Abstract:
A helmet is comprised of: a stiff outer shell and an inner liner adapted to be fitted to a wearer&#39;s head. A shock absorbing layer is located between, and connected to, the stiff outer shell and the fitted inner layer. The shock absorbing layer is adapted to allow the outer shell to flex rotationally relative to the inner layer in order to cushion a rotational force applied to the outer shell. The shock absorbing layer is adapted to allow the outer shell to move linearly relative to the inner liner in order to cushion a linear force applied to the outer shell.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates generally to a protective head product. More particularly, the invention relates to a helmet that may reduce rotational impacts to the wearer. 
       BACKGROUND OF THE INVENTION 
       [0002]    Concussions and other head injuries are a major concern for athletes and others participating in activities where the head may be subjected to force. Concussions are a form of traumatic brain injury (TBI) and can range in severity from mild to life threatening. It is now known that concussions are more than temporary impairments of neurological functions which resolve spontaneously. Concussions may have long lasting effects. 
         [0003]    Moreover, repetitive concussions are extremely serious and can result in permanent structural changes to the brain and may be potentially fatal. Repetitive concussions have also been linked to Chronic Traumatic Encephalopathy (CTE)—a degenerative brain disease characterized by: memory loss, mood swings, cognitive impairment, depression, confusion, aggression and the decline of motor skills. Some studies have suggested that CTE may triple the risk of an early death. 
         [0004]    The risk of concussions and other head trauma is especially prevalent in American Football due to the number of impacts a player&#39;s head may receive. Despite every football player wearing a helmet, football has the highest incidence of concussions of the major sports. This illustrates that there is a need for a helmet that may further reduce the likelihood of a player receiving a concussion. 
         [0005]    In order to understand how helmets may be improved, the different types of forces that can cause head trauma need to be understood. The two major types of forces are acceleration-deceleration (or linear impact) and rotational (or angular impact). 
         [0006]    Briefly a linear impact occurs when a person&#39;s head is struck by a “straight-line” force causing the head to move in the direction opposite of the force. During such an impact the forces may cause the brain to move relative to the skull possibly even causing the brain to strike the inside of the skull. This movement and potential striking of the brain may cause stretching and tearing of neurons or brain cells. 
         [0007]    An angular impact causes the head to experience rotational acceleration and is quite different from a linear impact. In this case, a force causes the head to rotate on its axis (corresponding to the neck) from side to side in a twisting motion. When a player&#39;s head is forced to rotate quickly over a large degree of rotation, nerve cells and blood vessels in the brain can be stretched, twisted and torn. The twisting and tearing of an axon may result in the death of the neuron. Consequently the damage caused by rotational impacts may be particularly severe. 
         [0008]    Helmets are designed to prevent head injuries, including concussions, by absorbing the impact forces to the head. The helmet should absorb and redirect that energy. Existing helmets are able to absorb linear impacts somewhat effectively. However, they are poor at absorbing rotational impacts. As a result of their potential severity, rotational impacts may be the cause of more sport concussions than linear impacts. 
         [0009]    Current helmets protect against linear impacts through the use of an outer polycarbonate surface (hard) and an inner layer of heavy, snug fitting and shock absorbing padding (foam, air cells, etc). The shock absorbing padding fits snuggly around the head, and is usually made of vinyl nitrate or expanded polypropylene. Such helmet designs may be effective at absorbing the force of hard hits to the head and preventing both skull fractures and direct impact concussions by distributing the force across the entire surface area of the helmet. Traditional helmets have the ability to withstand multiple impacts, by compressing and returning to its original dimensions. The outer shell of lightweight yet hard material also disperses kinetic energy. 
         [0010]    However, the shock absorbing padding is designed to fit so closely to the wearer&#39;s head, that if the helmet receives a rotational impact in such a way to rotate the helmet, the head is subject to the same rotational impact and will also rotate on its axis (neck) as a result of the shock absorbing padding. Current football helmets in use today are not effective at providing protection against external forces that cause rotational impacts, which may lead to concussions. The inner padding fits so close to a person&#39;s head that rotational impacts to the helmet also cause rotation of the person&#39;s head. 
         [0011]    Adding to the danger is the fact that the general shape of helmets, especially helmets with facemasks, may actually increase the amount of rotational force placed upon the wearer&#39;s head. This is a consequence of the force hitting the helmet a distance away from the head. The helmet may essentially act as a gear to increase the torque placed on the wearer&#39;s head. 
