Helmet Rotational Limiter with Shelf and Spring Coupling
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Solution Overview
Problem
Conventional helmets with multiple energy management liners often fail to effectively attenuate rotational accelerations experienced by the head and brain due to reliance on small projections and friction, which can lead to unstable liner separation and inadequate energy absorption over time.
Innovation Solution
A helmet design featuring an outer liner with a shelf extending inward from its interior surface, slidably coupled to an inner liner through return springs, allowing for controlled rotation and energy absorption across a wider surface area, thereby stabilizing the inner liner and reducing rotational accelerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional helmets use small projections and friction between liners to reduce rotational energy, then the structure is simple, but the energy absorption is inadequate and liner separation becomes unstable
Solution Approach 1:
The inner liner is divided into multiple segments that can rotate independently relative to each other and to the outer liner. This segmentation allows rotational energy to be distributed across multiple interfaces, improving energy absorption effectiveness while maintaining structural manageability
Solution Approach 2:
A coupling mechanism with friction elements and mechanical interlocks serves as an intermediary between the inner and outer liners. This intermediary structure provides controlled friction and mechanical engagement to stabilize liner interaction during rotational impacts, addressing both reliability and complexity concerns
2Loss of energy
If conventional helmets allow liners to rotate against each other for energy absorption, then rotational energy can be reduced, but the liners tend to separate and reduce helmet stability
Solution Approach 1:
The coupling mechanism incorporates friction elements that provide continuous feedback force between the liners during rotation. This feedback mechanism maintains controlled interaction between liners, allowing energy absorption while preventing complete separation and maintaining helmet stability
Solution Approach 2:
The coupling mechanism uses composite construction with friction materials and mechanical elements working together. This composite approach enables simultaneous energy absorption through friction and stability maintenance through mechanical interlocking
3Loss of energy
If conventional helmets use projections that break or deform for energy absorption, then energy can be absorbed, but the absorption happens over a short period and does little to attenuate rotational accelerations
Solution Approach 1:
The coupling mechanism employs dynamic friction elements that progressively engage during rotational impact. This dynamic interaction extends the duration of energy absorption by maintaining controlled friction forces throughout the rotation event, rather than relying on sudden projection failure
Solution Approach 2:
The friction characteristics of the coupling mechanism are designed to change parameters during impact - maintaining consistent friction forces over an extended time period. This parameter control extends the energy absorption duration and improves rotational acceleration attenuation
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 design effectively attenuates rotational energy over a longer period, preventing liner separation and enhancing head protection by distributing energy absorption across a stronger, wider portion of the liner, resulting in improved stability and reduced rotational acceleration/deceleration.
Implementation Method 1
The at least one return spring biases the inner liner toward the first position
Implementation Method 2
a portion of the edge of the inner liner is in contact with a portion of the arresting surface of the shelf in response to movement of the outer liner relative to the inner liner caused by an impact to the helmet
Data Source
AI summary
A helmet for protection during an impact, wherein an inner liner may slidably couple to the outer liner through at least one return spring. The outer liner includes an interior surface with a shelf extending inward. The shelf includes an arresting surface. The inner liner has an exterior surface, an interior surface and an edge connecting the exterior surface to the interior surface. The edge faces the arresting surface of the shelf. The inner liner is slidably movable relative to the outer liner between a first position in which the edge of the inner liner is separated from the arresting surface of the shelf by a first gap, and an arrested position in which a portion of the edge of the inner liner is in contact with a portion of the arresting surface of the shelf.