WO2023067256A1

WO2023067256A1 - Method and assembly for stamping, comprising a rotary gripper

Info

Publication number: WO2023067256A1
Application number: PCT/FR2022/051716
Authority: WO
Inventors: Christophe Cools
Original assignee: Psa Automobiles Sa
Priority date: 2021-10-21
Filing date: 2022-09-12
Publication date: 2023-04-27
Also published as: FR3128390A1; FR3128390B1

Abstract

The invention relates to a stamping assembly (1) comprising a gripper (15) configured to enable the gripping of an end part (PT) of a workpiece (PC) that is to be cut and that is cut by a cutting blade (14) of the stamping assembly (1), the gripper (15) being able to effect a rotational and/or translational movement relative to a base plate (12) of the stamping assembly (1) and against which the workpiece (PC) that is to be cut is clamped. The mobility of the gripper (15) is brought about by the movement of an upper frame (11) of the stamping assembly (1) or of the press (13) relative to the base plate (12). The invention also relates to a stamping method employing such a gripper (15) of such a stamping assembly (1).

Description

Title of the invention: Stamping process and assembly comprising a rotating gripper

[1] The present invention claims the priority of French application 2111156 filed on October 21, 2021, the content of which (text, drawings and claims) is incorporated herein by reference.

[2] The technical context of the present invention is that of the machining of large sheet metal parts, particularly in the field of the automotive industry. More particularly, the invention relates to a stamping process and to a stamping assembly.

[3] Stamping sets are machine tools widely used in the automotive industry, in particular for cutting certain sheet metal parts, such as parts of the bodywork of motor vehicles.

[4] Such stamping assemblies generally comprise a fixed frame, a base supporting a part to be cut, the base being located at a distance from and facing the fixed frame, a press located between the base and the upper frame, the press being configured to generate a relative movement between, on the one hand, the upper frame and/or the base and, on the other hand, a cutting blade integral with the press, so as to be able to exert a shear force on the piece to be cut caught between the cutting blade and the base.

[5] A known drawback of these stamping assemblies results from their intensive use for cutting large series of sheet metal parts. Indeed, the offcuts formed by the parts of said sheet metal parts which have been cut by the stamping assembly must be extracted from the stamping assembly in order to be able to continue to operate correctly. This evacuation is not always possible or does not always take place in the right way, a large number of scraps thus being able to remain in place, under the stamping assembly. These successive stacks lead to jamming of the stamping assembly, then causing it to malfunction. It is then necessary to intervene manually to clear the scrap thus accumulated. These operations require interrupting the production line, reducing the production rates and the economic yields of such stamping sets.

[6] To circumvent this problem, we know the recutting of certain scrap formed by the stamping assembly in order to make it possible to evacuate them by simple effect of gravity in retention tanks placed below the stamping assembly . However, these recutting operations require increased tool complexity and/or functional complexity that is not necessarily desired.

[7] We also know the use of pushers which, placed at the level of the base of the stamping assembly, make it possible to facilitate the expulsion of the scrap formed by it, by pushing it in the direction of the retention tanks placed below the stamping assembly. Here again, the disadvantage of this solution lies in the material and/or functional complexity of the stamping assembly. In addition, it is not always possible to place such pushers on stamping sets.

[8] Moreover, it happens that the chute is deformed with the pusher rather than being pushed and evacuated by it in the direction of the retention tanks. In this case, the cutting scrap remains blocked in the lower part of the stamping assembly, at the level of the base. Here again, these blocked offcuts end up piling up to form an extra thickness of offcuts that can lead to poor positioning of the part to be cut, or even form a jam that can go so far as to break the cutting blade of the assembly of stamping.

[9] The object of the present invention is to provide a new stamping process and a new stamping assembly in order to at least largely solve the above problems and also to lead to other advantages.

[10] Another object of the invention is to facilitate the mass production of sheet metal parts by stamping.

