ITBO930135A1 - METHOD AND DEVICE FOR THE REALIZATION OF SEMI-FINISHED WORKS IN METALLIC WIRE. - Google Patents

Description

DESCRIPTION

patent for industrial invention

The present invention? relating to a device for making semi-finished metal wire products.

In particular, the present invention? relating to a device for the production of semi-finished metal wire products intended for the production of safety cages for caps of bottles of effervescent drinks.

Do the safety cages include, how? known, a main body adapted to wrap, in use, a cap of a bottle, and an annular belt suitable, in use, to allow the connection of the aforementioned main body to the neck of the bottle itself. The aforementioned main body and the belt are normally formed in a fully automatic production line consisting of a plurality of products. of work stations responsible for carrying out the various forming operations. The production rate of the line? obviously limited by the production rate of the single phases, among which the forming of a semi-finished product for the construction of the cage body is generally the most? criticism.

Purpose of the present invention? that of realizing a device for forming semi-finished products intended for the production of safety cages, and in particular of the bodies of the cage, which allows to obtain high production rates, and at the same time is simple and economical to produce.

According to the present invention, a device is provided for making semi-finished metal wire products, characterized in that it comprises bending means suitable for bending a metal wire to form a closed loop of a substantially circular shape; a station for forming the said semi-finished product, in which the said ring? adapted to be arranged in a substantially coaxial position with a first axis; a plurality? of forming units arranged in said forming station and each provided with a relative gripping head, the gripping heads being arranged along respective second axes substantially radial with respect to said first axis, and being able to positively couple to said ring in order to bind the ring itself in a plurality? of points delimiting respective sections of the ring; thrust means which can be associated with each of said portions to advance an intermediate portion of each of said portions towards said first axis along a third axis substantially radial with respect to said first axis, and to bring respective end portions of said portions into positions adjacent to the respective terminal portions of the adjacent sections; and first actuating means for rotating the said gripping heads around the respective said second axes to twist the said end portions close together.

Preferably, in the device of the type described above, the said second axes all lie in a forming plane orthogonal to the said first axis, and extend in a radial pattern from the first axis itself in angular positions equally spaced.

The present invention also relates to a method for manufacturing semi-finished metal wire products.

According to the present invention, a method is provided for the production of semi-finished metal wire products, characterized in that it comprises the steps of bending a metal wire so as to form a closed loop of a substantially circular shape; to constrain, in correspondence with a forming station and through a plurality of of gripping heads, said ring in a substantially coaxial position with a first axis and in a plurality of of points delimiting respective portions of the ring itself, said gripping heads being movable along respective second axes substantially radial with respect to said first axis; to advance, by means of thrust means, an intermediate portion of each said section towards said first axis along a respective third axis substantially radial with respect to said first axis so as to bring respective end portions of each of said sections into positions substantially adjacent to the respective terminal portions of the adjacent sections; and to twist the said end portions substantially close together by rotating the said gripping heads around the respective said second axes.

Preferably, the method described above comprises the step of forcing the said intermediate portions against a forming surface substantially coaxial to the said first axis and able to be arranged inside the said ring, and of keeping the intermediate portions themselves locked against the said surface of forming during the twisting step of the said end portions.

Will the invention come? now described with reference to the attached drawings, which illustrate a non-limiting example of embodiment, in which:

figure 1? a bottom view, with parts removed for clarity, of a preferred embodiment of the device according to the present invention;

Figure 2? a perspective view of a safety cage for caps of bottles of sparkling drinks;

figure 3? a section, on an enlarged scale, along the line III-III of Figure 1; And

figure 4? a partial top view, with parts removed for clarity, of the device of Figure 1 illustrated in a different operating condition.

In the attached figures, with 1? indicated a device for making semi-finished products 2 (Figure 3) made from a metal wire 3, and intended for the production of safety cages 4 for bottle caps (not shown) of sparkling beverages.

In particular, the device 1 forms part of a line (not shown) for the automatic realization of the cages 4. The cages 4 (figure 2) each comprise an annular belt 6 adapted to be tightened on a neck of a relative bottle (not shown), and a main body 7 suitable for wrapping a closure cap of the aforementioned bottle (not shown). The body 7, of which the semi-finished product 2 constitutes the flat development, comprises a plurality of of uprights 8, which are coupled, each, at its own end, to the belt 6, and converge to form, in correspondence of one of their ends? opposite, an annular connecting element 9.

