Abstract: An assembly for connecting together fluid-conducting spigot and socket members employs a U-shaped locking clip with parallel legs sliding in chordwise passages of the socket member. The spigot member has an external groove which is engaged by the legs of the locking clip intruding into the socket when the spigot is inserted into the socket and the clip is slid into its operational position. The clip can be retained in this position by the "snap" engagement of the base portion of the U-shape with a transverse groove in the face of the socket member. The assembly is particularly useful for connecting a demand valve into the facemask of a breathing apparatus.

Abstract: A breathing apparatus comprises a cylinder assembly supported by a harness through a mounting bracket. The bracket has a leg with an open-ended slot into which a grooved portion of the cylinder assembly is passed. The assembly is secured by screwing a pressure-reducing valve onto the shut-off valve of the cylinder assembly, in so doing a knurled ring on the pressure-reducing valve coming into position adjacent to an edge of the bracket to prevent subsequent withdrawal of the cylinder assembly from the slot.

Abstract: A tilt valve incorporated in a demand regulator for breathing apparatus has a head which seats over an opening through which the valve stem extends for operation by a pressure-responsive diaphragm. This opening defines the outlet port of a chamber wherein the valve head is disposed, the inlet port of the chamber opening to the same side of the valve head as the outlet port. Gas flowing from the inlet port to the outlet port therefore need not pass between the periphery of the valve head and the surrounding wall of the chamber, so that the head can be a close fit in the chamber to ensure a consistent seating of the head over the valved port.

Abstract: A valve, notably for use as a demand valve in breathing apparatus, has a pressure-responsive diaphragm coupled to a separate control member which lies in the path of a jet of gas which vents from a control chamber through an orifice, gas being continuously supplied to the control chamber. Deflection of the diaphragm in response to pressure changes in a second chamber caused by inhalation and exhalation of the user of the apparatus pivots the control member towards or away from the jet orifice to control the rate of venting from the control chamber and thereby vary the pressure within the control chamber. Flow of gas through the valve to the user of the apparatus is controlled by a flexible disc which in turn responds to the pressure in the control chamber. By employing a separate diaphragm and control member the former can be optimized for pressure-response while the latter can be optimized for valve-regulation by interaction with the gas jet from the control chamber.

Abstract: A back-carrying harness assembly, e.g. for supporting a gas cylinder for breathing apparatus on the back of the user, comprises a carrier for the cylinder or other load which is hinged in the region of the user's shoulder blades to a back plate. The back plate extends down the back of the user and is hinged at the lumbar region to the frame of a pelvic girdle. The combined effect of the upper and lower hinging with the location of the girdle, which supports the greater part of the loading of the carrier, low down on the user's anatomy, allows a considerable degree of freedom of movement to the user.