Patent Publication Number: US-RE43173-E

Title: Helmet with in-mold and post-applied hard shell

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of provisional U.S. Application No. 60/527,452, filed on Dec. 5, 2003, incorporated herein expressly by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention is related to a helmet having an outer shell, wherein the shell is constructed from an in-mold shell portion and a post-applied shell portion, and to the method of making the helmet. 
     BACKGROUND OF THE INVENTION 
     Conventional helmets typically include a hard exterior shell and a foam liner interior to the shell. There are two widely-used methods of making a helmet with a liner and shell. In one method, the hard outer shell and the foam liner are both made independently of each other. Thereafter, the shell is applied to the liner with glue, rivets, screws or is otherwise attached by physical means. As used throughout this application, “post-applied shell” refers to a shell or shell portion attached to the foam liner, after the foam liner has been pulled from the mold, and such technique is referred to as the “post-applied method.” In a second method, the helmet&#39;s hard outer shell is bonded to the helmet&#39;s inner foam liner simultaneously with the formation of the liner. The liner is cast with the shell in the mold. The liner material, typically polystyrene, is injected into the mold containing the hard outer shell. As used throughout this application, “in-mold shell” refers to a shell or shell portion that is bonded to the foam liner at the time of formation of the foam liner, and such technique is referred to as the “in-mold method.” The advantage with the latter method is that the in-mold method results in a sturdier attachment between the shell and the liner that can prevent separation of the shell from the liner under a severe impact. The former method, however, is not without advantages. 
     While the in-mold method has a distinct advantage in strength, the post-applied method also has an advantage that cannot be fully realized in a helmet with an in-mold shell. For example, independently forming the liner and the shell, and thereafter, attaching the shell to the liner, after formation of the liner, permits the creation of channels on the exterior surface of the liner (i.e., the surface facing the shell). Thus, when the shell and liner are brought together, the channels on the liner are converted into conduits between the shell and liner that are useful for providing ventilation. Air flow between the shell and the liner is not possible with a helmet having an in-mold shell, since all the interior surfaces of an in-mold shell are covered with the foam liner as a result of the method used. 
     Accordingly, there is a need to provide a sturdy in-mold shell helmet with the ventilation advantages of a post-applied shell helmet. Alternatively, there is a need for a sturdy shell to liner attachment in a post-applied shell helmet. The present invention fulfills these needs and has further related advantages. 
     SUMMARY OF THE INVENTION 
     The present invention is related to a helmet having an interior foam liner and at least two shell portions exterior to the liner. The helmet includes an exterior in-mold shell portion covering a portion of the liner. The helmet also includes an exterior post-applied shell portion covering a portion of the liner that is not covered by the in-mold shell portion. In one embodiment, the in-mold shell portion comprises polycarbonate and the post-applied shell portion comprises poly(acrylonitrile-butyl-styrene). The helmet includes conduits located between the liner and the exterior post-applied shell portion for ventilation and air flow for removing the heat generated by a user. The liner is made with channels and through-bores that form the various air entry and exit points and the conduits of the helmet. The exterior post-applied shell portion includes holes and vent fins to assist in the entry, exit, and direction of the air flow through the conduits. 
     A method of making a helmet having a liner and a shell includes placing a first shell portion in a mold and making a casting of a foam liner to provide a liner with an in-mold shell portion bonded to the liner and partially covering a portion of the liner that is desired to have a sturdy attachment between the in-mold shell and the liner. After removing the liner from the mold, the method includes attaching a second shell portion to the liner portions that are not covered by the in-mold shell portion. Because the liner has been provided with channels and through-bores, the application of the post-applied shell portion results in conduits and entry and exit points for the air that are created from the post-applied shell portion and the liner. 
     The helmet made in accordance with the invention provides numerous advantages, including the ability to provide ventilation between the shell and the liner where ventilation is important, but also provides a structurally stout attachment between the shell and the liner where the integrity of the shell and liner attachment is important or alternatively, where ventilation is unimportant. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is an illustration of a helmet according to the present invention; 
         FIG. 2  is an illustration of a foam liner casting partially covered by an in-mold shell portion bonded to the liner; 
         FIG. 3  is an illustration of a shell portion for post applying to the liner; 
         FIG. 4  is an illustration showing the joining of a foam liner with an in-mold shell portion to a post-applied shell portion; and 
         FIG. 5  is an illustration of the venting capabilities of a helmet having an in-mold shell portion and a post-applied shell portion. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Generally, helmets include an interior shock absorbent liner made from a material capable of being foamed, such as polystyrene, polyurethane, or other similar materials, and an exterior hard shell made from materials, such as polycarbonate and poly(acrylonitrile butadiene-styrene) (ABS). 
