Blow molding devices

Blow molding devices for forming a blown plastic article from an elongated essentially tubular parison comprising;

• a sectional blow mold defining a cavity corresponding to the configuration of said blown plastic article, surfaces of said mold defining a bore for forming an article neck forming portion of said mold, said bore opening into the cavity of said mold, a rib on said bore defining surfaces for forming an inner annular rib in said neck portion of said article, a blow pin having a mandrel thereon and movable in said parison in said bore, an annular groove in said mandrel spacing portions of said mandrel, said spaced portions of said mandrel arranged to form spaced closures with respect to spaced areas of said bore forming surfaces of said mold, sections of said mold forming pinch-off areas and notches formed in said mold adjacent said rib on said bore defining surfaces and in said pinch-off areas for receiving material from said parison, one of said spaced portions of said mandrel arranged to move said material in said notches whereby grooves blown in the inner surface of the annular rib of said blown plastic article are filled by said material and smoothed by said spaced portion of said mandrel so as to form a continuously smooth innermost surface on said annular rib of said blown plastic article, means in said mandrel establishing communication between said annular groove and said blow pin so that air from said blow pin moves by way of said groove toward said parison between said closures.