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FIELD OF THE INVENTION

Embodiments of the present invention concern an apparatus for drawing metal wire, which can be used in the field of working metal wire, for example drawing, rolling or stretching, either cold or hot.

The term metal wire is understood to include round pieces, rods, ribbed round pieces, or other filiform metal products with any cross section shape whatsoever.

Embodiments of the present invention also concern a method for drawing metal wire.

BACKGROUND OF THE INVENTION

Plants and processes for drawing or rolling are known, which provide to obtain substantially continuously filiform metal products having a cross section defined on each occasion according to requirements.

Rolling plants or suchlike are normally provided with work stations disposed in sequence, for example a drawing, rolling or yield station or other, through which the wire is made to pass.

Such systems can comprise a drawing apparatus configured to determine the passage of the wire through the stations.

One of the known drawing apparatuses is provided with at least two capstans located adjacent to each other, rotatable around respective axes of rotation, and on which, for a peripheral portion of the two capstans, the wire is wound to define an S-shaped path. The S-shape allows to increase the contact surface of the wire with that of the capstans, thus allowing to ensure a correct drawing action and without sliding.

These types of apparatuses allow to prevent unwanted torsion of the wire. One of the disadvantages of these known solutions is that they require complex and articulated manual operations to introduce the leading end of the wire between the two capstans to define the S-shaped path.

In fact, one of the main problems of these known drawing apparatuses is that, during the initial insertion step of the leading end of the wire, the operator must deform the wire, usually manually, so as to adapt it to the shape of the capstan and determine the passage from one capstan to the next. As well as representing a high risk for the operator, this entails a considerable waste of resources and slows down the production of the plant itself, with costs that are not always permissible for the competitive regime of the sector.

In order to partly obviate this disadvantage, solutions are known in which one of the capstans is mobile peripherally around the other capstan. The rotation of the capstan around the other allows to directly define the S-shaped path.

However, these known solutions are particularly cumbersome and expensive as they require additional actuators to move and control the capstan made to rotate.

There is therefore a need to perfect and make available an apparatus and a method for drawing wire that overcome at least one of the disadvantages of the state of the art.

The present invention also sets itself the purpose of supplying an apparatus for drawing wire that is able to simplify the operations of conveying the latter along the S-shaped path, considerably reducing the operations for manually positioning the wire itself.

It is also a purpose to provide an apparatus of limited size.

It is also a purpose of the present invention to provide an apparatus able to automate the operations of inserting the leading end of the wire which does not require manual intervention by the operator.

The present invention also sets itself the purpose of providing a method for rapidly and correctly drawing wire, minimizing energy consumption and interventions by the operator.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

Embodiments described here concern an apparatus to draw metal wire that comprises at least two capstans located adjacent to each other, rotatable around respective axes of rotation and each provided with a drawing ring for the wire and with a pair of containing elements between which the respective drawing ring is disposed.

In accordance with one aspect of the present invention, each of the containing elements is provided, on its periphery, with at least one housing seating open radially, with respect to the corresponding axes of rotation, toward the outside.

According to the present invention, at least in an angular position of the capstans, the housing seatings of one of the capstans are aligned with those of the other capstan, said drawing apparatus comprising a gripping device configured to hold the wire and positionable in the housing seatings.

This solution allows to introduce and convey the wire automatically along an S -shaped path defined along the periphery of the drawing ring, avoiding the need for an operator to reposition the wire along the path, in particular in the passage section of the latter from one drawing ring to another.

This has the advantage of making the initial positioning of the wire coming from a work station upstream of the drawing apparatus quicker, limiting the manual intervention only to positioning the wire in the gripping device and releasing it in order to be inserted in the work station located downstream.

According to possible solutions, the containing elements of the first capstan are positioned in the space defined between the containing elements of the second capstan, or vice versa.

In accordance with possible solutions, at least two housing seatings provided in the containing elements of each of the capstans are aligned with each other in a direction parallel to the respective axes of rotation of the capstans.

According to possible solutions, the gripping device comprises a support body provided with a vice to hold the wire and with support pins positionable in the housing seatings.

