WO2025181679A1

WO2025181679A1 - Apparatus for feeding pieces of a sheet material and method for feeding pieces of a sheet material

Info

Publication number: WO2025181679A1
Application number: PCT/IB2025/052033
Authority: WO
Inventors: Giacomo Noferini
Original assignee: GD SpA
Current assignee: GD SpA
Priority date: 2024-03-01
Filing date: 2025-02-26
Publication date: 2025-09-04
Anticipated expiration: 2026-09-01

Abstract

An apparatus (1) for feeding pieces of a sheet material, comprising a first roller (35) rotatable about a first transverse axis (T1); a second roller (55) rotatable about a second transverse axis (T2) parallel to, and longitudinally spaced from, said first transverse axis (T1) at least one conveyor belt (60) wound along a closed path around said first roller (35) and said second roller (55), said conveyor belt (60) defining a conveying surface (63) longitudinally extended from a first end (64) located at said first roller (35) to a second end (65) located at said second roller (55) and configured to convey a piece of sheet material from a receiving position (63a) to a feeding position (63b) longitudinally spaced from said receiving position (63a) towards said second end (65); wherein said conveyor belt (60) comprises at least one engagement portion (61) extended along said closed path, and wherein: said first roller (35) is translatable along said first transverse axis (T1) between a plurality of stable positions and comprises at least one guide portion (36) extended around said first transverse axis (T1) and arranged in engagement with said engagement portion (61) such that a transverse translation of said first roller (35) results in a corresponding transverse translation of the first end (64) of the conveying surface (63); and/or said second roller (55) is translatable along said second transverse axis (T2) between a plurality of stable positions and comprises at least one guide portion (56) extended around said second transverse axis (T2) and arranged in engagement with said engagement portion (61) such that a transverse translation of said second roller (55) results in a corresponding transverse translation of said second end (65) of the conveying surface (63).

Description

“Apparatus for feeding pieces of a sheet material and method for feeding pieces of a sheet material”

The present invention refers to an apparatus for feeding pieces of a sheet material and a method thereof. In particular, the present invention involves transporting a sheet material from a receiving position affected by a margin of error to a preset feeding position.

Without loss of generality, the present invention may find application in a production line for electrochemical cells. In particular, the present invention can be used to make secondary batteries or capacitors, comprising planar electrodes separated from each other by a dielectric separator.

In the industrial sector of the production of some types of electrical accumulators, such as for example lithium batteries made of “pouch” type cells, electrochemical cells are made from stacks of positive and negative electrode precursors in the form of pieces of a sheet material, arranged alternately on top of each other, with a separation layer made of dielectric material interposed between them, generally indicated in the technical jargon of the sector with the term “separator”.

The electrode precursors are substantially made by depositing a layer of electrode active material on one surface or on both surfaces of a current collector metal foil. By choosing an appropriate combination of electrode active material and current collector metal foil material, electrode precursors intended to make positive electrodes and electrode precursors intended to make negative electrodes can be obtained.

The metal foils forming the electrode precursors are then cut into pieces in the form of usually square or rectangular sheets of preset dimensions (corresponding to the dimensions that the electrolytic cell must have) from respective coils of positive and negative electrode precursor that have been previously sectioned into strips of width substantially equal to one of the dimensions of the electrode precursor foils.

Similarly, the separator sheets are cut into square or rectangular sheets of preset dimensions from respective separator coils that have been previously sectioned into strips of width substantially equal to one of the dimensions of the separator sheets.

The pieces of positive electrode precursor thus obtained are temporarily stored (very often by stacking them one on top of the other), as well as the pieces of negative electrode precursor and the separator sheets are temporarily stored (very often by stacking them one on top of the other).

The electrochemical cells are made by stacking the pieces of positive and negative electrode precursor in a stacking area, by arranging them on top of each other alternately and separated from each other by the separators. The separators can be made from a plurality of individual separator sheets or from a single separator sheet folded in such a way that individual portions of the separator sheet are interposed between each pair of positive and negative electrodes (so-called “z-folding").

This operation is repeated by stacking as many stacking groups on top of each other as necessary in order to obtain the desired electrical characteristics of the electrolytic cell. By adding an electrolyte to the stacking group, ions can migrate between anode and cathode transforming the electrode precursors into electrodes and the electrochemical cell into a battery.

In the experience of the Applicant, the precise positioning of the pieces of electrode precursor in the stacking area is important to ensure the quality and safety of the electrolytic cell.

The Applicant has found that stacking can be carried out by means of a stacking member, for example of the suctioned type, which picks up a piece of electrode precursor from a feeding position and, following a preset trajectory, arranges it in the stacking area.

The Applicant has found that, if the position of the precursor electrode piece in the feeding position is preset and relatively precise, the transfer from the feeding position to the stacking area can be made by means of relatively simple kinematics following a preset trajectory, which would allow the precursor electrode piece to be positioned in the stacking area quickly and accurately. Adopting a feedback control on the movement of the stacking member could also be potentially avoided.

The Applicant has verified that the pieces of electrode precursor transported towards the feeding position from previous processing stations, for example by means of conveyors, are often affected by a margin of error on the respective position, which if transferred to the stacking area following a preset trajectory, would be transformed into a positioning error in the substantially corresponding stacking area.

The present invention therefore concerns, in a first aspect thereof, an apparatus for feeding a sheet material.

Preferably, a first roller rotatable about a first transverse axis is provided.

