Touch Fastener Energy-Dissipating Link for Smoother Fall Arrest
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Solution Overview
Problem
Current energy dissipating devices used in fall prevention systems, such as those for rock and wall climbing, often subject climbers to injurious arresting forces due to abrupt halting of free falls, as they primarily rely on discrete connection points that break or tear under tensile force, leading to uneven energy dissipation and potential micro shocks during fall arrest.
Innovation Solution
The development of energy dissipating links featuring multiple independent closures formed by releasably engageable touch fasteners, which utilize tensile overload to progressively disengage and re-engage fasteners in shear and peel configurations, effectively distributing and dissipating kinetic energy to reduce the maximum arrest force experienced by the climber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If discrete connection points are used to dissipate energy, then energy dissipation is achieved, but injurious arresting forces and micro shocks occur due to abrupt halting
Solution Approach 1:
The energy dissipating link is segmented into multiple independent closures (first closure with first set of fasteners, second closure with second set of fasteners) that can disengage progressively rather than simultaneously. This segmentation allows the kinetic energy to be dissipated in controlled stages, reducing the abruptness of the arresting force and eliminating micro shocks that occur when discrete connection points fail all at once.
Solution Approach 2:
The fasteners are designed with dynamic disengagement characteristics where the first closure disengages in shear and the second closure disengages in peel under tensile overload. This dynamic behavior allows the system to adapt its energy dissipation mechanism based on the applied load, providing a smoother deceleration profile that reduces harmful arresting forces while maintaining effective kinetic energy dissipation.
2Object-affected harmful factors
If multiple independent closures are used with progressive disengagement, then arresting force is reduced and micro shocks are eliminated, but device complexity increases
Solution Approach 1:
Multiple independent closures are merged into a single integrated energy dissipating link structure, where the first and second closures share common structural elements and are permanently coupled to the same elongated base. This merging approach achieves the benefit of progressive disengagement and reduced arresting forces while avoiding the complexity of completely separate devices, as the multiple closures work together as a unified system.
Solution Approach 2:
The touch fasteners serve multiple functions: they form both the first and second independent closures, provide progressive disengagement under different loading conditions (shear for first closure, peel for second closure), and collectively dissipate kinetic energy while reducing harmful arresting forces. This multi-functionality reduces the need for additional specialized components, thereby managing device complexity despite the presence of multiple closures.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3D
AI summary
An energy dissipating link (200) includes: a base (202) having first and second end portions (204,206); and a plurality of touch fasteners (208a-c) permanently coupled to the base, each of the plurality of touch fasteners releasably engageable with at least one other of the touch fasteners. The plurality of touch fasteners (208a-c) is arranged on the base to form first and second closures (212a-b) including engagements between two or more of the plurality of touch fasteners. The plurality of touch fasteners (208a-c) is configured such that: in response to a tensile load applied to the base, the engaged touch fasteners of the first closure (212a) are loaded in shear along a shear plane (218); and in response to a tensile overload condition causing shear displacement of the touch fasteners of the first closure (212a), the engaged touch fasteners of the second closure (212b) are subjected to a peel load.