This solution allows to position the gripping device holding the wire in a pair of housing seatings of the containing elements of the first capstan so that the latter, rotating, can convey the wire along the first segment of the S-shaped path. Thanks to the alignment of the housing seatings between the capstans, the present invention allows the wire to pass quickly from the first to the second capstan, without the intervention of the operator.

According to possible solutions, the support pins are coaxial to each other. According to possible embodiments, the support body can be provided with a through cavity defining an axis of insertion for the wire.

The support pins can have their longitudinal axes located transversely to the axis of insertion.

According to possible solutions, the vice comprises sliding guides inclined with respect to the axis of insertion and two jaws positionable along the sliding guides and defining a passage gap in correspondence to their position along the sliding guides.

This configuration allows to define on each occasion the opening of the passage gap in relation to the cross section sizes of the wire.

According to possible solutions, the drawing apparatus comprises a switching device located in the alignment zone, in which the housing seatings of the capstans are aligned with each other, and configured to move the gripping device from the housing seatings of the first capstan to the housing seatings of the second capstan.

In accordance with possible embodiments, the drawing apparatus comprises a plurality of pressing devices disposed on part of the periphery of the drawing rings to keep the wire pressed against the respective drawing rings.

Formulations of the present invention also concern a gripping device of a drawing apparatus of wire as in any embodiment described here.

Formulations of the present invention also concern a method to draw wire that provides to make the wire pass through the first capstan and at least the second capstan of the drawing apparatus as described in any embodiment according to the present invention.

In accordance with one aspect of the present invention, the drawing method provides to:

- attach the wire to a gripping device,

- position the gripping device with the wire attached, in a pair of housing seatings of the first capstan,

- rotate at least the first capstan to wind the wire on part of the respective drawing ring until it reaches the angular position in which the housing seatings of the first capstan are aligned with a pair of housing seatings of the second capstan,

- transfer the gripping device to the pair of housing seatings of the second capstan,

- rotate the second capstan to wind the wire on part of the respective drawing ring of the second capstan.

According to possible embodiments, the method provides to position a switching device in the alignment zone between the housing seatings of the capstans in order to move the gripping device from the housing seatings of the first capstan to those of the second capstan.

According to possible solutions, the method provides to position one or more pressing devices in contact with the wire against the respective drawing rings.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a view from above of a drawing apparatus according to a possible embodiment of the present invention;

- fig. 2 is a perspective view of a gripping device according to a possible embodiment of the present invention;

- fig. 3 is a longitudinal section of fig. 2;

- fig. 4 is a cross section of fig. 2;

- figs. 5-6 are two longitudinal sections of a gripping device in two gripping configurations;

- figs. 7-10 are schematic views of operating sequences of the method according to the present invention;

- fig. 1 1 is a section view along the section line XI-XI of fig. 1.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be incorporated into other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

Embodiments described here, with reference to the attached drawings, concern an apparatus 10 for drawing metal wire 1 1.

For the purposes of illustration, in the drawings the metal wire 1 1 is indicated by a continuous line. The drawing apparatus 10 can be installed in a plant for working filiform metal products between a work station located upstream and a work station located downstream.

In particular, the drawing apparatus 10 allows to draw the wire 1 1 coming from the work station located upstream to the work station located downstream without it rotating on itself.

By way of non-restrictive example, the drawing apparatus 10 can be used to draw metal wires 1 1 having a maximum diameter or cross section size comprised between 2mm and 28mm.

The drawing apparatus 10 comprises at least a first capstan 12 and a second capstan 13 located adjacent to each other and each of which is configured to rotate around respective axes of rotation Rl and R2.

The capstans 12 and 13 can be provided with an actuator, such as a motor, able to make the capstan 12 or 13 to which it is connected rotate.

In particular, it is provided that each actuator is configured to make the two capstans 12 and 13 rotate with the same speed of rotation, in order to prevent sliding of the wire 1 1 or the induction of drawing stresses on the latter.

The wire 1 1 is wound on each of the capstans 12 and 13 for a predefined peripheral portion, that is, a predefined angular amplitude, to define an S -shaped path P. By way of example only, it can be provided that the wire 11 is wound on each capstan 12, 13 for an angle of amplitude comprised between 150° and 210°.

