# US 7,407,380 B2 · Valve pin bushing with vent channels for an injection molding apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,407,380 B2 - Document ID: US7407380B2 - Status: Granted - Kind: B2 - Application number: 11/347,137 - Filed: 2006-02-03 - Published: 2006-08-10 - Granted: 2008-08-05 - Earliest claimed: 2005-02-04 - Assignees: Mold-Masters (2007) Limited - Inventors: Payman Tabassi - Web page: https://patentgrep.com/patent/US7407380B2 ## CPC - B29C 45/2806: {consisting of needle valve systems (B29C45/2896 takes precedence)} - B29C 2045/2889: {Sealing guide bushings therefor} - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) ## Abstract An injection molding apparatus includes a manifold having a manifold channel for receiving a melt stream from a source. A nozzle having a nozzle channel receives the melt stream from the manifold channel and delivers the melt stream to a mold cavity through a mold gate. A valve pin bushing is provided between the manifold and the nozzle and includes a bore for receiving a valve pin. A chamber is provided in said valve pin bushing and communicates with the bore. An inlet channel extends between an inlet, which is located in an outer surface of the valve pin bushing, and the chamber. A vent channel extends between the chamber and an outlet, which is located in the outer surface of the valve pin bushing. A forced fluid source communicates with the inlet channel to force fluid through the inlet channel, said chamber and the vent channel. ## Claims ### Claim 1 An injection molding apparatus comprising: a manifold for receiving a melt stream from a source; a nozzle having a nozzle channel for receiving the melt stream from said manifold; a mold cavity in communication with said nozzle channel for receiving melt through a mold gate; a valve pin extending through said nozzle channel for selectively opening said mold gate; a valve pin bushing provided between said manifold and said nozzle, said valve pin bushing having a bore for slidably receiving said valve pin; a chamber provided in said valve pin bushing, said chamber being in communication with said valve pin bore; an inlet channel provided in said valve pin bushing, said inlet channel extending between an inlet located in an outer surface of said valve pin bushing and said chamber; and a vent channel provided in said valve pin bushing, said vent channel extending between said chamber and an outlet located in said outer surface of said valve pin bushing. ### Claim 2 (depends on 1) The injection molding apparatus of claim 1 further comprising: a forced fluid source in communication with said valve pin bushing inlet channel to force fluid through said inlet channel, said chamber and said vent channel. ### Claim 3 (depends on 2) The injection molding apparatus of claim 2, wherein said forced fluid source is a forced air source. ### Claim 4 (depends on 3) The injection molding apparatus of claim 3, wherein said inlet channel, said vent channel, and said forced air source provide a continuous forced air circuit. ### Claim 5 (depends on 4) The injection molding apparatus of claim 4, wherein a filter is located between said vent channel and said forced air source to remove foreign particles from the air. ### Claim 6 (depends on 5) The injection molding apparatus of claim 5, wherein said forced air circuit further includes a pressure sensor for indicating a blockage in said forced air circuit. ### Claim 7 (depends on 3) The injection molding apparatus of claim 3, further comprising: a first pipe extending between said forced air source and said valve pin bushing inlet channel; and a second pipe extending between said valve pin bushing vent channel and said forced air source, said filter being provided in said second pipe. ### Claim 8 (depends on 7) The injection molding apparatus of claim 7, wherein said pressure sensor is located in said first pipe. ### Claim 9 (depends on 4) The injection molding apparatus of claim 4, wherein said forced air circuit further includes a temperature sensor. ### Claim 10 (depends on 1) The injection molding apparatus of claim 1, wherein melt is located in said chamber of said valve pin bushing. ### Claim 11 (depends on 10) The injection molding apparatus of claim 10, wherein said chamber is a groove in a wall of said valve pin bushing bore. ### Claim 12 (depends on 3) The injection molding apparatus of claim 3, wherein said forced air source clears said valve pin bushing inlet channel, chamber and vent channel of gases escaping from the melt stream. ### Claim 13 An injection molding apparatus comprising: a manifold for receiving a melt stream from a source; a nozzle having a nozzle channel for receiving the melt stream from said manifold; a mold cavity in communication with said nozzle channel for receiving melt through a mold gate; a valve pin extending through said nozzle channel for selectively opening said mold gate; a valve pin bushing provided on an opposite side of said manifold from said nozzle, said valve pin bushing having a bore for slidably receiving said valve pin; a chamber provided in said valve pin bushing, said chamber being in communication with said valve pin bore; a first channel provided in said valve pin bushing, said first channel extending between an outer surface of said valve pin bushing and said chamber; a second channel provided in said valve pin bushing, said second channel extending between said chamber and said outer surface of said valve pin bushing; and a forced fluid source in communication with said first channel of said valve pin bushing to force fluid through said first channel, said chamber, and said second channel. ### Claim 14 (depends on 13) The injection molding apparatus of claim 13, wherein said forced fluid source is a forced air source. ### Claim 15 (depends on 13) The injection molding apparatus of claim 13, wherein said first channel, said second channel, and said forced fluid source provide a continuous forced fluid circuit. ### Claim 16 (depends on 15) The injection molding apparatus of claim 15, wherein a filter is located between said second channel and said forced fluid source to remove foreign particles from the fluid. ### Claim 17 (depends on 15) The injection molding apparatus of claim 15, wherein said forced fluid circuit further includes a temperature sensor. ### Claim 18 (depends on 13) The injection molding apparatus of claim 13, further comprising: a pressure sensor for indicating a blockage in said valve pin bushing. ### Claim 19 (depends on 13) The injection molding apparatus of claim 13, further comprising: a first pipe extending between said forced fluid source and said first channel of said valve pin bushing; and a second pipe extending between said second channel of said valve pin bushing and said forced fluid source. ### Claim 20 (depends on 19) The injection molding apparatus of claim 19, wherein a pressure sensor is located in said first pipe. ### Claim 21 (depends on 19) The injection molding apparatus of claim 19, wherein a filter is located in said second pipe. ### Claim 22 (depends on 13) The injection molding apparatus of claim 13, wherein said chamber is a groove in a wall of said bore of said valve pin bushing. ### Claim 23 (depends on 13) The injection molding apparatus of claim 13, wherein said forced fluid source clears said first channel, said chamber, and said second channel of gases escaping from the melt stream. ### Claim 24 (depends on 13) The injection molding apparatus of claim 13, wherein said valve pin bushing is positioned between said manifold and a back plate. ### Claim 25 (depends on 13) The injection molding apparatus of claim 13, further comprising: a filter coupled to an outlet of said second channel. ### Claim 26 (depends on 13) The injection molding apparatus of claim 13, wherein the locations of said first channel and said second channel allow fluid to be forced through said chamber tangential to said valve pin. ### Claim 27 (depends on 1) The injection molding apparatus of claim 1, further comprising: a filter coupled to the outlet of said vent channel.