Process and drum for looping annular anchoring structures in a process for building tyres for vehicle wheels

Patent metadata

Field	Value
Publication number	US-11090892-B2
Application number	US-201916730335-A
Country	US
Kind code	B2
Filing date	Dec 30, 2019
Priority date	Mar 24, 2014
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

A process and a drum for looping annular anchoring structures in a process for building tyres for vehicle wheels includes: depositing a loop on a drum including a radially expandable/contractible intermediate annular portion and, in a position axially adjacent to the opposite axial ends of the intermediate annular portion, a pair of radially expandable/contractible lateral annular portions; associating an annular anchoring structure with a radially outer annular surface portion of the loop defined at the intermediate annular portion; and turning up each of opposite end edges of the loop on the annular anchoring structure through the lateral annular portions as a result of a thrusting stress imparted by a respective lateral annular portion of the pair of lateral annular portions because of a synchronous radial movement and a synchronous axial displacement of a respective plurality of circumferentially adjacent first angular sectors.

First claim

The invention claimed is:

1. A drum for looping annular anchoring structures in a process for building tyres for vehicle wheels, comprising a radially expandable/contractible intermediate annular portion and, in a position axially adjacent to opposite axial ends of said intermediate annular portion, a pair of radially expandable/contractible lateral annular portions, the intermediate annular portion and the lateral annular portions being configured to support a loop, wherein each lateral annular portion of said pair of lateral annular portions comprises a plurality of circumferentially adjacent first angular sectors, wherein each of the circumferentially adjacent first angular sectors is capable of a synchronous radial movement and a synchronous axial displacement to cause a thrusting stress imparted by the respective lateral annular portion to turn up an end edge of the loop on an annular anchoring structure arranged at the intermediate annular portion;
wherein the drum is configured so that during the turning up, the annular anchoring structure is not rotated.

2. The drum according to claim 1 , wherein said intermediate annular portion comprises a plurality of circumferentially adjacent second angular sectors capable of being moved radially synchronously with each other.

3. The drum according to claim 2 , wherein said intermediate annular portion comprises, in a radially inner position with respect to each of said second angular sectors, a first elastic element acting to radially thrust a respective second angular sector.

4. The drum according to claim 1 , wherein each of said first angular sectors is slidably associated with a radially outer surface of a radially movable support body.

5. The drum according to claim 3 , wherein each of said second angular sectors is kept in a radial contracted position against said radial thrust by a pair of said first angular sectors axially opposite to each other.

6. The drum according to claim 1 , wherein each of said first angular sectors comprises a second elastic element acting to axially thrust an axially outer end thereof.

7. The drum according to claim 1 , wherein each of said first angular sectors comprises a contact element associated with an axially inner end thereof.

8. The drum according to claim 1 , comprising a locking assembly for stopping the axial movement of said first angular sectors.

9. The drum according to claim 8 , wherein said locking assembly comprises:
a pair of holes formed on said radially outer surface of said support body;
a pin associated with a respective first angular sector; and
a third elastic element acting between said pin and the respective first angular sector so that, in an axial locking condition of said first angular sector, a free end portion of said pin is housed inside one of said holes and, in an axial unlocking condition of said first angular sector, said free end portion of said pin is outside of said hole.

10. The drum according to claim 8 , wherein said locking assembly comprises, at an axially outer end of said first angular sectors:
a contrast ring; and
a plurality of balancing levers, each balancing lever having a first end pivoted at an axially outer end of a respective first angular sector and a second end configured to cooperate with said contrast ring when said first angular sector is in a condition of maximum expansion.

11. The drum according to claim 10 , wherein said locking assembly comprises:
a pair of holes formed on said radially outer surface of said support body;
a pin associated with a respective first angular sector; and
a third elastic element acting between said pin and the respective first angular sector so that, in an axial locking condition of said first angular sector, a free end portion of said pin is housed inside one of said holes and, in an axial unlocking condition of said first angular sector, said free end portion of said pin is outside of said hole;
wherein, when said second end of said balancing lever is not in contact with said contrast ring, said first angular sector is in said axial unlocking condition, and when said second end of said balancing lever is in contact with said contrast ring, said first angular sector reaches said axial locking condition.

12. The drum according to claim 8 , comprising an unlocking assembly for unlocking the axial movement of said first angular sectors.

13. The drum according to claim 12 , wherein said locking assembly comprises:
a pair of holes formed on said radially outer surface of said support body;
a pin associated with a respective first angular sector; and
a third elastic element acting between said pin and the respectice first angular sector so that, in an axial locking condition of said first angular sector, a free end portion of said pin is housed inside one of said holes and, in an axial unlocking condition of said first angular sector, said free end portion of said pin is outside of said hole;
wherein said unlocking assembly comprises a spigot configured to expel said free end portion of said pin from said hole when said first angular sector is radially contracted until a condition of maximum contraction is reached.

14. The drum according to claim 13 , wherein said spigot is arranged in a radially outer position with respect to a guide bar provided for guiding the radial movement of said first angular sector.

15. The drum according to claim 1 , comprising, at each of said opposite axial ends of said intermediate annular portion:
a screw-lead nut coupling; and
a plurality of levers each lever having a first end pivoted at a respective lead nut and a second end pivoted at the support body.

16. The drum according to claim 15 , wherein said screw comprises a first axial portion with a right-handed thread and a second axial portion with a left-handed thread, or vice-versa.

17. The drum according to claim 1 , wherein an elastic thrust is exerted on each of said first angular sectors to achieve an axial displacement thereof towards a middle plane of the drum.

Assignees

• Pirelli

Inventors

• Marchini Maurizio
• Scarmagnan Saraiva Henrique
• Lepore Marco
• De Col Christian

Classifications

• B29D30/48 Primary

  Bead-rings or bead-cores (from wire B21F37/00); Treatment thereof prior to building the tyre · CPC title

• B29D30/50 Primary

  Covering, e.g. by winding, the separate bead-rings or bead-cores with textile material, e.g. with flipper strips (folding textile layers around bead-rings or bead-cores B29D30/18, B29D30/32; jointly covering bead-rings or bead cores B29D30/34) · CPC title

• B29D2030/325

  the means being radially expandable and contractible · CPC title

• B29D30/36

  Expansion of tyres in a flat form {, i.e. expansion to a toroidal shape independently of their building-up process}, e.g. of tyres built by the flat-tyres method or by jointly covering two bead-rings · CPC title

• B29D30/245

  Drums for the single stage building process, i.e. the building-up of the cylindrical carcass and the toroidal expansion of it are realised on the same drum (expansion to a toroidal shape B29D30/36) · CPC title