         [0012]    New shapes of helmets such as the Riddell Revolution™ and the Riddell Revolution 360™ promise reduction technology by introducing a more spherical shape among other improvements. 
         [0013]    The existing designs can still be improved to help reduce rotational impacts on the wearer. A suggested improvement has been the use of a lubricated flexible membrane, which is usually located between the head and the padding. Such helmets have several limitations. First the human head is not spherical and, as such, the lubricated layer may not actually allow the helmet to rotate on the head. Additionally, the rotation of the helmet may block the vision of the person, which may be very dangerous, and players may not want to wear a helmet that may limit their effectiveness in this manner. Finally the lubricated layer will permit the helmet to move around a lot, and would place far too much dependence on the chin strap. 
         [0014]    A helmet is needed that could help minimize the transfer of rotational impacts from the helmet to the wearer&#39;s head, which may reduce the amount of concussion injuries. A helmet is also needed that may be able to reduce the transfer of lateral impacts and rotational impacts, without reducing the wearer&#39;s sightlines and without placing too much emphasis on the chin strap. 
         [0015]    While this invention may be described in relation to football helmets, it is contemplated that it could be adapted for use in any type of helmet. For example it could be used in hockey helmets, motorcycle helmets, baseball helmets, bicycle helmets, ski/snowboard helmets, skateboarding helmets, lacrosse helmets, etc. The invention could be adapted for any headgear worn by a person to reduce the likelihood of head trauma. 
       SUMMARY OF THE INVENTION 
       [0016]    In a broad aspect, then, the present invention provides a helmet comprised of: a stiff outer shell; an inner liner adapted to be fitted to a wearer&#39;s head; a shock absorbing layer located between, and connected to, said stiff outer shell and said fitted inner layer; wherein said shock absorbing layer is adapted to allow said outer shell to flex rotationally relative to said inner layer in order to cushion a rotational force applied to said outer shell, and wherein said shock absorbing layer is adapted to allow said outer shell to move linearly relative to said inner liner in order to cushion a linear force applied to said outer shell. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  illustrates the interior of a complete modified helmet of the present invention; 
           [0018]      FIG. 2  illustrates the interior of a modified helmet of the present invention without an inner layer; 
           [0019]      FIG. 3  illustrates a testing apparatus used to test the present invention; 
           [0020]      FIG. 4  illustrates the testing apparatus with a helmet placed on the mannequin bust. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    With reference to the drawings different embodiments of the present invention will now be described. 
         [0022]    Turning to  FIG. 1 , one embodiment of the present invention is illustrated. A modified football helmet  1  has an outer shell  10  and an inner liner  20 . Outer shell  10  and inner liner  20  may be separated by a shock absorbing layer  30 . Outer shell  10  may be the hard outer layer of a helmet (for example polycarbonate) as would be understood by a person skilled in the art. 
         [0023]    In one embodiment inner shell  20  is custom fit to the wearer&#39;s head. For example, inner shell  20  could be constructed from fiberglass molded to the wearer&#39;s head. However, other materials are contemplated as would be understood by a person skilled in the art. As will be discussed, inner shell  20  may be affixed to shock absorbing layer  30  in a manner that allows inner shell  20  to move both laterally and rotationally relative to outer shell  10 . 
         [0024]      FIG. 2  illustrates one embodiment of shock absorbing layer  30 . In this embodiment shock absorbing layer  30  is a plurality of individual cylindrical pieces of flexible foam padding  32 . Foam padding  32  may be affixed at one end to outer shell  10 . The other end of foam padding  32  may be affixed to inner liner  20  as can be seen best in  FIG. 1 . 
         [0025]    Shock absorbing layer  30  is adapted to act as a flexible buffering system between outer shell  10  and inner liner  20  in two different manners. First, shock absorbing layer  30  may allow outer shell to move laterally relative to inner shell  20 . This lateral movement cushions the wearer&#39;s head from lateral impacts to the helmet. Shock absorbing layer  30  may also disperse lateral impacts throughout shock absorbing layer  30 , thus further reducing the impact felt by the wearer. This type of protection is common among existing helmets. 
         [0026]    Second, and importantly, shock absorbing layer  30  may also allow outer shell  10  to rotate relative to inner shell  20 . This rotational movement may cushion the wearer&#39;s head from rotational impacts to the helmet. In addition to allowing rotational movement, shock absorbing layer  30  may also disperse the rotational force of a rotational impact throughout shock absorbing layer  30 , thus further reducing the rotational impact felt by the wearer. 
