Abstract:
A football helmet is disclosed that includes a shell constructed of fiber reinforced epoxy resin, a liner made from expanded polypropylene, an impact absorbing layer situated between the liner and the shell, and a face guard. The impact absorbing layer is constructed from either expanded polypropylene or a viscoelastic polymer encased in a suitable thin yet resilient and elastic membrane. An optional impact absorbing band is also shown disposed around the inner periphery of the liner and encircling the player&#39;s head. The impact absorbing band serves to reduce impact forces occurring from side helmet impact with objects or players.

Description:
FIELD OF THE INVENTION 
     This invention relates in general to protective head gear and more specifically to football helmets. 
     BACKGROUND OF THE INVENTION 
     Helmets have long been worn in the sport of football to protect a player&#39;s head from injury resulting from impact with other players, ground impact, or impact with objects on or off the field. Recent prior art helmets typically include an outer shell made from durable plastic materials, a liner made from a shock absorbing material, a face guard and a chin strap which also functions in some designs as a chin protector. Helmet liners have taken several forms over the years, including encased foam padding, fluid filled jackets or pockets, air inflated bags lining the inner surface of the helmet and other design approaches. 
     Some recent patents directed to football helmets, such as U.S. Pat. Nos. 7,240,376, 6,934,971 and 7,036,151, all to Ide et al., have focused more on jaw protection, ear protection and improved face guard features without any notable changes in the shock absorbing liner designs. In general though, the overall configuration, design and shape of a football helmet has remained relatively unchanged over an extended period of time. 
     It is well recognized that no helmet can completely prevent injuries to persons playing the sport of football. The very nature of football is quite physical with much emphasis placed on strength and speed of the players. As players have increased their strength and speed, corresponding improvements in safety equipment, specifically helmets, has not taken place. Shock attenuation and impact force absorption are of foremost importance in the design of a football helmet. 
     Serious concerns have been raised in recent years regarding concussion injuries suffered by athletes while playing football and the long term affect such brain injuries have on the mental and physical health of those suffering such injuries. Some commentators suggest there may be significant consequences for continuing to play football before recovery from a concussion injury has taken place. Later life cognitive difficulties suffered by former football players are now being associated with concussion injuries received while playing football. Recently, researchers found the players were three times more likely to die from Alzheimer&#39;s, Parkinson&#39;s or Lou Gehrig&#39;s disease than the general population. 
     Given the recent media coverage of high profile football players who received concussion injuries while playing football and have later in life suffered from maladies and diseases of the brain resulting in abnormal life experiences and behavior, it is abundantly clear that more attention and effort should be directed to protecting players from such injuries. 
     In view of elevated attention concussion injuries are receiving in the media in relation to football, and in particular the long term negative impact on lives, any new developments in football helmet designs that improve the impact absorption or impact attenuation characteristics of a football helmet and lessen the forces impacting the head of a player are urgently needed. 
     SUMMARY OF THE INVENTION 
     A football helmet according to one aspect of the present invention includes a shell having an inner surface, an outer surface, an opening over the face area of the wearer, a crown area and wherein the shell is constructed of fiber reinforced epoxy resin and adapted to receive an athlete&#39;s head therein, an energy absorbing layer situated adjacent the inner surface of the shell and extending over the crown area of the shell, a liner having an outer surface conforming with the inner surface of the shell and the energy absorbing layer adjacent the inner surface of the shell and an inner surface closely conforming to the head of the wearer, the liner disposed within the shell such that the energy absorbing layer is situated between the liner and the shell in the crown area of the shell, the liner having a substantially uniform thickness and fabricated from expanded polypropylene, a face mask attached to the shell over the face area of the shell, and wherein the energy absorbing layer has a higher compressive strength than the compressive strength of the liner. 
     One object of the present invention is to provide an improved football helmet. 
     Another object of the present invention is to provide a football helmet that is lighter than prior art helmets. 
     Still another object of the present invention is to provide a football helmet that includes improved impact attenuation and shock absorbing features. 
     Yet another object of the present invention is to significantly reduce impact forces that are transmitted through a football helmet to the head of the player wearing the helmet. 
     These and other objects of the present invention will become more apparent from the following description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front elevational view of a football helmet according to one aspect of the present invention. 
         FIG. 2  is a bottom view of the football helmet of  FIG. 1 . 
