Machine for the automatic manufacture of pneumatic tires with a “biased” crown

A machine for the automatic manufacture of a tire, said machine comprising:

• a first zone referred to as “tire-building zone”, designed to produce a first annular entity that forms part of the tire, known as the “carcass entity”, which comprises at least one carcass ply provided with a first set of filamentary reinforcing elements referred to as “carcass reinforcers”, said tire-building zone for this purpose comprising a tire-building drum which has a drum central axis and which is mounted to rotate about said drum central axis, and a first conveying system which is designed to lay the carcass ply on the tire-building drum by winding it over said tire-building drum about the drum central axis so that the carcass reinforcers exhibit, with respect to a circumferential direction of the drum, a first angular orientation,
• a second zone referred to as the “finishing zone”, designed to produce a second annular entity that forms part of the tire, known as the “crown entity”, which comprises at least a tread, said finishing zone for this purpose comprising a shell ring mounted to rotate about a shell-ring central axis, and a second conveying system for laying the tread by winding on the shell ring about the shell-ring central axis,
• a shaping system designed to perform a shaping operation which causes the carcass entity present on the tire-building drum to expand radially in order to obtain a shaped carcass entity of toroidal shape,
• a third zone referred to as the “assembling zone”, designed to assemble the crown entity concentrically on the shaped carcass entity so as to obtain a tire, said assembling zone for this purpose comprising a transfer device of the transfer-ring type, which is designed to receive the crown entity coming from the shell ring of the finishing zone and transfer said crown entity onto and around the shaped carcass entity,
• a biasing system which is designed to bring into contact with the carcass entity, prior to the shaping operation, an annular structure referred to as a “biasing structure”, which is centered on the drum central axis and provided with a second set of filamentary reinforcing elements referred to as “biasing reinforcers” which exhibit, with respect to the circumferential direction of the drum, a second angular orientation, which is different from the first angular orientation of the carcass reinforcers, said biasing structure extending in such a way as to partially straddle the carcass ply along the drum central axis in a zone referred to as the “zone of overlap” so that during the shaping operation, the biasing reinforcers interact with the carcass reinforcers so as to modify, in the zone of overlap, the angular orientation of said carcass reinforcers with respect to the circumferential direction of the drum and so that in this way there is obtained a shaped and biased carcass entity,
• an automatic control unit which comprises at least a program enabling automatic execution by the machine of a cycle known as a “biased-crown tire manufacturing cycle” which comprises a step (a) of producing a crown entity in the finishing zone, a step (b) of preparing a shaped and biased carcass entity which step comprises a sub-step (b1) of creating a carcass entity in the tire-building zone and then a shaping and biasing sub-step (b2) during which said carcass entity coming from the tire-building zone is shaped and biased in order to obtain a shaped and biased carcass entity, said cycle making provision for the step (a) of producing the crown entity to overlap in time with at least part of the step (b) of preparing the carcass entity so that at least part of the production of the crown entity is performed in parallel with the preparation of the carcass entity, and then finally an assembling step (c) during which, in the assembling zone, the transfer device places and fixes the crown entity on the shaped and biased carcass entity so as to obtain a tire.