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Title:
FOLDING DEVICE, FOLDING PLANT, AND PROCESS OF FOLDING
Document Type and Number:
WIPO Patent Application WO/2017/182901
Kind Code:
A1
Abstract:
The present invention refers to a folding device (1) for semi-finished products (50) of sheet material moving along a predetermined advancement direction (A). The folding device comprises: a supporting frame (2), a lower tool (3) comprising at least one base portion (4) which has a supporting surface (5) configured for receiving and supporting the moving semi-finished product (50) and a lower blowing device (6) configured for ejecting a gas flow towards the moving semi-finished product (50) along the advancement direction (A) and for enabling a first fold of at least one longitudinal end sheet (60) of the semi-finished product (50). Moreover, the folding device comprises an upper tool (9) substantially facing the lower tool (3) along a gas flow emission direction from the lower blowing device (6), the upper tool (9) comprises a guiding element (10) having a descending section (10a) configured for developing by approaching to the lower tool (3) along the advancement direction (A) of the semi-finished product (50). The guiding element (10) is configured for contacting the longitudinal end sheet folded by the lower blowing device (6) for enabling a further fold of said longitudinal end sheet (60).

Inventors:
BRESSAN, Michel (Via Bidino 18, Induno Olona, 21056, IT)
GANDOLLA, Alberto (Via Sangiorgio, 47 B, Induno Olona, 21056, IT)
BRESSAN, Alessio (Via Montello 29, Varese, 21100, IT)
Application Number:
IB2017/051862
Publication Date:
October 26, 2017
Filing Date:
March 31, 2017
Export Citation:
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Assignee:
I.G.B. S.R.L. (Via Pontaccio 14, Milano, 20121, IT)
International Classes:
B31B50/00; B31B50/36; B31B50/585
Attorney, Agent or Firm:
PONZELLINI, Gianmarco (Via L. Mascheroni 31, Milano, I-20145, IT)
Download PDF:
Claims:
C L A I M S

1 . Device (1 ) for folding semi-finished products (50) of sheet material moving along a predetermined advancement direction (A), said folding device (1 ) comprising:

> at least one supporting frame (2) associable to a fixed structure (101 ) of a folding plant (100) configured for moving the semi-finished product (50) along the advancement direction (A),

> at least one lower tool (3) comprising:

o at least one base portion (4) extending along a longitudinal direction between a first and second end portions (4a, 4b), said base portion (4) comprising a supporting surface (5) configured for receiving and supporting the moving semi-finished product (50),

o at least one lower blowing device (6) comprising at least one channel (7) having an ejection opening (8) arranged substantially at the supporting surface (5) of the base portion (4), said lower blowing device (6) being configured for emitting a gas flow towards the semi-finished product (50) moving along the advancement direction (A) and for enabling a first fold of at least one transversal end sheet of the semi-finished product (50),

> at least one upper tool (9) substantially facing the lower tool (3) according to a gas flow emission direction from the lower blowing device (6), said upper tool (9) comprising at least one guiding element (10) developing along a development direction configured for extending, under a condition of use of the folding device (1 ), parallel to the advancement direction (A) of the semi-finished product (50), said guiding element (10) comprising at least one descending section (10a) configured for developing by approaching to the lower tool (3) according to the advancement direction (A) of the semi-finished product (50), the guiding element (10) being configured for contacting the transversal end sheet folded by the lower blowing device (6) for enabling a further fold of said transversal end sheet.

2. Device according to claim 1 , wherein the descending section (10a) of the guiding element (10) is configured for being arranged immediately downstream the ejection opening (8) of the lower blowing device (6) according to the advancement direction (A) of the semi-finished product (50),

optionally wherein the descending section (10a) and ejection opening (8) are located at a predetermined minimum distance (D1 ) from each other according to the development direction of the guiding element (10), particularly wherein said minimum distance is less than 500 mm, still more particularly is comprised between 5 and 150 mm,

wherein the descending section (10a) comprises a sloping section, particularly a rectilinear one, defining a predetermined angle with the supporting surface (5) less than 70°, particularly less than 45°, still more particularly comprised between 5° and 30°; said angle being subtended between the descending section and the supporting surface and being facing the ejection opening of the lower blowing device.

3. Device according to anyone of the preceding claims, wherein the ejection opening (8) of the lower blowing device (6) is interposed between the first and second end portions (4a, 4b) of the base portion (4), wherein the guiding element (10) extends to the second end portion (4b) of the base portion (4).

4. Device according to anyone of the preceding claims, wherein the lower blowing device (6) comprises a plurality of channels (7) each of them exhibits an ejection opening (8) disposed substantially at the supporting surface (5) of the base portion (4), said lower blowing device (6) being configured for emitting a respective gas flow from each ejection opening (8) towards the semi-finished product (50) moving along the advancement direction (A) and for enabling a first fold of at least one transversal end sheet of the semi-finished product (50), optionally wherein the lower blowing device (6) comprises a number of channels (7) and of respective ejection openings equal to or comprised between 1 and 10, particularly equal to or comprised between 2 and 6.

5. Device according to anyone of the preceding claims, wherein the descending section (10a) extends between a first end (10b) - facing the ejection opening (8) of the lower blowing device (6) - and a second end (10c) spaced and opposite to the first end (10b), the first and second ends (10b, 10c) having a predetermined minimum distance along the development direction of the guiding element (10) in order to define a length (D3) of the descending section (10a), particularly said length (D3) being greater than 5 mm, still more particularly is comprised between 20 and 300 mm.

6. Device according to the preceding claim, wherein the guiding element (10) comprises at least one abutment section (10d) connected, optionally joined in one piece, to the first end (10b) of the descending section (10a) and extending along a rectilinear direction from a part opposite to the second end (10c) of the descending section, particularly the abutment section (10d) extends substantially parallel to the supporting surface (5) of the base portion (4) of the lower tool (3).

7. Device according to claim 5 or 6, wherein the guiding element (10) comprises at least one pressing section (1 Of) connected, optionally unitarily connected, to the second end (10c) of the descending section (10a) and extending along a rectilinear direction opposite to the first end (10b) of the descending section (10a), particularly the pressing section (1 Of) substantially extends parallel to the supporting surface (5) of the base portion (4) of the lower tool (3).

8. Device according to anyone of the preceding claims, wherein the lower blowing device (6) is connectable to a gas supplying unit (102), said lower blowing device (6) comprising at least one flow adjusting element (1 1 ), particularly a solenoid valve, configured for defining a first operative condition of the lower blowing device (6) wherein the same emits a gas flow from the ejection opening (8), said flow adjusting element (1 1 ) being further configured for defining a second operative condition of the lower blowing device (6) wherein the same prevents the emission of gas flow from the ejection opening (8),

wherein the flow adjusting element (1 1 ) is configured for alternatively defining the first and second operative conditions as a function of positions taken by the semifinished product (50) with respect to the ejection opening (8);

wherein the folding device (1 ) comprises:

> at least one sensor (12) arranged upstream the ejection opening (8) of the lower blowing device (6) according to the advancement direction of the semi- finished product (50), said sensor (12) being configured for emitting a control signal associated to the detection of a semi-finished product moving along the advancement direction (A),

at least one control unit (13) connected to the sensor and to the flow adjusting element (1 1 ), said control unit being configured for:

o receiving from the sensor (12) the control signal,

o determining, as a function of said signal received by the sensor, the relative position of the semi-finished product (50) with respect to the position of the ejection opening (8),

o commanding, as a function of the semi-finished product position with respect to the ejection opening and as a function of a moving speed of the semi-finished product along the advancement direction (A), the first and second operative conditions of the flow adjusting element (1 1 ) of the lower blowing device (6) according to sequences spaced so that the gas flow emitted at time intervals, can enable a first fold of at least one transversal end sheet of the semi-finished product (50).

9. Device according to anyone of the preceding claims, wherein the upper tool (9) comprises at least one upper blowing device (16) comprising at least one channel (17) having an ejection opening (18) interposed between the supporting surface (5) of the base portion (4) and guiding element (10), said upper blowing device (16) being configured for emitting from the respective ejection opening, a gas flow having a direction substantially parallel to the advancement direction (A) of the semi-finished product (50) and configured for enabling a second fold of the transversal end sheet of the semi-finished product (50) previously folded by the lower blowing device (6).

10. Device according to claim 9 when this latter depends to claim 8, wherein the upper blowing device (16) is connectable to the gas supplying unit (102), said upper blowing device (16) comprising at least one flow adjusting element (19), particularly a solenoid valve, configured for defining a first operative condition of the upper blowing device (16) wherein the same emits a gas flow from the ejection opening (18), said flow adjusting element (19) being further configured for defining a second operative condition of the lower blowing device (16) wherein the same prevents the emission of gas flow from the ejection opening (18), wherein said flow adjusting device (19) of the upper blowing device (16) is configured for alternatively defining the first and second operative conditions as a function of positions taken by the semi-finished product (50) with respect to the ejection opening (8) of the lower blowing device (6),

wherein the control unit (13) is connected to the flow adjusting element (19) of the upper blowing device (16), said control unit (13) being configured for:

o receiving from the sensor (12) the control signal,

o determining, as a function of said signal received from the sensor, the relative position of the semi-finished product (50) with respect to the position of the ejection opening (8) of the lower blowing device (6),

o commanding, as a function of the semi-finished product position with respect to the ejection opening of the lower blowing device and as a function of a moving speed of the semi-finished product along the advancement direction (A), the first and second operative conditions of the upper blowing device (16) according to sequences spaced so that the gas flow emitted at time intervals can enable a second fold of the transversal end sheet of the semi-finished product (50).

1 1 . Device according to the preceding claim, wherein the control unit (13) is configured for determining, as a function of the signal received from the sensor and as a function of the moving speed of the semi-finished product (50) along the advancement direction (A), the second operative condition of the lower and upper blowing device (6, 16), particularly the control unit (13) is configured for:

> commanding, as a function of the semi-finished product position with respect to the ejection opening of the lower blowing device and as a function of an advancement speed of the semi-finished product along the advancement direction (A), the second operative condition of the lower blowing device, > commanding, as a function of the semi-finished product position with respect to the ejection opening of the lower blowing device and as a function of an advancement speed of the semi-finished product along the advancement direction (A), the second operative condition of the flow adjusting element (19) of the upper blowing device, the control unit (13) being configured for commanding the second operative condition of the flow adjusting element (19) of the upper blowing device (16) following the command of the second operative condition of the flow adjusting element (1 1 ) of the lower blowing device. 12. Device according to anyone of the preceding claims, wherein the base portion (4) and lower blowing device (6) of the lower tool (3) define respectively a first base portion (4) and a first lower blowing device (6), the guiding element (10) of the upper tool (9) defining a first guiding element (10),

wherein the folding device (1 ) further comprises:

> at least one second base portion (20) located downstream the first base portion (4) according to the advancement direction of the semi-finished product (50), said second base portion (20) extending along a longitudinal direction between a first and second end portions (20a, 20b), said second base portion (20) comprising a supporting surface (21 ) configured for receiving and supporting the moving semi-finished product (50),

> at least one second lower blowing device (22) located downstream the first lower blowing device (6) according to the advancement direction of the semifinished product (50), said second lower blowing device (22) comprising at least one channel (23) having an ejection opening (24) arranged substantially at the supporting surface (21 ) of the second base portion (20), said second lower blowing device (22) being configured for emitting a gas flow in the direction of the semi-finished product (50) moving along the advancement direction (A) and for enabling a first fold of at least one transversal end sheet of the semi-finished product (50),

> at least one second guiding element (25) arranged downstream the first guiding element (10) along the advancement direction of the semi-finished product (50), said second guiding element (25) developing along a development direction configured for extending, under a condition of use of the folding device (1 ), parallel to the advancement direction (A) of the semi- finished product (50), said second guiding element (25) comprising at least one descending section (25a) configured for developing by approaching to the second base portion (20) along the advancement direction (A) of the semifinished product (50), the second guiding element (25) being configured for contacting the transversal end sheet folded by the second lower blowing device (22) for enabling a further fold of said transversal end sheet.

13. Device according to the preceding claim, wherein the upper blowing device (16) of the upper tool (9) defines a first upper blowing device,

wherein the folding device (1 ) further comprises a second upper blowing device (30) arranged substantially above the ejection opening of the second lower blowing device (22), particularly the second upper blowing device (30) is aligned with the second lower blowing device (22) along the ejection direction of the gas flow from this latter,

the second upper blowing device comprising at least one channel (31 ) having an ejection opening (32) interposed between the supporting surface (21 ) of the second base portion (20) and the second guiding element (10), said second upper blowing device (30) being configured for emitting from the respective ejection opening, a gas flow having a direction substantially parallel to the advancement direction (A) of the semi-finished product (50) and configured for enabling a second fold of the transversal end sheet of the semi-finished product (50) previously folded by the second lower blowing device (22),

wherein the second upper blowing device (30) is configured for emitting a gas flow towards the descending section (25a) of the second guiding element (25).

14. Folding plant (100) comprising:

> at least one fixed structure (101 ),

> at least one transporting member (103) engaged with the fixed structure (101 ) and configured for engaging at least one semi-finished product (50) of sheet material and for moving it along an operative path along an advancement direction (A), > at least one folding device (1 ) according to anyone of the preceding claims, the folding device (1 ) being constrained to the fixed structure (101 ) at the operative path, said folding device being configured for receiving the moving semi-finished product (50) and for enabling to fold at least one transversal end sheet of said semi-finished product (50).

15. Process of folding a semi-finished product (50) of sheet material by a folding device (1 ) according to anyone of the preceding claims from 1 to 13, the process comprising at least the following steps:

> moving a flat semi-finished product (50) of sheet material along an advancement direction (A), said semi-finished product being of a type comprising at least one central sheet (51 ) and at least one transversal end sheet positioned in front or in the back of the central sheet with respect to the advancement direction (A) of the semi-finished product (50),

> emitting a gas flow towards the flat semi-finished product (50) by the lower blowing device (6) during the movement of said semi-finished product (50) along the advancement direction (A), the step of emitting the gas flow occurring during the passage of the transversal end sheet at the ejection opening (8) of said transversal end sheet, said emission step enabling a first fold of the transversal end sheet with respect to the central sheet away from the ejection opening (8) of the lower blowing device (6),

> moving the semi-finished product (50) along the advancement direction (A) so that the folded transversal end sheet contacts the descending section (10a) of the guiding element (10) which enables a further fold of said transversal end sheet above the central sheet, optionally, emitting a gas flow by the upper blowing device (16) simultaneously or immediately following the step of emitting the gas flow from the lower blowing device (6), the gas flow emitted by the upper blowing device (16) hitting the transversal end sheet folded by the lower blowing device (6) for enabling a further fold of said transversal end sheet, wherein the gas flow emitted by the upper blowing device (16) exhibits an emission direction substantially parallel and a way opposite to the advancement direction (A) of the semi-finished product (50). 16. Process according to the preceding claim, wherein the semi-finished product (50) comprises a front transversal end sheet and a rear transversal end sheet opposite to each other with respect to the central sheet of the of the semi-finished product (50), the step of emitting the gas flow by the lower blowing device (6) enabling to fold the front transversal end sheet,

wherein the process further comprises the following steps:

> following the movement of the semi-finished product (50) through the guiding element (10) for folding the front transversal end sheet, moving the same semi-finished product along the advancement direction (A) exiting said guiding element (10) and entering the second guiding element (25),

> emitting a gas flow towards the flat semi-finished product (50) by the second lower blowing device (22) during the movement of said semi-finished product (50) along the advancement direction (A), the step of emitting the gas flow occurring upon the passage of the rear transversal end sheet at the ejection opening (24) of said rear transversal end sheet (60), said emission step enabling a first fold of the rear transversal end sheet (60) with respect to the central sheet away from the ejection opening (24) of the second lower blowing device (22),

> moving the semi-finished product (50) along the advancement direction (A) so that the folded rear transversal end sheet (60) contacts the descending section (25a) of the second guiding element (25) which enables the further fold of said rear transversal end sheet above the central sheet (51 ),

> optionally, emitting a gas flow by the second upper blowing device (30) simultaneously or immediately following the step of emitting the gas flow from the lower blowing device (22), the gas flow emitted by the second upper blowing device (30) hitting the rear transversal end sheet folded by the second lower blowing device (22) for enabling the further fold of said transversal end sheet.

