Injection plastic feeder

Claim 1

In an injection molding apparatus having a lower stationary die plate and a movable upper die plate for movement towards and away from said lower die plate, at least one die cavity provided within one of said die plates adjacent the parting line of the upper and lower die plates, said apparatus further including a source of plasticized material and means in the other die plate for receiving and storing said plasticized material for injection into said die cavity, the improvement comprising: a first passage extending horizontally through said other die plate, said passage being in open communication with said receiving and storing means, said first passage having heating means internal thereto; a second passage disposed at an angle to the first passage, said second passage extending through and confined within said other die plate in a direction transverse to the first passage and intersecting said first passage tangentially thereof, said second passage extending in a direction towards said cavity and terminating in an orifice at one end, and in a closure member at the other end, said second passage terminating in a conical end of constantly reduced diameter the end of which defines said orifice, said orifice being open to said cavity, said orifice further being flush with said cavity at all times, whereby said orifice is never spaced apart from said cavity; and an axially movable heated valve member disposed within said second passage for movement toward and away from said orifice; bias means disposed between said valve member and said closure member in said second passage to normally urge said valve member towards said orifice to close said orifice to prevent communication between said second passage and said die cavity; said valve member having means responsive to injection pressure at a predetermined magnitude exceeding the force of said bias means to thereby move said valve member away from said orifice to provide said die cavity with heated plasticized material from said storage means along said first passage into said second passage and through said orifice; said bias means being effective to immediately move said valve member to close said orifice upon a reduction of injection pressure below the predetermined force of said bias means, whereby all portions of the molded article are contained within the cavity; said first passage internal heating means including a cylindrical rod for axial extension therethrough; said cylindrical rod receiving an electrical heating element and having a diameter less than the internal diameter of said first passage to permit movement of plasticized material through said first passage whereby said plasticized material in said first passage is constantly maintained in fluidic condition by application of a current to said electrical heating element; said valve member and said closure member in said second passage being axially bored to receive an electrical heating element secured to said valve member and movable therewith to maintain said plasticized material within said second passage in fluidic condition upon application of current to said electrical heating element; said valve member having a conical end portion matching said conical end portion of said second passage; said conical end portion of said valve member terminating into a needle tip portion adapted for extension into said orifice when said valve member is in its closed position to close off said orifice.