EP3959032A1

EP3959032A1 - A bending assembly for caps

Info

Publication number: EP3959032A1
Application number: EP20725937.5A
Authority: EP
Inventors: Mario Scarrone; Andrea Bellucci; Andrea Francesco BUSINARO
Original assignee: Telerobot SpA
Current assignee: IMA Industria Macchine Automatiche SpA
Priority date: 2019-04-23
Filing date: 2020-04-22
Publication date: 2022-03-02
Also published as: WO2020217186A1; CN113710413B; CN113710413A; IT201900006222A1

Abstract

A bending assembly (1) for caps is provided, comprising a cap (2) having a closure casing (20) with a base and a cylindrical wall surmounted by a perimeter edge (2a) on the inner wall of which a warranty seal (21) can be housed and a bending device comprising a gripping member (3) designed to firmly attach the closure casing (20), and a deformation member (4) comprising a locking element (400) and a deformation ring (42) mounted so it can slide about the locking element (400), wherein the gripping member (3) and the locking element (400) are mutually mobile along a shared main axis (1a) between a rest position, wherein the locking element (400) is moved away from the gripping member (3), and a locking position, wherein the locking element (400) penetrates the closure casing (20) when the latter is attached by the gripping member (3); wherein the deformation ring (42) is mounted so it can slide along the main axis (1a) and is mobile in relation to the locking element (400) between a hold position, wherein the deformation ring (42) and the gripping member (3) are at a first predefined distance, and a bending position wherein the deformation ring (42) and the gripping member (3) are at a second predefined distance less than the first predefined distance, and wherein the deformation ring (42) is configured and shaped to abut against the external wall of the perimeter edge (2a) when the deformation ring (42) is in the bending position and the locking element (400) is in the locking position, so as to plastically deform the edge (2a) with a pressure exerted exclusively on the external part of the edge (2a).

Description

DESCRIPTION

A BENDING ASSEMBLY FOR CAPS

This invention relates to a bending assembly for caps of the type specified in the preamble of the first claim.

In particular, this invention relates to a bending assembly designed to enable the assembly of the closure casing of a cap with the warranty seal partially contained inside the cap casing, for caps mainly used in the food sector.

As is well known, caps for food products are characterised by two main components: the closure casing and the warranty seal of the product designed to certify the correct closure of the food container or to indicate that it has been opened.

An example of a warranty seal is given by the rings that the screw caps comprise on common bottles of liquid, such as soft drinks or water or other liquids, and that are inserted by interlocking them with the closure casing.

The processing of caps, as previously described, is usually carried out by means of largely automated machinery capable of processing a plurality of parts, in particular caps, in series.

In particular, these machines may comprise straight or rotating mechanisms comprising spindles, arranged in a row or radially in relation to a central shaft, designed to remove caps or parts of caps from a continuous line and designed to process the caps themselves, or at least part of their components, along the processing line.

Once the processing is complete, the completed caps are conveyed back on a line away from the processing machinery.

Generally, within the cap production cycle, there is at least one cutting step and one coupling step. During the cutting step, a gripping member takes a portion of the cap, usually the warranty seal, in order to cut the latter and prepare it for coupling with the containment casing.

Usually, cutting is carried out by means of a rotating blade centred in relation to the gripping member and, therefore, both the gripping member and the cutting member are equipped with rotating or static spindles that are synchronised and mutually centred to enable precision processing.

Similarly, the coupling step is carried out by means of a gripping member, equipped with a rotating spindle, which takes the portions of the cap overlapping each other, and a crushing member that is designed to process part of the closure casing by plastic deformation while the latter is subjected to rotation by means of the spindle. In order to complete the coupling, it is therefore necessary to wait until the crushing member has passed through the entire edge of the cap and, in particular, the circumference defined by the closure casing.

The described prior art comprises, therefore, some significant drawbacks.