         FIG. 3  is an exploded perspective view of the helmet of  FIG. 1 . 
         FIG. 4  is an exploded side view of the helmet of  FIG. 1 . 
         FIG. 5  is a plan view of the energy absorbing layer shown. 
         FIG. 6  is a plan view of an alternative energy absorbing layer. 
         FIG. 7  is a side view of the helmet shell depicting areas wherein additional reinforcing material are applied. 
         FIG. 8  is a plan view of the helmet shell depicting areas wherein additional reinforcing material are applied. 
         FIG. 9  is a plan view of the reinforcing material used to construct the helmet shell with an enlarged view of the fiber makeup. 
         FIG. 10  is an exploded perspective view of another embodiment of a football helmet according to the present invention. 
         FIG. 11  is a bottom view of another embodiment of a football helmet according to the present invention. 
         FIG. 12  is a perspective view of the energy absorbing band shown in  FIG. 11 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated devices, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     Referring now to  FIGS. 1 and 2 , a football helmet  10  according to one aspect of the present invention is shown.  FIG. 1  is a front elevational view and  FIG. 2  is a bottom view of helmet  10 . Helmet  10  includes a shell  12 , a face guard or face mask  14 , an energy absorbing liner  16 , jaw pads  18 , and face guard connectors  20 . Face guard connectors  20  and screws  24  secure face guard  14  to shell  12 . Face guard connectors  20  are secured to shell  12  by screws  24  and nuts (not shown) situated on the inner surface of shell  12 . Jaw pads  18  are attached to shell  12  using snap connectors or hook and loop fasteners (not shown). Chin strap snaps  26  are attached to shell  12  by threaded nuts (not shown) situated on the inner surface of shell  12  that engage a threaded portion of snaps  26  which extends through shell  12 . Ear apertures  28  in shell  12  are situated over the player&#39;s ears and allow sound waves s to readily pass therethrough. Fasteners for attaching face guards, jaw pads and chin straps to football helmets are well known in the art. 
     Shell  12  is relatively thin (typically less than one-eighth inch or less than 3 mm thick) and constructed of fiber reinforced epoxy resin formed in a shape that is generally conforming with yet larger than a human head. Shell  12  includes a face opening  13  and a head opening  15 . Shell  12  is thinner than prior art helmets and weighs substantially less than prior art shells made from polycarbonates or other known plastic materials. Liner  16  is fabricated from expanded polypropylene (EPP) and has an inner surface  16   a  that closely conforms with the general external shape of a human head. The inner surface of liner  16  is covered with a moisture wicking or moisture absorbing cloth material  17  to absorb perspiration from the player&#39;s head. The outer surface of liner  16  is shown in more detail in  FIG. 3  wherein an energy absorbing layer is also shown in more detail situated between shell  12  and liner  16 . Fitment pads  22  are attached to liner  16  about the inner periphery of liner  16  at multiple locations to achieve a comfortably snug fit of helmet  10  on a football player&#39;s head. Fitment pads  22  are made from fabric encased resilient foam padding material and are attached using adhesives, hook and loop fasteners or the like or other attachment means well known in the art. Fitment pads  22  are available in various thicknesses to accommodate varying head sizes within liner  16 . In order to accommodate a large range of head sizes, liner  16  may also be fabricated in a variety of thicknesses and in combination with various sized fitment pads all sizes of human heads are accommodated within helmet  10 . 
     Liner  16  is preferably constructed with external dimensions along the head opening  13  and face opening  15  of shell  12  that are slightly larger than the inner dimensions of shell  12  to create a slight interference fit within shell  12 . The process for inserting liner  16  within shell  12  includes slightly compressing liner  16  toward the middle at the edges thereof for installation into shell  12 . Liner  16  is retained within shell  12  as a result of the subsequent resilient expansion of liner  16  against the inner surfaces of shell  12 . Alternatively, liner  16  may be constructed with external dimensions in the face and head openings to be an exact fit to the inner surfaces of shell  12  and liner  16  is then attached to the inner surfaces of shell  12  using contact adhesive or the like. 
