Roof Truss Strap Buckle Pinch Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for securing roof trusses to load-bearing walls do not adequately provide both horizontal and uplift resistance, particularly in high wind conditions, which can lead to wind uplift and damage to roofing systems.
Innovation Solution
A system comprising an angled strap with a flat central portion and two arms at a 22-degree bend, combined with a buckle and top plate, is used to secure the roof truss to the load-bearing wall, providing both horizontal and uplift resistance by pinching the strap between the buckle and the wall, and attaching it with screws or nails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metal straps are used to secure roof trusses to load-bearing walls, then the attachment is simple and straightforward, but the system does not adequately provide both horizontal and uplift resistance simultaneously
Solution Approach 1:
The attachment system is divided into separate functional components: a strap for securing the truss, a buckle for creating mechanical interlocking, and a top plate for distributing loads. Each component performs a specific function, allowing the system to provide both horizontal and uplift resistance through coordinated action of segmented parts rather than a single monolithic element.
Solution Approach 2:
The strap is threaded through the buckle in a nested configuration where the strap passes through the buckle's opening and is secured by the top plate. This nested arrangement allows the components to work together in a compact assembly that achieves complex structural performance through layered integration of simpler elements.
2Reliability
If the strap is extended to the top of the load-bearing wall and pinched between the wall and the buckle, then uplift resistance is improved, but the installation complexity increases
Solution Approach 1:
The buckle is positioned at the top of the load-bearing wall before the strap is fully installed. The strap is then threaded through the pre-positioned buckle, allowing the pinching action to occur naturally during the installation process rather than requiring complex post-installation adjustments. This preliminary positioning of the buckle simplifies the overall installation sequence.
Solution Approach 2:
The buckle acts as an intermediary device between the strap and the top plate. It provides a mechanical interface that converts the simple act of placing the top plate over the strap into an effective pinching action that secures the strap against the wall, thereby achieving uplift resistance without requiring complex direct attachment methods.
3Reliability
If the top plate is placed on the buckle to pinch the strap, then both horizontal and uplift forces are resisted, but the number of components and assembly steps increases
Solution Approach 1:
The top plate serves multiple functions simultaneously: it secures the strap against the buckle to create the pinching action, distributes uplift forces across a wider area of the wall, and provides a bearing surface for horizontal loads. This multi-functionality allows a single additional component to address multiple performance requirements without proportionally increasing system complexity.
Solution Approach 2:
The buckle and top plate are combined into an integrated assembly where the top plate rests on the buckle's flanges. This merging of components creates a unified load-path structure that simultaneously resists both horizontal and uplift forces through the coordinated geometry of the combined elements, rather than requiring separate systems for each force type.
Data Source
AI summary
A system and method for securing a roof truss to a load bearing wall is disclosed. A strap is attached to a roof truss at one end and extended to the top of a load-bearing wall. A buckle is placed over the strap to pinch the strap between the vertical and horizontal arms of the buckle. The end of the strap is wrapped back toward the vertical side of the roof truss and a flat plate is placed to pinch the free end of the strap between the buckle and the flat plate. Screws are placed through holes in the flat plate and corresponding holes in the buckle to attach the system to the top of the load-bearing wall. The system and method of the invention provides both horizontal (lateral) resistance and uplift resistance, thus resisting horizontal (lateral) forces while at the same time providing uplift resistance.