EP0442835A1 - Method and device for forming wire bobbins - Google Patents

Abstract

According to this method, preformed turns (10) of the said wire are dropped into a forming pit (1) which has a substantially cylindrical wall with a vertical axis, where they are superposed in order to form a bobbin (7). As the turns (10) fall, a radial force of attraction towards the wall of the pit (1) is exerted on them, the direction of this force being stimulated by a movement of rotation about the axis of the pit. The attraction force is preferably generated by a rotating magnetic field. To this end, the device comprises means for exerting, on the turns (10), the said force stimulated by a rotational movement comprising inductors, such as electromagnets (5), uniformly distributed at the periphery of the pit and means for cyclically supplying these electromagnets with direct current. <??>The invention applies to the forming of wire bobbins in magnetic metal, particularly steel. <IMAGE>

Description

The present invention relates to a method and a device for forming a coil of metal wire, in particular steel, of the type according to which preformed turns of said wire are dropped in a formation well, having a cylindrical wall with a vertical axis, and of internal diameter greater than the diameter of the turns and in which said turns accumulate to form the coil.

Devices of this type are notably used in installations for rolling metal wires to form coils which are then compacted and tied. In such installations, after rolling, the wire is preformed into turns which are then arranged substantially flat and overlapping one on the other on a generally provided cooling conveyor, during the displacement of which the wire turns are cooled.

At the end of the conveyor, the wire turns fall one after the other in a well with a cylindrical wall and a vertical axis, of diameter slightly greater than that of the turns, where they stack to form a coil which is then extracted from the well to be compacted and bound before storage or use.

Such an installation is described in particular in documents FR-A-1 383 950; FR-A-2 057 934 and FR-A-2 105 309.

In such installations, the turns, although partially guided by an axial warhead placed inside the well, tend to deposit one on top of the other in a disorderly manner. It follows that the height of the coil thus formed is much greater than if the turns were well ordered.

As mentioned above, the coils are then compacted, by exerting an axial pressure on them. The turns being arranged in a disorderly manner, the wires cross in many places, and during compaction wire the risk of injury at these crossings is important.

The object of the present invention is to solve these problems and to propose a system for forming a coil which makes it possible to order the arrangement of the turns, to reduce the size of the coils and to avoid injuries to the wire.

With these objectives in view, the invention relates to a method of forming coils of wire of the type indicated at the beginning of this thesis, this method being characterized in that during the fall of the turns in the well, one exercises on these a radial force of attraction of the turns towards the wall of the well, the direction of this force being animated by a rotational movement around the axis of the well.

The invention also relates to a device for forming coils of metal wire previously shaped into turns, comprising a well for forming the coil having a cylindrical wall with a vertical axis. According to the invention, the device is characterized in that it comprises means for exerting on said turns a centrifugal radial force animated by a rotational movement around the axis of the well.

As will no doubt have already been understood, the method and the device according to the invention make it possible to order the arrangement of the turns in the coil being formed, so that they are arranged in superimposed layers, the turns of each layer being angularly offset from each other. In other words, each turn, or group of turns, is substantially in contact with the wall of the well at a point and the respective contact points of two successive turns, or groups of turns, are regularly offset circumferentially. The proliferation of turns is thus optimized during the formation of the coils. This results in a substantial gain, at constant wire length, on the height of the coils and therefore on the size thereof. In addition, the turns being regularly arranged in the coils, these hold better and are less likely to deform during handling. Since the coils thus formed are more compact, the subsequent compaction operations can be reduced or even eliminated, which can lead to the elimination of the compactors and therefore to the reduction of the time and cost of manufacture, or at least to the reduction of the risk. wire injury during compaction.

According to a particular arrangement of the invention, the method is applied to the formation of coils of metal wire which can be attracted by a magnet, and the force of attraction of the turns is generated by a rotating magnetic field, this magnetic field preferably being generated by inductors such as electromagnets regularly distributed around the periphery of the formation well and supplied cyclically with direct current.