Preferably, a second roller is provided. The second roller is rotatable about a second transverse axis parallel to, and longitudinally spaced from, said first transverse axis.

Preferably, at least one conveyor belt wound along a closed path around said first roller and second roller is provided.

Preferably, said conveyor belt defines a transport surface extended longitudinally from a first end located at said first roller to a second end located at said second roller and configured to transport a piece of sheet material from a receiving position to a feeding position spaced longitudinally from said receiving position towards said second end.

Preferably, said conveyor belt comprises at least one engagement portion extended along the closed path.

In one embodiment, said first roller is translatable along said first transverse axis between a plurality of stable positions and comprises at least one guide portion extended around said first transverse axis and arranged in engagement with said engagement portion so that a transverse translation of said first roller results in a corresponding transverse translation of the first end of the transport surface.

Preferably, said first roller is translatable independently with respect to said second roller.

In one embodiment, said second roller is translatable along said second transverse axis between a plurality of stable positions and comprises at least one guide portion extended around said second transverse axis and arranged in engagement with said engagement portion so that a transverse translation of said second roller results in a corresponding transverse translation of the second end of the transport surface.

Preferably, said second roller is translatable independently with respect to said first roller. In a non-exclusive embodiment, the first roller and the second roller are translatable respectively along the first transverse axis and the second transverse axis independently of each other.

In a different non-exclusive embodiment, the first roller is translatable along the respective first transverse axis and the second roller is not translatable along the respective second transverse axis.

In a further different non-exclusive embodiment, the first roller is not translatable along the respective first transverse axis and the second roller is translatable along the respective second transverse axis.

The present invention concerns, in a second aspect thereof, a method for feeding a sheet material.

Preferably, an apparatus is provided according to the first aspect.

Preferably, a piece of sheet material is transported from the receiving station to the feeding station.

Preferably, if the piece in the receiving position has an orientation other than a preset feeding orientation and/or if the receiving position is transversely offset from a preset feeding position, said first roller is translated along said first transverse axis and/or said second roller is translated along said second transverse axis.

The Applicant has verified that by transversely translating the first roller and/or the second roller, the conveyor belt, and the transport surface defined on it, are locally dragged in a transverse direction at the first end and the second end.

The first and second end can be moved transversely in a differential manner, for example by transversely translating the first roller while keeping the second roller transversely stationary, or by transversely translating the second roller while keeping the first roller transversely stationary, or by transversely translating both the first and second roller differently with respect to each other. By moving the first and second end transversely in a differential manner, a rotation of the transport surface with respect to an axis perpendicular to the transport surface is obtained. If the piece of sheet material is received in the receiving station with an orientation other than the preset one, the transport surface can be rotated by transversely translating the first and/or the second roller to bring the piece of sheet material to the preset orientation.

The first and second end can be moved transversely in a concordant manner, by transversely translating both the first and second roller equally. By moving the first and second end equally transversely, a uniform translation of the transport surface in the transverse direction is obtained. If the piece of sheet material is received in the receiving station with a transverse position other than the preset one, the transport surface can be translated by transversely moving the first and second roller to bring the piece of material into the preset transverse position.

If the piece of sheet material is received in the receiving station with a transverse position and orientation both other than the preset ones, the transport surface can be translated and rotated by transversely moving the first and/or the second roller by respective distances determined on the basis of the desired translation and rotation.

By “piece of sheet material” is meant a flat object having two dimensions much larger than a third dimension, for example at least two orders of magnitude, preferably at least four. The piece of sheet material may be an electrode precursor and may be a single-piece plate, or a plate formed by a plurality of layers joined together of identical material or of different materials.

The transport surface is configured to transport a piece of sheet material from the receiving position to the feeding position. By “to transport/transporting a piece of sheet material”, and similar expressions, it is meant to displace the piece of sheet material and to stably support the piece of sheet material by contrasting its weight, preferably substantially for the entire duration of the displacement. This allows the speed and position of the piece of sheet material to be varied and adjusted accurately while it is being displaced between the receiving position and the feeding position, for example by translating the first roller and/or the second roller or by adjusting the speed from the transport surface during the transport.

The piece of sheet material is received on the transport surface in the receiving position. The receiving position may have a margin of error of the order of magnitude of one-tenth of a millimetre, millimetre or centimetre. By “receiving position” it is meant the area of the transport surface where the piece is received, potentially affected by the margin of error.

The transport surface is movable longitudinally by advancing the conveyor belt along the closed path. By “longitudinal direction” is meant a direction parallel to the direction of movement of the transport surface when the conveyor belt is advanced along the closed path without translating the first roller and the second roller.

Terms such as “longitudinal”, “longitudinally” and the like are used with reference to directions parallel to the longitudinal direction or to magnitudes measured parallel to the longitudinal direction.

By “transverse direction” is meant a direction perpendicular to the longitudinal direction and parallel to the transport surface.

Terms such as “transverse”, “transversely” and the like are used with reference to directions parallel to the longitudinal direction or to magnitudes measured parallel to the longitudinal direction.

Preferably, the piece of sheet material is transported onto the transport surface in a feeding position.

Preferably, the piece of sheet material is transportable on the transport surface from the receiving position to the feeding position.

Preferably, the transport surface is configured to support the piece of sheet material while transporting the piece of sheet material from the receiving position to the feeding position.

In a non-exclusive embodiment, the piece of sheet material is rested on the transport surface while the transport surface transports the piece of sheet material from the receiving position to the feeding position.

