Plastic and nonmetallic article shaping or treating: processes – Direct application of fluid pressure differential to... – Corrugating
Reexamination Certificate
1999-05-22
2001-08-07
Silbaugh, Jan H. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Direct application of fluid pressure differential to...
Corrugating
C264S540000, C425S525000, C222S530000
Reexamination Certificate
active
06270715
ABSTRACT:
BACKGROUND—FIELD OF INVENTION
The invention relates to technology associated with blow molding practices used for manufacturing plastic bottles and specifically, containers having an integral collapsible spout, formed into a portion of container body.
BACKGROUND—DESCRIPTION OF PRIOR ART
There are certain unique blow molding methods and techniques used during the manufacturing process to successfully produce a container with a functional, integrally molded collapsible spout. When the centerline of the integral collapsible spout is located off centerline of the containment body or if an integral gripping means is positioned next to said spout, parison flashing must occur on both sides of integral collapsible spout. In doing so, this stabilizes the internal material stresses associated with the thickened cross-sectional wall that is created from flashing along the mold line of the integral collapsible spout. Thus, equal symmetry is maintained and the integral collapsible spout can maintain stability when collapsed to the fully retracted position for filling and packaging needs. The pinch surfaces of the mold blocks have been modified to help reduce the thickened cross-sectional material along the flute profile of each self latching bellows section. This is further improved by relieving the pinch surfaces and increasing the depth of gutter flash pockets to help move excess material away from the mold parting line. Thereby, creating a more uniform wall thickness throughout the spout.
An alternate method is sometimes preferred when the integral collapsible spout is positioned centrally with the containment body, allowing the parison to be captive within the minor dimension of said spout and extend through the center of containment body during the blow molding process. Thus, when utilizing this method, flashing is eliminated from the plurality of self latching bellow sections comprising integral collapsible spout.
OBJECTS AND ADVANTAGES
Accordingly, several objects and advantages of the present invention implement certain blow molding techniques during the manufacturing process, coupled with modifications to specific areas of the mold block sections.
Generally, the blow molding process of the present invention comprises the steps of providing an elongated, tubular, formable plastic material, called a parison, between open mold blocks; subsequently moving said mold blocks together until said mold blocks seat, thus forming a mold parting line; entrapping said parison between the defined cavities in said mold blocks; and thereafter injecting pressurized air into the interior of said parison, inflating and forcing the parison to the confines of said defined cavities in said mold blocks, thereby forming the desired blow molded container.
More specifically, on containers and bottles having the centerline of said integral collapsible spout offset from centerline of containment body, said parison must be aligned and be positioned so that it encapsulates the outermost extremities of each collapsible, self latching bellows section. Hence, creating parison flashing on both sides of said spout. In doing so, material will be distributed evenly throughout the integral collapsible spout and symmetry will be maintained along the mold parting line. To improve material thickening in the mold parting line area of integral collapsible spout, the pinch surfaces associated with the flute profile in each self latching bellows section have been modified from general mold and tooling practices. Therefore, the cross-sectional wall of these pinch surfaces are steeper, taller and more narrow than normal. The outer base wall of these pinch surfaces terminate into the gutter flash pockets located on both sides of integral collapsible spout, of said mold blocks. The depth of the gutter flash pockets have also been increased to reduce material thickening, allowing a maximum amount of material to pull away from said mold parting line of integral collapsible spout.
However, on containers having said integral collapsible spout centrally positioned with the containment body, parison flashing can be eliminated from the self latching bellow sections. To achieve this, said parison is processed in a captive method within the minor dimension of the integral collapsible spout, and extends through the containment body, proximal to the centerline of integral collapsible spout and containment body, during said blow molding process. This blow molding technique provides the same results as producing parison flashing on both sides and also allows said integral collapsible spout to maintain stability when in the fully retracted position.
Still further objects and advantages of these methods will become apparent from a consideration of the ensuing description and accompanying drawings.
REFERENCES:
patent: 5133481 (1992-07-01), Mayfield
patent: 5292241 (1994-03-01), Fang et al.
patent: 5972277 (1999-10-01), Mayfield
Kilpatrick & Stockton LLP
McDowell Suzanne E
Silbaugh Jan H.
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