In particular, the crushing member, e.g. a movable probe along a predetermined direction, needs to be perfectly coordinated with the processing line and for the time required to complete the spindle rotation.

Therefore, any inaccuracies can lead to a plurality of subsequent errors in the processing of caps with catastrophic effects on production.

Moreover, the processing times, in particular the coupling times, strictly depend on the path taken by the crushing member and, therefore, are not very fast with the consequence that the production of finished caps is slowed down, compared, for example, to machinery performing other processing steps.

In this context, the technical task underlying this invention is to devise a bending assembly for caps that is capable of substantially avoiding at least some of the above-mentioned drawbacks.

Within said technical task, the invention has the important purpose of obtaining a bending assembly that is easily and more permanently synchronised with the supply line of caps and cap components in order to couple the warranty seal and the closure casing.

Another important purpose of the invention is to produce a bending assembly that enables the speed of producing finished caps to be increased avoiding, however, losing efficiency and coupling safety.

The technical task and specified purposes are achieved with a bending assembly for caps as claimed in the appended claim 1.

Preferred embodiments are described in the dependent claims.

The characteristics and benefits of the invention will be clarified in the following detailed description of some preferred embodiments of the invention, with reference to the accompanying drawings, wherein:

Fig. 1 shows a side section view of a bending assembly for caps according to the invention with bending finished;

Fig. 2 illustrates a simplified diagram of a part of a cap processing plant including a bending assembly for caps and/or cap components according to the invention.

Fig. 3a is a schematic view of a cap before bending; and

Fig. 3b represents a schematic view of a cap after bending with the attachment seat formed.

Fig. 5 shows a side view in cross-section of a bending assembly for caps according to the invention wherein the deformation ring is in the bending position and the locking element is in the locking position; and

Fig. 6 shows a side view in cross-section of a bending assembly for caps according to the invention wherein the deformation ring is in the hold position and said locking element is in the rest position.

In this document, when measurements, values, shapes, and geometric references (such as perpendicularity and parallelism) are associated with words like “approximately” or other similar terms, such as“almost” or“basically”, they shall be understood as without errors of measurement or imprecisions due to errors of production and/or manufacturing and, above all, without a slight divergence from the value, measurement, shape, or geometric reference with which it is associated. For example, if associated with a value, such terms preferably indicate a divergence of no more than 10% of the value itself.

Furthermore, when terms such as“first”, “second”, “upper”, “lower”, “main”, and “secondary” are used, they do not necessarily identify an order, relationship priority or relative position, but they can simply be used to distinguish different components more clearly from one another.

Unless otherwise stated, the measurements and data reported in this text shall be considered as performed in International Standard Atmosphere ICAO (ISO 2533: 1975).

With reference to the figures, the bending assembly for caps according to the invention is indicated as a whole by the reference number 1.

The assembly 1 includes a bending device designed to make caps 2 and at least one cap 2.

In general, the device 1 is preferably part of a processing plant 10 for caps 2.

The plant 10 is preferably a plant designed to process various types of caps 2, for example screw caps 2 for glass bottles or the like, for example, for the closure of paper and/or plastic packages, such as those produced by the company Tetra-Pak^® for containing fruit juice or milk or the like.

Preferably, the caps 2 being processed generally consist of at least two portions: a closure casing 20, e.g. made of metal, and a warranty seal 21 , e.g. made of polymer material.

The closure casing 20 is the portion of the cap designed to close the bottle. It can be made of various materials, for example polymer material or metal, more specifically aluminium, and may or may not include internal threads. Generally, but not necessarily, the cap 2 may also include a knurling or porous portion to increase the effectiveness of the grip and enable the user to easily unscrew the cap.

The warranty seal 21 is, however, preferably an annular portion, e.g. made of polymer, which can be interlocked with the inside of the closure casing 20 at the edge of the casing.

In particular, the closure casing preferably defines a perimeter edge 2a.

