 3 in this position with respect to the bending head 1.

The tube 2 is thus sandwiched between the form 3 and the counterform 4, in the throats thereof respectively 32 and 41. The grooves 32 and 41 are preferably semicircular, and of a diameter equal to that of the tube 2, so that it operates a close contact between the tube 2 and the bottoms 33 and 42 of the grooves, respectively 32 and 41.

In this case, the depth of the grooves 32 and 41 is equal to radius of the tube 2, and the height of the rope according to which is realized the cut 30 is equal to the diameter of the tube.

Referring now to FIG. 2c, it can be seen that the rotation of the bending head 1 in the direction Z _B causes the counterform 4 to rotate coaxially with the shape 3, which remains in the position taken during the phase previous. The displacement of the counterform 4 around the shape 3 results in the winding of the tube 2 on the latter.

The relative immobility of the form 3 is obtained from different ways according to the architecture of the bending head 1.

Thus, if the motor means which cause the shape 3 are carried by the bending head 1, the rotation in the direction Z _B must be accompanied by a counter-rotating compensation of the shape 3 in the direction Y _A.

On the other hand, if the counter-form 4 is mounted in rotation on the shaft 34 which bears the form 3, the latter can be maintained fixed during the displacement of the counterform 4.

Note that in a variant, it is possible to bend the tube 2 by immobilizing it on the form 3 via the counterform 4, which in this case may not be a roller but a locking means such as a pressure block for example, and combining on the one hand a rotation of the bending head 1 according to Z _B synchronized to a rotation along Y _B of the form 3 having previously rotated along Y _A to not not winding the tube 2 on the cutaway 30, and secondly a proportional advance movement of the tube 2 according to X.

This variant makes it possible to arch a tube nearby end, or near a camber or discharge.

Referring now to Figure 2d, it can be seen that, after the bending of the tube 2, the latter is moved axially, the counterform 4 has been returned to its starting position by a rotation in the direction Z _A , the shape 3 has turned in the direction Y _B to bring the cut face 30 parallel to the tube 2, and the bending head 1 has been moved in the direction R _A so that the cut 30 comes into contact with the tube 2 and that it sort of the groove 41, so that the tube 2 can, after cutting, be released laterally.

Claims (7)

1. Machine for bending a tube in series and at a high rhythm, including a bending head (1) comprising a mould (3) and a counter-mould (4) which comprise at the periphery a groove (31, 41) with a semicircular cross-section, as well as means allowing to cause said counter-mould (4) to rotate co-axially to said mould (3), so as to drive the tube to be bent (2) and to wind it up onto said mould (3), characterised in that said mould (3) consists of a disc having a cut-off comer (30) arranged according to a chord of said disc, and in that it includes means allowing to move said bending head (1) with respect to the axis of the tube (2), according to a path (R) passing through the axes (34, 40) of said mould (3) and counter-mould (4), as well as means allowing to cause said mould (3) to rotate axially, independently from the displacement of said counter-mould (4).
2. Machine according to claim 1, characterised in that the means allowing to move said bending head (1) with respect to the tube (2) drive the latter according to a rectilinear path.
3. Machine according to claim 1, characterised in that the means allowing to move said bending head (1) with respect to the tube (2) drive the latter according to a curved path (R).
4. Machine according to any of the preceding claims, characterised in that the counter-mould (4) consists of a roller.
5. Machine according to any of the preceding claims, characterised in that the counter-mould consists of a pressing block.
6. Machine according to any of the preceding claims, characterised in that the means allowing to move said bending head (1) with respect to the tube (2) and the means allowing to cause the mould (3) to rotate axially consist of numerically controlled stepping motors.
7. Machine according to any of claims 1, 3, 4 and 5, characterised in that the bending head (1) is carried by a pivotal arm on which it is pivotally movable co-axially to the mould (3), the latter being pivotally and axially mounted on said bending head (1).

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