Three-layer helmet assembly with breathing gas throttle

Claim 1

A helmet comprising: a body adapted to enclose the head of a wearer, said body including a bypass formed in said body, said bypass having an entrance means for allowing breathable gas to flow into said bypass, said body further including an ambient air access port formed therein; a casing adapted to enclose the head of a wearer positioned inside of said body, said casing comprising a breathable gas reservoir and an outlet port; a mask secured to said body defining an enclosed space and adapted to cover the nose and mouth of a wearer, said mask including an inlet pipe connected to said outlet port of said breathable gas reservoir and supplying breathable gas into said mask, said mask including a partition means for separating said mask into a first space for receiving exhaled gas, and a second space communicating with said inlet pipe for receiving breathable gas from said breathable gas reservoir; a tube connecting said ambient air access port of said body to said mask; a filter means disposed in said ambient air access port for filtering air flowing through said ambient air access port into said mask; throttle means disposed in said inlet pipe for controlling the flow of breathable gas; and an outlet means communicating with said first space for discharging exhaled gas, said outlet means connected to said entrance means for drawing exhaled gas outward through said outlet means responsive to breathable gas flowing through said bypass to said mask.