Patent ID: 7147816

Claim:
A method for forming a resin hollow body by injection molding, comprising the steps of: a primary injection molding of forming a pair of primary semi-hollow bodies by injecting a molten resin into cavities defined by a slidable mold and a movable mold; butting open ends of the semi-hollow bodies at butt ends thereof so as to define a joining space on an outer periphery of the butt ends by sliding the slidable mold relative to the movable mold after the primary injection molding, and a secondary injection molding for uniting the primary semi-hollow bodies into a single body by injecting a molten resin so as to fill the joining space; wherein the movable mold is moved at a predetermined degree during the secondary injection molding to thereby fill a space between the butt ends with the molten resin, wherein the movable mold is moved at the predetermined degree by the filling pressure of the molten resin to fill the space between the butt ends.