EP1313577B1 - Wire bending device - Google Patents

Abstract

The invention concerns a wire bending device comprising a bending head (3) bearing two bending tools (30, 31) between which the wire to be bent (2) is passed, each of the tools being capable of being driven in rotation concentrically around the other which is then fixed It comprises: mechanical means (1) for moving the wire to be bent (2) axially in one direction or another (XA, XB); mechanical mans for driving the tools (30, 31) in rotation, in the two directions (YA, YB), about an axis (34) parallel to those (32, 33) of the tools (30, 31); mechanical means for moving in the two directions (ZA, ZB) the tools (30, 31) in a plane perpendicular to the axis (34) about which the latter can rotate; and calculating and controlling means for managing simultaneously the operation of the mechanical means so that the movements generated by the latter are superimposed.

Description

The present invention relates to a wire bending device, as for example known from document DE-A-34 21 338.

To date, there are two main categories of wire bending machines, those used for large series which include bending tools placed in a position corresponding to the profile to be given to the metal wire, and those used for small series, which allow you to move from one profile to another without, unlike the previous ones, changing tools.

The machines of this second category all implement the same bending process which consists in passing the wire between two bending tools, one of which is fixed and the other movable in rotation concentrically to that which is fixed.

In practice, the wire from a spool or a boot passes through a straightener, then is supported by a feeding system which brings the desired length to a bending head, which is generally mobile in rotation around of the axis of the wire, and comprises a fixed finger for holding the wire and a camber roller capable of rotating concentrically with said finger in order to camber the wire.

The change of direction of curvature is obtained by modifying the starting position of the finger and the roller, the positions of which are reversed with respect to the wire, which is achieved by axial rotation around the wire or, when said rotation is not possible , by displacement after their retraction in the head.

These numerically controlled machines are very flexible to use, and allow the production of series of parts ranging from a few tens to several thousand.

Victims of their success, they are used for larger series because with experience, their programming becomes easy.

However, for large series, we quickly notice their slowness, due to the retraction time of the roller and the finger which represents about 40% of the total time of a bending operation.

To overcome this drawback, it has been proposed, in particular in document FR 2,744,941, to pass the wire to be bent between two rollers each capable of being driven in rotation concentrically around the other which is then fixed.

This process avoids the retraction phases of the bending roller, since the two rollers can at will alternately become bending roller or fixed finger for holding the wire.

To implement this method, a device is proposed in this document comprising, in a bending head movable in rotation about the axis of the wire, on the one hand two parallel shafts, between which passes transversely, externally to said head. bending, the wire to be bent, said shafts being connected by means of a part comprising two identical toothed wheels secured to one another not coaxially by their sides, said shafts each passing axially and integrally through one of said wheels gear; on the other hand, for each of said shafts, a guide path in an arc, the guide path of one shaft being coaxial with the other shaft; and on the other hand, a toothed wheel driven in rotation in one direction or the other, positioned in the region opposite the concave parts of said guide tracks and so as to mesh with said toothed wheels.

This device is relatively complex and has the drawback of being unreliable over time.

This lack of reliability is increased by the fact that the driving of the shafts in the guide tracks is carried out by means of sliding shoes, which are faced with wear problems.

The present invention aims to remedy this drawback by proposing a bending device operating according to the same method, and which is of a more robust design and therefore more reliable.

• une tête de cambrage portant deux outils de cambrage entre lesquels passe le fil à cambrer, du type où chacun desdits outils est susceptible d'être mené en rotation concentriquement autour de l'autre qui alors est fixe,
• des moyens mécaniques aptes à entraîner lesdits outils de cambrage en rotation, dans les deux sens, autour d'un axe parallèle à ceux desdits outils,
• des moyens mécaniques aptes à déplacer dans les deux sens lesdits outils dans un plan perpendiculaire à l'axe autour duquel ceux-ci peuvent tourner,

et il se caractérise essentiellement en ce qu'il comporte aussi :

• des moyens mécaniques aptes à déplacer le fil à cambrer axialement dans un sens ou dans un autre,
• et des moyens de calcul et de commande aptes à gérer le fonctionnement en simultané desdits moyens mécaniques de manière à obtenir une superposition des mouvements que ceux-ci génèrent.

The wire bending device which is the subject of the present invention comprises:

• a bending head carrying two bending tools between which the wire to be bent passes, of the type where each of said tools is capable of being driven in rotation concentrically around the other which is then fixed,
• mechanical means capable of driving said bending tools in rotation, in both directions, about an axis parallel to those of said tools,
• mechanical means capable of moving said tools in two directions in a plane perpendicular to the axis around which they can rotate,

and it is essentially characterized in that it also includes:

• mechanical means able to move the wire to be bent axially in one direction or another,
• and calculation and control means able to manage the simultaneous operation of said mechanical means so as to obtain a superposition of the movements that these generate.

The superposition of the movements generated by the various mechanical means makes it possible to achieve in a relative manner the positioning and the immobilization of one of the tools relative to the wire to be bent while rotating the other tool concentrically with said immobilized tool.

According to an additional characteristic of the device according to the invention, the axis around which the tools can rotate is arranged at the intersection of the axis of movement of the wire to be bent and a line joining the axes of the tools.