Thanks to this arrangement, the cyclic attraction of the metal turns towards the wall of the coil formation well can be carried out in a very simple manner without mechanical organs intervening inside the well. The use of a magnetic field generated by electromagnets also makes it possible to easily adjust the intensity of the attraction force as well as the speed of rotation of the rotating field as a function of the diameter of the wire, the dimensions of the turns, and the speed of the conveyor for transporting the turns and also the speed of fall of the turns in the well.

In addition, the use of electromagnets placed outside the well makes it possible to easily adapt the method according to the invention to existing installations, without significant modifications to the well, only the wall of the well at the height of the electromagnets having to be produced in a non-magnetic material.

Other characteristics and advantages of the invention will appear in the description which will be given by way of example of a device and method according to the invention applied to the formation of coils of steel wire at the end of line of a wire rolling train.

• la figure 1 est une représentation schématique en coupe axiale d'un dispositif de formation de bobine conforme à l'invention ;
• la figure 2 est une vue de dessus de ce dispositif ;
• la figure 3 est une autre vue de dessus représentant schématiquement une disposition particulière des électroaimants.

Reference is made to the appended drawings in which:

• Figure 1 is a schematic representation in axial section of a coil forming device according to the invention;
• Figure 2 is a top view of this device;
• Figure 3 is another top view schematically showing a particular arrangement of the electromagnets.

• une virole supérieure 2, dont la partie supérieure peut être légèrement évasée pour former un réceptacle pour des spires de fil 10 qui y sont amenées par le convoyeur 11 entraîné selon la flèche 12 et sur lequel le fil est disposé en spires 10′ sensiblement à plat et en recouvrement partiel ;
• une virole inférieure 3 qui sert de guide et de maintien pour la bobine de fil formée, et est pourvue de moyens non représentés permettant d'extraire la bobine du puits ;
• une virole intermédiaire 4 en matériau amagnétique.

The device shown in Figures 1 and 2 includes a well 1 for forming coils of steel wire whose wall is cylindrical with a vertical axis. This wall includes:

• an upper ferrule 2, the upper part of which can be slightly flared to form a receptacle for turns of wire 10 which are brought there by the conveyor 11 driven according to arrow 12 and on which the wire is arranged in turns 10 ′ substantially flat and in partial recovery;
• a lower ferrule 3 which serves as a guide and support for the spool of wire formed, and is provided with means not shown enabling the spool to be extracted from the well;
• an intermediate ferrule 4 made of non-magnetic material.

Electromagnets 5, five in number in the example shown, are distributed circumferentially at the periphery of the intermediate ferrule 4 on which they are fixed. The height of the electromagnets 5 is slightly less than that of the intermediate ferrule 4, so that substantially all of the lines of the magnetic field created by the electromagnets in operation pass through said intermediate ferrule.

Inside the well 1 there is a horizontal plate 6 movable vertically, its upper position being located at the level of the intermediate ferrule 4. This plate is intended to support the coil 7, and is gradually lowered so that the upper part of the coil being formed remains permanently in the action zone of the field created by the electromagnets 5. In FIG. 1, the device is shown at the start of training, the coil 7 then being formed only by a few turns of the wire 10 deposited on the plate 6 in the high position.

The plate 6 is annular and surrounds a central mandrel 8 which ends upwardly with a warhead 9 intended to provide additional guidance of the turns 10 of wire when they fall into the well 1 and in particular to prevent the turns falling obliquely and disrupt the formation of the coil. The warhead 9 which is located at the level of the intermediate shell 4 is preferably made of non-magnetic material. This warhead is however not essential, in particular when winding large diameter wire, because the implementation of the method according to the invention has the effect of guiding the fall of the turns and of ordering their positioning in the coil. .

According to the arrangement shown in Figure 3, the electromagnets 5 are arranged "horizontally", that is to say so that the general direction of the field lines which extend between the two poles of the same electromagnet is in a horizontal plane. For this purpose the electromagnets can be shaped according to the schematic representation of FIG. 3, the magnetic yoke of these having a U shape and the poles formed by the ends of the branches of the U extend vertically over a height slightly less than that of the non-magnetic ferrule 4 and are attached to the outer surface thereof.

As a variant, it is possible to arrange the electromagnets "vertically", that is to say so that the field lines have a general vertical direction.

