Non-Round container blow molding apparatus
AssigneeElectra Form, Inc.
InventorsDavid C. Oas, Carl L. Knepper, David P. Meiring, Timothy L. Bright
Life of this patent
Estimating the term…
Abstract
Method and apparatus for forming stretch blow molded containers having uniform sidewall thickness from physical symmetric parisons. Parisons are heated non-uniformly by rotating at a non-uniform rate in a heating station. A sensor determines the angular orientation of the parisons emerging from the heating station. Each parison is angularly reoriented at a repositioning station prior to introduction into a stretch blow molding station having non-round interior surfaces, so that the temperature profile of each parison corresponds with differential expansion required to form the desired non-round container.
Claims12
Apparatus for blow molding a non-round container having a substantially uniform side wall thickness from a rotationally symmetric parison, the apparatus comprising:
- a blow molding station including at least one blow mold, a heating station coupled to the molding station including a source of heat, and a transportation system extending through the heating station and the blow molding station for transporting parisons through the heating station and into the blow molding station, the transportation system including:
- a rotation driver for cyclically rotating the parisons at a prescribed non-uniform rate as the parisons are transported through the heating station to induce thermal variations in the parisons,
- at least one sensor for identifying an angular orientation of each parison at a selected position in the heating station, and
- repositioning apparatus for angularly reorienting each parison immediately prior to introduction into the blow molding station so that the thermal variations can be employed to facilitate formation of non-round containers having a substantially uniform side wall thickness within the blow molding station.
Apparatus for blow molding a non-round container having a substantially uniform side wall thickness from a rotationally symmetric parison, the apparatus comprising:
- a blow molding station including a number of blow molds having non-round interior surfaces, the number being an integer greater than zero, a heating station coupled to the molding station including a source of heat, and a transportation system extending through the heating station and the blow molding station for transporting parisons through the heating station and into the blow molding station in a step-wise fashion, the transportation system including:
- a series of parison holders, coupling elements coupling the parison holders together in an endless loop, and a stepping motor for transporting the series of parison holders in a step-wise fashion, each step advancing the entire series by a number of parison holders equal to the number of blow molds,
- a rotatable member carried by each parison holder having a parison engaging mandrel and a sprocket, a chain extending through the heating station and engaging the sprocket on each parison holder while the parison holder is in the heating station, and a servomotor engaging the chain to drive the chain at a prescribed cyclic non-uniform rate as the parisons are transported through the heating station to effect a predetermined non-uniform rotation and heating of each parison resulting in controlled thermal variations,
- at least one marker fixed to the rotatable member on each parison holder, and a number of detectors equal to the number of blow molds fixed at a selected position in the heating station to detect the at least one marker during a cycle of the non-uniform rate of rotation to define an angular orientation relation between the marker and a selected point in the cycle of the non-uniform rate of rotation, and
- a number of spindles equal to the number of blow molds positioned to engage the rotatable members on said number of the parison holders, a spindle servomotor coupled to each spindle, and a circuit for operating each spindle servomotor for a time sufficient to reconstruct the angular orientation relation between the marker and the selected point in the cycle of the non-uniform rate of rotation for each rotatable member and to reposition each parison to a desired orientation immediately prior to introduction into the blow molding station so that the thermal variations can be employed to facilitate formation of non-round containers having a substantially uniform side wall thickness within the blow molding station.
Dependencies are inferred from the claim text.