US Patent 11330858 Helmet

Plural contact pieces of a shaft member, which is mounted to a helmet main body, abut a cam surface that is formed at a hole portion provided in a proximal end portion of a chin guard. When the chin guard is rotated from a fully closed position to a fully open position with respect to the helmet main body, at least one of the contact pieces abuts an anchor surface, and, simultaneously, at least another one contact piece fits into a concave portion, and, due thereto, the chin guard is fixed with respect to the helmet main body.