WO2023203474A1

WO2023203474A1 - Device for laying down leathers and method using the device

Info

Publication number: WO2023203474A1
Application number: PCT/IB2023/053942
Authority: WO
Inventors: Andrea Trevisan; Luca MARCAZZAN
Original assignee: Brevetti C.E.A. S.P.A.
Priority date: 2022-04-19
Filing date: 2023-04-18
Publication date: 2023-10-26
Also published as: IT202200007745A1

Abstract

A device (1) for laying down leathers (16, 17), comprising: a first conveying roller (2); a conveyor belt (4) defining a conveying surface (5) to support a leather (16, 17), wrapped around the first conveying roller (2); first motorization means (6) of the first conveying roller (2) to move the conveying surface (5); second motorization means (7) to move the first conveying roller (2) relative to a rest surface (14) arranged below the device (1); a first guide unit (8) cooperating with the conveyor belt (4) to maintain the leather (16, 17) in contact with a first section (4b) of the belt (4) during movement of the conveying surface (5) towards the first conveying roller (2) to cause a deviation of the leather (16, 17); first operating means (10) to rotate the first guide unit (8) to change the length of the first section (4b) and, in turn, the extent of the deviation of the leather (16, 17). The second motorization means (7) move the first conveying roller (2) independently of the movement of the conveying surface (5) caused by the first motorization means (6), in order to change the point of the rest surface (14) where the lay down of a first leather (16) of said leathers (16, 17) starts.

Description

"DEVICE FOR LAYING DOWN LEATHERS AND METHOD USING THE DEVICE" DESCRIPTION

FIELD OF APPLICATION

The present invention is generally applicable to the technical field of machines for the processing of leathers. In particular, the object of the invention is a device for laying down leathers on a rest surface, particularly suited to stacking leathers on one another.

STATE OF THE ART

Devices exist and are known to lay down leathers exiting a processing plant in such a way as to stack the leathers on one another, to allow them to be transported to subsequent processing steps afterwards.

One of the requirements for the above mentioned lay-down devices is that it arranges each leather on the rest surface, or on the previous leather, without forming folds or wrinkles, that could bring damages to the leather itself, in particular when the leather is pressed by other leathers subsequently stacked on it.

A particular case of the above mentioned folds occurs when the last portion of the leather comes to be folded back during the lay-down operation, which might occur due to the high operating speed required for the above mentioned devices.

Generally, the lay-down devices of known kind comprise a carriage provided with a pair of mutually parallel rollers between which a horizontal conveyor belt is wounded. The carriage is arranged above the rest surface and is moved according to a horizontal direction that is orthogonal to the axes of the rollers. Moreover, the rollers are driven so as move the conveyor belt with respect to the rollers according to the above mentioned direction, and independently of the movement of the carriage.

Firstly, each leather to be laid down is arranged on the conveyor belt. Subsequently, the leather is progressively laid down on the underlying rest surface through a combined movement of the carriage and the conveyor belt.

In particular, if the carriage is moved in a direction that is opposite to the direction according to which the upper section of the belt is moved relative to the rollers, the leather is laid on the rest surface with the same orientation it had on the conveyor belt. A lay-down process of the leather of the kind just mentioned will be indicated hereinafter, for brevity, "direct lay-down mode".

If, on the other hand, the carriage is moved in the same direction as the direction of movement of the upper section of the belt, it is possible to achieve a overturned lay-down mode of the leather. A lay-down process of the kind just mentioned will be indicated hereinafter, for brevity, "overturned lay-down mode".

The lay-down devices of known kind also comprise a drive unit suited to prevent formation of wrinkles on the leather during lay down and/or unwanted overturning of the last portion of the leather.

According to a known version, the above mentioned drive unit comprises an idle guide roller that faces the carriage roller arranged on the side where the leather gets off on the rest surface. The guide roller is connected to the carriage through a structure adapted to swing around the axis of the carriage roller between a rest position, where the guide roller is arranged above the carriage roller, and an operating position, in which the guide roller is aligned to the carriager roller according to a substantially horizontal plane. When the guide roller is arranged in the above mentioned operating position, it is in contact with the portion of the leather that has been already laid down during the movement of the carriage. As a consequence, the guide roller limits possible formation of wrinkles on the leather itself, and, moreover, it guides the last portion of the leather thus preventing its overturning.

The drive unit of the known kind just mentioned has the drawback that it is uncapable of guiding the leather while it leaves the conveyor belt, because the guide roller is always separated from the conveyor belt, hence it cannot affect the descent trajectory of the leather.

A further drawback of the above mentioned known drive unit is that it is unsuited to guide the leather in the overturned lay-down mode.

In an attempt to overcome the above mentioned drawbacks, it is known to use a drive unit of a different kind, comprising two of the above mentioned guide rollers, a guide belt wounded between the two guide rollers being kept in contact with the conveyor belt of the carriage at the level of the corresponding roller, in such a way as to keep the leather in contact with the conveyor belt on a predefined portion of the curved surface defined by the corresponding roller. During laying down of the leather, the two rollers maintain the same position relative to the carriage.