The perimeter edge 2a is the portion of the closure casing 20 designed to house the warranty seal 21 and preferably corresponds to the part of the closure casing 20 near the opening.

Therefore, the warranty seal 21 is, preferably, basically housed along the perimeter edge 2a of the closure casing 20.

In addition, usually the perimeter edge 2a is a larger portion, in cross-section, than the rest of the closure casing 20, so as to create a sort of shoulder and, therefore, a circular seat.

In summary, the closure casing 20 defines a base and a cylindrical wall surmounted by a perimeter edge 2a on the internal wall of which a warranty seal 21 can be housed.

The plant 10 shall preferably comprise at least the bending device and at least part of an assembly line 7.

The assembly line 7 is preferably a conveyor machine that is capable of moving caps 2 or cap components 2, e.g. the closure casing 20 and the warranty seal 21 separately, along a predetermined trajectory.

In particular, the assembly line 7 can be composed of a plurality of elements designed to define an assembly path 7a.

The assembly path 7a can be defined by a conveyor roller, or by other gripping elements that are moved and designed to transport objects on it.

In the current state of the art, there are many examples of different assembly lines 7, defining different assembly paths 7a, on the market.

The assembly line 7 also defines an assembly plane 7b.

The assembly plane 7b includes the assembly path 7a and is, preferably, the plane along which the caps 2 or cap components 2 are placed.

If the assembly line 7 includes a conventional conveyor roller, for example, the assembly plane 7b is defined by the surface of the belts moved by the rollers, while the assembly path 7a is defined by the movement direction the belt imposes on the rollers.

In any case, along at least part of the assembly path 7a, the plant 10 preferably includes one or more devices 1 .

Therefore, the bending device 1 preferably defines a way station included within the plant 10 itself.

If the caps 2 are of the type described above, the plant 10 may comprise a device dedicated to cutting the warranty seal 21 and corresponding assembly line 7 and a device 1 dedicated to the coupling between the closure casing 20 and the warranty seal 21. The latter is, therefore, preferably operationally connected to two assembly lines 7 of which, in detail, one transports the warranty seals 21 from the cutting device, and one transports the closure casings 20.

As already mentioned, the assembly comprises a bending device.

The bending device preferably defines at least one main axis 1a.

The main axis 1 a preferably defines the processing direction of the device 1 . Therefore, when the device 1 is part of a plant 10, the main axis 1 a is preferably perpendicular to the assembly plane 7b.

The bending device preferably comprises at least one gripping member 3 and one deformation member 4.

Here we do not discuss and describe the motor means for driving the members 3, 4 because they are already known in the state of the art or they are easy to produce, being mainly piston engines or, more generally, designed to allow the movement of an object along a specific direction.

In addition, the motor means may be powered in various ways and the members 3, 4 may be operationally connected to motors that are independent of each other or to a single motor coordinating the movements of both members 3, 4.

The gripping member 3 is preferably designed to permanently attach at least part of the cap 2.

In particular, the gripping member 3 is preferably designed to firmly attach the closure casing 20. The warranty seal 21 could itself be prepared and already partially housed inside the closure casing 20 and, therefore, also be attached to the gripping member 3.

However, the warranty seal 21 is preferably attached to the deformation member 4. The gripping member 3 therefore includes a first portion 30 and a second portion

31

The first portion 30 and the second portion 31 can, preferably, be mutually moved along the main axis 1 a in such a way as to lock the closure casing 20. In particular, the relative movement between the portions 30, 31 enables the closure casing 20 to be permanently locked.

In particular, the first portion 30 defines a support plane 3a.

The support plane 3a is preferably perpendicular to the main axis 1 a. Therefore, for example, the support plane 3a can be coplanar in relation to the assembly plane 7b or parallel to the same assembly plane 7b.

The second portion 31 defines, instead, a processing plane 3b.

The processing plane 3b is preferably perpendicular to the main axis 1 a.

