Method and apparatus for control of dual collapsible mandrels

In a method for converting a generally hollow cylindrical green tire carcass into a generally toroidal tire employing a shaping drum having a rotatable central shaft having a rotational axis and first and second mandrels mounted on the shaft, each of the mandrels being divided into a plurality of like segments constrained to radial movement relative to the rotational axis of the shaft and defining an outer circumference for the receipt thereon of a bead ring of the carcass when disposed on the shaping drum, comprising the steps of

• defining a canming surface on each of the segments of each of the first and second mandrels, said camming surfaces of each mandrel facing respectively inboard of said drum and collectively defining respective common circular areas for camming engagement therewith of first and second circular cams axially and slidably disposed on the shaft and inboard of said camming surfaces of the segments,
• applying an axially directed force from a single source thereof substantially simultaneously to each of said circular cams to thereby move each of said circular cams into camming engagement with respective ones of said camming surfaces of the segments to substantially simultaneously urge each of the segments of each mandrel radially outwardly of the drum,
• substantially simultaneously converting said radial movement of each of the segments into respective rotational forces,
• substantially simultaneously transmitting said rotational forces associated with each of the segments of the first mandrel to all of the other segments of the first mandrel and transmitting said rotational forces associated with the segments of the second mandrel to all of the other segments of the second mandrel, whereby all of the segments of each of the first and second mandrels move substantially simultaneously in a like direction and to a like extent to uniformly shape said carcass.

A shaping drum having a transverse center plane, for use in the manufacture of vehicle tires wherein a generally hollow cylindrical green tire carcass, which includes a bead adjacent each of its opposite ends, is sealably secured at its beads to the circumferences of respective ones of first and second mandrels that are mounted on opposite sides of the transverse center plane for movement toward and away from one another on a central shaft having a longitudinal rotational axis, and while so sealably mounted, is inflated to enlarge the radial dimension thereof and to reposition the beads thereof to a desired separation distance that is representative of the desired width of the tire comprising

• first and second generally circular mandrels disposed in encircling relationship to said central shaft, each of which includes a plurality of radially movable segments which define the circumference of said mandrel,
• each segment including a camming surface facing the transverse center plane of the drum,
• piston member encircling the central shaft and defining a camming surface on its outboard face, said camming surface on said piston member adapted to engage and apply a camming force substantially simultaneously against the camming surface of each of the segments of a respective one of said mandrels, said force urging said segments radially outwardly from said central shaft,
• first and second sleeves encircling said central shaft, said first sleeve receiving thereon said first mandrel and said first piston member, said second sleeve receiving thereon said second mandrel and said first piston member,
• a fluid-tight cavity disposed between said piston member and said sleeve adjacent the inboard side of each of said first and second mandrels, said cavities being connected in fluid flow communication with one another,
• first and second circular scroll plates encircling the central shaft at respective locations outward of each of said first and second mandrels, each scroll plate having defined in the inboard face thereof a plurality of slots, each of which is oriented non-radially with respect to said central shaft,
• first and second guide flanges interposed between respective ones of said first and second mandrels and said first and second scroll plates, each of said guide flanges including first and second pluralities of slots which are aligned radially of said central shaft, the slots of said first plurality of slots being blind slots and the slots of said second plurality of slots extending fully through the thickness of its respective guide flange,
• a rigid connector extending from each of said segments, through a respective one of said second slots of a respective one of said guide flanges, thence to engagement in a respective one of said non-radial slots defined in the inboard face of a respective one of said scroll plates, thereby constraining any material radial movement of any one of said segments of a given mandrel to substantially simultaneous and substantially equal radial movement of all the segments of the given mandrel.

Apparatus for converting a generally hollow cylindrical green tire carcass into a generally toroidal tire blank employing a shaping drum having a rotatable central shaft having a rotational axis and first and second mandrels mounted on the shaft, each of the mandrels being divided into a plurality of like segments constrained to radial movement relative to the rotational axis of the shaft and defining an outer circumference for the receipt thereon of a bead ring of the carcass when disposed on the shaping drum comprising

• first and second guide flanges, said first guide flange circumscribing and being rotationally fixed to the shaft in juxtaposition to said first mandrel and said second guide flange being rotationally fixed to said shaft in juxtaposition to said second mandrel,
• key means interposed between each of the segments of a respective mandrel and its associated guide flange, said key residing in respective radial slots defined in the faces of the mandrel and slidably residing in respective radial slots defined in a juxtaposed face of its associated guide flange whereby said segments of each mandrel are simultaneously rotatably driven by the shaft while simultaneously being radially positionable relative to the rotational axis of the shaft,
• each of said guide flanges including a plurality of throughbores disposed circumferentially about the outer margin thereof, and including first and second scroll rings, each of said scroll rings circumscribing and rotational with respect to the shaft and having respective faces facing inboard of the drum and juxtaposed to a respective one of said guide flanges, each scroll ring having defined a plurality of non-radially oriented slots accessible on that face thereof facing its respective guide flange, respective ones of said slots of said scroll ring being in register with respective ones of said throughbores of its respective guide flange, and rigid connector means having a first end anchored within a segment of a respective one of said mandrels and extending therefrom through a throughbore of said guide flange, thence with its opposite and second end engaging a respective one of said slots of a respective one of said scroll rings, thereby physically interconnecting each of said segments of a respective mandrel with a slot in a respective scroll ring to effect substantially simultaneous movement of each of the segments of the respective mandrel in a like direction and extent of movement of every other segment of the respective mandrel.