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Title:
METAL STRIP ACCUMULATOR AND STRIP ACCUMULATING METHOD THEREOF
Document Type and Number:
WIPO Patent Application WO/2023/089478
Kind Code:
A1
Abstract:
A metal strip accumulator for accumulating strip coming from a production line, said accumulator comprising a plurality of concentric annular structures with respect to a horizontal axis X, for accumulating strip entering said accumulator, a flow diverter for diverting the flow of the strip exiting said accumulator, arranged so as to cross a space delimited by the innermost annular structure of said plurality of concentric annular structures, wherein along the radial direction starting from said axis X one fixed annular structure and one rotating annular structure, adapted to rotate with respect to the axis X, alternate, wherein each rotating annular structure is adapted to rotate, in order to accumulate strip, by an angle less than or equal to 360° in a rotation direction which is opposite to the rotation direction of the rotating annular structure proximal thereto, and wherein each rotating annular structure is adapted to rotate independently of the other rotating annular structures.

Inventors:
BIGONI ANDREA (IT)
Application Number:
PCT/IB2022/060979
Publication Date:
May 25, 2023
Filing Date:
November 15, 2022
Export Citation:
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Assignee:
DANIELI OFF MECC (IT)
International Classes:
B65H20/34; B21C49/00
Foreign References:
US4841317A1989-06-20
JPH10277643A1998-10-20
JPS5924528A1984-02-08
Attorney, Agent or Firm:
CELONA, Antonio et al. (IT)
Download PDF:
Claims:
CLAIMS

1. A metal strip accumulator (1 ) for accumulating a metal strip (2) coming from a production line, said accumulator comprising a plurality of concentric annular structures (3, 4, 5, 6, 7, 8, 9, 10, 11 , 12) with respect to an axis X, for accumulating a metal strip entering said accumulator; said plurality of concentric annular structures comprising both fixed annular structures (3, 5, 7, 9, 11 ) and rotating annular structures (4, 6, 8, 10, 12) adapted to rotate with respect to the axis X; a flow diverter (13) for diverting the metal strip flow exiting said accumulator, said flow diverter being arranged so as to cross an inner space delimited by the innermost annular structure (3) of said plurality of concentric annular structures, wherein, along a radial direction starting from said axis X, one fixed annular structure (3, 5, 7, 9, 11 ) of said fixed annular structures and one rotating annular structure (4, 6, 8, 10, 12) of said rotating annular structures alternate, wherein each rotating annular structure (4, 6, 8, 10, 12) is adapted to rotate, in order to accumulate the strip, by an angle less than or equal to 360° in a rotation direction opposite to the rotation direction of the rotating annular structure which is proximal thereto or of the rotating annular structures which are proximal thereto, and wherein each rotating annular structure (4, 6, 8, 10, 12) is adapted to rotate independently of the other rotating annular structures.

2. An accumulator according to claim 1 , wherein the innermost annular structure (3) is fixed and provided with a deflector roller (14), for deflecting the metal strip towards said flow diverter (13), and with respective containment rollers (15) for containing the strip during the rotation of the rotating annular structure adjacent to said innermost annular structure, said deflector roller and said respective containment rollers having rotation axes parallel to said axis X, wherein each rotating annular structure (4, 6, 8, 10, 12) comprises a respective loop forming roller (17, 18, 19, 20, 21 ) and respective containment rollers (22, 23, 24, 25, 26) having rotation axes parallel to said axis X, and wherein each further fixed annular structure (5, 7, 9, 11 ) comprises respective containment rollers (27, 28, 29, 30) having rotation axes parallel to said axis X, whereby the rotation of each rotating annular structure (4, 6, 8, 10, 12) allows, by means of the respective loop forming roller (17, 18, 19, 20, 21 ), forming a loop on the strip and accumulating the strip along two arcs of a circle joined at one end by said loop, the metal strip accumulated during the rotation of each rotating annular structure being supported by the containment rollers of the rotating annular structure itself and by the containment rollers of the fixed annular structure which is adjacent and internal with respect to said rotating annular structure.

3. An accumulator according to claim 2, wherein each rotating annular structure (4, 6, 8, 10, 12) comprises two first annular plates (31 , 32) parallel to each other and arranged on planes perpendicular to the axis X, and wherein, between said first annular plates, there are provided both the respective loop forming roller (17, 18, 19, 20, 21 ) and said respective strip containment rollers (22, 23, 24, 25, 26), said respective containment rollers having a smaller diameter than said loop forming roller; and wherein each fixed annular structure (3, 5, 7, 9, 11 ) comprises two second annular plates (33, 34) parallel to each other and arranged on said planes perpendicular to the axis X, and wherein, between said second annular plates, there are provided the respective containment rollers (15, 27, 28, 29, 30) having a smaller diameter than said loop forming roller, preferably wherein said second annular plates have a smaller width than the first annular plates.