By feeding position it is meant a position longitudinally distanced from the pickup position in which the piece can be fed to, or picked up by, a generic mechanical member of known type.

The feeding position is preset and has a margin of error lower than the margin of error of the receiving position by at least one order of magnitude, preferably by at least two orders of magnitude.

By preset it is meant a position decided a priori that does not depend on the receiving position of the piece.

By “transversely offset from” it is meant not aligned along a longitudinal axis. By “transversely aligned” it is meant aligned along a longitudinal axis.

The first roller may be translatable along the first transverse axis between a plurality of stable positions. Similarly, the second roller may be translatable along the first transverse axis between a plurality of stable positions.

By “stable positions” it is meant positions in which the first roller and the second roller can operate, rotating as the conveyor belt advances, without translating transversely uncontrollably.

The present invention may have, in one or more of its aspects, at least one of the preferred features described below. Such features may be present individually or in combination with each other, unless expressly stated otherwise, both in the apparatus and in the method of the present invention.

Preferably, the first roller and/or the second roller are independently translatable with respect to each other.

Preferably, the first roller and/or the second roller are translatable respectively along the first transverse axis and the second transverse axis independently of each other.

Preferably, a motorized drive shaft is provided.

Preferably, said drive shaft comprises a plurality of teeth.

Preferably, said at least one conveyor belt is wound around said drive shaft.

Preferably, said at least one conveyor belt is wound around said first roller, second roller and drive shaft.

Preferably, said at least one conveyor belt comprises a plurality of engagement portions extended along the closed path.

Preferably, said plurality of engagement portions comprises three engagement portions.

Preferably, said engagement portions extend along the closed path parallel to each other.

Preferably, said engagement portions are transversely spaced from each other. Preferably, said at least one engagement portion comprises a row of teeth meshed with respective teeth of said drive shaft.

Preferably, each an engagement portion comprises a row of teeth meshed with respective teeth of said drive shaft.

Preferably, said row of teeth extends along said closed path.

Preferably, said drive shaft is configured to drive said conveyor belt along the closed path to move said transport surface between the receiving position and the feeding position.

Preferably, said at least one engagement portion comprises a thickening band continuous along said closed path.

Preferably, each engagement portion comprises a thickening band continuous along said closed path.

Preferably, the teeth of said at least one engagement portion protrude from said thickening band.

Preferably, said motorized drive shaft is rotatable about a transverse drive axis parallel to, and spaced from, said first transverse axis and second transverse axis.

Preferably, the teeth of said at least one engagement portion are configured to slide transversely with respect to the teeth of said drive shaft without losing the mutual meshing.

Preferably, the teeth of each engagement portion are configured to slide transversely with respect to the teeth of said drive shaft without losing the mutual meshing.

Preferably, the teeth of said drive shaft have an extension measured in the transverse direction that is greater than a width measured in the transverse direction of said at least one engagement portion and preferably greater than a width measured in the transverse direction of said conveyor belt.

Preferably, each tooth of said drive shaft is configured to engage all the rows of teeth of said engagement portions.

Preferably, said at least one engagement portion protrudes from said conveyor belt with a trapezoidal profile in a section perpendicular to a direction of movement of the conveyor belt.

Preferably, said at least one guide portion of the first roller is formed by an annular recess.

Preferably, said annular recess of the guide portion of the first roller extends circumferentially around the first transverse axis.

Preferably, said annular recess of the guide portion of the first roller has a trapezoidal profile in a section through the first transverse axis.

Preferably, said at least one guide portion of the second roller is formed by an annular recess.

Preferably, said annular recess of the guide portion of the second roller extends circumferentially around the second transverse axis.

Preferably, said at least one engagement portion engages said annular recess of said at least one guide portion of the first roller and/or of the second roller.

Preferably, said at least one engagement portion is counter-shaped to said annular recess of said at least one guide portion of the first roller and/or of the second roller.

Preferably, the teeth of said at least one engagement portion engage said annular recess of the guide portion of the first roller and/or of the guide portion of the second roller.

Preferably, said thickening band engages said annular recess of the guide portion of the first roller and/or of the guide portion of the second roller.

Preferably, said conveyor belt extends transversely between opposite side edges.

Preferably, said conveyor belt comprises two side engagement portions.

Preferably, each side engagement portion extends along a respective side edge. Preferably, said conveyor belt comprises a central engagement portion.

Preferably, said central engagement portion extends along a centreline of said conveyor belt.

Preferably, each engagement portion is engaged in a respective guide portion of the first roller and/or of the second roller.

Preferably, there at least one plate defining a longitudinal sliding plane for said transport surface is provided.

Preferably, said at least one plate comprises a longitudinal suction channel, open on said sliding plane and fluidly couplable to a suction system.

Preferably, said conveyor belt comprises a plurality of through suction holes, configured to exert a suction action such as to retain said piece against said transport surface.

Preferably, said suction channel has a width in the transverse direction such that the suction holes of the transport surface are in fluid communication with said suction channel regardless of the position of said first roller along the first transverse axis and/or of said second roller along the second transverse axis.

Preferably, said suction holes are configured to overlap said suction channel between said first roller and said second roller.

Preferably, said suction holes are configured to overlap a centreline of said suction channel between said first roller and said second roller.

Preferably, said suction channel has a transverse dimension greater than the diameter of said suction holes.

Preferably, said suction channel has a transverse dimension greater than twice the diameter of said suction holes.

Preferably, said suction channel has a transverse dimension three times the diameter of said suction holes.

