Helmet with slip plane system

Abstract

A helmet may have an inner liner forming a body of the helmet, the inner liner having a concave inner surface defining a cavity configured for receiving a wearer's head. A plurality of slippage pads are disposed at selected locations on the concave inner surface and connected to the inner liner, the slippage pads having an elongated shape with a length and a width, the length being greater than the width, the slippage pads each defining a number of integrally connected side-by-side tubes each having an opening adapted to be oriented toward the wearer's head, the openings aligned longitudinally along the length of the slippage pads. A plurality of projecting cushioning pads are disposed adjacent to the slippage pads, and have a greater height than the slippage pads and exhibiting a greater deformability than the slippage pads.

1 . A helmet comprising:
 at least an inner liner forming a body of the helmet, the inner liner having a concave inner surface defining a cavity configured for receiving a wearer's head;   a plurality of slippage pads disposed at selected locations on the concave inner surface and connected to the inner liner, the slippage pads having an elongated shape with a length and a width, the length being greater than the width, the slippage pads each defining a number of integrally connected side-by-side tubes each having an opening adapted to be oriented toward the wearer's head, the openings aligned longitudinally along the length of the slippage pads;   a plurality of projecting cushioning pads disposed adjacent to the slippage pads, and having a greater height than the slippage pads and exhibiting a greater deformability than the slippage pads; and   an attachment system to attach the helmet to the wearer's head.   
     
     
         2 . The helmet as defined in  claim 1 , wherein all the slippage pads are shaped and size to be identical to each other. 
     
     
         3 . The helmet as defined in  claim 1 , wherein lateral pairs of the slippage pads are disposed on each side of a sagittal plane of the helmet. 
     
     
         4 . The helmet as defined in  claim 3 , wherein the lateral pairs of the slippage pads are evenly laterally spaced apart from the sagittal plane of the helmet. 
     
     
         5 . The helmet as defined in  claim 1 , wherein a frontal pair of the slippage pads is disposed in a frontal portion of the helmet. 
     
     
         6 . The helmet as defined in  claim 1 , further comprising at least one cushioning pad disposed on the concave inner surface of the inner liner. 
     
     
         7 . The helmet as defined in  claim 6 , wherein the cushioning pad has apertures defined therethrough, the apertures corresponding in shape and dimensions to the slippage pads, wherein some of the slippage pads and/or of the plurality of projecting cushioning pads are disposed within the apertures of the cushioning pad. 
     
     
         8 . The helmet as defined in  claim 1 , wherein the slippage pads have a length of 40 mm±20 mm, and a width of 13 mm±7 mm. 
     
     
         9 . The helmet as defined in  claim 1 , wherein the projecting cushioning pads have a largest sectional dimension of 12.5 mm±2.5 mm. 
     
     
         10 . The helmet as defined in  claim 1 , wherein the projecting cushioning pads have a height of 7.0 mm±2.0 mm. 
     
     
         11 . The helmet as defined in  claim 10 , wherein the slippage pads have a height of 5.0 mm±2.0 mm. 
     
     
         13 . The helmet as defined in  claim 1 , wherein a density of the slippage pads is 0.27 g/cm 3 ±0.10 g/cm 3 . 
     
     
         14 . The helmet as defined in  claim 1 , wherein the slippage pads are made of a composite material including polyurethane and a non-Newtonian polymeric material. 
     
     
         15 . The helmet as defined in  claim 1 , wherein the plurality of tubes is a pair of tubes, the openings of the pair of tubes each having an obround shape. 
     
     
         16 . The helmet according to  claim 1 , wherein the projecting cushioning pads have a height that is between 5% and 40% greater than that of the slippage pads. 
     
     
         17 . The helmet according to  claim 1 , wherein the projecting cushioning pads are cylindrical tubes. 
     
     
         18 . The helmet according to  claim 1 , wherein the projecting cushioning pads have a hardness ranging from Duro 12-18 HC. 
     
     
         19 . The helmet according to  claim 1 , wherein the slippage pad have a hardness ranging from Duro 25-35 HC. 
     
     
         20 . The helmet according to  claim 1 , wherein a thickness ratio of the projecting cushioning pad relative to the slippage pads is between 1.2 and 1.7, inclusively.