With reference to Figures 1 and 3, the device 1 comprises a frame 9a having a substantially vertical central channel 9b, and a cylindrical tubular rod 10, which extends inside the channel 9b coaxially to an axis 11 of the channel 9b itself, and has an external radial flange 12 connected to its own intermediate portion. The flange 12? provided with four radial slots 13 forming an angle of 90 ° to each other, and with a circular groove 14, which? obtained on a front surface of the flange 12 itself facing downwards in a coaxial position with the axis 11, and intersects the slots 13 themselves. The rod 10 has its own upper terminal portion connected to a linear actuator 15 of a known type adapted to move the rod 10 itself along the axis 11 to move the flange 12 between a loading station 16, in which the wire 3 is brought into engagement in a known manner with the groove 12 and is subsequently cut by means of a cutting unit, known and not illustrated, to form a closed circular ring 17 (Figure 1), and a forming station 18, in which the ring 17 formed it is extracted from the groove 12 for further processing.

As illustrated in Figure 1, the device 1 comprises four units? 19 are arranged in the station 18 around the rod 10 and are angularly equidistant from each other by 90 °. In particular, in station 18, the units? 19 are each arranged in correspondence with a relative slot 13 and are adapted to constrain the ring 17 in four equally spaced points and define relative portions 20 of the ring 17 itself to keep the ring 17 in a coaxial position with the axis 11 and coplanar to a forming plane F orthogonal to the axis 11 itself and to the plane of Figure 2.

Again with reference to Figure 1, the device 1 further comprises four thrust units 21, which are also arranged in the station 18 around the rod 10 in angularly equally spaced positions. Are the groups 21 interspersed with the units? 19 of forming, and are each able to advance a median portion 22 of a relative portion 20 towards an external surface 23 of the rod 10 so as to bring the end portions 24 of the relative portion 20 each in a position substantially adjacent to a relative end portion 24 of an adjacent section 20.

In particular, the groups 21 each comprise a fixed guide 25, and a slide 26, which? slidingly coupled to the guide 25 itself, and supports a thrust head 27. The heads 27 are each shaped in such a way as to be coupled to a respective median portion 22, and are movable, together with the relative slides 26, along a relative axis 28, which coincides with the axis of the relative group 21, intersects orthogonally axis 11 and lies in the P plane. Each of the slides 26? movable along the relative guide 25 under the thrust of a sprocket-toothed transmission 29 between an advanced operative position, in which the head 27 itself? adapted to clamp the relative median portion 22 against the aforementioned surface 23 of the rod 10, and a retracted rest position, in which the head 27 itself allows the flange 12 to access the forming station 18.

During the movement of the heads 27 from the rear position to the advanced position, the ring 17? retained by the units? 19, which, according to what is better illustrated in Figure 3, each comprise a gripper head 31 associated with the frame 9a, and adapted to constrain the ring 17 in a relative aforementioned point.

In particular, the frame 9a has, for each unit? 19 a seat 32, whose axis 33 intersects orthogonally the axis 11, lies in the plane P, and coincides with the axis of the relative unit? 19. Each of the seats 32 defines a guide for a relative tubular sleeve 34 axially sliding therein, and, in turn, rotatably engaged and in an axially fixed position by a hollow shaft 35 coaxial to the axis 33 and defining a support of the relative head 31.

The sleeves 34 are movable along their respective axes 33 under the thrust of a cam-tappet device 36 adapted to move each of the heads 31 between a rear end position, in which the heads 31 themselves partially engage the relative seats 32 so as to such as to allow the flange 12 to access the station 18, and an advanced end-of-stroke position, in which the heads 31 themselves are able to release the finished semi-finished product 2.

The device 36 comprises a cam 37 common to all the sleeves 34, and respective tappet elements 38.

coupled to the cam 37, on the one hand, and to the relative sleeves 34 on the other. Cam 37? defined by an annular groove, which? obtained in a central body of a toothed wheel 39 rotatable with respect to the frame 9a, and has its own axis of symmetry coinciding with the axis of the wheel 39 itself, and a variable radius. In particular, the wheel 39? coupled to the frame 9a in a rotatable manner around the axis 11 in a position below the seats 32, and has an external toothing meshing with an external toothing of a motorized drive wheel 40, which? rotatable about a relative axis 41 parallel to the axis 11 to rotate the wheel 39 itself with respect to the frame 9a in an anti-clockwise direction in Figure 3.