[11] Another object of the invention is to propose limiting the stacking of offcuts in the stamping assembly and during its prolonged use. [12] Another object of the invention is to facilitate the evacuation of scrap during the implementation of the use of the stamping assembly.

[13] Another object of the invention is to increase machining rates, in particular by limiting break times, maintenance or non-use of the stamping assembly.

[14] According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a stamping process by a stamping assembly comprising a base supporting a part to be cut, a press configured to be able to generate a relative movement between the base and a cutting blade integral with the press, so as to exert a shearing force on the part to be cut caught between the cutting blade and the base, the stamping process comprising the following steps:

[15] - a step of depositing the part to be cut on the base of the stamping assembly, the press and the cutting blade being located at a distance from the base in order to allow the deposit of the part to be cut ;

[16] - a step of lowering the press in the direction of the base, so as to approach the cutting blade against the part to be cut;

[17] - a step of cutting the part to be cut by the cutting blade, resulting from the generation of a compressive force on said part to be cut caught between the cutting blade and the base.

[18] In accordance with the invention according to its first aspect, the stamping process also comprises the following steps:

[19] - a step of approaching a clamp making it possible to grasp an end part of the part to be cut located beyond the cutting blade relative to the base, the approaching step being concomitant with the lowering step;

[20] - a step of gripping the end part of the part to be cut by the pliers, the gripping step being concomitant with or prior to the cutting step; [21] - a step of evacuation of the terminal part resulting from the configuration of the gripper in a state of evacuation of the terminal part, the evacuation step being subsequent to the cutting step.

[22] The step of depositing the part to be cut on the base can be carried out by any means, and in particular by an automaton complementary to the stamping assembly. It aims to place the part to be cut on the base and facing the press and the cutting blade before the cutting step.

[23] The step of lowering the press in the direction of the base aims to produce a relative movement between the press and the base, so as to approach the cutting blade against the part to be cut. To this end, the stamping assembly advantageously comprises linear guide means in order to allow relative translation between the press and the base. During this lowering step, the piece to be cut is held against the base.

[24] The cutting step directly follows the lowering step. The cutting step consists of the application of the compressive force against the piece to be cut by the cutting blade, through the press which continues to produce the relative movement between said press and the base, such that mentioned previously.

[25] The gripper approach step consists of placing the gripper in direct proximity to the terminal part of the part to be cut. In other words, the gripper is oriented and/or moved in such a way that it is in a configuration in which it can grip the terminal part of the part to be cut.

[26] The step of gripping the terminal part of the part to be cut by the pliers consists of a step of configuring the jaws of the pliers in order to grip the terminal part by one edge.

[27] The step of evacuating the terminal part resulting from the configuration of the gripper in a state of evacuating the terminal part, the evacuation step being subsequent to the cutting step. The evacuation step includes a step of moving and/or rotating the gripper so as to extract the end part of the base and/or the press and to be able to place the end part of the part to be cut in a collection tray of the stamping assembly. [28] Of course, the stamping process according to the first aspect of the invention is not limited to its use in the automotive field. It is suitable for cutting metal parts or not presented in the form of plates or sheets, flat or not, and which can be cut by stamping.

[29] The stamping process in accordance with the first aspect of the invention thus makes it possible to facilitate the mass production of sheet metal parts by stamping, since the gripper makes it possible to extract each scrap produced by the stamping assembly during of its operation. Thus, the invention makes it possible to limit the piling up of offcuts in the stamping assembly and during its prolonged use.

[30] Consecutively, it is possible to increase machining rates, in particular by limiting downtime, maintenance or non-use of the stamping assembly, making it more efficient and more profitable.

[31] In a particularly clever way, the approach step is carried out by a purely mechanical coupling between the gripper and the press, the movement of the gripper being triggered and driven by the sole movement of the press relative to the base. In other words, the gripper and the press are linked together through a mechanical connection which induces the movement of the gripper when the press is in motion.