Preferably, said suction channel has a transverse dimension comprised between 3 mm and 9 mm, more preferably between 4 mm and 8 mm, even more preferably between 5 mm and 7 mm, for example 6 mm. Preferably, each suction hole has a diameter comprised between 0.5 mm and 4 mm, more preferably between 1 mm and 3 mm, even more preferably between 1 .5 mm and 2.5 mm, for example 2 mm.

Preferably, said suction channel has a longitudinal extension equal to at least half of the distance between the receiving position and the feeding position. Preferably, said suction channel has a longitudinal extension equal to at least 80% of the distance between the receiving position and the feeding position.

Preferably, a first pin is provided.

Preferably, said first pin extends along said first transverse axis.

Preferably, said first pin is locked in rotation with respect to said first transverse axis.

Preferably, said first pin is translatable in a controlled manner along said first transverse axis.

Preferably, said first roller is rotatably mounted, idle, on said first pin about said first transverse axis.

Preferably, a second pin is provided.

Preferably, said second pin extends along said second transverse axis.

Preferably, said second pin is locked in rotation with respect to said second transverse axis.

Preferably, said second pin is translatable in a controlled manner along said second transverse axis.

Preferably, said second roller is rotatably mounted, idle, on said second pin about said second transverse axis.

Preferably, a first actuator is provided.

Preferably, the first actuator is of the rotating type.

Preferably, the first actuator is configured to controllably translate the first pin along the first transverse axis.

Preferably, the first actuator is configured to controllably lock the first pin in stable positions along the first transverse axis.

Preferably, the first actuator is coupled to said first pin by means of a screw-nut mechanism, preferably with recirculating balls.

Preferably, a second actuator is provided.

Preferably, the second actuator is of the rotating type.

Preferably, the second actuator is configured to controllably translate the second pin along the first transverse axis.

Preferably, the second actuator is configured to controllably lock the second pin in stable positions along the second transverse axis.

Preferably, the second actuator is coupled to said second pin by means of a screw-nut mechanism, preferably with recirculating balls.

Preferably, the first actuator and/or the second actuator are independently actuatable with respect to each other.

Preferably, determining a first translation value of the first roller is provided.

Preferably, determining a second translation value of the second roller is provided.

Preferably, the first translation value of the first roller and the second translation value of the second roller are determined such that, if the piece is received at the receiving position with a receiving orientation other than a preset feeding orientation, the first value and the second value are different each other and the difference between the first value and the second value is such that the piece is rotated from the receiving orientation to the preset feeding orientation.

Preferably, determining a first translation value of the first roller and a second translation value of the second roller is provided such that, if the receiving position is transversely offset from the preset feeding position, the first value and the second value are determined so as to transversely translate the piece from the receiving position a position coincident with, or transversely aligned with, the preset feeding position.

Preferably, transporting a piece of sheet material from the receiving station to the feeding station comprises longitudinally translating the transport surface and stopping the transport surface when the piece of material arrives at the preset feeding position.

Preferably, translating the transport surface longitudinally and stopping the transport surface when the piece of material arrives at the preset feeding position comprises determining the longitudinal translation distance of the transport surface as a function of a longitudinal position in which said piece is received in the receiving position.

Further characteristics and advantages of the present invention will become clearer from the following detailed description of a preferred embodiment thereof, with reference to the appended drawings and provided by way of indicative and non-limiting example, in which: figure 1 shows a perspective view of an apparatus for feeding pieces of a sheet material according to the present invention; figure 2 shows a top view of the apparatus of figure 1 ; figure 3 shows a side view of the apparatus of figure 1 , with some components removed to highlight others; figure 4 shows a detail of the apparatus of figure 1 ; figure 5 shows a detail of the apparatus of figure 1 ; figure 6 shows a schematic sectional view of a detail of the apparatus of figure 1 ; figure 7 shows a sectional view of the apparatus of figure 1 , with some components removed to highlight others; figures 8A and 8B show respective sectional views of some components of the apparatus of figure 1 ; figure 9 shows a perspective view of some components of the apparatus of figure 1 .

The representations in the appended figures do not necessarily have to be understood in scale and do not necessarily respect the proportions between the various parts. An apparatus for feeding pieces of a sheet material is indicated in the attached figures with number 1.

The apparatus 1 comprises a main frame 10, preferably fixed, on which the components described below are mounted. The main frame 10 extends longitudinally. In the illustrated embodiment, the main frame 10 is configured as a box-like body.

The apparatus 1 further comprises a secondary frame 11 , transversely spaced from the main frame 11. In the illustrated embodiment, the secondary frame 11 comprises a plate.

The apparatus 1 comprises a conveying actuator 15, preferably a rotating electric motor. The conveying actuator 15 is mounted on the main frame 10, preferably on the opposite side with respect to the secondary frame 11 . The conveying actuator 15 comprises a rotor shaft (not illustrated) protruding towards a through opening defined in the main frame 10.

The apparatus 1 comprises a drive shaft 16 rotatably drivable by the conveying actuator 15, illustrated in figures 5 and 9. In the illustrated embodiment, the drive shaft 16 is rotatably mounted to the main frame 10 by means of a bearing 17. The drive shaft 16 is further rotatably mounted to the secondary frame 11 by means of a bearing 18.

The drive shaft 16 extends transversely from the main frame 10 to the secondary frame 11. The drive shaft 16 is mounted integral with the rotor shaft of the conveying actuator 15. The drive shaft 16 is also locked in translation with respect to the main frame 10.

