Patent ID: 6837245

Claim:
For use in a system including a user-donnable breathing device for supplying breathing oxygen to a user of the device, the improvement comprising: a control valve for selectively switching from a normal source of the breathing oxygen to a pressurized emergency source of breathing oxygen associated with the device, the control valve including: a valve body having a normal source inlet, an emergency source inlet, and a delivery outlet for delivery of the breathing oxygen to the user of the device when donned; the valve including a poppet configured when in a normal position for permitting oxygen from the normal source to flow into the valve body and then out through the delivery outlet; a normal oxygen supply fitting associated with the normal source inlet; a releasable retention device for maintaining the poppet in its normal position; a cocked piston normally occupying a cocked position and shiftable when released from its cocked position for being urged against the supply fitting, a drive device biasing the piston in its cocked position for urging the piston against the poppet to maintain the cocked position, the poppet normally preventing the piston from being driven from the cocked position by the drive device, a seal for normally preventing flow of oxygen from the emergency source until ruptured; a rupturer interposed between the piston and the seal to rupture the seal by being driven by the piston when released from its cocked position; the retention device being selectively releasable by the user, the retention device when released permitting the poppet to move, in response to urging of the piston, from the normal poppet position to a flow blocking poppet position, so as to block the normal source inlet and to allow the piston to be driven against the rupturer; the seal when ruptured permitting the emergency breathing oxygen to flow through the valve body and then through the delivery outlet for user emergency breathing.