Therefore, for example, the processing plane 3b can also be coplanar in relation to the assembly plane 7b or parallel to the same assembly plane 7b.

Preferably, the second portion 31 entirely surrounds the first portion 30 in such a way that the planes 3a, 3b create, when spaced apart from each other, at least one processing seat 32.

The processing seat 32 is preferably basically a compartment in which the closure casing 20 is partially contained. In addition, the closure casing 20 preferably rests on the support plane 3a and the perimeter edge 2a at least partially embraces said closure casing 20, protruding towards the processing plane 3b.

In a preferred embodiment, the first portion 30 can therefore be a cylinder centred along the main axis 1 a and the second portion 31 can be a hollow cylinder concentric to the first portion 30.

In this way, the processing seat 32 is basically counter-shaped to at least part of the closure casing 20.

In addition, the first portion 30 is preferably fixed between the two portions 30, 31 , while the second portion 31 moves and advances along the main axis 1 a in such a way as to space the planes 3a, 3b apart The support plane 3a is, therefore, preferably coplanar to the assembly plane 7b when the device of the assembly 1 is arranged in a plant 10.

In particular, the second portion 31 preferably advances towards the deformation member 4.

The deformation member 4 is preferably designed to plastically deform the cap 2. In particular, the deformation member 4 is designed to deform the cap 2 at the perimeter edge 2a when moved in relation to the gripping member 3 in such a way as to create an attachment seat 22 on the cap 2.

Therefore, the attachment seat 22 is basically the compartment formed by the deformed perimeter edge 2a and inside of which the warranty seal 21 is locked. The deformation member 4 and the gripping member 3 advantageously plastically deform the perimeter edge 2a under pressure exclusively by means of a single mutual translation along the main axis 1 a.

The deformation member 4 defines a first plane 4a.

The first plane 4a is preferably perpendicular to the main axis 1 a.

Therefore, for example, the first plane 4a can also be parallel in relation to the assembly plane 7b.

In addition, the deformation member 4 comprises a locking element 400.

The locking element 400 is preferably configured to lock the closure casing 20, which is placed on the gripping member 3, on command.

In this respect, the gripping member 3 and the locking element 400 are mutually mobile along the main axis 1 a. Therefore, the gripping member 3 and the locking element 400 define at least one rest position, wherein the locking element 400 is moved away from the gripping member 3, and one locking position, wherein the locking element 400 penetrates the closure casing 20 when the latter is attached by the gripping member 3.

The locking element 400, more specifically, includes a hollow cylindrical body 40. The hollow cylindrical body 40 is the part of the deformation member defining the first plane 4a. The term“flat” refers to the fact that the hollow cylindrical body 40 defines at least one lower annular edge designed to enable the locking element 400 to carry out those operations for which it is intended. Therefore, the hollow cylindrical body 40 preferably has a lower annular edge lying on the first plane 4a in such a way that, when the locking element 400 is in the locking position, the first plane 4a is aligned with the support plane 3a.

The hollow cylindrical body 40 can, in addition, be used to attach, as already mentioned, the warranty seal 21. In this case, the hollow cylindrical body 40 is preferably designed to remove the warranty seal 21 by inserting itself inside of it and removing it, for example, from the assembly path 7a.

Therefore, the hollow cylindrical body 40 preferably has dimensions compatible with the warranty seal 21 .

The locking element 400 preferably also comprises a piston 41.

The piston 41 extends along the longitudinal axis 1 a. In particular, the piston 41 is arranged within at least part of the hollow cylindrical body 40 and, therefore, the hollow cylindrical body 40 is concentric and slides along the main axis 1 a in relation to the piston 41 and vice versa.

In addition, it is designed to push part of the cap 2 along the main axis 1 a. In particular, the piston 41 defines a second plane 4b.

The second plane 4b is preferably perpendicular to the main axis 1 a.