     Liner  16  is fabricated from expanded polypropylene since it is a highly versatile closed-cell bead foam or foam form of polypropylene that provides a unique range of properties, including outstanding energy absorption, multiple impact resistance, thermal insulation, buoyancy, water and chemical resistance, exceptionally high strength to weight ratio and 100% recyclability. EPP has very good impact characteristics due to its low stiffness; this allows EPP to resume its shape after impacts. EPP foam possesses superior cushioning properties, is able to absorb kinetic impacts very well without breaking, retains its original shape, and exhibits memory form characteristics which allow it to return to its original shape in a short amount of time. Polypropylene, in general, is not only resilient but also resistant to most solvents and glues. 
     Referring now to  FIGS. 3 and 4 , a perspective and side elevational exploded view of helmet  10  are shown, respectively, depicting shell  12 , liner  16  and energy absorbing layer  30 . During assembly of shell  12  and liner  16 , energy absorbing layer  30  is situated in recessed area  16   b  of liner  16 . The dimensions of recessed area  16   b  are such that layer  30  is in contact with the recessed external surface area  16   b  and the inner surface of shell  12 . Liner  16  is shown in  FIGS. 3 and 4  with moisture wicking material  17  removed. Shell  12  is shown with jaw pads  18  removed to more clearly illustrate the assembly process of inserting liner  16  and layer  30  within shell  12 . Layer  30  is a resilient membrane with a plurality of energy absorbing nodules suspended therein. The energy absorbing material in layer  30  has a compressive strength greater than the compressive strength or impact attenuation property of the expanded polypropylene of liner  16 . Peripheral surface  16   c  of liner  16  is compressed slightly to enable insertion of liner  16  within shell  12 . Face guard  14  and ear apertures  28  are also shown in  FIGS. 3 and 4 . 
       FIGS. 5 and 6  illustrate two different variations for energy absorbing layer  30  presently available, though other geometric arrangements are also contemplated. Energy absorbing layer  30  consists of a flexible resilient membrane  30   a  that encases an array of viscoelastic polymer material  30   b  into pockets within membrane  30   a . Layer  30  is produced by Impact Innovative Products of 127 Industry Blvd., Irwin, Pa. 15642 and referred to as Zoombang® impact attenuation material by the Impact Innovative Products.  FIG. 5  depicts one version of energy absorbing layer  30  having an array of hexagonal pockets of the viscoelastic polymer.  FIG. 6  depicts an alternate configuration for energy absorbing layer  31  which includes an array of elongated rounded rectangular pockets  31   b  of the viscoelastic polymer suspended in resilient flexible membrane  31   a . The precise formulation of the Zoombang® material is presumably a trade secret of Impact Innovative Products. The general geometric configuration of resilient flexible layers  30  and  31  shown in  FIGS. 5 and 6 , respectively, are intended to be formed to and placed over the pseudo-spherical surface defined by the external surface of recessed portion  16   b  of liner  16  (see  FIGS. 3 and 4 ) such that the entirety of surface  16   b  is well covered and contacted by one side of layer  30  or layer  31 . It is also contemplated that a very thin layer of contact adhesive may be used to maintain layer  30  or  31  in position over recessed surface  16   b  when liner  16  and layer  30  are assembled into shell  12 . 
     Referring now to  FIGS. 7 and 8 , a side elevational view and a plan view of shell  12  are shown, respectively, with a number of areas defined by broken lines that depict locations wherein the amount of reinforcing material applied during fabrication of shell  12  will vary. In general, shell  12  includes four (4) layers of reinforcing mesh in area  12   a , three (3) layers of reinforcing mesh in area  12   b , and six (6) layers of reinforcing mesh in areas marked  12   c . The variation in reinforcing material layer count is directly related to the desired strength and amount of resiliency or stiffness desired for the noted regions. In area  12   b  over the brain it is desired that shell  12  have more “resilience” or “flex” upon heavy impact. Area  12   a  may be slightly stiffer in resilience, thus four layers are applied therein. Significant strength is desired in area  12   c  where face guards, jaw pads and chin straps are attached, thus six layers of reinforcing material are applied therein during fabrication of shell  12 . 