The electromagnets 5 and their means for supplying electric current are determined so that the effect on the turns of the field which each electromagnet generates, is essentially located in the part of the annular zone comprised between the intermediate ferrule 4 and the warhead 9 and located opposite said electromagnet.

In other words, the attractive force exerted by an electromagnet on the turn or turns which are at its level when it is supplied with electric current is exerted only on the arc portion of this or these turn closer to said electromagnet.

It is recalled that in this type of installation, the internal diameter of the well is greater than that of the turns. For example, the diameter of the well is 1150 mm and that of the turns about 1050 mm. Each turn therefore has a possible horizontal clearance inside the well of approximately 100 mm. When one of the electromagnets is excited, the coil (s) in the process of falling which are at the height of the intermediate ferrule 4 may therefore be distant from the wall of this ferrule situated opposite said electromagnet by approximately 100 mm, or even more to account for the fact that the turns can be tilted relative to the horizontal. In order for these turns to be subjected to the attraction exerted by this electromagnet it is necessary that the field generated by it penetrates inside the well over a depth at least equal to this distance, that is, in the case exemplified above. , about 150 mm.

It will be readily understood that the depth of penetration of the magnetic field into the well will have to be adapted in particular as a function of the diameters of the well and of the turns, and also as a function of the presence or absence of the warhead and of the diameter thereof. this.

Furthermore, in order to cause the magnetic field to rotate around the axis of the well, the device comprises means, not shown, for cyclically supplying the electromagnets 5 with direct current. These means make it possible to power the electromagnets according to several different cycles. For example, with reference to FIG. 3 where the electromagnets are respectively identified by the letters a, b, c, d, e, it is possible to supply only one electromagnet at a time and carry out a supply cycle in the order a , b , c , d , e , a ... or in the order a, c, e, b, d, a ... It is also possible to simultaneously power two electromagnets, preferably neighbors, for example according to one of the following cycles:

a + b, c + d, e + a, b + c, d + e, ...

a + b, b + c, c + d, d + e, e + a, ...
or a + c, b + d, c + e, d + a, e + b, ...

The direction of rotation can also be reversed.

We will now describe the implementation of the device for the formation of a coil. Before the arrival of the first turns transported by the conveyor 11, the electromagnets 5 are supplied according to one of the previously determined cycles.

The plate 6 is brought into its upper position shown in FIG. 1, at the height of the intermediate shell 4. The first turns 10 fall into the well 1 and fall on the plate 6. It is specified that in the case where the device is adapted to an installation of the type described in the document FR 2 105 309 cited above, and to which reference will be made for possible additional information, the first turns can be deposited on retractable fingers which penetrate into the well and ensure the support of the coil awaiting return to the high position of the plate, these fingers then disappearing to allow the coil during formation to come to rest on the plate.

When they fall, the wire turns are attracted by the electromagnets 5 and, due to the cyclic supply of these which creates a rotation of the magnetic field, the turns are distributed circumferentially in partial overlap as shown in FIG. 2. As the coils are deposited and therefore as the height of the coil is increased, the descent of the plate 6 is controlled so that the upper part of the coil being formed remains at the intermediate shell and thus remains subject to the action of the magnetic field.

Preferably, we will adjust the descent of the platform so to maintain the upper part of the coil near the bottom of the zone of influence of the electromagnets. In this way the field will have a predominant effect on the turns during the fall, the necessary attraction force of said turns then being relatively low. The field will however still have an effect on the turns which have just deposited which will make it possible to avoid the possible displacement of them which could result for example from the elasticity of the turns. The underlying turns being out of the field, however, are not likely to move due to the pressure exerted on them by the upper turns.

When all the turns are removed and the reel formed, the plate is lowered to the low position and the reel is evacuated.

As will be understood, it is thanks to the regular arrangement of the turns that the height of the coil is significantly reduced compared to that of the coils produced according to the prior art, in which the turns were distributed without any regularity. by randomly overlapping.

