Abstract: An air pressure indicator attaches to a manifold and uses air pressure to elide a pressure pin outward. A spring moves the pressure pin inward when pressure decreases in the manifold. A collet and o-ring on the pressure pin prevent the flow of pressurized fluid through the interior of the indicator.

Abstract: An emergency breathing device has a manifold with two threaded receivers for holding compressed air cartridges and two parallel bores. A first bore holds a primary plunger. A collar on the plunger rests on a nylon seal, which is supported on a ledge between the relatively small lower bore and the larger upper bore. A drive spring surrounds an upper portion of the primary plunger and bears against the collar. A housing receives and abuts the spring, and slides an upper part of the plunger through an axial bore in the housing. Detent pins extend through radial bores in the housing. Detent springs urge the detent pins outward. The plunger has a recess which receives semi-spherical inner ends of the detent pins when the plunger is pushed upward against drive spring force. A bell-shaped cap has a bevelled lower edge and a cylindrical inner surface, which presses the detent pins inward against detent spring force.