Description:
FOLDING DEVICE, FOLDING PLANT, AND PROCESS OF FOLDING

FIELD OF THE INVENTION

The object of the present invention consists in a folding device, folding plant and process of folding, particularly used for processing semi-finished products of paper sheet material. The invention can find an advantageous application in the papermaking field, particularly for making containers, for example destined to the pharmaceutical, cosmetic, and food fields. STATE OF THE ART

In the papermaking field, are known apparatuses and associated methods for making containers of paper material for containing products such as for example drugs, cosmetic and food products. The known solutions comprise the provision of a flat semi-finished product of paper material obtained by die-cutting a sheet; the die-cutting step generates - by cutting - the external perimeter of the semifinished product and - by pressing the sheet itself - a plurality of creasing lines along which the semi-finished product itself is folded for defining the container. The flat semi-finished product, obtained in this way, is then moved to a plant known as folder-gluer plant which enables to move the flat semi-finished product along an advancement direction by one or more conveyor belts. During the movement step, the folder-gluer plant first of all applies glue on predetermined areas of the semi-finished product. Then, the semi-finished product is folded along the longitudinal development thereof, then along an advancement direction of the same.

This folding step is mechanically performed by one or more rotating devices - known as four-corners devices - each of them is provided with a plurality of hooks angularly offset from each other. A four-corners device is configured for rotating about an axis normal to the advancement direction of the semi-finished product so that each hook rotates about the advancement direction of the semi-finished product (which is the same as the advancement direction). Each hook is configured for contacting a rear end portion of the semi-finished product moving along the advancement direction and for folding the rear portion itself above a central or front portion of the semi-finished product.

At the end of the step of folding the semi-finished product, the same is moved along a further plant which enables: to arrange the same according to a three- dimensional configuration in order to define the container, to possibly introduce products inside the container and to fold by rolls and mechanical guides lateral tabs for enabling the closure of the container.

While the known rotating devices (four-corners devices) enable to longitudinally fold the moving semi-finished product along an advancement direction, the Applicant has noted that these devices are not devoid of limitations and disadvantages.

Actually, it is noted that almost all the paper semi-finished products used for obtaining containers, require to fold end portions located both in the rear area and front area of the semi-finished product with respect to the advancement direction of the same. However, according to their structure, the rotating devices are adapted to only enable to fold rear end portions of the semi-finished product: a four-corners device is not capable by itself to fold the front portions. De facto, the known folding systems comprise a first rotating device configured for enabling to fold a rear portion of the semi-finished product. Downstream the first rotating device, the folder-gluer plant comprises a station for rotating the semi-finished product which enables to invert the position of the rear portion with the front one. Downstream the rotating station, along the advancement direction of the semifinished product, the folder-gluer plant comprises a further rotating device enabling to fold again the rear portion (before the front portion the position thereof being inverted by the rotating station) of the semi-finished product: in this way, the folder-gluer plant enables to fold both the transversal end portions of the semifinished product by means of the four-corners system.

Therefore, for this configuration, the plant would require two distinct four-corners devices, in between a rotating station is required for enabling to invert the position of the rear and front portions of the semi-finished product. Such configuration negatively affects the overall size of the plant which has an excessive development along the advancement direction of the semi-finished product. The requirement of providing the plant with two four-corners stations and one rotating station further increases the overall costs of the plant and therefore the costs of the products to be manufactured.

A further disadvantage due to the use of rotating devices arises from the structure and operation of the four-corners devices which compel to move the semi-finished products at very low advancement speeds with reference to the throughput of the machine, this condition substantially decreases the manufacturing capabilities of a plant. In addition, it is noted that the rotating device enables to mechanically fold the semi-finished product by pushing the hook on the end portions to be folded; the contact of the four-corners devices on the paper semi-finished product can aesthetically damage this latter.

An embodiment variant of the known plants provides to use the four-corners device for folding rear transversal portions of the semi-finished product, and a spring rotating device known in the art as "spring hook", configured for enabling to fold front transversal portions of the semi-finished product without requiring to invert this latter by the rotating station.

The spring hook comprises a rotating arm disposed on an operative path of the semi-finished product; the spring hook defines a type of stop configured for contacting the semi-finished product advancing along the operative path. More particularly, the spring hook comprises an arm having a "L" shape configured for abuttingly receiving the front transversal portion of the semi-finished product; following the contact between the semi-finished product and the rotating device, this latter is configured for hooking the front portion of the semi-finished product and, by a rotating action, to fold such portion above a central portion of the semifinished product. The spring hook, following the passage of the semi-finished product, is configured for moving back to the starting position (in correspondence of the operative path of the semi-finished product) by means of elastic elements. Although the combination of a four-corners device with the spring hook enables to fold the front and rear portions of a semi-finished product avoiding the use of a rotating station, the Applicant has noted that also such solution is not devoid of limitations. De facto, as per the four-corners device, the spring hook has a structure and operation which compel to move the semi-finished product at very low advancement speeds with respect to the throughput of the machine, this condition substantially limits the manufacturing capabilities of the plant. The spring hook forms a mechanical constrain to the advancement movement of the semi-finished product; the front portion of the semi-finished product is folded due to the direct contact with the spring hook which forms a real anvil against which the semi-finished product hits so that it can be folded. The hard contact between the semi-finished product and the spring hook can easily aesthetically damage the semi-finished product; in addition, due to the structure of the spring hook, it cannot be used for folding semi-finished products having fragile parts which could be subjected to aesthetic damages or, at worst, could be torn by the hook. A further disadvantage of the spring hook is that it can only act on an external portion of the semi-finished product and therefore is capable of forming just one fold. OBJECT OF THE INVENTION

Therefore, the object of the present invention consists of substantially solving at least one of the disadvantages and/or limitations of the previous solutions.

A first object of the present invention consists of providing a folding device and an associated process capable of enabling to correctly fold paper semi-finished products - also at high moving speeds of these latter along the advancement direction - without compromising the structurality and appearance of the semifinished product.

Further, it is an object of the present invention to provide a folding device which is simple and easily manufacturable, particularly implementable at low manufacturing costs.

Then, it is an object of the present invention to provide a compact folding device which can be integrated in the present folding plants without requiring complicated modifications of the same; particularly, it is an object of the present invention to provide a folding device which can easily replace the rotating devices of the present folder-gluer plants so that complicated modifications of these latter are not required.

It is a further object of the present invention to provide a folding device and an associated process showing an operation which is substantially flexible and particularly useable for folding different semi-finished products.

Then, it is an object of the present invention to provide a folding process which is fast and substantially flexible which can therefore reduce at the minimum the manufacturing costs.

These and other objects, which will better appear in the following description, are substantially met by a folding device, a folding plant and process of folding according to what is expressed in one or more of the attached claims and/or of the following aspects, considered alone or in any combination with each other or in combination with anyone of the attached claims and/or in combination with anyone of the further aspects or characteristics described in the following.

SUMMARY

The aspects of the invention will be described in the following.

In a 1 st aspect it is provided a device (1 ) for folding semi-finished products (50) of sheet material moving along a predetermined advancement direction (A), said folding device (1 ) comprising:

> at least one supporting frame (2) associable to a fixed structure (101 ) of a folding plant (100) configured for moving the semi-finished product (50) along the advancement direction (A),

> at least one lower tool (3) comprising:

o at least one base portion (4) extending along a longitudinal direction between a first and second end portions (4a, 4b), said base portion (4) comprising a supporting surface (5) configured for receiving and supporting the moving semi-finished product (50),

o at least one lower blowing device (6) comprising at least one channel (7) having an ejection opening (8) arranged substantially at the supporting surface (5) of the base portion (4), said lower blowing device (6) being configured for emitting a gas flow towards the semi-finished product (50) moving along the advancement direction (A) and for enabling a first fold of at least one transversal end sheet of the semi-finished product (50),

> at least one upper tool (9) substantially facing the lower tool (3) according to a gas flow emission direction from the lower blowing device (6), said upper tool (9) comprising at least one guiding element (10) developing along a development direction configured for extending, under a condition of use of the folding device (1 ), parallel to the advancement direction (A) of the semi- finished product (50), said guiding element (10) comprising at least one descending section (10a) configured for developing by approaching to the lower tool (3) according to the advancement direction (A) of the semifinished product (50), the guiding element (10) being configured for contacting the transversal end sheet folded by the lower blowing device (6) for enabling a further fold of said transversal end sheet.

In a 2nd aspect according to the preceding aspect, the descending section (10a) of the guiding element (10) is configured for being arranged immediately downstream the ejection opening (8) of the lower blowing device (6) according to the advancement direction (A) of the semi-finished product (50).

In a 3rd aspect according to the aspect 1 or 2, the descending section (10a) and the ejection opening (8) are positioned at a predetermined minimum distance (D1 ) from each other according to the development direction of the guiding element (10), particularly wherein said minimum distance is less than 500 mm, still more particularly is comprised between 5 and 150 mm.

In a 4th aspect according to anyone of the preceding aspects, the descending section (10a) comprises a sloped section, particularly a rectilinear one, defining a predetermined angle with the supporting surface (5) less than 70°, particularly less than 45°, still more particularly comprised between 5° and 30°; said angle being subtended between the descending section and the supporting surface and facing the ejection opening of the lower blowing device.

In a 5th aspect according to anyone of the preceding aspects, the descending section (10a) extends between a first end (10b) - facing the ejection opening (8) of the lower blowing device (6) - and a second end (10c) spaced and opposite to the first end (10b), the first and second ends (10b, 10c) having a predetermined minimum distance along the development direction of the guiding element (10) in order to define a length (D3) of the descending section (10a), particularly said length (D3) being greater than 5 mm, still more particularly is comprised between 20 and 300 mm.

In a 6th aspect according to the preceding aspect, the first and second ends (10b, 10c) of the descending section (10a) are configured for having a predetermined minimum distance along the emission direction of the gas flow from the lower blowing device (6) in order to define a difference in height (D2) of the descending section (10a), said difference in height being greater than 5 mm, particularly is comprised between 10 and 300 mm, still more particularly is comprised between 10 and 50 mm.

In a 7th aspect according to the aspect 5 or 6, the guiding element (10) comprises at least one abutment section (10d) connected, optionally unitarily connected, to the first end (10b) of the descending section (10a) and extending along a rectilinear direction from a part opposite to the second end (10c) of the descending section, particularly the abutment section (10d) extends substantially parallel to the supporting surface (5) of the base portion (4) of the lower tool (3). In an 8th aspect according to the preceding aspect, the abutment section (10d) has a predetermined minimum distance (D4) from the supporting surface (5) of the base portion greater than 5 mm, particularly comprised between 10 and 300 mm. In a 9th aspect according to anyone of the aspects from 5 to 8, the guiding element (10) comprises at least one pressing section (1 Of) connected, optionally unitarily connected, to the second end (10c) of the descending section (10a) and extending along a rectilinear direction opposite to the first end (10b) of the descending section (10a), particularly the pressing section (1 Of) substantially extends parallel to the supporting surface (5) of the base portion (4) of the lower tool (3).

In a 10th aspect according to the preceding aspect, the pressing section (1 Of) has a predetermined minimum distance (D5) from the supporting surface (5) of the base portion greater than 1 mm, particularly comprised between 1 and 5 mm.

In an 1 1 th aspect according to the aspect 9 or 10, the pressing section (1 Of) extends parallel to the abutment section (10d).

In a 12th aspect according to anyone of the aspects from 9 to 1 1 , the descending section (10a) is interposed between the pressing section (1 Of) and abutment section (10d).

In a 13th aspect according to anyone of the aspects from 5 to 12, the ejection opening (8) of the lower blowing device (6) is interposed between the first and second end portions (4a, 4b) of the base portion (4), the second end portion (4b) of the base portion (4) facing the second end (10c) of the descending section (10a) of the guiding element (10), wherein the guiding element (10) extends to the second end portion (4b) of the base portion (4).

In a 14th aspect according to anyone of the aspects from 5 to 13, the guiding element (10) extends along a development direction substantially parallel to the development direction of this portion (4), between a first and second end portions, the first end portion of the guiding element being arranged at the ejection opening (8) of the lower blowing device while the second end portion of the guiding element (10) being arranged at the second end portion (4b) of the base portion (4).

In a 15th aspect according to anyone of the preceding aspects, the folding device (1 ) comprises at least one adjustment member (14) engaged, on one side, with the supporting frame (2) and, on the other side, with the guiding element (10), said adjustment member (14) being configured for moving the guiding element (10) with respect to the supporting frame (2) along an adjustment direction (R1 ) towards or away from the supporting surface (5) of the base portion (4).

In a 16th aspect according to the preceding aspect, said adjustment direction (R1 ) is substantially parallel to a gas ejection direction from the ejection opening (8). In a 17th aspect according to anyone of the preceding aspects, the folding device (1 ) comprises at least one further adjustment member (15) engaged, on one side, with the supporting frame (2) and, on the other side, with the guiding element (10), said further adjustment member (15) being configured for moving the guiding element (10) with respect to the supporting frame (2) along an adjustment direction (R2) transversal to the development direction of the base portion (4) and transversal to a gas flow ejection direction from the ejection opening (8).

In an 18th aspect according to anyone of the preceding aspects, the lower blowing device (6) comprises a plurality of channels (7), each of them has an ejection opening (8) substantially arranged at the supporting surface (5) of the base portion (4), said lower blowing device (6) being configured for emitting a respective gas flow from each ejection opening (8) towards the semi-finished product (50) moving along the advancement direction (A) and for enabling a first fold of at least one transversal end sheet of the semi-finished product (50), optionally wherein the lower blowing device (6) comprises a number of channels (7) and of respective ejection openings equal to or comprised between 1 and 10, particularly equal to or comprised between 2 and 6.

In a 19th aspect according to anyone of the preceding aspects, the lower blowing device (6) is connectable to a gas supplying unit (102), said lower blowing device (6) comprising at least one flow adjusting member (1 1 ), particularly a solenoid valve, configured for defining a first operative condition of the lower blowing device (6) wherein the same ejects the gas flow from the ejection opening (8), said flow adjusting member (1 1 ) being further configured for defining a second operative condition of the lower blowing device (6) wherein the same prevents the gas flow from being ejected from the ejection opening (8), wherein the flow adjusting member (1 1 ) is configured for alternately defining the first and second operative conditions as a function of positions taken by the semi-finished product (50) with respect to the ejection opening (8).

