초록 ▼

Valve gated multi-cavity injection molding apparatus for five layer molding having actuating mechanisms for reciprocating elongated valve members between four different positions. Each actuating mechanism has a front and a rear aligned cylinders, a first piston connected to the head of one of the va

Valve gated multi-cavity injection molding apparatus for five layer molding having actuating mechanisms for reciprocating elongated valve members between four different positions. Each actuating mechanism has a front and a rear aligned cylinders, a first piston connected to the head of one of the valve members in the front cylinder and second and third pistons in the rear cylinder. The third piston has a stem portion which extends forwardly through the second piston into the front cylinder. Hydraulic pressure from four hydraulic lines connected to each actuating mechanism reciprocates each elongated valve member between the different positions. In the first closed position, the front end of the valve member is seated in the gate. In the second position, the front end of the valve member is retracted sufficiently to allow an initial amount of PET to flow from an outer annular melt channel through the gate. Then the valve member is retracted further to a third position to allow simultaneous flow of the PET and a barrier material from an inner annular melt channel. Then the valve member is retracted to a fully open position which allows the simultaneous flow of PET from a central melt channel. When the cavity is almost filled, the valve member returns briefly to the second position for filling before returning to the closed position for ejection.

대표청구항 ▼

[ The embodiments of the invention in which an exclusive property or privilege is claimed is defined as follow:] [13.]13. A method of manufacturing a molded article from two different materials to form a five layer wall structure comprising the steps of:(a) providing a first source of a first molten

[ The embodiments of the invention in which an exclusive property or privilege is claimed is defined as follow:] [13.]13. A method of manufacturing a molded article from two different materials to form a five layer wall structure comprising the steps of:(a) providing a first source of a first molten material, and a second source of a second molten material,(b) providing separate heated manifolds for the first and second molten materials,(c) providing at least one injection nozzle in fluid communication with both manifolds having first and third melt channels for the first molten material and a second channel for the second molten material,(d) providing a valve gating device to control the flow of the two molten materials through the channels through the nozzle, and(e) injecting the first molten material into a mold cavity through the first melt channel, then sequentially injecting the second molten material through the second melt channel while the first molten material is being injected and then sequentially injecting the first molten material through the third melt channel while the molten material flows through the first and second melt channels to form in the cavity an article having three layers of a first material and two layers of a second material.