     Referring now to  FIG. 9 , a detailed view of the reinforcing mesh  32  encased in epoxy resin to fabricate shell  12  is shown. Mesh  32  includes preferably three different fiber types, namely, carbon fibers, fiberglass fibers and Kevlar® fibers. One combination of fibers that provides desirable strength characteristics along with resiliency and toughness includes a 40 (forty) percent carbon fiber, 40 (forty) percent Kevlar fiber and 20 (twenty) percent fiberglass fiber ratio woven into a mesh as shown in  FIG. 9 . Kevlar® fiber bundles  34 , carbon fiber bundles  36  and fiberglass fiber bundles  38  are cross woven as shown to fabricate mesh  32 . The Kevlar® fiber bundles  34  and carbon fiber bundles  36  in mesh  32  are larger in individual fiber count than the fiberglass fiber bundles  38  such that the approximate fiber makeup of 40% Kevlar®  fiber , 40% carbon fiber and 20% fiberglass fiber content is achieved. 
     Referring now to  FIG. 10 , another embodiment of a football helmet  50  according to the present invention is shown in a perspective exploded view. All aspects and components of helmet  50  are identical to those shown for helmet  10  with the exception of cap  52  which replaces energy absorbing layer  30 . Helmet  50  of  FIG. 10  is shown without jaw pads for convenience in illustrating the exploded view, but it is contemplated that jaw pads are included with helmet  50 . In addition, liner  54  is shown with moisture wicking cloth removed. Cap  52  occupies and completely fills the space between liner  54  and shell  56  when helmet  50  is assembled. The lower surface of cap  52  is formed to coincide precisely with the upper pseudo-spherical recessed surface  54   b  of liner  54  and the external upper surface of cap  52  conforms with the inner surface of shell  56 . Thus, cap  52  completely fills the void defined between shell  56  and liner  54 . Cap  52  is fabricated from EPP with a higher density than that of the EPP used to fabricate liner  54 . Thus, cap  50  has a higher energy absorbing capability or increased impact attenuation as a result of the higher density of the EPP therein. The density of the EPP used to fabricate liner  54  is typically between 2 and 4 pounds per cubic foot and the density for the EPP used in fabricating cap  52  is typically between 4 and 6 pounds per cubic foot though it is contemplated that other combinations of densities may be desirable to achieve specific impact attenuation results for the combination of liner  54  and cap  52 . For example, where players are young and smaller with less speed and strength abilities, lower densities of EPP for the liner and cap may be more appropriate. 
     It is foreseeable that liner  54  and cap  52  may be fabricated as a unitary liner by use of sophisticated EPP molding techniques that are presently known or may be developed in the future. If liner  54  and cap  52  are fabricated as a unitary liner then the outer surface of the unitary liner then conforms with the inner surface of shell  56 . The unitary liner includes an inner surface closely conforming to the head of the wearer. Further, the unitary liner would include a substantially uniform thickness and be fabricated from expanded polypropylene. The expanded polypropylene at the outer surface of the unitary liner up to a predetermined depth (corresponding with the volumetric area occupied by cap  52 ) is fabricated from a higher density EPP than the remainder of the liner. 
     Referring now to  FIGS. 11 and 12 , another embodiment of a football helmet having an additional impact attenuation feature according to the present invention is shown that is used in conjunction with either helmet  10  or helmet  50 .  FIG. 11  is a bottom view of either helmet  10  or helmet  50  depicting energy absorbing band  60  installed about the inner periphery of the helmet liner so that the player&#39;s head is encircled by band  60 .  FIG. 12  is a perspective view of energy absorbing band  60 . Band  60  is flexible and resilient as it is fabricated from energy absorbing material encased in a thin resilient flexible membrane. Band  60  is situated within the helmet and attached about the inner periphery of the helmet to provide side force impact attenuation for the player&#39;s head. Band  60  is disposed over fitment pads  22  and attached to pads  22  and helmet liner  16  or  54 . Energy absorbing band  60  is approximately 1 to 2 inches in height and has a higher compressive strength than liners  16  or  54 . Band  60  is fabricated from a viscoelastic polymer material such as Zoombang® material, previously discussed, and preferably encased in a moisture absorbing or moisture wicking cloth. Band  60  is attached to liners  16  or  54  and over fitment pads  22  by either adhesives or hook and loop fasteners (not shown), as is well known in the art. 
     Many different materials are known that have energy absorbing characteristics coupled with resiliency as exhibited by EPP and the substitution of such materials in the present invention is contemplated. Energy absorbing materials such as viscoelastic polymers having compressive strength or impact attenuation properties similar to the Zoombang® material are contemplated as substitutes therefore in the present invention. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description of the preferred embodiments, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.