Process and apparatus for tire manufacturing with optimized bead positioning

A system for building, in at least two stages, an unvulcanized tire carcass suitable for molding into a beaded, finished tire, the system comprising:

• a first stage expandable drum on which unvulcanized tire building components are layered to form a cylindrically shaped, unvulcanized tire carcass having carcass ends, with an annular bead encompassing and placed proximate each carcass end;
• the first stage drum having an inflatable bladder attached to opposite ends for turning up the respective carcass ends upon inflation;
• a second stage shaping drum on which the unvulcanized tire carcass is shaped for subsequent molding and vulcanization, the shaping drum having two ends and bead clamping segments located proximate each of the shaping drum ends for clamping the beads of tire carcass so that the beads do not move and become misaligned during the tire building operations on the shaping drum;
• and
• a bead tube transfer device that transfers the shaped tire carcass and its beads between the first stage drum and the second stage drum while precisely maintaining the separation distance between the carcass' beads, the carcass ends being held in a turned up position during this transfer so as to allow the carcass and its beads to be clamped by the shaping drum bead clamping segments such that the beads' axial separation distance continues on the shaping drum to be approximately the same as that set on the first stage drum;
• wherein the system is characterized in that:
• the bead tube transfer device has at least two main support rings configured and oriented to circumferentially encompass the ends of a tire carcass, the rings being mounted so that their axial separation distance can be varied and set to a desired bead spacing distance;
• bead tube flanges are circumferentially mounted on the rings, the bead tube flanges having a perforated axially-outer surface, the perforations allowing a vacuum to be imposed on a portion of the bead tube flange outer surface so as to aid in maintaining the carcass ends in a turned up position;
• and the bead tube flange outer surfaces have mounted thereon magnets for holding the beads proximate to the bead tube flanges;
• the bead tube transfer device further has at least two circumferentially-mounted vacuum rings positioned axially outward of and approximately parallel to the bead tube flanges on the main support rings, the vacuum rings configured to encompass the turned up carcass ends of the tire carcass, and the vacuum rings imposing a vacuum on a portion of the carcass turned up ends so as to aid in maintaining the carcass ends in a turned up position;
• and
• the tire carcass is held in the bead tube transfer device with a fixed bead separation distance by the combined action of the magnets, and the vacuums imposed by the vacuum rings and the bead tube flanges.