With reference to Figure 4, the aforementioned groove? defined by four identical contiguous groove portions 42 and having an angular width equal to 90 °. The groove? therefore periodic with a period of 90 ?. Each portion 42 comprises, proceeding in the opposite direction to the direction of rotation of the wheel 39, a first curvilinear portion 43 with a substantially constant radius, a second straight portion 44 with a decreasing radius, a third, re-curvilinear portion 45 having a substantially constant radius of value smaller than that of the first section 43, a fourth section 46 substantially rectilinear and with a slightly decreasing radius, and a fifth section 47 inclined substantially straight with an increasing radius.

Again with reference to Figure 3, the gripping heads 31 are coupled to the relative sleeves 34 by means of the relative shafts 35, each of which? rotatable about the respective axis 33 under the thrust of a gear wheel transmission 48. This transmission comprises a common driving wheel 50, and a plurality of of driven toothed wheels each coupled to the relative shaft 35 by means of a splined coupling 51, and maintained in an axially fixed position with respect to the relative frame 9a by a radial pin 52. An end portion of the pin 52? integrally fixed to the frame 9a, and an opposite end portion slidingly engages a circumferential groove formed in a sleeve 53 coaxial and integral with the wheel 49. The wheel 50? coupled to the frame 9a to rotate around the axis 11, and comprises an external front toothing meshing with the toothing of the wheels 49, and a peripheral toothing meshing with an external peripheral toothing of a control wheel 54 for a control device, known and not illustrated, adapted to activate the wheel 54 itself intermittently.

The gripping heads 31 each comprise a fork 55 integrally connected to an end portion of the relative shaft 35 facing the rod 10, and two rocker arm jaws 56, which are hinged to the arms 55a of the relative fork 55 itself through respective pins 57 orthogonal to the relative arms 55a and to the respective axis 33 to pivot around the axes of the pins 57 under the thrust of a relative actuator unit 58 between an open position and a closed position, in which they are able to embrace and constrain the 'ring 17.

In particular, the jaws 56 relating to a same head 31 are each provided with a peg 58a, which extends in correspondence with the peg 58a of the other jaw 56 to define, together with the other peg 58a itself and the relative jaws 56, and when the jaws 56 themselves are arranged in their closed position, an eye 59 able to be engaged with play by a respective portion of the ring 17. The jaws 56 relating to the same gripping head 31 have respective surfaces 61 between them facing and converging towards each other and towards the relative shaft 35.

The actuator assembly 58 comprises a control rod 66 coaxial with the relative shaft 35 and having one end of its own. a frusto-conical body 62 movable along the relative axis 33 and able to cooperate with the surfaces 61, and an annular reaction spring 63 engaging respective seats obtained on an external surface of the jaws 56 themselves in correspondence with the surfaces 61 to exert on the jaws 56 a antagonistic action to that exerted by the body 62.

The unit 58 also comprises a guide 64 integral with the frame 9a and extending in a direction parallel to the relative axis 33, and a slide 65 coupled to the guide 64 in a sliding manner. The control rod 66 engages the relative shaft 35 in an axially sliding manner, and has an end? opposite the body 62 protruding beyond the relative shaft 35 itself and coupled to the slide 65 through the interposition of a thrust bearing 67.

The slides 65, and therefore the relative rods 66, are movable along the relative guides 64 under the thrust of an actuation and control device 68, which comprises a cam 69 common to all the slides 65, and, for each of the slides 65 same, a tappet element 70, an end portion of which? integrally connected to the relative slide 65, and a terminal portion of which opposite? coupled to cam 69. In particular, cam 69? defined by an annular groove obtained on the body of the aforementioned wheel 39 in a concentric and external position to the groove defining the cam 37, and has a variable radius. Cam 69? defined by four equal and contiguous groove portions 71 and having an angular width equal to 90 °. The groove? therefore periodic with period of 90 ?, and each of the portions 71? obtained in correspondence with a relative portion 42. Each portion 71 comprises, proceeding in the opposite direction to the direction of rotation of the wheel 39, a first curvilinear portion 72 with a constant radius obtained parallel to the portion 43, a second straight portion 73 with a decreasing and slightly radius diverging with respect to the corresponding section 44, a third section 74 substantially rectilinear obtained in correspondence with the point of confluence of the sections 44 and 45 and with an increasing radius, a fourth curvilinear section 75 obtained in correspondence with the section 45 parallel to the section 45 itself and having a radius smaller than the radius of the first section 72, a fifth section 76 substantially rectilinear and substantially parallel to the section 46, a sixth section 77 straight with a decreasing radius, and a last section 78 inclined substantially straight with an increasing radius and slightly converging towards the corresponding section 47.

