Patent ID: 8286326

Claim:
A method of manufacturing an elongated core which is buried in an elongated trim made from a polymer material, the method comprising: a primary core preparatory step comprising a slit forming step and a rolling step to prepare a primary core in which core pieces and spaces are alternately provided in a longitudinal direction of the primary core, wherein the longitudinal direction of the primary core being a first direction and a width direction of the primary core being a second direction; wherein the slit forming step being performed by supplying an elongated strip-shaped metal plate to between a pair of slitter rollers engaged with each other, forming slits, which extend in the second direction in a state in which the slits are not formed to a portion of the strip-shaped metal plate in the second direction, at predetermined intervals in the first direction so as to form the core pieces between the adjacent slits; and wherein the rolling step being performed by supplying the strip-shaped metal plate having the slits formed therein to between a pair of rolling rollers, rolling the portion of the strip-shaped metal plate in which the slits are not formed in the second direction to form a rolled portion extending in the first direction, and expanding the slits in the first direction to form the spaces; and a deformed portion forming step being performed by supplying the primary core to between a pair of deformed portion forming rollers engaged with each other such that reinforcing deformed portions extending in the second direction are repetitively formed in the first direction.