Patent ID: 6299816
Filing Date: 2001-10-09
Classification: B29C

Abstract:
A method of manufacturing a synthetic resin hollow member incorporating an intermediate element wherein after the intermediate element is disposed between a pair of synthetic resin-made half bodies, the half bodies are brought into abutment with each other and joined together at their abutting portions, whereby the synthetic resin hollow member incorporating the intermediate element is produced, the method comprising:using a pair of rotary injection molding dies which can be opened and closed relative to each other and are rotatable relative to each other at angular intervals of (360/6n) degrees, each die having a half body molding section consisting of at least one male molding portion and two female molding portions in a repetitive sequence of male/female/female in a direction of rotation for each rotational run over an angle of (360/3n) degrees, each die also having an intermediate element molding portion provided between specified half body molding portions in the direction of rotation for each rotational run over an angle of (360/3n) degrees, and wherein n is a natural number;a first die clamping step for closing and clamping the molding die pair;a first injection step for injecting a melted resin mass into a molding cavity defined by closing the pair of molding dies for molding a first half body and a second half body through a combination of male and female portions and for molding an intermediate element to be set between the half bodies through a combination of intermediate element molding portions;a first die rotating step for opening the pair of dies after the first injection step and causing the dies to rotate for an angle of (360/6n) degrees relative to each other so that the intermediate element is mated to and fitted in the first half body;a second die rotating step for opening the pair of dies again after the first die rotating step and causing the dies to rotate for a further angle of (360/6n) degrees relative to each other so that the first half body in which the intermediate element is set is mated to and brought into abutment with the second half body through a combination of female molding portions;a second die clamping step for closing and clamping the pair of dies again after the second die rotating step; anda second injection step for injecting a melted resin mass onto abutting portions of the half bodies for joining the two half bodies thereby forming the hollow member incorporating the intermdeiate element;whereby upon every two die rotating steps, a hollow member having the intermediate element set in place between the first and second half bodies can be obtained and wherein all steps in a series are performed using the same pair of molding dies.