Tolerance Ring Energy Absorber for Resettable Fall Arrest

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Solution Overview

Problem

Existing external energy absorbers in fall protection devices, such as those used in industrial environments, are non-resettable, prone to weather degradation, and limited to fabric materials, which are not as durable as metal or composite counterparts, and often positioned away from the user, increasing the risk of high stopping forces during falls.

Innovation Solution

An external energy absorber featuring a hub with an energy absorbing arrangement including an outer and inner ring, where at least one tolerance ring made of spring steel generates friction between the rings upon rotation, allowing for controlled energy absorption and user resettable design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fabric energy absorbing devices are used, then energy absorption is achieved, but durability and weather resistance deteriorate

Engineering Contradiction:
ImprovedurabilityVSAvoidweather degradation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the material parameter from fabric to metal (specifically aluminum or aluminum alloy), fundamentally altering the material properties to achieve superior durability and weather resistance while maintaining energy absorption functionality through controlled deformation of the metal ring

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The energy absorber utilizes composite construction with an inner ring and outer ring that can be made of different materials (e.g., aluminum inner ring with steel outer ring), combining the benefits of lightweight material with high-strength material to optimize both durability and energy absorption characteristics

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If non-resettable energy absorbers are used, then energy absorption is achieved, but ease of operation deteriorates

Engineering Contradiction:
Improvereset capabilityVSAvoidsingle-use limitation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention employs a dynamic, resettable mechanism where the metal ring can deform during fall arrest and then be manually reset to its original position, transforming the energy absorber from a single-use component to a reusable device that maintains operational reliability through multiple cycles

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Instead of discarding the energy absorber after single use, the invention enables recovery and resetting of the metal ring component, allowing it to be reused multiple times while maintaining energy absorption performance, thereby improving ease of operation and reducing replacement frequency

Inventive Principle:
Principle #34Discarding and recovering

3Force

If energy absorber is positioned away from user, then device complexity is reduced, but force increases

Engineering Contradiction:
Improvestopping forceVSAvoidpositioning arrangement
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The invention merges the energy absorber with the hub assembly by integrating the metal ring directly into the hub structure, eliminating the need for separate positioning arrangements and reducing device complexity while simultaneously reducing stopping force by positioning the energy absorption point closer to the user

Inventive Principle:
Principle #5Merging (Combining)

4Loss of energy

If friction-based energy absorption is used, then energy absorption efficiency is improved, but device complexity increases

Engineering Contradiction:
Improveenergy absorptionVSAvoidfriction mechanism
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The invention extracts the complex friction mechanism from the design and replaces it with a simpler metal ring deformation mechanism, achieving energy absorption through controlled plastic deformation of the metal rather than through complex friction-based systems, thereby reducing device complexity while maintaining energy absorption efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

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 provides a durable, resettable, and efficient energy absorption mechanism that reduces the impact of falls by generating controlled friction, improving user safety and reducing the risk of equipment snagging or failure, while being resistant to weather conditions.

Implementation Method 1

the at least one energy absorbing member is configured to generate friction between the outer ring and the inner ring upon rotation of the hub

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3562562B1Tolerance ring in external energy absorber
Publication Date: 2022.08.03 MSA TECHNOLOGY LLC
  • EP3562562B1 patent drawingFigure 1~2
  • EP3562562B1 patent drawingFigure 3
  • EP3562562B1 patent drawingFigure 4

AI summary

An external energy absorber may include a hub having a line associated therewith, the line including a first end directly or indirectly attached to the hub and a second end opposite the first end attached to a user, an energy absorbing arrangement directly or indirectly attached to the hub, the energy absorbing arrangement comprising an outer ring directly or indirectly attached to the hub, an inner ring directly or indirectly attached to a housing, and at least one energy absorbing member positioned between the outer ring and the inner ring, wherein the at least one energy absorbing member is configured to generate friction between the outer ring and the inner ring upon rotation of the hub, and the housing configured to hold the hub and energy absorbing arrangement.