Abstract:
A non-rigid head guard assembly that provides protection against head collisions. The head guard is circular with a narrower section at the forehead and a wider section at the rear to protect the back of the head. The head guard, at the sections in contact with the temple area of the head and the back of the head, is reinforced with an additional layer of foam. The exterior of the assembly is made of breathable and moisture wicking fabric. The interior protective element consists of either a single layer of viscoelastic polyurethane foam or a dual layer viscoelastic polyurethane foam separated by a thin layer of semi-dry lubricant, which is a low friction material, for enhanced wear and corrosion protection.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority under 35 U.S.C. §119 to U.S. Provisional Application No. 61/821,507, entitled “Protective Head Guard,” filed May 9, 2013, which is hereby incorporated by reference in its entirety as part of the present disclosure. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to athletic protective gear and more specifically, to a protective head guard made of non-rigid material, for use in sports such as soccer, rugby, handball, lacrosse, skiing, snowboarding, figure skating, roller hockey, ice hockey, field hockey, and other sports where a non-hard shell protective headgear would be beneficial. 
     BACKGROUND OF THE INVENTION 
     Head injuries from contact sports widely recognized as a serious health issue. High-impact collisions can sometimes result in concussions, which the Centers for Disease Control and Prevention defines as a “type of Traumatic Brain Injury (TBI) caused by a bump, blow, or jolt to the head that can change the way your brain normally works.” There is a growing body of scientific and clinical evidence linking concussions and long-term impairment of cognitive functions. Repeat concussions are linked to Chronic Traumatic Encephalopathy (CTE), a progressive neurodegenerative disease that has Alzheimer-like symptoms. In a 2012 study, autopsy of 85 deceased brain donors who suffered multiple brain injuries revealed signs of CTE in 65 of 85 donor brains. Symptoms of CTE start with headaches and problems with concentration in the early stages, followed by depression, aggression, explosive anger and short-term memory loss. More serious cognitive impairments occur later, and eventually result in full-blown dementia. 
     In sports such as American football, hockey, and men&#39;s lacrosse, hard helmets are used to reduce the impact of collisions. However, in other sports such as soccer, women&#39;s lacrosse, rugby, and volleyball, where hard helmets are not worn, or are rarely worn, options for protecting against head-to-head collision, repeat ball-to-head impact, and collision with the ground or goal posts, are still limited. 
     SUMMARY OF THE INVENTION 
     The present disclosure is directed to a head guard assembly that can reduce the force of impact from a collision, in a way that reduces both linear acceleration and angular acceleration experienced by the head. By reducing both angular and linear acceleration, the head guard helps reduce the risk of concussion from a traumatic head impact. 
     A non-rigid head guard assembly, constructed in accordance with the invention provides superior protection against head collisions. The head guard is circular with a narrower section at the forehead and a wider section at the rear to protect the back of the head. The head guard, at the sections in contact with the temple area of the head and the back of the head, is reinforced with an additional layer of foam. The exterior of the assembly is made of breathable and moisture wicking fabric. The interior protective element consists of either a single layer of viscoelastic polyurethane foam or a dual layer viscoelastic polyurethane foam separated by a thin layer of semi-dry lubricant, which is a low friction material, for enhanced wear and corrosion protection. The purpose of the separation is to enable concentric rotation between the two layers. The purpose of such a rotational system is to deflect the force of the impact away from the direction of the impact. The foam and the exterior fabric assembly are attached together via sewing and breathable hot-melt film or other adhesives to fix fabric to foam. The polyurethane foam is optimized to provide a consistent impact absorption property at various temperature ranges of soccer playing conditions, both indoor and outdoor, and throughout the year. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a right side perspective view of an embodiment of the head guard assembly of the present invention; 
