Patent Application
20140331391
This invention relates generally to the field of athletic protective gear. More specifically, this invention involves 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.
Head injuries from contact sports are becoming 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's lacrosse, hard helmets are used to reduce the impact of collisions, However, in other sports such as soccer, women'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.
We present here an invention 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 this 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 2 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.
a is an exploded view of a dual layer foam composition of the head guard assembly;
b is an exploded view showing layers of the foam used for the present invention;
c is a front view of an illustration of the dual layer foam composition;
d is a top view of an illustration of the dual layer foam composition of an example of the head guard assembly of the present invention;
e is a bottom view of an illustration of the dual layer foam composition of an example of the head guard assembly of the present invention; and
With reference to
The rear of the head guard covers a wider area including the back of the head B of the wearer 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
The preferred fabric of the heard guard is a woven breathable fabric made of synthetic fibers. The fabric 120 wraps around the internal foam assembly 300 via stitching and also hot-melt thermoplastic polyurethane film or other adhesives to fix fabric to foam. Further, the outer fabric is glued to the foam pads using a heat press. Additional webbing material may be added for decorative purposes.
The foam pads used in the head guard 200 have 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 122 of the head guard 200 is viscoelastic foam. The viscoelastic foam deforms when a force is applied to the foam. The amount of deformation is dependent on three factors: the amount of force applied; the duration of the application of the force; and 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 200 incorporates viscoelastic foam 122 that exhibits consistent impact absorption properties, and is pliable enough to form around one'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 to be used 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 is achieved.
Optionally, a layer of low friction material such as Teflon or another type of lubricant may be placed between the two foam layers. This would allow for concentric rotation of the two layers of foam. 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 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 presently described heard guard. 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 skies of the head guard, 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.
This application claims the priority to U.S. Provisional Application No. 61/821,507, entitled “Protective Head Guard,” filed May 9, 2013.
| Number | Date | Country | |
|---|---|---|---|
| 61821507 | May 2013 | US |
