Stretch-Blow Molded Container Deep Grip Design
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Solution Overview
Problem
Existing methods for producing stretched-blow molded containers with integrally molded deep grips are limited in size and ergonomics, particularly for large containers, as they either restrict volume or do not allow for sufficient depth of the molded hand grip for ergonomic handling.
Innovation Solution
A process involving a two-stage stretch-blow molding technique where convex deformable regions are formed in the side walls of an intermediate container, which are then inverted to create a deep concave grip with an undercut region, allowing for a larger volume and improved ergonomics, and can be performed either below or above the glass transition temperature of the polymer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If deformable convex regions are formed in flat and opposite parallel vertical walls of the intermediate container, then the container structure is simple, but the container size and volume are limited for ergonomic gripping
Solution Approach 1:
The patent transitions from forming deformable regions in flat vertical walls to forming them in curved portions of the container side wall. This dimensional change from planar to curved surfaces allows the container to achieve larger volume while maintaining ergonomic gripping capabilities, as the curved geometry provides better hand contact areas without restricting container size
2Volume of moving object
If the deformable convex regions are formed in curved portions of the container side wall to enable large volume, then the container volume increases, but the depth of the concave regions forming the molded hand grip is limited
Solution Approach 1:
The patent incorporates recesses in the blow mold cavity that correspond to the desired grip locations before the blow molding process begins. These pre-formed recesses guide the deformation of convex regions during boxing to ensure sufficient grip depth is achieved, even when working with curved wall geometries and large container volumes
3Manufacturing precision
If hot boxing is used to invert the outward bubbles forming deformable convex regions, then the grip depth can be sufficient for ergonomic gripping, but the process cannot be carried out below the glass transition temperature
Solution Approach 1:
The patent creates localized recesses in the blow mold cavity at specific grip locations, which concentrate the deformation process in these predetermined areas. This local quality approach allows cold boxing to achieve sufficient grip depth by focusing the inversion action on specific regions with pre-formed recesses, rather than requiring uniform heating across the entire container
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the production of stretched-blow molded containers with deep, ergonomic grips suitable for large volumes, enhancing user handling while maintaining flexibility in processing conditions.
Implementation Method 1
a preform is heated and then stretch-blow molded in a blow mold cavity
Implementation Method 2
each deformable region of the intermediate container is mechanically pushed inwardly to invert the deformable region and form a molded hand grip
Implementation Method 3
when the temperature of the first intermediate stretched-blow molded container is below ('cold boxing') the glass transition temperature (Tg) of the polymer constituting the container, or when the temperature of the first intermediate stretched-blow molded container is above ('hot boxing') said glass transition temperature (Tg)
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The intermediate stretched-blow molded container (1 ) comprises a biaxially stretched-blow molded hollow body (10) that comprises a container side wall (10a), at least one recess (101 ) that is formed in said container side wall (10a), that is off-center from the second vertical central plane (P2), and at least one convex and outwardly protruding deformable region (102) that is formed in the container side wall (10a).The maximum gripping dimension (DR) of the stretched-blow molded hollow body (10) measured next to and on one side of the convex and outwardly protruding deformable region (102) is smaller than the maximum dimension (DL) of the stretched-blow molded hollow body (10) measured next to and on the other side of convex and outwardly protruding deformable region (102). Said convex and outwardly protruding deformable region (102) comprises an outwardly protruding invertable lateral wall (1020) that is an extension of a second lateral wall (1011 ) of the recess (101 ) and that extends beyond a first lateral wall (1010) of the recess (101 ), and a front wall (1021 ) that is an extension of this outwardly protruding invertable lateral wall (1020). The junction (H) between the bottom portion (1012) and the second lateral wall (101 1 ) of said recess (101 ) forms an hinge on the whole periphery of the outwardly protruding convex deformable region (102) for inverting the said outwardly protruding convex deformable region ((102) and the second lateral wall (101 1 ) of the recess (101) by pushing them inwardly in order to form a concave grip (G).