WO2024105558A1

WO2024105558A1 - Rolling machine

Info

Publication number: WO2024105558A1
Application number: PCT/IB2023/061479
Authority: WO
Inventors: Claudio Grazioli; Gianpaolo SOLAZZI; Mattia FEZZARDI
Original assignee: Grazioli Cesare S.R.L.
Priority date: 2022-11-14
Filing date: 2023-11-14
Publication date: 2024-05-23

Abstract

The present invention refers to an automatic rolling machine (1) that comprises at least one working unit (2) and at least one opposing vise (3). The opposing vise (3) is suitable for housing and locking an axisymmetric piece (4) when performing the rolling machining. The working unit (2) faces the opposing vise (3) and comprises a rotary support (20) a gripper (22) and a carriage (23). The rotary support (20) is provided with at least one rolling tool (21) and gives such rolling tool (21) a rotary motion about a working axis (W). The gripper (22) is controllable to close onto the axisymmetric piece so as to lock it. Finally, the carriage (23) is radially movable with respect to the working axis (W) and gives the rolling tool (21) a radial translational motion with respect to the working axis (W).

Description

"ROLLING MACHINE"

DESCRIPTION

[0001] The present invention relates to a rolling machine . As is known, rolling is a machining process without stock removal , that may be performed both hot and cold forming . By means of roll ing tools , also known as "rollers" , the surface of the piece to be machined is subj ected to such a pressure to generate a plastic deformation that allows to obtain grooves , threads or simply to modi fy the shape of the piece .

[0002] In particular, the obj ect of the present invention is a rolling machine for plastic deformation machining, preferably cold forming, performed on axisymmetric pieces , that is to say axisymmetric pieces , for example tubes , shafts , rods and the like .

[0003] Until now rolling operations were mainly carried out by hand : the piece was mounted on a mandrel and the operator, by manually actuating a wheel , guided the rolling tool into contact with the piece .

[0004] It is evident how plastic deformation operations performed manually require an operator with a high level of competence and professionalism . Furthermore , the fact that lathe rolling may only be performed by specialist operators implies elevated costs that the firm has to sustain for the training of the operators and refresher courses .

[0005] This without taking into account the fact that a manual rolling operation is intrinsically less precise than automated machining .

[0006] Disadvantageously, the necessity to increase production volumes has rendered manual rolling unsuitable for industrial applications wherein it is required to machine an elevated number of axisymmetric pieces during the same interval of time , or indeed within lesser time intervals compared to the state of the art .

[0007] A further disadvantageous aspect is due to the fact that ever more demanding requests - in terms relating to dimensional tolerance - have rendered manual rolling unsuitable for industrial applications wherein it is necessary to have a level of precision and repeatability that manual machining is not capable of ensuring .

[0008] Examples of rolling machines according to the state of the art are described in the documents DE 102006006256 Al , EP 1618973 Al and US 6216512 Bl .

[0009] The obj ect of the present invention is to propose a rolling machine and a method for performing rolling machining that is capable of overcoming the drawbacks mentioned above .

[0010] In particular, the obj ect of the present invention is that of describing a completely automated rolling machine wherein the only task for the operator is that of loading the axisymmetric pieces to be machined onto the rolling machine and unloading the machined pieces . The activity of the operator is therefore reduced to the mere loading/unloading of pieces .

[0011] Said obj ect is achieved with a rolling machine according to claim 1 and with a method for performing rolling machining according to claim 13 . The dependent claims describe preferred embodiments of the invention .

[0012] The features and the advantages of the rolling machine according to the invention shall be made readily apparent from the following description of preferred embodiment examples thereof , provided purely by way of a non-limiting example , with reference to the accompanying figures , wherein :

- Figure 1 shows a perspective view o f a rolling machine ;

- Figure 2 shows a lateral view of a working unit ;

Figure 2a shows a sectional view along the section plane A-A indicated in Figure 2 ;

Figure 2b shows a sectional view along the section plane B-B indicated in Figure 2 ;

- Figure 2c shows a perspective view of the working unit of Figure 2 ;

- Figure 2d shows a sectional view along a plane that is orthogonal to the section plane A-A containing a work axis ;