[32] The stamping process in accordance with the first aspect of the invention advantageously comprises at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination:

[33] - the approach step includes a step of rotation of the gripper from an angular configuration called parking to an angular configuration called gripping. The gripper is thus rotating around an axis of rotation.

[34] At least 90° between park configuration and grab configuration.

[35] - the approach step comprises a step of translation of the clamp relative to the base, the clamp being integral with the cutting blade. [36] - the approach step consists of a helical movement of the gripper relative to the base.

[37] - the gripping step includes a step of closing two jaws of the pliers, the jaws being articulated relative to each other and driven by a pneumatic control.

[38] - the evacuation step includes a step of rotation of the gripper from the gripping configuration to an angular configuration called evacuation.

[39] At least 90° between input configuration and evacuation configuration.

[40] According to a second aspect of the invention, there is proposed a stamping assembly comprising (i) an upper frame, (ii) a base supporting a part to be cut, the base being located at a distance from and facing the upper frame, (iii) a press located between the base and the upper frame, the press being configured to generate a relative displacement between, on the one hand, the upper frame and/or the base and, on the other hand, a cutting blade secured to the press, so as to be able to exert a shearing force on the part to be cut caught between the cutting blade and the base, (iv) a gripper making it possible to grasp an end part of the part to be cut located beyond the cutting blade relative to the base, the gripper being movable relative to the upper frame and/or the base, and (v) a control unit configured to implement the conformal stamping process to the first aspect of the invention or according to any one of its improvements.

[41] The clamp is preferably located opposite the base relative to the cutting blade. In a particularly advantageous manner, the stamping assembly comprises a helical connection between the gripper and the upper frame and/or the base. In general, the stamping assembly according to the first aspect of the invention comprises a mechanical connection connecting the clamp to the press, said mechanical connection authorizing and inducing the movement of the clamp when the press is driven by a relative movement with respect to the base. Preferably, the mechanical connection is of the type of transformation of a translational movement of the press into a rotational movement of the gripper, possibly supplemented by a translational movement similar to that of the press. [42] According to one embodiment, the stamping assembly comprises a pneumatic circuit configured to enable the opening and closing of the gripper to be controlled.

[43] Various embodiments of the invention are provided, integrating, according to all of their possible combinations, the various optional features set out here.

[44] Other characteristics and advantages of the invention will become apparent through the description which follows on the one hand, and several examples of embodiment given by way of indication and not limitation with reference to the appended schematic drawings on the other hand. , on which ones :

[45] [Fig.1] illustrates a schematic side view of the stamping assembly according to the first aspect of the invention and in a first state;

[46] [Fig.2] shows a schematic top view of the stamping assembly shown in FIGURE 1;

[47] [Fig.3] illustrates a schematic side view of the stamping assembly according to the first aspect of the invention and in a second state;

[48] [Fig.4] illustrates a schematic top view of the stamping assembly shown in FIGURE 3;

[49] [Fig.5] illustrates a schematic profile view of the stamping assembly according to the first aspect of the invention and in a third state;

[50] [Fig.6] illustrates a schematic top view of the stamping assembly shown in FIGURE 5;

[51] [Fig.7] illustrates a schematic profile view of the stamping assembly according to the first aspect of the invention and in a fifth state;

[52] [Fig.8] illustrates a schematic top view of the stamping assembly shown in FIGURE 7;

[53] [Fig.9] illustrates a schematic side view of the stamping assembly according to the first aspect of the invention and in a sixth state;

[54] [Fig .10] illustrates a schematic top view of the stamping assembly shown in FIGURE 9; [55] [Fig.11] illustrates a schematic profile view of the stamping assembly according to the first aspect of the invention and in a seventh state;

[56] [Fig .12] shows a schematic top view of the stamping assembly shown in FIGURE 11;

[57] [Fig.13] illustrates a schematic side view of the stamping assembly according to the first aspect of the invention and in an eighth state;

[58] [Fig.14] shows a schematic top view of the stamping assembly shown in FIGURE 13;

[59] [Fig.15] illustrates a synoptic view of the stamping process according to the second aspect of the invention.

