Sinusoidal Tear Element Webbing for Fall Arrest Energy Absorption
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Solution Overview
Problem
Current tear away shock absorbers in personal fall arrest systems fail to consistently meet the dynamic drop test standards set by American and Canadian National Standards, posing a risk to worker safety.
Innovation Solution
A two-ply webbing energy absorber with sinusoidal exterior and interior tear elements made of high tenacity polyester yarns, designed to decelerate a falling worker by tearing under load, is integrated into the lanyard system, ensuring compliance with safety standards through controlled elongation and peak load management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a tear away shock absorber is designed to be lightweight and compact, then portability and ease of integration are improved, but the ability to consistently pass dynamic drop test standards deteriorates
Solution Approach 1:
The shock absorber is divided into two separate webbing layers (first and second webbing) with tear elements positioned between them. This segmentation allows each layer to contribute independently to energy absorption while maintaining overall compactness and lightness.
Solution Approach 2:
The invention uses composite construction with two webbing layers and tear elements made of high tenacity polyester yarns. The combination of these materials creates a lightweight yet reliable structure that consistently meets dynamic drop test standards.
2Loss of energy
If tear elements are designed to tear away under load to absorb energy, then shock absorption is improved, but control over peak load and elongation parameters deteriorates
Solution Approach 1:
Tear elements are strategically positioned at specific locations between the webbing layers where they will selectively tear under load. This localized placement ensures controlled energy absorption while maintaining precise control over peak load (not exceeding 900 pounds) and elongation (not exceeding 42 inches) parameters.
Solution Approach 2:
The tear elements are designed with specific physical properties and dimensions that determine their tearing behavior. By controlling the parameters of the tear elements (material composition, dimensions, positioning), the invention achieves both effective energy absorption and precise control over load and elongation parameters to meet safety standards.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively decelerates a falling worker's descent, meeting the dynamic performance standards by maintaining peak loads under 900 pounds and elongation within 42 inches, enhancing safety and compatibility with existing systems.
Implementation Method 1
The tear elements are designed to tear away decelerating the workers rate of fall and thus remove the shock at impact
Data Source
AI summary
An energy absorber for use in a personal fall arresting system. The absorber contains upper and lower webbings which are each two ply members. The back ply of the upper webbing is mounted adjacent to the face ply of the lower webbing with said webbing being of about equal length and width. Exterior tear elements run back and forth sinusoidally between attachment points on the face ply of the upper webbing and the back ply of the lower webbing. Interior tear elements run back and forth sinusoidally between attachment points on the back ply of the upper webbing and the top ply of the lower webbing.