The drive shaft 16 is rotatable about a transverse drive axis T. The drive shaft 16 is toothed. The drive shaft 16 comprises a plurality of teeth 19 that extend transversely, preferably over a length greater than half the length of the drive shaft 16, even more preferably over a length greater than three-quarters the length of the drive shaft 16.

The apparatus 1 comprises a first actuator 20, preferably a rotating electric motor. The first actuator 20 is fixedly mounted on the main frame 10, preferably on the opposite side with respect to the secondary frame 11 .

The first actuator 20 comprises a rotor shaft 21 protruding towards a through opening defined in the main frame 10.

A first pin 26 is illustrated in figures 7 and 8A. The first pin 26 extends transversely from a first end 26a to a second end 26b. The first pin 26 is slidable in the transverse direction along a respective first transverse axis T 1 . The first pin 26 is slidably mounted to the main frame 10 at the first end 26a. The first pin 26 is further slidably mounted to the secondary frame 11 at the second end 26b.

The first pin 26 is drivable to slide from the first actuator 20 by means of a screw- nut screw mechanism 27, preferably of the recirculating type of balls. The screw- nut screw mechanism 27 comprises a sliding portion 28 located at the first end 26a of the first pin 26, integral with the first pin 26, and slidable along the first transverse axis T1. The screw-nut screw mechanism 27 further comprises a rotating portion 29, rotatable with respect to the first transverse axis T1 and mounted in engagement with the sliding portion 28. The rotating portion 29 is integral in rotation with the rotor shaft 21 of the first actuator 20, also rotatable about the first transverse axis T1 .

In the illustrated embodiment the sliding portion 28 comprises an internally threaded hole and the rotating portion 29 comprises an externally threaded stem and engaged in the hole of the sliding portion 28. A plurality of balls (not illustrated) is interposed between the sliding portion 28 and the rotating portion 29 to reduce friction.

The first pin 26 is locked in rotation with respect to the first transverse axis T1 . In the illustrated embodiment, the sliding portion 28 is constrained to slide along the first transverse axis T1 within a fixed bushing 30. The bushing 30 is integral with the main frame 10. The sliding portion 28 comprises a straight guide 31 , parallel to the first transverse axis T1 . An insert 32 is fixedly mounted on the bushing 30, protruding towards the first transverse axis T1 , to engage the guide 31 and lock it in rotation, constraining it to slide transversely.

The bushing 30 is further configured to stop the translation of the first pin 26 in a preset end-of-travel position. In particular, the bushing 30 comprises an end-of- travel wall 33 and the sliding portion 28 comprises a shoulder 34 configured to abut against the end-of-travel wall 33 when the first pin 26 reaches the preset end-of-travel position.

A first roller 35 is illustrated in figures 7 and 8A. The first roller is mounted idle on the first pin 26. The first roller 35 is rotatable with respect to the first pin 26 about the first transverse axis T1. The first roller 35 is mounted integral in translation with the first pin 26 along the first transverse axis T1 .

The first roller 35 comprises at least one guide portion 36. Preferably, the first roller 35 comprises a plurality of guide portions 36. In the illustrated embodiment, the first roller 35 comprises six guide portions 36.

Each guide portion 36 is defined by an annular recess obtained on the outside of the first roller 35 around the first transverse axis T1. The annular recess has a trapezoidal profile in a section passing through the first transverse axis. Respective annular shoulders that transversely delimit each recess of each guide portion 36 are defined on the first roller 35. Each guide portion 36 is symmetrical in rotation about the first transverse axis T1 .

The apparatus 1 comprises a second actuator 40 analogous to the first actuator 20, preferably a rotating electric motor. The second actuator 40 is fixedly mounted on the main frame 10, preferably on the opposite side with respect to the secondary frame 11 . The second actuator 40 is independently actuatable with respect to the first actuator 20.

The second actuator 40 comprises a rotor shaft 41 protruding towards a through opening defined in the main frame 10.

A second pin 46, analogous to the first pin 26 is illustrated in figures 7 and 8B. The second pin 46 extends transversely from a first end 46a to a second end 46b. The second pin 46 is slidable in the transverse direction along a respective second transverse axis T2. The second pin 46 is slidably mounted on the main frame 10 at the first end 46a. The second pin 46 is further slidably mounted to the secondary frame 11 at the second end 46b.

The second pin 46 is drivable to slide from the second actuator 40 by means of a screw-nut screw mechanism 47, preferably of the recirculating type of balls. The screw-nut screw mechanism 47 comprises a sliding portion 48 located at the first end 46a of the second pin 46, integral with the second pin 46, and slidable along the second transverse axis T2. The screw-nut screw mechanism 47 further comprises a rotating portion 49, rotatable with respect to the second transverse axis T2 and mounted in engagement with the sliding portion 48. The rotating portion 49 is integral in rotation with the rotor shaft 41 of the second actuator 40, also rotatable about the second transverse axis T1 . In the illustrated embodiment the sliding portion 48 comprises an internally threaded hole and the rotating portion 49 comprises an externally threaded stem and engaged in the hole of the sliding portion 48. A plurality of balls (not illustrated) is interposed between the sliding portion 48 and the rotating portion 49 to reduce friction.

