Safety helmets with cellular textile composite structure as energy absorber

Abstract

This invention provides a safety helmet in the form of a cycling helmet or similar. The helmet has an outer shell and an energy-absorbing liner within the outer shell. The energy-absorbing liner is provided by a cellular textile material combined with a matrix material to form a composite. The composite material retains some porosity from the original textile material to both improve breathing of the liner and also its capability for large deformations to improve energy absorption. The liner may also be provided with a linkage structure to link adjacent cells to improve the absorption of impact loads over a number of adjacent cells in the composite material.

1 . A safety helmet comprising: 
 an outer shell;    an energy-absorbing liner within said outer shell; and    wherein said energy-absorbing liner includes a cellular textile composite material in which at least a portion is a porous textile material supported in a matrix material wherein a plurality of pores are retained in said portion of the composite.    
     
     
         2 . A safety helmet as claimed in  claim 1  wherein said cellular textile composite includes a textile fabric and a matrix material saturating strands of said textile material and retaining pores between strands of said textile material.  
     
     
         3 . A safety helmet as claimed in  claim 2  wherein said textile fabric includes a fabric manufactured from yarns or fibres of high-density polymeric materials.  
     
     
         4 . A safety helmet as claimed in  claim 2  wherein said matrix material comprises a polymer resin.  
     
     
         5 . A safety helmet as claimed in  claim 1  wherein said cellular textile composite provides a plurality of cells in the form of flat-top conical cell structures.  
     
     
         6 . A safety helmet as claimed in  claim 1  wherein a linkage structure is provided to link adjacent cells such that impact energy may be dissapated by a plurality of adjacent cells.  
     
     
         7 . A safety helmet as claimed in  claim 6  wherein an interlocking linkage is provided in the form of a reversibly facing nested textile composite.  
     
     
         8 . A safety helmet as claimed in  claim 6  wherein a linkage is provided in the form of a thin layer of material surrounding and interconnecting individual cells with adjacent cells.  
     
     
         9 . A safety helmet as claimed in  claim 6  wherein a linkage is provided in the form of a foam material surrounding individual cells and interconnecting adjacent cells.  
     
     
         10 . A method of manufacturing a liner for a safety helmet comprising the steps of: 
 providing a sheet of textile fabric;    forming said textile fabric at controlled temperatures to provide a plurality of projecting cells;    forming said fabric with said cells into a generally hemispherical shape for use as a helmet liner;    forming linkages of adjacent cells;    applying resin as a matrix material at one or more stages throughout the method to form a textile fabric composite structure retaining a plurality of pores of the fabric in at least a portion of the resulting composite; and    curing said composite for use as a helmet liner.    
     
     
         11 . A method of manufacturing a helmet liner as claimed in  claim 10  wherein a flat textile fabric sheet is formed into a substantially planar preform with projecting cells prior to formation into a generally hemispherical three-dimensional shape for use as a liner.  
     
     
         12 . A method of manufacturing a liner as claimed in  claim 10  wherein a substantially flat textile fabric is applied directly to a three-dimensional generally hemispherical mold for simultaneous formation into the generally hemispherical shape for a liner and formation of the projecting cells.  
     
     
         13 . A method of manufacturing a liner as claimed in  claim 10  wherein said controlled temperatures comprises controlling the temperature during formation of the cells to a temperature below the melting point of the fibres in the textile fabric but above the glass transition temperature.  
     
     
         14 . A method of manufacturing a liner as claimed in  claim 10  wherein said step of applying resin as a matrix material is performed at more than one stage throughout the method.  
     
     
         15 . An apparatus for the manufacture of a textile composite structure for use in a liner of a safety helmet comprising: 
 at least a first temperature controlled mould having co-operating moulding services to form a plurality of projecting cells into a substantially planar sheet of textile fabric;    a generally hemispherical head-shaped base shell having a plurality of projecting mandrels to receive said textile fabric wherein said mandrels support some or all of said projecting cells; and    means to apply resin at one or more stages throughout the process to form a textile composite structure.    
     
     
         16 . An apparatus for the manufacture of a textile composite structure as claimed in  claim 15  wherein said generally hemispherical head-shaped base shell is provided as an inflatable or compressible base shell that may be collapsed after formation of the textile composite structure for removal.  
     
     
         17 . An apparatus for manufacture of a textile composite structure as claimed in  claim 15  wherein said generally hemispherical head-shaped base shell is provided as a substantially solid hemispherical base shell carrying a plurality of mandrels, at least some of said mandrels being removable to assist in release of the composite structure from said base shell.  
     
     
         18 . An apparatus for the manufacture of a textile composite structure for use as a liner in a safety helmet comprising: 
 at least one temperature controlled mould having two co-operating moulding surfaces having a generally hemispherical head-shaped configuration and carrying a plurality of mandrels to form a textile fabric into a generally hemispherical head-shaped structure and simultaneously form a plurality of projecting cells in said fabric; and    means to apply resin before, during or after said moulding process.    
     
     
         19 . An apparatus for the manufacture of a textile composite structure as claimed in  claim 18  wherein one or both of the co-operating moulds are provided in connectable portions to form the generally hemispherical head-shaped surface such that, upon disconnection, said moulding surface can be removed.  
     
     
         20 . An apparatus for the manufacture of a textile composite structure as claimed in  claim 18  or  19  wherein at least a portion of a surface of one of said moulding surfaces is provided with a biased portion to assist in the release of the composite structure from said moulding surface.