4. An accumulator according to any one of the preceding claims, wherein at least one fixed support is arranged on at least one side of the accumulator transversely to the axis X, each fixed annular structure (3, 5, 7, 9, 11 ) being integrally fixed to said at least one fixed support, and each rotating annular structure (4, 6, 8, 10, 12) being constrained to said at least one fixed support so as to rotate about the axis X.

5. An accumulator according to claim 4, wherein at least one fixed support is arranged on both sides, opposite to each other, of the accumulator transversely to the axis X.

6. An accumulator according to claim 4, wherein a fixed support (16) is provided for each pair consisting of one fixed annular structure and one rotating annular structure adjacent to each other.

7. An accumulator according to claim 5, wherein a pair of fixed supports (16), arranged symmetrically to a plane orthogonal to the axis X, is provided for each pair consisting of one fixed annular structure and one rotating annular structure adjacent to each other.

8. An accumulator according to any one of claims 4 to 7, wherein each fixed annular structure (3, 5, 7, 9, 11 ) is provided with fastening pins (35) inserted into respective housings (41 ) provided on the fixed support (16); preferably wherein, in the case of a vertical accumulator, said at least one fixed support (16) is arranged in a lower part of the accumulator.

9. An accumulator according to claim 4 or 5, wherein each rotating annular structure (4, 6, 8, 10, 12) is constrained to said at least one fixed support (16), said rotating annular structure being provided, along at least one external lateral periphery thereof, with an annular groove (36) and with a plurality of protruding pins (37), said at least one fixed support being provided, for each rotating annular structure, with

- a respective motor (38) connected to a respective one toothed wheel (39) meshing with part of said protruding pins (37) for transmitting the rotation to the rotating annular structure,

- and at least two idle wheels (40) inserted into said annular groove (36) so as to guide the rotation of the rotating annular structure.

10. An accumulator according to claim 6 or 7, wherein each rotating annular structure (4, 6, 8, 10, 12) is constrained to at least one respective fixed support (16), the rotating annular structure being provided, along at least one external lateral periphery thereof, with an annular groove (36) and with a plurality of protruding pins (37), said at least one respective fixed support (16) being provided with

- a motor (38) connected to a toothed wheel (39) meshing with part of said protruding pins (37) for transmitting the rotation to the corresponding rotating annular structure,

19 - and at least two idle wheels (40) inserted into said annular groove (36) so as to guide the rotation of the corresponding rotating annular structure.

11 . An accumulator according to any one of claims 2 to 10, wherein the outermost annular structure (12) is a rotating structure, wherein, between the innermost annular structure (3) and the outermost annular structure (12), there are provided at least

- a first intermediate rotating annular structure (4),

- a first intermediate fixed annular structure (5),

- a second intermediate rotating annular structure (6),

- a second intermediate fixed annular structure (7), wherein the first intermediate rotating annular structure (4) and the outermost rotating annular structure (12) are adapted to rotate, in a first rotation direction, by an angle less than or equal to 360°, while the second intermediate rotating annular structure (6) is adapted to rotate, in a second rotation direction opposite to the first direction, by an angle less than or equal to 360°.

12. An accumulator according to claim 11 , wherein there are further provided

- a third intermediate rotating annular structure (8),

- a third intermediate fixed annular structure (9),

- a fourth intermediate rotating annular structure (10),

- a fourth intermediate fixed annular structure (11 ), wherein the third intermediate rotating annular structure (8) is adapted to rotate in said first rotation direction by an angle less than or equal to 360°, while the fourth intermediate rotating annular structure (10) is adapted to rotate in said second rotation direction by an angle less than or equal to 360°.

13. An accumulator according to any one of claims 2 to 12, wherein an entry path of the metal strip (2) into the accumulator along a plane containing the axis X, crossing the concentric annular structures perpendicularly to the axis X up to reach the flow diverter (13), is defined by providing for the positioning of the rotating annular structures so that the loop forming rollers (17, 19, 21 ) of the odd rotating annular structures, counting the rotating annular structures starting from said axis X along the radial direction, are arranged at a first side of said plane, while the loop forming rollers (18, 20) of the even annular structures and the

20 deflector roller (14) are arranged at a second side of said plane and tangentially to said plane.

14. A method for accumulating a metal strip coming from a production line by means of an accumulator according to any one of the preceding claims, the method comprising the following stages a) feeding the metal strip into the accumulator along a plane containing the axis X crossing the concentric annular structures perpendicularly to the axis X up to reach the flow diverter (13), b) rotating, when continuously feeding the strip into the accumulator, at least two rotating annular structures (4, 6, 8, 10, 12) by an angle less than or equal to 360°, each rotating annular structure rotating in a rotation direction opposite to the rotation direction of the rotating annular structure which is proximal thereto or of the rotating annular structures which are proximal thereto, whereby each rotating annular structure allows accumulating portions of metal strip with the support of at least one adjacent fixed annular structure (3, 5, 7, 9, 11 ).

