Anti-sticking preforms for blow molded articles

Abstract

A preform for a blow molded container provided a tubular body having inner and an outer surface having a first end open to the inner surface and a second closed end opposite to the first end. The relative dimensions of the ends being such that the closed end is receivable in the open end of a similar preform to nest therein. The open end is provided with a passageway to provide communication with the outside atmosphere to prevent formation of a vacuum and thereby enable disassembly of the nesting preforms.

What is claimed is:  
     
         1 . A preform for a blow molded container comprising: 
 a generally tubular body formed about a central axis and having inner and outer surfaces surrounding the axis;    a first end open to the inner surface;    a second closed end opposite to and spaced from the first end;    a wide portion of the tubular body adjacent the first end;    a narrow portion of the tubular body spaced from the second end;    the outer surface of the narrow portion having a radial dimension smaller than the radial dimension of the inner surface at the wide portion, wherein the improvement comprises: 
 at least one interruption in the inner surface at the wide portion and extending axially from the first open end toward the second end and protruding radially outwardly from the inner surface a sufficient amount to provide an air passageway between the outer surface of the narrow portion of a similar preform and the inner surface of the wide portion to prevent a similar preform from sticking within the wide portion by vacuum.  
   
     
     
         2 . A preform as defined in  claim 1 , wherein said interruption is in the form of a groove.  
     
     
         3 . A preform as defined in  claim 2  wherein said groove is formed to extend axially of said tubular body  
     
     
         4 . A preform as defined in  claim 3  wherein said grooves is formed in the inner surface of said tubular body.  
     
     
         5 . A preform as defined in  claim 1  wherein said interruption is in the number of more than one.  
     
     
         6 . A preform as defined in  claim 1  wherein said interruption is in the number of three.  
     
     
         7 . A preform as defined in  claim 1  wherein said interruption is in the form of a rib.  
     
     
         8 . A preform as defined in  claim 7  wherein said rib is formed to extend axially of said tubular body.  
     
     
         9 . A preform as defined in  claim 8  wherein said rib is formed in the inner surface of said tubular body.