Again with reference to Figure 3, the device 1 finally comprises an extractor assembly 79, per se? known, arranged below the station 18 and along the axis 11 to pick up the finished semi-finished product 2 and to advance the semi-finished product 2 itself towards a further forming station, not shown.

The operation of the device 1 will come? now described starting from a cycle start condition, in which the thrust heads 27 are arranged in their retracted rest position, the flange 12? arranged in the loading station 16 and houses inside the groove 14 a piece of wire having its own edges arranged in correspondence with one of the gripping heads 31, the transmission 48 keeps the heads 31 themselves in a fixed angular position corresponding to a condition of orthogonality? between the pins 57 and the axis 11, and the wheel 39 carrying the cams 37 and 69? arranged in a determined angular position in which the elements 38 are arranged at the entrance of the relative portions 42 of the groove 37 and lock the gripping heads 31 in their retracted position, and the elements 70 are arranged at the entrance of the respective portions 71 of the groove 69 and keep the relative pairs of jaws 56 in their closed position.

Starting from this condition, the actuator 15 is activated, which moves the flange 12 in the station 18, and, at the same time, the wheel 39 which is rotated around the axis 11 by the wheel 40 counterclockwise in figure 3. During the displacement of the flange 12 towards the station 18, and following the rotation of the wheel 39, the tappet elements 38 and 70 travel along the respective portions 43 and 72 maintaining substantially unchanged both the axial position of the heads 31 with respect to the relative frames 30, and the angular position of the jaws 56 around the relative pins 52 with respect to the relative forks 55. When the flange 12 reaches the station 18, the jaws 56 are rotated, by means of the unit 58, around the respective pins 57 and brought into their position of opening under the control of the elements 70 which at the same instant enter and travel along the portions 73 and, at the same time, the gripping heads 31 are progressively moved in one direction. or intermediate operating position close to the aforementioned advanced end-of-stroke position by the action exerted on the slides 26 by the elements 38 which travel along the portions 44.

When the heads 31 reach the aforementioned intermediate operative position, the jaws 56 reach their open position, in which they receive a portion of the ring 17 together, and in which the respective pins 58a are arranged in such a position that their projection on plane P lies inside the ring 17.

At this point, the gripping heads 31 are kept in substantially fixed axial positions by the relative elements 38 which, during the rotation of the wheel 39, travel along the respective portions 45, and the jaws 56 are carried by the respective elements 70, which, at the same time , run along the respective sections 74, in their closed position, in which they constrain the ring 17 in a position coplanar with the plane P and coaxial with the axis 11.

Once the closing phase of the jaws 56 is completed, the actuator 15 is activated again, which returns the flange 12 to the loading station 16, while both the axial position of the heads 31 and the angular position of the jaws 56 with respect to the relative forks 55 remain unchanged in when the elements 38 continue to travel along the relative stretches 45 with constant curvature, and the elements 70 enter and travel along the stretches 75 also with constant curvature. During the persistence of this condition of invariance of the position of the heads 31 and of the jaws 56, the thrust units 21 are activated, each of which moves the respective thrust head 27 from its retracted position into its forward position and, consequently, the respective portion median 22 in contact with the surface 23, and the respective end portions 24 in positions adjacent to the end portions 24 relative to the adjacent heads 27.

As soon as the thrusting heads 27 have reached their advanced position, the gripping heads 31 are progressively advanced towards their advanced end-of-stroke position by the action of the relative elements 38 which travel along the portions 46, and, at the same time, are each rotated around the relative axis 33 by the transmission 48 which is activated by the aforementioned control device, not shown. During the rotation and movement of the gripping heads 31, the jaws 56 are kept in their closed position by the action of the relative elements 70 which run along the portions 76, and the terminal portions 24 of the aforementioned portions 20 are twisted together to form the uprights 8 of a relative body 7.

Once the torsion phase of the end portions 24 is completed, the gripping heads 31 are further advanced along their respective axes 33 towards their advanced end-of-stroke position by the action of the elements 38 which continue to travel along the portions 46, while the jaws 56 are brought back to their open position by the action of the elements 70 which, at the same time, run along the sections 77.

