Process for void creation in a helmet

Abstract

This disclosure provides a method for making a helmet comprising a cavity between the outer shell and energy management layers.

1 . A method for preparing a cavity in a helmet, the method comprising:
 forming a rigid sheet having a first surface on a first side of the sheet and a second surface on the opposed side of the sheet and a flange extending away from the first surface wherein the first surface and the flange provide a portion of the boundary of the cavity;   applying a layer comprising a foam composition to the second surface of the rigid sheet to provide a first assembly comprising the rigid sheet and a first foam layer;   disposing the first assembly in an outer shell of a helmet body, wherein the flange contacts the inner surface of the outer shell to define a separation of the inner surface of the outer shell into a first portion and a second portion, and the flange, first surface of the rigid sheet and the first portion of the inner surface of the outer shell form a boundary of a void in a desired shape of the cavity;   applying a second layer of a foam composition to the second portion of the inner surface of the outer shell and the first foam layer of the first assembly to provide a helmet body having a cavity between the outer shell and the first and second foam layers.   
     
     
         2 . The method of  claim 1  wherein the cavity is disposed in a region of the helmet body corresponding to a brow region of a user wearing the helmet. 
     
     
         3 . The method of  claim 1  wherein the rigid sheet is formed in an arcuate configuration wherein the first surface is convex, the second surface is concave and the flange is disposed on an edge of the rigid sheet separating the first surface and the second surface and extends away from the first surface in the convex direction. 
     
     
         4 . The method of  claim 1  further comprising attaching at least one first additional component to the rigid sheet prior to applying the first foam layer. 
     
     
         5 . The method of  claim 4  wherein the at least one first additional component comprises a brow snap. 
     
     
         6 . The method of  claim 5  wherein the first foam layer is applied to a surface of the brow snap proximate to the second surface of the rigid sheet. 
     
     
         7 . The method of  claim 1  further comprising disposing at least one second additional component in the void prior to applying the second foam layer. 
     
     
         8 . The method of  claim 7  wherein the at least one second additional component comprises one or more pivot mechanisms for a visor or eyeshield. 
     
     
         9 . The method of  claim 8  wherein the one or more pivot mechanisms are disposed in the void in a region of the helmet body corresponding to a region of a user wearing the helmet proximate to the temporal regions of the user. 
     
     
         10 . The method of  claim 1  wherein the rigid sheet comprises polycarbonate. 
     
     
         11 . The method of  claim 1  wherein the foam composition of the first foam layer and the foam composition of the second foam layer independently comprise expanded polypropylene (EPP), expanded polystyrene (EPS), expanded polyurethane (EPU), or expanded polyolefin (EPO). 
     
     
         12 . The method of  claim 1  wherein forming the rigid sheet comprises vacuum forming, thermal forming, or a combination thereof. 
     
     
         13 . The method of  claim 1  wherein applying the first foam layer or the second foam layer comprises in-molding. 
     
     
         14 . A helmet comprising a helmet body comprising a cavity, the helmet body comprising
 an outer shell;   an assembly disposed within the outer shell comprising
 a rigid sheet having a first surface on a first side of the sheet and a second surface on the opposed side of the sheet and a flange extending away from the first surface wherein the first surface and the flange provide a portion of the boundary of the cavity; and a layer comprising a foam composition applied to the second surface of the rigid sheet; 
 wherein the flange contacts the inner surface of the outer shell to define a separation of the inner surface of the outer shell into a first portion and a second portion, and the flange, first surface of the rigid sheet and the first portion of the inner surface of the outer shell form a boundary of a void in a desired shape of the cavity; and 
 a second layer of a foam composition applied to the second portion of the inner surface of the outer shell and the first foam layer of the assembly to provide a helmet body having a cavity between the outer shell and the first and second foam layers. 
   
     
     
         15 . The helmet of  claim 14  wherein the cavity is disposed in a region of the helmet body corresponding to a brow region of a user wearing the helmet. 
     
     
         16 . The helmet of  claim 14  wherein the rigid sheet is formed in an arcuate configuration wherein the first surface is convex, the second surface is concave and the flange is disposed on an edge of the rigid sheet separating the first surface and the second surface and extends away from the first surface in the convex direction. 
     
     
         17 . The helmet of  claim 14  further comprising at least one first additional component attached to the rigid sheet of the assembly. 
     
     
         18 . The helmet of  claim 17  wherein the at least one first additional component comprises a brow snap. 
     
     
         19 . The helmet of  claim 18  wherein the first foam layer is applied to a surface of the brow snap proximate to the second surface of the rigid sheet. 
     
     
         20 . The helmet of  claim 14  further comprising at least one second additional component disposed in the cavity. 
     
     
         21 . The helmet of  claim 20  wherein the at least one second additional component comprises pivot mechanisms for a visor or eyeshield. 
     
     
         22 . The helmet of  claim 21  wherein the pivot mechanisms are disposed in the cavity in a region of the helmet body corresponding to a region of a user wearing the helmet proximate to the temporal regions of the user. 
     
     
         23 . The helmet of  claim 14  wherein the rigid sheet comprises polycarbonate. 
     
     
         24 . The helmet of  claim 14  wherein the foam composition of the first foam layer and the foam composition of the second foam layer independently comprise expanded polypropylene (EPP), expanded polystyrene (EPS), expanded polyurethane (EPU), or expanded polyolefin (EPO).