By way of example, in the case of the installation described above, used downstream of a rolling mill producing wire of diameter 5.5 mm preformed into turns of diameter 1050 mm dropping into the well at a speed of l '' order of 25 turns / second, each electromagnet is supplied with direct current and operates at around 40,000 ampere-turns in the winding. Five electromagnets are used and successively supplied the created field rotating at a speed of about 0.25 revolutions per second.

It was thus possible to obtain a reduction in the height of the coil by more than 30%.

It is specified that the speed of rotation of the field can vary within large proportions, in particular as a function of the electromagnet supply cycle chosen, characteristics dimensions of the wire and the speed of fall of the turns. It also depends on the build-up time of the electromagnets, which implies a minimum supply time for them so that the magnetic field created can produce a sufficient attraction effect on the turns.

In addition, it will be necessary to take into account the remanent magnetization of the electromagnets which causes a delay in the disappearance of the magnetic field relative to the moment of interruption of their electrical supply, it will therefore be necessary to provide a sufficient duration of the supply cycle to prevent the effects of the field created by different electromagnets do not disturb or even cancel each other out.

For this purpose, the electromagnets are preferably placed so that the adjacent poles of two neighboring electromagnets have the same polarity. For the same purpose, it may be preferable to supply the electromagnets according to a cycle in which an electromagnet is then supplied, not the adjacent electromagnet but the next one, and so on.

Likewise, to reduce the response time of the electromagnets, it is possible to permanently maintain in them a certain voltage, for example around 90 V, insufficient to create the attraction effect but making it possible to reduce the rise time. in power during the cyclic supply of these under the working voltage, of the order of 200 V in this case.

The invention is not limited to the device and to the method described above by way of example.

In particular, the number of magnets can be modified and these can be arranged so that the adjacent poles of two adjacent electromagnets are of the same polarity, or of reverse polarity. It will be noted that in the case of adjacent poles of the same polarity, the number of magnets will preferably be even to avoid a discontinuity in the distribution of the poles.

The rotating magnetic field can also be generated by any means known to a person skilled in the art in the field of electromagnetism using for example polyphase inductors or a yoke and windings similar to those of an electric motor stator, supplied with direct current or not.

The magnetic field may also be exerted over a greater or lesser height and at a level more or less close to the upper end of the well, the respective heights of the intermediate or upper ferrules being adapted accordingly.

Claims (12)

1) Method for forming coils of metallic son, in particular of steel, according to which the coils (10) preformed of said wire are dropped into a well (1) of formation having a wall (4) substantially cylindrical with a vertical axis where they are superimposed to form a coil (7), characterized in that during the fall of the turns, a radial force of attraction is exerted on them towards the wall of the well, the direction of this force being driven by a rotational movement around the axis of the well. 2) Method according to claim 1, characterized in that it is applied to metal wire which can be attracted by a magnet and in that said force is generated by a rotating magnetic field. 3) Method according to claim 2 characterized in that said field is generated by electromagnets (5) regularly distributed around the periphery of the well and supplied cyclically with direct current. 4) Method according to claim 3, characterized in that only one electromagnet is supplied at a time. 5) Method according to claim 3, characterized in that two electromagnets, preferably neighboring, are simultaneously supplied. 6) Method according to one of claims 1 to 5, characterized in that said force is exerted at the upper part of the coil during formation. 7) Method according to one of claims 1 to 5, characterized in that said force is exerted on the turns (10) during the fall, above the upper level of the coil during formation. 8) Device for forming coils of metal wire, in particular steel, previously shaped into turns (10), comprising a well (1) for forming the coil (7) having a cylindrical wall with vertical axis, characterized in that it comprises means for exerting on said turns a centrifugal radial force driven by a rotational movement around the axis of the well. 9) Device according to claim 8, characterized in that said force generating means comprise inductors generating a rotating magnetic field. 10) Device according to claim 9, characterized in that said inductors are constituted by electromagnets (5) regularly distributed around the periphery of the well (1) and in that it comprises means for cyclically supplying these electromagnets with direct current. 11) Device according to claim 8, characterized in that the means for exerting the radial force on the turns are placed at a level corresponding to the upper part of the coil during formation and / or above this level. 12) Device according to claim 9, characterized in that the wall of the well at the level of the inductors is made of non-magnetic material.

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