Therefore, the second plane 4b can also be parallel in relation to the assembly plane 7b. In addition, the second plane 4b is placed coplanar with the first plane 4a when the piston 41 and the hollow cylindrical body 40 are in the locking position.

On the other hand, the planes 4a, 4b are spaced apart from each other, and the second plane 4b protrudes towards the gripping member 3, when the piston 41 pushes the closure casing 20 away from the hollow cylindrical body 40 and the locking element 400 is in, or is about to reach, the rest position.

The deformation member 4 also comprises a deformation ring 42.

The deformation ring 42 is preferably mounted so it can slide about the locking element 400. In addition, the deformation ring 42 is mounted so it can slide along the main axis 1 a and is mobile in relation to the locking element 400, in particular along said main axis 1 a.

The deformation ring 42 therefore defines, in relation to the locking element 400, at least one hold position, wherein said deformation ring 42 and the gripping member 3 are at a first predefined distance, and a bending position wherein the deformation ring 42 and the gripping member 3 are at a second predefined distance less than the first predefined distance.

Advantageously, the deformation ring 42 is configured and shaped to abut against an external wall of the perimeter edge 2a of the closure casing 20 when the deformation ring 42 is in the bending position and said locking element 400 is in the locking position.

Thus, the perimeter edge 2a of the closure casing 20 is plastically deformed with pressure exerted exclusively on the external part of the perimeter edge 2a of the closure casing 20.

In particular, the deformation ring 42 is configured to cooperate with the locking element 400 in order to drag the locking element 400 from the rest position to the locking position when the deformation ring 42 moves along a predetermined stretch from the rest position to the bending position.

In particular, the locking position is reached before the deformation ring 42 reaches the bending position.

Even more specifically, the deformation ring 42 moves smoothly over the hollow cylindrical body 40.

The deformation ring 42 preferably cooperates with the hollow cylindrical body 40 so that, when bending is completed, it drags the hollow cylindrical body 40 from the locking position to the rest position when the deformation ring 42 moves from the bending position to the hold position.

The deformation ring 42 begins to drag the hollow cylindrical body 40, then, after the deformation ring 42 has travelled a first predetermined stretch without any dragging. The rest position and the hold position are reached by dragging, preferably at the same time.

In order to determine the drag, the deformation ring 42 comprises a tooth 42a. The tooth 42a is, therefore, preferably mounted so it can slide within a seat 40a. The seat 40a preferably defines the predetermined stretch with its own stroke.

In addition, the seat 40a preferably extends along the main axis 1 a and is formed on the hollow cylindrical body 40.

As far as the movement of the piston 41 is concerned, the latter cooperates with the hollow cylindrical body 40 so that when the hollow cylindrical body 40 moves, dragged by the deformation ring 42, as described above, from the locking position to the rest position, the piston 41 stays in the locking position within the closure casing 20 for a predefined time and until the hollow cylindrical body 40 has been removed from the closure casing 20.

Thus, the piston 41 can exert its repelling force on the cap 2 ensuring that the cap remains resting on the gripping member 3.

The movement of the various components can be carried out freely, or can be carried out in opposition, or in contrast, with opposing elements.

In particular, the deformation ring 42 preferably acts in contrast to first elastic means 43 when in said bending position.

This means that when the deformation ring 42 exerts the thrust on the perimeter edge 2a, the thrust also depends on the stiffness of the first elastic means 43 adopted in the deformation member 4.

Similarly, the assembly 1 , in particular the deformation member 4 of the bending device, also comprises second elastic means 44.

The second elastic means 44 preferably cooperate with the piston 41 to bring it from the locking position to the rest position, when the hollow cylindrical body 40 is already in the rest position.

Basically, the second elastic means 44 exert a springback force that tends to restore the initial configuration of the locking element 400 wherein, that is, the first plane 4a and the second plane 4b are coplanar.

The first and second elastic means 43, 44 may, therefore, comprise opposing means of various kinds. They preferably comprise a respective spring mounted around the piston 41 .

