Apparatus for controlling or assisting respiration

Claim 1

IN APPARATUS FOR CONTROLLING OR ASSISTING RESPIRATION OF THE TYPE HEREINBEFORE SPECIFIED, A COMBINED PRESSURE CONTROL FOR INTERCONNECTION BETWEEN A SOURCE OF PRESSURIZING GAS AND MEANS FOR DELIVERING GAS UNDER PRESSURE TO THE LUNGS OF A PATIENT, SAID CONTROL INCLUDING PRESSURE RESPONSIVE TIMING MEANS COMPRISING A VARIABLE CAPACITY GAS CHAMBER HAVING ONE WALL FORMED AS A PRESSURE RESPONSIVE MEMBER, CONTROL VALVE MEANS IN SAID CONTROL MOVABLE BETWEEN OPEN AND CLOSED POSITIONS, SAID VALVE MAGNETICALLY COUPLED TO SAID PRESSURE RESPONSIVE MEMBER TO MOVE SAID CONTROL VALVE BETWEEN OPEN AND CLOSED POSITIONS IN RESPONSE TO PRESSURE VARIATIONS TO CONTROL THE FLOW OF PRESSURIZING GAS THROUGH SAID CONTROL, INLET MEANS IN SAID CONTROL INTERCONNECTING SAID PATIENT AND SAID VARIABLE CAPACITY GAS CHAMBER FOR ADMITTING FLUID AT A PRESSURE CLOSELY RELATED TO SAID PATIENT''S LUNG PRESSURE TO THE INTERIOR OF THE VARIABLE CAPACITY GAS CHAMBER DURING THE INHALATION PHASE OF THE RESPIRATORY CYCLE, SAID PRESSURE RESPONSIVE MEMBER MOVABLE IN RESPONSE TO A PREDETERMINED PRESSURE IN THE LUNGS TO MOVE SAID VALVE TO THE CLOSED POSITION, OUTLET MEANS FOR RELEASING GAS AT A CONTROLLED RATE FROM THE CHAMBER DURING THE EXHALATION PHASE OF THE RESPIRATORY CYCLE WHEREBY THE PRESSURE RESPONSIVE MEMBER IS MOVED TO OPEN SAID CONTROL VALVE MEANS, AND ADJUSTABLE LOADING MEANS OPPOSING MOVEMENT OF SAID PRESSURE RESPONSIVE MEMBER TO CLOSE SAID CONTROL VALVE MEANS COMPRISING A FIRST BIASING MEANS CONNECTED TO SAID PRESSURE RESPONSIVE MEMBER OPERATIVE TO BIAS SAID MEMBER IN ONE DIRECTION OVER THE WHOLE RANGE OF MOVEMENT OF SAID PRESSURE RESPONSIVE MEMBER, AND SAID SECOND BIASING MEANS EFFECTIVE TO OPPOSE SELECTED STAGES OF SAID MOVEMENT.