Facade Panel Screw Geometry for Self-Centering Fastening
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Solution Overview
Problem
Existing facade panel screws face challenges in securely fastening panels to thin metal substructures, particularly in handling external forces and thermal expansion, while also being prone to tilting and requiring complex installation processes, which can lead to visible fastening points and reduced load capacity.
Innovation Solution
A facade panel screw with a conical tip angle of 45° +/-5° and a double-threaded design, featuring a large head diameter and a thread-free underhead section, allowing for self-centering and high reverse torque without the need for pre-drilling, and incorporating a stop collar for secure fastening and aesthetic integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a high pitch is used to speed up assembly, then productivity is improved, but the screw tends to slant when formed in the pre-drilled hole
Solution Approach 1:
The patent applies preliminary action by providing a conical counterbore in the substructure before inserting the screw. This pre-prepared conical recess guides the screw during formation, preventing slanting even when high pitch is used for rapid assembly. The counterbore is formed in advance to match the screw's conical shape, ensuring proper alignment throughout the fastening process.
2Reliability
If a large head diameter is used to ensure holding function, then reliability is improved, but the edge of the screw head may hit the surface of the facade panel
Solution Approach 1:
The patent resolves this contradiction by introducing a vertical dimension through the conical counterbore. Instead of increasing head diameter horizontally (which would contact the panel surface), the solution provides vertical clearance by forming a conical recess in the substructure. This allows a large-diameter head to be used for reliable holding while the counterbore prevents the head edge from contacting and damaging the facade panel surface.
3Manufacturing precision
If pre-drilling is performed in the substructure, then manufacturing precision is improved, but the process complexity increases
Solution Approach 1:
The patent merges two separate operations (drilling and counterboring) into a single machining step. The conical counterbore is formed simultaneously with or integrated into the pre-drilling process, eliminating the need for separate operations. This reduces process complexity while maintaining the precision benefits of pre-drilling, as the conical shape is created in one continuous action rather than multiple discrete steps.
4Ease of operation
If a conical counterbore is formed in the substructure, then ease of operation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by specifying precise geometric parameters for the conical counterbore, including the half-angle α (5° to 15°) and depth-to-diameter ratio (0.5 to 2.0). By defining these specific parameter ranges, the patent balances ease of operation (self-centering effect) with manufacturability. The controlled parameters ensure the counterbore provides sufficient guidance without requiring excessively tight tolerances that would make manufacturing difficult.
Data Source
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AI summary
A facade panel screw for the optimized fastening of facade panel elements to a substructure has a head with a very large diameter DK, a substantially cylindrical shank that is at least partially threaded (nominal diameter DS), and a conical tip with a point angle γ. The thread extends continuously from the shank to the tip. Characteristic features include a point angle γ of 45° ± 10°, a thread that is at least double-start, a head diameter DK that is at least twice the nominal diameter DS, and the absence of a drill point. Such a facade panel screw is used in a fastening assembly comprising a load-bearing component (substructure) and a facade panel.Due to its design, the facade panel screw is able to simplify the fastening of the facade panel and at least partially correct any skewed approach during installation.