15. A method according to claim 14, wherein in stage b) the rotation of one rotating annular structure (4, 6, 8, 10, 12) takes place at least partially at the same time as the rotation of at least one of the remaining rotating annular structures, or wherein in stage b) the rotation of the rotating annular structures (4, 6, 8, 10, 12) takes place one at a time along the radial direction starting from said axis X.

16. A method according to claim 14 or 15, wherein the innermost annular structure (3) is fixed and provided with a deflector roller (14), for deflecting the metal strip towards said flow diverter (13), and with respective containment rollers (15), for containing the strip, said deflector roller (14) and said respective containment rollers (15) having rotation axes parallel to said axis X, wherein each rotating annular structure (4, 6, 8, 10, 12) comprises a respective loop forming roller (17, 18, 19, 20, 21 ) and respective containment rollers (22, 23, 24, 25, 26) having rotation axes parallel to said axis X, wherein each further fixed annular structure (5, 7, 9, 11 ) comprises respective containment rollers (27, 28, 29, 30) having rotation axes parallel to said axis X, wherein, during the rotation of each rotating annular structure (4, 6, 8, 10, 12), the respective loop forming roller (17, 18, 19, 20, 21 ) forms a loop on the strip and

21 allows accumulating the metal strip along two arcs of a circle joined at one end by said loop, the metal strip accumulated during the rotation of each rotating annular structure being supported by the containment rollers of the same rotating annular structure and by the containment rollers of the fixed annular structure which is adjacent and internal with respect to said rotating annular structure.

17. A method according to claim 16, wherein, in stage a) a positioning of the rotating annular structures is provided so that the loop forming rollers (17, 19, 21 ) of the odd rotating annular structures, counting the rotating annular structures from said axis X along the radial direction, are arranged at a first side of said plane, while the loop forming rollers (18, 20) of the even rotating annular structures and the deflector roller (14) are arranged at a second side of said plane and tangentially to said plane, whereby an entry path of the metal strip into the accumulator is defined along the plane containing the axis X.

22

Description:
METAL STRIP ACCUMULATOR AND STRIP ACCUMULATING METHOD THEREOF

Field of the invention

The present invention relates to a metal strip accumulator for accumulating a strip coming from a production line.

Background art

Different types of metal strip accumulators are known, e.g. of the vertical or horizontal type.

In the field of iron and steel, and in particular in the field of rolling and finishing flat cold-rolled products, it is often necessary to accumulate great quantities of metal strip between one production line and the next one, which can normally operate a different speed from each other, as is the case, for example, between a pickling line and a galvanizing/painting line.

These accumulators are usually developed in height and very bulky. They are also costly in terms of the structures for housing the same, besides being difficult to maintain and control by operators who must cover several meters of ramps of stairs.

In other cases, for example, when an accumulator must be inserted into an existing system layout, it may be necessary to build a special warehouse, with an increase in volume and costs.

Thus, the need is felt for an innovative accumulator, which is compact and functional, capable of overcoming the aforesaid drawbacks.

Summary of the invention

It is an object of the present invention to make an accumulator, preferably developed on a vertical plane, which, despite being capable of accumulating considerable amounts of strip, has a significantly reduced volume with respect to known accumulators.

It is another object of the present invention to make a compact accumulator capable of accumulating the strip during a continuous advancing thereof.

It is a further object of the present invention to make a particularly effective operating method of the aforesaid accumulator. The present invention achieves at least one of such objects, and other objects which will be apparent in the light of the present description, by means of a metal strip accumulator for accumulating a metal strip coming from a production line, said accumulator comprising a plurality of concentric annular structures with respect to an axis X, for accumulating a metal strip entering said accumulator; said plurality of concentric annular structures comprising both fixed annular structures and rotating annular structures adapted to rotate with respect to the axis X; a flow diverter for diverting the flow of the metal strip exiting said accumulator, the flow diverter being arranged so as to cross an inner space delimited by the innermost annular structure of said plurality of concentric annular structures, wherein, along a radial direction starting from said axis X, one fixed annular structure of said fixed annular structures and one rotating annular structure of said rotating annular structures alternate; wherein each rotating annular structure is adapted to rotate, in order to accumulate the strip, by an angle less than or equal to 360° in a rotation direction opposite to the rotation direction of the rotating annular structure which is proximal thereto or of the rotating annular structures which are proximal thereto, and wherein each rotating annular structure is adapted to rotate independently of the other rotating annular structures.

A further aspect of the invention regards a method for accumulating a metal strip coming from a production line by means of the aforesaid accumulator, the method comprising the following steps a) feeding a metal strip into the accumulator along a plane containing the axis X crossing the concentric annular structures perpendicularly to the axis X until reaching the flow diverter, b) rotating, when continuously feeding the strip into the accumulator, at least two rotating annular structures by an angle less than or equal to 360°, each rotating annular structure rotating in a rotation direction opposite to the rotation direction of the rotating annular structure which is proximal thereto or of the rotating annular structures which are proximal thereto, whereby each rotating annular structure allows accumulating portions of metal strip with the support of at least one adjacent fixed annular structure.

