Flexible annular core used for the production of hollow toroidal rubber shells

A flexible annular core used for the production of hollow toroidal rubber shells comprising, a pair of bead portions and a flexible shell portion, each of said bead portions having beads which are looped in a circumferential direction of the core in an inextensible fashion, at least one reinforcing layer reinforced with cords inextensible in the lengthwise direction thereof and folded back so as to enclose the beads, said flexible shell portion being comprised of said reinforcing layer and elastomer layers covering both sides of the reinforcing layer and extending across a pair of the bead portions, said core being fixed at its bead portions to movable ring molds which can be moved to and fro and deformed by the movable ring molds so as to deform repeatedly the flexible shell portion in a reversible manner between a cylindrical shape at the largest distance of the movable ring molds and a toroidal shape at the shortest distance of the molds, said bead portions fixed to the movable ring molds being composed of said reinforcing layers adhered with each other and said reinforcing layer and said elastomer layer adhered with each other to form an integral body, and said flexible shell portion being composed of said reinforcing layers not adhered with each other and said reinforcing layer and said elastomer layer not adhered with each other.