Helmet Shock Absorbing Layer With Independent Frusto-Conical Cells
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Solution Overview
Problem
Current shock absorbing materials in helmets, particularly multiple impact helmets, suffer from performance degradation after repeated impacts due to plastic deformation, and fail to adequately manage angular accelerations, which can cause significant injury despite focusing primarily on linear acceleration attenuation.
Innovation Solution
A shock absorbing layer comprising independently collapsible, hollow shock absorbing members with a closed perimeter wall featuring a diverging-converging profile and frusto-conical sections, allowing for effective absorption of both linear and angular impact loads without significant fluid flow restriction, and incorporating secondary shock absorbing members for enhanced energy management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shock absorbing elements are designed to withstand multiple impacts with little permanent deformation, then reliability is improved, but the material thickness in the impact zone reduces due to plastic deformation, increasing material density and making the material harder, which results in reduced energy management
Solution Approach 1:
The shock absorbing layer is divided into multiple independent cells rather than using a continuous material. Each cell can deform independently during impact, allowing the overall structure to absorb energy through controlled collapse of individual cells while maintaining integrity of the remaining cells for subsequent impacts.
Solution Approach 2:
The patent modifies the physical parameters of the shock absorbing elements by creating hollow cells with specific wall thicknesses and geometries. These parameter changes allow the cells to undergo elastic deformation and controlled collapse, providing energy absorption without the permanent hardening that occurs in traditional materials.
2Loss of energy
If the shock absorbing layer uses larger cells to contain sufficient fluid volume for impact resistance, then energy management is improved, but the coverage of the shock absorbing layer within the helmet is reduced, hindering achievement of proper all around protection
Solution Approach 1:
The shock absorbing system is segmented into numerous small cells distributed throughout the helmet interior. This segmentation allows sufficient total fluid volume for energy absorption while achieving complete coverage of the helmet's impact surfaces, solving the contradiction between cell size and coverage area.
Solution Approach 2:
The shock absorbing layer employs a porous cellular structure that provides both volume for fluid containment and extensive surface coverage. The cellular geometry allows the material to maintain low density while providing adequate fluid volume within each cell for effective impact energy absorption.
3Strength
If webbing is used to interconnect shock absorbing members, then structural integrity is improved, but lateral displacement during collapse is restricted and resistance to bending of tubular members increases, preventing adequate angular acceleration impact attenuation
Solution Approach 1:
The webbing that previously interconnected the shock absorbing members is completely removed from the design. The hollow cells stand independent of one another, allowing free lateral displacement and collapse during impact. This extraction of the webbing eliminates the restriction on angular acceleration attenuation while maintaining structural integrity through the inherent strength of the individual cell structures.
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 improved impact attenuation by optimizing the height-to-width ratio and wall thickness of shock absorbing members, effectively managing both linear and angular accelerations, thereby enhancing helmet protection and reducing the risk of injury from rotational forces.
Implementation Method 1
The shock absorbing members are hollow and defining a closed perimeter wall extending upwardly from the base plate to an open top end sized to cause negligible reduction of fluid flow exiting the shock absorbing member
Implementation Method 2
each of the shock absorbing members being independently and elastically collapsible to at least partially absorb an impact load on the helmet
Data Source
AI summary
The present shock absorbing layer for a helmet includes a base plate and a plurality of spaced apart, independently and elastically collapsible, shock absorbing members. These hollow shock absorbing members define a closed perimeter wall extending upwardly from the base plate to an open top end sized to cause negligible reduction of fluid flow exiting the shock absorbing member. The closed perimeter wall includes a first portion with opposed inner and outer surfaces each having the shape of a frustum, and a second portion with opposed inner and outer surfaces each also having the shape of a frustum. These inner surfaces are interconnected through relatively radially wider ends of their respective frustums to define an inner angle therebetween of less than 180 degrees. These outer surfaces are interconnected through relatively radially wider ends of their respective frustums to define an outer angle therebetween of greater than 180 degrees.