In a method of manufacturing a pneumatic tire, a placement unit is moved relative to a forming drum in a drum circumferential direction to repeatedly perform a one-side step of delivering a reinforcing wire in a folded back state in a length from a central portion toward one side in the width direction of the forming drum and compression bonding the reinforcing wire to an innerliner of an outer surface of the forming drum, and after delivering the reinforcing wire in the length toward the one side in the width direction as described above, perform an other-side step of delivering the reinforcing wire in a folded back state in a length from the central portion toward an other side in the width direction of the forming drum and compression bonding the reinforcing wire to an outer surface of the innerliner.

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 for building tyres provides for building a carcass sleeve around a forming drum having an application diameter and two lateral half-portions axially moveable relative to each other. The carcass sleeve comprises at least one carcass ply coaxially engaged around each of the axially opposite end flaps thereof to an annular anchoring structure defining a fitting diameter smaller than the application diameter. The building of the carcass sleeve comprises: applying and stopping a leading end of a semi-finished product in form of continuous strip cut to size against a continuous surface of the forming drum; winding the semi-finished product in form of continuous strip cut to size circumferentially around the forming drum; joining a trailing end of the semi-finished product to the leading end at said continuous surface. The continuous surface is extended only partly around the forming drum. The semi-finished product, except for the leading end and the trailing end, is laid against a discontinuous circumferential surface of the forming drum adjacent to the continuous surface and belonging to the two lateral half-portions.

An apparatus for manufacturing tyres for vehicle wheels wherein each tyre includes a carcass structure formed starting from at least one carcass ply laid on a forming support extended along a longitudinal axis. The apparatus includes at least one device for positioning at least one annular anchoring structure on at least one end edge of the carcass ply, the positioning device being circumferentially extended around the longitudinal axis of the forming support and axially movable with respect to the forming support between an operating position distal from the forming support and at least one operating position close to the forming support. The apparatus further includes a device for turning up the end edge of the carcass ply around the annular anchoring structure, the turning up device being circumferentially extended about the longitudinal axis of the forming support and axially movable for approaching/moving away to/from the forming support. The positioning device and the turning up device are radially expandable/contractible in a synchronous manner with respect to the longitudinal axis of the forming support and are settable in a plurality of different operating radial positions, each operating radial position being selected based on a respective radial dimension of the tyre to be manufactured.

A carcass ply is applied around an outer surface of a building drum according to an application diameter larger than the fitting diameter of a tyre. Coaxially engaged around each of the end flaps is an annular anchoring structure defining the fitting diameter. A pair of sidewalls is manufactured by laying of a continuous elongated element in the form of approached coils on the carcass sleeve. An outer sleeve, including at least one belt structure possibly associated with a tread band, is coaxially centered around the carcass sleeve. Through axial approaching of two halves forming the building drum, the carcass sleeve is shaped into a toroidal configuration to determine application of same against a radially internal surface of the outer sleeve.

A carcass ply is applied around an outer surface of a building drum according to an application diameter larger than the fitting diameter of a tire. Coaxially engaged around each of the end flaps is an annular anchoring structure defining the fitting diameter. A pair of sidewalls is manufactured by laying of a continuous elongated element in the form of approached coils on the carcass sleeve. An outer sleeve, including at least one belt structure possibly associated with a tread band, is coaxially centered around the carcass sleeve. Through axial approaching of two halves forming the building drum, the carcass sleeve is shaped into a toroidal configuration to determine application of same against a radially internal surface of the outer sleeve.

A tire building drum (10) is used to build a large green tire. The tire building drum (10) comprises: a cylindrical drum main body (12) haying an outer peripheral surface (14) a diameter of which is capable of being increased and reduced; and a coating (16) formed on the outer peripheral surface of the drum main body. The coating (16) includes a silicon layer (26) defining a surface of the coating (16), and the silicon layer has a surface roughness Ra of 10 m or greater. The tire building drum (10) requires no application of stearic acid onto the surface thereof in release of the green tire.

A tyre carcass building drum (1) having a longitudinal axis (3) and two half-drums (6) movable along the longitudinal axis (3) in opposite directions away from and towards a centre plane (4) of the drum (1), each one comprising a bead carrying device (16) defining a saddle and a turn-up device (41) designed to turn up a annular side portion (42) of a carcass ply around, and on the outside of a respective bead ring; the turn-up device (43) having an end portion arranged, at rest, along a peripheral annular portion (18) of the saddle (17) and shaped so as to define an extension of the curvilinear profile of the saddle (17); and thrust means (50) being provided to directly and independently exert an axial thrust and a radial thrust on the turn-up device (43). The invention also relates to an operating method of said drum.

An apparatus for manufacturing tires for vehicle wheels wherein each tire includes a carcass structure formed starting from at least one carcass ply laid on a forming support extended along a longitudinal axis. The apparatus includes at least one device for positioning at least one annular anchoring structure on at least one end edge of the carcass ply, the positioning device being circumferentially extended around the longitudinal axis of the forming support and axially movable with respect to the forming support between an operating position distal from the forming support and at least one operating position close to the forming support. The apparatus further includes a device for turning up the end edge of the carcass ply around the annular anchoring structure, the turning up device being circumferentially extended about the longitudinal axis of the forming support and axially movable for approaching/moving away to/from the forming support. The positioning device and the turning up device are radially expandable/contractible in a synchronous manner with respect to the longitudinal axis of the forming support and are settable in a plurality of different operating radial positions, each operating radial position being selected based on a respective radial dimension of the tire to be manufactured.

The building drum includes a support (20), a central shaft (30) and an outer circumferential surface coaxial with the axis of rotation of the drum. The building drum also has a principal cylindrical surface (100) axially bounded by a shoulder (101) extended by a lateral protuberance (102) for receiving the products which have to be assembled. Several segments together define the principal cylindrical surface, and those segments are being divided into first and second groups of adjacent segments (103a, 103b) mounted so as to move between a first position in which they are circumferentially juxtaposed and a second position in which the adjacent segments are radially offset. Several adjacent elbow levers (140) form the shoulder (101) and the protuberance (102) in the expanded position of the drum and each elbow lever (140) is mounted with articulation on the segment (103a, 103b) and on the support (20).