Patent ID: 7850895

Claim:
A method for connecting and disconnecting an injection molding machine to and from a shutoff assembly, comprising the steps of: connecting the injection molding machine to the mold, the step of connecting including the substeps of: mating a nozzle of the injection molding machine to a seat in an exterior wall of a chamber of a shutoff assembly, the seat in fluid communication with the chamber through a first opening extending from the exterior wall to an interior entry wall of the chamber, the interior entry wall having a first sealing surface around the first opening; advancing an elongate stem of the nozzle through the first opening into the chamber; flowing molten polymer through the first opening, to a second opening in an interior exit wall of the chamber and thence to at least one mold or sprue bar in fluid communication with the second opening; decompressing the mold, said step of decompressing comprising the substeps of: preventing a movable body disposed in the chamber from reaching a rear position, in which a second sealing surface of the movable body seals to the first sealing surface, by maintaining the movable body in a forward position with the elongate stem, in which the second sealing surface of the movable body is spaced from the first sealing surface; and allowing molten polymer to flow in the direction from the second opening to the first opening; disconnecting the injection molding machine from the assembly, said step of disconnecting including the substeps of: withdrawing the stem of the nozzle from the chamber through the first opening; allowing molten polymer downstream of the movable body to push the second sealing surface of the movable body into sealing engagement with the first sealing surface of the interior entry wall; and disconnecting the nozzle from the seat in the exterior wall of the chamber of the shutoff assembly.