초록 ▼

An injection molding system is used to mold a preform having an undercut. The molding system includes an injection core mold, and three injection cavity molds, which are a neck mold for defining a neck of the preform, a first cavity mold including two mold halves for defining an outer wall of the pr

An injection molding system is used to mold a preform having an undercut. The molding system includes an injection core mold, and three injection cavity molds, which are a neck mold for defining a neck of the preform, a first cavity mold including two mold halves for defining an outer wall of the preform having the undercut, and a second cavity mold for defining a remaining outer wall of the preform. The molding system also includes a clamping unit for opening and clamping the foregoing molds and a mold half opening mechanism for opening and clamping mold halves of the first cavity mold.

대표청구항 ▼

An injection molding system for making a preform with an undercut on an outer wall thereof, comprising: (a) a neck mold for defining an outer wall of a neck of the preform and for transferring the injection molded preform to a succeeding process after mold opening by holding a neck portion of the pr

An injection molding system for making a preform with an undercut on an outer wall thereof, comprising: (a) a neck mold for defining an outer wall of a neck of the preform and for transferring the injection molded preform to a succeeding process after mold opening by holding a neck portion of the preform (b) an injection core mold for defining an inner wall of the preform and to be moved axially of and relatively to the preform; (c) an injection cavity mold for defining an outer wall, except said neck portion, of the preform and to be moved axially of and relatively to the preform, said injection cavity mold including a first cavity mold having mold halves to be opened and clamped in the direction perpendicular to the axial direction of the preform, the cavities of said mold halves defining an outer wall of the preform having the undercut, and a second cavity mold having a cavity for defining another outer wall of the preform and to be opened axially of and relatively to the preform, said first cavity mold including a first annular taper at the lower end thereof, said second cavity mold including a recess surrounding said annular taper of said first cavity mold and having a second annular taper therein so that aid first and second annular tapers come into contact with each other when said molds are clamped; (d) a mold clamping unit for opening and clamping said injection core mold and said injection cavity mold by using a mold clamping force along the axial direction of the preform and an opening force reverse to the clamping force; and (e) a mold half opening mechanism for receiving the mold opening force from sad second cavity mold to guide said mold halves to a position where said first cavity mold is released in directions perpendicular to the axial direction of the preform from a largest diameter portion of the undercut of the preform as said second cavity mold is relatively opened in the axial direction of the preform at the initial stage of the mold opening process, and then to guide both said first and second cavity molds in the axial direction of the preform to open said first and second cavity molds.