Hard Hat with Impact Performance Materials

Abstract

A hard hat, including an outer shell constructed of material designed to provide protection to a wearer in extreme environmental conditions is provided. In one embodiment, the wall thickness of the outer shell is reduced to minimize the weight and/or bulk of the hard hat.

What is claimed is: 
     
         1 . A hard hat, comprising:
 an outer shell, the outer shell comprising:
 an exterior surface; 
 an interior surface defining a cavity sized to receive a head of an operator; 
 a brim portion defining a lower circumference extending along the exterior surface; 
 an impact protection layer positioned within the cavity; 
   wherein the outer shell is formed from a material that includes a yield strain greater than 9%.   
     
     
         2 . The hard hat of  claim 1 , wherein the outer shell material includes a yield strain between 13% and 15%. 
     
     
         3 . The hard hat of  claim 1 , wherein the outer shell material includes a strain to failure greater than 17%. 
     
     
         4 . The hard hat of  claim 3 , wherein the outer shell material includes a strain to failure between 70% and 80%. 
     
     
         5 . The hard hat of  claim 1 , wherein the outer shell material includes a notched izod impact strength greater than 450 joules/meter. 
     
     
         6 . The hard hat of  claim 5 , wherein the notched izod impact strength of the outer shell material is between 700 and 750 joules/meter. 
     
     
         7 . The hard hat of  claim 1 , wherein the outer shell material includes a tensile strength between 50 MPa and 60 MPa. 
     
     
         8 . The hard hat of  claim 1 , wherein the outer shell material is a polymer material. 
     
     
         9 . A hard hat, comprising:
 a shell formed from a rigid material, the shell comprising:   an exterior surface;   an interior surface defining a cavity configured to receive a head of an operator;   a crown portion positioned in a central area of the hard hat surrounding a center point;   a bottom portion defining a lower circumference extending along the exterior surface;   wherein the shell material includes a tensile strength of greater than 35 MPa.   
     
     
         10 . The hard hat of  claim 9 , wherein the shell material includes a tensile strength between 50 MPa and 60 MPa. 
     
     
         11 . The hard hat of  claim 9 , wherein the shell material includes a yield strain greater than 9%. 
     
     
         12 . The hard hat of  claim 9 , wherein the shell material is a rigid polymer material. 
     
     
         13 . The hard hat of  claim 9 , wherein the shell material includes a strain to failure greater than 17%. 
     
     
         14 . The hard hat of  claim 9 , wherein the shell material includes a notched izod impact strength greater than 160 joules/meter. 
     
     
         15 . The hard hat of  claim 14 , wherein the shell material includes a notched izod impact strength between 650 and 680 joules/meter. 
     
     
         16 . The hard hat of  claim 9 , wherein the outer shell material includes a multi-axial impact toughness greater than 27 joules. 
     
     
         17 . A hard hat, comprising:
 an outer shell formed from a rigid material, the outer shell comprising:
 an exterior surface; 
 an interior surface defining a cavity configured to receive a head of an operator; 
 a crown portion positioned in a central area of the hard hat surrounding a center point; 
 a bottom portion defining a lower circumference extending along the exterior surface; 
 an impact protection layer positioned within the cavity; 
   wherein the outer shell material includes a multi-axial impact toughness greater than 27 joules.   
     
     
         18 . The hard hat of  claim 17 , wherein the multi-axial impact toughness of the outer shell material is between 65 and 75 joules. 
     
     
         19 . The hard hat of  claim 17 , wherein the outer shell material includes a tensile strength greater than 9% and a tensile strength greater than 35 MPa. 
     
     
         20 . The hard hat of  claim 17 , wherein the outer shell material includes a strain to failure greater than 17%.