Abstract: An injection molding shutoff assembly includes a chamber containing a movable body that is biased to a rear position in the chamber by a magnet in the movable body. In the rear position, the movable body provides a seal and prevents flow of molten plastic through the assembly. When the movable body is in a forward position, one or more passages permit flow of the molten plastic around the movable body and to an exit in the chamber, leading to one or more molds. An injection molding machine nozzle tip has a beveled front end which, when in an engaged position, seals with an exterior seat of the assembly block defining the chamber and protrudes into the chamber to prop the movable body to the forward position. A portion of the assembly block proximate the opening for the nozzle tip is made of ferromagnetic material, while the rest is not.

Abstract: A valve gate assembly comprises a piston that is actuable between a forward position and a rear position and has a piston stop surface and a forward pressure surface. A cylinder has a cylinder stop surface that is disposed to contact the piston stop surface when the piston is in the forward position. The cylinder stop surface is radially outward of at least a portion of the forward pressure surface and a shutoff pin is substantially aligned with the axis.

Abstract: A valve gate assembly comprises a piston that is actuable between a forward position and a rear position and has a piston stop surface and a forward pressure surface. A cylinder has a cylinder stop surface that is disposed to contact the piston stop surface when the piston is in the forward position. The cylinder stop surface is radially outward of at least a portion of the forward pressure surface and a shutoff pin is substantially aligned with the axis.

Abstract: An injection molding shutoff assembly includes a chamber containing a movable body that is biased to a rear position in the chamber by a magnet in the movable body. In the rear position, the movable body provides a seal and prevents flow of molten plastic through the assembly. When the movable body is in a forward position, one or more passages permit flow of the molten plastic around the movable body and to an exit in the chamber, leading to one or more molds. An injection molding machine nozzle tip has a beveled front end which, when in an engaged position, seals with an exterior seat of the assembly block defining the chamber and protrudes into the chamber to prop the movable body to the forward position. A portion of the assembly block proximate the opening for the nozzle tip is made of ferromagnetic material, while the rest is not.

Abstract: A valve gate assembly comprises a piston that is actuable between a forward position and a rear position and has a piston stop surface and a forward pressure surface. A cylinder has a cylinder stop surface that is disposed to contact the piston stop surface when the piston is in the forward position. The cylinder stop surface is radially outward of at least a portion of the forward pressure surface and a shutoff pin is substantially aligned with the axis.

Abstract: An injection molding filtration apparatus having a filter, a decompression passage, and a filter check valve is used to filter molten polymer, while allowing for more complete decompression of the equipment downstream from the filter. The filter check valve and decompression passage are preferably internal to the filter element itself. In alternative embodiments, the decompression passage may be a separate bypass line that is arranged in a parallel configuration with an oppositely directed bypass check valve. Preferably, each of the check valves uses the molten polymer to push a movable body into a sealing engagement with an internal wall of the valve.

Abstract: A valve gate assembly comprises a piston that is actuable between a forward position and a rear position and has a piston stop surface and a forward pressure surface. A cylinder has a cylinder stop surface that is disposed to contact the piston stop surface when the piston is in the forward position. The cylinder stop surface is radially outward of at least a portion of the forward pressure surface and a shutoff pin is substantially aligned with the axis.

Abstract: A valve gate assembly comprises a piston that is actuable between a forward position and a rear position and has a piston stop surface and a forward pressure surface. A cylinder has a cylinder stop surface that is disposed to contact the piston stop surface when the piston is in the forward position. The cylinder stop surface is radially outward of at least a portion of the forward pressure surface and a shutoff pin is substantially aligned with the axis.

Abstract: A method for connecting and disconnecting an injection molding machine to and from a shutoff assembly includes the steps of mating a nozzle of the injection molding machine to a seat in an exterior wall of a chamber of the shutoff assembly, advancing an elongate stem through a first opening into the chamber, and flowing molten polymer into the chamber and out a second opening in the chamber and on to a mold or sprue bar. The mold may be decompressed by maintaining a movable body disposed in the chamber in a forward position with the elongate stem and allowing the molten polymer to flow out the first opening. The injection molding machine may be disconnected from the shutoff assembly by withdrawing the stem of the nozzle from the chamber through the first opening, allowing molten polymer downstream of the movable body to push the movable body into engagement with a sealing surface of a interior entry wall of the chamber, and disconnecting the nozzle from the seat.

Abstract: An injection molding shutoff assembly that includes a chamber containing a movable body movable between rear and forward positions. In the rear position, the movable body provides a seal and prevents flow of molten plastic out the chamber inlet, called drool. When the movable body is in the forward position, one or more passages permit flow of the molten plastic around the movable body and to an exit in the chamber, leading to one or more molds. In an alternate embodiment, the apparatus also includes an elongate stem that maintains the movable body in the forward position allowing the injection molding system to decompress, thereby eliminating drool and decreasing downtime.

Abstract: A method for connecting and disconnecting an injection molding machine to and from a shutoff assembly includes the steps of mating a nozzle of the injection molding machine to a seat in an exterior wall of a chamber of the shutoff assembly, advancing an elongate stem through a first opening into the chamber, and flowing molten polymer into the chamber and out a second opening in the chamber and on to a mold or sprue bar. The mold may be decompressed by maintaining a movable body disposed in the chamber in a forward position with the elongate stem and allowing the molten polymer to flow out the first opening. The injection molding machine may be disconnected from the shutoff assembly by withdrawing the stem of the nozzle from the chamber through the first opening, allowing molten polymer downstream of the movable body to push the movable body into engagement with a sealing surface of a interior entry wall of the chamber, and disconnecting the nozzle from the seat.