     A first conventional method of producing a liner with a shell includes casting the foam liner with the entire shell in the mold. After curing, the foam liner is pulled from the mold with the in-mold shell integrally bonded to the foam liner. Additionally, other helmet components besides the entire shell can be cast with the foam liner to integrally embed the helmet components in the liner. In the in-mold method, all interior surfaces of the shell are exposed to the foam and are, therefore, bonded to the foam liner. The in-mold method leaves no spaces between the interior surface of the shell and the foam liner, thereby providing a very sturdy attachment that can withstand a severe impact. However, the advantage of the in-mold method also results in a helmet that cannot be provided with venting between the shell and the liner for the very reason that all interior surfaces of the shell are fully covered by the foam. Venting between the shell and the liner is desirable in some instances for increasing the rate of heat removal from the body. 
     A second conventional method of producing a liner with a shell includes manufacturing the liner and the entire shell independently of one another and then bonding or otherwise attaching the entire shell to the liner with an adhesive or through the use of rivets, screws or other hardware. The liner is typically made by injecting or pouring polystyrene granules inside of a mold and allowing the polystyrene to expand to the shape of the mold. A mold release can be applied to the mold surface, prior to casting the liner for separating the liner from the mold. The positive mold can be provided with any number of ridges and protrusions, which result in channels and through-bores in the negative foam liner casting that is removed from the mold. Once the foam liner is removed from the mold, the shell can be bonded to the foam liner. 
     In the post-applied method, it is not necessary that the shell have the exact contours of the foam liner. If venting is desired between the shell and liner, it is advantageous that the shell does not have the exact contours so that conduits can be formed between the shell and the liner out of the channels in the liner to allow for airflow therein. In direct contrast to the post-applied method for making a helmet, the in-mold method of making a helmet is not suitable for creating spaces for air flow between the shell and the liner. This is because the in-mold method exposes all the interior surfaces of the shell to the foam liner. While it is possible to put apertures that extend through both the shell and the liner in an in-mold helmet, it is not possible to provide channels for airflow between the shell and the liner. In some instances, apertures that extend through both the shell and the liner are insufficient to remove the heat generated by a user. 
     According to the present invention, a helmet with a liner is provided that has at least one in-mold shell portion and at least one post-applied shell portion. The advantages of each shell type can be exploited by locating the post-applied shell portion or portions where ventilation between the shell and liner is desired, for example, at the coronal or frontal areas of the helmet. The coronal area is desirable because heat rises, and the frontal area is desirable because air impacts the front of the helmet. The in-mold shell portion or portions can be applied to the remainder of the liner not covered by the post-applied shell or where ventilation is of relatively minor importance. Alternatively, the in-mold shell portion or portions can be applied to the areas where a sturdy attachment between shell and liner is desired to protect the most sensitive areas of the head. In one embodiment of the invention, for example, an in-mold shell portion can be applied at the occipital area of the helmet because air does not impact the helmet in the occipital area as compared with the frontal or coronal area. It is also possible to have overlapping portions at the boundaries of the in-mold and post-applied shell portions. One or more in-mold shell portion or portions and one or more post-applied shell portion or portions can be applied to the helmet. In other embodiments, it is possible that the in-mold shell portion can be applied at other locations besides the occipital area. For example, the in-mold shell portion can be applied to the temporal, frontal or coronal areas of the helmet. Besides a monolithic in-mold shell portion, more than one in-mold shell portion can be applied to any one or more portions of the liner. Similarly, the post-applied shell portion can be a monolithic shell portion, or alternatively, post-applied shell portions can be applied at distinct areas of the liner. Generally, terms such as occipital (back), coronal (top), temporal (side) and frontal (front) denote areas of the skull, as used herein however, the terms are used to denote areas on the liner, shell or helmet that are in proximity to these corresponding areas of the skull. It is to be appreciated when referring to locations that designations such as occipital, temporal, coronal, and frontal give only approximate locations. Also, directions, such as upper, lower, bottom or side, are to be taken in the context of the application figures and are not limiting. 
     Referring now to  FIG. 1 , a helmet  100  according to the present invention, is illustrated, wherein the helmet  100  may include an in-mold shell portion  102  at the occipital area of the helmet  100 , and a post-applied shell portion  104  at the coronal area of the helmet. The post-applied shell portion  104  may also extend to the frontal and temporal areas of the helmet  100 . In-mold shell portion  102  may extend into the temporal areas as well. Protective eyewear  106  is shown with the helmet  100  and the eyewear  106  is attached by band  108  to a post  110  on the side of the helmet  100  at the temporal area. Goggles, suitable as eyewear  106  is described in U.S. patent application Ser. No. 11/003,929, filed on Dec. 3, 2004, titled “Banded Goggles for a Winter Sports Helmet.” This application is expressly incorporated herein by reference. While the eyewear  106  and helmet  100  can be made to be used as a set, it is not necessary that the helmet  100  be made specifically for use with eyewear  106 . The helmet  100  can be made with or without the post  110 . The helmet  100  may include accessory helmet components, such as ear muffs  192 , plastic trim  190 , interior padding  191 , such as textile covered foam and textile mesh, front and rear vents  193 ,  195 , chin strap  197 , and chin strap buckle  199 . 