Although the known drive unit according to the second kind just mentioned allows to achieve a more precise guiding of the leather while the leather leaves the conveyor belt, it has the drawback that it is not adapted to all the phases of the lay- down of the leather, because of the steadiness of the guide belt configuration relative to the conveyor belt during the entire lay-down process.

The above mentioned steady configuration brings a further drawback that it is not possible to adapt the guiding mode to the type and dimension of the leather, wherein the above type and dimension influence the behavior of the leather, and, in particular, the chance that the last section of the leather is overturned.

A further drawback implied by the above mentioned steady configuration is the impossibility to achieve an optimal guide in both direct and overturned lay-down modes.

All the drawbacks of the known art above described bring a further drawback of limiting the maximum speed at which leathers can be laid down without excessive formation of folds and wrinkles occurring.

A lay-down device of known kind is illustrated in document AU 3750671 A.

SUMMARY OF THE INVENTION

The present invention aims at overcoming the above mentioned drawbacks of the known art at least in part.

In particular, it is an aim of the invention to provide a lay-down device allowing to laying down a leather on a rest surface more rapidly compared to the known devices above mentioned, keeping the same amount of folds and wrinkles on the leathers.

More particularly, it is an aim of the invention that the above mentioned lay- down device allows to adapt the leather guiding according to the different phases in the lay-down process, the kind and dimention of the leather, and the lay-down mode, i.e. direct or overturned.

It is a further aim of the invention that the above mentioned lay-down device allows to guide the leather in a better way compared to the lay-down devices of known kind, given the same operating conditions.

The above mentioned aims are reached by a device for laying down leathers, according to the main claim.

The above mentioned aims are reached as well by a method for laying down leathers, according to claim 13.

Further detail features of the invention are specified in the thereof dependent claims.

Advantageously, the higher lay-down speed that can be achieved through the invention allows to increase productivity of the plant embedding the lay-down device.

Still advantageously, the possibility to guide the leathers in a different way according to the operating conditions increases the versatility of the device of the invention, thus allowing to increase the lay-down effectiveness in all operating conditions. The above mentioned aims and advantages, together with others that will be mentioned hereinafter, will be more apparent in the following disclosure of some preferred embodiments of the invention, that is given by way of indicative and nonlimiting examples with the aid of the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 represents the device of the invention for laying down leathers, in axonometric view.

Fig. 2 represents an enlarged detail of Fig. 1, indicated with A.

Fig. 3 represents the detail of Fig. 2, in cross-section lateral view.

Figs, from 4 to 7 represent the lay-down device of Fig. 1, in schematical view and in different operating configurations, corresponding to some steps of the method of the invention.

Fig. 8 represents an elnarged detail of Fig. 6, indicated with B.

Fig. 9 represents an enlarged detail of Fig. 7, indicated with C.

Figs. 10 and 11 represent the lay-down device of Fig. 1, in schematical view and in different operating configurations, corresponding to further steps of the method of the invention.

DETAILED DESCRIPTION OF SOME PREFERRED EMBODIMENTS

The device of the invention for laying down leathers, indicated in Fig. 1 in overall with numeral 1, is particularly suited to be used downstream of a machine or a plant for processing leathers in order to stack the leathers that exit from the above mentioned machine or plant on one another on one or more underlying rest surfaces 14 and 15, that are preferably horizontal. The rest surfaces 14, 15 may belong to corresponding pallets or other removable devices, that may be easily picked up to move the leather stack towards subsequent processing steps.

The above mentioned lay-down device 1 comprises a first conveying roller 2, better seen in Fig. 3, rotatably mounted around a first rotation axis XI integral with a support structure 25.

Further provided is a conveyor belt 4 that defines a conveying surface 5 facing upwards to support a leather indicated in Figs. 4 to 9 with the numeral 16.

A first portion 4a of the belt 4 is wounded around the first conveying roller 2 and follows its curvature, in such a way as to receive its motion. In particular, the first conveying roller 2 is put into rotation around the first rotation axis XI by first motorization means 6, schematically represented in Figs. 1 and 2, in such a way as to move the above mentioned conveying surface 5 and, as a consequence, the leather 16, according to a conveying direction Z orthogonal to the first rotation axis XI. In other words, the first motorization means 6 allow to move the leather 16 relative to the first conveying roller 2.

In particular, the first motorization means 6 can operate the first conveying roller 2 in such a way that the front edge of the leather 16 is being delivered at the roller 2 until descending on the underlying rest surface 14, as it will be better disclosed later.

Preferably but not necessarily the conveying surface 5 is horizontal, bringing evident advantages in terms of operation of the device as it will clearly appear later. However, variant embodiments of the invention, not shown in the drawings, may envisage that the conveying surface 5 be slightly sloped in such a way that its distance from the rest surface 14 progressively decreases towards the first conveying roller 2.

