A forming drum has circumferentially consecutive sectors that are radially movable between a contracted condition and an expanded condition in which the sectors are radially moved away from a geometric axis in order to define a radially external abutment surface. Each sector has circumferentially opposite coupling portions, each having circumferential projections alternated with circumferential cavities. The projections of each sector are slidably engaged in the respective cavities of circumferentially adjacent sectors. From at least one of the projections, at least one support wing is extended having a first side and a second side that are respectively opposite. The first side coincides with a portion of the abutment surface and the second side at least partially overlaps one of the projections belonging to an adjacent sector. A process for building tyres employing the drum is also described.

A forming drum has circumferentially consecutive sectors that are radially movable between a contracted condition and an expanded condition in which the sectors are radially moved away from a geometric axis in order to define a radially external abutment surface. Each sector has circumferentially opposite coupling portions, each having circumferential projections alternated with circumferential cavities. The projections of each sector are slidably engaged in the respective cavities of circumferentially adjacent sectors. From at least one of the projections, at least one support wing is extended having a first side and a second side that are respectively opposite. The first side coincides with a portion of the abutment surface and the second side at least partially overlaps one of the projections belonging to an adjacent sector. A process for building tyres employing the drum is also described.

A carcass sleeve is situated in a radially external position with respect to a toroidal forming drum, arranged in a first radially contracted operative condition. The carcass sleeve is shaped according to a toroidal configuration while the forming drum is positioned inside the carcass sleeve. During shaping of the carcass sleeve, the forming drum is radially expanded up to a second radially expanded operative condition. Upon completed shaping, the carcass sleeve is coupled to the forming drum in the second operative condition. The forming drum, coupled to the shaped carcass sleeve, is arranged in proximity to at least one device for building at least one belt layer at a radially external position relative to the shaped carcass sleeve.

A carcass sleeve is situated in a radially external position with respect to a toroidal forming drum, arranged in a first radially contracted operative condition. The carcass sleeve is shaped according to a toroidal configuration while the forming drum is positioned inside the carcass sleeve. During shaping of the carcass sleeve, the forming drum is radially expanded up to a second radially expanded operative condition. Upon completed shaping, the carcass sleeve is coupled to the forming drum in the second operative condition. The forming drum, coupled to the shaped carcass sleeve, is arranged in proximity to at least one device for building at least one belt layer at a radially external position relative to the shaped carcass sleeve.

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.

A tire building drum is rotatably mounted on a central drive shaft and includes a center portion. A center mechanism for the drum is disposed in the center portion and includes a hub that seats on and is secured to the central drive shaft. An axially-extending piston seats on and extends circumferentially about the hub. A cylinder cooperates with the hub and the piston to form a pneumatic chamber. A plurality of links are connected to the piston and a plurality of segment bars are disposed about the circumference of the center mechanism. Each one of the segment bars is connected to selected links and seats between a lip of the cylinder and a distal end plate. When compressed air is introduced into the pneumatic chamber, the piston moves in an axial direction, actuating movement of the links and in turn actuating radial movement of the segment bars.

A tire building drum is rotatably mounted on a central drive shaft and includes a center portion. A center mechanism for the drum is disposed in the center portion and includes a hub that seats on and is secured to the central drive shaft. An axially-extending piston seats on and extends circumferentially about the hub. A cylinder cooperates with the hub and the piston to form a pneumatic chamber. A plurality of links are connected to the piston and a plurality of segment bars are disposed about the circumference of the center mechanism. Each one of the segment bars is connected to selected links and seats between a lip of the cylinder and a distal end plate. When compressed air is introduced into the pneumatic chamber, the piston moves in an axial direction, actuating movement of the links and in turn actuating radial movement of the segment bars.

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.

In a shaping station (13), a toroidal forming drum (23) is positioned within a carcass sleeve (12) comprising at least one carcass ply (3) associated with a pair of beads (6) in radially inner position. The carcass sleeve (12) is toroidally shaped by radial expansion of the forming drum (23). The forming drum (23) carrying the shaped carcass sleeve (12) is removed from the shaping station (13). Tyre components (7, 8, 9) are applied externally on the shaped carcass sleeve (12), carried by the forming drum (23). At the end of the shaping and during the application of the tyre components (7, 8, 9), axially inner sides of said beads (6) are arranged axially against respective circumferential axially outer portions (S1) of an abutment surface (S) carried by the expanded forming drum (23), having shape corresponding to an inner shape of the shaped carcass sleeve (12).

In a shaping station (13), a toroidal forming drum (23) is positioned within a carcass sleeve (12) comprising at least one carcass ply (3) associated with a pair of beads (6) in radially inner position. The carcass sleeve (12) is toroidally shaped by radial expansion of the forming drum (23). The forming drum (23) carrying the shaped carcass sleeve (12) is removed from the shaping station (13). Tyre components (7, 8, 9) are applied externally on the shaped carcass sleeve (12), carried by the forming drum (23). At the end of the shaping and during the application of the tyre components (7, 8, 9), axially inner sides of said beads (6) are arranged axially against respective circumferential axially outer portions (S1) of an abutment surface (S) carried by the expanded forming drum (23), having shape corresponding to an inner shape of the shaped carcass sleeve (12).