Abstract:
A helmet includes an outer shell and an inner liner. The inner liner includes a visual indicator to indicate when the helmet has experienced an impact of sufficient force to permanently deform a portion of the inner liner. The visual indicator thus indicates when the helmet no longer offers it&#39;s peak level of protection to the wearer and should be repaired or replaced.

Description:
This is a continuation of application No. 09/179,319, filed Oct. 27, 1998 now U.S. Pat. No. 6,065,158. 
     This application claims the benefit of Provisional Application No. 60/063,459, filed Oct. 29, 1997. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to helmets of the type used in athletic contests where the participants typically wear the helmets for protection. The present invention provides for a liner having an impact absorption capability, but which also includes an impact indicator so that a supervisor or the user will be able to determine by inspection of the liner after an impact the character of the impact in terms of its magnitude as well as the location of the impact should it result in injury to the head of the wearer. 
     BACKGROUND OF THE INVENTION 
     In many athletic contests, rough and sometimes dangerous encounters occur particularly among school children such as in football, soccer, and other sports and these have frequently led to injury to the head or spinal column of the user which can result in life long disability and even death. As a consequence, there has been a need for improvements in athletic helmets and a number have become available such as is disclosed in my prior U.S. Pat. Nos. 5,390,367, 5,621,922, 5,539,935, 5,546,609, 5,287,562, and Ser. No. 08/685,840. While these improvements have provided supervisory personnel the ability to monitor unnecessary or dangerous activities during athletic contests or even to prevent injury, the installation of such equipment as well as devices provided by others have not been widely accepted due primarily to the expense and the reluctance of officials to seek funding in already reduced school budgets. 
     The need for improved safety in such contests has become paramount with the increasingly large damage awards to victims, who are often students, who have suffered injury during athletic contests supervised by school officials. In professional sports, it is well known that a number of prime athletes have had their careers shortened or their playing time diminished as a result of head injuries which are not accommodated by the present athletic helmet design. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes a number of the foregoing shortcomings by providing a relatively inexpensive yet superior safety device in the form of a removable liner for a conventional helmet thus avoiding a major expense in redesigning a piece of equipment that is in widespread use. In a preferred embodiment, the invention provides a compressible liner which will have a required low degree of compressibility or resistance to crushing to provide enhanced safety for the wearer of the liner in a conventional athletic helmet such as a football helmet. In addition, the liner is sufficiently flexible and formable to be easily installed from a supply in any size helmet. Further, the material is preferably expanded polystyrene foam where the foam has been expanded with a nontoxic, colored gas. With this arrangement, when an impact on the head of the wearer is experienced, the gas filled cells will burst and leave a color indicator about the site of the impact. A supervisor will then be able to determine whether unnecessary roughness has been employed in the contest or the event and thus be able to take remedial action and additional training for the individual involved. In another embodiment, a multi-layer lining system is employed to assure safety and compression of one or more of the layers only upon receiving an impact above a selected threshold. When so deformed, the affected layer or layers can be removed and easily replaced. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates in sectional view a conventional helmet in which has been installed a liner of the present invention; 
     FIG. 2 illustrates in section a further multi-layer form of the invention; 
     FIG. 3 illustrates in sectional view an alternative embodiment of the invention; and 
     FIG. 4 illustrates in plan view the alternative embodiment of FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings, there is shown schematically in FIG. 1 a sectional view of a conventional football helmet  10  which is typically made of polycarbonate material having the required density and resistance to bending conventionally used in these types of helmets. The helmet has an outer shell  11  having a front portion  12  and a depending rear portion  14  extending down from the crown  16 . In the usual helmet, the side portions such as is illustrated at  18  will cover the ears of the wearer. 
     According to the present invention, a liner of compressible gas expanded foam material such as polystyrene  20  is inserted to cover substantially all of the interior surface  22  of the shell  11 . The liner  20  may be held in place by localized adhesive bonded sites such as at  24  and  26 . In some applications, Velcro-type attachments may be used. The liner  20  should have sufficient resistance to compression to prevent the interior surface  22  of the helmet being contacted by the head of the wearer in the event of most impacts. Also, the polystyrene should be foamed with a non-toxic colored gas so that when a localized compression takes place, the cells of the foam will burst and leave a colored marker to indicate the general area of the site of the impact. 