In a 20th aspect according to the preceding aspect, the folding device (1 ) comprises:

> at least one sensor (12) arranged upstream the ejection opening of the lower blowing device (6) according to the advancement direction of the semi-finished product (50), said sensor (12) being configured for emitting a control signal regarding the detection of a semi-finished product moving along the advancement direction (A),

> at least one control unit (13) connected to the sensor and flow adjusting member (1 1 ), said control unit being configured for:

o receiving the control signal from the sensor (12),

o determining, as a function of said signal received from the sensor, the relative position of the semi-finished product (50) with respect to the position of the ejection opening (8),

o commanding, as a function of the position of the semi-finished product with respect to the ejection opening and as a function of a moving speed of the semi-finished product along the advancement direction (A), the first and second operative conditions of the flow adjusting member (1 1 ) of the lower blowing device (6) according to sequences spaced so that the gas flow ejected at time intervals can enable a first fold of at least one transversal end sheet of the semi-finished product (50).

In a 21 st aspect according to the preceding aspect, the control unit (13) is configured for determining, as a function of the signal received from the sensor and as a function of the moving speed of the semi-finished product (50) along the advancement direction (A), a passage condition of at least one transversal end sheet (60) of the semi-finished product (50) above the ejection opening (8), the control unit (13) being configured for defining the first operative condition of the flow adjusting member (1 1 ) only when the passage condition of at least one transversal end sheet of the semi-finished product (50) above the ejection opening (8) is determined.

In a 22nd aspect according to anyone of the preceding aspects, the upper tool (9) comprises at least one upper blowing device (16) comprising at least one channel (17) having an ejection opening (18) interposed between the supporting surface (5) of the base portion (4) and the guiding element (10), said upper blowing device (16) being configured for ejecting from the respective ejection opening, a gas flow having a direction substantially parallel to the advancement direction (A) of the semi-finished product (50), and configured for enabling a second fold of the transversal end sheet of the semi-finished product (50) beforehand folded by the lower blowing device (6).

In a 23rd aspect according to the preceding aspect, the ejection opening (18) of the lower blowing device (16) is interposed between the ejection opening (8) of the lower blowing device (6) and descending section (10a) of the guiding element (10), the upper blowing device (16) being configured for emitting a gas flow towards the ejection opening (8) of the lower blowing device (6).

In a 24th aspect according to the aspect 22 or 23, the upper blowing device (16) comprises a plurality of channels (17), each of them has an ejection opening (18), said upper blowing device (16) being configured for ejecting, from each of said ejection opening (18), a respective gas flow having a direction substantially parallel to the advancement direction (A) of the semi-finished product (50) for enabling a second fold of the transversal end sheet of the semi-finished product (50), optionally, wherein the upper blowing device (16) comprises a number of channels (17) and of respective ejection openings (18) equal to or comprised between 2 and 10, particularly equal to or comprised between 2 and 6.

In a 25th aspect according to anyone of the aspects from 22 to 24, the ejection opening (18) of the upper blowing device (16) has a minimum distance (D6) from the supporting surface (5) of the base portion (4) less than the minimum distance between the abutment section (10d) of the guiding element (10) and the supporting surface of the base portion (4), particularly the minimum distance (D6) between the ejection opening of the upper blowing device (16) and supporting surface (5) of the base portion (4) is comprised between 1 and 200 mm, still more particularly between 3 and 20 mm.

In a 26th aspect according to anyone of the aspects from 22 to 25, the upper blowing device (16) is connectable to the gas supplying unit (102), said upper blowing device (16) comprising at least one flow adjusting member (19), particularly a solenoid valve, configured for defining a first operative condition of the upper blowing device (16), wherein the same ejects a gas flow from the ejection opening (18), said flow adjusting member (19) being further configured for defining a second operative condition of the lower blowing device (16) wherein the same prevents the gas flow from being ejected from the ejection opening (18), wherein said flow adjusting device (19) of the upper blowing device (16) is configured for alternately defining the first and second operative conditions as a function of positions taken by the semi-finished product (50) with respect to the ejection opening (8) of the lower blowing device (6).

In a 27th aspect according to the preceding aspect, the control unit (13) is connected to the flow adjusting member (19) of the upper blowing device (16), said control unit (13) being configured for:

o receiving the control signal from the sensor (12),

o determining, as a function of said signal received from the sensor, the relative position of the semi-finished product (50) with respect to the position of the ejection opening (8) of the lower blowing device (6),

o commanding, as a function of the position of the semi-finished product with respect to the ejection opening of the lower blowing device, and as a function of a moving speed of the semi-finished product along the advancement direction (A), the first and second operative conditions of the upper blowing device (16) according to sequences spaced so that the gas flow ejected at time intervals can enable a second fold of the transversal end sheet of the semi-finished product (50).

In a 28th aspect according to the preceding aspect, the control unit (13) is configured for determining, as a function of the signal received from the sensor and as a function of the moving speed of the semi-finished product (50) along the advancement direction (A), the second operative condition of the lower and upper blowing devices (6, 16), particularly the control unit (13) is configured for:

> commanding, as a function of the position of the semi-finished product with respect to the ejection opening of the lower blowing device and as a function of an advancement speed of the semi-finished product along the advancement direction (A), the second operative condition of the lower blowing device,

> commanding, as a function of the position of the semi-finished product with respect to the ejection opening of the lower blowing device and as a function of an advancement speed of the semi-finished product along the advancement direction (A), the second operative condition of the flow adjusting member (19) of the upper blowing device, the control unit (13) being configured for commanding the second operative condition of the flow adjusting member (19) of the upper blowing device (16) after commanding the second operative condition of the flow adjusting member (1 1 ) of the lower blowing device.

In a 29th aspect according to anyone of the preceding aspects, the base portion (4) and lower blowing device (6) of the lower tool (3) define respectively a first base portion (4) and a first lower blowing device (6), the guiding element (10) of the upper tool (9) defining a first guiding element (10),

wherein the folding device (1 ) further comprises:

> at least one second base portion (20) arranged downstream the first base portion (4) along the advancement direction of the semi-finished product

(50), said second base portion (20) extending along a longitudinal direction between a first and second end portions (20a, 20b), said second base portion (20) comprising a supporting surface (21 ) configured for receiving and supporting the moving semi-finished product (50),

> at least one second lower blowing device (22) arranged downstream the first lower blowing device (6) along the advancement direction of the semifinished product (50), said second lower blowing device (22) comprising at least one channel (23) having an ejection opening (24) substantially arranged at the supporting surface (21 ) of the second base portion (20), said second lower blowing device (22) being configured for ejecting a gas flow towards the semi-finished product (50) moving along the advancement direction (A) and for enabling a first fold of at least one transversal end sheet of the semi-finished product (50),

> at least one second guiding element (25) arranged downstream the first guiding element (10) along the advancement direction of the semi-finished product (50), said second guiding element (25) developing along a development direction configured for extending, under an operative condition of the folding device (1 ), parallel to the advancement direction (A) of the semi-finished product (50), said second guiding element (25) comprising at least one descending section (25a) configured for developing towards the second base portion (20) along the advancement direction (A) of the semi-finished product (50), the second guiding element (25) being configured for contacting the transversal end sheet folded by the second lower blowing device (22) for enabling the further fold of said transversal end sheet.

In a 30th aspect according to the preceding aspect, the descending section (25a) of the second guiding element (20) is substantially arranged above the ejection opening (24) of the second lower blowing device (22).

In a 31 st aspect according to the aspect 29 or 30, the descending section (25a) comprises a sloped section, particularly a rectilinear one, defining a predetermined angle with the supporting surface (21 ) of the second base portion 20 less than 70°, particularly less than 45°, still more particularly comprised between 5° and 30°; said angle being comprised between the descending section (25a) of the second guiding element (25) and the supporting surface of the second base portion (4) and facing the ejection opening (24) of the second lower blowing device (22).

In a 32nd aspect according to anyone of the aspects from 29 to 31 , the descending section (25a) of the second guiding element (25) extends between a first end (25b) - facing the ejection opening (8) of the first lower blowing device (6) - and a second end (25c) distanced from and opposite to the first end (25b), the first and second ends (25b, 25c) having a predetermined minimum distance along the development direction of the second guiding element (25) in order to define a length (D7) of the descending section (25a), particularly said length (D7) being greater than 5 mm, still more particularly being comprised between 20 and 300 mm.

In a 33rd aspect according to the preceding aspect, the first and second ends (25b, 25c) of the descending section (25a) of the second guiding device (25) are configured for having a predetermined minimum distance along the gas flow ejection direction from the second lower blowing device (22) in order to define a difference in height (D8) of the descending section (25a), said difference in height being greater than 5 mm, particularly being comprised between 10 and 300 mm, still more particularly being comprised between 10 and 50 mm.

In a 34th aspect according to the aspect 32 or 33, the second guiding element (25) comprises at least one abutment section (25d) connected, optionally unitarily connected, to the first end (25b) of the descending section (25a) and extending along a rectilinear direction opposite to the second end (25c) of the descending section, particularly said abutment section (25d) extends substantially parallel to the supporting surface (21 ) of the second base portion (20).

In a 35th aspect according to the preceding aspect, the abutment section (25d) of the second guiding element (25) has a predetermined minimum distance (D9) from the supporting surface (20) of the second base portion greater than 5 mm, particularly comprised between 10 and 300 mm.

In a 36th aspect according to anyone of the aspects from 32 to 35, the second guiding element (25) comprises at least one pressing section (25f) connected, optionally unitarily connected, to the second end (25c) of the descending section (25a) and extending along a rectilinear direction opposite to the first end (25b) of the descending section (25a), particularly the pressing section (25f) extends substantially parallel to the supporting surface (21 ) of the second base portion (20).

In a 37th aspect according to the preceding aspect, the pressing section (25f) has a predetermined minimum distance (D10) from the supporting surface (21 ) of the second base portion greater than 1 mm, particularly comprised between 1 and 5 mm.

In a 38th aspect per the aspect 36 or 37, the pressing section (25f) of the second guiding element (25) extends parallel to the abutment section (25d) of the second guiding element (25) itself. In a 39th aspect according to anyone of the aspects from 36 to 38, the descending section (25a) of the second guiding element (25) is interposed between the pressing section (25f) and the abutment section (25d) of the second guiding element (25) itself.

In a 40th aspect according to anyone of the aspects from 32 to 39, the ejection opening (24) of the second lower blowing device (22) is interposed between the first and second end portions (20a, 20b) of the second base portion (20), the second end portion (20b) of the base portion (20) facing the second end (25c) of the descending section (25a) of the second guiding element (25),

wherein the second guiding element (25) extends to the second end portion (20b) of the second base portion (20).

In a 41 st aspect according to anyone of the aspects from 32 to 40, the second guiding element (125) extends along a development direction, substantially parallel to the development direction of the second base portion, between a first and second end portions,

the first end portion of the second guiding element being arranged at the ejection opening (24) of the second lower blowing device, while the second end portion of the second guiding element (25) being arranged at the second end portion of the second base portion.

In a 42nd aspect according to anyone of the aspects from 29 to 41 , the folding device (1 ) comprises at least one adjustment member (26) engaged, on one side, with the supporting frame (2) and, on the other side, with the second guiding element (25), said adjustment member (26) being configured for relatively moving the second guiding element (25) with respect to the supporting frame (2) along an adjustment direction (R3) towards or away from the supporting surface (21 ) of the second base portion (20), said adjustment direction (R3) being substantially parallel to one gas ejection direction from the ejection opening (24) of the second lower blowing device (22).

In a 43rd aspect according to anyone of the aspects from 29 to 42, the folding device (1 ) comprises at least one further adjusting member (27) engaged, on one side, with the supporting frame (2) and, on the other side, with the second guiding element (25), said further adjusting member (27) being configured for relatively moving the second guiding element (25) with respect to the supporting frame (2) along an adjustment direction transversal to the development direction of the second base portion (4) and transversal to a gas flow ejection direction from the ejection opening (24) of the second lower blowing device (22).

In an 44th aspect according to anyone of the aspects from 29 to 43, the second lower blowing device (22) comprises a plurality of channels (23), each of them has an ejection opening (24) substantially arranged at the supporting surface (21 ) of the second base portion (20), said second lower blowing device (22) being configured for ejecting a respective gas flow from each ejection opening (24) towards the semi-finished product (50) moving along the advancement direction (A) and for enabling a second fold of at least one transversal end sheet (60) of the semi-finished product (50),

optionally wherein the second lower blowing device (22) comprises a number of channels (23) and of respective ejection openings (24) equal to or comprised between 2 and 10, particularly equal to or comprised between 2 and 6.

In a 45th aspect according to anyone of the aspects from 29 to 44, the ejection opening (8) of the lower blowing device (6) has a minimum distance from the ejection opening (24) of the second lower blowing device (22) comprised between 100 and 10,000 mm, particularly comprised between 300 and 5,000 mm, still more particularly between 300 and 1 ,000 mm.

In a 46th aspect according to anyone of the aspects from 29 to 45, the pressing section (1 Of) of the guiding element (10) extends from the second end (10c) of the descending section (10a) to the second guiding element (25).

In a 47th aspect according to anyone of the aspects from 29 to 46, the second lower blowing device (22) is connectable to the gas supplying unit (102), said second lower blowing device (22) comprising at least one adjusting member (28), particularly a solenoid valve, configured for defining a first operative condition of the second lower blowing device (22) wherein the same ejects the gas flow from the ejection opening (24), said third adjusting member (28) being further configured for defining a second operative condition of the lower blowing device (6) wherein the same prevents the gas flow from being ejected from the ejection opening (8),

wherein said third adjusting member (28) is configured for alternately defining the first and second operative conditions of the second lower blowing device (22) as a function of positions taken by the semi-finished product (50) with respect to the ejection opening (24) of the lower blowing device (24) itself.

In a 48th aspect according to the preceding aspect, the folding device (1 ) comprises:

> at least one second sensor (29) arranged upstream the ejection opening (24) of the second lower blowing device (22) and upstream the guiding element (10) of the upper tool (9) along the advancement direction of the semi-finished product (50), said sensor (29) being configured for emitting a control signal regarding the detection of a semi-finished product moving along the advancement direction (A),

> at least one control unit (13) connected to the second sensor (29) and to the third adjusting member (28), said control unit being configured for:

o receiving the control signal from the second sensor (29),

o determining, as a function of said signal received from the second sensor, the relative position of the semi-finished product (50) with respect to the position of the ejection opening (24) of the second lower blowing device (22),

o commanding, as a function of the position of the semi-finished product with respect to the ejection opening (24) of the second lower blowing device and as a function of an advancement speed of the semi-finished product along the advancement direction (A), the first and second operative conditions of the second lower blowing device (22) according to sequences spaced so that the gas flow ejected at time intervals can enable a first fold of at least one transversal end sheet of the semi-finished product (50). In a 49th aspect according to the preceding aspect, the control unit (13) is configured for determining, as a function of the signal received from the second sensor (29) and as a function of the movement speed of the semi-finished product (50) along the advancement direction (A), a passage condition of at least one transversal end sheet of the semi-finished product (50) above the ejection opening (24) of the second lower blowing device (22), the control unit (13) being configured for defining the first operative condition of the third adjusting member (28) only when the passage condition of at least one transversal end sheet of the semi-finished product (50) above the ejection opening (24) of the second lower blowing device (22) is determined.