Figure 2e shows a perspective view of Figure 2d;

- Figure 3 shows a perspective view o f an oppos ing vise ;

- Figure 3a shows a front view of the opposing vise of Figure 3 ;

Figure 3b shows a sectional view along the section plane C-C of Figure 3a ;

- Figure 4 shows a perspective view o f a loading chute ;

- Figure 4a shows a front view of the Figure 4 ;

Figure 4b shows a sectional view along the section plane D-D of Figure 4a ;

Figure 4c shows a sectional view along the section plane E-E of Figure 4a ;

- Figure 5 shows a front view of a movement unit ;

- Figure 5a shows a plan view from above of the movement unit of Figure 5 ;

Figure 6 shows a perspective view of a loading and unloading unit , and

- Figures 7-7 i are steps of the method for performing rolling machining .

[0013] In the following description, elements common to the various embodiments represented in the drawings are indicated with the same reference numerals .

[0014] In said drawings , the reference numeral 1 is used to indicate , according to the invention, a rolling machine in the entirety thereof . Such rolling machine 1 is automatic insofar as it is suitable for performing machining operations without the intervention of an operator . Therefore , the operator has only the task of loading the axisymmetric pieces to be machined onto the rolling machine and unloading the machined pieces .

[0015] In one general embodiment , the rolling machine 1 for the plastic deformation machining of axisymmetric pieces , preferably tubes , comprises at least one working unit 2 and at least one opposing vise 3 . The opposing vise 3 is suitable for housing and locking an axisymmetric piece 4 when performing the rolling machining . In other words , the opposing clamp 3 is configured as an interlocking constraint for the axisymmetric piece .

[0016] The working unit 2 faces the opposing vise 3 and comprises a rotary support 20 , a gripper 22 and a carriage 23 . The rotary support 20 is provided with at least one rolling tool 21 , preferably three rolling tools . Such rotary support 20 confers a rotary motion to the rolling tool 21 about a working axis W . The gripper 22 is controllable to close onto the axisymmetric piece so as to lock it ; such axisymmetric piece is thus constrainable to both the working unit 2 and the opposing vise 3 . In other words , the gripper 22 - other than the opposing vise 3 - is configured as an interlocking constraint for the axisymmetric piece .

[0017] Preferably, the gripper 22 is an elastic gripper .

[0018] The carriage 23 is radially movable with respect to the working axis W . Such carriage 23 is connected to the rolling tool 21 so as to give the rolling tool a radial translational motion with respect to the working axis W .

[0019] The rolling tool 21 is therefore provided with both a rotational motion about the working axis W and a radial translational movement with respect to said working axis W . Such rotary and radial translational motions are configured to allow creating a groove 40 on the axisymmetric piece 4 .

[0020] In one embodiment , the working unit 2 also comprises a linear actuator 231 , a trans fer flange 232 and a steerer tube 233 .

[0021] The linear actuator 231 , preferably an electromechanical cylinder, is operable along an actuator axis A parallel to the working axis W .

[0022] The trans fer flange 232 is connected to a rod 231 ' of the linear actuator 231 .

[0023] The steerer tube 233 is engageable by the trans fer flange 232 , so as to be translationally controlled by the linear actuator 231 by means of the trans fer flange 232 . The steerer tube extends between a di stal end 233 ' engaged with the trans fer flange 232 and an opposed proximal end 233" bearing a cone-shaped profile 234 .

[0024] It should be noted that the term "distal" is to be understood as being distant with respect to a rolling region wherein the axisymmetric pieces is plastically deformed; the term "proximal" is instead to be understood as being in proximity to the rolling region .

[0025] The carriage 23 is provided with a counter-shaped profile 235 with respect to the cone-shaped profile 234 of the sheerer tube 233 . In particular, considering that the working unit 2 faces the opposing vise 3 , the profile 234 diverges towards the opposing vise 3 .

[0026] The sheerer tube 233 is engaged with the carriage 23 so that the linear advancement of the sheerer tube 23 causes the cone-shaped profile 234 to slide on the respective counter-shaped prof ile 234 of the carriage 23 . The linear motion of the sheerer tube 233 is thus trans formed into a radial translational movement of the carriage 23 .