The gripping member 3 and the deformation member 4 are, therefore, basically preferably aligned along the main axis 1 a. In this respect, the assembly 1 may include coupling means 5.

The coupling means 5 are configured to mechanically connect at least part of the gripping member 3 and part of the deformation member 4.

In particular, they define a C-shape, otherwise called a swan neck.

Therefore, the coupling means 5 connect the members 3, 4 in such a way that they are always aligned with the main axis 1 a.

In particular, when the bending device is included in a plant 10 and, as already mentioned, the main axis 1 a is perpendicular to the assembly plane 7b and, therefore, the coupling means 5 preferably define the C-shape along a plane perpendicular to the assembly path 7a.

In addition, the coupling means 5 preferably comprise at least two positioning holes

50

The positioning holes 50 are suitably arranged at the ends of the C-shape.

They are preferably designed to respectively house at least part of the gripping member 3 and part of the deformation member 4. In this way, the members 3, 4 can remain locked facing each other.

In detail, the positioning holes 50 are preferably centred along the main axis 1 a. Therefore, the positioning holes 50 define the ends of a guide 51.

The guide 51 is basically a preferred trajectory defined by the positioning holes 50 within which the caps 2 being processed pass through by means of the members 3, 4. The guide 51 therefore basically defines the alignment part of the members 3, 4. The processing guide 51 is preferably, suitably also centred along the main axis 1 a. The closure casing 20 and the warranty seal 21 can, therefore, be coupled when arranged inside the guide 51 .

In addition to what has already been described, the bending device of the assembly 1 comprises an auxiliary member 6.

The auxiliary member 6 is preferably basically an additional processing element to the members 3, 4 and can process together or alternately to them.

The auxiliary member 6 also preferably defines a movement direction 6a.

The movement direction 6a is basically the direction along which the auxiliary member 6 can be moved in order to process the caps 2 or the cap components 2 that pass through the bending device.

The movement direction 6a is preferably incident to the main axis 1 a. More suitably, the movement direction 6a is perpendicular to the main axis 1 a.

If the bending device is part of a plant 10, the movement direction 6a is preferably parallel to or aligned with the assembly plane 7b. In addition, it is preferably incident to the assembly path 7a, suitably perpendicular.

The auxiliary member 6 is, therefore, designed to move along the movement direction 6a to interact with a cap 2 or a component of the cap 2, preferably the closure casing 20. In particular, the auxiliary member 6 preferably interacts with the closure casing 20 inside the guide 51 for a predetermined time interval.

For example, in this respect, the auxiliary member 6 may comprise a clamp designed to lock, using friction, the cap 2, or a component of it, in a predefined position on the gripping member 3. In particular, the gripping member 6 is designed to arrange the closure casing 20 on the support plane 3a of the first portion 30 in a centred position in relation to the main axis 1 a. In this case, the auxiliary member 6 is basically a device for positioning the caps 2 inside the guide 51 in order to enable correct processing by means of the members 3, 4.

The auxiliary member 6 may then be arranged at a free end of the device 1 or partially housed in the coupling means 5. The coupling means 5 preferably include a through cavity 52.

The through cavity 52 preferably extends along the movement direction 6a inside the coupling means 5 and is designed to house at least part of the auxiliary member 6.

Therefore, the through cavity 52 behaves like a slot from which the auxiliary member 6 can move forward or backward.

The invention also comprises a new method for bending caps. Of course, this method is implemented using the assembly 1 as described above.

Therefore, the method comprises at least one preparation step, one attachment step, and one activation step.

In the preparation step, the assembly 1 is prepared. Therefore, in detail, during the preparation step, a cap 2, having a closure casing 20 with a base and a cylindrical wall surmounted by a perimeter edge 2a on the internal wall of which a warranty seal 21 can be housed, and a bending device as described above are prepared.