Further advantages of the solution of the invention are:

- the modularity of the accumulator, being able to increase or decrease the concentric annular structures in order to increase or decrease the potential strip accumulation capacity;

- the independence of the rotation controls of the rotating annular structures, which rotate alternately to one another clockwise and anti-clockwise, compensating the respective movements to satisfy the production needs in shorter times, also by virtue of an automation that manages the tension control procedure;

- the fact that the strip, during the accumulation thereof, is always supported and opportunely guided, avoiding qualitative damage or yielding.

Further features and advantages of the invention will become more apparent in the light of the detailed description of exemplary, but non-exclusive, embodiments.

The dependent claims describe particular embodiments of the invention.

Brief description of the drawings

In the description of the invention reference is made to the accompanying drawings, which are provided by way of non-limiting example, in which:

Figure 1 represents a perspective view of an example of an accumulator according to the invention;

Figure 2 represents a side view of part of a system layout comprising two accumulators according to the invention;

Figure 3 represents a perspective view of a first component of the accumulator according to the invention;

Figure 4 shows an enlargement of part of the view in Figure 3;

Figure 5 represents a perspective view of a second component of the accumulator according to the invention;

Figure 6 represents a perspective view of a third component of the accumulator according to the invention;

Figure 7 represents a partial cross-sectional view of said third component;

Figures 8 and 9 represent partially sectional side views, in which only some details of said third component are visible; Figure 10 represents a partial sectional side view of the accumulator in which the entry path of the strip is visible in an initial operating step;

Figure 11 represents a partial perspective view of the accumulator in which the entry and outlet of the strip is visible when the accumulation thereof is not provided;

Figure 12 represents a succession of the movement of a first concentric annular structure of the accumulator;

Figure 13 represents a succession of the movement of a second concentric annular structure of the accumulator;

Figure 14 represents a partial sectional side view of the accumulator in which the maximum accumulation of strip obtained from the first rotating concentric annular structure is visible;

Figure 15 represents partial sectional side view of the accumulator in which the maximum accumulation of strip obtained from the first rotating concentric annular structure and from the second rotating concentric annular structure is visible.

The same reference numerals and letters in the drawings identify the same elements or components.

Description of exemplary embodiments of the invention

With reference to the Figures, some examples of a metal strip accumulator for accumulating a metal strip coming from a production line are shown.

In all embodiments of the invention, the accumulator comprises (Figures 1 , 8, I Q- 11 ):

- a plurality of concentric annular structures 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12 with respect to an axis X, e.g. six or eight or ten in number, for accumulating a metal strip entering the accumulator,

- a flow diverter 13 for diverting, preferably by 90°, the metal strip flow exiting the accumulator, the diverter being arranged so as to cross a central space delimited by the innermost annular structure 3 of said plurality of concentric annular structures.

For example, the flow diverter 13 defines a longitudinal axis inclined by an angle of about 40°-50° with respect to the axis X, preferably equal to 45°. In the case of a vertical accumulator, both of these axes are horizontal, preferably skewed axes.

The plurality of concentric annular structures comprises both fixed annular structures 3, 5, 7, 9, 11 and rotating annular structures 4, 6, 8, 10, 12 adapted to rotate with respect to the axis X.

Advantageously, along the radial direction starting from the axis X, one fixed annular structure 3, 5, 7, 9, 11 of said concentric annular structures and one rotating annular structure 4, 6, 8, 10, 12 of said concentric annular structures alternate.

In other words, the fixed annular structures 3, 5, 7, 9, 11 and the rotating annular structures 4, 6, 8, 10, 12 are arranged alternatively along the radial direction starting from the axis X.

Preferably, at least two fixed annular structures and at least two rotating annular structures are arranged alternatively along the radial direction starting from the axis X.

As shown in Figures 3 and 4, the fixed annular structures and the rotating annular structures are preferably closed ring structures, i.e. circular.

Each rotating annular structure 4, 6, 8, 10, 12 is adapted to rotate with respect to the axis X, in order to accumulate the strip therein, by an angle less than or equal to 360° in a rotation direction opposite to the rotation direction of the rotating annular structure which is proximal thereto or of the rotating annular structures which are proximal thereto. Thus, it is possible to accumulate a considerable amount of strip with a highly reduced space requirement.

One further advantage is represented by the fact that each rotating annular structure 4, 6, 8, 10, 12 is adapted to rotate independently of the other rotating annular structures. The independence of the rotation controls of the rotating annular structures and the automation thereof allows compensating the respective movements for satisfying the production needs in shorter times.

