Plastic Fastening Insert Structure for Corrosion-Free Composite Anchoring
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Solution Overview
Problem
Existing fastening systems for fiber-reinforced materials face issues with holding forces, electrochemical corrosion, and inaccurate positioning, particularly when using metallic fasteners with carbon fiber reinforced plastics, leading to weakened connections and increased costs.
Innovation Solution
A T-shaped fastening insert made of plastic with an insert disc and shaft, featuring a disrupted structure with passage openings and toothing for secure positioning and a metallic functional structure enclosed within the shaft to prevent electrochemical corrosion, ensuring reliable anchoring and load-bearing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic fastening elements are used, then connection strength is improved, but electrochemical corrosion occurs leading to weakened connections
Solution Approach 1:
The patent introduces a plastic fastening insert as an intermediary element between the carbon fiber reinforced plastic component and any metallic fastening elements. This insert prevents direct contact between metal and carbon fiber, eliminating the electrochemical corrosion pathway while still providing the necessary mechanical strength for connections.
Solution Approach 2:
The invention changes the material parameter of the fastening insert from metallic to plastic (specifically polyamide with high melting point), fundamentally altering the electrochemical properties to prevent corrosion while maintaining mechanical functionality through the plastic material's inherent strength and bonding characteristics.
2Productivity
If passage openings are added to fastening insert, then material flow and anchoring are improved, but positioning accuracy deteriorates
Solution Approach 1:
The patent employs asymmetric positioning features including an asymmetric recess in the fastening insert that receives a corresponding asymmetric protrusion from the injection mold. This asymmetric geometry provides unique, accurate positioning while the passage openings maintain their function for material flow, as the positioning features are strategically located away from the opening areas.
Solution Approach 2:
The fastening insert design segments the functions: the main body contains positioning features for accurate placement, while separate passage openings are strategically positioned to allow material flow. The positioning protrusions and recesses are distinct from the passage opening locations, allowing both functions to coexist without interfering with each other.
3Stability of the object's composition
If continuous plate structure is used, then fastening insert stability is improved, but material-fit connection between material layers is prevented
Solution Approach 1:
The patent incorporates passage openings through the fastening insert plate, creating a porous structure that allows curable material to flow through and bond adjacent material layers. The plate maintains its stability through the strategic placement and sizing of these openings, which are designed to provide sufficient structural integrity while enabling material penetration for layer-to-layer bonding.
Solution Approach 2:
The invention merges the functions of structural support and material layer bonding by incorporating passage openings that allow curable material to pass through the fastening insert. This enables the fastening insert to simultaneously provide mechanical stability and facilitate the creation of material-fit connections between adjacent layers through the hardened material in the passages.
Data Source
AI summary
A fastening insert made of plastic with a T-shaped configuration consisting of an insert disc and a hollow cylindrical shaft fastened to the insert disc. The insert disc has a plurality of passage openings arranged off-center, at least one of which has an edge projection extending circumferentially continuously or circumferentially in sections, which is formed as toothing and extends on one side or both sides beyond the respective fastening side of the insert disc. This toothing ensures an additional form-fit connection or fixation of the fastening insert in a preferably fiber-reinforced composite material.