Double-Walled Preform Locking Assembly for Stable Blow Molding
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Solution Overview
Problem
Existing methods for producing double-walled preforms require expensive automation systems for assembling internal and external preforms before the blowing process, or involve costly welding downstream, compromising assembly stability during handling and transport.
Innovation Solution
The preforms are irreversibly assembled in a locked manner, allowing them to be handled as a single unit, with interference fit and gas flow channels ensuring stability and efficiency during processing and transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expensive automation systems are used to assemble internal and external preforms before blowing, then assembly stability is improved, but manufacturing cost increases
Solution Approach 1:
The locking means are integrally formed on the external preform during its manufacturing process, before assembly. This preliminary preparation eliminates the need for expensive automated assembly systems while ensuring stable locked interference fit with the internal preform during blowing operations
Solution Approach 2:
The locking means are designed to automatically engage with the internal preform through locked interference fit without requiring external automation systems. The structure itself provides the assembly function, reducing manufacturing costs while maintaining assembly stability
2Reliability
If welding is used to assemble preforms downstream, then assembly stability is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The locking means are formed on the external preform before assembly operations. This preliminary structuring enables simple mechanical interference fit assembly upstream, eliminating the need for complex downstream welding processes and reducing overall process complexity
Solution Approach 2:
The patent replaces the mechanical welding process with a mechanical interference fit system. The locking means create a locked interference fit that provides assembly stability without requiring thermal welding processes, simplifying the overall manufacturing process
3Ease of operation
If separate preforms are transported and assembled, then flexibility in handling is improved, but transport cost and time increase
Solution Approach 1:
The internal preform is inserted inside the external preform to form a nested assembled preform. This nested structure allows the two preforms to be handled as a single unit during transport, reducing transport time and costs while maintaining handling flexibility through the locked interference fit mechanism
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
This method reduces transport and automation costs, enhances handling stability, and allows direct feed into blow molding machines, expanding market applicability and ensuring safe gas flow.
Implementation Method 1
The interference fit is provided by the friction between the preforms which occurs when the inner preform is inserted into the outer preform
Data Source
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Figure 3~4
AI summary
An assembled preform (1) is provided for the making of a double-walled blown container, comprising a first external preform (10) which comprises a neck part (2) having an outer region (4) which includes a threaded region (5) and an inner region (3), and a second internal preform (11) arranged inside said first external preform (10), said internal preform (11) having a neck region (12) for cooperating in a locked manner with said inner neck region (3) of said external preform (10), and wherein between said external preform (10) and said internal preform (11) it is defined an inner volume (6) of interspace between the external preform (10) and the internal preform (11 ), said inner volume (6) being configured for the containing of a gas, and it is characterized in that said neck region (12) of said internal preform (11) comprises locking means (13,14,16) for cooperating by a locking interference with said inner region (3) of said neck part (2) of said external preform (10) when said internal preform (11) it is inserted in said external preform (10).