In the attachment step, the closure casing 20 is then firmly attached to the gripping member 3.

In the activation step, the deformation ring 42 is preferably activated from the hold position to the bending position by abutting against the external wall of the perimeter edge 2a of the closure casing 20 so that the perimeter edge 2a of the closure casing 20 is plastically deformed with pressure exerted exclusively on the external wall of the perimeter edge 2a of the closure casing 20.

In addition, during the activation step, the locking element 400 is preferably brought into contact with the base of the closure casing 20 before the deformation ring abuts against the closure casing 20.

The bending assembly for caps 1 according to the invention entails important advantages.

In fact, the bending device of the assembly 1 enables the coupling between the closure casing 20 and the warranty seal 21 to be carried out by making a single translatory movement and without needing to use spindles that can be rotated about the main axis 1a.

The efficiency of the deformation is, moreover, additionally guaranteed by the conformation of the gripping member 3, which makes it possible to significantly increase the processing speed within a plant 10.

Therefore, an additional advantage of the assembly 1 , and of the bending device in particular, is that it can be more easily and permanently synchronised with the supply line for caps and cap components in order to couple the warranty seal 21 and the closure casing 20.

In conclusion, an additional advantage is that bending device of the assembly 1 is safe, firmly holding the cap 2 portions inside the guide 51.

Variations falling within the scope of the inventive concept defined in the claims may be made to the invention. In this context, all details can be replaced by equivalent elements, and the materials, shapes, and dimensions may be any materials, shapes, and dimensions.

Claims

CLAI M S

1. The bending assembly (1 ) for caps, comprising:

- a cap (2) having a closure casing (20) with a base and a cylindrical wall surmounted by a perimeter edge (2a) on the internal wall of which a warranty seal (21 ) can be housed, and

- a bending device comprising:

- a gripping member (3) designed to firmly attach said closure casing (20),

- a deformation member (4) comprising a locking element (400) and a deformation ring (42) mounted so it can slide about said locking element (400),

- said gripping member (3) and said locking element (400) being mutually mobile along a shared main axis (1 a) between a rest position, wherein said locking element (400) is moved away from said gripping member (3), and a locking position, wherein said locking element (400) penetrates said closure casing (20) when the latter is attached by said gripping member (3);

- said deformation ring (42) being mounted so it can slide along said main axis (1 a) and being mobile in relation to said locking element (400) between a hold position, wherein said deformation ring (42) and said gripping member (3) are at a first predefined distance, and a bending position wherein said deformation ring (42) and said gripping member (3) are at a second predefined distance less than said first predefined distance,

and said assembly (1 ) being characterised in that

- said deformation ring (42) is configured and shaped to abut against an external wall of said perimeter edge (2a) of said closure casing (20) when said deformation ring (42) is in said bending position and said locking element (400) is in said locking position, so as to plastically deform said edge (2a) of said closure casing (20) with a pressure exerted exclusively on said external part of said perimeter edge (2a) of said closure casing (20).

2. The assembly (1 ) according to claim 1 , wherein said gripping member (3) includes at least one first portion (30) and one second portion (31 ) that can be mutually moved along said main axis (1 a) in such a way as to lock said closure casing (20).

3. The assembly (1 ) according to the previous claim, wherein said first portion (30) defines a support plane (3a) perpendicular to said main axis (1 a) and said second portion (31 ) defines a processing plane (3b) perpendicular to said main axis (1 a) and entirely surrounds said first portion (30) in such a way that said planes (3a, 3b) create, when spaced apart, at least one processing seat (32) wherein said closure casing (20) rests on said support plane (3a) and said perimeter edge (2a) at least partially embraces said closure casing (20).

4. The assembly (1 ) according to the previous claim, wherein said first portion (30) is a cylinder centred along said main axis (1 a) and said second portion (31 ) is a hollow cylinder concentric to said first portion (30), said processing seat (32) being counter-shaped to at least part of said closure casing (20).