An accumulator of the vertical type, with the axis X horizontal, is shown in the Figures. However, the present invention can also be actuated by means of an accumulator arranged horizontally, i.e. with the axis X vertical, cooperating with entry and outlet diverters. The innermost annular structure 3 is preferably fixed and provided with a deflector roller 14, for deflecting the metal strip towards the flow diverter 13, and with respective containment rollers 15 (Figure 10) for containing the strip during the rotation of the rotating annular structure 4 adjacent to said innermost annular structure (Figure 12 or 14), said deflector roller 14 and said respective containment rollers 15 having rotation axes parallel to said axis X.

Each rotating annular structure 4, 6, 8, 10, 12 comprises a respective loop forming roller 17, 18, 19, 20, 21 and respective containment rollers 22, 23, 24, 25, 26 having rotation axes parallel to said axis X (Figure 10).

Each further fixed annular structure 5, 7, 9, 11 comprises respective containment rollers 27, 28, 29, 30 having rotation axes parallel to said axis X (Figure 10).

With this configuration, the rotation of each rotating annular structure 4, 6, 8, 10, 12 allows, by means of the respective loop forming roller 17, 18, 19, 20, 21 , forming a loop on the strip (Figures 12 and 13) and accumulating the strip along two arcs of a circle, which are preferably but not necessarily concentric, joined at one end by said loop (Figures 12-15), and the metal strip accumulated during the rotation of each rotating annular structure is supported by the containment rollers of the rotating annular structure itself and by the containment rollers of the fixed annular structure which is adjacent and internal with respect to said rotating annular structure.

The diameter of the loop forming rollers is compatible with the thickness of the strip that will be wound, e.g. a diameter varying in a range comprised between 600 mm and 1200 mm.

In one variant, each rotating annular structure 4, 6, 8, 10, 12 comprises, or consists of, two first annular plates 31 , 32 (see for example in Figure 3), which are parallel to each other and arranged on planes perpendicular to the axis X.

Both the respective loop forming roller 17, 18, 19, 20, 21 and the respective containment rollers 22, 23, 24, 25, 26 of the strip are provided between the two first annular plates 31 , 32, opportunely spaced apart from each other by a distance which is greater than the minimum width of the strip to be accumulated, said containment rollers having a smaller diameter than the loop forming roller. A plurality of flat reinforcing transversal elements 50 can be provided between the two annular plates 31 , 32.

Figure 3 shows, for example, the rotating annular structure 4 provided with the loop forming roller 17 and with a plurality of containment rollers 22.

Similarly, each fixed annular structure 3, 5, 7, 9, 11 comprises two second annular plates 33, 34 parallel to each other and arranged on the aforesaid planes perpendicular to the axis X (see example in Figure 5).

Between the two second annular plates 33, 34, also opportunely spaced apart from each other by a distance which is greater than the minimum width of the strip to be accumulated, only the respective containment rollers 15, 27, 28, 29, 30 are provided, preferably having a diameter which is substantially equal to the diameter of the containment rollers of the first annular plates 31 , 32.

A plurality of flat reinforcing transversal elements 51 can also be provided between the two annular plates 33, 34.

The second annular plates 33, 34 preferably have a width which is smaller than the first annular plates 31 , 32.

Figure 5 shows, for example, the fixed annular structure 5 provided with a plurality of containment rollers 27.

In a first embodiment of the invention at least one fixed support, e.g., only one fixed support, is arranged on only one side of the accumulator transversely to the axis X. Each fixed annular structure 3, 5, 7, 9, 11 is integrally fixed to said at least one fixed support, and each rotating annular structure 4, 6, 8, 10, 12 is constrained to said at least one fixed support so as to rotate about the axis X.

In a second embodiment of the invention at least one fixed support, e.g., only one fixed support, is arranged on both sides, opposite to each other, of the accumulator transversely to the axis X.

In one variant of said first embodiment, a fixed support 16 is provided for each pair consisting of one fixed annular structure and one rotating annular structure adjacent to each other (Figure 1 ).

In one variant of said second embodiment, there is provided a pair of fixed supports 16, arranged symmetrically to a plane orthogonal to the axis X, for each pair consisting of one fixed annular structure and one rotating annular structure adjacent to each other (Figure 2).

In the case of a vertical accumulator, such as the one shown in the Figures, the single fixed support or the plurality of fixed supports 16 are preferably arranged in a lower part of the accumulator.

Preferably, each fixed annular structure 3, 5, 7, 9, 11 is provided with fastening pins 35 (Figure 5) inserted into respective housings 41 provided on said at least one fixed support. In the case of a vertical accumulator, for example, the fastening pins 35 are arranged externally along a lower portion of the fixed annular structures.

In the case of a single fixed support arranged, transversely to the axis X, on both sides, opposite to each other, of the accumulator, each fixed annular structure 3, 5, 7, 9, 11 is provided with fastening pins 35, on both the annular plates 33, 34 (Figure 5), inserted into respective housings 41 provided on the two fixed supports.