[0027] Preferably, the engagement between the linear actuator 231 , the trans fer flange 232 , the sheerer tube 233 and the carriage 23 allows to obtain the radial translational movement with respect to the working axis W of the rolling tool 21 .

[0028] According to one embodiment , the rolling machine 1 also comprises a motor 200 , preferably of the asynchronous type . Such motor 200 is connected to the rotary support 20 by means of a trans fer unit 201 , for example said trans fer unit 201 comprising a drive pulley 202 , a driven pulley 203 and a toothed belt 204 . The motor 200 controls the rotation of the rotary support 20 . In other words , the rotary motion about the working axis W of the rolling tool 21 may be obtained from the engagement between the motor 200 , the trans fer unit 201 and the rotary support 20 .

[0029] In one embodiment , the rolling machine 1 also comprises a hydraulic cylinder 220 and a clamping sheerer tube 222 .

[0030] The hydraulic cylinder 220 is provided with an axially translatable piston 221 . For the purposes of this discussion, the term "axial" and the relative derivatives thereof are to be understood as referring to a direction parallel to the working axis W .

[0031] The clamping sheerer tube 222 extends between a rear end 222 ' engaged with the piston 221 and a front end 222" frontally delimited by a flared profile 223 diverging towards the opposing vise 3 . The term " front" - and the relative derivatives thereof - is to be understood as proximal or facing the opposing vise 3 . Vice versa, the term "rear" - and the relative derivatives thereof - is to be understood as distal or distant from the opposing vise 3.

[0032] The clamping sheerer tube 222 is operable by the piston 221 so as to translate axially.

[0033] The gripper 22 is provided with a plurality of slits 224 and is engaged by the front end 222" of the clamping sheerer tube 222.

[0034] Preferably the plurality of slits 224 has a substantially axial development, i.e. parallel to the working axis W.

[0035] The clamping sheerer tube 222, by translating axially, causes the front end 222" to slide on the gripper 22 and the flared profile 223, sliding on the gripper 22, applies a radial compression bias to said gripper 22 such as to reduce the clear opening through the plurality of slits 224. The gripper 22, by closing radially, is suitable therefore to lock the axisymmetric piece 4 and prevent such axisymmetric piece 4 from sliding along the working axis W. In other words, the gripper 22 closes radially reducing the diameter thereof and interlocking the axisymmetric piece.

[0036] According to one embodiment, the opposing vise 3 comprises a pair of jaws 31' , 31" rotationally freely connected to a pin 32 defining a aw rotation axis R.

[0037] Furthermore, the opposing vise 3 also comprises a pair of linear actuators 33' , 33", for example hydraulic or pneumatic cylinders , where each linear actuator 33 ' ; 33" of said pair of linear actuators 33 ' , 33" is connected to a respective j aw 31 ' ; 31" of said pair of j aws 31 ' , 31" .

[0038] The return stroke of the pair of linear actuators 33 ’ , 33" causes the pair of aws 31 ' , 31" to open, which by rotating about the pin 32 are arranged to house the axisymmetric piece 4 to be rolled or to unload the machined axisymmetric piece 4 . Conversely, the forward stroke of the pair of linear actuators 33 ’ , 33" causes the pair of j aws 31 ' , 31" to close , which by rotating about the pin 32 close to lock the axisymmetric piece 4 and prevent such axisymmetric piece 4 from sliding along a vise axis G coinciding with the working axis W .

[0039] Advantageously, the aperture of the pair of j aws 31 ' , 31" that rotate about the pin 32 , allows to insert ( and withdraw) the axisymmetric piece from above .

[0040] According to one embodiment , the axial length L measurable between a first circumferential profile 5 delimiting the gripping portion of the gripper 22 on the axisymmetric piece 4 and a second circumferential profile 6 delimiting the gripping portion of the opposing vise 3 on the axisymmetric piece 4 , is such as to allow the rolling tool 21 to create the groove . Such axial length L is comprised between 10 and 200 mm, preferably of between 10 and 30 mm .

