Custom fitted helmet and method of making the same

Abstract

A helmet that is custom-fitted to a wearer's head, and methods of making the helmet, are provided A method includes the steps of positioning a shape-forming means over the wearer's head, and hardening the shape-forming means to provide a hardened headform that substantially conforms to the shape of the wearer's head. The shape-forming means can be a stretchable beanie cap that is coated or impregnated with a curable polymeric material, a heat-softenable plastic sheet, or a strip or plurality of strips of curable tape that are wrapped about the wearer's head to provide a headwrap. Once the hardened headform has been made, it can be used to cast a hardened plaster fixture for use as the “male” member in a mold for casting an energy absorbing foam liner for a helmet which has an inner surface substantially conforming to the shape of the wearer's head. Alternatively, the hardened headform can itself be used as the “male” member of the liner casting mold. In a further alternative, the hardened headform can be digitized to produce computer-readable data from which a suitable machine, such as a CNC router, can machine a pre-made energy absorbing liner “blank” so as to provide an inner surface thereof having a complementary contour to the wearer's head.

1 . A method of making an energy absorbing liner that is custom-fitted to a wearer's head comprising 
 a) positioning a shape-forming means over said wearer's head, and hardening said shape-forming means to provide a hardened headform that substantially conforms to the shape of said wearer's head;    b) generating computer-readable data comprising a surface map of the hardened headform;    c) providing a pre-made energy absorbing liner blank having at least one surface; and    d) machining said at least one surface of said energy absorbing liner blank, based on said computer-readable data, to provide a convex surface therein whose shape and contour substantially conform to the shape and contour of said hardened headform.    
   
   
       2 . A method according to  claim 1 , said impact energy absorbing liner blank comprising viscoelastic flexible foam.  
   
   
       3 . A method according to  claim 1 , said impact energy absorbing liner blank comprising expanded polystyrene.  
   
   
       4 . A method according to  claim 1 , said impact energy absorbing liner blank comprising expanded polypropylene.  
   
   
       5 . A method according to  claim 1 , further comprising providing a barrier over said wearer's head prior to positioning said shape-forming means thereover.  
   
   
       6 . A method according to  claim 1 , said energy absorbing liner blank being made by molding a foaming composition in a mold, and curing said foaming composition to provide said energy absorbing liner blank, said liner blank thereby being a foam liner blank.  
   
   
       7 . A method according to  claim 6 , said energy absorbing foam liner blank comprising viscoelastic flexible foam.  
   
   
       8 . A method according to  claim 6 , said energy absorbing foam liner blank comprising expanded polystyrene.  
   
   
       9 . A method according to  claim 6 , said energy absorbing foam liner blank comprising expanded polypropylene.  
   
   
       10 . A method according to  claim 6 , said foaming composition comprising isocyanate and at least one polyol.  
   
   
       11 . A method according to  claim 1 , said shape-forming means being a heat-softenable plastic sheet that is heated and positioned over said wearer's head in a heat-softened state, and is maintained in place over said wearer's head until said heat-softened plastic sheet hardens to yield said hardened headform substantially conforming to the shape of said wearer's head.  
   
   
       12 . A method according to  claim 11 , said heat-softened plastic sheet being provided in the form of a crude flower having at least 3 elements.  
   
   
       13 . A method according to  claim 12 , at least one of said elements having a laterally extending tab, the laterally extending tab being pressed against an adjacent one of said elements of the plastic sheet to aid in defining the shape thereof to conform to the wearer's head.  
   
   
       14 . A method according to  claim 1 , said shape-forming means being a stretchable beanie cap that is coated or impregnated with a curable polymeric material and is positioned and maintained snugly over said wearer's head until the curable polymeric material cures to yield said hardened headform substantially conforming to the shape of said wearer's head.  
   
   
       15 . A method according to  claim 14 , said curable polymeric material being in the form of a curable liquid resin.  
   
   
       16 . A method according to  claim 14 , said curable polymeric material being water curable.  
   
   
       17 . A method according to  claim 14 , said beanie cap being a knitted polyester fabric that is impregnated with a water curable polyurethane resin.  
   
   
       18 . A method according to  claim 1 , said shape-forming means being at least one strip of curable tape that is wrapped about said wearer's head to provide a headwrap made from said curable tape that substantially conforms to the shape of said wearer's head, said headwrap being cured to yield said hardened headform substantially conforming to the shape of said wearer's head.  
   
   
       19 . A method according to  claim 18 , said shape-forming means being a plurality of strips of said curable tape.  
   
   
       20 . A method according to  claim 18 , said curable tape being made from a textile material that has been coated or impregnated with a curable polymeric material.  
   
   
       21 . A method according to  claim 18 , said curable tape being made from a curable polymeric material.  
   
   
       22 . A method according to  claim 18 , said curable tape being water curable.  
   
   
       23 . A method according to  claim 20 , said curable polymeric material being water curable.  
   
   
       24 . A method according to  claim 18 , said curable tape being made from a fiberglass fabric that has been coated or impregnated with a curable polymeric material.  
   
   
       25 . A method according to  claim 24 , said curable polymeric material being water curable.  
   
   
       26 . A method according to  claim 1 , further comprising providing said impact energy absorbing liner in a motorcycle helmet.  
   
   
       27 . A method according to  claim 1 , further comprising manipulating said computer-readable data to increase the effective radius along at least a portion of the surface map of the hardened headform in order to provide a predetermined clearance to accommodate the installation of comfort fitting foam into a helmet adjacent finished energy absorbing liner made from said liner blank.  
   
   
       28 . A method according to  claim 1 , said energy absorbing liner blank being machined using CNC machinery, based on said computer-readable data, to provide a finished energy absorbing liner having said convex surface therein whose shape and contour substantially conform to the shape and contour of said hardened headform.  
   
   
       29 . A method according to  claim 28 , said CNC machinery comprising a CNC router.  
   
   
       30 . A method according to  claim 1 , said computer-readable data being stored in a computer-readable data file.  
   
   
       31 . A method according to  claim 1 , said computer-readable data being generated by scanning said hardened headform using a digitizer or a coordinate measuring machine capable of scanning the headform to measure the surface dimensions and contour thereof.  
   
   
       32 . A method according to  claim 31 , said digitizer or coordinate measuring machine using lasers to scan the surface dimensions and contour of the hardened headform.  
   
   
       33 . A helmet that is custom fitted to a particular wearer's head, the helmet comprising an impact energy absorbing liner made according to the method of  claim 1 .  
   
   
       34 . A helmet according to  claim 33 , said energy absorbing liner comprising viscoelastic flexible foam.  
   
   
       35 . A helmet according to  claim 33 , said energy absorbing liner comprising semi-rigid viscoelastic flexible foam.  
   
   
       36 . A helmet according to  claim 33 , said energy absorbing liner comprising expanded polystyrene.  
   
   
       37 . A helmet according to  claim 33 , said energy absorbing liner comprising expanded polypropylene.  
   
   
       38 . A helmet according to  claim 35 , said foam exhibiting substantially 100% crush recovery following an impact.  
   
   
       39 . A helmet according to  claim 35 , said foam being effective to attenuate the force bf impact resulting from an impact velocity anywhere in the range of 2-7 m/sec, and to dissipate a substantial portion of said impact force away from a localized region of impact.