Packaging assembly for forming and sealing a plurality of packs containing a pourable food product

1. A packaging assembly configured to form and seal a plurality of packs containing a pourable food product starting from a tube of packaging material; said assembly comprising:

at least a pair of tracks; and

at least a pair of moving elements, which are cyclically movable along said tracks, respectively;

each said moving element comprising at least one forming unit configured to cooperate with said tube so as to surround partially a portion of said tube destined to form a main portion of one respective pack; and at least one sealing unit configured to cooperate with said tube so as to sequentially seal said tube at predetermined consecutive cross sections, each pair of consecutive cross sections forming opposite sealing bands of one respective pack;

each said forming unit being mounted onto the respective moving element in a linearly movable manner towards and away from the corresponding sealing unit mounted onto the same moving element.

2. The packaging assembly as claimed in claim 1 , wherein said tube is fed to said assembly between said tracks, along an advancement straight direction; each forming unit being linearly movable towards said corresponding sealing unit along said advancement straight direction while the moving element carrying both the forming unit and the sealing unit advances parallel to said advancement straight direction.

3. The packaging assembly as claimed in claim 2 , further comprising actuator means configured to control linear movement of each said forming unit towards the corresponding sealing unit.

4. The packaging assembly as claimed in claim 3 , wherein said actuator means comprise, for each track, at least one cam surface fixed with respect to the track, and a cam follower carried by the respective moving element.

5. The packaging assembly as claimed in claim 4 , wherein said cam surface extends along said advancement straight direction and is configured to cooperate with the respective cam follower so as to produce a movement of the cam follower transversal to said advancement straight direction,

and wherein each moving element comprises a lever mechanism for converting said transversal movement of the respective cam follower into said linear movement of the respective forming unit towards and away from the corresponding sealing unit.

6. The packaging assembly as claimed in claim 5 , wherein each forming unit is cyclically moved by the respective cam surface, cam follower and lever mechanism between:

a first position, in which said forming unit is at a maximum distance from the corresponding sealing unit; and

a second position, in which said forming unit is at a minimum distance from the corresponding sealing unit.

7. The packaging assembly as claimed in claim 5 , wherein each lever mechanism comprises an oscillating member hinged at its fulcrum on the respective moving element; each oscillating member having a first portion articulated on the respective forming unit, and a second portion carrying the respective cam follower.

8. The packaging assembly as claimed in claim 7 , wherein each lever mechanism further comprises an elongated member hinged, at one axial end, to said first portion and, at the opposite axial end, to the respective forming unit.

9. The packaging assembly as claimed in claim 3 , wherein said actuator means comprise, for each moving element, at least one first interaction element carried by the respective forming unit and a second interaction element carried by the corresponding sealing unit, movable together with the sealing unit towards and away from said tube between a retracted and an advanced position, and cooperating with said first interaction element to cause said linear movement of said forming unit towards said sealing unit.

10. The packaging assembly as claimed in claim 9 , wherein each forming unit is mounted onto the respective moving element in a slidable manner along at least one linear guide, and wherein said first interaction element is mounted laterally onto the respective forming unit and is movable, along said advancement straight direction, from an upper position to a lower position by way of said linear guide.

11. The packaging assembly as claimed in claim 10 , wherein said first interaction element is retained in said upper position when said second interaction element is in said retracted position, and wherein said first interaction element moves in said lower position when said second interaction element moves from said retracted position to said advanced position.

12. The packaging assembly as claimed in claim 11 , wherein said first interaction element includes a lower part, said first interaction element comprising a cam surface arranged on its lower part and defining a main portion substantially transverse to said advancement straight direction and an operative portion having a recess; and wherein said second interaction element is mounted laterally onto the respective sealing unit and is movable, along a direction transverse to said advancement straight direction, from said retracted position, in which it cooperates with said main portion, to said advanced position, in which it cooperates with said operative portion.

13. The packaging assembly as claimed in claim 1 , wherein each forming unit is mounted onto the respective moving element in a slidable manner along at least one linear guide.

14. The packaging assembly as claimed in claim 1 , wherein said tracks define respective endless paths comprising:

respective operative branches between which said tube is fed, and along which each said forming unit and each said respective sealing unit cooperate with said tube; and

respective return branches along which each said forming unit and each said respective sealing unit are detached from the tube;

each said forming unit being linearly movable towards the corresponding sealing unit while the moving element advances along the respective operative branch.

15. The packaging assembly as claimed in claim 1 , wherein each forming unit comprises a volume control device cyclically drivable between:

an operative position, in which, in use, said volume control device cooperates with said tube and with the volume control device of another forming unit to form the main portion of one respective pack; and

an idle position, in which, in use, said volume control device is detached from said tube;

and wherein each said sealing unit comprises a sealing device cyclically drivable between:

an operative position, in which, in use, said sealing device cooperates with said tube and with the sealing device of another sealing unit to form the sealing bands of said packs; and

an idle position, in which, in use, said sealing device is detached from said tube or from said pack;

each said forming unit being linearly movable towards the corresponding sealing unit while said volume control device is in said operative position, and while said sealing device is moving towards said operative position.

16. The packaging assembly as claimed in claim 15 , further comprising actuator means configured to automatically control the cyclic displacement of said volume control devices and said sealing devices between said operative and idle positions.

17. The packaging assembly as claimed in claim 16 , wherein said actuator means comprise, for each track, further cam surfaces, fixed with respect to the track, and further cam followers carried respectively by said forming units and said sealing units.

18. The packaging assembly as claimed in claim 17 , wherein said tube is fed to said assembly along an advancement straight direction, and wherein said further cam surfaces extend along said advancement straight direction and are configured to produce a transversal movement of the respective cam followers traverse to said advancement straight direction.

19. The packaging assembly as claimed in claim 15 , wherein said tracks define respective endless paths comprising respective operative branches between which said tube is fed, and along which each said forming unit and each said respective sealing unit cooperate with said tube, and wherein the movement of each volume control device along the respective operative branch is defined by a combination of the cyclic displacement of the volume control device from said idle position to said operative position with said linear movement of the respective forming unit towards the corresponding sealing unit.

20. The packaging assembly as claimed in claim 1 , wherein each moving element and the respective track define a linear motor.

21. The packaging assembly as claimed in claim 1 comprising a plurality of said moving elements cyclically movable along one of said tracks and a plurality of said moving elements cyclically movable along an other of the tracks; the moving elements moving along the one track being independently movable with respect to each other and cooperating with corresponding moving elements moving along the other track, and the moving elements moving along the other track being independently movable with respect to each other and cooperating with corresponding moving elements moving along the one track.