[60] Of course, the features, variants and different embodiments of the invention may be associated with each other, in various combinations, insofar as they are not mutually exclusive or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from to the state of the prior art.

[61] In particular, all the variants and all the embodiments described can be combined with each other if nothing prevents this combination from a technical point of view.

[62] In the figures, the elements common to several figures retain the same reference.

[63] FIGURES 1 to 14 illustrate both a schematic embodiment of a stamping assembly 1 according to the second aspect of the invention, at various stages of a stamping process 2 according to the first aspect of the invention. The stamping process 2 is represented schematically and synthetically through FIGURE 15 and more explicitly through FIGURES 1 to 15.

[64] In accordance with the invention, the stamping assembly 1 comprises:

[65] - an upper frame 11; [66] - a base 12 supporting a piece to be cut PC, the base 12 being located at a distance and facing the upper frame 11;

[67] - a press 13 located between the base 12 and the upper frame 11, the press 13 being configured to generate a relative movement between, on the one hand, the upper frame 11 and / or the base 12 and, d on the other hand, a cutting blade 14 integral with the press 13, so as to be able to exert a shearing force on the part to be cut PC caught between the cutting blade 13 and the base 12;

[68] - a clamp 15 for gripping an end part PT of the piece to be cut PC located beyond the cutting blade 13 relative to the base 12, the clamp 15 being movable relative to the upper frame 11 and/or to the base 12;

[69] - a control unit configured to control the stamping assembly according to the stamping process 2 in accordance with the first aspect of the invention.

[70] The upper frame 11 is fixed or, preferably, movable in translation relative to the base 12. Indeed, in this case the translation of the upper frame simultaneously carries a movement of the press 13 and the cutting blade 14. This mobility in translation, called general, makes it possible to press the press 13 against the part to be cut PC, and more particularly to place said part to be cut PC in a vice between the press 13 and the base 12.

[71] The base 12 serves both to form a deposit surface for the part to be cut PC, but also to form a counterpart against which the press 13 exerts pressure to simultaneously hold the part to be cut PC in position, but also to be able to exert a shearing force on the end part PT of the piece to be cut located beyond a shearing edge 121 of the base 12.

[72] The shearing edge 121 is located directly above the cutting blade 14.

[73] The press 13 is movable in translation relative to the base 12 on the one hand, and optionally simultaneously movable in translation relative to the upper frame 11. Preferably, the press 13 is integrally connected to the upper frame 11 via a linear connection allowing a translation in the direction of the base 12 in order to be able to exert pressure against the piece to be cut PC; and the upper frame 11 is movable in translation relative to the base 12 in order to be able to "open" the stamping assembly 1 in order to allow the insertion of a new piece to be cut PC.

[74] The cutting blade 14 is configured to be able to shear the part to be cut PC, thanks to a cutting edge located opposite the base 12. In particular, the cutting blade 14 is located beyond the shearing edge 121 of the base, so that the cutting edge of the cutting blade 14 can cut by shearing the end part PT of the piece to be cut PC and thus allow its detachment.

[75] In a particularly advantageous manner, the stamping assembly 1 comprises a clamp 15 which makes it possible to grasp the end part PT of the part to be cut PC during a specific step of the stamping process which will be described later. The gripper 15 comprises a rotation axis 1 and, at a free end of the latter, two jaws 152 which make it possible to grasp by gripping the part ends the PT of the piece to be cut PC, once the shearing operations have been carried out.

