Two-Material Panel Fastener With Overmolded Scratch Protection
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Solution Overview
Problem
Existing fasteners made of two different materials for attaching panels to frames in the automotive industry are cumbersome to manufacture and use, and they often cause paint scratches or abrasion during assembly and disassembly, with limited adjustability in mounting and dismounting forces.
Innovation Solution
A fastener design featuring a body element and a support element made of different plastic materials, where the softer second material is overmolded to adjust mounting and dismounting forces and protect against paint scratches, with a conical stem and flange configuration that includes a spring collar and flexible flaps for easy assembly and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a two-material fastener design is used to protect against paint scratches and adjust mounting forces, then the protection against paint damage and adjustability is improved, but the manufacturing complexity increases
Solution Approach 1:
The support element is overmolded onto the body element, creating a nested structure where the softer second material is integrated onto the harder first material. This nesting approach allows the two-material design to protect against paint scratches while maintaining a compact, integrated fastener structure that simplifies manufacturing compared to separate components.
Solution Approach 2:
The fastener combines two different plastic materials with distinct properties: a harder first material for structural integrity and a softer second material for paint protection and force adjustment. This composite material approach resolves the contradiction by providing both protection functionality and structural performance within a unified fastener design.
2Adaptability or versatility
If the support element is overmolded on the engaging member to adjust mounting forces, then the adjustability of mounting and dismounting forces is improved, but the device complexity increases
Solution Approach 1:
The overmolded support element allows adjustment of mounting and dismounting forces by varying the thickness and position of the second plastic material. This parameter change approach enables force adaptability without adding complex mechanical adjustment mechanisms, as the force characteristics are controlled by geometric parameters of the overmolded portion.
3Object-affected harmful factors
If the second plastic material is positioned to cover all contact parts, then the protection against paint abrasion is improved, but the manufacturing complexity increases
Solution Approach 1:
The second plastic material is strategically positioned only at specific locations where paint contact occurs, such as the perimeter of the flange and portions of the engaging members. This local quality approach provides paint protection precisely where needed without requiring complete coverage, thereby reducing manufacturing complexity compared to full-coverage designs.
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 simplifies manufacturing and assembly, reduces the risk of paint damage, and allows for adjustable mounting and dismounting forces by utilizing the softer material to cushion contact points, enhancing the ease of use and durability of the fastening process.
Implementation Method 1
the second plastic material is softer (or less rigid) than the first plastic material... allows to adjust the mounting and dismounting forces by adjusting the thickness of the material... protecting all the parts of the body element which are possibly in contact with the panel or the frame to be covered by a softer material and thus lowering the risks of paint scratching or abrasion
Data Source
Figure 1~2
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Figure 5~6
AI summary
Fastener (10) for attaching a panel to a frame comprising a body element (12) made in a first plastic material and a support element (14) made in a second plastic material, the second plastic material being less rigid than the first plastic material, the support element being at least in part overmolded on the body element. The body element comprises: - a flange (16) having an internal and an external surface opposite the internal surface, the flange (16) being flat and having a rim (18), - a stem (20) extending from the internal surface until a free end portion (22), wherein the free end portion of the stem has a conical shape, - a grip portion (27) arranged on the external surface of the flange, - engaging members (24, 26) extending from the stem and expanding obliquely upwards toward the internal surface of the flange, and the support element (14) is overmolded on the rim and extends externally forming a spring collar extending at the perimeter of the flange and forming a non-zero angle with the flange, and wherein the support element is further overmolded on the engaging members.