초록 ▼

Apparatus and method are disclosed for closing and sealing a molded plastic article formed by expanding a heated plastic parison within a chamber or cavity defined by a plurality of mold sections. The article is closed and sealed by at least one movable sealing member which has a protruding pinch su

Apparatus and method are disclosed for closing and sealing a molded plastic article formed by expanding a heated plastic parison within a chamber or cavity defined by a plurality of mold sections. The article is closed and sealed by at least one movable sealing member which has a protruding pinch surface to weaken or sever the parison and recess surface portions selectively above or below the protruding pinch surface which provide plastic-receiving reservoirs that aid in the formation of an unobtrusive seal adjacent the surface of the article. The sealing member may also include parison engaging seat or heel portions which further aid in the sealing operation. The temperature of the mold sections adjacent the sealing operation is controlled to selectively retard the cooling of the parison, which is in direct contact with the cavity surface, to maintain the parison at a sufficiently elevated temperature to permit closing and sealing by the sealing member.

대표청구항 ▼

In a plastic molding apparatus comprising a plurality of mold sections closable to define a mold having an interior cavity of selected shape about a heated plastic parison and means for expanding said parison to conform to the shape of said interior cavity, opening means in said cavity through which

In a plastic molding apparatus comprising a plurality of mold sections closable to define a mold having an interior cavity of selected shape about a heated plastic parison and means for expanding said parison to conform to the shape of said interior cavity, opening means in said cavity through which said parison extends, the improvement comprising means for sealing said parison comprising a pair of sealing members including facing parison engaging surfaces on opposite sides of said parison and movable relative to said mold sections to engage said parison between said facing parison engaging surfaces, each of said parison engaging surfaces comprising a protruding surface portion with an elongated narrow pinch edge for pinching the parison together, and a recessed surface portion therebelow defining a plastic receiving reservoir, said interior cavity of said mold defining a generally planar surface adjacent said opening means through which said parison extends, said sealing members being movable to seal said parison therebetween in the area of said opening means whereby said recesses form a thickened seal portion substantially in the same plane as said planar surface.