Flanged Duct Assembly Using Self-Aligning Screws and Corner Plates
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Solution Overview
Problem
Current methods for assembling and hanging duct sections using inserted corner plates are inefficient, labor-intensive, and prone to misalignment, leakage, and safety hazards, particularly in high-elevation installations, due to the use of drift pins, adhesive gaskets, and conventional fastening systems which are imprecise and costly.
Innovation Solution
The use of large sheet metal screws with specially configured holes in inserted corner plates allows for precise alignment and assembly of duct sections without initial threaded engagement, enabling self-holding and guiding of duct sections for final alignment and sealing, while also facilitating the incorporation of hangers directly into the assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If drift pins are used for aligning duct sections, then alignment is facilitated, but the tapered shape and gasket presence prevent final close alignment and hold sections apart improperly
Solution Approach 1:
The invention removes the drift pin from the system entirely and replaces it with a gasket that has built-in alignment features. The gasket's protruding portion with alignment holes directly provides the alignment function, eliminating the need for a separate drift pin component.
Solution Approach 2:
The invention combines the alignment function and sealing function into a single integrated gasket component. The gasket simultaneously seals the joint between duct sections and provides alignment features through its protruding portion with holes, merging two previously separate functions.
2Reliability
If adhesive gasket is applied to duct sections, then sealing is achieved, but misalignment causes difficult detachment and ruin of the gasket requiring costly replacement
Solution Approach 1:
The invention performs alignment before applying the adhesive gasket. The gasket's protruding portion with alignment holes allows precise positioning and alignment of duct sections to be established first, ensuring proper alignment before the adhesive is applied and the sections are permanently bonded.
3Reliability
If tape gasket is applied to vertical duct section, then sealing is achieved, but gravity and sharp bending around corner plate area compromise adhesion and cause tape to fall off
Solution Approach 1:
The invention performs alignment using the gasket's protruding portion with alignment holes before the adhesive side is exposed or applied. This preliminary alignment step ensures proper positioning is established while the gasket is still in its protective state, avoiding the problems of applying tape to vertical surfaces with sharp bends around corner plates.
4Strength
If multiple fasteners are used through corner plates, then connection strength is improved, but threading force and assembly time increase
Solution Approach 1:
The invention removes the corner plate from the system entirely and integrates its fastening function directly into the gasket. The gasket's protruding portion with holes serves both as an alignment feature and as the mounting surface for fasteners, eliminating the need for separate corner plates and reducing assembly steps.
Solution Approach 2:
The gasket serves multiple functions simultaneously: it seals the joint between duct sections, provides alignment features through its protruding portion, and serves as the mounting surface for fasteners. This multi-functionality consolidates what were previously separate components (gasket, corner plate, alignment feature) into a single universal component.
5Ease of operation
If clips are used to clamp flanges, then assembly is facilitated, but clips slide down and fall from ducts creating safety hazards
Solution Approach 1:
The invention removes clips from the system entirely and replaces them with screws that fasten directly through the gasket's protruding portion. This eliminates the safety hazard of clips sliding down and falling while maintaining the ability to facilitate assembly through the gasket's built-in alignment holes.
Data Source
AI summary
A system and method of assembling flanged duct sections, using large sheet metal screws through opposing inserted corner plates. The large screws are threadedly inserted fully through the corner plates of a first duct section and hold perpendicular thereto for guiding alignment with the mating duct section. The screws hold the duct sections apart to allow aligning them without fluid sealant or tape gasket material on one of the duct sections contacting the other. The screws are then threadedly engaged with the corner plates of the mating duct section, bringing the duct sections together with a leak resistant seal therebetween. Optional hanger brackets can be placed between the corner plates before assembly, and additional screws used to deform the flanges and corner plates about the brackets to compress the sealant or gasket thereabout.