Apparatus and method for forming hollow parisons of variable wall thickness

A parison forming device, comprising a means defining an orifice creating an outer circumferential perimeter of an annular opening, a mandrel assembly concentric to said orifice, creating an inner circumferential perimeter of an annular opening, and at least one radially displaceable slide, equipped with at least one individual actuator situated within said mandrel assembly, defining at least a portion of the inner circumferential perimeter of said annular opening, attached to said mandrel assembly, wherein said slide moves radially along radial confines situated within said mandrel assembly and said radial slide's position is established by said actuator situated within said mandrel assembly.

A parison forming device, comprising a means defining an orifice creating an outer circumferential perimeter of an annular opening, a mandrel assembly concentric to said orifice, creating an inner circumferential perimeter of said annular opening, and at least one radially displaceable slide, equipped with at least one individual actuator, defining said inner circumferential perimeter of said annular opening attached to said mandrel assembly, wherein said slide moves radially along radial confines situated within said mandrel assembly and said slide's radial position is established by said actuator situated within said mandrel assembly, and means to meter said annular opening by radial displacement of said slide relative to its initial position during the formation of the parison.

A parison forming device, comprising a means defining an orifice creating an outer circumferential perimeter of an annular opening, a mandrel assembly concentric to said orifice, creating an inner circumferential perimeter of an annular opening, and at least one radially displaceable slide, equipped with at least one individual actuator situated within said mandrel assembly, defining at least a portion of said inner circumferential perimeter of said annular opening attached to said mandrel assembly, wherein said slide moves radially along radial confines situated within said mandrel assembly and said slide's radial position is established by said actuator, and means to meter said annular opening by radial displacement of said slide relative to its initial position during te formation of the parison.

A method for the formation of a cylindrical parison of variable wall thickness, comprising the steps of extruding a hollow parison, and varying a circumferential wall thickness at selected locations about an inner circumference of said parison via movement of at least one radially displaceable slide, equipped with at least one individual actuator, in contact with an interior surface of said extruding parison, wherein said slide moves radially along radial confines situated within a mandrel assembly, and movement of said slide's radial position responds to movement of said actuator located within the periphery of the inner surface of said slide.

A method for the formation of a parison of variable wall thickness, comprising the steps of extruding the hollow parison, varying the circumferential wall thickness at selected locations about the inner circumference of said parison by a movement of at least one radially displaceable slide, equipped with at least one individual actuator, in contact with the interior surface of said extruding parison, wherein said slide moves radially along radial confines situate within a mandrel assembly and movement of said slide's radial position responds to movement of said actuator located within the periphery of the inner surface, and varying the wall thickness at selected locations along the longitudinal axis of said parison during the extrusion process by a movement of said slide.