The drawing apparatus 10 can also comprise more than two capstans located adjacent to each other and in this case, not shown, the path P which is defined has an undulating shape.

Each capstan 12 and 13 can comprise at least one drawing ring 14 on which the wire 1 1 is wound.

According to a possible aspect of the invention, the drawing rings 14 of the capstans 12 and 13 have the same diameter.

Each drawing ring 14 can be provided circumferentially with at least one passage groove 15 on which the wire 1 1 is wound.

The passage groove 15 can have a V-shaped cross section to contain and increase the contact surface with the wire 1 1.

Each capstan 12, 13 is also provided with at least one pair of containing elements 16 between which the respective drawing ring 14 is disposed.

In particular, the containing elements 16 protrude radially with respect to the drawing rings 14.

The containing elements 16 can comprise, by way of example, containing flanges 16a having a diameter greater than the diameter of the drawing ring 14 so that the wire 1 1, once inside the containing flanges 16a, remains confined inside the latter.

Each containing element 16 is provided on its periphery with at least one housing seating 17 open radially, that is, in a radial direction with respect to the axes of rotation Rl , R2, toward the outside.

For example, the housing seatings 17 can be defined by eyelets made on the periphery of a containing element 16 for a segment limited to the center of the latter.

The housing seatings 17 of the pair of containing elements 16 of one or the other of the capstans 12 or 13 are advantageously aligned with each other in a direction parallel to the respective axis of rotation Rl or R2 of the capstan.

According to one aspect of the present invention, at least in an angular position of the capstans 12 and 13, the housing seatings 17 of the first capstan 12 aligned, are aligned with the housing seatings 17 of the second capstan 13.

The two capstans 12 and 13 can be positioned angularly so that at least two pairs of housing seatings 17 are aligned with and overlap on the housing seatings 17 of the other pair of containing elements 16.

The zone where this condition occurs is indicated as the alignment zone 18 and corresponds approximately to the reciprocal tangent zone of the circular rotation paths made by the housing seatings 17.

In the alignment zone 18, the peripheral speed of rotation of the housing seatings 17 of the first capstan 12 is the same and concordant with the peripheral speed of rotation of the housing seatings 17 of the second capstan 13.

In fact, the first capstan 12 is made to rotate with an angular speed of equal intensity, but in an opposite direction with respect to the angular speed of the second capstan 13.

By aligned we mean that the pair of housing seatings 17 of the first capstan 12 has a housing axis H common to the pair of housing seatings 17 of the second capstan 13.

In accordance with possible solutions, it is possible to provide that the containing flanges 16a are provided on their circumferential periphery with a plurality of the pairs of housing seatings 17.

By way of example only, it can be provided that each containing flange 16a is provided with two, three, or four (see fig. 1) housing seatings 17 angularly distanced from each other.

Each pair of housing seatings 17 of the first capstan 12 is aligned, in an angular position of the capstans 12, 13, with a respective pair of housing seatings 17 of the second capstan 12.

According to possible variant embodiments, each of the first capstan 12 and the second capstan 13 can be provided with a plurality of pairs of containing elements 16 located angularly distanced from each other and each provided with respective housing seatings 17.

According to a possible embodiment, the containing elements 16 of the first capstan 12 are positioned inside the space defined between the containing elements 16 of the second capstan 13, or vice versa.

In particular, it can be provided that the containing elements 16 of the second capstan 13 define an interspace in which, during use, the containing elements 16 of the first capstan 12 are positioned with their portions.

In this condition the housing seatings 17 of the first capstan 12 are positioned inside the housing seatings 17 of the second capstan 13, and overlapping and aligned with the latter.

Specifically, it is provided that the distance between the containing elements 16 of the second capstan 13 is greater than or equal to the distance between the containing elements 16 of the first capstan 12.

According to the present invention, the drawing apparatus 10 comprises a gripping device 19 configured to hold the wire 1 1 and can be positioned in the housing seatings 17.

Once the operator has attached the wire 11 to the gripping device 19 and positioned the latter in a pair of housing seatings 17 of the first capstan 12, the drawing apparatus 10 allows to convey the wire 1 1 along the S-shaped path P. This solution allows the wire 1 1 to pass from the first capstan 12 to the second capstan 13 without the intervention of the operator being necessary, since in the alignment zone 18 the gripping device 19 automatically passes into the pair of housing seatings 17 of the second capstan 13.

