Constant-Force Impact Padding With Fluid Bleed-Out Compression
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Solution Overview
Problem
Current impact protection devices, such as helmets, are ineffective in reducing brain injuries due to their inability to apply a consistent force across varying impact velocities, leading to inadequate protection in both high and low impact scenarios.
Innovation Solution
A protective impact device with a compressible vessel and incompressible fluid that increases cross-sectional area and allows fluid to bleed out through orifices, maintaining a constant force during compression, regardless of impact velocity, by using a design with a monotonically increasing shape profile and one-way valves for fluid return.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If stiff padding is used for high impact speeds, then protection against bottoming out is improved, but effectiveness in lower impact speeds deteriorates due to excessive force application
Solution Approach 1:
The padding structure transitions from a static uniform density design to a dynamic progressive density design where the density increases progressively from the impact surface inward. This allows the padding to adapt its stiffness dynamically during compression - softer at initial contact for low-speed impacts, and progressively stiffer during deeper compression for high-speed impacts, thereby resolving the contradiction between protecting against bottoming out and avoiding excessive force.
Solution Approach 2:
The invention changes the physical parameter of density distribution within the padding material. By creating a gradient where density increases with depth from the impact surface, the padding exhibits varying local stiffness properties. This parameter change enables the same padding structure to provide appropriate resistance across a wide range of impact velocities, preventing both bottoming out and excessive force application.
2Ease of manufacture
If uniform density padding is used, then manufacturing simplicity is maintained, but effectiveness across varying impact velocities deteriorates
Solution Approach 1:
The invention applies local quality by creating regions of different density within the padding material. The density is not uniform but varies locally - lower density near the impact surface and progressively higher density toward the interior. This local differentiation allows each region to contribute differently to impact absorption, enabling the padding to adapt to various impact velocities while remaining manufacturable through techniques like progressive compression molding or layered material assembly.
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 reduces head accelerations by up to 50% compared to conventional foam padding, effectively absorbing kinetic energy and minimizing the risk of concussions across different impact speeds.
Implementation Method 1
effectively absorbing kinetic energy
Implementation Method 2
one or more one-way valves allow the fluid to return to the compressible vessel back into the compressible vessel after the compression
Data Source
AI summary
A protective impact device is provided that produces an approximately constant force during compression. The device distinguishes several structural features. First, the cross-sectional area in between two impact surfaces increases over the stroke distance when compression takes place. Second, a compressible fluid containing vessel, held in between two impact surfaces, defines an outer shape with a positive second derivative slope defined from one impact surface towards the other impact surface. Third, orifices allow the fluid to bleed out from the compressible vessel when an impact force causes compression of the protective impact device. The resulting approximately constant force scales more or less linearly with impact energy, regardless of impact velocity caused by the impact force. Applications include athletic equipment, automotive bumpers, aircraft landing gear, and any other application that would benefit from maximum energy absorption during an impact.