Finish assembly for a plastic container or preform

Abstract

A finish assembly for a plastic container or preform includes a plastic neck having an open end surrounded by an external flange. The flange has an open axially facing channel adjacent to the outer surface of the neck. A plastic finish ring has an annular body, an inner surface opposed to the outer surface of the neck, an outer surface with at least one external thread, bead or other means for attachment of a closure, and an annular lip extending into the channel. The channel is formed in part by a radially inwardly extending conical surface on the flange, and the lip has a radially outwardly extending conical surface in facing engagement with the radially inwardly facing conical surface on the flange to seal the finish ring against the flange against entry of liquid between the finish ring and the neck.

1 . A method of making a preform assembly for blow molding a container, which includes the steps of: 
 (a) providing a plastic preform having a body with a closed end and a neck extending from said body, said neck having an open end and a radially outwardly extending flange surrounding said open end, said flange having an open axially facing channel adjacent to an outer surface of said neck,    (b) providing a finish ring having an annular body, an outer surface with at least one external means for securing a closure, and an annular lip extending axially from said body, and    (c) assembling said finish ring to said preform until said ring abuts said flange such that said ring is received over said outer surface of said neck and said annular lip is received in said channel to seal said finish ring against said flange.    
     
     
         2 . The method set forth in  claim 1  wherein said channel in said flange is formed in part by a radially inwardly and axially facing conical surface on said flange, and said lip has a radially outwardly and axially facing conical surface in facing engagement with said radially inwardly facing conical surface on said flange.  
     
     
         3 . The method set forth in  claim 2  wherein said flange has an axially facing surface disposed radially outwardly of said channel, and wherein said finish ring has an axially facing surface opposed to said axially facing surface on said flange and disposed radially outwardly of said lip.  
     
     
         4 . The method set forth in  claim 3  wherein said axially facing surfaces are spaced from each other following said step (c).  
     
     
         5 . The method set forth in  claim 3  wherein said axially facing surfaces are in abutment following said step (c).  
     
     
         6 . The method set forth in  claim 2  wherein said channel in said flange is formed in part by an axially facing surface between said conical surface and said outer surface of said neck, and wherein said lip on said finish ring has an axially facing surface within said conical surface on said ring and opposed to said axially facing surface on said flange.  
     
     
         7 . The method set forth in  claim 6  wherein said axially facing surface on said flange and said lip are in opposed abutment.  
     
     
         8 . The method set forth in  claim 1  wherein said finish ring is circumferentially continuous.  
     
     
         9 . The method set forth in  claim 1  wherein said step (a) is carried out by injection or compression molding.  
     
     
         10 . A finish assembly for a plastic container or preform, which includes: 
 a plastic neck having an open end surrounded by an external flange, said flange having an open axially facing channel adjacent to an outer surface of said neck, and    a plastic finish ring having an annular body, an inner surface opposed to said outer surface of said neck, an outer surface with means for attachment of a closure, and an annular lip extending into said channel to seal said finish ring against said flange.    
     
     
         11 . The finish assembly set forth in  claim 10  wherein said channel in said flange is formed in part by a radially inwardly and axially facing conical surface on said flange, and said lip has a radially outwardly and axially facing conical surface in facing engagement with said radially inwardly facing conical surface on said flange.  
     
     
         12 . The finish assembly set forth in  claim 11  wherein said flange has an axially facing surface disposed radially outwardly of said channel, and wherein said finish ring has an axially facing surface opposed to said axially facing surface on said flange and disposed radially outwardly of said lip.  
     
     
         13 . The finish assembly set forth in  claim 12  wherein said axially facing surfaces are spaced from each other.  
     
     
         14 . The finish assembly set forth in  claim 12  wherein said axially facing surfaces are in opposed abutment.  
     
     
         15 . The finish assembly set forth in  claim 11  wherein said channel in said flange is formed in part by an axially facing surface between said conical surface and said outer surface of said neck, and wherein said lip on said finish ring has an axially facing surface within said conical surface on said ring and opposed to said axially facing surface on said flange.  
     
     
         16 . The finish assembly set forth in  claim 15  wherein said axially facing surface on said flange and said lip are in opposed abutment.  
     
     
         17 . The finish assembly set forth in  claim 10  wherein said neck is cylindrical, and wherein said finish ring is a circumferentially continuous cylindrical ring.  
     
     
         18 . The finish assembly set forth in  claim 10  wherein said means includes at least one external thread.  
     
     
         19 . A preform assembly for blow molding to form a plastic container, which includes: 
 a plastic preform having a body with a closed end for blow molding to form a container, and a neck extending integrally from said body having an open end surrounded by a radially outwardly extending flange, said flange having an annular undercut forming an axially facing channel, and    a finish ring having an annular body externally surrounding said neck, an outer surface with at least one external thread, and an annular lip extending axially from said body into said channel in sealing engagement with said flange.    
     
     
         20 . The preform assembly set forth in  claim 19  wherein said channel in said flange is formed in part by a radially inwardly and axially facing conical surface on said flange, and said lip has a radially outwardly and axially facing conical surface in facing engagement with said radially inwardly facing conical surface on said flange.  
     
     
         21 . The preform assembly set forth in  claim 20  wherein said flange has an axially facing surface disposed radially outwardly of said channel, and wherein said finish ring has an axially facing surface opposed to said axially facing surface on said flange and disposed radially outwardly of said lip.  
     
     
         22 . The preform assembly set forth in  claim 21  wherein said axially facing surfaces are spaced from each other.  
     
     
         23 . The preform assembly set forth in  claim 21  wherein said axially facing surfaces are in opposed abutment.  
     
     
         24 . The preform assembly set forth in  claim 20  wherein said channel in said flange is formed in part by an axially facing surface between said conical surface and said outer surface of said neck, and wherein said lip on said finish ring has an axially facing surface within said conical surface on said ring and opposed to said axially facing surface on said flange.  
     
     
         25 . The preform assembly set forth in  claim 24  wherein said axially facing surface on said flange and said lip are in opposed abutment.  
     
     
         26 . The preform assembly set forth in  claim 19  wherein said finish ring is circumferentially continuous.  
     
     
         27 . The preform assembly set forth in  claim 19  wherein said neck is cylindrical, and wherein said finish ring is a circumferentially continuous cylindrical ring.