Integral Seal Fastener Assembly for Secure Panel Sealing
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Solution Overview
Problem
Existing fastening techniques for automotive panels face challenges in maintaining the integrity of integral seals during shipping, handling, and installation, as they can become separated from the fastener stem, and require labor-intensive connection processes.
Innovation Solution
A fastener assembly with a rigid part component and an integral flexible seal, fabricated using a two-shot injection process, where the flexible seal is molded first with a non-circular cross-section interface, such as dovetail, to enhance retention and sealing capabilities, and the rigid part component is molded subsequently, ensuring a strong and reliable bond.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal is fabricated from a different seal material than the fastener material, then the sealing effectiveness is improved, but the seal can become separated from the fastener stem during shipping and handling
Solution Approach 1:
The patent combines the seal and fastener into a single integral component through two-shot molding, where the seal material is molded directly onto the fastener stem. This merging eliminates the separation issue while maintaining different materials for sealing and structural functions.
Solution Approach 2:
The patent uses composite construction with two different materials: a rigid fastener material (e.g., polypropylene) and a flexible seal material (e.g., thermoplastic elastomer). The two-shot molding process creates a composite part where each material performs its optimal function while being permanently bonded.
2Reliability
If a seal is connected with the fastener using a secondary post-molding operation, then the seal can be attached to the fastener, but the process becomes labor intensive and time consuming
Solution Approach 1:
The patent performs the seal attachment action during the initial molding process itself (two-shot molding), rather than as a subsequent secondary operation. The seal material is molded directly onto the fastener stem in the same manufacturing cycle, eliminating post-molding labor.
Solution Approach 2:
The patent merges the seal attachment operation with the fastener manufacturing operation into a single two-shot molding process. This consolidation eliminates the need for separate post-molding assembly steps, significantly improving productivity.
3Stability of the object's composition
If a non-circular cross-section interface, such as dovetail, is used between the fastener and seal, then the retention characteristics are improved, but the manufacturing complexity increases
Solution Approach 1:
The patent employs an asymmetric non-circular cross-section (dovetail interface) at the bond line between the seal and fastener. This asymmetric geometry provides mechanical interlocking that significantly improves retention characteristics while the two-shot molding process captures the geometry in a single operation.
Solution Approach 2:
The patent changes the geometric parameters of the bond interface from a simple circular cross-section to a complex non-circular dovetail profile. This parameter change enhances mechanical retention through interlocking geometry, and the two-shot molding process is capable of producing this complex geometry without additional manufacturing steps.
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
The solution provides improved retention characteristics and sealing performance between the fastener and seal portions, reducing the risk of separation and simplifying the installation process while maintaining a compact design.
Implementation Method 1
fabricated using a two-shot injection process, where the flexible seal is molded first with a non-circular cross-section interface
Data Source
AI summary
Disclosed are systems and methods for coupling a first panel to a second panel via a fastening system, such as a pin and grommet (P&G) fastener having a grommet and a fastener assembly. The fastener assembly includes a rigid part component and a flexible seal that is integrally coupled with the rigid part component at an interface. The flexible seal is fabricated from a first material and the rigid part component is fabricated from a second material that is different from the first material. The interface defines one or more dovetails or other features to interlock the flexible seal with the rigid part component.