Each rotating annular structure 4, 6, 8, 10, 12 is constrained to the two fixed supports as it is provided, along both external side peripheries thereof, e.g. externally on both the annular plates 31 , 32, with an annular groove 36 and with a plurality of protruding pins 37, preferably arranged radially outside the respective annular groove 36 (Figures 3-4).

Both the fixed supports can be provided for each rotating annular structure with (Figures 6-7)

- a respective motor 38 connected to a respective toothed wheel 39 meshing with part of said protruding pins 37 for transmitting the rotation to the rotating annular structure (Figure 8),

- and at least two idle wheels 40 inserted into said annular groove 36 so as to guide the rotation of the rotating annular structure (Figure 9).

In the case of a single fixed support arranged, transversely to the axis X, on only one side of the accumulator, each fixed annular structure 3, 5, 7, 9, 11 is provided with fastening pins 35, e.g. only on the annular plate 34 or 33, inserted into respective housings 41 provided on said single fixed support. Each rotating annular structure 4, 6, 8, 10, 12 is constrained to said single fixed support as it is provided along an external lateral periphery thereof, e.g. externally on the annular plate 31 or 32, with an annular groove 36 and with a plurality of protruding pins 37, preferably arranged radially outside said annular groove 36.

The single fixed support can be provided for each rotating annular structure with

- a respective motor 38 connected to a respective toothed wheel 39 meshing with part of said protruding pins 37 for transmitting the rotation to the rotating annular structure,

- and at least two idle wheels 40 inserted into said annular groove 36 so as to guide the rotation of the rotating annular structure.

In the case of a plurality of fixed supports 16 arranged, transversely to the axis X, on only one side of the accumulator, in particular one fixed support 16 for each pair consisting of one fixed annular structure and one rotating annular structure adjacent to each other, each fixed annular structure 3, 5, 7, 9, 11 is provided with fastening pins 35, e.g. only on the annular plate 34 or 33, inserted into respective housings 41 of the respective fixed support 16.

Each rotating annular structure 4, 6, 8, 10, 12 is constrained to the respective fixed support 16 as it is provided along at least one external lateral periphery thereof, e.g. externally on the annular plate 31 or 32, with an annular groove 36 and with a plurality of protruding pins 37, preferably arranged radially outside the respective annular groove 36.

Each fixed support 16 can be provided with

- a motor 38 connected to a toothed wheel 39 meshing with part of said protruding pins 37 for transmitting the rotation to the corresponding rotating annular structure,

- and at least two idle wheels 40 inserted into said annular groove 36 so as to guide the rotation of the corresponding rotating annular structure.

In the case of a plurality of fixed supports 16 arranged, transversely to the axis X, on both sides, opposite to each other, of the accumulator, in particular in the case of a pair of fixed supports 16, arranged symmetrically to a plane orthogonal to the axis X, for each pair consisting of one fixed annular structure and one rotating annular structure adjacent to each other, each fixed annular structure 3, 5, 7, 9, 11 is provided with fastening pins 35, on both the annular plates 33, 34 (Figure 5), inserted into respective housings 41 of the two respective fixed supports 16 (Figure 6).

Each rotating annular structure 4, 6, 8, 10, 12 is constrained to the two respective fixed supports 16 as it is provided along both the external side peripheries thereof, e.g. externally on both the annular plates 31 , 32, with an annular groove 36 and with a plurality of protruding pins 37, preferably arranged radially outside the respective annular groove 36 (Figures 3-4).

Each fixed support 16 on both sides of the accumulator can be provided with (Figures 6-7)

- a motor 38 connected to a toothed wheel 39 meshing with part of said protruding pins 37 for transmitting the rotation to the corresponding rotating annular structure (Figure 8),

- and at least two idle wheels 40 inserted into said annular groove 36 so as to guide the rotation of the corresponding rotating annular structure (Figure 9).

A further advantage of the accumulator of the invention is represented by the modularity thereof. In fact, it is possible to increase or decrease the concentric annular structures to increase or decrease the potential strip accumulation capacity.

In a first example (not shown) the accumulator consists of six concentric annular structures. Between the innermost annular structure 3, which is fixed, and the outermost annular structure 12, which is rotating, there are provided, along the radial direction starting from the fixed annular structure 3:

- a first intermediate rotating annular structure 4,

- a first intermediate fixed annular structure 5,

- a second intermediate rotating annular structure 6,

- a second intermediate fixed annular structure 7.

The first intermediate rotating annular structure 4 and the outermost rotating annular structure 12 are adapted to rotate, in a first rotation direction, by an angle less than or equal to 360°, while the second intermediate rotating annular structure 6 is adapted to rotate, in a second rotation direction, opposite to the first direction, by an angle less than or equal to 360°. In a second example (not shown) the accumulator consists of eight concentric annular structures. Between the innermost annular structure 3, which is fixed, and the outermost annular structure 12, which is rotating, there are provided, along the radial direction starting from the fixed annular structure 3:

- a first intermediate rotating annular structure 4,

- a first intermediate fixed annular structure 5,

- a second intermediate rotating annular structure 6,

- a second intermediate fixed annular structure 7,

- a third intermediate rotating annular structure 8,

- a third intermediate fixed annular structure 9.