In this way, the semi-finished product 2 is released from the bond with the gripping heads 31, and, at this point, the gripping heads 31 are progressively moved back towards their rest position by the action of the elements 38 which, following the rotation of the wheel 39, run along the portions 47, and the jaws 56 are again brought back to their closed position by the action of the elements 70 which run along the portions 78. The semi-finished product 2 is engaged by the extractor assembly 79, which extracts it by uncoupling it from the rod 10 and moves it away from the station 18 as soon as the thrust heads 27 have been returned to their rear position by activating the transmission 29. The arrangement of all the members of the device 1? now corresponding to the cycle start condition described above, and the cycle can? be repeated again according to the same steps described.

From the foregoing, it is evident how the simplicity? realization associated with high reliability? functional allows to significantly raise the production rate of the device, which can? be associated with any wire-hood production line 4, significantly increasing the production rate of the line itself.

Finally, it is evident that modifications and variations can be made to the described device 1 without thereby departing from the scope of the present invention. For example, different devices can be provided for the rotation of the gripping heads 31 around the relative axes 33, as well as for the rotation of the gripping heads 31 around the relative axes 33. devices other than those described for the command and control of the thrust heads 27.

Claims (1)

R I V E N D I C A Z I O N I 1.- Device (1) for making semi-finished products (2) in metal wire, characterized by the fact that it comprises bending means (14) suitable for bending a metal wire (3) to form a closed ring (17) of substantially shape circular; a station (18) for forming the said semi-finished product (2), in which the said ring (17)? adapted to be arranged in a substantially coaxial position with a first axis (11); a plurality? of forming units (19) arranged in said forming station and each provided with a relative gripping head (31), the gripping heads (31) being arranged along respective second axes. (33) substantially radial with respect to said first axis (11), and being able to positively couple to said ring (17) to constrain the ring (17) itself in a plurality of of points delimiting respective portions (20) of the ring (17); thrust means (21) associable with each of said portions (20) to advance an intermediate portion (22) of each of the portions (20) themselves towards said first axis (11) along a third axis (28) substantially radial with respect to said first axis (11) / and for bringing respective end portions (24) of said portions (20) into positions adjacent to the respective end portions (24) of adjacent portions (20); and first actuator means (48) for rotating the said gripping heads (31) around the respective said second axes (22) to twist the said end portions (24) side by side together. 2.- Device according to claim 1, characterized in that said second axes (33) all lie in a forming plane (P) orthogonal to said first axis (11), and extend radially from the first axis (11) itself in angular positions equally spaced. 3.- Device according to Claim 2, characterized by the fact that the said third axes (28) all lie in the said forming plane (P) in positions interspersed with the said second axes (33), and equally spaced with respect to the said second axes (33). ) themselves. 4.- Device according to any one of the preceding claims, characterized in that it comprises a forming surface (23) coaxial to said first axis (11) and able to be arranged inside said ring (17); the said thrust means (21) comprising, for each said portion (20) of the ring (17), a thrusting head (27) movable along a relative said third axis (28) between a first rear end position, where the thrust head (27) itself? adapted to be arranged outside the relative said ring (17), and an advanced end-of-stroke position, in which the thrust head (21)? adapted to force the intermediate portion (22) of the relative said portion (20) of the ring (17) against the said forming surface (23). 5.- Device according to any one of the preceding claims, characterized by the fact that the said gripping heads (31) each comprise gripper means (56) suitable for positively coupling to the said ring (17), and by the fact that each of the said forming units (19) also comprises a guide (32) extending along the relative said second axis (33), and a slide (34) coupled to the guide (32) in an axially sliding manner and supporting a relative said head of socket (31); second actuator means (36) being coupled to said slides (34) to move each of said gripping heads (31) between an advanced operative position, in which the relative said gripper means (56) are able to positively engage the said ring (17) in a respective said point, and a rearward rest position, in which the pincer means (56) themselves are able to be arranged outside the said ring (17), the said first actuator means (48) being able to rotate the said gripping heads (31) only when the gripping heads (31) themselves are arranged in proximity to each other. of their advanced operational position. 6.- Device according to Claim 5, characterized in that said second actuator means (36) comprise a first movable cam (37), and, for each said gripping head (31), a first tappet element (38) coupled to the first cam (37), on the one hand, and to the relative said slide (34), on the other. 7.