5. The assembly (1 ) according to at least one previous claim, wherein said deformation ring (42) cooperates with said locking element (400) so as to drag said locking element (400) from said rest position to said locking position when said deformation ring (42) moves along a predetermined stretch from said rest position to said bending position, said locking position being reached before the deformation ring (42) reaches said bending position.

6. The assembly (1 ) according to at least one previous claim, wherein said deformation ring (42) acts in contrast to first elastic means (43) when in said bending position.

7. The assembly (1 ) according to at least one previous claim, wherein said locking element (400) comprises a piston (41 ) that extends along said main axis (1 a) and a hollow cylindrical body (40) concentric and sliding along said main axis (1 a) in relation to said piston (41 ).

8. The assembly (1 ) according to the previous claim, wherein said deformation ring (42) comprises a tooth (42a) mounted so it can slide within a seat (40a) extending along said main axis (1 a) and formed on said hollow cylindrical body (40).

9. The assembly (1 ) according to claim 7 or 8, wherein said deformation ring (42) cooperates with said hollow cylindrical body (40) so as to drag, at the end of the bending, said hollow cylindrical body (40) from said locking position to said rest position, when said deformation ring (42) moves from said bending position to said hold position, the deformation ring (42) beginning to drag the hollow cylindrical body

(40) after said deformation ring (42) has travelled a first predetermined stretch without any dragging, said rest position and said hold position being reached at the same time.

10. The assembly (1 ) according to the previous claim, wherein said piston

(41 ) cooperates with said hollow cylindrical body (40) so that when said hollow cylindrical body (40) moves, dragged by said deformation ring (42), from said locking position to said rest position, said piston (41 ) remains in said locking position within said closure casing (20) for a predetermined time and until said hollow cylindrical body (40) has been removed from said closure casing (20).

11. The assembly (1 ) according to the previous claim, comprising second elastic means (44) cooperating with said piston (41 to bring it from said locking position to said rest position, when said hollow cylindrical body (40) is already in said rest position.

12. The assembly (1 ) according to the previous claim, wherein said first and second elastic means (43, 44) comprise a respective spring mounted around said piston (41 ).

13. The assembly (1 ) according to any of the claims from 7-12, wherein said piston (41 ) has an abutment head lying on a second plane (4b) and said hollow cylindrical body (40) has an lower annular edge lying on a first plane (4a), said first and second planes being placed coplanar at least when the piston (41 ) and the hollow cylindrical body (40) are in the locking position.

14. The assembly (1 ) according to at least one previous claim, comprising an auxiliary member (6) defining a movement direction (6a) incident to said main axis (1 a) and designed to interact with said cap (2) for a predetermined time interval, said auxiliary member (6) comprising at least one clamp designed to lock said cap (2) using friction in a predefined position on said gripping member (3).

15. A cap processing plant (10) comprising at least part of an assembly line (7) for said caps (2) defining an assembly path (7a) and an assembly plane (7b) including said assembly path (7a) and at least one device (1 ) according to at least one previous claim arranged on said assembly plane (7b) in such a way that said main axis (1 a) is perpendicular to said assembly plane (7b).

16. A method for bending caps comprising the steps of:

- preparing a cap (2) having a closure casing (20) with a base and a cylindrical wall surmounted by a perimeter edge (2a) on the internal wall of which a warranty seal (21 ) can be housed, and

- preparing a bending device according to any one of the previous claims; - firmly attaching said closure casing (20) with said gripping member (3),

- activating said deformation ring (42) from said hold position to said bending position by abutting against said external wall of said perimeter edge (2a) of said closure casing (20) so as to plastically deform said perimeter edge (2a) of said closure casing (20) with a pressure exerted exclusively on said external wall of said perimeter edge (2a) of said closure casing (20), said locking element (400) coming into contact with said base of said closure casing (20) before said deformation ring abuts against said closure casing (20).