Abstract: An injection molding shutoff assembly that includes a chamber containing a movable body movable between rear and forward positions. In the rear position, the movable body provides a seal and prevents flow of molten plastic out the chamber inlet, called drool. When the movable body is in the forward position, one or more passages permit flow of the molten plastic around the movable body and to an exit in the chamber, leading to one or more molds. In an alternate embodiment, the apparatus also includes an elongate stem that maintains the movable body in the forward position allowing the injection molding system to decompress, thereby eliminating drool and decreasing downtime.

Abstract: An injection molding nozzle assembly is disclosed comprising a one-piece central body having a generally-cylindrical first section defining a radial surface and terminating in a face and a generally-cylindrical second section defining a radial surface extending in axial alignment with the first section in a direction opposite to the face. A central passage extends axially within the second section, and one or more flow passages extend between the central passage and the face of the first section. At least one of the flow passages has an aperture in the radial surface of the second section which receives a plug. A nozzle seal is removably secured to each of the flow passages on the face of the first cylindrical section. A flange is provided that has a generally-cylindrical central opening that is to be received by the second cylindrical portion of the body and is affixed to the body so as to overlie each plug.

Abstract: An internally heated injection molding nozzle has a unitary head portion and body portion. The nozzle has opposed, generally planar, lateral faces and front and back sides. A melt passageway is defined by a bore extending through the head portion and body portion, and a heater core is received in an elongated cavity that is in generally parallel alignment with, and spaced from, the melt passageway.

Abstract: An injection molding nozzle assembly is disclosed comprising a one-piece central body having a generally-cylindrical first section defining a radial surface and terminating in a face and a generally-cylindrical second section defining a radial surface extending in axial alignment with the first section in a direction opposite to the face. A central passage extends axially within the second section, and one or more flow passages extend between the central passage and the face of the first section. At least one of the flow passages has an aperture in the radial surface of the second section which receives a plug. A nozzle seal is removably secured to each of the flow passages on the face of the first cylindrical section. A flange is provided that has a generally-cylindrical central opening that is to be received by the second cylindrical portion of the body and is affixed to the body so as to overlie each plug.

Abstract: An injection molding nozzle is disclosed in which the body has a front end and a central bore terminating at the front end, the front end receiving a needle assembly. The needle assembly has an outer retaining piece adapted to be removeably secured to the front end of the body. The inner piece of the needle assembly is adapted to be received within the outer retaining piece and includes a gating needle that extends through the central opening of the outer retaining piece so as to be in close proximity to the gate of the mold cavity. One or more spacers are provided that are selectively positioned between the inner piece and a shoulder in the front end of the body and a shoulder in the outer retaining piece, thus permitting adjustable axial positioning of the gating needle with respect to the central opening of the outer retaining piece.

Abstract: A valve pin adjustment system is provided for use in valve gated injection molding applications which enables adjustments to the positioning of the valve pin without necessitating removal of the clamping plates and valve assembly components, including valve pins. A piston associated with the valve pin includes a cylindrical body having first and second co-axially aligned internally threaded bores of respective first and second diameters. Preferably, the threads formed in the first and second bores are of the opposite hand. First and second externally-threaded cylindrical valve pin positioning members are respectively received in the first and second bores. Each of the positioning members includes a head portion and a tip portion. The tip of the second positioning member is in contact with the head of the first positioning member to lock the first positioning member in place, and the tip of the first positioning member is in contact with a head portion on the valve pin to locate the valve pin.

Abstract: An injection molding nozzle is disclosed in which the body has a front end and a central bore terminating at the front end, the front end receiving a needle assembly. The needle assembly has an outer retaining piece adapted to be removeably secured to the front end of the body. The inner piece of the needle assembly is adapted to be received within the outer retaining piece and includes a gating needle that extends through the central opening of the outer retaining piece so as to be in close proximity to the gate of the mold cavity. In one aspect of the invention, the gating needle has a central cylindrical portion with an outer surface that is spaced from the outer retaining piece and at least one melt passageway whose exit is located asymmetrically with respect to the longitudinal axis of the gating needle. In a second aspect, the melt passageway extends linearly and asymmetrically through the gating needle.

Abstract: An injection molding nozzle is disclosed in which the body has a front end and a central bore terminating at the front end, the front end receiving a needle assembly. The needle assembly has an outer retaining piece adapted to be removeably secured to the front end of the body. The inner piece of the needle assembly is adapted to be received within the outer retaining piece and includes a gating needle that extends through the central opening of the outer retaining piece so as to be in close proximity to the gate of the mold cavity. One or more spacers are provided that are selectively positioned between the inner piece and a shoulder in the front end of the body and a shoulder in the outer retaining piece, thus permitting adjustable axial positioning of the gating needle with respect to the central opening of the outer retaining piece.

Abstract: The valve pin adjustment system is provided for use in valve gated injection molding applications which enables adjustments to the positioning of the valve pin without necessitating removal of the clamping plates and valve assembly components, including valve pins. A piston associated with the valve pin includes a cylindrical body having first and second co-axially aligned internally threaded bores of respective first and second diameters. Preferably, the threads formed in the first and second bores are of the opposite hand. First and second externally-threaded cylindrical valve pin positioning members are respectively received in the first and second bores. Each of the positioning members includes a head portion and a tip portion. The tip of the second positioning member is in contact with the head of the first positioning member to lock the first positioning member in place, and the tip of the first positioning member is in contact with a head portion on the valve pin to locate the valve pin.