Two-Piece Clip Engagement Geometry for Easy Reuse Return
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Solution Overview
Problem
Conventional two-piece clips face difficulties in efficiently returning to a reusable position, requiring high operational force and complex procedures.
Innovation Solution
A two-piece clip design featuring a grommet with engagement convex portions and a pin with engagement concave portions, allowing for elastic deformation and easy extraction by adjusting the inclination angles and contact areas, reducing operational force and improving workability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the body portion of the grommet is elastically deformed outward to clamp members in the standard position, then the fastening strength is improved, but the operational force required to return to reusable position increases
Solution Approach 1:
The engagement concave portion is divided into two distinct engagement regions: a first engagement region with a first inclined surface and a second engagement region with a second inclined surface. This segmentation allows different portions of the pin to engage with different regions of the grommet at different stages, enabling controlled elastic deformation and reduction of operational force during the return to reusable position.
Solution Approach 2:
The invention changes the geometric parameters of the engagement surfaces by providing inclined surfaces with different slopes. The first inclined surface has a specific angle designed for initial engagement and clamping, while the second inclined surface has a different angle optimized for the return stroke. This parameter variation allows the system to achieve both strong fastening and easy release.
2Ease of operation
If the pin is pushed into the grommet to the maximum push-in position, then the body portion can be easily extracted, but the fastening reliability is reduced
Solution Approach 1:
The grommet body portion is pre-designed with elastic properties and split configurations that allow it to be temporarily deformed during insertion and removal operations. The slits in the grommet body enable controlled elastic deformation that facilitates easy extraction when needed, while the overall structure maintains sufficient rigidity to ensure fastening reliability during normal operation.
Solution Approach 2:
The invention introduces dynamic characteristics to the fastening system through the elastic deformability of the grommet body portion. The body can dynamically adjust its shape during insertion and extraction operations, transitioning between rigid (for fastening) and flexible (for extraction) states. This dynamic behavior enables easy extraction at maximum push-in position while maintaining fastening reliability during clamping.
3Reliability
If the engagement concave portion is made deeper, then the pin engagement is improved, but the structural complexity of the grommet increases
Solution Approach 1:
The engagement concave portion is segmented into two functional regions with different depths and inclined surfaces. The first engagement region provides initial engagement with a shallower depth, while the second engagement region provides additional engagement with greater depth. This segmentation achieves improved overall engagement reliability without requiring a uniformly deep concave portion, thereby controlling structural complexity.
4Adaptability or versatility
If the body portion is split by multiple slits, then the elastic deformation capability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The slits are strategically positioned and sized to create local flexibility zones where elastic deformation is needed, while maintaining structural integrity in other areas. The slits are configured to provide sufficient elastic deformation capability for insertion and extraction operations without requiring extremely precise positioning, as the local flexibility compensates for minor manufacturing variations.
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 design enhances workability by simplifying the return to a reusable position and increasing removal resistance, making the clip easier to use and more effective in fastening and releasing members.
Implementation Method 1
the body portion of the grommet is elastically deformed outward, and the two members provided with the attachment holes are mutually fastened together
Implementation Method 2
the body portion of the grommet bended outward in the standard position elastically returns so as to be capable of resolving the fastening of the body portion of the grommet to the attachment holes
Data Source
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AI summary
An engagement convex portion is formed in a grommet of a two-piece clip, and a head portion-side engagement concave portion is formed in a pin of the two-piece clip. When the pin is pushed into the grommet to a maximum push-in position, an inner end of the engagement convex portion of the grommet abuts against a middle of a tip-side concave portion wall surface of the head portion-side engagement concave portion. Thus, in the maximum push-in position, when a tip portion of the pin is pushed back in an extracting direction, the tip-side concave portion wall surface of the head portion-side engagement concave portion of the pin slides against the inner end of the engagement convex portion of the grommet.