Positive pressure breathing apparatus

Claim 1

POSITIVE PRESSURE BREATHING APPARATUS COMPRISING A FLOW CONTROL VALVE HAVING AN INLET AND AN OUTLET SEPARATED BY A VALVE PORT, A VALVE MEMBER NORMALLY CLOSING SAID PORT, MEANS FOR CONNECTING SAID INLET TO A SOURCE OF OXYGEN UNDER PRESSURE, A CHAMBER CONNECTED WITH SAID OUTLET AND PROVIDED WITH AN OUTLET, A CHECK VALVE NORMALLY CLOSING SAID CHAMBER OUTLET, MOUTHPIECE, A BREATHING TUBE CONNECTING SAID CHAMBER OUTLET WITH THE MOUTHPIECE, ACTUATING MEANS IN SAID FLOW CONTROL VALVE RESPONSIVE TO A PREDETERMINED REDUCED FLUID PRESSURE IN THE BREATHING TUBE FOR OPENING SAID PORT, A PRESSURE CONTROL VALVE HAVING AN INLET CONNECTED WITH SAID CHAMBER AND HAVING AN OUTLET TO THE ATMOSPHERE, THE PRESSURE CONTROL VALVE HAVING A CONTROL PORT COMMUNICATING WITH ITS INLET AND OUTLET, VALVE MEANS IN SAID PRESSURE CONTROL VALVE NORMALLY CLOSING ITS OUTLET, SAID BREATHING TUBE BEING PROVIDED WITH AN EXHALATION PORT, A FLUID PRESSURE OPERATED EXHALATION VALVE FOR THE EXHALATION PORT, A CONDUIT CONNECTING SAID CONTROL PORT WITH THE EXHALATION VALVE TO MAINTAIN THE EXHALATION PORT CLOSED WHILE SAID PRESSURE CONTROL VALVE OUTLET IS CLOSED, SHIFTING MEANS ASSOCIATED WITH SAID PRESSURE CONTROL VALVE RESPONSIVE TO A PREDETERMINED INCREASED FLUID PRESSURE IN THE BREATHING TUBE FOR MOVING SAID VALVE MEANS TO OPEN THE PRESSURE CONTROL VALVE OUTLET, AND MANUALLY ADJUSTABLE MEANS FOR VARYING THE RESISTANCE OF SAID SHIFTING MEANS TO MOVEMENT BY SAID INCREASED FLUID PRESSURE.