[0041] Experimentally, it was observed that the axial length L may not be less than 10 mm due to encumbrance problems ; in fact , i f the axial length L were to be less than 10 mm, the rolling machining could not be performed . [0042] Advantageously, the axial length is of between 10 and 200 mm insofar as a greater axial length would render the groove undefined geometrically, i . e . out of tolerance . In other words , the groove would distend and it is therefore necessary to have an opposing vise 3 in the vicinity of the working unit 2 in order to contain the dimensional tolerances . I f the opposing vise 3 were to be missing or distant for the working unit 2 , the material would yield and the groove would distend . It has been observed experimentally that an axial length of between 10 and 30 mm allows to obtain greater groove geometrical and dimensional precision .

[0043] For the purposes of this discussion, the expression "distended groove" refers to a groove that does not conform to the required dimensional tolerances .

[0044] In accordance with one embodiment , the rolling machine 1 comprises a movement unit 7 .

[0045] Such movement unit 7 comprises , in turn, at least one pair of motors 70 ' , 70" ; 71 ' , 71" , for example brushless motors , and at least one pair of worm screws 2.' , 72"; 73' , 73", for example recirculating ball worm screws .

[0046] Each motor 70' ; 70"; 71' ; 71" of said pair of motors 70' , 70"; 71' , 71" operates a respective screw of said pair of worm screws 72' , 72"; 73' , 73".

[0047] Preferably, a first screw 72' ; 73' of the pair of worm screws 72' , 72"; 73' , 73" is engaged with the working unit 2 and a second screw 72"; 73" of the pair of worm screws 72' , 72"; 73' , 73" is engaged with the opposing vise 3.

[0048] In particular, the rotation of the first screw 72' ; 73' adjusting the axial position of the working unit 2 and the rotation of the second screw 72"; 73" adjusting the axial position of the opposing vise 3. The rotation of the first screw 72; 73' is therefore completely independent of the rotation of the second screw 72"; 73" and therefore the motion of the working unit 2 is independent of the motion of the opposing vise 3.

[0049] According to one embodiment, the rolling machine 1 comprises two working units 2 and two opposing vises 3. The movement unit 7 has a main extension along a movement axis M and is substantially symmetrical with respect to a mid-sagittal plane S. In this case, the movement unit 7 comprises two pairs of motors 70' , 70", 71' , 71" positioned at opposite ends of the movement unit 7, and two pairs of worm screws 72' , 72", 73' , 73".

[0050] Each pair of motors 70' , 70"; 71' , 71" operates a respective pair of worm screws 72' , 72"; 73' , 73", so that each pair of worm screws 72' , 72"; 73' , 73" engages one working unit of said two working units 2 and one opposing vise of said two opposing vises 3, respectively. Furthermore, each pair of worm screws 72' , 72"; 73' , 73" moves the working unit and the opposing vise independently of each other.

[0051] Preferably, each working unit of said two working units 2 cooperates with a respective opposing vise of said two opposing vises 3, in such a way as to perform rolling machining; two different rolling machinings may therefore be performed on the same one axisymmetric piece 4.

[0052] According to one embodiment, the rolling machine 1 comprises a loading chute 8 and an unloading chute 9.

[0053] The loading chute 8 is configured to allow manually positioning the axisymmetric piece 4 to be rolled by an operator. Furthermore, such loading chute 8 comprising a pair of guide partitions 80' , 80" which allow orienting the axisymmetric piece parallel to the working axis W.

[0054] The unloading chute 9 is configured to allow an operator to manually pick up the machined axisymmetric piece 4. [0055] Preferably, the rolling machine further comprises a conveying system 90 , for example a pilgered system, and such conveying system 90 is suitable for moving the machined axisymmetric piece 4 and placing it on the unloading chute 9 .

[0056] According to one embodiment , the rolling machine 1 comprises a selector device 81 in turn comprising, in turn, a plurality of cam members 82 , a polygonal shaft 84 and a pneumatic cylinder 85 .

[0057] The plurality of cam members 82 is arranged downstream of the loading chute 8 and a preferably "V" or "U" shaped recess 83 is obtained in each cam member of said plurality of cam members 82 to house the axisymmetric piece 4 to be rolled .

[0058] The polygonal , preferably hexagonal , shaft 84 is engaged with the plurality of cam members 82 .