[76] In order to allow perfectly synchronous operation of the clamp 15, the press 13 and the cutting blade 14, the clamp 15 is preferably secured to the cutting blade 14 by means of a mechanical connection 16 allowing at least one rotation and/or one translation. In particular, the mechanical connection 16 is configured to allow the clamp 15 to be established:

[77] - in a gripping state when the end part PT is being cut by the cutting blade 14 or directly after this operation;

[78] - in a state of evacuation of the terminal part PT when the press 13 and the cutting blade 14 move away again from the base 12 after the cutting operation; And

[79] - in a stationary state when the upper frame 11 and the press 13 are simultaneously raised in a distal position of the base 12, in order to allow the insertion of a new piece to be cut PC.

[80] In the case where the clamp 15 is rotatable around an axis 151, a first angle separating the stationary state from the gripping state of the clamp 15 is at least equal to 90° relative to the axis 151 of rotation of said gripper. Additionally, a second angle separating the state of evacuation from the state of gripping the clamp 15 is at least equal to 90° relative to the axis 151 of rotation of said clamp, the gripping state preferably being angularly distant 180° from the evacuation state.

[81] In a particularly advantageous manner, the mechanical connection 16 connecting the clamp 15 to the cutting blade 14 and/or to the upper frame 11 and/or to the base 12 is of the type of a helical connection. This configuration thus makes it possible to convert the translational movement operated between the press 13 and the base 12 and/or between the upper frame 11 and the base 12 into a rotational movement of the gripper 15 concomitantly with a translational movement parallel to that of the press 13 and/or the upper frame 11 and/or the base 12.

[82] According to a particularly clever implementation, the movement of the clamp 15 is induced by the movement of the press 13 and / or the cutting blade 14. Thus, the clamp 15 is not actuated by a motor member . On the contrary, its movement derives, via a possible mechanical transformation, from that of the press 13 and/or of the cutting blade 14 when one or the other is approached to the base 12 to carry out the cutting of the part. to cut PC.

[83] Additionally, the stamping assembly 1 comprises a pneumatic circuit making it possible to control the opening and closing of the jaws 152 of the gripper 15. In particular, the pneumatic circuit is configured to control an opening of the jaws 152 of the clamp 15 when the latter in its discharge state of the terminal part PT in order to allow release of the latter. The pneumatic circuit is configured to control an opening of the jaws 152 of the gripper 15 when the latter is in its stationary state. The pneumatic circuit is configured to control a closing of the jaws 152 of the pliers 15 when the latter in its gripping state of the terminal part PT in order to be able to grasp it during the cutting of the part to be cut PC.

[84] The stamping process 2 according to the first aspect of the invention will now be described with reference to FIGURES 1 to 15. By way of introductory remarks, the stamping process 2 comprises one or more steps making it possible to implement implements the stamping assembly 1 as described previously in any of its states mentioned in the preceding paragraphs.

[85] Stamping Process 2 involves the following steps:

[86] - a step 21 of depositing the part to be cut PC on the base 12 of the stamping assembly 1, the press 13 and the cutting blade 14 being located at a distance from the base 12 in order to allow depositing the part to be cut PC. The state of the stamping assembly 1 during the deposition step 21 is more precisely illustrated by FIGURES 1 and 2. In this state, the gripper 15 is in its stationary state;

[87] - a lowering step 22 of the press 13 in the direction of the base 12, so as to approach the cutting blade 14 against the part to be cut PC. In particular, the lowering step 22 comprises a first phase 221 in which the press 13 is lowered against the piece to be cut PC, so as to grip it between said press 13 and the base 12; and the lowering step includes a second phase 222 during which the upper frame 11 is lowered in the direction of the press 13 and the base 12 in order to approach the cutting blade 14 against the part to be cut PC. The state of the stamping assembly 1 during the first phase 221 of the lowering step 22 is illustrated in FIGURES 3 and 4. The state of the stamping assembly 1 during the second phase 222 of the lowering step 22 is illustrated in FIGURES 5 and 6;