         FIG. 2  is a rear perspective view thereof; 
         FIG. 3  is a front perspective view thereof; 
         FIG. 4  is a left side perspective view thereof; 
         FIG. 5 a    is an exploded front view of an embodiment of a dual layer foam composition of the head guard assembly of  FIG. 1 ; 
         FIG. 5 b    is an exploded rear view of the dual layer foam composition of the head guard assembly of  FIG. 1 ; 
         FIG. 5 c    is an exploded perspective view showing layers of the dual layer foam composition; 
         FIG. 5 d    is a front view of the dual layer foam composition; 
         FIG. 5 e    is a top view of the dual layer foam composition incorporated in an embodiment into the head guard assembly of the present invention; 
         FIG. 5 f    is a bottom view of the dual layer foam composition incorporated in an embodiment into the head guard assembly of the present invention; 
         FIG. 6 a    is another left side perspective view of the head guard assembly of the present invention; and 
         FIG. 6 b    is another right side perspective view of the heard guard assembly of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to  FIGS. 1 through 6 , there is shown an embodiment of a head guard assembly of the present invention, which will be designated hereinafter as reference numeral  100 , and embodiments of features of the head guard assembly  100 . The head guard assembly  100  is of a circular construction in the shape of a ring and may wrap around a user&#39;s head, similar to a headband. The front  101  of the head guard assembly  100  is tapered, covering just the forehead. Included on the front  101  of the head guard assembly  100  are a front pad  102 , a left temple pad  104 , and a right temple pad  106 . The front pad  102  extends around slightly more than half of the circumference of the head guard assembly  100  and includes creased junctions  126 ,  128  at opposite ends. The right temple pad  106  and the left temple pad  104  are positioned adjacent to the respective junctions  126 ,  128  and extend from the bottom of the head guard assembly  100  partially towards the top of the head guard assembly  100 . The right temple pad  106  and the left temple pad  104  may further include an additional layer of foam to provide additional protection to the temple area like the foam assembly  122  for elements of the rear  110  of the head guard  100  that will be described below. 
     The rear  110  of the head guard assembly  100  covers a wider area, including the back of the head H of the wearer of the head guard assembly  100  and the top of the neck N to provide comprehensive protection against head-to-head collisions as well as collisions with the ground. As illustrated in  FIGS. 6 a  and 6 b   , the rear  110  of the head guard assembly  100  includes a main upper pad  112 , a second upper pad  114 , a main lower pad  116 , and a second lower pad  118 . The second upper pad  114  extends from the junction  126  around the rear  110  of the head guard assembly  100  to the opposing junction  128 . The second upper pad  114  and the second lower pad  118  are reinforced with an additional layer of foam forming a foam assembly  122 , similar to the temple pads  104 ,  106 . 
     The foam assembly  122  as shown in  FIGS. 5 a -5 f    includes a main foam layer  136  that is arranged adjacent to a first side of top foam layers  134 . 
     The preferred fabric of the heard guard, which encompasses the entire head guard assembly  100 , is a woven breathable fabric  120  made of synthetic fibers. To secure the elements of the front  101  and rear  110  of the head guard assembly  100  that can include single layers of foam and multiple layers of foam (i.e., the foam assembly  122 ) between layers of the breathable fabric  120 , the fabric  120  wraps around the single layers of foam (e.g., the front pad  102 , the main upper pad  112 , the main lower pad  116 ) and the multiple layers of foam that are part of the foam assembly  122  (i.e., the temple pads  104 ,  106 , the second upper pad  114  and the second lower pad  118 ), and the layers of the fabric  120  are stitched together. In an embodiment, and thermoplastic polyurethane film or other adhesives  130  aid to fix the layers of fabric  120  to foam by gluing the foam to the layers of fabric  120  using a heat press (i.e., hot melting). Additional webbing material (i.e., mesh layers  132 ) may be added for decorative purposes. As shown in  FIGS. 5 a , 5 b , 5 c  and 5 d   , the mesh layers  132  can be added as well between the layers of fabric  120 . 
