Apparatus having an in-the-mold gas injection pin

An injection molding apparatus comprising:

• a pair of mold members defining, when closed, a sealed cavity;
• a means for supplying a pressurized viscous material;
• a first opening provided in one of said mold members for allowing the injection of the viscous material into said cavity;
• a second opening provided in one of said mold members, and spaced from said first opening;
• a probe located in said second opening and reciprocated therein from a first retracted position to a second extended position, said probe comprising:
• a first end, which selectively extends into said cavity when said probe is in said second position,
• a second end, and
• a longitudinally extending bore which terminates in a port adjacent said first end, said bore being selectively used, when said probe is in said second position, for the injection of a non-viscous fluid into said cavity and the subsequent venting of the fluid from the cavity;
• a means for supplying the non-viscous fluid to said probe bore, said means for supplying the non-viscous fluid including a first valve for selectively allowing a flow of the non-viscous fluid to said probe bore;
• a piston and cylinder construction for reciprocating said probe in said second opening in relation to said cavity;
• and,
• a sensor mounted on said cylinder for sensing when said piston is in a predetermined position, wherein said means for supplying the non-viscous fluid is activated only after said piston is in said predetermined position.

An apparatus for producing a fluid-assisted injection molded product of a viscous material, the apparatus comprising:

• a mold space;
• a means for supplying a pressurized viscous material;
• a first passage opening into said mold space, for introducing the viscous material into said mold space;
• a second passage opening into said mold space, and spaced from said first passage, for introducing a pressurized non-viscous fluid into the viscous material in said mold space so that a fluid cavity is formed in the viscous material;
• a probe extending into said second passage and reciprocated therein, said probe comprising:
• a first end including a port,
• a second end, and
• a longitudinally extending bore through which the non-viscous fluid is adapted to flow, said bore communicating with said port;
• a means for supplying the pressurized non-viscous fluid to said mold space through said longitudinally extending bore in said probe;
• a means for reciprocating said probe in said second passage wherein said means for reciprocating comprises:
• a cylinder having an end wall,
• a piston mounted for reciprocation in said cylinder,
• a piston rod extending from at least one side of said piston out through said end wall of said cylinder, said probe being secured to said piston rod, and
• a means for securing said cylinder end wall to a mold member which helps define said mold space;
• and,
• a programmable means for controlling said means for supplying said non-viscous fluid and said means for reciprocating.

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

• a pair of mold members defining, when closed, a sealed cavity;
• a means for supplying a pressurized plastic material;
• a first opening provided in one of said mold members for allowing the injection of the plastic material into said cavity;
• a means for supplying a pressurized gas;
• a second opening provided in one of said mold members, for allowing the injection of the pressurized gas into said cavity;
• a probe located in said second opening and reciprocated therein from a retracted position to an extended position, said probe comprising:
• a first end, adapted to selectively extend into said cavity,
• a second end, and
• a first longitudinally extending bore which terminates in a port located adjacent said first end, said bore being used to channel the gas into said cavity;
• a means for reciprocating said probe in relation to said cavity, wherein said means for reciprocating comprises:
• a cylinder,
• a piston mounted for reciprocation in said cylinder,
• a piston rod extending from at least one side of said piston, wherein said probe is secured to said piston rod,
• a second bore extending longitudinally in said piston rod and communicating with said first bore, and
• a fastener for securing said cylinder to one of said mold members;
• and,
• a control means for controlling the operation of said means for reciprocating and said means for supplying the gas.