         [0027]    Therefore, shock absorbing layer  30  should be able to compress and/or move in multiple directions. Shock absorbing layer  30  should also return to its original shape and position after any movement, thus after an impact (either rotational or lateral) outer shell  10  may return to its original position relative to inner liner  20 . 
         [0028]    A plurality of cylindrical pieces  32  may work well as shock absorbing layer  30  because each individual piece can compress longitudinally and can also flex laterally. Different sized pieces  32  may provide different advantages. While foam pieces have been described herein, it is contemplated that pieces  32  could be constructed from any appropriate material as would be understood by a person skilled in the art. 
         [0029]    While in one embodiment shock absorbing layer  30  has been described as a plurality of cylindrical pieces  32  herein, it would be understood by a person skilled in the art that any type of padding that is capable of compression and/or movement in multiple directions may function to absorb both lateral impacts and rotational impacts. 
         [0030]    The result of shock absorbing layer  30  being able to move/compress both longitudinally and laterally is if the outer layer of the helmet is subject to a rotational impact, the rotational force is not directly translated to the head and neck of the wearer. Shock absorbing layer  30  may have more flex, redirection and absorption capabilities—than the standard current helmet padding. 
         [0031]    Additionally, helmet  1  may actually reduce some lateral impacts more effectively than traditional helmets. For example a ‘glancing’ blow to helmet  1  (for example near the top of the helmet) may result in helmet  1  moving laterally. In a traditional helmet, the full force of a ‘glancing’ lateral impact needs to be absorbed. In contrast, helmet  1  will absorb some of a ‘glancing’ lateral impact by rotating slightly. This is due to shock absorbing layer  30 &#39;s ability to allow inner liner  20  to rotate relative to outer shell  10  and to cushion the force. As a result, when a ‘glancing’ force strikes the top of helmet  1 , outer shell  20  may move both laterally and rotationally and shock absorbing layer  30  may absorb the force both laterally and rotationally. 
         [0032]    While the invention has been described with reference to various embodiments, the scope of the claims should not be limited by the embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole. 
       Testing 
       [0033]    One embodiment of the present invention was tested to see if the effects of rotational impacts on a wearer would be reduced compared to a traditional helmet. For the testing, a Riddell Revolution helmet was used. This helmet had received a 5 star rating by the College of Engineering at Virginia Tech in 2012, which tested a variety of professional football helmets. 
         [0034]      FIG. 3  illustrates the testing apparatus  50  without a helmet. A mannequin bust  60  is affixed to a 25 pound turntable  70 . A swinging weight (5 lb)  52  is suspended above mannequin bust  60 .  FIG. 4  illustrates the same testing apparatus  50  where helmet  1  is placed on mannequin bust  60 . An aluminum bar  62  is affixed to helmet  1 &#39;s facemask  2  so that it extends laterally outward from helmet  1 . 
         [0035]    Swinging weight  52  is positioned so that it is adapted to strike aluminum  62  in order to create a rotational impact on helmet  1 . Swinging weight (5 lb)  52  was released from a horizontal position and the rotation of mannequin bust  60  relative to its starting position was measured. 
         [0036]    First, the testing apparatus was used to test the rotational impacts imparted on the mannequin using the unmodified Riddell Revolution helmet. The unmodified helmet was placed securely on mannequin bust  60 . Aluminum bar  62  was secured to the helmet and weight  52  was dropped from a horizontal position so that it struck aluminum bar  62  and the rotation of mannequin bust  60  was measured 10 times. The average rotation of mannequin bust  60  was 27.55 degrees. The results of each trial are shown below in table 1. 
         [0037]    Second, the testing apparatus was used to test an embodiment of the present invention. The outer shell  10  of the same Riddell Revolution helmet tested as a control was used for consistency. The original inner padding was removed from the helmet and replaced with a numerous cylindrical pieces of foam padding  32  cut to match the thickness of the helmet padding (see  FIG. 1  and  FIG. 2 ). The cylindrical pieces of foam were glued to outer layer  10  such that they extended inwardly. 
         [0038]    A custom fit fiberglass inner liner  20  was form fitted to mannequin bust  60 &#39;s head. The outer side of inner liner  20  was sprayed with an adhesive and affixed to the inwardly extending pieces of foam padding  32  (see  FIG. 1 ). 
         [0039]    The completed modified helmet was placed on mannequin bust  60  with a secure fit. Again, aluminum bar  62  is affixed to helmet  1 &#39;s facemask so that it extended forwardly from the helmet. Swinging weight  52  was dropped from the same horizontal position (same height as the unmodified helmet) to strike piece of wood  62  and the rotation of mannequin bust  60  was measured 10 times. The average rotation for modified helmet  1  of the present invention was 18.2 degrees of rotation. The results of each trial are shown below in table 1. 
         [0000]    
       