The second pin 46 is locked in rotation with respect to the second transverse axis T2. In the illustrated embodiment, the sliding portion 48 is slidably constrained along the second transverse axis T2 within a bushing 50. The bushing 50 is integral with the main frame 10. The sliding portion 48 comprises a straight guide 51 , parallel to the first transverse axis T2. An insert 52 is fixedly mounted on the bushing 50, protruding towards the second transverse axis T2, to engage the guide 51 and lock it in rotation, constraining it to slide transversely.

The bushing 50 is further configured to stop the translation of the second pin 46 at a preset end-of-travel position. In particular, the bushing 50 comprises an end- of-travel wall 53 and the sliding portion 48 comprises a shoulder 54 configured to abut against the end-of-travel wall 53 when the second pin 46 reaches the preset end-of-travel position.

A second roller 55, analogous to the first roller 35, is illustrated in figures 7 and 8B. The second roller 55 is mounted idle on the second pin 46. The second roller 55 is rotatable with respect to the second pin 46 about the second transverse axis T2. The second roller 55 is mounted integral in translation with the second pin 46 along the first transverse axis T2.

The second roller 55 comprises at least one guide portion 56. Preferably, the second roller 55 comprises a plurality of guide portions 56. In the illustrated embodiment, the second roller 55 comprises six guide portions 56.

Each guide portion 56 is defined by an annular recess obtained on the outside of the second roller 55 around the second transverse axis T2. Respective annular shoulders that transversely delimit each recess of each guide portion 56 are defined on the second roller 55. Each guide portion 56 is symmetrical in rotation about the second transverse axis T2.

The apparatus 1 comprises at least one conveyor belt 60. In the illustrated embodiment, the apparatus 1 comprises two conveyor belts 60 arranged side by side one another. Each conveyor belt 60 extends along a closed path. Each conveyor belt 60 extends transversely between opposite side edges 60a, which delimit it transversely.

Each conveyor belt 60 is wound on the first roller 35, the second roller 55, and the drive shaft 16. In the illustrated embodiment, the closed path of the conveyor belt 60 is substantially triangular and the vertices are defined by the first roller 35, the second roller 55 and the drive shaft 16.

Each conveyor belt 60 comprises at least one engagement portion 61 protruding and extended along the closed path of the conveyor belt 60.

Preferably, each conveyor belt 60 comprises a plurality of engagement portions 61 parallel to each other and transversely spaced from each other. In the illustrated embodiment, each conveyor belt 60 comprises three engagement portions 61 .

Two of the engagement portions 61 are arranged at respective side edges 60a of the conveyor belt 60. A further engagement portion 61 is arranged at a centreline axis of the conveyor belt 60.

Each engagement portion 61 has a trapezoidal profile in all sections orthogonal to the direction of movement of the conveyor belt 60 along the closed path.

Each engagement portion 61 is configured to engage a respective guide portion 26 of the first roller 35 and a respective guide portion 56 of the second roller 55. The profile of the engagement portion 61 is counter-shaped to the profile of the annular recess of the respective guide portions 36, 56.

Each engagement portion 61 comprises a thickening band 61a continuous along the closed path. The thickening band 61 a protrudes from the conveyor belt 60 on the side opposite to the transport surface 63.

Each engagement portion 61 further comprises a row of teeth 62 placed in succession along the closed path of the conveyor belt 60. The teeth 62 protrude from the thickening band 61 a on the side opposite to the transport surface 63. The teeth 62 are oriented transversely. The teeth 62 have tapered side edges to define the trapezoidal profile of the engagement portion 61 .

The teeth 62 of each engagement portion 61 are meshed on the drive shaft 16, such that a rotation of the drive shaft 16 drives the conveyor belt 60 along the closed path.

The total number of engagement portions 61 of the conveyor belts 60 corresponds to the number of guide portions 36 of the first roller 35 and the number of guide portions 56 of the second roller 55.

Each conveyor belt 60 is configured to slide transversely on the drive shaft 16 without the respective teeth 62 losing meshing with the drive shaft 16. The teeth 62 of each engagement portion 61 have a transverse extension lower than the transverse extension of the teeth 19 of the drive shaft 16 and can slide transversely thereon while maintaining mutual engagement. In particular, the transverse extension of the teeth 62 of each engagement portion 61 is at least ten times less than the transverse extension of the teeth 19 of the drive shaft 16.

On each conveyor belt 60 a transport surface 63 is defined on which a piece of sheet material, preferably an electrode precursor in sheet form, is transportable. Each transport surface 63 extends longitudinally from a first end 64 to a second end 65. The first end 64 is defined at the first roller 35. The second end 65 is defined at the second roller 55.

Each transport surface 63 is configured to receive a piece of sheet material at a receiving position 63a and to transport it as far as a feeding position 63b longitudinally spaced from the receiving position 63a. In the illustrated embodiment, the receiving position 63a is located at the first end 64 and the feeding position 63b is located at the second end 65.

The piece of material is transported by driving the conveyor belt 60 along the closed path by means of the conveying actuator 15.

Each conveyor belt 60 comprises a plurality of through suction holes 66. The suction holes 66 are circular. The suction holes 66 are distributed longitudinally along the closed path of the conveyor belt 60 along at least one row of suction holes 66. In the illustrated embodiment, two rows of parallel suction holes 66 are provided for each conveyor belt 60.

At least one plate 70 is provided for each conveyor belt 60, illustrated in figure 6. The plate 70 is mounted integral with the main frame 10. In the illustrated embodiment, two plates 70 are provided for each conveyor belt 60.