The lay-down device 1 also comprises second motorization means 7, schematically shown in Fig. 1, to move the support structure 25 and, as a consequence, the first conveying roller 2, integrally with the conveyor belt 4 according to a movement direction W that is orthogonal to the first rotation axis XI. During the movement just disclosed, the conveyor belt 4 is kept consantly stretched and in contact with the first conveying roller 4.

It is understood that the second motorization means 7 allow to move the first conveying roller 2 relative to the rest surface 14 in a way that is independent of the movement communicated by the first motorization means 6 to the conveying surface 5 relative to the roller 2 itself, in such a way as to change the position where the leather 16 is laid down on the rest surface 14.

It is clear that, the provision of the mutually indipendent first motorization means 6 and second motorization means 7 allows both to change the point of the rest surface 14 where the lay-down of the leather 16 is started, through a suitable positioning of the first conveying roller 2 relative to the rest surface 14, and to lay down the leather 16 on the said surface through a combined operation of the two motorization means 6 and 7, as it will be better explained later. As a consequence, it is possibile to lay down the leather 16 in such a way as to prevent the formation of wrinkles in the latter.

The lay-down device 1 further comprises a first guide unit 8, cooperating with the conveyor belt 4 in such a way as to maintain the leather in contact with a first section 4b of the above mentioned first belt portion 4a during the movement of the conveyor belt 4, hence of the conveying surface 5, towards the first conveying roller 2 according to the conveying direction Z. That can be seen, for example, in Fig. 8, where the first section 4b is indicated in terms of its angular span. The first guide unit 8 forces the leather 16 to follow the downward curvature of the first conveying roller 2 along the lenght of the above mentioned first section 4b, thus causing a corresponding deviation of the leather 16 with respect to the conveying direction Z towards the underlying rest surface 14 before the leather leaves the first curved portion 4a of the belt 4. Therefore, the first guide unit 8 further facilitates achieving a lay-down of the leather 16 without wrinkles, and, further, avoids that the final edge of the leather be overturned and overlaps the rest of the leather.

The first guide unit 8 is connected to the support structure 25 so that it moves integrally together with the first conveying roller 2, in order to keep its distance from the latter at a constant value.

The lay-down device 1 further comprises first operating means 10 to cause the first guide unit 8 to rotate around a first driving axis Y1 parallel to the first rotation axis XI in such a way as to change the length of the above mentioned first section 4b and, consequently, the extent of the above mentioned deviation of the leather 16. For example, Fig. 9 shows the first guide unit 8 rotated, relative to the position it occupies in Fig. 8, such as to increase the dimension of the first section 4b.

The above mentioned first operating means 10 are configured to rotate the first guide unit 8 between a first position and a second position that correspond to, respectively, a minimum value and a maximum value of the deviation caused on the leather 16.

It is understood that the first guide unit 8, because it keeps the leather 16 in contact with the curved portion 4a of the conveyor belt 4, allows to guide the leather 16 itself on a predefined trajectory, that can be accurately changed by rotating the first guide unit 8 by means of the first operating means 10, in order to cause a consequent change in the deviation angle of the leather 16.

The possibility to change the deviation angle of the leather 16 allows to guide the leather towards the rest surface 14 in the configuration most suited to all different operating conditions, for example, based on the kind and dimensions of the leather, the lay-down modes - i.e. direct or overturned, but also on the different steps of the lay-down procedure of the leather, hence reaching one of the aims of the invention.

Clearly, the possibility to optimally guide the leather 16 in all different operating conditions also allows to increase the lay-down speed, hence reaching a further aim of the invention.

Preferably, the first driving axis Y1 of the first guide unit 8 coincides with the first rotation axis XI of the first conveying roller 2. Advantageously, the configuration just disclosed allows to keep the distance between the first guide unit 8 and the first conveying roller 2 constant while the angular position of the first guide unit 8 changes, in such a way as to optimally guide the leather 16 irrespective of the position of the first guide unit 8.

Still preferably, the first operating means 10 are configured in such a way that, when the first guide unit 8 is arranged in the above mentioned second position, the above mentioned first section 4b extends until a height that is lower compared to that of the first rotation axis XI. If the conveying surface 5 is horizontal, the configuration just disclosed leads to a greater than 90° angle of the deviation of the leather 16 caused by the first guide unit 8.

Advantageously, the configuration just disclosed allows to guide the leather 16 until a height that is closer to that of the rest surface 14, hence further limiting the overturning of the final edge of the leather.

Moreover, due to the above disclosed deviation, the leather 16 crosses the vertical plane tangent to the first curved portion 4a of the conveyor belt 4 and leaves the conveyor belt 4 in a slighly overturned position, as it is clearly shown in Fig. 9. Advantageously, that facilitates the lay-down of the leather 16 in overturned position, as it will be better disclosed later.

