Abstract: A helmet with an optical display system is provided with a custom fit protective liner which precisely aligns the wearer's eyes with the optics on the helmet. The helmet is manufactured by positioning the subject's head in a fixture; determining the position of the subject's pupils with respect to the fixture; scanning the subject's head with a laser while positioned in the fixture in order to obtain a 3-D model of the subject's head; and providing a helmet liner having an outer surface which is profiled to position it inside a helmet shell. The position of the subject's pupils may be determined by scanning pupil locating features of the fixture. The 3-D model is then used to provide the helmet liner with an inner surface which conforms to the subject's head and is positioned with respect to the outer surface so that the outer surface will have a predetermined position with respect to the subject's pupils. The helmet liner is then fitted in the helmet shell to form a helmet.

Abstract: A helmet with an optical display system is provided with a custom fit protective liner which precisely aligns the wearer's eyes with the optics on the helmet. The helmet is manufactured by positioning the subject's head in a fixture; determining the position of the subject's pupils with respect to the fixture; scanning the subject's head with a laser while positioned in the fixture in order to obtain a 3-D model of the subject's head; and providing a helmet liner having an outer surface which is profiled to position it inside a helmet shell. The position of the subject's pupils may be determined by scanning pupil locating features of the fixture. The 3-D model is then used to provide the helmet liner with an inner surface which conforms to the subject's head and is positioned with respect to the outer surface so that the outer surface will have a predetermined position with respect to the subject's pupils. The helmet liner is then fitted in the helmet shell to form a helmet.

Abstract: An airflow system for use with a helmet includes a face piece adapted to enclose the eyes of the wearer to form a first cavity and to enclose the nose and mouth of the wearer to form a second cavity isolated from the first cavity. Filtered air normally flows through an inlet to the first cavity, from which it flows to the second cavity through a conduit and eventually to the ambient region through an exhalation duct leading from the second cavity. The air is supplied under pressure to the first cavity and the exhalation duct provided with check valves at its inlet and outlet to maintain a positive pressure in the first cavity, thereby to prevent the infiltration of noxious gases, over most of the breathing range. A spring-loaded check valve normally admits additional air directly to the second cavity through a second inlet to prevent excessive airflow through the first cavity across the eyes of the wearer.