     Such impacts will be useful to a supervisor or medical personnel in the event the wearer is unconscious after a blow to the head. Frequently, in athletic sports such as football, a participant will use his head as a ram and this can be a source of severe medical injury. In such an event, usually the crown area will be contacted and the liner compressed in that area and inspection of the liner will immediately reveal this to the physician. 
     In FIG. 2 there is shown a further version of the invention where a multi-layer liner including layers  22 ,  30  and  32  are provided superimposed on one another in the shell  11 . Layer  22  will comprise the same material as described above in connection with FIG.  1 . Layer  30  or  32  may usefully comprise a highly absorbent layer of compressible material such as polyurethane foam cushion which after an impact will slowly return to its undeformed condition. The other of the two layers,  30  or  32  may comprise gas filled cells. The density of this layer relative to the layer  22  may be varied to accommodate the nature of the play to be engaged in. 
     In use, the usual impacts of a sport will only cause small, local deformations of the outer layer,  30  or  32  without causing rupture of layer  22 . However, in the event of a severe impact that causes collapse of all layers and rupture of the cells of layer  22 , the liner can be removed and replaced for continued use. 
     Alternatively, the positioning of layers  22  with respect to layers  30  and  32  may be reversed with layer  22  position to the interior of the helmet. 
     In an alternative embodiment as shown in FIG. 3, an inner liner  40  is provided in an outer shell  11 . The inner liner  40  includes a first layer  42  constructed of a material, such as polystyrene, that permanently deforms upon encountering an impact of sufficient force. A thin surface indicator layer  44  is applied to the interior surface of the liner  42 . This indicator layer provides a readily ascertainable visual indication when the helmet has been subjected to an impact of a predetermined sufficient force such as to permanently deform the first layer  42 . The layer  44  can be in the form of a relatively hard, brittle material that will exhibit cracking if the underlying liner layer  42  is deformed sufficiently. As shown in FIG. 4, (with layer  46 , discussed below, removed), the surface of layer  44  can be seen to exhibit cracking  50  in an area subjected to a high impact. The force upon which cracking of the layer  44  occurs can be varied by varying the thickness of the layer and the type of the layer material. 
     Alternatively, the layer  44  can be in the form of a layer of applied microcells containing a dye or colorant that will exhibit a visual color change when the microcells are ruptured upon sufficient impact level and the dye or colorant is exposed to oxygen. Such types of dye-containing microcell coatings are commonly utilized in “carbonless” multi-page forms. For instance, the coating is applied to the backs of the pages, and the force of writing on the top page bursts the microcells underneath, thereby depositing the dye on the page below which then exhibits color upon exposure to oxygen. 
     An additional liner layer  46  is positioned over the layers  42  and  44  and is constructed of an elastically compressible material that will generally return to its shape after impact and not exhibit substantial permanent deformation. Such a material would include polyurethane foam. This layer  46  will absorb the force from normal impacts while the layer  42  does not deform until impacts above a predetermined level are reached. Thus, this layer  46  helps protect the indicator layer  44  and prevent triggering of the visible indicator effect until the impact rises above the predetermined level. This layer, because of its elastic compressibility, also improves the conformability of the helmet to the wearer&#39;s head, thereby improving comfort to the wearer. Additional elastically compressible layers can be placed over the layer  46  and have different densities and compressibility factors to tailor the overall impact/compressibility characteristics of the helmet. Additional permanently deformable layers may be used between the layer  42  and shell  11  with different densities and compressibility factors for the same effect. 
     Alternatively, the indicator layer  44  can comprise one or more rigid housings containing one or more dye or colorant containing cavities that will rupture upon sufficient impact, leaving the visible color indicator. 
     With respect to all of the embodiments disclosed herein, the liners can be segmented so that only the damaged segment need be replaced. Furthermore, each of the embodiments disclosed herein can utilize a surface layer over the compressible layers of Goretex, or other similar material, to repel water from the compressible layers but allow dissipation of accumulated moisture. 
     It should be noted that the liner of this invention can readily be employed with a full face guard type helmet as is disclosed in my earlier U.S. Pat. No. 5,287,562 the disclosure of which is incorporated herein by reference. 
     While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that it is capable of further modifications and is not to be limited to the disclosed embodiment, and this application is intended to cover any variations, uses, equivalent arrangements or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as may be applied to the essential features hereinbefore set forth and followed in the spirit and scope of the appended claims.