Patent ID: 8261374

Claim:
A protective helmet, comprising: a crown made from plastic material; a semi-rigid neckband having two opposite adjustable ends; and adjustment means having a pair of sliding mechanical links joined to said ends of the neckband, each of the sliding mechanical links comprising position indexing means controlled from a slide which is able to be moved from outside in a slit of the crown, the sliding mechanical links being positioned symmetrically on opposite lateral sides of the crown, wherein a length of the neckband remains constant during adjustment, the indexing means being molded directly along with the crown, said position indexing means are securely attached to an inside wall on each lateral side of the crown, and are formed by a rack having two series of notches separated by said slit, and an unlocking button of said slide has a coupling part bearing pins cooperating by clipping with the rack by action of a return spring that is a compression type spring that is arranged between a centering pin securely attached to a securing prong associated with each end of said neckband, and a hole arranged in the coupling part.