[0059] The pneumatic cylinder 85 is connected to the polygonal shaft 84 by means of a linkage 86 , for example a lever crank or crank-rod mechanism . Such pneumatic cylinder 85 causes the rotation of the polygonal shaft 84 , and thus of the plurality of cam members 82 , so that the axisymmetric piece 4 positioned on the loading chute 8 is housable in the recess 83 .

[0060] According to one embodiment , the rolling machine 1 comprises a pair of feelers 87 configured to come into contact with the axisymmetric piece 4 to be rolled, so as to measure the length of the axisymmetric piece 4 and define a point of origin for the rolling machining . Such point of origin is configured as a " zero machine" point for starting the rolling .

[0061] Preferably, the pair of feelers 87 is arranged downstream of the loading chute 8 .

[0062] In one embodiment , the rolling machine 1 also comprises a handling portal 10 oriented in space along a first axis X parallel to the working axis W, a second axis Y orthogonal to the first axis X, and a third axis Z oriented vertically . The first X and second Y axes define a hori zontal plane and the third axi s Z is orthogonal to the hori zontal plane .

[0063] For the purposes of this discussion, the terms "hori zontal" and "vertical" are to be understood as referring to the rolling machine 1 when functioning, i . e . under operating conditions .

[0064] Furthermore , the handling portal 10 comprises a loading unit 11 and an unloading unit 12 . Such loading 11 and unloading 12 units are each provided with at least one picking gripper 13 , preferably two picking grippers , suitable for grasping and moving the axisymmetric piece 4 .

[0065] Preferably, the loading unit 11 and the unloading unit 12 are independently movable of each other along the first X, second Y and third Z axes.

[0066] According to the present invention, a method is also proposed for performing a rolling machining comprising the following steps.

[0067] i) Providing a rolling machine 1.

[0068] ii) Providing at least a first axisymmetric piece, a second axisymmetric piece, and a third axisymmetric piece to be rolled.

[0069] iii) Manually positioning the first, second, and third axisymmetric pieces on a loading chute 8 (Figure 7) . The positioning of the first, second and third axisymmetric pieces on the loading chute 8 is performed by the operator.

[0070] iv) Picking up the first axisymmetric piece with a loading unit 11 (Figure 7a) .

[0071] v) Moving the first axisymmetric piece by means of the loading unit 11, positioning and locking said first axisymmetric piece on the opposing vise 3 and the working unit 2 (Figures 7d and 7 e) .

[0072] Preferably, the loading unit 11 deposits the first axisymmetric piece in the opposing vise 3; after the pair of jaws 31' , 31" closes in order to clamp the axisymmetric workpiece, the working unit 2 moves towards the axisymmetric piece and the gripper 22 locks it. [0073] vi ) Performing the rolling machining ( Figure 7 f ) .

[0074] vii ) During the rolling machining, repeating step iv) to pick up the second axisymmetric piece and waiting for the end of the machining of the first axisymmetric piece .

[0075] viii ) Once the rolling machining is completed, picking up the first machined axisymmetric piece with the unloading unit 12 ( Figure 7g) .

[0076] Preferably, the unloading unit 12 grasps the first axisymmetric piece even before the rolling machining has concluded, in such a way as to reduce the downtime during the working cycle .

[0077] In particular, the gripper 22 opens in order to allow the working unit 2 to move away; whereafter the pair of j aws 31 ' , 31" opens in such a way as to allow the picking up of the axisymmetric pieces by the unloading unit 12 .

[0078] ix ) Positioning the unloading unit 12 in a stand-by region 100 of the handling portal 10 so as not to interfere with the loading unit 11 and repeating step v) to move the second axisymmetric piece , position and lock said second axisymmetric piece on the opposing vise 3 and the working unit 2 .

[0079] x ) While performing the rolling machining on the second axisymmetric piece , simultaneously moving the loading 11 and unloading 12 units . The loading unit 11 repeats the method from step iv) in order to pick up the third axisymmetric piece . The unloading unit 12 on the other hand places the first machined axisymmetric piece on a conveying system 90 which conveys said first axisymmetric piece on an unloading chute 9 ( Figures 7h and 7 i ) .

[0080] The first and subsequent machined axisymmetric pieces are manually removed from the unloading chute 9 by the operator .

