INJECTION MOLDING APPARATUS

• Main Authors: AZUMA KEIJI, NAKADA MASAAKI, SHIMODA KAZUHIKO, KOBAYAKAWA MASUNORI
• Format: Patent
• Language: English
• Published: 23.06.1989
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; PERFORMING OPERATIONS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

PURPOSE:To improve the finishing accuracy of a product and enable the whole apparatus to be simplified in its construction and cheapened in cost by providing a recess portion wherein an exhaust means is arranged in communicating with at least one of the cavities of both die members and a specified piston moving in reciprocation within the recess portion. CONSTITUTION:When a die clamping operation is started through the rising of the low die member 37, a cylinder 41 goes up and fits the outer periphery of the piston 36. Although the piston 36 moves downwardly in the cylinder 41, it is stopped at a fixed place because a lock member 44 is faced to the inside of the cylinder 41. During the injection, the melted material 52 moves a lock releasing means 47 through the pressure and as a interlocking portion 48 moves downwardly, a rod 49a pushes the one end of the lock member 44 via the oil 51 in an oil conduit 50 and the lock member is withdrawn form the inside of the cylinder 41. With this manner, the lock to the piston 36 is released, so that the volume communicating to the cavity 39 within the cylinder 41 becomes large and the air or gas within the cavity 39 is forcibly brought out through an air vent 40 into the space.