US Patent 8667618 Helmet

A helmet (1, 100, 200) for protecting a user's head (90), comprising a cap (2) for protecting the user's cranium (92) and a chin guard (3) for protecting the user's chin (93), wherein the chin guard (3) is adapted to move between a first protecting position (31) and a second protecting position (32) under the action of a force (50) acting in the direction of the chin (93) of a user wearing on said helmet (1), the chin guard (3) in said second protecting position (32) being nearer to the user's chin (93) with respect to the chin guard (3) in said first protecting position (31).