Each plate 70 defines a sliding plane 71 on which the conveyor belt 60 rests between the first roller 35 and the second roller 55. The sliding plane 71 extends in the longitudinal and transverse directions. The conveyor belt 60 slides on the sliding plane 71 when the transport surface 63 advances longitudinally between the receiving position 63a and the feeding position 63b.

Each plate 70 comprises a suction channel 72 extended longitudinally between the receiving position 63a and the feeding position 63b. The suction holes 66 of each row are superimposed on a respective suction channel 72 between the receiving position 63a and the feeding position 63b, so as to slide longitudinally along the suction channel 72.

The width, measured in the transverse direction, of the suction channel 72 is greater than the diameter of the suction holes 66.

A suction system (not illustrated) is configured to exert a suction action towards the transport surface 63 through the suction channel 72 of each plate 70 and the suction holes 66. The suction system is configured to make the sheet to be transported adhere to the transport surface 63.

The conveyor belt 60 is wound on the first roller 35 so as to draw the first roller 35 in rotation about the first transverse axis T1 when the conveyor belt 60 is driven along its closed path.

The conveyor belt 60 is wound on the first roller 35 so as to follow it in translation along the first transverse axis T1. Each engagement portion 61 engages a respective guide portion 36 of the first roller 35. In particular, each row of teeth 62 engages the groove of the guide portion 36. Preferably, there is no transverse play between the engagement portion 61 and the respective guide portion 36. When the first roller 35 translates transversely, the guide portion 36 transversely drags the engagement portion 61 of the conveyor belt 60 and the conveyor belt 60 translates locally together with the first roller 35.

A transverse translation of the first end 64 of each transport surface 63 along the first transverse axis T1 is actuatable by means of the first actuator 20. The first actuator 20 is configured to translate the first pin 26 by means of the screw-nut screw mechanism 27. The first roller 35 is configured to translate together with the first pin 26. The translation of the first roller 35 results in a corresponding local translation of the conveyor belt 60 at the first end 64 of the transport surface 63 by coupling each engagement portion 61 with the respective guide portion 36. The first end 64 of the transport surface 63 is translatable along the first transverse axis T1 in a first sliding direction by actuating the first actuator 20 in a first rotating direction. The first end 64 of the transport surface 63 is further translatable along the first transverse axis T1 in a second sliding direction opposite to the first sliding direction by actuating the first actuator 20 in a second rotating direction opposite to the first rotating direction.

The conveyor belt 60 is wound on the second roller 55 so as to draw the second roller 55 in rotation about the second transverse axis T2 when the conveyor belt 60 is driven along its closed path.

The conveyor belt 60 is wound on the second roller 55 so as to follow it in translation along the second transverse axis T2. Each engagement portion 61 engages a respective guide portion 56. In particular, each row of teeth 62 engages the groove of the guide portion 56. Preferably, there is no transverse play between the engagement portion 61 and the respective guide portion 56. When the second roller 55 translates transversely, the guide portion 56 transversely drags the engagement portion 61 of the conveyor belt 60 and the conveyor belt 60 translates locally together with the second roller 55.

A transverse translation of the second end 65 of each transport surface 63 along the second transverse axis T2 is actuatable by means of the second actuator 40. The second actuator 40 is configured to translate the second pin 46 by means of the screw-nut screw mechanism 47. The second roller 55 is configured to translate together with the second pin 46. The translation of the second roller 55 results in a corresponding local translation of the conveyor belt 60 at the second end 65 of the transport surface 63 by coupling each engagement portion 61 with the respective guide portion 56.

The second end 65 of the transport surface 63 is translatable along the second transverse axis T2 in a first sliding direction by actuating the first actuator 40 in a first rotating direction. The second end 65 of the transport surface 63 is further translatable along the second transverse axis T2 in a second sliding direction opposite to the first sliding direction by actuating the second actuator 40 in a second rotating direction opposite to the first rotating direction.

By translating the first end 64 and the second end 65 of the transport surface 63 in a pre-established way respectively along the first transverse axis T1 and the second transverse axis T2 it is possible to cause controlled transverse translations of the transport surface 63 and controlled rotations of the transport surface 63 about an axis perpendicular to the transport surface 63. During such translations and rotations, the suction holes 66 translate transversely on the suction channel 72. The suction channel 72 has a width such that the suction holes 66 remain superimposed on the suction channel 72 in all allowed positions of the first roller 35 along the first transverse axis T1 and of the second roller 55 along the second transverse axis T2.

Claims

1. Apparatus (1 ) for feeding pieces of a sheet material, comprising: a first roller (35) rotatable about a first transverse axis (T1 ); a second roller (55) rotatable about a second transverse axis (T2) parallel to, and spaced longitudinally from, said first transverse axis (T1 ); at least one conveyor belt (60) wound along a closed path around said first roller (35) and second roller (55), said conveyor belt (60) defining a transport surface (63) extended longitudinally from a first end (64) located at said first roller (35) to a second end (65) located at said second roller (55) and configured to transport a piece of sheet material from a receiving position (63a) to a feeding position (63b) spaced longitudinally from said receiving position (63a) towards said second end (65); wherein said conveyor belt (60) comprises at least one engagement portion (61 ) extended along the closed path, and wherein: said first roller (35) is translatable, independently with respect to said second roller, along said first transverse axis (T1 ) between a plurality of stable positions and comprises at least one guide portion (36) extended around said first transverse axis (T1 ) and arranged in engagement with said engagement portion (61 ) so that a transverse translation of said first roller (35) results in a corresponding transverse translation of the first end (64) of the transport surface (63); and/or said second roller (55) is translatable, independently with respect to said first roller, along said second transverse axis (T2) between a plurality of stable positions and comprises at least one guide portion (56) extended around said second transverse axis (T2) and arranged in engagement with said engagement portion (61 ) so that a transverse translation of said second roller (55) results in a corresponding transverse translation of the second end (65) of the transport surface (63).