In a 50th aspect according to anyone of the aspects from 29 to 49, the upper blowing device (16) of the upper tool (9) defines a first upper blowing device, wherein the folding device (1 ) further comprises a second upper blowing device (30) substantially arranged above the ejection opening of the second lower blowing device (22), particularly the second upper blowing device (30) is aligned with the second lower blowing device (22) along the gas flow ejection direction from this latter,

the second upper blowing device comprising at least one channel (31 ) having an ejection opening (42) interposed between the supporting surface (21 ) of the second base portion (20) and the second guiding element (10), said second upper blowing device (30) being configured for ejecting from the respective ejection opening, a gas flow having a direction substantially parallel to the advancement direction (A) of the semi-finished product (50), and configured for enabling a second fold of the transversal end sheet of the semi-finished product (50) previously folded by the second lower blowing device (22).

In a 51 st aspect according to the preceding aspect, the second upper blowing device (30) is configured for ejecting a gas flow directed towards the descending section (25a) of the second guiding element (25).

In a 52nd aspect according to the aspect 50 or 51 , the second upper blowing device (30) comprises a plurality of channels (31 ), each of them has an ejection opening (32),

said second upper blowing device (30) being configured for ejecting, from each of said ejection openings (32), a respective gas flow having a direction substantially parallel to the advancement direction (A) of the semi-finished product (50) for enabling a second fold of the transversal end sheet of the semi-finished product (50),

optionally, wherein the second upper blowing device (30) comprises a number of channels (31 ) and respective ejection openings (32) equal to or comprised between 2 and 10, particularly equal to or comprised between 2 and 6.

In a 53rd aspect according to anyone of the aspects from 50 to 52, the ejection opening (32) of the second upper blowing device (30) has a minimum distance (D1 1 ) from the supporting surface of the second base portion (20) less than the minimum distance between the abutment section (25d) of the second guiding element (25) and the supporting surface of the second base portion (20), particularly the minimum distance (D1 1 ) between the ejection opening of the second upper blowing device (30) and supporting surface of the base portion (20) is comprised between 1 and 200 mm, still more particularly between 3 and 20 mm. In a 54th aspect according to anyone of the aspects from 50 to 53, the second upper blowing device (30) is connectable to the gas supplying unit (102), said second upper blowing device (30) comprising at least one fourth adjusting member (33), particularly a solenoid valve, configured for defining a first operative condition of the second upper blowing device (30), wherein the same ejects the gas flow from the ejection opening (32), said fourth adjusting member (33) being further configured for defining a second operative condition of the second upper blowing device (30) wherein the same prevents the gas flow from being ejected from the ejection opening (18),

wherein said fourth adjusting member (33) of the second upper blowing device (30) is configured for alternately defining the first and second operative conditions as a function of the positions taken by the semi-finished product (50) with respect to the ejection opening (24) of the second lower blowing device (22).

In a 55th aspect according to the preceding aspect, the control unit (13) is connected to the fourth adjusting member (33) of the upper blowing device (30), said control unit (13) being configured for:

o receiving the control signal from the sensor (29),

o determining, as a function of said signal received from the sensor, the relative position of the semi-finished product (50) with respect to the position of the ejection opening (24) of the second lower blowing device (22),

o commanding, as a function of the position of the semi-finished product with respect to the ejection opening of the second lower blowing device, and as a function of an advancement speed of the semi-finished product along the advancement direction (A), the first and second operative conditions of the upper blowing device (30) according to sequences spaced so that the gas flow ejected at time intervals can enable a second fold of the transversal end sheet of the semi-finished product (50).

In a 56th aspect according to the preceding aspect, the control unit (13) is configured for determining, as a function of the signal received from the sensor and as a function of the movement speed of the semi-finished product (50) along the advancement direction (A), the second operative condition of the adjusting members (26, 33) with respect to the second lower and upper blowing devices (22, 30), particularly the control unit (13) is configured for:

> commanding, as a function of the position of the semi-finished product with respect to the ejection opening of the second lower blowing device, and as a function of an advancement speed of the semi-finished product along the advancement direction (A), the second operative condition of the lower blowing device,

> commanding, as a function of the position of the semi-finished product with respect to the ejection opening of the second lower blowing device, and as a function of an advancement speed of the semi-finished product along the advancement direction (A), the second operative condition of the second upper blowing device, the control unit (13) being configured for commanding the second operative condition of the second upper blowing device (30) after commanding the second operative condition of the second lower blowing device.

In a 57th aspect, it is provided a folding device (100) comprising:

> at least one fixed structure (101 ),

> at least one transporting member (103) engaged with the fixed structure (101 ) and configured for engaging at least one semi-finished product (50) of sheet material and for moving it along an operative path along an advancement direction (A), > at least one folding device (1 ) according to anyone of the preceding aspects, the folding device (1 ) being constrained to the fixed structure (101 ) at the operative path, said folding device being configured for receiving the passing semi-finished product (50) and for enabling to fold at least one transversal end sheet of said semi-finished product (50).

In a 58th aspect according to the preceding aspect, the transporting member (103) comprises:

> a first and second conveyor belts (105, 106) overlapped on each other and extending laterally to the folding device (1 ) along the advancement direction of the semi-finished product (50), said first and second conveyor belts (105, 106) being configured for receiving in between the semi-finished product (50) and moving it along the advancement direction (A),

> a third and fourth conveyor belts (107, 108) overlapped on each other and extending laterally to the folding device (1 ) along the advancement direction of the semi-finished product (50) opposite to the first and second conveyor belts (105, 106), said third and fourth conveyor belts (107, 108) being configured for receiving in between the semi-finished product (50) and moving it along the advancement direction (A),

the folding device (1 ) being interposed between the first and second conveyor belts from a side and the third and fourth conveyor belts from the other side.

In a 59th aspect according to the aspect 57 or 58, the control unit (13) is connected to the transporting member (103), the control unit (13) is configured for commanding and adjusting the movement of said transporting member (103) for controlling a movement speed of the semi-finished product along the advancement direction (A).

In a 60th aspect it is provided a process of folding a semi-finished product (50) of sheet material by a folding device (1 ) according to anyone of the aspects from 1 to 56, the process comprising at least the following steps:

> moving a flat semi-finished product (50) of sheet material along an advancement direction (A), said semi-finished product being of a type comprising at least one central sheet (51 ) and at least one transversal end sheet placed in front of or rearwards the central sheet with respect to advancement direction (A) of the semi-finished product (50),

> ejecting a gas flow towards the flat semi-finished product (50) by the lower blowing device (6) during the movement of said semi-finished product (50) along the advancement direction (A), the step of ejecting the gas flow occurring upon the passage of the transversal end sheet at the ejection opening (8) of said transversal end sheet, said ejecting step enabling a first fold of the transversal end sheet with respect to the central sheet away from the ejection opening (8) of the lower blowing device (6),

> moving the semi-finished product (50) along the advancement direction (A) so that the folded transversal end sheet contacts the descending section (10a) of the guiding element (10) which enables a further fold of said transversal end sheet above the central sheet.

In a 61 st aspect according to the preceding aspect, the step of ejecting a gas flow occurs along a direction transversal, particularly normal, to the flat semi-finished product (50) towards the upper tool (9) of the folding device (1 ).

In a 62nd aspect according to the aspect 60 or 61 , the step of ejecting the gas flow occurs discontinuously at predetermined time intervals so that said gas flow can act substantially on the transversal end sheet of the semi-finished product. In a 63rd aspect according to anyone of the aspects from 60 to 62, the step of moving the semi-finished product along the advancement direction (A) occurs at a speed constantly greater than 20 m/min, particularly comprised between 60 and 250 m/min. In a 64th aspect according to anyone of the aspects from 60 to 63, the process comprises at least one further step of ejecting a gas flow by the upper blowing device (16) simultaneously or immediately after the step of ejecting the gas flow from the lower blowing device (6), the gas flow ejected by the upper blowing device (16) hitting the transversal end sheet folded by the lower blowing device (6) for enabling the further fold of said transversal end sheet.

In a 65th aspect according to the preceding aspect, the gas flow ejected from the upper blowing device (16) has an ejection direction substantially parallel and a sense opposite to the advancement direction (A) of the semi-finished product (50). In a 66th aspect according to anyone of the aspects from 60 to 65, the semifinished product (50) comprises a front transversal end sheet and a rear transversal end sheet opposite to each other with respect to the central sheet of the semi-finished product (50), the step of ejecting the gas flow by the lower blowing device (6) enabling to fold the front transversal end sheet,

wherein the process further comprises the following steps:

> after moving the semi-finished product (50) through the guiding element (10) for folding the front transversal end sheet, moving the semi-finished product itself along the advancement direction (A) exiting said guiding element (10) and entering the second guiding element (25),

> ejecting a gas flow towards the flat semi-finished product (50) by the second lower blowing device (22) during the movement of said semi-finished product (50) along the advancement direction (A), the step of ejecting the gas flow occurring upon the passage of the rear transversal end sheet at the ejection opening (24) of said rear transversal end sheet (60), said ejecting step enabling a first fold of the rear transversal end sheet (60) with respect to the central sheet away from the ejection opening (24) of the second lower blowing device (22), > moving the semi-finished product (50) along the advancement direction (A) so that the folded rear transversal end sheet (60) contacts the descending segment (25a) of the second guiding element (25) which enables the further fold of said rear transversal end sheet above the central sheet (51 ).

In a 67th aspect according to the preceding aspect, the step of ejecting the gas flow from the second lower blowing device (22) occurs along a direction transversal, particularly normal, to the flat semi-finished product (50) towards the second guiding element (25).

In a 68th aspect according to the aspect 66 or 67, the step of ejecting the gas flow from the second lower blowing device (22) occurs discontinuously at predetermined time intervals so that said gas flow can act substantially only on the rear transversal end sheet of the semi-finished product.

In a 69th aspect according to anyone of the aspects from 66 to 68, the step of moving the semi-finished product (50) along the advancement direction (A) occurs at a speed constantly greater than 20 m/min, particularly comprised between 60 and 250 m/min.

In a 70th aspect according to anyone of the aspects from 66 to 69 comprising at least a further step of ejecting a gas flow by the second upper blowing device (30) simultaneously or immediately after the step of ejecting the gas flow from the second lower blowing device (22),

the gas flow ejected by the second upper blowing device (30) hitting the rear transversal end sheet folded by the second lower blowing device (22) for enabling the further fold of said transversal end sheet.

In a 71 st aspect according to the preceding aspect, the gas flow ejected from the second upper blowing device (30) has an ejection direction substantially parallel to and the same sense as the advancement direction (A) of the semi-finished product (50). In a 72nd aspect according to anyone of the aspects from 60 to 71 , the semifinished product comprises:

> a central sheet (51 ) comprising at least one first and one second portions (52, 54) interconnected by a central connecting portion (53), the central sheet (51 ) further comprising at least one first and one second lateral connecting portions (55, 56), the central connecting portion (53) is interposed between the first and second portions (52, 54), the first portion (52) is interposed between the first lateral connecting portion (55) and the central connecting portion (53) while the second portion (54) is interposed between the second lateral connecting portion (56) and the central connecting portion (53), each of said portions (52, 53, 54, 55, 56) comprising at least two opposite longitudinal edges and two opposite end edges, the first and second portions (52, 54), the central connecting portion (53) and said lateral connecting portions (55, 56) are joined along the longitudinal edges and aligned along a single connecting direction, joining the first end edges of said portions (52, 53, 54, 55, 56) of the central sheet defines a first transversal edge of the central sheet (51 ) while joining the second end edges of said portions (52, 53, 54, 55, 56) of the central sheet defines a second transversal edge of the central sheet (51 );

> at least one transversal end sheet (60) unitarily joined to and emerging from the first transversal edge of the central sheet (51 ),

wherein the step of ejecting the gas flow from the lower blowing device (6) enables a first fold of the transversal end sheet (60) with respect to the central sheet.

In a 73rd aspect according to the preceding aspect, the transversal end portion (60) comprises a first and second portions (61 , 62) connected to each other, the first portion (61 ) being interposed between the central sheet (51 ) and second portion (62), the step of ejecting the gas flow from the lower blowing device (6) enables a first fold of the transversal end sheet (60) with respect to the central sheet and a relative fold of the second portion with respect to the first portion, particularly, upon the first fold of the transversal end sheet, the first and second end portions define a substantially "L" cross-section, optionally the first portion (61 ) emerges transversally from the central sheet while the second portion (62) emerges transversally from the first portion (61 ).

In a 74th aspect according to the preceding aspect, the step of ejecting the gas flow from the upper blowing device (16) enables the relative fold between the first and second portions of the transversal end sheet (60).

In a 75th aspect according to anyone of the aspects from 71 to 74, said transversal end sheet (60) defines a front transversal end sheet, the step of folding said front transversal end sheet (60) being folded by the lower blowing device (6) and by the guiding element (10) and optionally by the upper blowing device (16).

In a 76th aspect according to anyone of the aspects from 70 to 75, the transversal end sheet (60) of the semi-finished product comprises a front transversal end sheet (60), the semi-finished product (50) further comprises at least one rear transversal end sheet (70) unitarily joined to and emerging from the second transversal edge of the central sheet (51 ).

wherein the step of ejecting the gas flow from the second lower blowing device (22) enables a first fold of the rear transversal end sheet (70) with respect to the central sheet (51 ).

In a 77th aspect according to the preceding aspect, the rear transversal end portion (70) comprises a first and second portions (71 , 72) connected to each other, the first portion (71 ) being interposed between the central sheet (51 ) and second portion (72), the step of ejecting the gas flow from the second lower blowing device (22) enables a first fold of the rear transversal end sheet (70) with respect to the central sheet and a relative fold of the second portion with respect to the first portion,

particularly, upon the first fold of the transversal end sheet, the first and second portions (71 , 72) define a substantially "L" cross-section, optionally the first portion (71 ) emerges transversally from the central sheet while the second portion (72) emerges transversally from the first portion (71 ).

In a 78th aspect according to the preceding aspect, the step of ejecting the gas flow from the upper blowing device (16) enables the relative fold between the first and second portions of the transversal end sheet (60).

In a 79th aspect according to anyone of the aspects from 75 to 78, the step of folding said rear transversal end sheet (70) being performed by the second lower blowing device (22) and by the second guiding element (25) and optionally by the second upper blowing device (30). BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments and some aspects of the invention will be herein described in the following with reference to the attached drawings given only in an indicative and therefore non-limiting way, wherein:

> Figure 1 is a schematic lateral view of a folding device according to the present invention;

> Figure 1A is a detailed view of the folding device according to the present invention;

> Figure 1 B is a schematic view of an embodiment variant of a folding device according to the present invention;

> Figure 1 C is a detailed view of a folding device according to the present invention;

> Figure 1 D is a lateral schematic view of a folding plant according to the present invention;

> Figure 2 is a front view of a folding plant according to the present invention;

> Figures from 3 to 10 schematically illustrate a first process of folding a sheet semi-finished product by a folding device according to the present invention; > Figures from 1 1 to 18 schematically illustrate a second process of folding a sheet semi-finished product by a folding device according to the present invention;

> Figures from 19 to 26 schematically illustrate a third process of folding a sheet semi-finished product by a folding device according to the present invention; > Figures from 27 to 34 schematically illustrate a fourth process of folding a sheet semi-finished product by a folding device according to the present invention.

