Method for blow molding articles with deeply recessed edges

摘要

A method and apparatus for blow molding articles with deeply recessed edges utilizing mold halves each of which consists of a center section and end sections that are relatively movable in a direction lengthwise of the mold to enable both lengthening and shortening of the mold. Rack and pinion assemblies are associated with the mold sections so that in response to movement of one end section toward or away from the center section, the other end section is similarly moved toward or away from the center section to thereby enable selective lengthwise lengthening or shortening of the mold halves. This enables the mold halves to be shortened after they are closed on a parison to thereby compress the shape of the parison within the mold to thereby move portions of the parison closer to the edges of the mold cavity. This facilitates a uniform distribution of plastic material along the surface of the mold cavity when the parison is blown into conformity with the mold cavity.