Once the S-shaped path P has been completed, the operator can release the wire 1 1 from the gripping device 19 and supply it to the work station located downstream.

According to possible solutions, the gripping device 19 can comprise a support body 20 provided with a vice 26 suitable to grip and hold the wire 1 1.

The support body 20 is provided with support pins 22 which can be positioned in the housing seatings 17, that is, in a pair of the housing seatings 17. In particular, the support pins 22 can be installed protruding from one side and from the other side of the support body 20. The support pins 22 can be coaxial with each other.

Each support pin 22 comprises a containing disk 40 located on the free end of the support pin 22 itself.

The containing disk 40 delimits with the support body 20, or with a wall thereof, the portion of the support pin 22 housed in one of the housing seatings 17.

According to possible embodiments, for each support pin 22 the distance between the support body 20 and the containing disk 40 is equal to or greater than the sum of the thicknesses of two containing elements 16 of two separate capstans 12 and 13.

This aspect allows the gripping device 19 to pass from the first capstan 12 to the second capstan 13 without any hitches, since the positioning of the containing elements 16 of the second capstan 13 does not interfere with the position assumed by the gripping device 19 located in the housing seatings 17 of the first capstan 12.

The support body 20 can be in a single body, or it can be defined by at least a first part 23 and a second part 24 connected to each other with removable connection means 25.

In accordance with possible solutions, the gripping device 19 can be provided with a through cavity 21 through which the wire 1 1 is positioned. The through cavity 21 defines an axis of insertion X for the wire 1 1. The through cavity 21 can be disposed transversely, for example orthogonally, to the longitudinal axis of the support pins 22. In the drawings, the orthogonal axis is indicated by the reference Z.

According to some solutions, the vice 26 is installed in the through cavity 21. If it is necessary to perform specific operations on the components of the gripping device 19 disposed in the through cavity 21, it is possible to separate the parts 23 and 24 and to intervene easily on the components.

According to possible solutions, the through cavity 21 is provided with sliding guides 27 inclined with respect to the axis of insertion X and the vice 26 is provided with at least two jaws 28 mobile along the sliding guides 27 and defining a passage gap 29 to position the wire 11.

The passage gap 29 has a variable size in relation to the position assumed by the jaws 28 along the sliding guides 27.

Each sliding guide 27 is inclined with respect to the axis of insertion X by an acute angle of inclination Θ.

The angle of inclination Θ can be smaller than 45°.

The through cavity 21 has a first aperture 30 through which the wire 11 is inserted into the through cavity 21, and a second aperture 31 through which part of the wire 1 1 can protrude, for example with its leading end.

The sliding guides 27 diverge toward the second aperture 31.

The jaws 28 can be provided on at least part of their gripping surface 32 with surface irregularities 33 suitable to increase the action of gripping and holding the wire 1 1.

The gripping surface 32 can have a concave cross section shape to allow the wire 11 to be housed inside it as shown in fig. 4.

Each jaw 28 can be provided with a guide portion 34 which can be coupled with one of the sliding guides 27.

For example, each guide portion 34 (fig. 4) is T-shaped and is inserted in the sliding guides 27 having a mating shape.

By inserting the wire 1 1 into the passage gap 29 of the jaws 28 along the axis of insertion X in the direction of the second aperture 31, the jaws 28 slide along the sliding guides 27 until they are positioned with respect to the wire 1 1 so as to hold it. If a drawing action is exerted on the wire 1 1 exiting from the first aperture 30, the jaws 28 run along the sliding guides 27 in the direction of the first aperture 30, increasing the action of gripping and holding the wire 1 1.

According to possible embodiments, each jaw 28 is associated with an elastic holding device 35 configured to thrust the jaws 28 toward the first aperture 30 and ensure, during use, the certain contact with the wire 1 1.

According to possible embodiments, each jaw 28 can comprise at least one contact portion 36 able to cooperate with at least one abutment portion 37 located in the through cavity 21 to define at least the maximum opening position of the passage gap 29.