As regards the first guide unit 8, preferably and as seen in Fig. 3, that comprises a first guide roller 11 rotatably mounted around a first driving axis Ila that is parallel to the first rotation axis XI. The first guide unit 8 further comprises a guide belt 13, a first portion 13a of which is wounded around the first guide roller 11. The guide belt 13 is arranged so as to face the first portion 4a of the conveyor belt 4 in such a way as to contact the leather 16 on the side that is opposite to the side in contact with the belt 4, in order to keep the leather in contact with the first section 4b of the conveyor belt 4. As a consequence, the guiding of the leather 16 is achieved by means of the contact of the guide belt 13 with the above mentioned opposite side.

Still preferably, the first guide roller 11 is operatively associated with the first conveying roller 2 in such a way as to move the guide belt 13 at the same speed of the conveyor belt 4. Advantageously, the configuration just disclosed prevents wrinkling on the leather 16, because the leather is being driven on both sides at the same speed, hence preventing possible slipping.

Preferably but not necessarily, the first guide roller 11 is associated to the first conveying roller 2 through toothed elements, for example a pair of mutually coupled gear wheels connected to, respectively, the first conveying roller 2 and the first guide roller 11. Obviously, the gear wheel that is connected to the first conveying roller 2 is coaxial to the driving axis Y1 in such a way as to transfer the motion to the first guide roller 11, whatever the angular position of the first guide unit 8.

Variant embodiments of the invention may envisage flexible toothed elements, such as chains and/or belts, in replacement of, or in combination with, the above mentioned gear wheels.

It is understood that, advantageously, the use of the above mentioned toothed elements ensures that the rotational speed between the first guide roller 11 and the first conveying roller 2 remains constant, regardless of the angular position of the first guide unit 8.

Variant embodiments of the invention may envisage that the first guide roller 11 is being driven by the first conveying roller 2 or the conveyor belt 4 through friction elements that are put into mutual contact at the level, for example, of one or both ends.

Preferably, the first guide unit 8 also comprises a second guide roller 12 rotatably mounted around a second driving axis 12a parallel to the first driving axis Ila and at a distance thereof. The guide belt 13 is wounded around the second guide roller 12 in such a way that an intermediate portion 13b of the belt 13 is defined that is not in contact with any one of the above mentioned first guide roller 11 and second guide roller 12.

Moreover, the first guide roller 11 and the second guide roller 12 are arranged, relative to the first driving axis Yl, in such a way that a first area of the above mentioned guide belt 13 proximal to the conveyor belt 4 belongs to the above mentioned intermediate portion 13b at least when the first guide unit 8 is arranged in a position comprised between the first position and the second position.

The guide belt 13 in the configuration just disclosed further improves the accuracy in guiding the leather 16. In fact, thanks to its deformability, the intermediate portion 13b can adapt to the curvature of the leather 16 in contact with the first curved portion 4a of the conveyor belt 4, hence increasing the extent of the portion of the guide belt 13 in contact with the leather.

Still preferably, and as particularly seen in Figs. 3, 8 and 9, the two guide rollers 11, 12 are arranged in such a way that the previously mentioned first area of the guide belt 13 closer to the first conveying roller 2 is closer to the guide roller 11 arranged downstream of the conveying roller 2, i.e. the lower one, compared to the other guide roller 12 arranged upstream of the conveying roller 2, i.e. the higher one. In other words, the intermediate portion 13b of the guide belt 13 extends upstream of the first conveying roller 2 for a portion whose lenght is bigger compared to the portion extending downstream of the first conveying roller 2.

The configuration just disclosed leads to a better guiding accuracy of the leather 16 at the level of the inlet area of the first guide unit 8, in that it causes the leather to be wedged between the upper portion of the guide belt 13 and the conveyor belt 4. At the same time, the lower guide roller 11 is relatively close to the first conveying roller 2, hence it does not project too much below the latter, not even when the first guide unit 8 is arranged in the second position of Fig. 9, hence the first conveying roller 2 can be kept relatively close to the rest surface 14, to advantage of the guiding accuracy of the leather 16 between the first guide unit 8 and the rest surface 14.

Preferably but not necessarily, the two guide rollers 11 and 12 have the same diameter.

As regards the first operating means 10 that rotates the first guide unit 8, they comprise an actuator 23, seen in Figs. 2, 3, 8 and 9, that acts on a support body 24 belonging to the first guide unit 8 and that is rotatable according to the first driving axis Yl.

Preferably, the above mentioned support body 24 is a flange hinged on the support structure 25 mentioned beforehand.

As regards the actuator 23, preferably it is a hydraulic or pneumatic cylinder whose ends are connected to, respectively, the support structure 25 and the support body 24 in such a way that an elongation or a shortening of the cylinder cause a corresponding rotation of the support body 24 in a respective direction.

In variant embodiments of the invention, the actuator 23 may be a motor, for example of electric or hydraulic type, interposed between the support body 24 and the support structure 25.

Still preferably, the lay-down device 1 comprises a second conveying roller 3 rotatably mounted around a second rotation axis X2 parallel to the first rotation axis XI of the first conveying roller 2. A second portion of the conveyor belt 4 is wounded around the second conveying roller 3 in such a way as to keep the belt 4 stretched between the two conveying rollers 2 and 3. Clearly, the conveying surface 5 is defined by the surface of the upper portion of the conveyor belt 4 comprised between the two rollers 2, 3.