The first intermediate rotating annular structure 4 and the third intermediate rotating annular structure 8 are adapted to rotate, in a first rotation direction, by an angle less than or equal to 360°, while the second intermediate rotating annular structure 6 and the outermost rotating annular structure 12 are adapted to rotate, in a second rotation direction opposite to the first direction, by an angle less than or equal to 360°.

In a third example, shown in Figure 1 , the accumulator consists of ten concentric annular structures. Between the innermost annular structure 3, which is fixed, and the outermost annular structure 12, which is rotating, there are provided, along the radial direction starting from the fixed annular structure 3:

- a first intermediate rotating annular structure 4,

- a first intermediate fixed annular structure 5,

- a second intermediate rotating annular structure 6,

- a second intermediate fixed annular structure 7,

- a third intermediate rotating annular structure 8,

- a third intermediate fixed annular structure 9,

- a fourth intermediate rotating annular structure 10,

- a fourth intermediate fixed annular structure 11 .

The first intermediate rotating annular structure 4, the third intermediate rotating annular structure 8 and the outermost rotating annular structure 12 are adapted to rotate, in a first rotation direction, by an angle less than or equal to 360°, while the second intermediate rotating annular structure 6 and the fourth intermediate rotating annular structure 10 are adapted to rotate, in a second rotation direction opposite to the first direction, by an angle less than or equal to 360°.

Should it be necessary to accumulate even greater lengths of strip, it cannot be excluded providing an accumulator consisting of twelve or more concentric annular structures.

Instead, if it were sufficient to accumulate minimum amounts of strip, it cannot be excluded providing an accumulator consisting of only four concentric annular structures. Between the innermost annular structure 3, which is fixed, and the outermost annular structure 12, which is rotating, there are provided along the radial direction starting from the fixed annular structure 3:

- an intermediate rotating annular structure 4,

- an intermediate fixed annular structure 5.

The intermediate rotating annular structure 4 is adapted to rotate, in a first rotation direction, by an angle less than or equal to 360°, while the outermost rotating annular structure 12 is adapted to rotate, in a second rotation direction opposite to the first direction, by an angle less than or equal to 360°.

Figure 2 shows an example in which the vertical encumbrance of the accumulator is further reduced as it is partially accommodated inside a cavity of the system foundations.

In particular, Figure 2 shows a side view of part of a system layout comprising two accumulators according to the invention, arranged at 90° with respect to each other and at a short distance from each other. Advantageously, this configuration allows connecting two production lines close to each other, substantially parallel to each other. In fact, the presence of a flow diverter inside each accumulator of the invention allows diverting the flow of the strip twice by 90°.

In all embodiments of the accumulator of the invention, in the initial step of entry of the metal strip 2, there is provided an entry path in the accumulator along a plane containing the axis X, crossing the concentric annular structures perpendicularly to the axis X until reaching the flow diverter 13 (Figures 10, 11 ).

Such entry path is defined providing the positioning of the rotating annular structures so that the loop forming rollers of the odd rotating annular structures, counting the rotating annular structures starting from said axis X along the radial direction, are arranged at a first side, e.g. at the top, with respect to said entry plane, and so that the loop forming rollers of the even rotating annular structures and the deflector roller 14 are arranged at the bottom and tangentially to said entry plane.

In particular, in the example in Figure 10, the loop forming rollers 17, 19, 21 of the odd rotating annular structures are arranged at the top of the entry plane of the strip, while the loop forming rollers 18, 20 of the even rotating annular structures and the deflector roller 14 are arranged at a second side, e.g. at the bottom, and tangentially to said entry plane.

Hereinafter a method is described for accumulating a metal strip coming from a production line by means of an accumulator according to the invention.

Such method, in all embodiments of the accumulator, comprises the following steps a) feeding a metal strip into the accumulator along an entry plane containing the axis X crossing the concentric annular structures perpendicularly to the axis X until reaching the flow diverter 13, b) rotating, when continuously feeding the strip into the accumulator, at least two rotating annular structures 4, 6, 8, 10, 12 by an angle less than or equal to 360°, each rotating annular structure rotating in a rotation direction opposite to the rotation direction of the rotating annular structure which is proximal thereto, or of the rotating annular structures which are proximal thereto, whereby each rotating annular structure allows accumulating portions of metal strip with the support of at least one adjacent fixed annular structure 3, 5, 7, 9, 11 .

