Degassing apparatus for a metal mold

A degassing apparatus, incorporated with a molding apparatus having a mold cavity, which comprises:

• a spool having a bore formed therein, the spool further having formed therein a gas inlet opening adapted to be communicatively coupled to the mold cavity of the molding apparatus, and a gas outlet opening, the gas inlet and outlet openings being in selective communication and non-communication with each other;
• means for selectively controlling the communication and non-communication between the gas inlet and gas outlet openings;
• and
• a piston mounted in the bore and coupled to the communication controlling means, the piston being reciprocatingly slidable between a first position and a second position, the bore being further formed with first and second chambers situated on opposite axial sides of the piston;
• the spool further including first, second and third fluid ports formed therein, the first and second ports being in communication with the first and second chambers respectively;
• the piston further having formed therein a channel, the channel being in communication with the first chamber;
• the piston further including an annular groove formed in the periphery thereof, the annular groove being in communication with the channel and being in selective communication with the third port, wherein the third port and the first chamber are in communication and the gas inlet and outlet openings are in non-communication when the piston is in the first position, and wherein the third port and the first chamber are in non-communication and the gas inlet and outlet openings are in communication when the piston is in the second position.

A degassing apparatus incorporated with a molding apparatus having a mold cavity, which comprises:

• a spool having a bore formed therein, the spool further having formed therein a gas inlet opening adapted to be communicatively coupled to the mold cavity of the molding apparatus, and a gas outlet opening, the gas inlet and outlet openings being in selective communication and non-communication with each other;
• means for selectively controlling the communication and non-communication between the gas inlet and gas outlet openings;
• a piston mounted in the bore and coupled to the communication controlling means, the piston being reciprocatingly slidable between a first position and a second position, the bore being further formed with first and second chambers situated on opposite axial sides of the piston;
• and
• means operatively coacting on the piston for biasing the piston toward one of the first and second positions;
• the spool further including first, second and third fluid ports formed therein, the first and second ports being in communication with the first and second chambers respectively;
• the piston further having formed therein a channel, the channel being in communication with the third port, and being selectively in communication with one of the first chamber and the second chamber, the gas inlet and outlet openings being in non-communication when the piston is in the first position, and being in communication when the piston is in the second position.

In combination:

• (a) a degassing apparatus incorporated with a molding apparatus, the degassing apparatus including
• a spool having a bore formed therein, the spool further having formed therein a gas inlet opening adapted to be communicatively coupled to the mold cavity of the molding apparatus, and a gas outlet opening, the gas inlet and outlet openings being in selective communication and non-communication with each other;
• means for selectively controlling the communication and non-communication between the gas inlet and gas outlet openings;
• and
• a piston mounted in the bore and coupled to the communication controlling means, the piston being reciprocatingly slidable between a first position and a second position, the bore being further formed with first and second chambers situated on opposite axial sides of the piston;
• the spool further including first, second and third fluid ports formed therein, the first and second ports being in communication with the first and second chambers respectively;
• the piston further having formed therein a first channel interconnecting the first and second chamber, and a second channel interconnecting the third port and the first chamber when the piston is in the first position, wherein the gas inlet and outlet openings are in non-communication, the third port and the first chamber being in non-communication when the piston is in the second position, wherein the gas inlet and outlet openings are in communication;
• and
• (b) means for effecting movement of the piston between the first and second positions, the piston movement effecting means including means for selectively applying a pressurized fluid to at least one of the first, second and third ports.

