Patent ID: 7175797

Claim:
A manufacturing method of a weather strip, wherein said weather strip includes a molded member provided with a base bottom portion, and a seal portion, in which a hollow portion is formed, projects from said base bottom portion, and said weather strip is formed in a cavity of a molding device, which is provided with at least a core mold for forming said hollow portion, said core mold includes a center core having a center core body and a center extension plate extending from said center core body, and said core mold includes a side core having a pair of side core bodies adjacently provided at both sides of said center core in a longitudinal direction of said weather strip, and side extension plates extend from said side core bodies, said manufacturing method comprising the steps of: injecting an elastic material in a plasticized state being injected into the cavity, so that the cavity is filled with said elastic material; solidifying said elastic material, wherein at least three slits arranged in a longitudinal direction of said base bottom portion are formed on said base bottom portion, and bridge portions are formed between adjacent ones of said slits; removing said core mold from said slits to obtain said molded member in which said hollow portion is formed, wherein said slits includes a center slit from which said center core body is withdrawn, and a pair of side slits from which said side core bodies are withdrawn, wherein said center slit includes a first slit part having a length substantially equal to a length of center core body in the longitudinal direction of said weather strip and second slit parts extending in a direction such that the second slit parts intersect with the first slit part, said center core body is withdrawn from said center slit and thereafter said side core bodies are with drawn from said side slits, when said core mold is removed, said side extension plates are joined together with a connecting portion, and when said core mold is removed by sliding said side cores in an extending direction of said side extension plate, said side core bodies are separated relatively from said center core body, and said center core body is withdrawn from said hollow portion of said molded member each of said side slits includes: a main slit tart formed by said side extension plates, and extension slit parts provided so as to extend from ends of said main slit part in the longitudinal direction of said weather strip and formed by a mold part different from said side extension plates, and said mold part for forming the extension slit parts is separated relatively from said side core bodies at the same time that said center core body is separated relatively from said side core bodies and extracted when said molding device is opened.