Expandable bead molding ring for a tire mold

An expandable bead molding ring assembly for a tire mold in a mold press that is configured to mold a green tire comprising a tread, two beads, and two sidewalls extending between the beads and the tread;

• the expandable bead molding ring assembly characterized by:
• a first annulus that is a segmented bead molding ring, comprising a plurality of segments that radially expand to form a circumferentially continuous radially outward-facing surface for molding one of the beads, and a radially inner frustraconical cam surface for dividing axially-directed forces into a radial force component and an axial force component;
• a second annulus, concentric and axially adjacent to the first annulus, that is a top spring plate, comprising radially-oriented radial springs that are attached to all of the plurality of segments for controlling radial movement of the plurality of segments;
• and
• a third annulus, concentric and axially adjacent to the second annulus, that is a bottom spring plate, comprising axially-oriented axial springs acting between the second annulus and the third annulus for controlling axial movement of the plurality of segments.

A mold for a green tire comprising a tread, two beads each having a radially inward-facing bead base extending from an axially outer heel to an axially inner toe, and two sidewalls extending between the beads and the tread;

• the mold comprising:
• first and second sidewall plates for molding, respectively, an outer surface of each of the sidewalls plus an axially outer portion of each of the beads approximately in to the heel;
• first and second bead molding rings for molding at least the bead bases of the two beads;
• and
• an inflatable vulcanizing membrane for molding the inside surfaces of the tire;
• wherein the mold is characterized by:
• at least one segmented bead molding ring that is annular and comprises a plurality of segments that radially expand to form a circumferentially continuous radially outward-facing surface for molding one of the beads in cooperation with one of the sidewall plates and the vulcanizing membrane;
• and a radially inner frustraconical cam surface for dividing axially-directed forces into a radial force component and an axial force component;
• an annular top spring plate, concentric and axially adjacent to the segmented bead molding ring, comprising radially-oriented radial springs that are attached to all of the plurality of segments for controlling radial movement of the plurality of segments;
• an annular bottom spring plate, concentric and axially adjacent to the top spring plate, comprising axially-oriented axial springs acting between the top spring plate and the bottom spring plate for controlling axial movement of the plurality of segments;
• and
• an annular lock ring having a frustraconical radially outer cam surface that is complementary to the radially inner cam surface of the first annulus, wherein:
• the lock ring is attached to the mold press such that the mold press will impart axially directed movement and axially directed forces to the lock ring;
• and
• the radially outer cam surface of the lock ring is positioned concentrically radially within the segmented bead molding ring such that the radially outer cam surface of the lock ring bears on the radially inner cam surface of the segmented bead molding ring for applying the axially directed forces from the mold press to the cam surface of the segmented bead molding ring.