Wide Back Flange Hanger for Narrow Web Members
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Solution Overview
Problem
Existing sheet metal hangers for connecting joists or truss members to trusses often require overlapping back flanges for adequate fastener spacing, which complicates attachment to narrow vertical web members and limits optimal fastener placement.
Innovation Solution
A hanger design featuring reflex-bent side members with inwardly bent back flanges that span a wider width than the side members, allowing for non-overlapping fastener placement and improved attachment to narrow vertical web members without welding or painting, using a single blank of galvanized sheet metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If back flanges are made wide to allow optimal fastener spacing, then fastener spacing is improved, but the hanger requires overlapping flanges which complicates attachment to narrow vertical web members
Solution Approach 1:
The back flanges are configured to extend beyond the side members in the horizontal dimension, creating a wider attachment surface than the side member spacing would normally permit. This dimensional extension allows multiple fasteners to be properly spaced on narrow web members without requiring the flanges to overlap vertically.
2Adaptability or versatility
If side members are spaced close together to support narrow supported members, then support for narrow members is improved, but fastener spacing on back flanges is reduced
Solution Approach 1:
The back flanges extend horizontally beyond the lateral boundaries of the side members, effectively decoupling the fastener spacing dimension from the side member spacing dimension. This allows the side members to be close together for supporting narrow members while the back flanges provide sufficient width for optimal fastener placement.
3Ease of manufacture
If hanger is made from single blank of sheet metal without welding or painting, then fabrication complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The entire hanger assembly including seat member, side members, and back flanges is formed as a single integrated piece from one blank of galvanized sheet metal. This eliminates the need for separate welding operations and painting steps, reducing fabrication complexity while the reflex angle geometry provides inherent structural integrity.
Solution Approach 2:
The sheet metal is formed into reflex angles (angles greater than 180 degrees) at critical junctions, creating rigid geometric features that maintain structural integrity through the forming process. This geometric parameter change allows the single-blank construction to achieve the required strength without welding.
Data Source
AI summary
A hanger for supporting a held member from a holding member is provided with a seat member adapted for supporting the held member, first and second side members connected to the seat member, the first and second side members having lower portions and upper portions, the lower portions of the first and second side members each having inner an face and an outer face with the inner faces facing each other, and the upper portions of the first and second side members being connected to first and second back flanges respectively, the upper portions of the first and second side members each having an inner face and an outer face, and the first and second back flanges being adapted to be connected to the holding member by a plurality of fasteners, wherein the inner faces of the lower portions of the first and second side members and the inner faces of the upper portions of the first and second side members form reflex angles with each other.