2. Apparatus (1 ) according to claim 1 , comprising a motorised drive shaft (16), said at least one conveyor belt (60) being wound around said drive shaft (16); wherein: said at least one engagement portion (61 ) comprises a row of teeth (62) meshed with respective teeth (19) of said drive shaft (16), said drive shaft (16) is configured to drive said conveyor belt (60) along the closed path to move said transport surface (63) between the receiving position (63a) and the feeding position (63b).

3. Apparatus (1 ) according to claim 2, said at least one engagement portion (61 ) comprising a thickening band (61 a) continuous along said closed path, the teeth (62) of said at least one engagement portion (61 ) protruding from said thickening band (61 a).

4. Apparatus (1 ) according to claim 2 or 3, wherein said motorised drive shaft (16) is rotatable about a transverse drive axis (T) parallel to, and spaced from, said first transverse axis (T1 ) and second transverse axis (T2); wherein the teeth (62) of said at least one engagement portion (61 ) are configured to slide transversely with respect to the teeth (19) of said drive shaft (16) without losing the mutual meshing.

5. Apparatus (1 ) according to any one of claims 2 to 4, wherein the teeth of said drive shaft (16) have an extension measured in the transverse direction that is greater than a width measured in the transverse direction of said at least one engagement portion (61 ) and preferably greater than a width measured in the transverse direction of said conveyor belt (60).

6. Apparatus (1 ) according to any one of the preceding claims, wherein said at least one engagement portion (61 ) protrudes from said conveyor belt (60) with a trapezoidal profile in a section perpendicular to a direction of movement of the conveyor belt (60), and wherein said at least one guide portion (36) of the first roller (35) is formed by an annular recess having a trapezoidal profile in a section passing through the first transverse axis (T 1 ) and/or said at least one guide portion (56) of the second roller (55) is formed by an annular recess having a trapezoidal profile in a section passing through the second transverse axis (T2).

7. Apparatus (1 ) according to any one of the preceding claims, wherein said conveyor belt (60) extends transversely between opposite side edges (60a), said conveyor belt (60) comprising two side engagement portions (61 ), each extended along a respective side edge (60a).

8. Apparatus (1 ) according to any one of the preceding claims, wherein said conveyor belt (60) comprises a central engagement portion (61 ) extended along a centreline of said conveyor belt (60).

9. Apparatus (1 ) according to any one of the preceding claims, comprising at least one plate (70) defining a longitudinal sliding plane (71 ) for said transport surface (63), wherein: said at least one plate (70) comprises a longitudinal suction channel, open on said sliding plane (71 ) and fluidly couplable to a suction system; said conveyor belt (60) comprises a plurality of through suction holes (66), configured to exert a suction action such as to retain said piece against said transport surface (63); wherein said suction channel (72) has a width in the transverse direction such that the suction holes (66) of the transport surface (63) are in fluid communication with said suction channel (72) regardless of the position of said first roller (35) along the first transverse axis (T1 ) and/or of said second roller (55) along the second transverse axis (T2).

10. Apparatus (1 ) according to any one of the preceding claims, comprising: a first pin (26) on which said first roller (35) is rotatably mounted, idle, about said first transverse axis; and a second pin (46) on which said second roller (55) is rotatably mounted, idle, about said second transverse axis; wherein said first pin (26) is translatable in a controlled manner along said first transverse axis and said first roller (35) is integral in translation with said first pin (26); and/or said second pin (46) is translatable in a controlled manner along said second transverse axis and said second roller (55) is integral in translation with said second pin (46).

11. Apparatus (1 ) according to claim 10, comprising: a first rotating actuator (20) coupled to said first pin (26) by means of a screw-nut screw mechanism (27), preferably with recirculating balls, and/or a second rotating actuator (40) coupled to said second pin (46) by means of a screw-nut screw mechanism (47), preferably with recirculating balls.

12. Apparatus (1 ) according to any one of the preceding claims, wherein said first roller (35) and said second roller (55) are translatable respectively along the first transverse axis (T 1 ) and the second transverse axis (T2) independently of each other.

13. Method for feeding pieces of a sheet material, comprising: providing an apparatus (1 ) for feeding pieces of a sheet material according to any of the preceding claims; transporting a piece of sheet material from the receiving station (63a) to the feeding station (63b); if the piece in the receiving position (63a) has an orientation other than a preset feeding orientation and/or if the receiving position (63a) is transversely offset from a preset feeding position, translating said first roller (35) along said first transverse axis (T1 ) and/or translating said second roller (55) along said second transverse axis (T2).

14. Method according to claim 13, comprising determining a first translation value of the first roller (35) and a second translation value of the second roller (55) such that: if the piece is received at the receiving position (63a) with a receiving orientation other than a preset feeding orientation, the first value and the second value are different from each other and the difference between the first value and the second value is such that the piece is rotated from the receiving orientation to the preset feeding orientation; if the receiving position (63a) is transversely offset from the preset feeding position, the first value and the second value are determined so as to transversely translate the piece from the receiving position (63a) to a position coinciding with, or transversely aligned to, the preset feeding position.