Mechanical Inversion of Thermoplastic Container Base
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Solution Overview
Problem
Existing thermoplastic container base designs fail to effectively manage internal vacuum created by the hot-fill process, leading to inefficiencies in volume control and potential over-pressurization or spilling when containers are opened.
Innovation Solution
A displacement device that mechanically inverts a truncated cone at the container base from an as-blown position to a displaced position, utilizing a plunger and collar mechanism to reduce internal volume and control pressure, allowing for precise vacuum or pressure management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a passive base design is used to allow internal vacuum force to create inward movement of the base panel, then the device complexity is reduced, but the control precision over vacuum management deteriorates
Solution Approach 1:
The patent introduces an intermediary mechanical system (plunger, collar, and base panel assembly) between the vacuum force and the container base. This intermediary mechanism allows controlled translation of the base panel in response to vacuum forces, providing precise vacuum management while maintaining relatively simple overall device complexity. The collar acts as a guide and constraint, ensuring controlled movement of the plunger and base panel.
2Manufacturing precision
If an active base design is used to apply external mechanical force to reposition the base inwardly, then the vacuum control precision is improved, but the device complexity increases
Solution Approach 1:
The patent employs a self-service mechanism where the vacuum force itself drives the base panel inward through the plunger and collar assembly. The system uses the available vacuum pressure to automatically reposition the base without requiring separate external actuation systems. This achieves precise vacuum control while minimizing device complexity by eliminating the need for additional motors, actuators, or control systems.
3Reliability
If the container base is allowed to cool creating internal vacuum, then the sterilization effectiveness is improved, but harmful factors generated by the container increase
Solution Approach 1:
The patent converts the harmful effect of internal vacuum into a beneficial mechanism for active base management. The vacuum force, instead of being merely a problem to be tolerated, is harnessed to drive the plunger and base panel inward, actively managing the container's internal volume and pressure. This transforms the vacuum from a harmful factor into a useful driving force for the displacement mechanism.
4Manufacturing precision
If the internal container volume is reduced to lower internal vacuum, then the vacuum management is improved, but the structural integrity may be compromised
Solution Approach 1:
The patent employs a dynamic base panel that can translate inward in response to vacuum forces, rather than a static rigid base. The plunger and collar assembly allows the base panel to move smoothly, dynamically adjusting the container's internal volume to manage vacuum pressures. This dynamic approach maintains structural integrity by distributing stresses through the moving mechanism rather than creating rigid constraints.
Data Source
AI summary
A displacement device for moving a truncated cone at a base of a container from an as-blown position to a displaced position. The base includes a deep base ring between a standing surface and the truncated cone. The displacement device includes a collar sized and shaped to be received within the deep base ring. A plunger includes a head at an end of a shaft extending through the collar. The head is sized and shaped to be received within the receptacle of the collar. The plunger is movable from a retracted position, at which the head is seated within the receptacle, to an extended position at which the head extends out from within the receptacle to allow the head to contact the truncated cone and move the truncated cone from the as-blown position to the displaced position.