DEFINITIONS AND CONVENTIONS

It is observed that in the present detailed description corresponding parts illustrated in the different figures are indicated with the same numeral references. The figures could illustrate the object of the invention by not-to-scale representations; therefore, parts and components illustrated in the figures regarding the object of the invention could only refer to schematic representations.

In the following description and in the claims, the terms "upstream" and "downstream" refer to an advancement direction A of a sheet semi-finished product 50 along an operative path.

The term "semi-finished product 50 means an intermediate product destined to define a finished product upon further processings. The semi-finished product 50 can be made at least partially of a sheet material, particularly a paper sheet material. The term "paper material" means paper or paperboard; particularly, the sheet material useable for making the semi-finished product can have a grammage comprised between 60 and 800 g/m 2 , particularly comprised between 200 and 400 g/m 2 The semi-finished product of paper sheet material of interest extends between a first and second prevalent development surfaces and can, in an embodiment variant thereof, be covered on at least a part of the first and/or second prevalent development surfaces by a coating of plastic material, for example a film. The coating can be used for defining a water and/or moisture barrier useful for avoiding the weakening and the loss of structurality of the semi- finished product. Advantageously but in a non-limiting way, the coating could comprise a plastic film adapted to completely cover both the sides (first and second prevalent development surfaces) of the paper material defining the semifinished product; the thickness of the coating film can have values varying from 5 to 300 pm, particularly from 5 to 200 pm, still more particularly from 8 to 90 pm. The coating plastic material can be for example selected among the following materials: LDPE, HDPE, PP, PE.

The sheet semi-finished product 50 has a thickness - defined by a maximum distance between a first and second prevalent development surfaces of the semifinished product itself - for example less than 10 mm, particularly comprised between 0.1 and 1 mm.

The semi-finished product 50 comprises a central sheet 51 comprising at least one first and one second portions 52, 54 interconnected by a central connecting portion 53. The central portion 51 further comprises at least one first and one second lateral connecting portions 55, 56. As shown in Figure 4 for example, the central connecting portion 53 is interposed between the first and second portions 52, 54, the first portion 52 is interposed between the first lateral connecting portion 55 and central connecting portion 53 while the second portion 54 is interposed between the second lateral connecting portion 56 and the central connecting portion 53. Each of said portions 52, 53, 54, 55, 55 comprises at least two opposite longitudinal edges and two opposite end edges: the portions 52, 54, the central connecting portion 53 and said lateral connecting portions 55, 56 are joined along the longitudinal edges and are aligned along a single connecting direction. Particularly, each of the portions 52, 53, 54, 55, 56 of the central sheet comprises a first and second end edges: joining the first end edges of the portions 52, 53, 54, 55, 56 defines a first transversal edge of the central sheet 51 , while joining the second end edges of the portions 52, 53, 54, 55, 56 defines a second transversal edge of the central sheet 51 .

In a preferred configuration, which does not limit the invention, the first portion 52 of the sheet 51 has a rectangular shape perimetrally delimited by a lower edge, a first and second lateral edges and an upper edge. Analogously, the second portion 54 of the sheet 51 has a rectangular shape perimetrally delimited by a lower edge, a first and second lateral edges and an upper edge. Advantageously, the first and second portions 52, 54 comprise a sheet substantially having the same shape and size.

The central portion 53 and lateral connecting portions 55, 56 have also a rectangular shape; such portions have substantially the same shape and/or size and are unitarily joined to the portions 52 and 54 of the central sheet 51 at the lateral edges.

The semi-finished product 50 further comprises at least one transversal end sheet unitarily joined to the central sheet 51 and emerging from this latter from the firsts and/or second transversal edges of the central sheet 51 . In a preferred but non- limiting embodiment of the semi-finished product 50, the same comprises a transversal end sheet 60 connected to and emerging from the first transversal edge of the central sheet 51 ; particularly, said transversal end sheet 60 is unitarily joined to and emerges from the first portion 52 of the central sheet. Said transversal end sheet 60 has, in a non-limiting way, a substantially rectangular shape. The sheet 60 can comprise a single portion has illustrated in Figure 4 for example, or can comprise a first and second portions 61 , 62 unitarily joined to each other and unitarily joined to the central sheet. The sheet 60 is unitarily joined to the central sheet 51 only by the second portion 62 which is interposed between the first portion of the sheet 60 and the central sheet.

In a preferred but non-limiting embodiment of the semi-finished product 50, the transversal end sheet 60 defines a front transversal end sheet; the semi-finished product can further comprise a rear transversal end sheet 70 connected, particularly unitarily joined to the central sheet 51 opposite to the end sheet 60. Particularly, the transversal end sheet 70 is unitarily joined to the second transversal edge of the central sheet 51 and optionally emerges from the second portion 52. The sheet 70 can have the same shape as the shape of the central sheet. The attached figures illustrate a sheet 70 having in a non-limiting way a rectangular shape identical to the sheet 60.

The rear transversal end sheet 70 can comprise a single portion as illustrated in Figure 4 for example, or can comprise a first and second portions 71 , 72 unitarily joined to each other and unitarily joined to the central sheet. The sheet 70 is unitarily joined to the central sheet 51 only by the second portion 72 which is interposed between the first portion 71 of the sheet 70 and the central sheet 51 .

DETAILED DESCRIPTION

Folding device

1 generally indicates a folding device particularly for flat semi-finished products of sheet material, optionally of paper material, for example destined to form containers for drugs, cosmetic and food products. The folding device 1 comprises at least one supporting frame 2 associable to a fixed structure 101 of a folding plant 100 which, as it will be better described in the following, is configured for moving the semi-finished product 50 along the advancement direction A.

As it is visible in Figure 1 for example, the folding device 1 can comprise a lower tool 3 which comprises at least one base portion 4 extending along a longitudinal direction between a first and second end portions 4a, 4b; the base portion 4 has a supporting surface 5 configured for receiving and supporting the moving semifinished product 50. Particularly, the base portion can comprise a plate configured for extending, under an operative condition of the folding device 1 , parallel to the advancement direction A of the semi-finished product 50. Advantageously, but in a non-limiting way, the base portion extends along a rectilinear development direction which, under operative conditions of the folding device 1 , is substantially horizontal. The supporting surface 5 develops along a plane which, under operative conditions of the device 1 , is horizontal.

In a preferred but non-limiting embodiment of the invention, the base portion 4 comprises a bar of metal material, for example, having a rectangular cross-section with a length, measured along the longitudinal development direction and under operative conditions of the device 1 , measured along the advancement direction of the semi-finished product, comprised between 50 mm and 3,000 mm, particularly between 50 and 1 ,000 mm. De facto, the length of the base portion 4 is defined by the maximum distance between the first and second end portions 4a, 4b of the base portion 4 itself. Moreover, the bar has a width, measured normal to the development direction of the base portion 4 itself and parallel to the plane of the supporting surface, comprised between 1 mm and 50 mm, particularly comprised between 5 and 15 mm. Specifically, the supporting surface 5 has the same width as the width of the base portion 4; the supporting surface 5 is configured for having a width less than the width of the semi-finished product 50 moving on the base portion 4.

As it is visible in the attached figures, the lower tool further comprises at least one lower blowing device 6 comprising at least one channel 7 having an ejection opening 8 substantially arranged at the supporting surface 5 of the base portion; the ejection opening is substantially arranged on the same extension plane of the supporting surface 5. The attached figures illustrate a preferred but non-limiting configuration of the invention, wherein the ejection opening 8 is arranged slightly below the supporting surface 5 of the base portion, according to an operative condition of the folding device 1 .

More particularly, the lower blowing device 6 is associated to the base portion 4 and is engaged between the first and second end portions 4a, 4b. The lower blowing device 6 comprises substantially a main body on which a channel 7 is made, and an associated ejection opening 8. The channel 7 is associable by suitable channels to the supplying unit 102 (see the channel a' in Figures 1 , 1 B and 1 D, for example) which is configured for supplying pressurized gas to the lower blowing device 6. The lower blowing device 6 is configured for ejecting a gas flow towards the semi-finished product 50 moving along the advancement direction A and for enabling a first fold of at least one transversal end sheet of the semi-finished product 50.

The lower blowing device 6 can comprise a plurality of channels 7, each of them has an ejection opening 8 disposed substantially at the supporting surface 5 of the base portion 4. Said lower blowing device 6 is configured for ejecting a respective gas flow from each ejection opening 8 towards the semi-finished product 50 moving along the advancement direction A and for enabling a first fold of at least one longitudinal end sheet of the semi-finished product 50. Optionally, the lower blowing device 6 comprises a number of channels 7 and respective ejection openings 8 equal to or comprised between 1 and 10, particularly equal to or comprised between 2 and 5.

In a preferred but non-limiting embodiment of the invention, the lower blowing device 6 comprises at least one flow adjusting member 1 1 , for example a solenoid valve, configured for defining a first operating condition of the lower blowing device 6 wherein the same ejects the gas flow from the ejection opening; the flow adjusting member 1 1 is further configured for defining a second operative condition of the lower blowing device 6 wherein the same prevents the gas flow from being emitted from the ejection opening 8. In a preferred but non-limiting embodiment of the invention, the adjusting member 1 1 is configured for alternately defining the first and second operative conditions as a function of positions taken by the semi-finished product 50 with respect to the ejection opening 8. De facto, the adjusting member 1 1 enables to emit discontinuously gas flows and particularly at predetermined time intervals defined, for example, as a function of the moving speed of the semi-finished product 50 along the advancement direction A.

Advantageously but in a non-limiting way, the folding device 1 comprises at least one sensor 12, for example a position sensor or a photocell disposed upstream the ejection opening 8 of the lower blowing device 6 along the advancement direction of the semi-finished product 50. The attached figures illustrate in a non- limiting way a configuration of the sensor 12 disposed above the base portion 4 so that the sensor 12 faces the supporting surface 5 of the semi-finished product 50 (see Figures 1 , 1 B, 3 and 5, for example). However, it is not excluded the possibility of associating the sensor 12 to the base portion 4 and/or to the lower blowing device 6 so that the sensor itself is positioned, under an operative condition of the folding device 1 , below the supporting surface 5.

The sensor 12 is configured for emitting a control signal regarding the detection of a semi-finished product 50 moving along the advancement direction A. Further, the folding device 1 can comprise a control unit 13 connected to the sensor 12 and to the adjusting member 1 1 (see the respective connecting lines f and a shown in Figure 1 , for example). The control unit 13 can further be connected to the supplying unit 102 and is configured for commanding for example an activation of the same (see the connecting line s shown in Figure 1 , for example). The control unit 13 is configured for:

o receiving the control signal from the sensor 12,

o determining, as a function of said signal received from the sensor 12, the relative position of the semi-finished product 50 with respect to the position of the ejection opening 8 (advantageously the position can be determined as a function of the signal received from the sensor 12 and as a function of an advancement speed of the semi-finished product 50 along the advancement direction A which can be determined by an encoder, for example),

o commanding, as a function of the position of the semi-finished product with respect to the ejection opening 8, and as a function of a moving speed of the semi-finished product along the advancement direction A (the speed can be determined by an encoder, for example), the first and second operative conditions of the lower blowing device 6 according to sequences spaced so that the gas flow ejected at time intervals can enable a first fold of at least one transversal end sheet of the semi-finished product 50.

More particularly, the control unit 133 is configured for determining, as a function of the signal received from the sensor and as a function of the moving speed of the semi-finished product 50 along the advancement direction A, a passage condition of at least one transversal end sheet of the semi-finished product 50 above the ejection opening 8. The control unit 13 is configured for defining the first operative condition of the adjusting member 1 1 only after determining the passage condition of at least one transversal end sheet of the semi-finished product 50 above the ejection opening 8. Advantageously, the control unit 13 is configured for commanding the second operative condition of the adjusting member 1 1 in the condition wherein the same determines the transversal end sheet is not located above the ejection opening 8.

As it is visible in the attached figures, further the folding device 1 comprises an upper tool 9 substantially facing the lower tool 3 according to the ejection direction of the gases of the lower tool 6. The upper tool 9 comprises at least one guiding element 10 developing along a development direction configured for extending, under an operative condition of the folding device 1 , parallel to the advancement direction A of the semi-finished product 50. The guiding element 10 comprises at least one descending section 10a configured for developing towards the lower tool 3 along the advancement direction A of the semi-finished product 50: the guiding element 10 is configured for contacting the transversal end sheet folded by the lower blowing device 6 for enabling the further fold of the transversal end sheet.

As it will be better described in the following, the guiding element 10 is substantially a type of hindrance for the end sheet folded by the lower blowing device 6 which enables to intercept only this latter sheet of the semi-finished product for enabling the further fold above the central sheet 51 .

More particularly, the descending section 10a of the guiding element 10 is configured for being disposed immediately downstream the ejection opening 8 of the lower blowing device 6 along the advancement direction A of the semi-finished product 50 (see Figure 1 ). Optionally, the descending section 10a and ejection opening 8 are disposed at a predetermined minimum distance D1 from each other along the development direction of the guiding element 10 (Figure 1A), particularly wherein said minimum distance D1 is less than 500 mm, still more particularly is comprised between 5 mm and 150 mm.

The descending section 10a comprises a sloped section, particularly a rectilinear one, defining a predetermined angle with the supporting surface 5 less than 70°, particularly less than 45°, still more particularly comprised between 5° and 30°; the angle is subtended between the descending section 10a and supporting surface 5 and faces the ejection opening 8 of the lower blowing device 6. The descending section 10a extends between a first end 10b - facing the ejection opening 8 of the lower blowing device 6 - and a second end 10c spaced and opposite to the first end 10b; the first and second ends 10b, 10c have a predetermined minimum distance along the development direction of the guiding element 10 for defining a length D3 (Figure 1A) of the descending section 10a, particularly said length D3 being greater than 5 mm, still more particularly being comprised between 20 mm and 300 mm. The first and second ends 10b, 10c of the descending section 10a are configured for having a predetermined minimum distance along the ejection direction of the gas flow from the lower blowing device 6 for defining a difference in height D2 of the descending section 10a (Figure 1 ); the difference in height being greater than 5 mm, particularly being comprised between 10 and 300 mm, still more particularly being comprised between 10 and 50 mm.

As it is visible in Figure 1A for example, the guiding element 10 can comprise at least one abutment section 10d connected, optionally unitarily joined, to the first end 10b of the descending section 10a and extending along a rectilinear direction opposite to the second end 10c of the descending section 10a. The abutment section 10d extends substantially parallel to the supporting surface 5 of the base portion 4 of the lower tool 3. The abutment section 10d has a predetermined minimum distance D4 from the supporting surface 5 of the upper base portion equal to 5 mm, particularly comprised between 10 and 300 mm. As it is visible in Figures 1 , 1A and 1 B for example, the guiding element 10 can further comprise at least one pressing section 10f connected, optionally unitarily joined, to the second end 10c of the descending section 10a and extending along a rectilinear direction opposite to the first end 10b of the descending section 10a. As it is visible in Figure 1 for example, the pressing section 10f extends opposite to the abutment section so that the descending section 10a is interposed between the pressing section 10f and abutment section 10d. The pressing section 10f extends substantially parallel to the supporting surface 5 of the base portion 4 of the lower tool 3 and particularly parallel to the abutment section 10d. The pressing section 10f has a predetermined minimum distance D5 from the supporting surface 5 of the base portion 4 greater than 1 mm, particularly comprised between 1 and 5 mm. More particularly, the second end portion 4b of the base portion 4 faces the second end 10c of the descending section 10a of the guiding element 10, while the abutment section faces the first end portion 10a of the base portion 4; advantageously but in a non-limiting way, the guiding element 10 extends to the second end portion 4b of the base portion 4, particularly, the pressing portion extends above the base portion 4 from a midline portion of the base portion to the second end portion of the base portion 4 itself.