It is understood that the above mentioned second conveying roller 3 allows the lay-down device 1 to be used to lay down a second leather 17 on a second rest surface 15 through a movement of the conveying surface 5 in a direction opposite to the previous one, as shown in Figs. 10 and 11. As a consequence, advantageously, the configuration just disclosed allows to increase the capacity and/or the flexibility of the lay-down device 1, for example by using the two rest surfaces 14, 15 to lay down leathers of two different types, or according to two different lay-down modes, as it will be disclosed in more detail later.

Preferably, the second conveying roller 3 is connected to the support structure 25 so as to be moved integrally together with the first conveying roller 2 by the second motorization means 7. As a consequence, the support structure 25, the two rollers 2 and 3, and the conveyor belt 4, in their whole, define a conveying carriage that may be translated as a single device by the second motorization means 7.

Preferably, the lay-down device 1 further comprises a second guide unit 9, shown schematically in Fig. 1, configured to keep the second leather 17 in contact with a first section of the above mentioned second portion of the belt 4 while the latter is being moved towards the second conveying roller 3.

It is understood that the second guide unit 9 is symmetrical to the first guide unit 8, and it has a similar function in respect to the second conveying roller 3 as the function of the first guide unit 8 in respect to the first conveying roller 2.

In particular, the second guide unit 9 allows to cause a corresponding deviation of the second leather 17 relative to the conveying direction Z at the level of the second conveying roller 3.

Similarly to the first guide unit 8, the lay-down device 1 comprises second operating means 10a to cause the rotation of the second guide unit 9 around a second driving axis Y2 parallel to the second rotation axis X2. What it has been already disclosed for the first guide unit 8 is also applicable to the second guide unit 9.

The said two guide units 8 and 9 also belong to the above mentioned conveying carriage, that is moved as a single unit by the second motorization means 7.

Preferably, the lay-down device 1 further comprises a driving unit, not shown in the drawings but in itself known, suited to change the vertical position of the rest surfaces 14 and 15 relative to the conveying rollers 2, 3. Advantageously, the above mentioned driving unit allows to keep the distance between the conveying rollers 2, 3 and the last leather on each stack - which acts as a rest surface for the next leather - unchanged, regardless of the height of the corresponding stack, in order that each leather is guided always in the same way.

Preferably, the lay-down device 1 comprises a logic control unit, not shown in the drawings but in itself known, that coordi natively operates the first motorization means 6, the second motorization means 7, the first operating means 10, the second operating means 10a, and the driving unit.

Preferably, sensors are further provided that are configured to measure the parameters of each leather arranged on the conveying surface 5, among which are the dimensions, the thickness, etcetera, connected to the above mentioned logic control unit to, advantageously, allow to reach an high degree of automation of the lay-down device 1.

The guide units 8 and 9 disclosed so far are based on a guide surface arranged in contact with the leathers 16 and 17, but different arrangements may be envisaged, provided the guide units are suited to keep the leathers in contact with the conveying rollers 2, 3. For example, in a different embodiment, the guide units 8 and 9 may use air flows to push, or pull, the leathers in order to keep them in contact with the rollers.

The lay-down device 1 above disclosed allows to lay down the leathers 16 and 17 on corresponding rest surfaces 14, 15 through the method of the invention.

First of all, the above mentioned method comprises an operation for placing the first leather 16 on the conveying surface 5.

The placement operation just mentioned may occur, for example, through the use of a feeding unit, superimposed on the conveyor belt 4, and also being part of the lay-down device 1. As seen in Fig. 1, the feeding unit comprises a feeding belt 18 stretched between a first feeding roller 19 and a second feeding roller 20, and defining an upper surface on which the leather 16 exiting the machine or the processing plant is laid down. The feeding belt 18 is moved by motorization means 21 in such a way as to move the first leather 16 arranged thereon towards the conveyor belt 4 according to a feeding direction K, the feeding direction being oriented from the second feeding roller 20 towards the first feeding roller 19.

Preferably, the feeding belt 18 is slightly sloped downwards in the above mentioned feeding direction K.

Still preferably, the previously mentioned sensors are arranged to face the feeding belt 18, with the advantage that they do not interfere with the movement of the conveyor belt 4 during occurrence of the lay-down operation of the leather 16 on the rest surface 14.

The transfer of the leather 16 from the feeding belt 18 to the conveying surface 5 occurs through a simultaneous movement of the two elements in concordant directions and at substantially equal speeds.

