Patent Publication Number: US-2018049501-A1

Title: Shear-thickening fluid cowl for cervical spine protection

Description:
BACKGROUND 
     When a soldier sticks his head out of cover, his helmet protects him from shrapnel and small-arms fire. Armoring of the helmet (typically with Kevlar, Twaron and/or Dyneema) prevents such projectiles from penetrating the helmet and wounding the soldier in the head. In the event of an impact from a high-powered rifle round, however, the helmet does not provide protection. Helmets are generally not made strong enough to protect against high-powered rifle rounds. This is partly to save weight, and partly because even if the helmet can protect against such a round, the energy delivered by the round&#39;s impact will snap the wearer&#39;s head back at high velocity, causing severe or fatal injury (typically, damage to or severing of the cervical spine, brain concussion, and/or muscle trauma). There is no real point in protecting against penetration by a high-powered rifle round if the helmet&#39;s user is killed anyway by a severed spine. 
     SUMMARY 
     This invention, Shear-Thickening Fluid Cowl for Cervical Spine Protection (hereinafter “Cowl”), consists of a cowl or hood filled with shear-thickening fluid. The cowl remains flexible under normal circumstances but becomes rigid when a high-impact shock is transmitted to it through the wearer&#39;s helmet. The rigid Cowl transmits the energy from the high-velocity rifle round&#39;s impact around and past the user&#39;s head and into an attached rear plate in the user&#39;s body armor. For soldiers wearing helmets capable of withstanding a high-powered rifle round, Cowl provides survivability that previous designs do not provide. The deficiency of earlier designs is discussed in Prior Art, below. 
     PRIOR ART 
     The following is a tabulation of some prior art that appears relevant: 
     
       
         
           
               
               
               
               
             
               
                   
               
               
                   
                 Kind 
                 U.S. Patents 
                   
               
               
                 Patent Number 
                 Code 
                 Priority Date 
                 Patentee 
               
               
                   
               
             
            
               
                 US20130296755 
                 A1 
                 2012 May 4 
                 Duncan, Hyde 
               
               
                 U.S. Pat. No. 6,701,529 
                 B1 
                 1999 Feb. 5 
                 Extrude Hone Corp. 
               
               
                 US20070149079 
                 A1 
                 2001 Aug. 27 
                 Sting Free Company 
               
               
                 US20060234577 
                 A1 
                 2003 May 19 
                 Norman Wagner 
               
               
                 US20080313791 
                 A1 
                 2005 Nov. 23 
                 Nagely Scott W 
               
               
                 US20080172779 
                 A1 
                 2007 Jan. 19 
                 James Riddell 
               
               
                   
                   
                   
                 Ferguson 
               
               
                   
               
            
           
         
       
     
     The only prior art with any comparability to Cowl is US20130296755 A1, which uses shear-thickening fluid to prevent spinal injury in sports. Its main deficiency is that it is intended to stop the head from moving further after it is already in motion. This earlier approach does not conduct the energy directly from the helmet to the wearer&#39;s armored vest, and therefore will not prevent concussions, muscle damage, or cervical spine injury from high-velocity shock. As noted in the referenced patent, the earlier device is suitable for “numerous sports or other activities, such as in horse riding, [and] football.” 
     The key shortcoming of this design is that it is meant to stop an already moving head rather than conduct all the energy around and past the head. Indeed, it depends on the user&#39;s head to be in motion to activate the protective device. The design in US20130296755 A1 employs multiple tubes filled with non-Newtonian fluid. The tubes are twisted around each other inside a flexible connector. Violent movement causes the non-Newtonian fluid to solidify, which stiffens the connectors into rigid supports. This occurs after impact and depends on the head&#39;s motion itself to cause the shear in the dilatant that is required to cause hardening and arrest further motion. 
     Cowl is designed specifically so that the impact itself against the user&#39;s helmet (not subsequent user movement) rigidifies the dilatant and transfers energy to the user&#39;s armor backplate. 
     Cowl marks a substantial advance because it provides reason for the military to equip soldiers with bullet-proof helmets. A high-velocity head shot no longer needs to be lethal even if it is blocked by a helmet. 
     Dilatant fluids are already used for a variety of applications such as standalone armor or impact absorption (for example in U.S. Pat. No. 6,701,529 B1 and US20080172779), and vibration dampening (US20070145079 A1). The development of armors based on dilatant fluids (for example, US20060234577 A1), is a subject of much research. 
     SPECIFICATION 
     This invention consists of a cowl or hood filled with shear-thickening fluid that remains flexible under normal circumstances but becomes rigid when a high-impact physical shock is transmitted to it through the wearer&#39;s helmet. Shear-thickening fluid, also known as a dilatant, is a commercially available dass of non-Newtonian materials that change their mechanical properties in response to physical energy that creates “shear,” which is a kind of plastic deformation. The change, entailing increased viscosity, occurs in some fluids extremely rapidly. The dilatant crystallizes under stress and behaves more like a solid than a solution. Rigid baffles inside the Cowl contain this fluid in its liquid state. A high-velocity impact causes the fluid to become viscous to the point of rigidity. The rigid Cowl does not transmit the energy delivered by the high-velocity impact to the wearer&#39;s neck or head. Rather, the energy is transmitted by the now-rigid Cowl around the wearer to the rear plate of the wearer&#39;s armored vest. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagram showing the invention on a user in three-quarters profile. The images are:  1 , the invention, Cowl, which is attached to:  2 , the user&#39;s helmet and to:  3 , the user&#39;s body armor. 
       FIG. 2  is a rear view of the invention showing the Cowl as if it were transparent. The images are:  1 , the outline of Cowl;  2 , the user&#39;s helmet;  3 , the user&#39;s body armor;  4 , fasteners connecting the Cowl to the helmet and body armor. 
       FIG. 3  is a side view of the helmet-body-armor-Cowl configuration. The images are:  1 , the user&#39;s helmet;  2 , the user&#39;s body armor lapping onto the user&#39;s back;  3 , the side-view of Cowl;  4 , inter-baffle spaces for dilatant fluid;  5 , baffles;  6 , wire that transmits shock energy through Cowl and helps regulate baffle spacing;  7 , fasteners that attach Cowl to the helmet and body armor.