Extension lead for a respirator alarm system

In a respirator having:

• a primary circuit energized by an electrical power source to drive the respirator components;
• a normally closed alarm-initiator circuit connecting with the primary circuit;
• means associated with the respirator components to open the alarm-initiator circuit whenever a respirator component fails or the power source fails;
• a normally open alarm circuit having an alarm means and an independent power source to actuate the alarm means whenever the circuit closes;
• and means associated with the alarm-initiator circuit to close the alarm circuit whenever the alarm-initiator circuit opens, the improvement comprising:
• a disconnectable extension lead extended from the respirator, having a normally-closed, manually-actuatable switch at its extended end adapted to provide a manually actuated alarm function by the patient opening the normally closed manually-actuatable switch, and means in the alarm-initiator circuit adapted to close the circuit at the respirator connection point of the extension lead when disconnection of the extension lead is made, to maintain the alarm-initiator circuit in a closed state, and to open the circuit at the point of connection when connection of the extension lead is made, to place the lead in series with the alarm-initiator circuit.