In other words, the guiding element 10 extends along a development direction, substantially parallel to the development direction of the base portion 4, between a first and second end portions. The first end portion of the guiding element is disposed at the ejection opening 8 of the lower blowing device 6, while the second end portion of the guiding element 10 is disposed at the second end portion 4b of the base portion 4.

From the structural point of view, the guiding element can comprise, as illustrated in the attached figures, a plate for example of metal material in a single piece. In a preferred but non-limiting embodiment of the invention, the descending section 10a and the abutment section 10d of the guiding element 10 are unitarily joined while the pressing section 10f comprises a separate body; advantageously, the pressing section 10f is constrained to the descending section or abutment section by an adjusting member 34 configured for enabling to relatively displace between said pressing section and descending section 10a along a direction substantially parallel to the development direction of the guiding element itself and/or along a direction substantially parallel to the direction of the gas ejected from the lower blowing device 6. Advantageously, as illustrated in Figure 1 for example, also the adjusting member 34 can be connected to the control unit 13 (see the connecting line g shown in Figure 1 for example) which can be configured for commanding the adjustment of the position of the pressing section 10f by the control member 34.

As it is visible in Figures 1 , 1 B and 1 D for example, the folding device 1 can comprise at least one adjusting member 14 engaged, on one side, to the supporting frame 2 and, on the other side, to the guiding element 10; said adjusting member 14 being configured for relatively moving the guiding element 10 with respect to the supporting frame 2 along an adjustment direction R1 (Figure 1 ) towards or away from the supporting surface 5 of the base portion 4. The adjusting direction R1 is substantially parallel to a direction of the gas ejected from the ejection opening 8; the adjusting member 14 is configured for enabling to adjust the distance between the guiding element 10 and supporting surface 5 of the base portion 4. Particularly, the adjusting member 14 can comprise, for example: a slide movable along a guide the position thereof being adjustable by pushing a screw, a slide, a ring nut, a chain, a belt. Advantageously, as illustrated in Figure 1 for example, also the adjusting member 14 can be connected to the control unit 3 (see the connecting line c shown in Figure 1 , for example) which can be configured for commanding the adjustment of the guiding element 10 by the control member 14.

As it is visible in Figures 1 , 1 B, 1 D and 2 for example, the folding device 1 can further comprise at least one further adjusting member 15 engaged, on one side, with the supporting frame 2 and, on the other side, with the guiding element 10. Said further adjusting member 15 is configured for relatively moving the guiding element 10 with respect to the supporting frame 2 along an adjusting direction R2 (Figure 2) transversal to the development direction of the base portion 4 and transversal to a direction of the gas flow ejected from the ejection opening 8. Specifically, the further adjusting member 15 can comprise for example: a worm, slide, ring nut, chain, belt. Advantageously, as illustrated in Figure 1 for example, also the further adjusting member 15 can be connected to the control unit 13 (see the connecting line d shown in Figure 1 for example) which can be configured for commanding the adjustment of the guiding element 10 by controlling the further member 15.

As hereinbefore described, the semi-finished product 50 can comprise at least one transversal end sheet having a single sheet 60 (see Figure 4, for example); under such condition, the lower blowing device 6, when said sheet moves, is configured for ejecting a gas flow adapted to raise said sheet 60 with respect to the central sheet 51 (Figures 5 and 6). The guiding element 10 is disposed at a predetermined distance from the supporting surface 5 in order to prevent the single end sheet 60 from contacting the abutment section 10d; upon the advancement of the semi-finished product along the direction A, the end sheet 60 contacts the descending section 10a which enables the further fold of the sheet 60.

As it is visible in Figure 12 for example, the semi-finished product 50 can have a transversal end sheet 60 comprising a first and second portions 61 , 62. Under such condition, the lower blowing device 6, when said sheet moves, is configured for ejecting a gas flow adapted to raise the first and second portions 61 and 62 of sheet 60 with respect to the central sheet 51 (Figures 13 and 14). The guiding element 10 is disposed at a predetermined distance from the supporting surface 5 in order to prevent the first portion from contacting the abutment section 10d enabling at the same time to fold the second portion 62 with respect to the first portion as illustrated in Figure 13; following the advancement of the semi-finished product 50 along the direction A, the end sheet 60 contacts the descending section 10a which enables the further fold of the sheet 60. Following the passage of the sheet 60 from the descending section 10a, the first and second portions are completely folded above the central sheet as schematically illustrated in Figure 17.

As it is visible in the attached figures, the lower tool 9 can comprise - in a non- limiting way - an upper blowing device 16 above the lower blowing device 6 and at the guiding element 10. The upper blowing device 16 comprises at least one channel 17 having an ejection opening 18 which is substantially interposed between the supporting surface 5 of the base portion 4 and guiding element 10. As it is visible in Figure 1A, the ejection opening 18 of the upper blowing device 16 has a minimum distance D6 from the supporting surface 5 of the base portion 4 less than the minimum distance between the abutment section 10d of the guiding element 10 and the supporting surface of the base portion 4. The minimum distance D6 between the ejection opening of the upper blowing device 16 and supporting surface 5 of the base portion 4 is comprised between 1 and 200 mm, still more particularly between 3 and 20 mm.

Further, the ejection opening 18 is interposed - along a direction parallel to the direction of the gas ejected from the lower blowing device - between the abutment section 10d of the guiding element 10 and supporting surface 5. The opening 18 is further interposed - along a direction parallel to the advancement direction A of the semi-finished product 50 - between the ejection opening 8 of the lower blowing device 6 and descending section 10a.

More specifically, the upper blowing device 16 is configured for emitting from the respective ejection opening 18 a gas flow having a direction substantially parallel to the advancement direction A of the semi-finished product 50 and configured for enabling a second fold of the transversal end sheet of the semi-finished product 50 previously folded by the lower blowing device 6. Particularly and as it is visible for example in Figure 1A, the lower blowing device 16 is configured for ejecting a gas flow towards the ejection opening 8 of the lower blowing device 6, in other words opposite to the guiding element 10.

As hereinbefore described, the lower blowing device 6 enables a first fold of the transversal end sheet as illustrated in Figures 5 and 6 for example; particularly, the device 6 enables to raise the transversal end sheet with respect to the central sheet 51 towards the upper blowing device 16 and towards the guiding element 10. The upper blowing device 16 is configured for ejecting a flow adapted to hit the transversal end sheet previously folded (raised) by the device 6, in order to further fold the sheet as illustrated in Figure 7 for example: in this way, the upper blowing device 16 enables to correctly promote the insertion of the transversal end sheet below the guiding element 10. The upper blowing device 16 can advantageously comprise a plurality of channels 17 each of them has an ejection opening 18; the upper blowing device 16 is configured for emitting, from each of said ejection openings 18, a respective gas flow having a direction substantially parallel to the advancement direction A of the semi-finished product 50 for enabling a second fold of the transversal end sheet of the semi-finished product 50. Optionally, the upper blowing device 16 comprises a number of channels 17 and respective ejection openings 18 equal to or comprised between 2 and 10, particularly equal to or comprised between 2 and 6. As schematically shown in Figure 1 , the upper blowing device 16 is connectable to the supplying unit 102 (see the connecting line b' shown in Figure 1 , for example). The upper blowing device 16 comprises at least one flow adjusting member 19, particularly a solenoid valve, configured for defining a first operative condition of the upper blowing device 16 wherein the same ejects the gas flow from the ejection opening 18; the flow adjusting member 19 is further configured for defining a second operative condition of the upper blowing device 16 wherein the same prevents the gas flow from being ejected from the ejection opening 18. The flow adjusting device 19 of the upper blowing device 16 is configured for alternately defining the first and second operative conditions as a function of the positions taken by the semi-finished product 50 with respect to the ejection opening 8 of the lower blowing device 6.

Advantageously, the flow adjusting member 19 is connected to the control unit 13 (see the connecting line b in Figure 1 ) which is configured for:

> receiving the control signal from the sensor 12,

o determining, as a function of said signal received from the sensor, the relative position of the semi-finished product 50 with respect to the position of the ejection opening 8 of the lower blowing device 6 (advantageously the position can be determined as a function of the signal received from the sensor 12, and as a function of an advancement speed of the semi-finished product 50 along the advancement direction A which can be determined by an encoder, for example),

o commanding, as a function of the position of the semi-finished product with respect to the ejection opening of the lower blowing device, and as a function of a moving speed of the semi-finished product along the advancement direction A (the speed can be determined by an encoder, for example), the first and second operative conditions of the upper blowing device 16 according to sequences spaced so that the gas flow ejected at time intervals can enable a second fold of the transversal end sheet of the semi-finished product 50.

More particularly, the control unit 13 is configured for determining, as a function of a signal received from the sensor 12, and as a function of the moving speed of the semi-finished product 50 along the advancement direction A, the second operative condition of the lower and upper blowing devices 6, 16; particularly, the control unit 13 is configured for:

> commanding, as a function of the position of the semi-finished product with respect to the ejection opening of the lower blowing device, and as a function of an advancement speed of the semi-finished product along the advancement direction A the second operative condition of the lower blowing device 6,

> commanding, as a function of the position of the semi-finished product with respect to the ejection opening of the lower blowing device, and as a function of an advancement speed of the semi-finished product along the advancement direction A, the second operative condition of the upper blowing device, the control unit 13 is configured for commanding the second operative condition of the upper blowing device 16 after commanding the second operative condition of the flow adjusting member 1 1 of the lower blowing device.

As hereinbefore described, commanding at time intervals the lower and upper blowing devices can be done as a function of the position of the semi-finished product 50 with respect to the opening 8. As an alternative, the control unit 13 can command the second operative condition of the upper blowing device 16 as a function of the position and moving speed of the semi-finished product with respect to the opening 18.

As hereinbefore described, commanding the second operative condition (blowing condition) of the device 16 can be done at time intervals so that the gas ejection is discontinuous and is performed only during predetermined time intervals. However, it is not excluded the possibility of defining a condition of the upper blowing device 16 wherein the same continuously ejects a gas flow during the passage of semi-finished products 50.

As hereinbefore described, the semi-finished product 50 can comprise at least one transversal end sheet having a single sheet 60 (see Figure 4, for example). The upper blowing device 16 is adapted to eject a gas flow along a direction opposite to the advancement direction of the semi-finished product 50; under such condition during the passage of the single sheet 60 from the lower blowing device, this is raised (Figure 5): before the single sheet 60 reaches the descending section 10a, the blowing device ejects a gas flow adapted to further fold the single sheet in order to insert the same inside the descending section 10a (Figure 7). As it is visible in Figure 12, for example, the semi-finished product 50 can have a transversal end sheet 60 comprising a first and second portions 61 , 62. Under such condition, during the passage of the sheet 60 from the lower blowing device, the first and second portions are raised as hereinbefore described and illustrated in Figure 13: before the sheet 60 reaches the descending section 10a, the upper blowing device 16 is configured for emitting a gas flow against the sheet adapted to further fold the first portion 61 with respect to the central sheet 51 , and the second portion 62 with respect to the first portion 62 in order to enable to insert the sheet 60 itself inside the descending section 10a (Figure 15).

According to the position of the upper blowing device 16 (adapted to eject a gas flow along a direction opposite to the advancement direction of the semi-finished product 50), the same is adapted to enable to fold a front transversal end sheet of the semi-finished product 50 considered with reference to the advancement direction A of the semi-finished product 50 itself (see Figures 3-10 and 1 1 -18).

Figure 1 illustrates an embodiment of the folding device 1 , wherein the lower tool 3 comprises a single base portion 4 and a single lower blowing device 6. Figure 1 B rather illustrates an embodiment variant of the folding device 1 wherein the base portion 4 and lower blowing device 6 define respectively a first base portion 4 and a first blowing device 6; the folding device 1 in Figure 1 B comprises, in a non-limiting way, a second base portion 20 disposed downstream the base portion 4 (first base portion) along the advancement direction A of the semifinished product 50. Advantageously but in a non-limiting way, the second base portion 20 comprises a body distinct from the portion 4 and substantially has the same shape and size as the first base portion 4.

Particularly, the second base portion 20 extends along a longitudinal direction between a first and second end portions 20a, 20b. The first end portion 20a of the portion 20 is in proximity of and faces the second end portion 4b of the base portion 4 (Figure 1 B).

The base portion 20 has a supporting surface 21 configured for receiving the moving semi-finished product 50 and supporting it. Particularly, the second base portion 20 can comprise a plate configured for extending, under an operative condition of the folding device 1 , parallel to the advancement direction A of the semi-finished product 50. Advantageously but in a non-limiting way, the base portion 20 extends along a rectilinear development direction which, under an operative condition of the folding device 1 , is substantially horizontal. Advantageously but in a non-limiting way, the second base portion 20 extends parallel to the first base portion 4 and is aligned with this latter along the advancement direction A of the semi-finished product 50.

The supporting surface 21 develops along a plane which, under operative conditions of the device 1 , is horizontal, particularly parallel and at the same height as the supporting surface 5.

In a preferred but non-limiting embodiment of the invention, the base portion 20 comprises a bar, for example of metal material, having a rectangular cross-section having a length, measured along the longitudinal development direction and, under operative conditions of the device 1 , measured along the advancement direction A of the semi-finished product 50, comprised between 50 and 3,000 mm, particularly between 50 and 1 ,000 mm. De facto, the length of the second base portion 20 is defined by the maximum distance between the first and second end portions 20a, 20b of the portion 20 itself. Further, the bar has a width, measured normal to the development direction of the second base portion 20 itself and parallel to the plane of the supporting surface 21 , comprised between 1 and 50 mm, particularly comprised between 5 and 15 mm. specifically, the supporting surface 21 has a width equal to the width of the base portion 20; the supporting surface 5 is configured for having a width less than the width of the semi-finished product 50 moving on the base portion 20.

The attached figures illustrate a configuration of the first and second base portions 4, 20 distinct and distanced from each other at least along the advancement direction A of the semi-finished product 50; however, it is not excluded the possibility of making the first and second portions 4, 20 so that they are unitarily joined to each other.

Referring again to the embodiment in Figure 1 B, as hereinbefore described, the lower tool 3 comprises a lower blowing device 6. In the embodiment in Figure 1 B, said lower blowing device 6 defines a first blowing device 6; the lower tool 3 of the folding device 1 can further comprise at least a second lower blowing device 22 disposed downstream the first lower blowing device 6 along the advancement direction of the semi-finished product 50. Also, the second lower blowing device 22 is connected to the supplying unit 102 illustrated in Figure 1 D; the supplying unit 102 is configured for supplying a pressurized gas to the lower blowing device 22 (see the connecting line c' shown in Figure 1 D).

The second lower blowing device 22 comprises at least one channel 23 having an ejection opening 24 disposed substantially at the supporting surface 21 of the second base portion 20; the ejection opening 24 is substantially disposed on the same extension plane of the supporting surface 21 . The attached figures illustrate a preferred but non-limiting configuration of the invention wherein the ejection opening 24 is disposed slightly below the supporting surface 21 of the second base portion 20, according to an operative condition of the folding device 1 .