Preferably, the advancement of the conveying surface 5 occurs through the action of the first motorization means 6 associated to the first conveying roller 2. In this case, before the leather 16 is transferred from the feeding belt 18 to the conveying surface 5, the second motorization means 7 translates the first conveying roller 2 such that the conveyor belt 4 extends beyond the first feeding roller 19 for a lenght sufficient to entirely receive the first leather 16, according to the configuration shown in Fig. 1. After that, the translation of the first conveying roller 2 is stopped and, as seen in Fig. 4, the feeding belt 18 is moved to cause the first leather 16 to move towards the conveyor belt 4 according to the feeding direction K, while at the same time the conveyor belt 4 is moved by the first motorization means 6 to cause the conveying surface 5 to advance in the conveying direction Z.

According to a variant embodiment of the method, the advancement of the conveying surface 5 occurs through the action of the second motorization means 7. In this case, the first conveying roller 2 is firstly positioned next to the first roller 19 of the feeding belt 18. Then, during the movement of the feeding belt 18 according to the feeding direction K, the second motorization means 7 translate the first conveying roller 2 according to the movement direction W. Therefore, in the second variant embodiment, the above mentioned advancement is accomplished through a translation of the first conveying roller 2, which does not rotate, instead as in the first variant embodiment, where the advancement of the conveying surface 5 is accomplished through a rotation of the first conveying roller 2, which remains in a fixed position.

In both cases, the feeding operation is continued until the leather 16 is completely positioned on the conveying surface 5, as shown in Fig. 5.

Clearly, it is also possible to transfer the leather 16 on the conveying surface 5 through a combination of the two variants just disclosed.

After the first leather 16 has been positioned on the conveying surface 5, the first motorization means 6 are driven until bringing the leather in the operating area of the first guide unit 8, as shown in Fig. 6.

Preferably, the feeding unit is configured to allow changing the distance of the first feeding roller 19 from the conveyor belt 4. Advantageously, the configuration just disclosed allows, on the one hand, to arrange the feeding belt 18 close to the conveyor belt 4 during the operation of positioning the leather 16, advantageously limiting possible wrinkles on the leather 16 during positioning, and, on the other hand, to move the feeding belt 18 away before the next lay-down operation of the leather 16 on the rest surface 14, thus avoiding that the belt may interfere with the movement of the conveyor belt 4, hence of the leather 16, below the feeding belt 18. Once the leather 16 has been positioned on the conveying surface 5, the first motorization means 6 and the second motorization means 7 are simultaneously operated to cause, respectively, a first movement of the conveying surface 5 towards the first conveying roller 2 according to the conveying direction Z, that is achieved by rotating the first conveying roller 2, and a second movement of the first conveying roller 2 according to the movement direction W in order to lay down the leather 16 on the underlying first rest surface 14, as shown in Fig. 7. The operation just disclosed occurs by maintaining the same magnitude of the speeds of the first movement and of the second movement.

During the above mentioned lay-down operation, a further operation is envisaged in which the first operating means 10 are driven in such a way that the first guide unit 8 is rotated from the first position, as previously defined and shown in Fig. 8, to the second position, shown in Fig. 9.

As a consequence of the above mentioned rotation, a first phase of the operation for laying down the first leather 16 on the first rest surface 14 occurs with the first guide unit 8 arranged in the first position, while a further second phase of lay-down operation occurs with the first guide unit 8 arranged in the second position.

It is understood that the arrangement of the first guide unit 8 in the first position during the first phase of the lay-down operation facilitates the approaching of the leather 16 to the first guide unit 8, hence facilitates the guidance of the leather, while the rotation of the first guide unit 8 during the second phase of the operation allows a more accurate guiding of the final area of the leather 16, thus preventing possible overturning of the same.

If the first guide unit 8 is of the contactless type, the above mentioned rotation may occur while the conveying surface 5 is moving, hence without interfering with, nor slowing down, the lay-down operation.

The same possibility can be also achieved with a first guide unit 8 of the contact type, as the one previously disclosed, provided the first guide roller 11 receives the rotation directly or indirectly from the conveyor belt 4, because, in this case, the first guide roller 11 remains always synchronized with the first conveying roller 2, hence with the conveyor belt 4, also during rotation of the first guide unit 8 around the driving axis Yl.

What has been just disclosed can be achieved, for example, by connecting the first guide roller 11 to the first conveying roller 2 through the previously mentioned toothed elements, or by connecting it to the roller 2 or to the conveyor belt 4 through the friction elements, previously disclosed as well.

In the lay-down operation shown in Figs. 6 and 7, the movements of the two motorization means 6 and 7 in the corresponding directions Z and W occur according to respective opposite directions, that are indicated in the drawings by corresponding oriented arrows. In this way, the upper surface of the conveyor belt 4 remains substantially still with respect to the first rest surface 14, hence achieving a direct lay down, i.e., without overturning of the leather.

In a variant embodiment of the method, the simultaneous operation of the first motorization means 6 and the second motorization means 7 may occur in such a way that the first movement of the first leather 16 and the second movement of the first conveying roller 2 occur in mutually concordant directions, so as to cause an overturned lay-down of the leather 16 on the first rest surface 14 to occur. In this latter variant embodiment, because the lay-down of leather 16 occurs in a direction that is opposite with respect of the previous case, it is necessary, before proceeding with the above mentioned simultaneous operation of the motorization means 6 and 7, to move the conveying carriage, comprising the two conveying rollers 2, 3 and the conveyor belt 4, in the opposite direction with respect to the direction of movement of the conveying surface 5 during the above mentioned initial placement of the leather 16.