According to another additional characteristic of the device according to the invention, the bending tools consist of rollers.

According to another additional characteristic of the device according to the invention, the mechanical means consist of stepping motors associated with transmission means.

According to a particular embodiment of the device according to the invention, the bending head is rotatably mounted on an arm, itself pivotally mounted relative to a means for feeding the wire to be bent.

The advantages and characteristics of the device according to the invention will emerge more clearly from the description which follows and which relates to the appended drawing, which represents a non-limiting embodiment thereof.

In the attached drawing:

Figure 1 shows a partial schematic view of the bending device according to the invention.

Figures 2a, 2b and 2c show partial schematic views of the same device during different phases of a bending operation.

With reference to FIG. 1, one can schematically see a bending device according to the invention, which comprises a means 1 for supplying a bending wire 2 and a bending head 3.

The feed means 1 is able, under the action of motor means not shown, to drive the wire 2 axially, in the direction of the bending head 3, arrow X _A , or in the opposite direction, an arrow X _B.

The bending head 3 comprises two bending tools, in this case two rollers 30 and 31 mounted in free pivoting on shafts 32 and 33 respectively, and between which the wire to be bent 2 passes.

The bending head is movable in rotation about an axis 34, parallel to the shafts 32 and 33 and, in this particular embodiment, located in the middle of the segment which joins the latter, this rotation being able to be carried out clockwise , arrow Y _A , or in the opposite direction, arrow Y _B.

In addition, the bending head 3 is pivotally movable relative to the feed means 1, so as to describe a trajectory in the shape of an arc of a circle, clockwise, arrow Z _A , or in the opposite direction, arrow Z _B.

Note that it is also possible for the displacement of the bending head 3 to be carried out in a rectilinear manner. This variant has advantages from the programming point of view of the calculation and control means, on the other hand it is of more complex construction.

The various movements are carried out by means of mechanical means, not shown, such as for example stepping motors associated with transmission means, the operation of which is managed simultaneously by calculation and control means allowing overlapping. of these movements.

The superposition of these movements makes it possible to immobilize the roller 30 or the roller 31 relative to the wire to be bent 2, while rotating around the immobilized roller 30 or 31, the roller, respectively 31 or 30, which drives and bends the wire 2.

The strict superposition of the movements according to Y _A , Y _B , Z _A and Z _B , allows the rotation of one of the rollers around the other which is positioned on an axis parallel to the wire 2 without however remaining stationary. Immobilization is therefore obtained in a relative manner by the displacement of the wire 2 along X _A and X _B , which makes it possible to cancel the displacement of the rollers.

With reference to FIG. 2a, it can be seen that during bending of the wire 2 in the counterclockwise direction, the roller 30 remains stationary, while roller 31 rotates concentrically with the roller 30 according to an arrow B, to camber the wire 2.

The movement along arrow B is obtained, starting from a starting position such as that shown in FIG. 1, by the superposition of a movement along Y _B and Z _B , as well as, successively, movements along X _B and X _A.

The backward and forward movement of the wire 2 along X _B and X _A is necessary because in the bending operation shown, the folding angle is greater than 90 °.

In FIG. 2b, the bending head 3 is returned to the starting position, while the wire 2 advances along X _A in order to carry out another bending operation.

Referring now to Figure 2c, we can see a bending operation of the wire 2 clockwise, so relatively, the roller 31 remains stationary, while roller 30 rotates concentrically with the roller 31 in an arrow A, to camber wire 2.

The movement along arrow A is obtained by superimposing a movement along Y _A and Z _A , as well as, successively, movements along X _B and X _A.

In the same way as for the bending operation represented in FIG. 2a, the movement of retreat and advance of the wire 2 according to X _B and X _A is required by the fact that the folding angle is greater than 90 ° .

The bending device according to the invention allows wire bending to be carried out. Such a bending device uses proven mechanical means, which therefore have high reliability.

Claims (5)

1. Wire-bending device, including :

   - a bending head carrying two bending tools, between which passes the wire to be bent, of the type in which each of said tools is capable of being rotationally mounted concentrically about the other one, which is then fixed,

   - mechanical means capable of driving said bending tools (30, 31) in rotation in both directions (Y_A, Y_B) about an axis (34) parallel to those (32, 33) of said tools (30, 31),

   - mechanical means capable of moving, in both directions (Z_A, Z_B), said tools (30, 31) in a plane perpendicular to the axis (34) about which they can rotate,

      characterised in that it also includes :

   - mechanical means (1) capable of axially moving the wire to be bent in one direction or in the other direction (X_A, X_B),

   - and calculating and control means capable of controlling the simultaneous operation of said mechanical means, so as to achieve a superposition of the motions they generate.
2. Device according to claim 1, characterised in that the axis (34) about which the tools (30,31) can rotate is arranged at the intersection of the axis of displacement of the wire to be bent (2) and a line connecting the axes of the tools (32, 33).
3. Device according to claim 1 or claim 2, characterised in that the bending tools consist of rollers (30, 31).
4. Device according to any of the preceding claims, characterised in that the mechanical means consist of step motors associated with transmission means.
5. Device according to any of the preceding claims, characterised in that the bending head (3) is rotationally mounted on an arm that is, in turn, pivotally mounted with respect to means (1) for supplying the wire to be bent (2).