         
               
             
               
               
               
             
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Results of Testing 
               
             
          
           
               
                 Trial 
                 Degrees of Angular Rotation 
                 Degrees of Angular Rotation 
               
               
                 Number 
                 (unmodified helmet) 
                 (unmodified helmet) 
               
               
                   
               
             
          
           
               
                 1 
                 27.5 
                 17 
               
               
                 2 
                 28 
                 18 
               
               
                 3 
                 28 
                 18 
               
               
                 4 
                 27 
                 17 
               
               
                 5 
                 27 
                 18 
               
               
                 6 
                 27 
                 19 
               
               
                 7 
                 28 
                 20 
               
               
                 8 
                 28 
                 20 
               
               
                 9 
                 28 
                 18 
               
               
                 10 
                 27 
                 17 
               
               
                   
               
             
          
         
       
     
         [0040]    Thus, the testing showed a reduction of about 9.35 degrees of rotation. This corresponds to 33.8% less rotation transmitted from the rotational impact. 
         [0041]    The results suggest that the present innovative helmet design, having a shock absorbing layer that allows an inner liner to move both laterally and rotationally relative to the outer shell and inner liner, may have significant reduction in head concussions in contact sports such as football, particularly concussions caused by rotational impact forces. 
         [0042]    The inner liner of the present has been described as being custom fit from fiberglass. While this is certainly a workable way of providing a custom fit inner liner that will tend not to rotate on a person&#39;s head, it is expected that in production, the inner liner will be made from a heat moldable plastic material, so that a person could select a helmet with a liner size approximately correct for their head, and then heat the liner with a hair dryer until it is moldable. The helmet would then be put on, and the inner liner would mold itself to the head. Suitable plasters include polycaprolactones and polycaprolactone/polyurethane blends.