Counter stretch connecting rod and positive fill level control rod
A mold device and a method related thereto for forming a plastic container from a preform. The mold device comprises a mold defining a mold cavity, an optional stretch initiation rod system for engaging an interior portion of the preform to define a stretch initiation area, and a centrally disposed pressure source positionable within the preform for introducing a pressurized fluid.
1. An apparatus for forming a plastic container from a preform, the preform having an upper portion with an opening, a body, and an internal volume accessible through the opening, the apparatus comprising:
a mold having a mold cavity for expanding the preform, the mold having an upper end, a lower end and a central portion extending from the upper end to the lower end about a longitudinal axis, the mold having a first aperture for accessing the mold cavity through the upper end, the first aperture being adapted for holding the preform at its upper portion while the body of the preform is placed into the central portion of the mold cavity;
a liquid supply means for supplying a pressurized liquid through the opening and into the internal volume of the preform; and
a centering rod disposed adjacent to the lower end of the mold and extendable along the longitudinal axis through the lower end into the mold cavity.
2. The apparatus for forming a plastic container from a preform according to claim 1 wherein the centering rod comprises a tip portion at its upper end, the tip portion being adapted to engage with an exterior feature disposed on the outer surface of the body of the preform.
3. The apparatus for forming a plastic container from a preform according to claim 2 wherein the tip portion of the centering rod comprises a protrusion, the protrusion being adapted to engage an indentation disposed on the outer surface of the body of the preform.
4. The apparatus for forming a plastic container from a preform according to claim 2 wherein the tip portion of the centering rod comprises an indentation, the indentation being adapted to engage a protrusion extending from the outer surface of the body of the preform.
5. The apparatus for forming a plastic container from a preform according to claim 1 wherein the centering rod is extendable between an extended position and a retracted position, wherein in the retracted position the centering rod does not extend into the central portion of the cavity.
6. The apparatus for forming a plastic container from a preform according to claim 1 wherein the centering rod is disposed below the lower end of the mold cavity, the centering rod is telescopically extendable into the central portion of the mold cavity through a second aperture in the lower end of the mold cavity.
7. The apparatus for forming a plastic container from a preform according to claim 1 wherein the centering rod is integrated into a bottom portion of the mold.
8. The apparatus for forming a plastic container from a preform according to claim 1 , further comprises a stretch rod being movable along the longitudinal direction through the first aperture and into the internal volume of the preform.
9. The apparatus for forming a plastic container from a preform according to claim 1 , wherein the centering rod is extendable through the lower end of the mold at a location opposite of the aperture into the mold cavity.