[88] - a step 23 of approaching the gripper 15, the step of approaching 23 being concomitant with the step of lowering 22. Preferably, the step of approaching 23 takes the form of a helical transformation of the translational movement of the upper frame 11 in the direction of the base 12 into a rotational movement of the gripper 15 around its axis 151, accompanied by a translational movement of the said gripper 15 in order to bring it closer to the terminal part PT to be entered. As mentioned above, the approach step 23 takes the form of a movement induced by the lowering step 22. In other words, the approach step 23 is not a driving or controlled step. directly by a motor organ. The state of the stamping assembly 1 during the approach step 23 is illustrated in FIGURES 5 and 6; [89] - a step 24 of cutting the part to be cut PC by the cutting blade 14, resulting from the generation of a compression of said part to be cut PC caught between the cutting blade 14 and the base 12, causing a shearing force on the end part PT and leading to a detachment of the latter relative to the piece to be cut PC. The state of the stamping assembly 1 during the cutting step 24 is illustrated in FIGURES 7 and 8;

[90] - a step 25 of gripping the end part PT of the part to be cut PC by the gripper 15, the gripping step 25 being concomitant with or prior to the cutting step 24. During this gripping step 25, according to a first embodiment, the jaws 152 of the clamp 152 are controlled, preferably by a pneumatic circuit, in order to close on the terminal part PT and to grasp it and hold it in position during the step of cutting 24. According to a second preferred embodiment, during this gripping step 25, the jaws 152 of the clamp 15 are kept open around the end part PT. The state of the stamping assembly 1 during the gripping step 25 is illustrated in FIGURES 7 and 8, for the second embodiment;

[91] - an ascent step 26 of the upper frame 11, during which the cutting blade 14 is moved away from the part to be cut PC and from the end part PT which has just been cut and detached from said part to be cut PC. In the first embodiment mentioned above, the end part PT is already retained by the clamp 15 whose jaws are already closed. In the second embodiment mentioned above, the jaws 152 of the clamp 152 are controlled, preferably by a pneumatic circuit, in order to close on the terminal part PT and to grasp it and hold it in position during the ascent. of the cutting blade 14 during the ascent step 26. The state of the stamping assembly 1 during the ascent step 26 is illustrated in FIGURES 9 and 10;

[92] - an evacuation step 27 of the end part PT resulting from the configuration of the gripper 15 in its state of evacuation of the end part P, the evacuation step 27 being subsequent to the cutting step 25. To do this, the evacuation step 27 preferably includes a first step 271 of rotation of the gripper 15 around its axis 151 in order to orient the jaws 152, and the end part PT that they carry, in an orientation opposite to the shearing edge 121 of the base 12 relative to the axis 151. Subsequently, the evacuation step 27 includes a second step 272 for controlling the gripper 15 in order to open the jaws 152 and thus allow the release of the terminal part PT which they were carrying, in order to drop it by gravity towards the recovery bins of the stamping assembly 1. The state of the drawing assembly 1 during the first step 271 of the evacuation step 27 is illustrated in FIGURES 11 and 12. The state of the drawing assembly 1 during the second step 272 of the step of Vent 27 is shown in FIGURES 13 and 14.

[93] In summary, the invention relates to a stamping assembly 1 comprising a gripper 15 configured to allow gripping of an end portion PT of a part to be cut PC cut by a cutting blade 14 of the assembly. stamping 1, the clamp 15 being movable in rotation and / or in translation relative to a base 12 of the stamping assembly 1 and against which the piece to be cut PC is held in a vice. The mobility of the clamp 15 is induced by the movement of an upper frame 11 of the stamping assembly 1 or of the press 13, relative to the base 12. the invention also relates to a stamping process 2 putting implement such a gripper 15 of such a stamping assembly 1 .

