Abstract: A respirator especially constructed for flight crews has a harness strap which can be inflated to a somewhat rigid, self-sustaining orientation to permit one-handed placement of the respirator over the wearer's head. Once the respirator is in place, release of a lever for inflating the strap deflates the latter to a orientation sufficient to cause the resilient strap to tightly press a peripheral seal of the respirator mask against nose and mouth areas of the user's face. A comfort adjustment to relieve strap tension permits selective reinflation of the strap to a somewhat smaller value than necessary for initial donning of the harness, and the limited reinflation pressure is sufficient for causing the mask to seal against the face during pressure demand breathing. In instances where pressurized breathing is needed, however, pressure within the strap is automatically released so that the strap presents sufficient bias to hold the mask against the face without oxygen leakage therepast.

Abstract: A respirator especially constructed for flight crews has a harness strap which can be inflated to a somewhat rigid, self-sustaining orientation to permit one-handed placement of the respirator over the wearer's head. Once the respirator is in place, release of a lever for inflating the strap deflates the latter to an orientation sufficient to cause the resilient strap to tightly press a peripheral seal of the respirator mask against nose and mouth areas of the user's face. A comfort adjustment to relieve strap tension permits selective reinflation of the strap to a somewhat smaller value than necessary for initial donning of the harness, and the limited reinflation pressure is sufficient for causing the mask to seal against the face during pressure demand breathing. In instances where pressurized breathing is needed, however, pressure within the strap is automatically released so that the strap presents sufficient bias to hold the mask against the face without oxygen leakage therepast.

Abstract: In a system for opening and closing a main line valve by use of high pressure hydraulic fluid which is controlled from a remote location and in which the fluid passes through a hand pump located at the site of the valve, a protective lock-out system is provided for guarding against personal injury in the event the high pressure fluid should arrive at the hand pump while it is being manually operated. The lock-out system includes a small piston located in an air passageway which is positioned outwardly of the hand pump main piston chamber. This passageway extends from the top of the hand pump main piston chamber toward the IN port which receives the high pressure hydraulic fluid. The piston is connected by a shaft to a poppet valve. The high pressure fluid is applied to the under-surface of the piston and to the seat side of the poppet valve.