Rate-Activated Helmet Suspension for High-Velocity Impact Protection
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Solution Overview
Problem
Current helmet technologies fail to provide adequate protection against high-velocity impacts and repetitive low-energy accelerations, which can lead to head and brain injuries, particularly in military and sports applications.
Innovation Solution
The implementation of rate-activated tethers (RATs) as energy-absorbing components in helmet suspension systems, which provide a steady force over long strokes and increase resistance with impact velocity, reducing peak accelerations and enhancing energy absorption efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If standard foam compression pads are used for impact protection, then energy absorption is provided, but peak accelerations are high and protection against high-velocity impacts is insufficient
Solution Approach 1:
The patent changes the fundamental parameter of energy absorption mechanism from compression (foam pads) to tension (RATs). This parameter change enables the suspension to provide steady force over long strokes while maintaining speed sensitivity, thereby reducing peak accelerations and improving energy absorption efficiency simultaneously.
Solution Approach 2:
The RAT suspension system is designed to be dynamic and speed-sensitive, adjusting its resistance based on impact velocity. This dynamic behavior allows the system to provide optimal protection across a range of impact conditions, resolving the contradiction between reducing acceleration and absorbing energy efficiently.
2Ease of operation
If traditional suspension systems are used, then helmet fit is maintained, but head accelerations during impact are not sufficiently reduced
Solution Approach 1:
The patent segments the suspension system into multiple RAT elements distributed around the helmet interior. This segmentation allows the system to maintain proper helmet fit through distributed support while providing comprehensive acceleration reduction from multiple impact directions simultaneously.
3Force
If foam compression pads are used for energy absorption, then impact protection is provided, but the stroke length is limited and peak forces are high
Solution Approach 1:
The patent inverts the traditional approach by using tension-based energy absorption instead of compression. RATs extend during impact rather than compress, enabling much longer stroke lengths while maintaining lower peak forces. This inversion resolves the contradiction between force magnitude and stroke duration.
4Shape
If helmet geometry is constrained, then wearability is improved, but protection against high-velocity impacts cannot be achieved
Solution Approach 1:
The patent changes the energy absorption parameter from compression to tension, enabling RATs to achieve longer effective stroke lengths within the same geometric constraints. This parameter change allows high-velocity impact protection to be achieved without altering helmet external geometry, maintaining wearability while improving protection.
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
RATs significantly decrease head accelerations by 50% compared to standard suspension systems, reducing the likelihood of head and brain injuries and offering improved protection across a range of impact conditions.
Implementation Method 1
Because RATs absorb energy in tension, the present embodiments include concepts for transmitting loads inside the helmet to RATs located outside of the helmet shell
Implementation Method 2
The RATs provide two key features that are ideal for an energy absorber: (1) steady force over long strokes, and (2) a stroke force that increases with increasing impact velocity
Data Source
AI summary
Impact energy absorbing devices, in some embodiments, may be configured as a helmet having suspension elements employing “rate activated tethers” (RATs), a speed-sensitive flexible strapping material. The RATs are configured to suspend a helmet shell on the head of a wearer, so that impact to the helmet causes extension of the RATs. The RATs provide for: (1) steady force over long strokes, and (2) a stroke force that increases with increasing impact velocity. Standard impact testing of a helmeted headform shows that the RAT suspension decreases head accelerations by 50% relative to a standard suspension system. This decrease in head acceleration is expected to lead to a reduced likelihood of brain and head injury. Because the RATs absorb energy during tensile extension, they offer increases in energy absorption efficiency. These RAT suspensions can potentially replace or complement existing helmet pad and suspension systems in military, sports, and industrial safety-wear.