A curved visor mechanism for helmets with laterally moveable visors that move on guides that define a track attached to the helmet. The visors are curved in the shape of a sector of an annulus of a circle. Using such a shape allows the track defined by the visors to maintain a nonzero rake angle at the...http://www.google.co.uk/patents/US5953760?utm_source=gb-gplus-sharePatent US5953760 - Curved visor mechanism for helmets with laterally moveable visors
