Patent attributes
A protective helmet includes a head cap, which surrounds and moves with a wearer's head, and an outer shell which surrounds the head cap. The outer shell is movable both radially and circumferentially relative to the head cap. An energy absorbing flexible liner is located between the head cap and the outer shell. The liner is attached to the outer shell and the head cap so that neither the head cap nor the head of the wearer is otherwise attached to the outer shell. The liner establishes a preset initial relative position and spacing between the head cap and the outer shell and compliantly absorbs energy imparted to the outer shell during a helmet impact to enable the outer shell to move relative to the head cap during the helmet impact and to be returned to the initial relative position with the head cap following the impact.