According to possible embodiments, each jaw 28 is provided with at least one hole 38 made in its thickness, for example open toward the contact portion 36 and in which a pin 39 attached to the support body 20 is inserted, for example in correspondence with the abutment portion 37.

A helical spring is installed on the pin 39 between the contact portion 36 and the abutment portion 37, and performs the function of the elastic holding device 35.

According to possible solutions, the drawing apparatus 10 comprises a switching device 41 located in the alignment zone 18.

The switching device 41 can be located between the drawing ring 14 and the housing seatings 17 of the first capstan 12.

The switching device 41 can be provided with at least a separating portion 41a able to condition the path of the gripping device 19 toward the housing seatings 17 of the second capstan 13. The separating portion 41a can be cuneiform.

According to possible embodiments, the switching device 41 can be provided with an actuator, such as a motor, able to position the separating portion 41a between the housing seatings 17 and the drawing ring 14 of the first capstan 12.

By way of example, the switching device 41 can comprise a tile, or other similar element.

The switching device 41 is configured to move the gripping device 19 from the housing seatings 17 of the first capstan 12 to the housing seatings 17 of the second capstan 13.

In other words, the switching device 41 is configured to mechanically condition the wire 1 1 held in the gripping device 19 to pass from a passage groove 15 of the first capstan 12 to the passage groove 15 of the second capstan 13 to allow the wire to proceed along the S-shaped path P.

In accordance with possible embodiments, the drawing apparatus 10 comprises a plurality of pressing devices 42 disposed on part of the periphery of the drawing rings 14 of the capstans 12 and 13 configured to keep the wire 1 1 pressed against the respective drawing rings 14.

This allows to condition the wire 11 to travel along the S-shaped path P while the latter completes the path P itself.

Each of the pressing devices 42 can comprise one or more sliding rollers 43 mobile between at least a first position in which the rollers 43 are in contact with the wire 11 and a second position in which the rollers 43 are not in contact with the wire 1 1.

According to possible embodiments, the pressing devices 42 can be provided with one or more articulated arms 44 able to position the rollers 43 on each occasion between the first and second position.

Formulations of the present invention also concern a method for drawing wire 1 1 which provides to make the wire 1 1 pass through the first capstan 12 and at least one second capstan 13.

According to the present invention, the drawing method provides to:

- attach the wire 11 to a gripping device 19,

- position the gripping device 19 with the wire 11 attached in a pair of housing seatings 17 provided on the periphery of the pair of containing elements 16 of the first capstan 12, said housing seatings 17 being open radially, with respect to the axis of rotation Rl , toward the outside,

- rotate at least the first capstan 12 to wind the wire 1 1 on part of the respective drawing ring 14 until it reaches the angular position in which the housing seatings 17 of the first capstan 12 are aligned with a pair of housing seatings 17 provided on the periphery of the pair of containing elements 16 of the second capstan 13, said housing seatings being open radially, with respect to the axis of rotation R2, toward the outside,

- transfer the gripping device 19 to the pair of housing seatings 17 of the second capstan 13, - rotate the second capstan 13 to wind the wire 11 on part of the respective drawing ring 14 of the second capstan 13.

The method can provide to remove the wire 1 1 from the gripping device 19 to supply it at exit from the drawing apparatus 10 to a work station located downstream thereof.

According to possible embodiments, the method provides to position a switching device 41 in the alignment zone 18 between the housing seatings 17 of the capstans 12 and 13 to move the gripping device 19 from the housing seatings 17 of the first capstan 12 to the housing seatings 17 of the second capstan 13. According to possible solutions, the method provides to position one or more pressing devices 42 in contact with the wire 1 1 against respective drawing rings 14.

It is clear that modifications and/or additions of parts can be made to the apparatus 10 and/or method for drawing wire 11 as described heretofore, without departing from the field and scope of the present invention.

According to possible embodiments, the drawing apparatus can comprise a feed device 45 located upstream of the first capstan 12 and/or downstream of the second capstan 13 and able to feed the wire 1 1 in a direction of feed. For example, the feed device can comprise a pair of mobile rollers between which the wire 11 passes.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of apparatus 10 and corresponding method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.