[94] Of course, the invention is not limited to the examples that have just been described and many adjustments can be made to these examples without departing from the scope of the invention. In particular, the different characteristics, forms, variants and embodiments of the invention may be associated with each other in various combinations insofar as they are not incompatible or exclusive of each other. In particular, all the variants and embodiments described previously can be combined with one another.

Claims

[Claim 1] Stamping method (2) by a stamping assembly (1) comprising a base (12) supporting a part to be cut (PC), a press (13) configured to be able to generate a relative displacement between the base (12) and a cutting blade (14) integral with the press (13), so as to exert a shearing force on the part to be cut (PC) caught between the cutting blade (14) and the base ( 12), the stamping process (2) comprising the following steps:

- a step of depositing (21) the part to be cut (PC) on the base (12) of the stamping assembly (1), the press (13) and the cutting blade (14) being located at distance from the base (12) in order to allow the deposit of the piece to be cut (PC);

- a lowering step (22) of the press (13) in the direction of the base (12), so as to approach the cutting blade (14) against the piece to be cut (PC);

- a cutting step (24) of the part to be cut (PC) by the cutting blade (14), resulting from the generation of a compressive force on said part to be cut (PC) caught between the cutting blade ( 14) and the base (12); characterized in that the stamping process (2) further comprises the following steps:

- a step (23) for approaching a gripper (15) making it possible to grasp an end part (PT) of the part to be cut (PC) located beyond the cutting blade (14) relative to the base (12), the approach step (23) being concomitant with the lowering step (22);

- a gripping step (25) of the end part (PT) of the part to be cut (PC) by the gripper (15), the gripping step (25) being concomitant with or prior to the cutting step (24 );

- an evacuation step (27) of the terminal part (PT) resulting from the configuration of the gripper (15) in a state of evacuation of the terminal part (PT), the evacuation step (27) being subsequent to the cutting step (24).

[Claim 2] Stamping process (2) according to the preceding claim, in which the approaching step (23) comprises a step of rotation of the gripper (15) from a so-called parking angular configuration to a so-called gripping angular configuration.

[Claim 3] Stamping method (2) according to any one of the preceding claims, in which the step of approaching (23) comprises a step of translating the gripper (15) relative to the base (12) , the clamp (15) being secured to the cutting blade (14).

[Claim 4] Stamping process (2) according to claim 1, in which the approach step (23) consists of a helical movement of the gripper (13) relative to the base (12).

[Claim 5] Stamping method (2) according to any one of the preceding claims, in which the gripping step (25) comprises a step of closing two jaws (152) of the gripper (15), the jaws (152) being articulated relative to each other and driven by a pneumatic control.

[Claim 6] Stamping process (2) according to any one of the preceding claims, in which the evacuation step (27) comprises a step of rotating the gripper (15) from the gripping configuration to a configuration angle called evacuation.

[Claim 7] Stamping assembly (1) comprising:

- an upper frame (11);

- a base (12) supporting a piece to be cut (PC), the base (12) being located at a distance and facing the upper frame (11);

- a press (13) located between the base (12) and the upper frame (11), the press (13) being configured to generate a relative displacement between, on the one hand, the upper frame (11) and/or the base (12) and, on the other hand, a cutting blade (14) integral with the press (13), so as to be able to exert a shearing force on the piece to be cut (PC) caught between the cutting blade cutout (14) and the base (12);

- a gripper (15) for gripping an end part (PT) of the piece to be cut (PC) located beyond the cutting blade (14) relative to the base (12), the gripper (15) being movable relative to the upper frame (11) and / or the base (12); - a control unit configured to implement the stamping process (2) according to any one of the preceding claims.

[Claim 8] Stamping assembly (1) according to the preceding claim, wherein the stamping assembly (1) comprises a helical connection between the clamp (15) and the upper frame (11) and / or the base (12).

[Claim 9] Stamping assembly (1) according to any one of claims 7 or 8, wherein the stamping assembly (1) comprises a pneumatic circuit configured to allow control of the opening and closing of the pliers (15).