Process and apparatus for assembling tyres

1. A process for assembling tyres, comprising:

forming a carcass sleeve on a building drum, said carcass sleeve comprising a carcass ply attached to a pair of annular anchoring structures;

forming an outer sleeve on an auxiliary drum, said outer sleeve comprising at least one belt layer and a tread band;

using a first transfer unit, in the form of a first robotic arm with at least six movement axes, on the auxiliary drum for moving the auxiliary drum carrying the outer sleeve formed thereon to an assembly station;

picking up the outer sleeve from the auxiliary drum while the auxiliary drum is held by the first transfer unit at one axial end of the auxiliary drum, coaxially with a footstock of the assembly station at the other axial end of the auxiliary drum;

using a second transfer unit, in the form of a second robotic arm having at least six movement axes, for moving the building drum carrying the carcass sleeve formed thereon to the assembly station;

engaging the building drum carrying the carcass sleeve formed thereon to the footstock and a mandrel at the assembly station;

positioning the outer sleeve at a location radially external to the carcass sleeve formed on the building drum while the building drum is held in the assembly station by the mandrel at one axial end of the building drum and the footstock at the other axial end of the building drum;

coupling the carcass sleeve to said outer sleeve; and

removing the assembled tyre from the assembly station.

2. The process as claimed in claim 1 , further comprising removing the auxiliary drum from the assembly station; and

wherein the building drum is engaged to the mandrel before removing the auxiliary drum from the assembly station.

3. The process as claimed in claim 1 , wherein removal of the assembled tyre from the assembly station comprises:

engaging an unloading handling device on an outer surface of the tyre;

translating the unloading handling device for axially removing the tyre from the building drum; and

translating said unloading handling device for moving the tyre away from the assembly station.

4. The process as claimed in claim 1 , further comprising positioning the building drum in axial alignment between the mandrel and the footstock while they are mutually spaced apart; and

axially moving the footstock close to the mandrel before engaging the building drum to both of said mandrel and said footstock.

5. The process as claimed in claim 1 , further comprising engaging the auxiliary drum to the footstock by axially moving the auxiliary drum close to the footstock.

6. The process as claimed in claim 5 , wherein during axial moving of the auxiliary drum close to the footstock, the auxiliary drum is axially inserted into a grip unit carried by the assembly station and designed to pick up the outer sleeve from the auxiliary drum.

7. The process as claimed in claim 6 , wherein before moving the auxiliary drum close to the footstock, the grip unit is axially positioned so as to be located at an axially centered position relative to axial ends of the outer sleeve when engaging of the auxiliary drum to the footstock is completed.

8. The process as claimed in claim 1 , wherein said coupling the carcass sleeve to said outer sleeve comprises:

operatively coupling shaping devices carried by the assembly station to the building drum; and

shaping the carcass sleeve into a toroidal configuration for coupling said carcass sleeve to said outer sleeve.

9. The process as claimed in claim 1 , wherein picking up of the outer sleeve from the auxiliary drum comprises:

translating a grip unit carried by the assembly station in parallel to a geometric rotation axis of the auxiliary drum until positioning the grip unit around the outer sleeve carried by the auxiliary drum;

engaging the outer sleeve to the grip unit; and

axially translating the auxiliary drum for releasing said auxiliary drum from the outer sleeve.

10. The process as claimed in claim 9 , further comprising moving the auxiliary drum away from a condition of axial alignment with the grip unit after picking up the outer sleeve from the auxiliary drum.

11. The process as claimed in claim 6 , wherein positioning the outer sleeve at a location radially external to the carcass sleeve takes place through translation of the grip unit in parallel to a geometric rotation axis of the building drum until positioning the outer sleeve around the carcass sleeve.

12. The process as claimed in claim 8 , wherein operatively coupling the building drum to the shaping devices comprises engagement of a pair of retaining members with the building drum, each of said retaining members being in axially approached relationship with a respective half of the building drum.

13. The process as claimed in claim 12 , wherein each of said retaining members acts against a respective circumferential abutment edge carried by the building drum.

14. The process as claimed in claim 8 , comprising locking the annular anchoring structures relative to the building drum during coupling of the carcass sleeve to the outer sleeve.

15. The process as claimed in claim 14 , wherein concurrently with said locking, hermetically sealing the carcass sleeve at the annular anchoring structures.

16. The process as claimed in claim 12 , wherein each of said retaining members is brought into thrust relationship against a respective annular anchoring structure of said pair of annular anchoring structures.

17. The process as claimed in claim 13 , wherein engagement of each of said retaining members with the building drum comprises:

fastening a respective flanged element of the each retaining member relative to the building drum; and

pushing a respective sealing ring of the each retaining member against its respective circumferential abutment edge.

18. The process as claimed in claim 17 , wherein fastening of each flanged element takes place through screwing down of a respective threaded member operating in a respective pressurisation chamber of a respective hydraulic brake carried by each flanged element and operating on a central shaft of the building drum.

19. The process as claimed in claim 17 , wherein each sealing ring is pushed by respective circumferentially distributed sliding shoes which are movable in parallel with a geometric rotation axis of the building drum.

20. The process as claimed in claim 9 , comprising, after coupling the carcass sleeve to the outer sleeve:

disengaging the grip unit from the assembled tyre;

radially contracting the building drum; and

releasing the tyre being processed from the building drum.

21. The process as claimed in claim 8 , wherein said footstock is set in rotation for driving the building drum in rotation during rolling thereof after coupling the carcass sleeve to the outer sleeve.

22. The process as claimed in claim 1 , wherein said carcass ply is made by laying of elementary semifinished products on the building drum.

23. The process as claimed in claim 1 , wherein said at least one belt layer is made by laying of elementary semifinished products on the auxiliary drum.

24. The process as claimed in claim 5 , wherein said footstock is driven in rotation before engagement of the auxiliary drum for angularly positioning at least one drive key carried by the footstock.