Abstract: A hot runner system for injecting precise quantities of at least one resin advancing under pressure from a resin source wherein the system includes a shooting pot having a piston with opposed working surfaces which divide the shooting pot into at least two reservoirs. Resin under pressure is switched cyclically from one reservoir to the other whereby the piston is driven by resin under pressure to purge one reservoir while the other reservoir is loaded.

Abstract: A mold cavity, a molten plastic inlet conduit for communication therewith and a channel in the inlet conduit for conveying molten plastic to the mold cavity. Separate heating and cooling are provided in the inlet conduit adjacent the mold cavity to closely control the temperature of the molten plastic in the channel adjacent the mold cavity.

Abstract: Apparatus for forming multilayered articles including a nozzle communicating with the mold cavity. The nozzle includes a first nozzle channel for feeding a first thermoplastic material to the mold cavity and a second nozzle channel communicating with the first nozzle channel for feeding a second thermoplastic material to the mold cavity. A metered amount of second material is fed from the second nozzle channel to the first nozzle channel and subsequently to the mold cavity by the first material from the first nozzle channel.

Abstract: A metering device, a shooting pot, useful in the hot runner system of an injection molding machine including a piston cylinder assembly where the piston is movable in a first direction to effect a valve action and in a second direction to advance a metered volume of thermoplastic material.

Abstract: A stack mold apparatus for forming plastic articles is described. The apparatus includes an insulated runner system for delivering molten plastic material to the mold spaces for forming the parts. The apparatus further includes a mechanism for ejecting the solidified material of the runner when it becomes necessary to change the plastic material being used. In a first embodiment, the ejector mechanism has a pair of movable plates that form part of the central mold portion of the stack mold. In a second embodiment, the ejector mechanism has a movable plate, forming half of the central mold portion, having sucker pins and ejector bars incorporated therein.

Abstract: A plastic molding system and a method for delivering a melt stream of moldable plastic material to a mold cavity wherein a plastic melt is conveyed through a distribution channel and a mold channel or heated nozzle communicating with the distribution channel to the mold cavity via a mold gate between the mold channel and the mold cavity to fill the mold cavity. The plastic melt is frozen in the gate after the mold cavity is filled to block access from the mold channel to the mold cavity. A heated probe is provided in the mold channel movable from a first position spaced from the mold gate to provide a wide flow channel to the mold cavity to a second position adjacent the mold gate to melt the frozen plastic in the gate.

Abstract: Injection molding apparatus and process characterized by feeding a supply of thermoplastic material to a shooting pot from a supply of thermoplastic material by a hot runner system, delivering a first charge of thermoplastic material from the shooting pot to a mold cavity, and delivering a second charge of thermoplastic material from the shooting pot to the mold cavity.