[0081] According to one embodiment of the method, after the step iv) of picking up the first axisymmetric piece , the method further includes feeling the ends of said first axisymmetric piece with a pair of feelers 87 , for example spring feelers , so as to determine the length of the first axisymmetric piece and establish a point of origin for the rolling machining ( Figure 7c ) .

[0082] Innovatively, the rolling machine and method for performing rolling machining ful fill the intended obj ect . [0083] Advantageously, the rolling machine , obj ect of the present invention, is completely automated and does not therefore require the presence of a speciali zed operator . [0084] According to one advantageous aspect , the radial translational movement of the rolling tool allows to machine axisymmetric pieces of varying diameter and also allows to obtain grooves of varying depths .

[0085] According to a still further advantageous aspect , the rotary motion of the rolling tool allows to obtain the groove by means of plastic deformation in a completely automated manner, i . e . without the intervention of the operator .

[0086] Advantageously, the rolling improves the surface finish as well as the fatigue strength and work hardening of the material .

[0087] According to one advantageous aspect , the loading chute allows to create a kind of storage for the axisymmetric pieces to be rolling machined; similarly, the unloading chute acts as a storage for the machined axisymmetric pieces . The operator may therefore load ( and unload) more axisymmetric pieces at a time .

[0088] Advantageously, the method for performing rolling machining reduces the work cycle downtime and allows to complete a rolling machining in about 10-20 seconds , preferably in 15 seconds .

[0089] A person skilled in the art may make several changes and adj ustments to the embodiments of the roller machine and to the method for performing rolling machining according to the present invention and replace elements with other functionally equivalent ones in order to meet incidental needs , without departing from the scope of the following claims . Each of the features described as belonging to a possible embodiment may be obtained independently of the other described embodiments .

Claims

1. An automatic rolling machine (1) for plastic deformation machining on axisymmetric pieces, preferably tubes, comprising at least a working unit (2) and at least an opposing vise (3) , wherein the opposing vise (3) is suitable for housing and locking an axisymmetric piece (4) when performing the rolling machining, and wherein the working unit (2) faces the opposing vise (3) and comprises : a rotary support (20) provided with at least one rolling tool (21) , preferably three rolling tools, said rotary support (20) giving the rolling tool (21) a rotary motion about a working axis (W) ; a gripper (22) controllable to close onto the axisymmetric piece so as to lock it, said axisymmetric piece thus being constrainable to both the working unit (2) and the opposing vise (3) ;

- a carriage (23) radially movable with respect to the working axis (W) , said carriage (23) being connected to the rolling tool (21) so as to give said rolling tool a radial translational motion with respect to the working axis (W) , wherein the rolling tool (21) is provided with both a rotational motion about the working axis (W) and a radial translational movement with respect to said working axis (W) , said rotary and radial translational motions being configured to allow creating a groove (40) on the axisymmetric piece (4) .

2. A rolling machine (1) according to the preceding claim, wherein the working unit (2) comprises: a linear actuator (231) , preferably an electromechanical cylinder, operable along an actuator axis (A) parallel to the working axis (W) ;

- a transfer flange (232) connected to a rod ( 231 ’ ) of the linear actuator (231) ;

- a steerer tube (233) engageable by the transfer flange (232) , so as to be translationally controlled by the linear actuator (231) by means of said transfer flange (232) , the steerer tube extending between a distal end ( 233 ’ ) engaged with the transfer flange (232) and an opposed proximal end (233") bearing a cone-shaped profile (234) , wherein the carriage (23) is provided with a countershaped profile (235) with respect to the cone-shaped profile (234) of the steerer tube (233) , the steerer tube (233) being engaged with the carriage (23) so that the linear advancement of the steerer tube (23) causes the cone-shaped profile (234) to slide on the respective counter-shaped profile (234) of the carriage (23) , the linear motion of the steerer tube (233) thus being transformed into a radial translational movement of the carriage (23) .

3. A rolling machine (1) according to any one of the preceding claims, also comprising a motor (200) , preferably of the asynchronous type, said motor (200) being connected to the rotary support (20) by means of a transfer unit (201) , for example said transfer unit (201) comprising a drive pulley (202) , a driven pulley (203) , and a toothed belt (204) , said motor (200) controlling the rotation of the rotary support (20) .