The overturned mode for laying down the first leather 16 on the first rest surface 14 above disclosed occurs in a symmetrical way compared to what is shown in Figs. 10 and 11, which, in fact, refer to the lay-down operation of a second leather 17 on the second rest surface 15 through the second conveying roller 3.

The latter lay-down operation is performed after arranging the second leather 17 on the conveyor belt 4, in a similar way as it has been disclosed previously for the first leather 16.

The first motorization means 6 are then operated until bringing the second leather 17 in the operating area of the second guide unit 9.

After that, the first motorization means 6 and the second motorization means 7 are simultaneoulsy operated to cause, respectively, a first movement of the conveying surface 5 towards the second conveying roller 3 according to the conveying direction Z, and a second movement of the second conveying roller 3 according to the conveying direction Z, in such a way that the second leather 17 is laid down on the second rest surface 15, as seen in Figs. 10 and 11.

Similarly to the lay-down obtained through the first guide unit 8, the lay-down process just disclosed also envisages driving the second operating means 10a in such a way as to rotate the second guide unit 9 from the corresponding first position, shown in Fig. 10, to the second position, shown in Fig. 11, and achieving similar effects as those already previously disclosed for the rotation of the first guide unit 8.

It is understood that the second guide unit 9 can also lay down the second leather 17 in direct mode, i.e. without overturning of the leather 17, similarly as what has been previously disclosed.

From what has been disclosed, it is understood that the method of the invention allows to lay down a plurality of leathers 16, 17 on each rest surface 14, 15, either in direct mode and in overturned mode.

It is also possible that the leathers are laid down on each rest surface, alternately, in direct mode and in overturned mode, in order to avoid that the side of a leather intended to remain visible during use, called "grain side", comes to be arranged in contact with the side of a second leather intended to remain hidden, called "flesh side", to the end of preserving the grain side.

In fact, the lay-down device 1 allows to lay down each leather 16, 17 on any one of the two rest surfaces 14, 15 in any one of the two direct and overturned modes, according to the needs of the user.

It is understood that more than two rest surfaces may be provided. Clearly, the lay down of a leather on a specific rest surface requires a convenient arrangement of the conveying surface 5 with respect to the above mentioned rest surface prior to the lay-down operation.

From what has been disclosed above, it is understood that the lay-down device and the method of the invention achieve the preset aims.

In particular, the rotating guide units allow to guide the leather in a better way compared to the lay-down devices of know kind, given the same operating conditions.

As a consequence, the leather can be laid down more quickly compared to the lay-down devices of known kind, without increasing the amount of folds and wrinkles.

Moreover, the possibility to rotate the guide units allows to guide the leather in a differentiated way, according to the phase in the lay-down process, the type and dimensions of the leather, and the lay-down mode, direct or overturned.

The invention is susceptible of changes and variants all included in the inventive concept expressed in the enclosed claims. In particular, the elements of the invention can be replaced by other elements technically equivalent.

Moreover, one or more elements of a specific embodiment of the invention that are technically compatible with another specific embodiment of the invention can be introduced in the latter in addition to, or in replacement of, elements of the latter. Where technical elements specified in the claims are followed by reference signs, those reference signs are included for the sole purpose of improving the understanding of the invention, hence they do not imply any limitation in the claimed scope of protection.

Claims

1. Device (1) for laying down leathers (16, 17), comprising: a first conveying roller (2) rotatably mounted around a first rotation axis (XI); a conveyor belt (4) defining a conveying surface (5) to support a leather (16, 17), said conveyor belt (4) being provided with a first portion (4a) wrapped around said first conveying roller (2); first motorization means (6) to rotate said first conveying roller (2) around said first rotation axis (XI) in such a way as to move said conveying surface (5) according to a conveying direction (Z) orthogonal to said first rotation axis (XI); second motorization means (7) to move said first conveying roller (2) according to a movement direction (W) orthogonal to said first rotation axis (XI) relative to a rest surface (14) arranged below said device (1); a first guide unit (8) cooperating with said conveyor belt (4) to maintain said leather (16, 17) in contact with a first section (4b) of said first portion (4a) during movement of said conveying surface (5) towards said first conveying roller (2) in such a way as to cause a corresponding deviation of said leather (16, 17) from said conveying direction (Z); first operating means (10) to cause rotation of said first guide unit (8) around a first driving axis (Yl) parallel to said first rotation axis (XI) between a first position and a second position in such a way as to change the length of said first section (4b) and, in turn, the extent of said deviation of said leather (16, 17) between, respectively, a minimum value and a maximum value; characterized in that said second motorization means (7) are configured to move said first conveying roller (2) according to said movement direction (W) independently of the movement of said conveying surface (5) caused by said first motorization means (6), in such a way as to change the position where a first leather (16) of said leathers (16, 17) is laid down on said rest surface (14).