In step a) there is provided the positioning of the rotating annular structures so that the loop forming rollers 17, 19, 21 of the odd rotating annular structures, counting the rotating annular structures starting from said axis X along the radial direction, are arranged at the top of said entry plane, while the loop forming rollers 18, 20 of the even rotating annular structures and the deflector roller 14 are arranged at the bottom and tangentially to said entry plane, whereby an entry path of the metal strip is defined in the accumulator along the entry plane containing the axis X. In a first variant of the method, in step b) the rotation of the rotating annular structures 4, 6, 8, 10, 12 occurs one at a time along the radial direction starting from said axis X.

In a second variant of the method, in step b) the rotation of one rotating annular structure 4, 6, 8, 10, 12 occurs partially at the same time, or at the same time as the rotation of at least one of the other rotating annular structures.

In general, during the rotation of each rotating annular structure, the respective loop forming roller forms a loop on the strip and allows metal strip to be accumulated along two arcs of a circle joined at one end by said loop, the metal strip accumulated during the rotation of each rotating annular structure being supported by the containment rollers of the rotating annular structure itself and by the containment rollers of the fixed annular structure, which is adjacent and internal with respect to said rotating annular structure.

With reference to the Figures 10-13, the first variant of the method of the invention is described hereinafter.

In the initial step (step a - Figures 10-11 ) the metal strip 2 crosses the concentric annular structures along the entry plane perpendicularly to the axis X and reaches the flow diverter 13 diverting the strip by 90°. In this step, the strip 2 only touches the lower loop forming rollers 18, 20 and the deflector roller 14. The upper loop forming rollers 17, 19, 21 are placed at such a distance that they are not touched by the strip.

Should it not be necessary to accumulate the strip, the configuration of Figures 10 and 11 can be maintained and the strip advances continuously without being wound in the concentric annular structures.

When the operating conditions exist whereby the system needs to accumulate strip, the intermediate rotating annular structure 4 starts to rotate in a first rotation direction, always with the strip advancing and under tension (Figure 12).

The loop forming roller 17 touches the strip, forms the loop and will drag the strip during the rotation. The torque needed for the rotation of the intermediate rotating annular structure 4 must be greater than the resultant of the tension of the strip in all rotation steps. With reference to Figure 12, when the intermediate rotating annular structure 4 starts rotating, the strip first comes into contact with a containment roller 27 of the intermediate fixed annular structure 5 (Figure 12a).

The loop is generated by the loop forming roller 17 by virtue of the contact of the strip with the containment roller 27 and with the deflector roller 14 (Figure 12b).

As the rotation continues, because of the tension due to the rotation, the strip comes into contact with the containment rollers 15 of the innermost fixed annular structure 3 and with the containment rollers 22 of the same intermediate rotating annular structure 4 (Figures 12c-12e). The strip continues advancing, i.e. being fed, during the rotation of the intermediate rotating annular structure 4.

Figure 14 shows a partial sectional side view of the accumulator, in which the maximum accumulation of strip obtained from the rotating annular structure 4 is visible. As can be seen, two almost complete concentric circles have been created, with an important accumulation of strip which can be equal, by way of example, to about 40 meters considering a diameter of the loop forming roller 17 equal to 600 mm and a diameter of the rotating annular structure 4 of about 7200 mm.

After reaching the maximum accumulation in the rotating annular structure 4, according to the first method variant, the intermediate rotating annular structure 6 starts to rotate in a second rotation direction, opposite to said first direction, always with the strip under tension (Figure 13).

The loop forming roller 18 touches the strip, forms the loop and will drag the strip during the rotation. Also in this case, the torque needed for the rotation of the intermediate rotating annular structure 5 must be greater than the resultant of the tension of the strip in all rotation steps.

With reference to Figure 13, when the intermediate rotating annular structure 5 starts to rotate, firstly the strip comes into contact with a containment roller 28 of the intermediate fixed annular structure 7 (Figure 13a).

The loop is generated by the loop forming roller 18 by virtue of the contact of the strip with the aforesaid containment roller 28 of the intermediate fixed annular structure 7 and with the aforesaid containment roller 27 of the intermediate fixed annular structure 5 (Figure 13b). As the rotation continues, because of the tension due to the rotation, the strip comes into contact with the other containment rollers 27 of the intermediate fixed annular structure 5 and with the containment rollers 23 of the same intermediate rotating annular structure 6 (Figures 13d-13e). The strip continues advancing, i.e. being fed, also during the rotation of the intermediate rotating annular structure 6.

Figure 15 shows a partial sectional side view of the accumulator, in which the maximum accumulation of strip obtained from the rotating annular structure 4 and from the rotating annular structure 6 is visible.

As in the above description, according to the first method variant, the intermediate rotating annular structure 8, the intermediate rotating annular structure 10, and the outer rotating annular structure 12 are rotating one after the other.

Instead, in the second method variant, in step b) the rotation of one rotating annular structure 4, 6, 8, 10, 12 occurs partially at the same time, or at the same time as the rotation of at least another of the remaining rotating annular structures. All the rotating annular structures could also rotate at least partially at the same time. This second variant can allow the production needs to be satisfied in shorter times.