Process and apparatus for manufacturing pneumatic tyres

Abstract

In a process of manufacturing pneumatic tyres, a carcass sleeve is made which includes at least one carcass ply provided with axially opposite flaps turned up around annular anchoring structures, so as to form respective loops. An outer sleeve is positioned around the carcass sleeve, and the latter is radially expanded in order to cause application of same against a radially internal surface of the outer sleeve. After each of the end flaps has been turned up and before radial expansion, only a portion belonging to each of the loops and extending substantially parallel to the respective annular anchoring structure is submitted to a step of carrying out heating under pressure, to make each loop integral with the annular anchoring structure and prevent the turned-up ply/plies from even partly slipping off, during the subsequent radial-expansion step of the carcass sleeve and vulcanisation step of the tyre.

1 - 49 . (canceled) 
     
     
         50 . An apparatus for manufacturing tyres, comprising:
 a forming drum having at least one radially external surface;   devices capable of applying at least one carcass ply around said radially external surface, said at least one carcass ply having axially opposite end flaps;   devices capable of coaxially engaging an annular anchoring structure around each of the end flaps;   devices for turning Lip each of the opposite end flaps of said at least one carcass ply around a respective annular anchoring structure so as to enclose said annular anchoring structure in a loop, in order to make a carcass sleeve;   at least one presser element capable of being placed close to each of two axially opposite ends of the forming drum, said at least one presser element having a contact surface capable of being only applied against a portion belonging to a respective loop;   devices capable of heating the loops at least at said portions;   devices capable of positioning an outer sleeve comprising at least one belt structure to a coaxially centered position around the carcass sleeve; and   shaping devices capable of shaping the carcass sleeve into a toroidal configuration.   
     
     
         51 . The apparatus as claimed in  claim 50 , wherein said at least one presser element is a roller capable of being applied against said portion. 
     
     
         52 . The apparatus as claimed in  claim 50 , wherein, in a radial section of the carcass sleeve, the loop extends over a predetermined length, a contact surface of the presser element having a width larger than or equal to about 5% of said predetermined length. 
     
     
         53 . The apparatus as claimed in  claim 50 , wherein, in a radial section of the carcass sleeve, the loop extends over a predetermined length, a contact surface of the presser element having a width smaller than or equal to about 30% of said predetermined length. 
     
     
         54 . The apparatus as claimed in  claim 50 , wherein, in a radial section of the carcass sleeve, the loop extends over a predetermined length, a contact surface of the presser element having a width larger than or equal to about 10% of said predetermined length. 
     
     
         55 . The apparatus as claimed in  claim 50 , wherein, in a radial section of the carcass sleeve, the loop extends over a predetermined length, a contact surface of the presser element having a width smaller than or equal to about 20% of said predetermined length. 
     
     
         56 . The apparatus as claimed in  claim 50 , wherein said contact surface is heated. 
     
     
         57 . The apparatus as claimed in  claim 50 , wherein the devices capable of heating the loops comprise at least one infrared source. 
     
     
         58 . The apparatus as claimed in  claim 50 , wherein the devices capable of heating the loops comprise at least one microwave source. 
     
     
         59 . The apparatus as claimed in  claim 50 , wherein the devices capable of heating the loops comprise a device for heating at least one wire by induction, which wire belongs to said annular anchoring structure. 
     
     
         60 . The apparatus as claimed in  claim 50 , wherein the shaping devices are capable of operating on the forming drum. 
     
     
         61 . The apparatus as claimed in  claim 50 , further comprising a shaping drum and devices capable of transferring the carcass sleeve and outer sleeve onto said shaping drum, shaping of the carcass sleeve being carried out on said shaping drum.