Lung controlled pressure gas respirator for use with an oxygen mask and valving mechanism therefor

A valving mechanism for a lung controlled pressure regulator system using a breathing head mask which has an outer mask portion adapted to be substantially sealed around the periphery of a wearer's face and an inner mask portion arranged within the outer mask portion and substantially sealed around the wearer's nose and mouth leaving a pressure space on the interior of said mask between said outer and inner mask portions, comprising:

• a housing, a flexible diaphragm extending across an interior of said housing, said housing having one side located on one side of said diaphragm exposed to atmosphere and having an opposite side on an opposite side of said diaphragm including means adapted to be connected to the mask so as to communicate with the pressure space, said housing having a control valve portion communicating with said opposite side and defining a guide cylinder, a respirator breathing air supply conduit connected to said control valve portion of said housing and communicating with said guide cylinder, a valve member movable in the guide cylinder of said control valve portion, means in said guide cylinder defining two spaced valve seats disposed in a connection between the respirator breathing air supply conduit and said control valve portion of said housing, each of said valve seats being engageable by said valve member for regulating the flow of air through said control valve portion to the pressure space, a control lever pivotally mounted between said diaphragm and said valve member and having an arm portion engaged with said diaphragm and an arm portion engaged with said valve member, and being displaceable by movement of said diaphragm to displace said valve member, said valve member having a first and a second end position for engaging said two valve seats respectively to block a flow of air through said control valve portion and an intermediate position for passing a flow of air through said valve portion to the pressure space, first biasing means connected to said diaphragm and second biasing means connected to said valve member, said first and second biasing means selected to exert forces on said diaphragm and valve member respectively so that, with the pressure space exposed to atmosphere, said diaphragm moves into and end position thereof and said valve member moves into said first end position thereof to block a flow of air through said control valve portion, said first and second biasing means also selected so that with the mask sealed around the periphery of a wearer's face, and with exhalation of the wearer, an excess pressure builds in the pressure space and moves said diaphragm away from its end position to move said valve member into its intermediate position to pass a flow of air through said control valve portion.