     Referring now to  FIG. 2 , an illustration of the in-mold shell portion  102  and liner  112  as viewed looking down on the exterior coronal area of the liner  112 , is provided. It is to be appreciated that liner  112  is contoured in a shape suitable to be worn on the head. The in-mold shell portion  102  is shown bonded to the liner  112  at the top of the illustration. The in-mold shell portion  102  may be applied generally in the occipital and lower temporal areas, however, other areas of liner  112  may be covered by the in-mold shell portion  102 . The in-mold portion  102  has been applied in a modification of the conventional in-mold method that only uses a partial shell. 
     The areas of the liner  112  not covered by the in-mold shell portion  102  are exposed foam and may be provided with a variety of features, including channels and through-bores. The in-mold method results in the absence of voids between the inner, major surface of the in-mold shell portion  102  and the outer, major surface of the liner  112 . Accordingly, where ventilation between the shell and liner is desired, no in-mold shell portion has been provided. As seen in  FIG. 2 , the liner  112  includes channels  114 ,  116 ,  118 ,  120 ,  122 ,  124 ,  126 , and  128  which may extend parallel to the major surface of the liner  112  from the frontal area to the upper occipital area. These channels may later form conduits for air when the post-applied shell portion is bonded to the liner  112  at a subsequent step. The liner  112  also includes through-bores that completely penetrate through the liner  112  thickness perpendicular to the major surface of the liner  112 . Through-bores  130  and  132  are representative of the through-bores on both the right and left halves of the helmet  100 . Through-bores are provided within the channels for a reason which is described below. Through-bores may also be provided outside the channels. The post-applied shell  104  of  FIG. 1  can selectively cover some or all of the through-bores to provide ventilation through the post-applied shell  104  and liner  112  and also between the post-applied shell  104  and liner  112 . Generally, through-bores not within a channel are provided for ventilation exclusively through the shell and liner, while through-bores in the channels are provided for ventilation through and between the shell and liner. The liner  112  may further includes ridges  134 ,  136 ,  138 ,  140 ,  142 , and  144  between the channels. It is apparent that by applying the post-applied shell  104  that has a smooth interior major surface, conduits may be created from the channels in the liner  112  and the shell  104  that may extend from the frontal area to the occipital area of the helmet  100 . It can be appreciated that some or all of the through-bores within the channels may be covered with the shell, thereby providing a mechanism for the transfer of heat from the head to the channels, so that the removal of heat can be effectuated by air flow within the channels. A center ridge  145  may be provided with elongated through-bores  146 ,  148 . Through-bores  146 ,  148  do not lie in channels and therefore may be provided for ventilation through the thickness of the helmet  100 . Liner  112  also may include recessed areas  150 ,  152 , at the frontal area of the liner  112 . The recessed area  150  leads into recessed channels  114 ,  116 ,  118 , and  120 ; and the recessed area  152  leads into recessed channels  122 ,  124 ,  126 , and  128 . Recessed areas  150  and  152  provide a space to install opening and closing vent lids, of which vent lid  193  shown in  FIG. 1 , is representative. Channels may also terminate at the occipital area as recesses or depressions, so that vent fins can fit within the channels. 
     Referring now to  FIG. 3 , an illustration of the interior, major surface of the post-applied shell  104  that may be attached to the liner  112 , is provided. It can be seen by comparison with  FIG. 2  that the post-applied shell  104  does not have the exact contours that are provided in the liner  112 . The post-applied shell  104  may be smooth in the areas, such as coronal areas  154 ,  156 , where the shell  104  provides cover for the channels shown in  FIG. 2 . Post-applied shell  104  may also includes holes, such as holes  158 ,  160 , at the frontal area of the shell  104 , and pluralities of holes, such as holes  162 ,  164 , at the coronal area of the shell  104 . Frontal holes  158  and  160  are provided for fresh air entry, while holes, which are represented by holes  162 ,  164  are for heat exit. Pluralities of vent fins, such as vent fins  166 ,  168 , are interposed between the holes at the coronal area, and are at an angle. The post-applied shell  104  includes pluralities of vent fins at the occipital area, of which vent fins  172 ,  174 , are representative. Vent fins  172 ,  174 , may project downward to lie in between the channels in the liner  112  shown in  FIG. 2 . Vent fins  172  are shown included in vents  195  in  FIG. 1 . 
