Abstract: Apparatus is disclosed for filtering melted plastic used in an injection molding system. The apparatus consists of a housing having an inlet and outlet with a cylindrical inner chamber disposed in alignment therebetween, and a tubular filter element threadably mounted in the internal housing. To avoid loosening of the filter element, a plurality of spiral surfaces are formed in the filter element that are exposed to the pressurized flow of melted plastic, generating a resultant force that tends to screw the filter element tighter onto its threaded mount. The threaded mount is at the inlet end of the tubular element, causing it to extend in cantilever fashion axially into the internal chamber and toward the outlet. This creates an annular discharge passage around the filter element that is unobstructed, permitting the filtered plastic to converge smoothly into the outlet.

Abstract: The disclosure is directed to apparatus for filtering a flow of melted plastic prior to use in an injection molding machine. The apparatus includes a cylindrical filter screen disposed in a cylindrical chamber to define an inner inlet chamber and outer outlet chamber. The incoming plastic enters the interior of the filter screen through an axial passage formed in the screen side wall. The material is thereafter forced radially outward through small filtration openings formed through the screen side wall, leaving filtered material and contaminants at the inner wall. Purging or cleaning of the filter screen is effected by a reciprocating shaft that passes through the cylindrical filter screen and partly defines the inner chamber. The shaft carries an imperforate cylindrical sleeve which slides axially through the inner chamber, wiping the inner cylindrical surface of the filter screen as it goes.

Abstract: The disclosure is directed to dispersion apparatus for use with injection molding systems for thoroughly mixing hot melted plastic with coloring or other additives before injection into a mold. Dispersion is accomplished by passing the hot melted plastic through a chamber in which a plurality of smooth, spherical bodies are disposed. Each of the spherical bodies is formed with a plurality of peripheral grooves which are orthogonal and generally lie within planes passing through diameters of the body.

Abstract: Plastic injection molding apparatus consisting of two mold sections which define a mold cavity therebetween and are relatively movable to permit formation and removal of an article through the injection of hot melted plastic under high pressure. A plurality of coring pins are employed in conjunction with the mold sections to create voids of desired configuration in the molded article. Means are included to sense the pressure of the hot melted plastic as it enters the apparatus, and to actuate the coring pins into position within the mold cavity to create the desired voids. The coring pins also sense pressure within the mold cavity to achieve a balanced, self-adjusting operation.