Component-Isolating Grommet Assembly for Low-Force Fastener Insertion
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Solution Overview
Problem
Existing fastener assemblies, particularly those using H-style grommets, require high insertion forces that can damage components made of materials like carbon fiber, and involve a cumbersome process that is difficult to execute safely and securely.
Innovation Solution
A fastener assembly with a compression-limiting bushing and a grommet that includes a nose with a beveled tip and an intermediate channel, allowing for a clearance gap that enables the grommet to deform and securely couple to a component using lower insertion forces, along with a fastener that interacts with the bushing to limit relative motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a known H-style grommet is secured to a component by urging it through a hole and shoving a metal stamping or bushing into the grommet, then the grommet can be securely attached, but the process requires relatively high insertion forces that may cause damage to the grommet and/or component
Solution Approach 1:
The grommet is pre-loaded onto the bushing before final assembly, allowing the deformation to occur in a controlled manner during a single insertion stroke rather than requiring separate high-force operations. The clearance gap is pre-designed to accommodate the deformation sequence.
Solution Approach 2:
The clearance gap acts as an intermediary space that absorbs the deformation energy during insertion. This gap allows the grommet to progressively deform and conform to the component opening without transmitting excessive force to the component, thereby reducing insertion force requirements while ensuring reliable attachment.
2Reliability
If high insertion forces are used to insert the grommet into the component, then the grommet can be securely inserted, but components formed of certain materials such as carbon fiber may not be able to withstand the high insertion forces
Solution Approach 1:
The clearance gap serves as a buffer zone that decouples the insertion force from the component structure. As the grommet deforms into the clearance gap during insertion, the force is distributed over a longer distance and time, preventing concentration of stress that would damage carbon fiber or other fragile components.
Solution Approach 2:
The invention changes the deformation parameters by providing a controlled clearance gap that allows gradual compression and deformation of the grommet material. This transforms the insertion process from a high-force, sudden deformation event to a lower-force, progressive deformation process that protects the component.
3Reliability
If the grommet is deformed to securely couple to the component, then reliable coupling is achieved, but the process becomes more complex and difficult to execute
Solution Approach 1:
The invention merges the grommet attachment and bushing insertion operations into a single integrated action. The pre-loaded configuration and clearance gap design allow both components to be installed simultaneously in one stroke, eliminating the need for separate deformation and attachment steps, thereby simplifying the overall installation process while maintaining secure coupling.
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 allows for secure coupling of the grommet to a component with reduced insertion force, preventing damage and enabling the use with materials that cannot withstand high forces, while providing noise, vibration, and material isolation, and offering cost savings and improved clamping forces compared to previous designs.
Implementation Method 1
At least a portion of the grommet is configured to move into the clearance gap as the fastener assembly is urged into an opening of the component
Implementation Method 2
providing noise, vibration, and material isolation
Implementation Method 3
providing noise, vibration, and material isolation
Data Source
AI summary
A fastener assembly is configured to securely couple to a component. The fastener assembly includes a compression-limiting bushing, a fastener coupled to the bushing, and a grommet coupled to the bushing. A clearance gap is defined between one or both of the bushing or the fastener and the grommet. At least a portion of the grommet is configured to move into the clearance gap as the fastener assembly is urged into an opening of the component. The grommet is configured to securely couple to the component.