     The foam  102 ,  104 ,  106 ,  112 ,  114 ,  116 ,  118  used in the head guard assembly  100  has been optimized to provide consistent impact protection at a wide temperature range that simulates extreme soccer playing conditions throughout the year. For testing, the American Society for Testing and Materials (ASTM) F2439 “Specification For Headgear used in Soccer” was used to measure impact absorption of the head guard at room temperature (22° C.), high temperature (50° C.), and low temperature (−14° C.). 
     The foam of the head guard assembly  100  is viscoelastic foam. The viscoelastic foam deforms when a force is applied thereto. The amount of deformation is dependent on three factors: (1) the amount of force applied; (2) the duration of the application of the force; and (3) the temperature of the environment of the foam. 
     Viscoelasticity arises from the formation and breaking of non-covalent bonds in the underlying material, the time-dependent strain either increases or decreases with temperature. This poses a challenge creating viscoelastic foam that acts consistently across a wide temperature range. At high temperature, as non-covalent bonds are broken, the time-dependent strain property is decreased. This results in softening of the material, and thus decreasing protection against impact. At low temperatures, more non-covalent bonds are formed, thus increasing the time-dependent strain property. This results in the stiffening or hardening of the material, which can also decrease impact protection, as the cushioning property of the material is lost. Additionally, the material can become so stiff that it could not be worn on the head. 
     The head guard assembly  100  incorporates viscoelastic foam that exhibits consistent impact absorption properties, and is pliable enough to form around one&#39;s head, at the three temperatures mentioned above. 
     On impact absorption, the optimized foam will absorb at least 30% of the impact force (as outlined in the ASTM testing standard) at all three temperatures. The consistent level of impact absorption allows the same head guard assembly  100  to be used both in the summer and the winter. 
     One factor providing this property is tuning the glass-transition temperature (i.e., the temperature in which the molecules changes between solid and liquid state) of the foam to be higher than the human body temperature, i.e., above 40° C. This allows the foam to remain at the uniform solid state below 40° C. The result of this higher glass transition temperature is to give the foam a more constant time-dependent strain rate below the transition temperature. By tweaking the foam density, the glass transition temperature, and the cure rate, an optimized foam for the head guard assembly  100  is achieved. 
     Optionally, a layer of low friction material such as TEFLON® (i.e., a polymer with slippery, nonstick properties) or another type of lubricant may be placed between the top foam layers  134  and the main foam layer  136  comprising the foam assembly  122 . This would allow for concentric rotation of the two foam layers  134 ,  136 . The purpose of this mechanism is to deflect the impact force vector away from the direction of the original impact. This allows an additional source of impact dissipation. More importantly, by allowing the foam layers  134 ,  136  to rotate against each other, the angular acceleration experienced by the head of the user may be reduced. Scientific studies have suggested that angular acceleration of the head is linked to concussions. Thus, reducing angular rotation may reduce the risk of concussions in users of the heard guard assembly  100 . Additionally, the low-friction material layer is perforated to facilitate breathability, cooling and sweating, which allows for improved temperature management. 
     For the rear  110  and sides of the head guard assembly  100 , there is also a third external-facing foam to provide additional protection. 
     The accompanying drawings only illustrate several embodiments of a heard guard and its respective constituent parts, however, other types and styles are possible, and the drawings are not intended to be limiting in that regard. Thus, although the description above and accompanying drawings contains much specificity, the details provided should not be construed as limiting the scope of the embodiments but merely as providing illustrations of some of the presently preferred embodiments. The drawings and the description are not to be taken as restrictive on the scope of the embodiments and are understood as broad and general teachings in accordance with the present invention. While the present embodiments of the invention have been described using specific terms, such description is for present illustrative purposes only, and it is to be understood that modifications and variations to such embodiments, including but not limited to the substitutions of equivalent features, materials, or parts, and the reversal of various features thereof, may be practiced by those of ordinary skill in the art without departing from the spirit and scope of the invention.