- Device according to Claim 6, characterized in that the said gripper means comprise a pair of jaws (56), and the said forming units (19) further comprise, each, third actuator means (61,62,63 ) associated with each of said gripping heads (31) to cooperate with the relative jaws (56), and control means (68) of said third actuator means (61,62,63) to move the jaws (56) of each gripping head (31) with respect to each other between an open position and a closed position, in which they constrain said ring (17) to each other. 8.- Device according to Claim 7, characterized in that said control means (68) comprise a second movable cam (69), and, for each gripping head (31), a second coupled tappet element (70) to said second cam and associated with said third actuator means (61,62,63). 9.- Device according to Claim 8, characterized in that said third actuator means (61,62,63) comprise an inclined plane device (61,62) interposed between the relative jaws (56), and elastic means (63 ) adapted to exert on the relative jaws (56) themselves an antagonistic action to that exerted by the relative said inclined plane device (61,62). 10.- Device according to any one of claims 6 to 9, characterized in that it comprises a motorized wheel (39) arranged in a coaxial position to said first axis (11) and rotatable around the first axis (11) itself with respect to said groups forming (19); said first and second cam being defined by a first (37) and, respectively, by a second annular groove (69) with variable radius obtained on a front surface of said wheel (39) in positions that are concentric and substantially coaxial to each other said first axis (11); said first (37) and said second groove (69) being defined by a number of first (42) and, respectively, of second contiguous groove portions (71) equal to the number of said units. (19), each of said first (42) and second groove portions (71) having an angular width equal to an angle comprised between said second axes (33). 11.- Device according to Claim 10, characterized in that said first groove portions (42) each comprise, in succession, a first curvilinear portion (43) with substantially constant radius, a second straight portion (44) with radius decreasing, a third curved section (45) having a substantially constant radius and of a smaller value than that of said first section (43), a fourth section (46) substantially straight and with a slightly decreasing radius, and a fifth section (47) inclined substantially straight with increasing radius. 12.- Device according to Claim 11, characterized in that said second groove portions (71) each comprise, in succession, a first curvilinear portion (72) with substantially constant radius, a second portion (73) substantially rectilinear. decreasing radius, a third portion (74) substantially straight with a decreasing radius, a fourth curvilinear portion (75) having a radius smaller than the radius of said first portion (72) of the relative said second portion (71), a fifth portion (76) substantially straight with a slightly decreasing radius, a sixth straight section (77) with a decreasing radius, and a last, substantially straight inclined section (78) with an increasing radius. 13.- Device according to Claim 12, characterized in that the said third section (74) of the said second portions (71)? substantially obtained at a point of confluence of the said second (44) and third tracts (45) of the respective said first portions (42) of the first cam (37). 14.- Device according to any one of Claims 5 to 13, characterized in that the said gripping heads (31) each comprise a support shaft (35) coupled to a relative said slide (34) in a rotatable manner to said second axis (33) and in an axially fixed position, and said first actuator means comprise a transmission (48) in turn comprising a first driving toothed wheel (50) common to all the gripping heads (31), and, for each of the gripping heads (31) themselves, a second toothed wheel (49) engaged with said first toothed wheel (50) and coupled to a relative said hub (35) by means of a relative splined coupling (51). 15.- Method for making semi-finished products (2) in metal wire, characterized in that it comprises the steps of bending a metal wire (3) so as to form a closed ring (17) of a substantially circular shape; to constrain, in correspondence with a forming station (18) and through a plurality of of gripping heads (31), the said ring (17) in a substantially coaxial position with a first axis (11) and in a plurality of points delimiting respective portions (20) of the ring (17) itself, the said gripping heads (31) being movable along respective second axes (33) substantially radial with respect to said first axis (11); to advance, through thrust means (21), an intermediate portion (22) of each said portion (20) towards said first axis (11) along a respective third axis (28) substantially radial with respect to said first axis (11) so as to bring respective end portions (24) of each of said portions (20) into positions substantially adjacent to the respective end portions (24) of the adjacent portions (39); and to twist the said end portions (24) substantially next to each other by rotating the said gripping heads (31) around the respective said second axes (33) 16 Method according to claim 15, characterized in that it comprises the step of forcing the said intermediate portions (22) against a forming surface (23) substantially coaxial to the said first axis (11) and adapted to be arranged inside the said ring (17), and to keep the intermediate portions (22) themselves locked against the said forming surface (23) during the twisting step of the said end portions (24). 17.- Device for making semi-finished metal wire products, substantially as described with reference to the attached drawings. 18.- Method for making semi-finished metal wire products, substantially as described with reference to the attached drawings,