2. Device (1) according to claim 1, characterized in that said first motorization means (6) and said second motorization means (7) are configured in such a way that their combined operation causes said first leather (6) to be laid down on said rest surface (14).

3. Device (1) according to any preceding claim, characterized in that said said movement direction (W) is parallel to said conveying direction (Z).

4. Device (1) according to any preceding claim, characterized in that said rest surface (14) is horizontal.

5. Device (1) according to any preceding claim, characterized in that said first operating means (10) are configured in such a way that, when said first guide unit (8) is arranged in said second position, said first section (4b) extends to a lower height with respect of said first rotation axis (XI).

6. Device (1) according to any preceding claim, characterized in that said first guide unit (8) comprises a first guide roller (11) rotatably mounted around a first guide axis (11a) parallel to said first rotation axis (XI) and a guide belt (13) comprising at least a first portion (13a) wrapped around said first guide roller (11), said guide belt (13) being faced to said first portion (4a) of said conveyor belt (4) in such a way as to be arranged in contact with said leather (16, 17) to maintain it in contact with said first section (4b) of said first portion (4a) of said conveyor belt (4).

7. Device (1) according to claim 6, characterized in that said first guide roller (11) is operatively associated to said first conveying roller (2) in such a way as to move said guide belt (13) at the same speed of said conveyor belt (4).

8. Device (1) according to any claim 6 or 7, characterized in that said first guide unit (8) comprises a second guide roller (12) rotatably mounted around a second guide axis (12a) parallel to, and at a distance from, said first guide axis (11a), said guide belt (13) being wrapped around said second guide roller (12) in such a way as to exhibit an intermediate portion (13b) that is not in contact with any one of said first guide roller (11) and second guide roller (12), said first guide roller (11) and second guide roller (12) being arranged, with respect of said first driving axis (Yl), in such a way that a first area of said guide belt (13) closest to said conveyor belt (4) belongs to said intermediate portion (13b) at least when said first guide unit (8) is arranged in a position comprised between said first position and said second position.

9. Device (1) according to claim 8, characterized in that said first guide roller (11) and second guide roller (12) are arranged in such a way that the part of said intermediate portion (13b) that is arranged above said first area is longer than the part arranged below said first area.

10. Device (1) according to any preceding claim, characterized in that said first driving axis (Yl) coincide with said first rotation axis (XI).

11. Device (1) according to any preceding claim, characterized in that it comprises a second conveying roller (3) rotatably mounted around a second rotation axis (X2) parallel to said first rotation axis (XI) of said first conveying roller (2), a second portion of said conveyor belt (4) being wrapped around said second conveying roller (3).

12. Device (1) according to claim 11, characterized in that it comprises a second guide unit (9) configured to maintain said leather (16, 17) in contact with a first section of said second portion of said conveyor belt (4) during movement of said conveying surface (5) towards said second conveying roller (3) in such a way as to cause a corresponding deviation of said leather (16, 17) from said conveying direction (Z), said device (1) comprising second operating means (10a) to cause rotation of said second guide unit (9) around a second driving axis (Y2) parallel to said second rotation axis (X2).

13. Method for laying down leathers (16, 17) on a rest surface (14, 15) by means of a device (1) according to any preceding claim, comprising the following operations: placing a first one of said leathers (16) on said conveying surface (5); driving said first motorization means (6) until bringing said first leather (16) in the operating area of said first guide unit (8); simultaneously driving said first motorization means (6) and second motorization means (7) so as to cause, respectively, a first movement of said conveying surface (5) towards said first conveying roller (2) according to said conveying direction (Z), and a second movement of said first conveying roller (2) according to said movement direction (W) so as to lay down said first leather (16) on said first rest surface (14); driving said first operating means (10) during said simultaneous driving in such a way as to rotate said first guide unit (8) from said first position to said second position.

14. Method according to claim 13, characterized in that said simultaneous driving is done in such a way that said first movement of said first leather (16) and said second movement of said first conveying roller (2) occur according to mutually concordant directions, so as to cause overturning of said first leather (16) during its laying down on said first rest surface (14).

15. Method according to any claim 13 or 14, characterized in that said device (1) is made according to claim 12, said method comprising the following further operations: placing a second one of said leathers (17) on said conveyor belt (4); driving said first motorization means (6) until bringing said second leather (17) in the operating area of said second guide unit (9); causing a second simultaneously driving of said first motorization means (6) and second motorization means (7) so as to cause, respectively, a first movement of said conveying surface (5) towards said second conveying roller (3) according to said conveying direction (Z) and a second movement of said second conveying roller (3) according to said conveying direction (Z) so as to lay down said second leather (17) on a second rest surface (15) arranged below said device (1) and placed aside to said first rest surface (14) according to said movement direction (W); driving said second operating means (10a) during said second simultaneous driving in such a way as to rotate said second guide unit (9) from said first position to said second position.