Swivel D-Ring Attachment Point for Fall Protection
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Solution Overview
Problem
Existing D-ring attachment points for fall protection in construction lack the necessary mobility and adaptability to prevent twisting or knotting of lanyards, and do not effectively distribute loads when used with webbing, especially under high forces like those required by ANSI standard Z359.1.
Innovation Solution
A swivel D-ring attachment point with a first circular aperture for carabiner attachment and a second rectangular aperture for webbing, allowing 360-degree swiveling and featuring a shear pin mechanism for overload indication, ensuring balanced loading and reduced risk of twisting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional D-ring with two identical closed apertures is used, then the structure is simple and strong, but the lanyard twists and knots due to lack of mobility
Solution Approach 1:
The patent applies the dynamics principle by making the D-ring swivelable, allowing it to rotate freely around its axis. This dynamic capability enables the lanyard to move with the worker's motion, preventing twisting and knotting while maintaining structural strength. The swivel mechanism transforms the static D-ring into a dynamic component that adapts to changing load directions.
Solution Approach 2:
The patent segments the D-ring into two distinct attachment portions with different aperture configurations. The first attachment portion has a first closed aperture for one type of connection, while the second attachment portion has a second closed aperture for another type of connection. This segmentation allows each portion to be optimized for its specific function while maintaining overall structural integrity.
2Adaptability or versatility
If a single aperture shape is used in the D-ring, then the structure is simple, but it cannot effectively connect to substantially different articles like carabiners and webbing
Solution Approach 1:
The patent implements universality by designing the D-ring with multiple attachment portions that can connect to different types of articles. The first attachment portion with its first closed aperture is optimized for carabiner connections, while the second attachment portion with its second closed aperture is optimized for webbing connections. This multi-functional design allows a single D-ring to serve multiple connection purposes.
Solution Approach 2:
The patent applies local quality by giving each attachment portion distinct aperture characteristics suited to its specific connection type. The first aperture is configured with properties optimal for carabiner engagement, while the second aperture has properties optimal for webbing passage. Each local region of the D-ring is optimized for its specific function rather than using a uniform design.
3Strength
If the D-ring structure is simplified, then manufacturing is easier, but load distribution across webbing is ineffective under high forces
Solution Approach 1:
The swivel capability allows the D-ring to dynamically adjust its orientation to distribute loads evenly across the webbing and attachment points. Under high forces, the swivel mechanism ensures that the load is distributed along the grain of the webbing rather than concentrating at single points, maintaining structural strength while using a relatively simple overall structure.
Data Source
AI summary
A first attachment portion has a first closed aperture defining a circular ring portion that extends over a first circumferential range of at least 180 degrees of arc that is symmetrically disposed relative to an axis. A second attachment portion has a second closed aperture. The first and second attachment portions are joined together so as to permit freely swiveling one of the attachment portions relative to the other around the axis. The second aperture has a shape that is substantially different from the shape of the first aperture, for connecting to substantially different articles.