4. A rolling machine (1) according to any one of the preceding claims, also comprising

- a hydraulic cylinder (220) provided with an axially translatable piston (221) ;

- a clamping steerer tube (222) extending between a rear end (222' ) engaged with the piston (221) and a front end (222") frontally delimited by a flared profile (223) diverging towards the opposing vise (3) , said clamping steerer tube (222) being operable by the piston (221) so as to translate axially, wherein the gripper (22) is provided with a plurality of slits (224) and is engaged by the front end (222") of the clamping steerer tube (222) , wherein, by translating axially, the clamping steerer tube (222) causes the front end (222") to slide on the gripper (22) , and wherein, by sliding on the gripper (22) , the flared profile (223) applies a radial compression bias to said gripper (22) such as to reduce the clear opening through the plurality of slits (224) , the gripper (22) , by closing radially, is suitable for locking the axisymmetric piece (4) and preventing said axisymmetric piece (4) from sliding along the working axis (W) .

5. A rolling machine (1) according to any one of the preceding claims, wherein the opposing vise (3) comprises a pair of jaws (31' , 31") rotationally freely connected to a pin (32) defining a aw rotation axis (R) , the opposing vise (3) further comprising a pair of linear actuators (33' , 33") , for example hydraulic or pneumatic cylinders, where each linear actuator (33' ; 33") of said pair of linear actuators (33’ , 33") is connected to a respective jaw (31' ; 31") of said pair of jaws (31' , 31") , wherein the return stroke of the pair of linear actuators (33’ , 33") causes the pair of jaws (31' , 31") to open, which by rotating about the pin (32) are arranged to house the axisymmetric piece (4) to be rolled or to unload the machined axisymmetric piece (4) , and wherein the forward stroke of the pair of linear actuators (33’ , 33") causes the pair of jaws (31' , 31") to close, which by rotating about the pin (32) close to lock the axisymmetric piece (4) and prevent said axisymmetric piece (4) from sliding along a vise axis (G) coinciding with the working axis (W) .

6. A rolling machine (1) according to any one of the preceding claims, wherein the axial length (L) measurable between a first circumferential profile (5) delimiting the gripping portion of the gripper (22) on the axisymmetric piece (4) and a second circumferential profile (6) delimiting the gripping portion of the opposing vise (3) on said axisymmetric piece (4) is such as to allow the rolling tool (21) to create the groove, said axial length (L) being between 10 and 200 mm, preferably being between 10 and 30 mm.

7. A rolling machine (1) according to any one of the preceding claims, comprising a movement unit (7) , said movement unit comprising:

- at least one pair of motors (70' , 70"; 71' , 71") , for example brushless motors, and

- at least one pair of worm screws (72' , 72"; 73' , 73") , for example recirculating ball worm screws, where each motor (70' ; 70"; 71' ; 71") of said pair of motors (70' , 70"; 71' , 71") operates a respective screw of said pair of worm screws (72' , 72"; 73' , 73") , wherein a first screw (72' ; 73' ) of the pair of worm screws (72' ,

12."; 13' , 73") is engaged with the working unit (2) and a second screw (72"; 73") of the pair of worm screws {12’ , 72"; 13’ , 73") is engaged with the opposing vise (3) , the rotation of the first screw {12’ ; 13' ) adjusting the axial position of the working unit (2) and the rotation of the second screw (72"; 73") adjusting the axial position of the opposing vise (3) .

8. A rolling machine (1) according to the preceding claim, comprising two working units (2) and two opposing vises (3) , wherein the movement unit (7) has a main extension along a movement axis (M) and is substantially symmetrical with respect to a mid-sagittal plane (S) , said movement unit (7) comprising:

- two pairs of motors (70' , 70", 71' , 71") positioned at opposite ends of the movement unit (7) , and

- two pairs of worm screws {12’ , 72", 13’ , 73") , each pair of motors (70' , 70"; 71' , 71") operating a respective pair of worm screws {12’ , 72"; 13’ , 73") , so that each pair of worm screws {12’ , 72"; 13’ , 73") engages one working unit of said two working units (2) and one opposing vise of said two opposing vises (3) , respectively, each pair of worm screws {12’ , 72"; 13’ , 73") further moving the working unit and the opposing vise independently of each other.

