Curtain-wall mullion screw race with thin web
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Solution Overview
Problem
The assembly of curtain walls is time-intensive and labor-intensive due to the difficulty in penetrating mullion tongue screw-races, which can lead to errors and reduced pull-out strength of threaded fasteners, especially when the screw 'walks' during installation and the web portion is thick or varies in design.
Innovation Solution
A curtain-wall mullion with an H-shaped screw race configuration, featuring inwardly and outwardly extending screw-race lips and a thin intermediate web section, allows for rapid penetration and secure engagement of threaded fasteners, enhancing pull-out strength and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick web portion screw race design is used, then structural strength is improved, but penetration time and labor intensity increase
Solution Approach 1:
The screw race is divided into multiple segments or zones with varying web portion thicknesses. The race includes a first portion with greater web thickness for strength and a second portion with reduced web thickness for faster penetration, allowing the fastener to engage critical areas without unnecessarily penetrating through the entire thickness.
Solution Approach 2:
Different regions of the screw race are given different local properties - specifically, the web portion thickness is varied locally along the length of the race. This allows optimal penetration speed in certain zones while maintaining structural strength in others, resolving the contradiction between speed and strength.
2Ease of operation
If manual alignment and drilling is used, then flexibility is maintained, but accuracy and speed decrease
Solution Approach 1:
The screw race is designed with self-aligning features that guide the threaded fastener into the correct position automatically during insertion. The geometry of the race lips and web portion creates natural alignment cues that eliminate the need for precise manual positioning while maintaining operational simplicity.
3Strength
If varied web portion thickness is used, then structural optimization is achieved, but manufacturing complexity increases
Solution Approach 1:
The web portion thickness parameter is varied along the length of the screw race to optimize structural performance. By changing this single geometric parameter in a controlled manner, the design achieves improved strength-to-weight ratio and optimized fastener engagement without introducing complex multi-dimensional variations.
Data Source
AI summary
A curtain wall system having a mullion mounting tongue screw-race configuration for improving the efficiency and reliability of curtain wall elements assembled thereto. The curtain wall system includes a face, a first leg, and a second leg. The first and second leg are integrally formed with and extend outwardly from the face and are interconnected via an intermediate web section. Each of the first leg and the second leg include an outer screw-race lip and an inner screw-race lip. The inner screw-race lips and the outer screw-race lips are disposed on opposite sides of the intermediate web section to form a screw race. The inner screw-race lips and the outer screw-race lips are spaced apart by a distance affording engagement by a threaded fastener against each of the inner screw-race lips and the outer screw-race lips. A thickness of the intermediate web section is less than a thickness of the first leg and of the second leg.