Check Valve Lip Seal for an Injection Molding Machine

Abstract

A check valve for a molding machine. The check valve has a stem portion and a ring portion movable along said stem portion between a melt channel open position and a melt channel closed position. A groove is formed in a forward face of the ring portion. The groove, in operation, receives melt to force an outer circumferential portion of the ring in a radial direction to provide a seal between the ring portion and a wall in the machine.

1 . A check valve for a molding machine, said check valve having a stem portion and a ring portion movable along said stem portion between a melt channel open position and a melt channel closed position, a groove formed in a forward face of said ring portion, said groove, in operation, receiving melt to force an outer circumferential portion of said ring in a radial direction to provide a seal between said ring portion and a wall in said machine.  
     
     
         2 . A check valve as defined in  claim 1  wherein said groove is a V-shaped groove.  
     
     
         3 . A check valve as defined in  claim 1  wherein said groove is a V-shaped groove with one side of said V extending in a direction parallel to said wall to form said outer circumferential portion.  
     
     
         4 . A check valve as defined in  claim 1  wherein said groove is relatively shallow with respect to the length of said ring.  
     
     
         5 . A check valve for a molding machine, said check valve having a stem portion and a ring portion movable along said stem portion between a melt channel open position and a melt channel closed position, a groove formed in a forward face of said ring portion, said groove forming a relatively thin annular lip around said ring to create a thin flexible extension from said ring, said extension being flexed, in operation, by injection material to form a seal between said ring and a wall of an injection channel.  
     
     
         6 . A check valve as defined in  claim 5  wherein said groove is a V-shaped groove.  
     
     
         7 . A check valve as defined in  claim 5  wherein said groove is a V-shaped groove with one side of said V extending in a direction parallel to said wall to form said annular lip.  
     
     
         8 . A check valve as defined in  claim 5  wherein said groove is relatively shallow with respect to the length of said ring.