Tolerance Ring Energy Absorber for Fall Arrest Systems
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Solution Overview
Problem
Existing fall arrest systems face challenges in effectively absorbing energy during fall events, particularly in systems that rely on rotational components, where energy absorption is limited by the torque threshold and the materials used, such as coiled plastically deformable absorbers, which can be costly and inefficient.
Innovation Solution
The use of a tolerance ring as a resilient element providing an interference fit between rotational components, allowing relative rotational motion when a predetermined torque level is reached, thereby absorbing energy through the torque threshold characteristic and providing an energy-absorbing braking effect, while also accommodating minor variations in component diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If coiled plastically deformable energy absorbers are used, then energy absorption capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent employs a simple friction brake mechanism with a drum, brake shoes, and actuator windings that can be easily manufactured and replaced. This disposable-like approach uses inexpensive components rather than complex plastically deformable absorbers, achieving energy absorption through friction while maintaining simplicity and low cost.
Solution Approach 2:
The invention replaces the mechanical plastically deformable energy absorption system with a friction-based braking system. Instead of relying on permanent deformation of metal components, the system uses friction between brake shoes and the drum surface to dissipate energy, substituting a simpler mechanical mechanism for a more complex plastic deformation system.
2Use of energy by moving object
If friction brake devices are used, then energy absorption is achieved, but heat generation and material wear occur
Solution Approach 1:
The patent incorporates an energy absorber device that activates during fall events to cushion the impact before excessive forces are transmitted to the user and anchor structure. The friction brake system with actuator windings provides controlled energy absorption that mitigates the harmful effects of sudden impact, preventing both heat generation and material wear by controlling the braking action within safe parameters.
3Manufacturing precision
If tolerance ring is used for interference fit, then manufacturing precision is improved, but energy absorption capability may be limited
Solution Approach 1:
The patent employs a dynamic friction brake system where the drum can rotate freely during normal operation but is capable of being braked when energy absorption is required. The actuator windings dynamically engage the brake shoes against the drum surface during fall events, providing variable energy absorption capability that adapts to the fall conditions while maintaining precise manufacturing tolerances through the tolerance ring interference fit.
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
This solution enables efficient energy absorption during fall events, controlling the payout time of safety lines and reducing the risk of injury by utilizing a cost-effective and adaptable energy absorption mechanism that can be integrated into various fall arrest system configurations.
Implementation Method 1
a resilient element providing an interference fit between a rotational component of the device and another component of the device
Implementation Method 2
the resilient element acting to resist the relative movement thereby absorbing energy
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5C
AI summary
A safety device for use in a fall arrest or fall safety system includes an energy absorber to absorb energy in the event of a fall or other impulse event. The energy absorber is a resilient element (such as a tolerance ring) providing an interference fit between a first component of the device and a second component of the device. In the event of a fall arrestor other impulse event, the first and second components effect movement relative to one another, the interference fit being overcome, and the resilient element/tolerance ring acting to resist the relative movement thereby absorbing energy.