Crash helmet with retractable elements

Claim 1

Crash helmet of the type comprising a plurality of arcuated elements (17), said elements (17) being articulated to one another at the ends so as to be shiftable between two extreme positions, i.e. between a first operative spread position in which said elements are mutually set apart so as to give rise to a cap structure and a second non-operative retracted position in which said elements are collected and overlapped together, so that the helmet dimensions are substantially the same as those of a single element, means being also provided for mutual articulation and mutual engagement of said elements (17) when in the spread position, said latter position being therefore steadily held, characterized in that said articulation means comprise a plurality of eccentric members (18), one for each element, said eccentric members being integrally fixed to an operating stud (19) which is provided on its end facing the inner part of the helmet with a tightening disc (20) and on its other end is provided with a knob (21) pivoted on said stud (19), said knob (21) having a shaped portion for cooperating with a cam (23) fixed on said stud (19) to draw closer all the spread elements and to engage stably said means for mutual engagement.