More particularly, the second lower blowing device 22 is associated to the second base portion 20 and is engaged by interposition between the first and second end portions 2a, 20b. The second lower blowing device 22 comprises substantially a main body on which at least one channel 23 and an associated ejection opening are provided. The channel 23 is associable by suitable channels to the supplying unit 102 (lines c' in Figure 1 D) which is configured for supplying a pressurized gas to the second lower blowing device 6. The device 22 is configured for ejecting a gas flow towards the semi-finished product 50 moving along the advancement direction A and for enabling a first fold of at least one transversal end sheet of the semi-finished product 50.

As it will be better described in the following, the first lower blowing device 6 can be used for defining a first fold of the front transversal end sheet 60 of the semifinished product 50 while the second lower blowing device 22 can be used for defining a first fold of the rear transversal end sheet 70 of the semi-finished product 50. Figure 1 B illustrates in a non-limiting way a configuration of the folding device 1 wherein the first blowing device 6 is disposed upstream the second lower blowing device 22 along the advancement direction of the semifinished product 50; however, it is not excluded the possibility of implementing a folding device 1 provided with a second blowing device 22 disposed upstream the first blowing device 6 along the advancement direction A of the semi-finished product 50. The second lower blowing device 22 can comprise a plurality of channels 23, each them has an ejection opening 24 disposed substantially at the supporting surface 21 of the second base portion 20. The second lower blowing device 22 is configured for ejecting a respective gas flow from each ejection opening 24 towards the semi-finished product 50 moving along the advancement direction A and for enabling a first fold of at least one transversal end sheet, particularly the rear transversal end sheet 70, of the semi-finished product 50. Optionally, the lower blowing device 22 comprises a number of channels 23 and respective ejection openings 24 equal to or comprised between 2 and 10, particularly equal to or comprised between 2 and 6.

In a preferred but non-limiting embodiment of the invention, the second lower blowing device 22 comprises at least one flow adjusting member 28, for example a solenoid valve, configured for defining a first operative condition of the second lower blowing device 22, wherein the same ejects the gas flow from the ejection opening 24; moreover the flow adjusting member 28 is configured for defining a second operative condition of the lower blowing device 22 wherein the same prevents the gas flow from being ejected from the ejection opening 24. In a preferred but non-limiting embodiment of the invention, the flow adjusting member 28 is configured for alternately defining the first and second operative conditions as a function of positions taken by the semi-finished product 50 with respect to the ejection opening 24. De facto, the adjusting member 28 enables to eject gas flows discontinuously and particularly at predetermined time intervals defined for example as a function of the moving speed of the semi-finished product 50 along the advancement direction A.

Advantageously but in a non-limiting way, the folding device 1 comprises at least one sensor 29, for example a position sensor or photocell, disposed upstream the ejection opening 24 of the second lower blowing device 22 along the advancement direction of the semi-finished product 50, particularly downstream the ejection opening 8 of the device 6. The attached figures illustrate in a non- limiting way a configuration of the sensor 29 disposed above the second base portion 20 so that sensor 29 faces the supporting surface 21 of the semi-finished product 50 (see Figure 1 B for example). However, it is not excluded the possibility of associating the sensor 29 to the second base portion 20 and/or second lower blowing device 22 so that the sensor itself is, under an operative condition of the folding device 1 , below the supporting surface 21 .

The sensor 29 is configured for emitting a control signal regarding the detection of a semi-finished product 50 moving along the advancement direction A. Moreover, the control unit 13 can be connected to the sensor 29 (see the connecting line p for example shown in Figure 1 D) and to the adjusting member 28 (see the connecting h shown in Figure 1 D for example); the control unit 13 is configured for:

o receiving the control signal from the sensor 29,

o determining, as a function of said signal received from the sensor 29, the position regarding the semi-finished product 50 with respect to the position of the ejection opening 24 of the second lower blowing device 22,

o commanding, as a function of the position of the semi-finished product with respect to the ejection opening 24 and as a function of a moving speed of the semi-finished product along the advancement direction A, the first and second operative conditions of the second lower blowing device 22 according to sequences spaced so that the gas flow ejected at time intervals can enable a first fold of at least one transversal end sheet, particularly of the rear transversal end sheet 70, of the semi-finished product 50.

More particularly, the control unit 13 is configured for determining, as a function of the signal received from the sensor 29 and as a function of the moving speed of the semi-finished product 50 along the advancement direction A, a passage condition of at least one transversal end sheet of the semi-finished product 50 above the ejection opening 24. The control unit 13 is configured for defining the first operative condition of the adjusting member 28 only after determining the passage condition of at least one transversal end sheet of the semi-finished product 50 above the ejection opening 24. Advantageously, the control unit 13 is configured for commanding the second operative condition of the adjusting member 28 under the condition wherein the same determines the transversal end sheet is not disposed above the ejection opening 24.

As it is visible in Figure 1 B for example, the guiding element 10 can define a first guiding element 10; the upper tool 9 can further comprise at least one second guiding element 25 disposed downstream the first guiding element 10 along the advancement direction of the semi-finished product 50. The second guiding element 25 extends along a development direction which, under an operative condition of the folding device 1 , is parallel to the advancement direction A of the semi-finished product 50. Particularly, the second guiding element 25 extends parallel to the guiding element 10; the first and second guiding elements 10, 25 are distinct from each other and are disposed at a minimum distance from each other comprised between 10 and 5,000 mm, particularly between 200 and 1 ,000 mm.

The second guiding element 25 comprises at least one descending section 25a configured for developing towards the supporting surface 21 of the second portion 20 along the advancement direction A of the semi-finished product 50: the guiding element 25 is configured for contacting the transversal end sheet folded by the second lower blowing device 22 for enabling the further fold of said transversal end sheet.

As it will be better described in the following, the guiding element 25 is substantially a type of hindrance to the end sheet folded by the second lower blowing device 22 which enables to intercept only this latter sheet of the semifinished product for enabling the further fold above the central sheet 51 .

The descending section 25a of the second guiding element 25 is substantially disposed above the ejection opening 24 of the second lower blowing device 22. The descending section 25a comprises a sloped section, particularly a rectilinear one, defining a predetermined angle with the supporting surface 21 less than 70°, particularly less than 45°, still more particularly comprised between 5 and 30°; the angle is subtended between the descending section 25a and supporting surface 21 and faces the ejection opening 25 of the second lower blowing device 22. The descending section 25a of the second guiding element 25 extends between a first end 25b - facing the ejection opening 8 of the first lower blowing device 6 - and a second end 25c spaced and opposite to the first end 25b; the first and second ends 25b, 25c have a predetermined minimum distance along the development direction of the second guiding element 25 in order to define a length D7 (Figure 1 C) of the descending section 25a; particularly, said length D7 is greater than 5 mm, still more particularly is comprised between 20 and 300 mm. The first and second ends 25b, 25c of the descending section 25a are configured for having a predetermined minimum distance along the direction of the gas flow ejected from the second lower ejection device 22 in order to define a difference in height D8 of the descending section 25a (Figure 1 C); the difference in height is greater than 5 mm, particularly is comprised between 10 and 300 mm, still more particularly is comprised between 10 and 50 mm.

As it is visible in Figure 1 C for example, the guiding element 25 can comprise at least one abutment section 25d connected, optionally unitarily joined, to the first end 25b of the descending section 25a and extending along a rectilinear direction opposite to the second end 25c of the descending section 25a. The abutment section 25d substantially extends parallel to the supporting surface 21 of the second base portion 20 of the lower tool 3. The abutment section 25d has a predetermined minimum distance D9 from the supporting surface 21 of the second base portion 20 greater than 5 mm, particularly comprised between 10 and 300 mm.

As it is visible in Figure 1 C for example, the second guiding element 25 can further comprise at least one pressing section 25f connected, optionally unitarily joined, to the second end 25c of the descending section 25a and extending along a rectilinear direction opposite to the first end 25b of the descending section 25a. As it is visible in Figure 1 C for example, the pressing section 25f extends opposite to the abutment section 25d so that the descending section 25a is interposed between the pressing section 25f and abutment section 25d. The pressing section 25f extends substantially parallel to the supporting surface 21 of the second base portion 20 of the lower tool 3 and particularly parallel to the abutment section 25d. The pressing section 25f has a predetermined minimum distance D10 from the supporting surface 21 of the base portion 20 equal to or greater than 1 mm, particularly comprised between 1 and 5 mm. More particularly, the second end portion 20b of the base portion 20 faces the second end 25c of the descending section 25a of the second guiding element 25, while the abutment section 25d faces the first end portion 20a of the second base portion 20; advantageously but in a non-limiting way, the second guiding element 25 extends to the second end portion 20b of the base portion 20, particularly, the pressing portion 25f extends above the second base portion 20 from a midline portion of the base portion to the second end portion of the second base portion 20 itself. In other words, the second guiding element 25 extends along a development direction, substantially parallel to the development direction of the second base portion 20, between a first and second end portions. The first end portion of the guiding element 25 is disposed at the ejection opening 24 of the second lower blowing device 22 while the second end portion of the guiding element 25 is disposed at the second end portion 20b of the second base portion 20.

From the structural point of view, the second guiding element 25 can comprise, as illustrated in the attached figures, a plate made for example of a metal material in a single piece. In a preferred but non-limiting embodiment of the invention, the descending section 25a and abutment section 25d of the second guiding element 25 are unitarily joined to each other while the pressing section 25f comprises a distinct body; advantageously the pressing section 25f is constrained to the descending section or abutment section by an adjusting member 35 (see Figure 1 C, for example) configured for enabling to relatively displace said pressing section 25f and the descending section 25a along a direction substantially parallel to the development direction of the guiding element 25 itself and/or along a direction substantially parallel to the direction of the gas ejected from the second lower blowing device 22. Advantageously, as illustrated in Figure 1 D for example, also the adjusting member 35 can be connected to the control unit 13 (see the connecting line q shown in Figure 1 D for example) which can be configured for commanding the adjustment of the position of the pressing section 25f by controlling the member 35.

As it is visible in Figure 1 B for example, the folding device 1 can comprise at least one adjusting member 26 engaged, on one side, with the supporting frame 2 and, on the other side, with the second guiding element 25; said adjusting member 26 being configured for relatively moving the second guiding element 25 with respect to the supporting frame 2 along an adjustment direction R3 (Figure 1 B) towards or away from the supporting surface 21 of the second base portion 20. The adjustment direction R3 is substantially parallel to a direction of the gas ejected from the ejection opening 24; the adjusting member 26 is configured for enabling to adjust the distance between the second guiding element 25 and supporting surface 21 of the second base portion 20. Particularly, the adjusting member 26 can comprise for example: a slide movable along a guide the position thereof is adjustable by pushing a screw, a slide, a ring nut, a chain, a belt. Advantageously, as illustrated in Figure 1 D for example, also the adjusting member 26 can be connected to the control unit 13 (see the connecting line m shown in Figure 1 D for example) which can be configured for commanding the adjustment of the position of the guiding element along the adjustment direction R3 by controlling the member 26.

As it is visible in Figure 1 B for example, the folding device 1 can further comprise at least one further adjusting member 27 engaged, on one side, with the supporting frame 2 and, on the other side, with the second guiding element 25. Said further adjusting member 27 is configured for relatively moving the second guiding element 25 with respect to the supporting frame 2 along an adjustment direction transversal to the development direction of the second base portion 20 and transversal to a direction of the gas ejected from the ejection opening 24. Specifically, the further adjusting member 27 can comprise for example: a worm, a slide, a ring nut, a chain, a belt. Advantageously, as illustrated in Figure 1 D for example, also the adjusting member 27 can be connected to the control unit 13 (see the connecting line n shown in Figure 1 D for example) which can be configured for commanding the adjustment of the position of the guiding element 25 by controlling the member 27.

As hereinbefore described, the semi-finished product 50 can comprise at least one transversal end sheet having a single sheet (see Figure 20 for example); under such condition, the second lower blowing device 22, when said sheet moves, is configured for ejecting a gas flow adapted to raise said sheet with respect to the central sheet 51 (Figures 21 and 22). The second guiding element 25 is disposed at a predetermined distance from the supporting surface 21 in order to prevent the single end sheet from contacting the abutment section 25d; after advancing the semi-finished product along the direction A, the end sheet contacts the descending section 25a which enables the further fold of the sheet. As it is visible in Figure 28 for example, the semi-finished product 50 can have a transversal end sheet 70 comprising a first and second portions 71 , 72. Under such condition, the second lower blowing device 22, when said sheet moves, is configured for ejecting a gas flow adapted to raise the first and second portions 71 and 72 of the sheet 70 with respect to the central sheet 51 (Figures 29 and 30). The second guiding element 25 is disposed at a predetermined distance from the supporting surface 21 in order to prevent the first portion 71 from contacting the abutment section 25d enabling at the same time to fold the second portion 72 with respect to the first portion 71 as illustrated in Figure 29; after advancing the semifinished product 50 along the direction A, the end sheet 70 contacts the descending section 25a which enables a further fold of the sheet 70. After the passage of the sheet 70 from the descending section 25a, the first and second portions 71 , 72 are completely folded above the central sheet as schematically illustrated in Figure 33.

Considering again the folding device illustrated in Figure 1 B, it is shown the upper blowing device 16 defining a first blowing device 16; the upper tool 9 of the folding device 1 can comprise - in a non-limiting way - a second upper blowing device 30 disposed above the second lower blowing device 22 and at the second guiding element 25. The second upper blowing device 30 comprises at least one channel 31 having an ejection opening 32 which is substantially interposed between the supporting surface 21 of the second base portion 20 and the second guiding element 25. As it is visible in Figure 1 C, the ejection opening 24 of the upper blowing device 30 has a minimum distance D1 1 from the supporting surface 21 of the second base portion 20 less than the minimum distance between the stop second 25d of the second guiding element 25 and the supporting surface 21 of the base portion 20. The minimum distance D1 1 between the ejection opening 32 of the second upper blowing device 30 and supporting surface 21 of the second base portion 20 is comprised between 1 and 200 mm, still more particularly between 3 and 20 mm.

Moreover, the ejection opening 32 is further interposed - along a direction parallel to the direction of the gas ejected from the second lower blowing device 22 - between the abutment section 25d of the second guiding element 25 and supporting surface 21 .

More specifically, the second upper blowing device 30 is configured for ejecting from the respective ejection opening 32 a gas flow having a direction substantially parallel to the advancement direction A of the semi-finished product 50 and configured for enabling a second fold of the transversal end sheet of the semi- finished product 50 previously folded by the first lower blowing device 22. Particularly and as it is visible in Figure 1 C for example, the second upper blowing device 30 is configured for ejecting a gas flow directed towards the second guiding element 25. De facto, the first and second blowing devices 16, 30 are configured for ejecting respective gas flows having opposite senses and parallel to the advancement direction A of the semi-finished product 50.

As hereinbefore described, the second lower blowing device 22 enables a first fold of the transversal end sheet as illustrated in Figures 21 and 22, for example; particularly, the device 22 enables to raise the transversal end sheet from the central sheet 51 towards the second upper blowing device 30 and towards the second guiding element 25. The second upper blowing device 30 is configured for ejecting a flow adapted to hit the transversal end sheet previously folded (raised) of the device 22 in order to further fold the sheet as for example illustrated in Figure 23: in this way, the upper blowing device 30 enables to correctly promote the insertion of the transversal end sheet below the guiding element 25.