9. A rolling machine (1) according to any one of the preceding claims, comprising a loading chute (8) and an unloading chute (9) , the loading chute (8) being configured to allow manually positioning the axisymmetric piece (4) to be rolled by an operator, said loading chute (8) comprising a pair of guide partitions (80' , 80") which allow orienting the axisymmetric piece parallel to the working axis (W) , the unloading chute (9) being configured to allow an operator to manually pick up the machined axisymmetric piece (4) , the rolling machine further comprising a conveying system (90) , for example a pilgered system, said conveying system (90) being suitable for moving the machined axisymmetric piece (4) and place it on the unloading chute (9) .

10. A rolling machine (1) according to the preceding claim, comprising a selector device (81) in turn comprising :

- a plurality of cam members (82) arranged downstream of the loading chute (8) , a recess (83) , preferably a "V"- or "U"-shaped recess (83) , being obtained in each cam member of said plurality of cam members (82) to house the axisymmetric piece (4) to be rolled,

- a polygonal, preferably hexagonal, shaft (84) engaged with the plurality of cam members (82) ,

- a pneumatic cylinder (85) connected to the polygonal shaft (84) by means of a linkage (86) , said pneumatic cylinder (85) causing the rotation of the polygonal shaft (84) , and thus of the plurality of cam members (82) , so that the axisymmetric piece (4) positioned on the loading chute (8) is housable in the recess (83) .

11. A rolling machine (1) according to any one of the preceding claims, comprising a pair of feelers (87) configured to come into contact with the axisymmetric piece (4) to be rolled, so as to measure the length of the axisymmetric piece (4) and define a point of origin for the rolling machining.

12. A rolling machine (1) according to any one of the preceding claims, also comprising a handling portal (10) oriented in space along a first axis (X) parallel to the working axis (W) , a second axis (Y) orthogonal to the first axis (X) , and a third axis (Z) oriented vertically, said first (X) and second (Y) axes defining a horizontal plane, said third axis (Z) being orthogonal to the horizontal plane, the handling portal (10) comprising a loading unit (11) and an unloading unit (12) , said loading (11) and unloading (12) units each being provided with at least one picking gripper (13) , preferably two picking grippers, suitable for grasping and moving the axisymmetric piece (4) .

13. A method for performing a rolling machining comprising the following steps: i) providing a rolling machine (1) according to any one of the preceding claims; ii) providing at least a first axisymmetric piece, a second axisymmetric piece, and a third axisymmetric piece to be rolled; iii) manually positioning the first, second, and third axisymmetric pieces on a loading chute (8) ; iv) picking up the first axisymmetric piece with a loading unit (11) ; v) moving the first axisymmetric piece by means of the loading unit (11) , positioning and locking said first axisymmetric piece on the opposing vise (3) and the working unit (2) ; vi) performing the rolling machining; vii) during the rolling machining, repeating step iv) to pick up the second axisymmetric piece and waiting for the end of the machining of the first axisymmetric piece; viii) once the rolling machining is completed, picking up the first machined axisymmetric piece with an unloading unit ( 12 ) ; ix) positioning the unloading unit (12) in a stand-by region (100) of the handling portal (10) so as not to interfere with the loading unit (11) and repeating step v) to move the second axisymmetric piece, position and lock said second axisymmetric piece on the opposing vise (3) and the working unit (2) ; x) while performing the rolling machining on the second axisymmetric piece, simultaneously moving the loading

(11) and unloading (12) units, the loading unit (11) repeating the method from step iv) in order to pick up the third axisymmetric piece, the unloading unit (12) placing the first machined axisymmetric piece on a conveying system (90) which conveys said first axisymmetric piece on an unloading chute (9) .

14. A method for performing a rolling machining according to the preceding claim, wherein, after the step iv) of picking up the first axisymmetric piece, the method further includes feeling the ends of said first axisymmetric piece with a pair of feelers (87) , so as to determine the length of the first axisymmetric piece and establish a point of origin for the rolling machining.