Collapsible helmet

A collapsible helmet comprising:

• (a) a left arched member and a right arched member, each of said left and right arched members having a front portion and a rear portion, said front portions of said left and right arched members being hingedly attached at a front attachment point and said rear portions of said left and right arched members being hingedly attached at a rear attachment point, thereby forming a substantially elliptic headcover, said headcover surrounding the left and the right head hemispheres of a wearer when the helmet is deployed in its operative position;
• (b) a middle arched member, said middle arched member having a front portion and a rear portion, said front portion of said middle arched member being hingedly attached at said front attachment point to said left and right arched members, said rear portion of said middle arched member being hingedly attached at said rear attachment point to said left and right arched members, said middle arched member extending longitudinally across the crown of a wearer when the helmet is deployed in its said operative position so as to define a head protecting shell;
• and
• (c) at least one flexible strap connecting said middle arched member with said left and right arched members, said at least one flexible strap being stretched when the helmet being deployed in said operative position,
• wherein said middle, said left and said right arched members assume a folded inoperative position in which they overlap form a compact, layered, arch-shaped package, with said at least one flexible strap folded amongst any of said arched members.