The second upper blowing device 30 can advantageously comprise a plurality of channels 31 each of them has an ejection opening 32; the second upper blowing device 30 is configured for ejecting, from each of said ejection openings 32, a respective gas flow having a direction substantially parallel to the advancement direction A of the semi-finished product 50 for enabling a second fold of the transversal end sheet of the semi-finished product 50. Optionally, the second upper blowing device 30 comprises a number of channels 31 and of respective ejection openings 32 equal to or comprised between 2 and 10, particularly equal to or comprised between 2 and 6.

As schematically shown in Figure 1 D, the second upper blowing device 30 is connectable to the supplying unit 102 (see the connecting lines d' schematically shown in Figure 1 D, for example). The second upper blowing device 30 comprises at least one flow adjusting member 33, particularly a solenoid valve, configured for defining a first operative condition of the second upper blowing device 30 wherein the same ejects the gas flow from the ejection opening 32; the flow adjusting member 33 is further configured for defining a second operative condition of the second upper blowing device 30 wherein the same prevents the gas flow from being ejected from the ejection opening 32. The flow adjusting device 33 of the second upper blowing device 30 is configured for alternately defining the first and second operative conditions as a function of the positions taken by the semi-finished product 50 with respect to the ejection opening 24 of the second lower blowing device 22.

Advantageously, the flow adjusting member 33 is connected to the control unit 13 (see the connecting line i in Figure 1 D) which is configured for:

o receiving the control signal from the sensor 29, o determining, as a function of said signal received from the sensor, the relative position of the semi-finished product 50 with respect to the position of the ejection opening 24 of the second lower blowing device 22,

o commanding, as a function of the position of the semi-finished product with respect to the ejection opening of the second lower blowing device 22, and as a function of a moving speed of the semi-finished product along the advancement direction A, the first and second operative conditions of the second upper blowing device 30 according to sequences spaced so that the gas flow ejected at time intervals, can enable a second fold of the transversal end sheet of the semi-finished product 50.

More specifically, the control unit 13 is configured for determining, as a function of the signal received from the sensor 29, and as a function of the moving speed of the semi-finished product 50 along the advancement direction A, the second operative condition of the second lower and upper blowing devices 22, 30; particularly, the control unit 13 is configured for:

> commanding, as a function of the position of the semi-finished product with respect to the ejection opening 24 of the second lower blowing device 22, and as a function of an advancement speed of the semi-finished product along the advancement direction A, the second operative condition of the lower blowing device,

> commanding, as a function of the position of the semi-finished product with respect to the ejection opening 24 of the second lower blowing device 22, and as a function of an advancement speed of the semi-finished product along the advancement direction A, the second operative condition of the second upper blowing device 30, the control unit 13 is configured for commanding the second operative condition of the second upper blowing device 30 after commanding the second operative condition of the flow adjusting member 28 of the second lower blowing device 22.

As hereinbefore described, commanding at time intervals the second lower and upper blowing devices can be done as a function of the position of the semifinished product 50 with respect to the opening 24. As an alternative, the control unit 13 can command the second operative condition of the second upper blowing device 30 as a function of the position and moving speed of the semi-finished product with respect to the opening 32 of the device 30 itself.

As hereinbefore described, commanding the second operative condition (blowing condition) to the device 30 is done at time intervals so that the gas ejection is discontinuous and is performed only during predetermined time intervals. However, it is not excluded the possibility of defining a condition of the second upper blowing device 30 wherein the same continuously ejects a gas flow during the passage of semi-finished products 50.

As hereinbefore described, the semi-finished product 50 can comprise at least one transversal end sheet having a single sheet. The second upper blowing device 30 is adapted to eject a gas flow having the same sense of advancement of the semi-finished product 50 (this sense is coincident with the movement of the semi-finished product); under such condition, when the single sheet moves from the second lower blowing device 22, this is raised (Figure 21 ): before the single sheet 70 reaches the descending section 25a, the second blowing device 30 ejects a gas flow adapted to further fold the single sheet 70 in order to enable to insert the sheet itself inside the descending section 10a (Figure 23).

As hereinbefore described, the semi-finished product 50 can have a transversal end sheet 70 comprising a first and second portions 71 , 72. Under such condition, when the sheet 70 moves from the second lower blowing device 22, the first and second portions 71 , 72 are raised as hereinbefore described and as shown in Figure 29: before the sheet 70 reaches the descending section 25a, the second upper blowing device 30 is configured for emitting a gas flow against the sheet 70 adapted to further fold the first portion 71 with respect to the central sheet 51 and second portion 72 with respect to the first portion 71 in order to enable to insert the sheet 70 itself inside the descending section 25a (Figure 31 ).

Due to orientation of the second upper blowing device 30 (designed to eject a gas flow coincident with the advancement direction of the semi-finished product 50), the same is adapted to enable to fold a rear transversal end sheet of the semifinished product 50 considered with reference to the advancement direction A of the semi-finished product 50 itself (see Figures 19-26 and 27-34). De facto, in case of a semi-finished product 50 having a front and rear transversal end portions 60 and 70, the folding device 1 can advantageously comprise a folding device 1 as illustrated in Figures 1 B and 1 D, in other words comprising: a first lower blowing device 6, a first guiding element 10, optionally a first upper blowing device 16, a second lower blowing device 22, a second guiding element 25, optionally a second upper blowing device 30.

However, it is not excluded the possibility of using a folding device 1 as illustrated in Figure 1 wherein the same comprises only: a frame 2, a base portion 4, a lower blowing device 6, a guiding element 10 and optionally an upper blowing device 16. In such configuration, the folding device 1 can be used for folding a semi- finished product 50 having a transversal end sheet, particularly a front one, as illustrated in Figures 3-10 and/or 1 1 -18.

In case the semi-finished product 50 has only a rear end sheet 70 (this condition is not illustrated in the attached figures), the folding device can only comprise: a frame 2, a base portion 20, a lower blowing device 22, a guiding element 25 and optionally an upper blowing device 30. In such configuration, the folding device 1 can be used for folding a semi-finished product 50 having a transversal end sheet 70, particularly a rear one, as illustrated in Figures 19-26 and/or 27-34. Folding plant

Moreover, it is an object of the present invention a folding plant 100 comprising at least one fixed structure 101 to which a supporting frame 2 is engaged, the folding device 1 , according to anyone of the following claims and/or according to the above given description (see Figure 1 D).

The plant 100 comprises at least one transporting member 103 engaged with the fixed structure 101 and configured for engaging at least one semi-finished product 50 made of sheet material and for moving it along an operative path along an advancement direction A; the folding device is constrained to the fixed structure 101 at the operative path: the folding device 1 is configured for receiving the moving semi-finished product 50 displaced by the moving member 103 and for enabling to fold at least one transversal end sheet of said semi-finished product 50.

More particularly and as it is visible in Figure 2 for example, the transporting member 103 comprises:

> a first and second conveyor belts 105, 106 overlapped on each other and extending laterally the folding device 1 along the advancement direction of the semi-finished product 50; the first and second conveyor belts 105, 106 are configured for receiving between them the semi-finished product 50 and for moving it along the advancement direction A,

> a third and fourth conveyor belts 107, 108 overlapped on each other and extending laterally the folding device 1 along the advancement direction of the semi-finished product 50 opposite to the first and second conveyor belts 105, 106; the third and fourth conveyor belts 107, 108 are configured for receiving between them the semi-finished product 50 and for moving it along the advancement direction A. De facto, as it is visible in Figure 2, the folding device 1 is disposed on the operative path between the first and second conveyor belts, on one side and the third and fourth conveyor belts, on the other side.

Still more particularly, the transporting member 103 is configured for gripping the opposite longitudinal end portions of the semi-finished product for moving it - by the movements of the conveyor belts 105, 106, 107, and 108 - along the advancement direction A. As it is visible in Figure 2, the semi-finished product is substantially laterally pinched and moved along the direction A: the folding device is interposed between the belts 105, 106, 107, 108 and receives the moving semi- finished product.

Advantageously, as illustrated in Figure 2, the control unit 13 is connected to the transporting member 103 (see the connecting line t schematically illustrated in Figure 2); the control unit 13 is configured for commanding and adjusting the movement of said transporting member 103 for controlling a movement speed of the belts and therefore a relative movement speed of the semi-finished product 50 along the advancement direction A.

Process

Moreover, it is an object of the present invention a process of folding a semi- finished product 50 of sheet material; said folding process is performed by a folding device according to anyone of the following claims and/or according to the above given description.

The process comprises a step of moving a flat semi-finished product 50 of sheet material along an advancement direction A. The moving step is performed by the transporting member 103 which enables to move the semi-finished product along the direction A at a speed constantly greater than 20 m/min, particularly comprised between 60 and 250 m/min. The sheet semi-finished product is then moved to the lower blowing device 6: the relative position of the semi-finished product 50 with respect to the ejection opening 8 is determined by the control unit 13 connected to the sensor 12 (the steps of moving and detecting the semi-finished product 50 are outlined in Figures 3 and 1 1 , for example).

When the end sheet is above the ejection opening 8 of the lower blowing device 6, the process comprises ejecting a gas flow, through said opening 8, towards the semi-finished product 50: the ejecting step enables a first fold of the transversal end sheet with respect to the central sheet 51 away from the ejection opening 8 of the lower blowing device 6 as illustrated in Figures 4 and 12 for example. Figure 4 schematically shows raising a sheet comprising a single portion, while Figure 12 schematically shows raising a sheet 60 having a first and second portions 61 , 62. As schematically shown in Figure 1 A, the step of ejecting the gas flow through the lower blowing device 6 comprises ejecting said flow along a transversal direction, particularly normal, to the flat semi-finished product 50 towards the upper tool 9 of the folding device 1 . More particularly, the step of ejecting the gas flow from the device 6 is discontinuously performed at predetermined time intervals - by means of the flow adjusting member 1 1 - so that said gas flow can substantially act on the transversal end sheet of the semi-finished product. De facto, the gas flow is only ejected on the transversal end sheet: the step of ejecting the gas is suspended during the passage of the central sheet above the ejection opening 8 of the blowing device 6.

The process can comprise - in a non-limiting way - a further step of ejecting a gas flow by the upper blowing device 16, simultaneously or immediately after the step of ejecting the gas flow from the lower blowing device 6. The gas flow ejected by the upper blowing device 6 hits the transversal end sheet folded by the lower blowing device 6 for enabling the further fold of said transversal end sheet. Advantageously, the gas flow ejected from the upper blowing device 16, has an ejection direction substantially parallel and a sense opposite to the advancement direction A of the semi-finished product 50 and enables the further fold of a front transversal end sheet as illustrated in Figures 7 and 15.

After the step of ejecting the gas flow from the device 6, and optionally from the device 16, the process comprises moving the semi-finished product 50 along the advancement direction A so that the folded transversal end sheet (for example sheet 60) contacts the descending section 10a of the guiding element 10 which enables the further fold of said transversal end sheet above the central sheet 51 (see Figures 9 and 17 for example). Actually, the guiding element 10 enables to complete the step of folding the sheet 60 above the central sheet 51 previously folded by the lower blowing device 22 and optionally by the upper blowing device 16.

The semi-finished product can comprise both the front transversal end sheet 60 and the rear transversal end sheet 70; with such configuration, the front sheet is folded by the above described steps, in other words by moving the semi-finished product 50 above the device 6, optionally at the device 16, and by the guiding device 10. With reference to the step of folding the rear end sheet 70, the process can comprise the further following steps.

The flat semi-finished product 50 of sheet material is moved along the advancement direction A by the transporting member 103 at a speed constantly greater than 20 m/min, particularly comprised between 60 and 250 m/min. The sheet semi-finished product exiting the guiding element 10, is guided by the transporting member 103 to the second lower blowing device 22: the relative position of the semi-finished product 50 with respect to the ejection opening 24 is determined by the control unit 13 connected to the sensor 29 (the septs of moving and detecting the semi-finished product 50 are schematically shown in Figures 9 and 26 for example).

When the rear end sheet 70 is above the ejection opening 24 of the second lower blowing device 22, the process provides to eject through said opening 24 a gas flow towards the semi-finished product 50: the ejecting step enables a first fold of the transversal end sheet with respect to the central sheet 51 away from the ejection opening 24 of the second lower blowing device 22 as illustrated in Figures 21 and 29 for example. Figure 21 schematically shows the step of raising the sheet 70 which comprises a single portion while Figure 29 schematically shows the step of raising the rear sheet 70 which has a first and second portions 71 , 72. As schematically shown in Figure 1 C, the step of ejecting the gas flow through the second lower blowing device 22 provides to eject said flow along a transversal direction, particularly normal, to the flat semi-finished product 50 towards the second guiding element 29. More particularly, the step of ejecting the gas flow from the device 22 is discontinuously performed at predetermined time intervals - by means of the flow adjusting member 28 - so that said gas flow can act substantially on the rear end sheet 70 of the semi-finished product 50.

De facto, the gas flow is ejected only on the rear end sheet: the step of ejecting the gas is suspended during the passage of the central sheet 51 above the ejection opening 24 of the second blowing device 22.

The process can comprise - in a non-limiting way - a further step of ejecting a gas flow by the second upper blowing device 30, simultaneously or immediately after the step of ejecting the gas flow from the lower blowing device 22. The gas flow ejected by the upper blowing device 30 hits the rear transversal end sheet folded by the second lower blowing device 22 for enabling the further fold of said rear end sheet 70.

Advantageously, the gas flow ejected from the second upper blowing device 30 has an ejection direction substantially parallel and sense coincident to the advancement direction A of the semi-finished product 50 and enables the further fold of a rear transversal end sheet as illustrated in Figures 23 and 31 .

After the step of ejecting the gas flow from the device 22, and optionally from the device 30, the process provides to move the semi-finished product 50 along the advancement direction A so that the folded rear end sheet 70 contacts the descending section 25a of the second guiding element 25 which enables the further fold of said rear end sheet 70 above the central sheet 51 (see Figures 25 and 33 for example). De facto, the second guiding element 25 enables to complete the step of folding the sheet 70 above the central sheet 51 previously folded by the second lower blowing device 22 and optionally by the second upper blowing device 30.

It is observed that Figures from 19 to 34 schematically show the steps of folding a rear transversal end sheet 70 of a semi-finished product wherein the front end sheet 60 is non folded - in a non-limiting way. When the process provides to fold the front end sheet 60 before the step of folding the rear transversal end sheet 70, the semi-finished product 50 moving from the element 25 and device 22, will have the sheet 60 folded above the central sheet 51 (this condition is not illustrated in the attached figures). However, the process can provide to fold the sheet 70 before the step of folding the sheet 60 by the folding device 1 as illustrated in Figure 1 D. In such configuration, during the step of folding the rear transversal end sheet 70, the front transversal end sheet is not already folded as illustrated in Figures 19-26 and 27-34.

When the process comprises the step of folding the sheet 60 before folding the sheet 70, the configuration of the folding device would be one illustrated in Figure 1 B. With such configuration, during the step of folding the front transversal end sheet 60, the rear transversal end sheet 70 is not already folded as illustrated in Figures 3-10 and 1 1 -18.