Abstract: The invention pertains to protective helmet that has an inflatable liner that is constructed with a multiplicity of cells each separated by constrictions of a narrower cross-section. The liner has a central ring and a plurality of loops extending therefrom adapted to protect various portions of the wearer's skull. The structure of the liner permits the liner to be molded using various molding techniques.

Abstract: A fit system positionable adjacent interior portions of a helmet and cranial surfaces of a cranium of a wearer of the helmet proximate the interior portions of the helmet for improving the fit of the helmet to the cranium. The system includes an elongate fluid impervious bladder having a first end including an inlet port in fluid communication with the bladder and a second end remote from the first end. The bladder defines a single continuous fluid flowpath between the first end and the second end for receiving fluid introducible into the bladder through the inlet port for expanding the bladder so that substantially the entire length of the bladder may be expanded to engage mutually facing portions of the cranium of the user and interior portions of the helmet.

Abstract: A protective helmet incorporates an inflatable liner that has front, crown, rear, left and right side portions. To ensure uniform inflation, the inflatable liner is comprised of a plurality of inflatable cells interconnected by a series of air passageways. The liner has a front portion that extends to the lower edge of the helmet and a rear portion that extends below the external occipital protuberance of the wearer's head, thereby providing a snug, comfortable fit and ensuring that the helmet will not rise up or lift away from the wearer's head.