Universal Joining Strips for Concealed Mull Joints
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Solution Overview
Problem
Existing compound fenestration assembly mull joints face challenges in maintaining sufficient strength, especially with increased numbers of adjacent fenestration units, and often require disassembly or expose fasteners, compromising both structural integrity and aesthetic appeal under wind loads and other mechanical stresses.
Innovation Solution
The use of universal joining strips and components like gussets, locator plates, and end plugs forms mull joints that are mechanically interlocking, allowing for secure connection without disassembly and concealing fasteners, ensuring strength and appearance by transferring mechanical loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional fastening methods (screws through spacer boards or interlocking brackets) are used to join fenestration units, then the mull joint can provide sufficient strength to resist wind loads, but the fasteners become exposed on visible areas of the fenestration units, compromising aesthetic appeal
Solution Approach 1:
The fasteners are extracted from visible areas and relocated to non-visible areas. The system uses concealed fastening mechanisms where screws or other fasteners are installed from the interior side of the fenestration units, hidden behind the frame members, while the exterior sides maintain clean, fastener-free surfaces for aesthetic appeal.
Solution Approach 2:
A joining component acts as an intermediary between adjacent fenestration units, providing the mechanical connection while remaining hidden. The joining component includes features that engage with frame members from the interior side, transferring loads without requiring visible fasteners on the exterior surfaces.
2Strength
If multiple individual fenestration units are joined to form compound assemblies, then the overall structural strength can be increased, but the complexity of the mull joint assembly increases, requiring multiple different components
Solution Approach 1:
A universal joining component is designed to perform multiple functions across different fenestration unit configurations. The joining component can accommodate various frame member types and sizes through adjustable features, eliminating the need for different specialized components for different unit combinations.
Solution Approach 2:
Multiple functions are merged into a single joining component. The component integrates features for mechanical connection, load transfer, alignment, and concealment of fasteners all in one element, reducing the total number of separate parts needed in the mull joint assembly.
3Ease of manufacture
If fenestration units are joined using traditional methods, then the assembly process can be completed, but disassembly of fenestration units is required to access interior sides for installing fasteners, increasing installation time and complexity
Solution Approach 1:
The joining component is pre-configured with features that allow fasteners to be installed from the exterior side or through accessible openings, eliminating the need for disassembly. Alignment features are pre-built into the joining component to guide proper positioning before fastening, reducing installation time.
Solution Approach 2:
The traditional sequence is inverted: instead of requiring disassembly to access the interior side for fastener installation, the system allows fasteners to be installed from the exterior side or through concealed pathways that remain accessible during assembly, eliminating the disassembly step.
Data Source
AI summary
Compound fenestration assembly mull joints, compound fenestration assemblies using those mull joints, and methods of making and using the same are described herein. The mull joints in compound fenestration assemblies as described herein use universal joining strips to form both sides of a mull joint, as well as other universal components such as, e.g., corner gussets, locator plates, end plugs, seal members, etc. that may be used as needed to form mull joints as required in a compound fenestration assembly.