US Patent 7870618 Adjustment mechanism for a helmet

A helmet having a helmet shell including cooperating first and second sections in slidable engagement with one another, at least one locking assembly inter-connecting the first and second sections, the locking assembly including a pivoting member pivotable between a locked position and an unlocked position, the pivoting member in the locked position pressing the shell sections against one another such as to prevent a relative sliding motion therebetween, the pivoting member in the unlocked position allowing the relative sliding motion, and at least one engagement member connected to the first shell section and removably engaging the pivoting member in the locked position to prevent accidental movement of the pivoting member toward the unlocked position.