Low-Protrusion Safety Fastener for Ballistic Helmet
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Solution Overview
Problem
Existing ballistic helmet fasteners are prone to creating secondary projectiles due to their design, which compromises the helmet's ballistic safety by allowing external protrusions and increased weight, failing to effectively absorb ballistic threat energy without fracturing and forming additional projectiles.
Innovation Solution
A safety fastener with a low interior impact profile, featuring a conical engagement surface and a threaded body that absorbs ballistic threat energy by allowing the helmet shell to deform, preventing the fastener from forming secondary projectiles through controlled disengagement and energy dissipation, while maintaining a lightweight and compact design within the helmet's protrusion limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional screw and bolt fasteners are used to mount fitting equipment to the helmet shell, then the fitting equipment can be securely mounted, but the fastener creates external protrusions and increases weight that compromise ballistic safety
Solution Approach 1:
The invention extracts the protruding elements (bolt heads, nut exteriors) from the helmet interior space by designing a fastener where the engagement surface and retention features are contained within or flush with the helmet shell exterior, eliminating secondary projectile hazards while maintaining mounting security
Solution Approach 2:
The fastener design nests the retention features within the helmet shell structure, with the engagement surface positioned to receive fitting equipment without extending beyond the shell's ballistic protective envelope, thereby maintaining ballistic safety while achieving secure mounting
2Object-affected harmful factors
If overdimensioned fasteners are used to provide greater robustness against ballistic threats, then ballistic resistance improves, but weight and internal protrusion increase excessively
Solution Approach 1:
The invention applies local quality by concentrating fastener strength where needed (in the engagement surface geometry and material properties at the ballistic threat interface) rather than uniformly overdimensioning the entire fastener, achieving adequate ballistic resistance with minimized weight
Solution Approach 2:
The invention changes the geometric parameters of the fastener to create a low-profile design where the engagement surface area and retention features are optimized to provide necessary ballistic resistance while maintaining compact dimensions and low weight suitable for helmet applications
3Strength
If conventional fasteners are used with external engagement surfaces, then fitting equipment can be securely retained, but the fastener may fracture and form secondary projectiles during ballistic incursion
Solution Approach 1:
The invention converts the potential harm of fastener fracture into benefit by designing the engagement surface with progressive deformation characteristics that allow controlled energy dissipation through elastic and plastic deformation rather than catastrophic fracture, transforming a potential hazard into a protective mechanism
Solution Approach 2:
The invention provides beforehand cushioning by designing the engagement surface geometry to inherently absorb and dissipate ballistic threat energy through progressive deformation, creating a built-in energy management system that prevents fracture and secondary projectile formation before they can occur
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 fastener effectively absorbs ballistic threat energy, preventing the formation of secondary projectiles and meeting stricter weight and protrusion guidelines, achieving improved ballistic resistance without increasing the fastener's size or weight, as demonstrated by successful testing against 9 mm FMJ threats.
Implementation Method 1
The engagement surface is ramped to allow for progressive deformation and energy dissipation of the fitting equipment
Implementation Method 2
The engagement surface is ramped to allow for progressive deformation and energy dissipation of the fitting equipment
Implementation Method 3
The absorption of ballistic threat energy by the helmet shell prevents the fastener from forming a secondary projectile
Data Source
AI summary
A safety fastener for mounting fitting equipment such as suspension and retention systems onto a ballistic helmet. The nut portion of the fastener fits substantially within a grommet that is attached to a strap that forms part of the suspension or retention systems. The nut retains, rather than clamps, the grommet to the helmet. The grommet can be pulled off the nut. The pull-out force is less than the fastener fracture force. The configuration of the fastener allows ballistic threat energy to be absorbed by helmet deformation and delamination along with grommet pull-out to provide energy dissipation in stages which avoids the creation of secondary projectiles from the fastener itself.