Protective helmets having energy absorbing liners

Abstract

In one embodiment, a protective helmet includes an outer shell and an inner liner provided within the outer shell, the liner comprising an energy absorber including a first layer, an opposed second layer, and a plurality of energy absorbing columns provided between the layers, wherein the columns include relatively long columns that are attached to both the first and second layers and relatively short columns that are attached to only one of the first and second layers.

1 . A protective helmet comprising:
 an outer shell; and   an inner liner provided within the outer shell, the liner comprising an energy absorber including a first layer, an opposed second layer, and a plurality of energy absorbing columns provided between the layers, wherein the columns include relatively long columns that are attached to both the first and second layers and relatively short columns that are attached to only one of the first and second layers.   
     
     
         2 . The helmet of  claim 1 , wherein the energy absorber is made of a thermoplastic elastomer. 
     
     
         3 . The helmet of  claim 2 , wherein the energy absorber is made of thermoplastic polyurethane. 
     
     
         4 . The helmet of  claim 1 , wherein the energy absorbing columns are cylindrical. 
     
     
         5 . The helmet of  claim 1 , wherein there are three or more different lengths of energy absorbing columns in the energy absorber so as to provide three or more different stages of energy absorption. 
     
     
         6 . The helmet of  claim 1 , wherein the relatively long columns are approximately 18 to 65 millimeters long and approximately 3 to 7 millimeters in cross-sectional dimension. 
     
     
         7 . The helmet of  claim 1 , wherein the relatively short columns are approximately 8 to 55 millimeters long and approximately 2 to 6 millimeters in cross-sectional dimension. 
     
     
         8 . The helmet of  claim 1 , wherein the energy absorbing columns form acute angles no greater than approximately 15 degrees with the normal directions of the layers. 
     
     
         9 . The helmet of  claim 1 , wherein the energy absorbing columns and at least one of the first and second layers have a textured surface that reduces slippage. 
     
     
         10 . The helmet of  claim 1 , wherein the energy absorbing columns are kinked. 
     
     
         11 . The helmet of  claim 1 , wherein the energy absorber includes a supplemental energy absorbing member positioned between the first and second layers and in a space formed between the energy absorbing columns. 
     
     
         12 . The helmet of  claim 1 , wherein the inner liner further comprises an cushion adapted to contact a wearer's head. 
     
     
         13 . An inner liner for use inside an outer shell of a protective helmet, the inner liner comprising:
 an energy absorber including a first layer, an opposed second layer, and a plurality of energy absorbing columns provided between the layers, wherein the columns include relatively long columns that are attached to both the first and second layers and relatively short columns that are attached to only one of the first and second layers.   
     
     
         14 . The liner of  claim 13 , wherein the energy absorber is made of thermoplastic polyurethane. 
     
     
         15 . The liner of  claim 13 , wherein the energy absorbing columns are cylindrical. 
     
     
         16 . The liner of  claim 13 , wherein there are three or more different lengths of energy absorbing columns in the energy absorber so as to provide three or more different stages of energy absorption. 
     
     
         17 . The liner of  claim 13 , wherein the relatively long columns are approximately 18 to 65 millimeters long and approximately 3 to 7 millimeters in cross-sectional dimension. 
     
     
         18 . The liner of  claim 13 , wherein the relatively short columns are approximately 8 to 55 millimeters long and approximately 2 to 6 millimeters in cross-sectional dimension. 
     
     
         19 . The liner of  claim 13 , wherein the energy absorbing columns form acute angles no greater than approximately 15 degrees with the normal directions of the layers. 
     
     
         20 . The liner of  claim 13 , wherein the energy absorbing columns and at least one of the first and second layers have a textured surface that reduces slippage. 
     
     
         21 . The liner of  claim 13 , wherein the energy absorbing columns are kinked. 
     
     
         22 . The liner of  claim 13 , wherein the energy absorber includes a supplemental energy absorbing member positioned between the first and second layers and in a space formed between the energy absorbing columns. 
     
     
         23 . The liner of  claim 13 , wherein the inner liner further comprises an cushion adapted to contact a wearer's head.