A gas-venting arrangement incorporated with a mold including stationary and movable mold portions, together defining a mold cavity to be filled with a molten material, the gasventing arrangement comprising:

• (a) a degassing apparatus, the degassing apparatus including
• a spool, the spool having a first end portion adapted to be coupled to the molding apparatus, the first end portion of the spool having a gas inlet opening formed therein and adapted to be in communication with the mold cavity, and a gas exhaust hole formed therein, the spool having an inner bore formed therein:
• a valve guide member mounted on the spool, the valve guide member including a bore formed therethrough;
• a valve rod mounted on the valve guide member and reciprocatingly slidable within the valve guide bore, the valve rod having opposite axial ends;
• a valve body mounted on one axial end of the valve rod, the gas inlet opening defining a valve seat, the valve body being adapted to closely engage the valve seat and to form a gas tight seal therewith;
• a psiton mounted on the other axial end of the valve rod and closely received by the spool inner bore, the piston being reciprocatingly slidable within the inner bore, the piston having opposite first and second axial sides, the inner bore including first and second chambers situated on the first and second piston axial sides respectively, the piston further including a channel formed therein;
• interconnecting said first and second chambers
• the spool further having formed therein first, second and third fluid ports, the first and second ports being in communication with the first and second chambers respectively;
• the piston being selectively positionable in a first position, wherein the valve body closely engages the valve seat and the third port is in communication with the first chamber, and a second position, wherein the valve body is disengaged from the valve seat and the third port is in non-communication with the first chamber;
• (b) a gas vent groove communicating with the spool bore and formed in said mold to communicate with the mold cavity;
• and
• (c) at least one bypass conduit branched from the gas vent groove and selectively in communication with the gas exhaust hole, wherein the bypass conduit and the gas vent groove are in non-communication with the gas exhaust hole when the valve body closely engages the valve seat, and wherein the bypass conduit and the gas vent groove are in communication with the gas exhaust hole when the valve body is disengaged from the valve seat.

A degassing apparatus incorporated with a molding apparatus, the molding apparatus having a mold cavity into which a molten material is injected, the degassing apparatus comprising:

• a spool, the spool having a first end portion adapted to be coupled to the molding apparatus, the first end portion of the spool having a gas inlet opening formed therein and adapted to be in communication with the mold cavity, and a gas exhaust hole formed therein, the spool having an inner bore formed therein;
• a valve guide member mounted on the spool, the valve guide member including a bore formed therethrough;
• a valve rod mounted on the valve guide member and reciprocatingly slidable within the valve guide bore, the valve rod having opposite axial ends;
• a valve body mounted on one axial end of the valve rod, the gas inlet opening defining a valve seat, the valve body being adapted to closely engage the valve seat and to form a gas tight seal therein;
• and
• a piston mounted to the other axial end of the valve rod and closely received by the spool inner bore, the piston being reciprocatingly slidable within the inner bore, the piston having opposite first and second axial sides, the inner bore including first and second chambers situated on the first and second piston axial sides respectively, the piston further including a channel formed therein;
• interconnecting said first and second chambers;
• the spool further having formed therein first, second and third fluid ports, the first and second ports being in communication with the first and second chambers respectively;
• the piston being selectively positionable in a first position, wherein the valve body closely engages the valve seat and the third port is in communication with the first chamber, and a second position, wherein the valve body is disengaged from the valve seat and the third port is in non-communication with the first chamber.

A degassing apparatus incorporated with a molding apparatus having a mold cavity, which comprises:

• a spool having a bore formed therein, the spool further having formed therein a gas inlet opening adapted to be communicatively coupled to the mold cavity of the molding apparatus, and a gas outlet opening, the gas inlet and outlet openings being in selective communication and non-communication with each other;
• means for selectively controlling the communication and non-communication between the gas inlet and gas outlet openings;
• and
• a piston mounted in the bore and coupled to the communication controlling means, the piston being reciprocatingly slidable between a first position and a second position, the bore being further formed with first and second chambers situated on opposite axial sides of the piston;
• the spool further including first, second and third fluid ports formed therein, the first and second ports being in communication with the first and second chambers respectively;
• the spool further including an inner wall defining the periphery of the spool bore, the spool having an annular groove formed in the inner wall, the groove having substantially the same width as the axial length of the peripheral edge of the piston, the annular groove being in communication with the third port, wherein the third port communicates with the first chamber and the first port through the annular groove when the piston is in the second position, and wherein the third port communicates with the second chamber and the second port through the annular groove when the piston is in the first position.