Pin-in-sleeve device for in-article gas assisted injection molding

A pin-in-sleeve device for injecting a non-viscous fluid into a cavity of a mold, the mold including a socket for receiving the device, the socket having an open end which opens into the mold cavity, the device comprising:

• a sleeve which is received in the socket, the sleeve including:
• a longitudinally extending bore with an open first end, the bore having a first portion of a first diameter adjacent the bore open end, and a second portion of a second diameter, the second diameter being larger than the first diameter;
• a pin extending through the sleeve, a fluid flow path for the non-viscous fluid defined between the pin and the bore, the pin including:
• a forward section which is received in the bore first portion, and
• a base which is received in the bore second portion, the base having a diameter which is larger than the diameter of the bore first portion;
• a restraining member, connected with the sleeve for restraining the pin in the sleeve;
• and
• a filter which is received in the bore second portion rearward of the pin.

An apparatus for use in fluid assisted injection molding of plastic material so as to form an injection molded product, the apparatus comprising:

• a pair of mold members defining, when connected, a sealed cavity,
• a first opening provided in one of the mold members for admitting the plastic material into the cavity;
• a second opening provided in one of the mold members and spaced from the first opening for admitting a fluid into the cavity;
• a sleeve extending through the second opening, the sleeve having a longitudinally extending bore opening into the cavity, the bore having a first portion of a first diameter adjacent the cavity, and a second portion of a second diameter spaced from the cavity, the second diameter being larger than the first diameter, wherein the sleeve includes a portion spaced radially inwardly from a wall of the mold cavity, said portion including a means for keying into adjacent viscous fluid in the cavity;
• and,
• a pin extending through the sleeve, a fluid flow path defined between the pin and the bore, the pin including:
• a forward section which is received in the bore first portion, and
• a base which is received in the bore second portion, the base having a diameter which is larger than the diameter of the bore first portion.

An apparatus for use in fluid assisted injection molding of plastic material so as to form an injection molded product, the apparatus comprising:

• a pair of mold members defining, when connected, a sealed cavity,
• a first opening provided in one of the mold members for admitting the plastic material into the cavity;
• a second opening provided in one of the mold members and spaced from the first opening for admitting a fluid into the cavity;
• a sleeve extending through the second opening, the sleeve having a longitudinally extending bore opening into the cavity, the bore having a first portion of a first diameter adjacent the cavity, and a second portion of a second diameter spaced from the cavity, the second diameter being larger than the first diameter;
• a pin extending through the sleeve, a fluid flow path defined between the pin and the bore, the pin including:
• a forward section which is received in the bore first portion, and
• a base which is received in the bore second portion, the base having a diameter which is larger than the diameter of the bore first portion;
• and a filter which is received in the bore second portion.

A method of fluid assisted injection molding of plastic material so as to form an injection molded product, the method comprising:

• threadably connecting a pin-in-sleeve device to a socket in one of a pair of mold members, the pin-in-sleeve device including:
• a sleeve having a longitudinally extending bore with an open end, the bore having a first portion of a first diameter adjacent the bore open end, and a second portion of a second diameter spaced from the open end, the second diameter being larger than the first diameter;
• a pin extending through the sleeve, the pin including:
• a forward section which is received in the bore first portion, and
• a base which is received in the bore second portion, the base having a diameter which is larger than the diameter of the bore first portion;
• connecting the mold members together to form a sealed cavity which is defined by the mold members, such that the bore open end communicates with the cavity;
• injecting the plastic material through a nozzle into the sealed cavity;
• keying the sleeve to the plastic material at a location spaced radially inwardly from a wall of the sealed cavity;
• and,
• injecting a fluid through a fluid flow path defined between the pin and the bore.

A method of fluid assisted injection molding of plastic material so as to form an injection molded product, the method comprising:

• threadably connecting a pin-in-sleeve device to a socket in one of a pair of mold members, the pin-in-sleeve device including:
• a sleeve having a longitudinally extending bore with an open end, the bore having a first portion of a first diameter adjacent the bore open end, and a second portion of a second diameter spaced from the open end, the second diameter being larger than the first diameter;
• a pin extending through the sleeve, the pin including:
• a forward section which is received in the bore first portion, and
• a base which is received in the bore second portion, the base having a diameter which is larger than the diameter of the bore first portion;
• connecting the mold members together to form a sealed cavity which is defined by the mold members, such that the bore open end communicates with the cavity;
• injecting the plastic material through a nozzle into the sealed cavity;
• injecting a fluid through a fluid flow path defined between the pin and the bore;
• venting the injected fluid from the cavity through the fluid flow path;
• and,
• filtering the vented fluid of traces of plastic material with a filter located in the bore second portion.