Process and plant for building tyres for vehicle wheels

Abstract

There is described a plant for building tyres for vehicle wheels, said tyres being of at least two different models, comprising at least a tyre building line (1) which in turn comprises:—a plurality of work stations (4, 4′, 5, 5′, 6, 12, 14) arranged according to a sequential series, each work station (4, 4′, 5, 5′, 6, 12, 14) being adapted for building at least one structural component of each tyre, assembling at least one elementary component;—at least one handling device (3) for the tyres being processed on the respective forming supports associated to each work station (4, 4′, 5, 5′, 6, 12, 14); and—at least one transfer device (2) adapted for transferring the tyre being processed on its forming support from any first work station (4, 4′, 5, 5′, 6, 12, 14) of said sequential series to any other second work station (4, 4′, 5, 5′, 6, 12, 14) not adjacent thereto of said sequential series, so that the tyre being processed on its forming support only passes in said first and second work station (4, 4′, 5, 5′, 6, 12, 14). There are also described a process for manufacturing tyres for vehicle wheels and a method for selecting work stations (4, 4′, 5, 5′, 6, 12, 14) of a tyre building plant.

1 - 51 . (canceled) 
     
     
         52 . A process for manufacturing tyres for vehicle wheels, the tyres comprising at least two different models, comprising the steps of:
 b) building at least a first and a second tyre model on respective forming supports, by building each structural component of the first and second tyre models at a plurality of work stations,   wherein step b) of building at least the first and second tyre models comprises:
 a first processing step of transferring and releasing, by a robotized arm of a transfer device, a first forming support holding the first tyre model from a first work station of the plurality of work stations to a second work station of the plurality of work stations, 
 a second processing step of transferring and releasing, by the robotized arm of the transfer device, a second forming support holding the second tyre model from a third work station of the plurality of work stations to a fourth work station of the plurality of work stations, wherein the second processing step occurs at the same time as the first processing step; and 
   wherein during the transfer of the first and second forming supports, the first and second forming supports follow different first and second paths, respectively.   
     
     
         53 . The process for manufacturing tyres according to  claim 52 , wherein the first work station is a first carcass structure building work station and the second work station is a first belt structure building work station. 
     
     
         54 . The process for manufacturing tyres according to  claim 53 , wherein the third work station is a second carcass structure building work station and the fourth work station is a second belt structure building work station. 
     
     
         55 . The process for manufacturing tyres according to  claim 54 , wherein step b) of building at least the first and second tyre models is preceded by a step of:
 a) arranging a plurality of elementary components of the first and second tyre models at the plurality of work stations.   
     
     
         56 . The process for manufacturing tyres according to  claim 55 , wherein step b) of building at least the first and second tyre models comprises, upstream of the first processing step, a step of:
 d) selecting the second work station based on tyre model, on a structural component to be built, and on availability of the work stations.   
     
     
         57 . The process for manufacturing tyres according to  claim 56 , wherein step b) of building the at least the first and second tyre models comprises, upstream of the first processing step, a step of:
 d) selecting the fourth work station based on tyre model, on a structural component to be built, and on availability of the work stations.   
     
     
         58 . The process for manufacturing tyres according to  claim 57 , wherein step b) of building at least the first and second tyre models comprises the steps of:
 i) building a carcass structure, the carcass structure comprising at least one carcass ply and a pair of annular anchoring structures;   ii) building a belt structure, the belt structure comprising at least one belt layer; and   iii) building a tread band.   
     
     
         59 . The process for manufacturing tyres according to  claim 58 , wherein, in at least one of the first and second tyre models, a bending ratio between the distance between a radially outer distance of the tread band and a line passing by laterally opposite ends of the tread band, measured on a equatorial plane of the tyre model, and a distance measured along a tyre chord between ends is more than or equal to, about 0.15. 
     
     
         60 . The process for manufacturing tyres according to  claim 59 , wherein the bending ratio is less than or equal to about 0.3. 
     
     
         61 . The process for manufacturing tyres according to  claim 59 , wherein the bending ratio is less than or equal to 0.45. 
     
     
         62 . The process for manufacturing tyres according to  claim 61 , wherein, in step ii), the at least one belt layer comprises a layer of textile or metal cords oriented circumferentially at 0°. 
     
     
         63 . The process for manufacturing tyres according to  claim 62 , wherein step iii) of building the tread band comprises step iii′) of applying a tread band in a position radially external to the belt structure. 
     
     
         64 . The process for manufacturing tyres according to  claim 63 , comprising a step of:
 iv) applying at least one portion of sidewalls of the tyre model being processed in a position axially external to the tyre model being processed.   
     
     
         65 . The process for manufacturing tyres according to  claim 64 , wherein step iii) of building the tread band comprises, prior to step iii′) of applying the tread band, a step of:
 iv′) applying at least one tread band underlayer in a position radially external to the belt structure. 
 
     
     
         66 . The process for manufacturing tyres according to  claim 65 , wherein at least one of steps iii′), iv″) or iv) is carried out by applying at least one continuous elongated element of elastomeric material according to side by side or at least partially overlapped coils. 
     
     
         67 . The process for manufacturing tyres according to  claim 66 , wherein at least one structural component is built by assembling at least one elementary component. 
     
     
         68 . The process for manufacturing tyres according to  claim 67 , further comprising a pre-step of feeding elementary components to at least one work station. 
     
     
         69 . The process for manufacturing tyres according to  claim 68 , wherein the forming support is a toroidal support. 
     
     
         70 . The process for manufacturing tyres according to  claim 69 , wherein the toroidal support has a radially external surface corresponding to a radially internal surface of the tyre being processed. 
     
     
         71 . The process for manufacturing tyres according to  claim 70 , wherein the first and second tyre models differ by size. 
     
     
         72 . The process for manufacturing tyres according to  claim 71 , wherein the first and second tyre models differ by structural components. 
     
     
         73 . The process for manufacturing tyres according to  claim 72 , wherein the first and second tyre models differ by elementary components.