Injection molding machine nozzle, includes annular piston operating in nozzle seat opening, with excellent guidance and sealing, mitigating against valve rod maloperation and breakage, whilst fostering high availability

摘要

Injection molding machine nozzle, includes annular piston operating in nozzle seat opening. The opening (not shown) of a seat for the nozzle is located in a section of the injection molding distributor, and accommodates the nozzle body, fixed vertically, its outlet tip (11) reaching the molding cavity. The nozzle casing is located between an internal surface of the seat opening and an outer surface of the nozzle body. The body includes a guide slot (7) in its upper end. An axial valve rod (9) guide passage extends through the nozzle, connecting slot and nozzle outlet. A rod guidance bush is inserted in the top of the guide passage. A valve system near the top of the body closes the nozzle outlet, to interrupt injection. The valve system comprises a piston casing in the seat opening; its inner surface contacting an outer surface (the interrupted flange) of the nozzle casing. A piston (6) is inserted to move in the seat opening, also fitting over the top of the nozzle body. A cylinder is thus defined by the seat opening, allowing vertical movement relative to the nozzle body. A transverse section (8) across the piston interior, operates the valve rod, as the piston rises or falls. The valve rod descends centrally from the transverse section, closing the nozzle. A cylinder cap (not shown) is inserted into the upper end of the seat opening, to prevent an unexpected (probably also importing undesirable) departure of the piston from the seat opening. Preferred features: The nozzle body includes high-conductivity components. These are incorporated, by making holes in nozzle blank material, and inserting high conductivity alloy into each of them, before shaping the nozzle material during manufacture.