Protective helmet

摘要

The outer shell (1) is lined with shock-dampening inner material bearing against the wearer's head. The shell contains a large number of openings (5) sealed by cushion material (7 - 10) which protrudes to the outside. The dimensions of the openings can be such as to cause additional elastic distortion of the shell under a force acting against the top. They can be situated in a ring running round the helmet periphery, and in a horizontal plane parallel to the helmet edge. They can be rectangular, typically 2 to 4cm high and 3 to 7cm long, the length always being greater than the height.