     The post-applied shell  104  may define the entry points and exit points for air when the shell  104  is applied to the liner  112 . Holes  158 ,  160  may be provided for air entry due to their placement at the frontal area where air impact is at its greatest, while vent fins  172  and  174  may lie at the air flow exit at the occipital area, when combined with liner  112  and in-mold shell portion  102 . The post-applied shell  104  may provide cover for the areas that are not covered by the in-mold shell portion  102 , excepting some overlap at the boundary region between the in-mold shell portion  102  and the post-applied shell portion  104  that creates an overhang  170  at the occipital area of the helmet  100  as seen in  FIG. 1 . 
     Referring now to  FIG. 4 , an illustration showing the post-applied shell portion  104  being applied to the liner  112  with the in-mold shell portion  102 , is provided. As seen in the illustration, the post-applied shell portion  104  may be constructed so that when applied to the liner  112 , various features of the post-applied shell portion  104  cooperate with the features of the liner  112  to produce conduits for ventilation. For example, the smooth interior surfaces  154 ,  156  may come to rest adjacent and parallel to the raised ridges, of which  140 ,  142 , and  144 , are representative. Channels  122 ,  124 ,  126 , and  128  are therefore covered by the smooth surface  156  to provide conduits for air flow between the liner  112  and post-applied shell  104 . As can be seen in the illustration, through-bores, such as through-bore  130 , may contribute to ventilation by allowing the passage of air and heat from the head into channels, such as channel  128 . The air flow in the conduit formed from channel  128 , for example, exits at the occipital area between the vent fins  172 . Similar construction may be found on the opposite half of the helmet. Vent lids  176 ,  178  are shown adjacent to hole  158  and hole  160  that is covered by the vent lid  176  and therefore hole  160  is not shown. The vent lids  176  and  178  may fit within recesses  150  and  152  formed in the liner  112 . Vent fins  172  and  174  located at the occipital area of the post-applied shell  104  are shown extending perpendicular to the interior, major surface of the post-applied shell  104 . Vent fins  172 , for example, are designed to fit within the channels  122 ,  124 ,  126 , and  128 , as shown in  FIG. 2 . Through-bores  146  and  148  at the coronal area of the liner  112  may be partially covered by the vent fins  166  and  168  located at the coronal area of the post-applied shell  104 . It can be appreciated that heat and air rising through the through-bores  146  and  148  may escape from between the vent fins  166  and  168 . It can also be appreciated that heat rising from the through-bore  130  may be carried away by the air entering from the hole  158 , which then passes into the recess  152  and therefrom is distributed to the various channels, of which channel  128  is representative, and may exit at the occipital area of the helmet between the vent fins  172 . 
     Referring now to  FIG. 5 , an illustration diagramming various possible air flow paths through the post-applied shell portion  104  and the liner  112 , is provided. Air and heat is diagrammed being carried away from the coronal area of the helmet  100  through hole  162  between coronal vent fins, such as vent fin  166 , shown in  FIG. 4 . Such air and heat may pass through through-bore  148  of liner  112  shown in  FIG. 4 . The heat may be carried away by the air flowing over the exterior surface of the helmet  100 . Outside air may enter through frontal holes  160  and  158  of the post-applied shell  104 , shown in  FIG. 3 , in between the fins of vent lids  176  and  178  located at the frontal area of the helmet  100 , shown in  FIG. 4 . Vent lids  176  and  178  can be moved up or down to permit or close off air flow. The air may then enter the recessed portions  150 ,  152  shown in the liner  112  in  FIG. 4 . The air may then enter one of the plurality of conduits formed from the channels of the liner  112  shown in  FIG. 2 . It can be appreciated that heated air rising through the through-bores at the channels, such as through-bore  130 , can be carried away by the air flowing within the conduits formed from the channels. Heat and air exits the channels between the liner  112  and the post-applied shell  104  at the occipital area of the helmet  100  through vents on each side of the helmet  100 , such as vent  195 , as seen in  FIG. 1 . Accordingly, a helmet with an in-mold shell portion and a post-applied shell portion may have the advantage of a very stout shell to liner bond, with the added advantage of ventilation between the shell and the liner. Furthermore, in the method of making a helmet in accordance with the invention, an in-mold shell portion is provided in a mold, from which the liner is formed. The mold may be provided with any number of features to create channels and through-bores in the liner. After removal from the mold, the liner is glued to a post-applied shell otherwise attached to create air passages for ventilation between the liner and the post-applied shell. Furthermore, it can be appreciated that any of the exterior shell may be provided with detailing designed to provide an aerodynamic advantage and appeal to users. 
     While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.